39 results on '"Maiti AK"'
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2. Evolutionary Shift from Purifying Selection towards Divergent Selection of SARS-CoV2 Favors its Invasion into Multiple Human Organs
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Maiti Ak
- Subjects
Negative selection ,Computational biology ,Biology ,Selection (genetic algorithm) - Abstract
SARS-CoV2 virus is believed to be originated from a closely related bat Coronavirus RaTG13 lineage after gaining insertions of RBD of spike (S) protein by exchanged recombination with pangolin virus Pan_SL_COV_GD. SARSCoV2 uses its entry-point key residues in S1 protein to attach with human ACE2 receptor. SARS-CoV2 evolution comprises any of these possibilities: it entered human from bat with its poorly developed entry-point residues much before its known appearance with slower mutation rate; or recently with efficiently developed entry-point residues having more infective power with higher mutation rate; or through an intermediate host. RaTG13 has 96.3% identity with SARS-CoV2 genome implying that it substituted ~1106 nucleotides to evolute as present-day virus. Temporal analysis of SARS-CoV2 genome from December 2019 shows that its nucleotide substitution rate is as low as 27nt/year with an evolutionary rate of 9x10-4 /site/year, which is a little less than other retrovirus (10-4 to 10-6 /site/year). Estimation of TMRCA of SARS-CoV2 from bat RaTG13 lineage appears to be in between 9-14 years. Furthermore, evolution of a critical entry-point residue Y493Q needs two substitutions with an intermediate virus carrying Y493H (Y>H>Q), although such an intermediate virus has not been identified in known twenty-nine bat CoV virus. Genetic codon analysis indicates that SARS-CoV2 evolution from RaTG13 lineage strictly follows neutral evolution with strong purifying selection whereas its propagation in human disobeys neutral evolution as nonsynonymous mutations surpasses synonymous mutations with the increase of ω (dn/ds) signifying its proceedings towards divergent selection predictably for its infection power to evade multiple organs.
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- 2021
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3. Mutations in the DNAH11 (axonemal heavy chain dynein type 11) gene cause one form of situs inversus totalis and most likely primary ciliary dyskinesia
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UCL, Bartoloni, L, Blouin, JL, Pan, YZ, Gehrig, C, Maiti, AK, Scamuffa, N, Rossier, C, Jorissen, M., Armengot, M, Meeks, M, Mitchison, HM, Chung, EMK, Delozier-Blanchet, CD, Craigen, WJ, Antonarakis, SE, UCL, Bartoloni, L, Blouin, JL, Pan, YZ, Gehrig, C, Maiti, AK, Scamuffa, N, Rossier, C, Jorissen, M., Armengot, M, Meeks, M, Mitchison, HM, Chung, EMK, Delozier-Blanchet, CD, Craigen, WJ, and Antonarakis, SE
- Abstract
Primary ciliary dyskinesia (PCD; MIM 242650) is an autosomal recessive disorder of ciliary dysfunction with extensive genetic heterogeneity. PCD is characterized by bronchiectasis and upper respiratory tract infections, and half of the patients with PCD have situs inversus (Kartagener syndrome). We characterized the transcript and the genomic organization of the axonemal heavy chain dynein type 11 (DNAH11) gene, the human homologue of murine Dnah11 or Ird, which is mutated in the iv/iv mouse model with situs inversus. To assess the role of DNAH11, which maps on chromosome 7p21, we searched for mutations in the 82 exons of this gene in a patient with situs inversus totalis, and probable Kartagener syndrome associated with paternal uniparental disomy of chromosome 7 (patUPD7). We identified a homozygous nonsense mutation (R2852X) in the DNAH11 gene. This patient is remarkable because he is also homozygous for the F508del allele of the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Sequence analysis of the DNAH11 gene in an additional 6 selected PCD sibships that shared DNAH11 alleles revealed polymorphic variants and an R3004Q substitution in a conserved position that might be pathogenic. We conclude that mutations in the coding region of DNAH11 account for situs inversus totalis and probably a minority of cases of PCD.
- Published
- 2002
4. Axonemal beta heavy chain dynein DNAH9: cDNA sequence, genomic structure, and investigation of its role in primary ciliary dyskinesia
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UCL, Bartoloni, L, Blouin, JL, Maiti, AK, Sainsbury, A, Rossier, C, Gehrig, C, She, JX, Marron, MP, Lander, ES, Meeks, M, Chung, E, Armengot, M, Jorissen, M., Scott, HS, Delozier-Blanchet, CD, Gardiner, RM, Antonarakis, SE, UCL, Bartoloni, L, Blouin, JL, Maiti, AK, Sainsbury, A, Rossier, C, Gehrig, C, She, JX, Marron, MP, Lander, ES, Meeks, M, Chung, E, Armengot, M, Jorissen, M., Scott, HS, Delozier-Blanchet, CD, Gardiner, RM, and Antonarakis, SE
- Abstract
Dyneins are multisubunit protein complexes that couple ATPase activity with conformational changes. They are involved in the cytoplasmatic movement of organelles (cytoplasmic dyneins) and the bending of cilia and flagella (axonemal dyneins), Here we present the first complete cDNA and genomic sequences of a human axonemal dynein beta heavy chain gene, DNAH9, which maps to 17p12. The 14-kb-long cDNA is divided into 69 exons spread over 390 kb. The cDNA sequence of DNAH9 was determined using a combination of methods including 5' rapid amplification of cDNA ends, RT-PCR, and cDNA library screening. RT-PCR using nasal epithelium and testis RNA revealed several alternatively spliced transcripts. The genomic structure was determined using three overlapping BACs sequenced by the Whitehead Institute/MIT Center for Genome Research. The predicted protein, of 4486 amino acids, is highly homologous to sea urchin axonemal beta heavy chain dyneins (67% identity). It consists of an N-terminal stem and a globular C-terminus containing the four P-loops that constitute the motor domain. Lack of proper ciliary and flagellar movement characterizes primary ciliary dyskinesia (PCD), a genetically heterogeneous autosomal recessive disorder with respiratory tract infections, bronchiectasis, male subfertility, and, in 50% of cases, situs inversus (Kartagener syndrome, KS). Dyneins are excellent candidate genes for PCD and KS because in over 50% of cases the ultrastructural defects of cilia are related to the dynein complex. Genotype analysis was performed in 31 PCD families with two or more affected siblings using a highly informative dinucleotide polymorphism located in intron 26 of DNAH9, Two families with concordant inheritance of DNAH9 alleles in affected individuals were observed. A mutation search was performed in these two "candidate families," but only polymorphic variants were found. In the absence of pathogenic mutations, the DNAH9 gene has been excluded as being responsible for a
- Published
- 2001
5. Confirmation of an association between rs6822844 at the Il2-Il21 region and multiple autoimmune diseases: evidence of a general susceptibility locus.
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Maiti AK, Kim-Howard X, Viswanathan P, Guillén L, Rojas-Villarraga A, Deshmukh H, Direskeneli H, Saruhan-Direskeneli G, Cañas C, Tobön GJ, Sawalha AH, Cherñavsky AC, Anaya JM, and Nath SK
- Abstract
OBJECTIVE: Autoimmune diseases often have susceptibility genes in common, indicating similar molecular mechanisms. Increasing evidence suggests that rs6822844 at the IL2-IL21 region is strongly associated with multiple autoimmune diseases in individuals of European descent. This study was undertaken to attempt to replicate the association between rs6822844 and 6 different immune-mediated diseases in non-European populations, and to perform disease-specific and overall meta-analyses using data from previously published studies. METHODS: We evaluated case-control associations between rs6822844 and celiac disease (CD) in subjects from Argentina; rheumatoid arthritis (RA), type 1 diabetes mellitus (DM), primary Sjögren's syndrome (SS), and systemic lupus erythematosus (SLE) in subjects from Colombia; and Behçet's disease (BD) in subjects from Turkey. Allele and gene distributions were compared between cases and controls. Meta-analyses were performed using data from the present study and previous studies. RESULTS: We detected significant associations of rs6822844 with SLE (P = 0.008), type 1 DM (P = 0.014), RA (P = 0.019), and primary SS (P = 0.033) but not with BD (P = 0.34) or CD (P = 0.98). We identified little evidence of population differentiation (F(ST) = 0.01) within cases and controls from Argentina and Colombia, suggesting that association was not influenced by population substructure. Disease-specific meta-analysis indicated significant association for RA (P(meta) = 3.61 x 10(-6)), inflammatory bowel disease (IBD; Crohn's disease and ulcerative colitis) (P(meta) = 3.48 x 10(-12)), type 1 DM (P(meta) = 5.33 x 10(-5)), and CD (P(meta) = 5.30 x 10(-3)). Overall meta-analysis across all autoimmune diseases reinforced association with rs6822844 (23 data sets; P(meta) = 2.61 x 10(-25), odds ratio 0.73 [95% confidence interval 0.69-0.78]). CONCLUSION: Our results indicate that there is an association between rs6822844 and multiple autoimmune diseases in non-European populations. Meta-analysis results strongly reinforce this robust association across multiple autoimmune diseases in both European-derived and non-European populations. [ABSTRACT FROM AUTHOR]
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- 2010
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6. Progressive Evolutionary Dynamics of Gene-Specific ω Led to the Emergence of Novel SARS-CoV-2 Strains Having Super-Infectivity and Virulence with Vaccine Neutralization.
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Maiti AK
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- Humans, Virulence genetics, Spike Glycoprotein, Coronavirus genetics, Spike Glycoprotein, Coronavirus immunology, Spike Glycoprotein, Coronavirus metabolism, Mutation, Phylogeny, SARS-CoV-2 genetics, SARS-CoV-2 pathogenicity, SARS-CoV-2 immunology, Evolution, Molecular, COVID-19 Vaccines immunology, COVID-19 virology, COVID-19 immunology, Genome, Viral
- Abstract
An estimation of the proportion of nonsynonymous to synonymous mutation (dn/ds, ω) of the SARS-CoV-2 genome would indicate the evolutionary dynamics necessary to evolve into novel strains with increased infection, virulence, and vaccine neutralization. A temporal estimation of ω of the whole genome, and all twenty-nine SARS-CoV-2 genes of major virulent strains of alpha, delta and omicron demonstrates that the SARS-CoV-2 genome originally emerged (ω ~ 0.04) with a strong purifying selection (ω < 1) and reached (ω ~ 0.85) in omicron towards diversifying selection (ω > 1). A marked increase in the ω occurred in the spike gene from alpha (ω = 0.2) to omicron (ω = 1.97). The ω of the replication machinery genes including RDRP , NSP3 , NSP4 , NSP7 , NSP8 , NSP10 , NSP13 , NSP14 , and ORF9 are markedly increased, indicating that these genes/proteins are yet to be evolutionary stabilized and are contributing to the evolution of novel virulent strains. The delta-specific maximum increase in ω in the immunomodulatory genes of NSP8 , NSP10 , NSP16 , ORF4 , ORF5 , ORF6 , ORF7A , and ORF8 compared to alpha or omicron indicates delta-specific vulnerabilities for severe COVID-19 related hospitalization and death. The maximum values of ω are observed for spike ( S ), NSP4 , ORF8 and NSP15 , which indicates that the gene-specific temporal estimation of ω identifies specific genes for its super-infectivity and virulency that could be targeted for drug development.
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- 2024
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7. Co-release of cytokines after drug-eluting stent implantation in acute myocardial infarction patients with PCI.
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Wan M, Hu K, Lu Y, Wang C, Mao B, Yang Q, Zheng Z, Wu H, Luo Y, and Maiti AK
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- Humans, Cytokines, Metoprolol, Tumor Necrosis Factor-alpha, Angiotensin Receptor Antagonists, C-Reactive Protein, Interleukin-8, Treatment Outcome, Angiotensin-Converting Enzyme Inhibitors, Drug-Eluting Stents, Percutaneous Coronary Intervention adverse effects, Non-ST Elevated Myocardial Infarction surgery, Myocardial Infarction surgery, Myocardial Infarction etiology
- Abstract
Acute Myocardial Infarction (AMI) after Percutaneous Coronary Intervention (PCI) often requires stent implantation leading to cardiovascular injury and cytokine release. Stent implantation induces cytokines production including TNFα, Hs-CRP, IL-1ß, IL2 receptor, IL6, IL8, and IL10, but their co-release is not extensively established. In 311 PCI patients with Drug-Eluting Stent (DES) implantation, we statistically evaluate the correlation of these cytokines release in various clinical conditions, stent numbers, and medications. We observed that TNFα is moderately correlated with IL-1ß (r
2 = 0.59, p = 0.001) in diabetic PCI patients. Similarly, in NSTEMI (Non-ST Segment Elevation) patients, TNFα is strongly correlated with both IL-1ß (r2 = 0.97, p = 0.001) and IL8 (r2 = 0.82, p = 0.001). In CAD (Coronary Artery Disease)-diagnosed patients TNFα is highly correlated (r2 = 0.84, p = 0.0001) with IL8 release but not with IL-1ß. In patients with an increased number of stents, Hs-CRP is significantly coupled with IL8 > 5 pg/ml (t-statistic = 4.5, p < 0.0001). Inflammatory suppressor drugs are correlated as TNFα and IL8 are better suppressed by Metoprolol 23.75 (r2 = 0.58, p < 0.0001) than by Metoprolol 11.87 (r2 = 0.80, p = 0.5306). Increased TNFα and IL-1ß are better suppressed by the antiplatelet drug Brilinta (r2 = 0.30, p < 0.0001) but not with Clopidogrel (r2 = 0.87, p < 0.0001). ACI/ARB Valsartan 80 (r2 = 0.43, p = 0.0011) should be preferred over Benazepril 5.0 (r2 = 0.9291, p < 0.0001) or Olmesartan (r2 = 0.90, p = 0.0001). Thus, the co-release of IL-1ß, IL8 with TNFα, or only IL8 with TNFα could be a better predictor for the outcome of stent implantation in NSTEMI and CAD-diagnosed AMI patients respectively. Cytokine suppressive medications should be chosen carefully to inhibit further cardiovascular damage., (© 2024. The Author(s).)- Published
- 2024
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8. A randomised, double-blind, comparative study of preoperative magnesium sulphate versus zinc sulphate gargle for prevention of postoperative sore throat following endotracheal intubation.
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Mondal AK, Maiti AK, Chattopadhyay S, and Bhar D
- Abstract
Background and Aims: Magnesium sulphate and zinc sulphate have been reported to attenuate postoperative sore throat (POST). The study aims to compare the effect of preoperative magnesium sulphate and zinc sulphate gargle on the incidence and severity of POST following endotracheal intubation within 24 h., Methods: After ethics committee approval, 132 patients were randomly allocated to three groups (M, Z and D). Fifteen minutes before laryngoscopy and tracheal intubation, patients assigned to groups M and Z received a solution for gargle containing magnesium sulphate 20 mg/kg and zinc sulphate containing 40 mg of elemental zinc dissolved in 20 ml of 5% dextrose solution, respectively. Group D received 20 ml of 5% dextrose solution. Incidence and severity of POST (4-point score: Grade 0- no sore throat, Grade 1- mild sore throat, Grade 2- moderate sore throat, Grade 3- severe sore throat) was assessed for 24 h after extubation. Statistica, Version 8.0 (StatSoft, Inc., Tulsa, Oklahoma, USA) was used for analysing the data., Results: The lowest incidence of POST in group M was 13.6% (95% confidence interval [CI] 3.5-23.7) compared to 0% in group Z, whereas the highest incidence recorded in group M was 25% (95% CI 12.2-37.7) in contrast to 13.6% (95% CI 3.5-23.7) in group Z during the first 24 h after operation. It was observed that the incidence of mild POST (POST score 1) was significantly lower ( P < 0.05) in group Z compared to group M in the first 4 h postoperatively., Conclusion: Zinc sulphate gargle before laryngoscopy and tracheal intubation is more effective for reducing the incidence of POST than magnesium sulphate gargle., Competing Interests: There are no conflicts of interest., (Copyright: © 2023 Indian Journal of Anaesthesia.)
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- 2023
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9. Urinary Cytokines as Potential Biomarkers of Mild Cognitive Impairment and Alzheimer's Disease: A Pilot Study.
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Saiyed N, Yilmaz A, Vishweswariah S, Maiti AK, Ustun I, Bartolone S, Brown-Hughes T, Thorpe RJ, Osentoski T, Ruff S, Pai A, Maddens M, Imam K, and Graham SF
- Abstract
Background: Alzheimer's disease (AD) is the most common form of dementia, accounting for 80% of all cases. Mild cognitive impairment (MCI) is a transitional state between normal aging and AD. Early detection is crucial, as irreversible brain damage occurs before symptoms manifest., Objective: This study aimed to identify potential biomarkers for early detection of AD by analyzing urinary cytokine concentrations. We investigated 37 cytokines in AD, MCI, and cognitively normal individuals (NC), assessing their associations with AD development., Methods: Urinary cytokine concentrations were measured in AD ( n = 25), MCI ( n = 25), and NC ( n = 26) patients. IL6ST and MMP-2 levels were compared between AD and NC, while TNFRSF8, IL6ST, and IL-19 were assessed in AD versus MCI. Diagnostic models distinguished AD from NC, and in-silico analysis explored molecular mechanisms related to AD., Results: Significant perturbations in IL6ST and MMP-2 concentrations were observed in AD urine compared to NC, suggesting their potential as biomarkers. TNFRSF8, IL6ST, and IL-19 differed significantly between AD and MCI, implicating them in disease progression. Diagnostic models exhibited promising performance (AUC: 0.59-0.79, sensitivity: 0.72-0.80, specificity: 0.56-0.78) in distinguishing AD from NC. In-silico analysis revealed molecular insights, including relevant non-coding RNAs, microRNAs, and transcription factors., Conclusion: This study establishes significant associations between urinary cytokine concentrations and AD and MCI. IL6ST, MMP-2, TNFRSF8, IL6ST, and IL-19 emerge as potential biomarkers for early detection of AD. In-silico analysis enhances understanding of molecular mechanisms in AD. Further validation and exploration of these biomarkers in larger cohorts are warranted to assess their clinical utility., Competing Interests: The authors have no conflict of interest to report., (© 2023 – The authors. Published by IOS Press.)
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- 2023
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10. Melatonin ameliorates lipopolysaccharide induced brain inflammation through modulation of oxidative status and diminution of cytokine rush in Danio rerio.
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Moniruzzaman M, Maiti AK, Chakraborty SB, Saha I, and Saha NC
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- Animals, Lipopolysaccharides toxicity, Cytokines metabolism, NF-E2-Related Factor 2 metabolism, Zebrafish metabolism, Oxidative Stress, NF-kappa B metabolism, Inflammation chemically induced, Inflammation drug therapy, Inflammation pathology, Melatonin pharmacology, Melatonin therapeutic use, Encephalitis
- Abstract
Lipopolysaccharide (LPS) is known to induce inflammation and immunonomodulation in a piscine model of Danio rerio. Present study aimed to explore the ability of melatonin in attenuating LPS-induced oxidative damages using this model. In LPS-exposed fish, activation of stress marker MDA was observed in brain with corresponding augmentation of multiple pro-inflammatory cytokines (IL1β, IL6, IL10 and TNFα). In addition, it also showed marked increase in the levels of heat shock factor (HSF) and heat shock proteins (HSPs) in association with transcription factors (NF-kB and NRF2) and mitogen-activated protein kinases (MAPKs). The changes in the levels of these mediators are highly correlated with the induction of pro-inflammatory cytokines. In melatonin-treated fishes, significant amelioration of oxidative stress was observed with reduced levels of MDA and pro-inflammatory cytokines. Melatonin also modulated expression of HSPs that facilitated the brain to overcome inflammation-induced stress by directly initiating NFkB/NRF2 translocation. In summary, melatonin effectively functions to reduce stress induced inflammatory signalling through modulation of oxidative stress and protects the brain from the neuropathological insult., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)
- Published
- 2022
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11. Implications of Gut Microbiota in Complex Human Diseases.
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Yu D, Meng X, de Vos WM, Wu H, Fang X, and Maiti AK
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- Anti-Bacterial Agents adverse effects, Dysbiosis etiology, Fecal Microbiota Transplantation, Humans, Prebiotics adverse effects, Probiotics adverse effects, Diet adverse effects, Dysbiosis therapy, Gastrointestinal Microbiome drug effects
- Abstract
Humans, throughout the life cycle, from birth to death, are accompanied by the presence of gut microbes. Environmental factors, lifestyle, age and other factors can affect the balance of intestinal microbiota and their impact on human health. A large amount of data show that dietary, prebiotics, antibiotics can regulate various diseases through gut microbes. In this review, we focus on the role of gut microbes in the development of metabolic, gastrointestinal, neurological, immune diseases and, cancer. We also discuss the interaction between gut microbes and the host with respect to their beneficial and harmful effects, including their metabolites, microbial enzymes, small molecules and inflammatory molecules. More specifically, we evaluate the potential ability of gut microbes to cure diseases through Fecal Microbial Transplantation (FMT), which is expected to become a new type of clinical strategy for the treatment of various diseases.
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- 2021
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12. Expression Signatures of Long Noncoding RNAs in Left Ventricular Noncompaction.
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Tian Q, Niu H, Liu D, Ta N, Yang Q, Norton V, Wu Y, Maiti AK, Wu H, and Zheng Z
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Long noncoding RNAs have gained widespread attention in recent years for their crucial role in biological regulation. They have been implicated in a range of developmental processes and diseases including cancer, cardiovascular, and neuronal diseases. However, the role of long noncoding RNAs (lncRNAs) in left ventricular noncompaction (LVNC) has not been explored. In this study, we investigated the expression levels of lncRNAs in the blood of LVNC patients and healthy subjects to identify differentially expressed lncRNA that develop LVNC specific biomarkers and targets for developing therapies using biological pathways. We used Agilent Human lncRNA array that contains both updated lncRNAs and mRNAs probes. We identified 1,568 upregulated and 1,141 downregulated (log fold-change > 2.0) lncRNAs that are differentially expressed between LVNC and the control group. Among them, RP11-1100L3.7 and XLOC_002730 are the most upregulated and downregulated lncRNAs. Using quantitative real-time reverse transcription polymerase chain reaction (RT-QPCR), we confirmed the differential expression of three top upregulated and downregulated lncRNAs along with two other randomly picked lncRNAs. Gene Ontology (GO) and KEGG pathways analysis with these differentially expressed lncRNAs provide insight into the cellular pathway leading to LVNC pathogenesis. We also identified 1,066 upregulated and 1,017 downregulated mRNAs. Gene set enrichment analysis (GSEA) showed that G2M, Estrogen, and inflammatory pathways are enriched in differentially expressed genes (DEG). We also identified miRNA targets for these differentially expressed genes. In this study, we first report the use of LncRNA microarray to understand the pathogenesis of LVNC and to identify several lncRNA and genes and their targets as potential biomarkers., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Tian, Niu, Liu, Ta, Yang, Norton, Wu, Maiti, Wu and Zheng.)
- Published
- 2021
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13. Development of Biomarkers and Molecular Therapy Based on Inflammatory Genes in Diabetic Nephropathy.
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Maiti AK
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- Animals, Autophagy genetics, Diabetic Nephropathies epidemiology, Diabetic Nephropathies pathology, Humans, Mutation genetics, Biomarkers metabolism, Diabetic Nephropathies drug therapy, Diabetic Nephropathies genetics, Inflammation genetics, Molecular Targeted Therapy
- Abstract
Diabetic Nephropathy (DN) is a debilitating consequence of both Type 1 and Type 2 diabetes affecting the kidney and renal tubules leading to End Stage Renal Disease (ESRD). As diabetes is a world epidemic and almost half of diabetic patients develop DN in their lifetime, a large group of people is affected. Due to the complex nature of the disease, current diagnosis and treatment are not adequate to halt disease progression or provide an effective cure. DN is now considered a manifestation of inflammation where inflammatory molecules regulate most of the renal physiology. Recent advances in genetics and genomic technology have identified numerous susceptibility genes that are associated with DN, many of which have inflammatory functions. Based on their role in DN, we will discuss the current aspects of developing biomarkers and molecular therapy for advancing precision medicine.
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- 2021
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14. RIP1/RIP3/MLKL Mediates Myocardial Function Through Necroptosis in Experimental Autoimmune Myocarditis.
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Wu Y, Zheng Z, Cao X, Yang Q, Norton V, Adini A, Maiti AK, Adini I, and Wu H
- Abstract
Cardiomyopathy often leads to dilated cardiomyopathy (DCM) when caused by viral myocarditis. Apoptosis is long considered as the principal process of cell death in cardiomyocytes, but programmed necrosis or necroptosis is recently believed to play an important role in cardiomyocyte cell death. We investigated the role of necroptosis and its interdependency with other processes of cell death, autophagy, and apoptosis in a rat system of experimental autoimmune myocarditis (EAM). We successfully created a rat model system of EAM by injecting porcine cardiac myosin (PCM) and showed that in EAM, all three forms of cell death increase considerably, resulting in the deterioration of cardiac conditions with an increase in inflammatory infiltration in cardiomyocytes. To explore whether necroptosis occurs in EAM rats independent of autophagy, we treated EAM rats with a RIP1/RIP3/MLKL kinase-mediated necroptosis inhibitor, Necrostatin-1 (Nec-1). In Nec-1 treated rats, cell death proceeds through apoptosis but has no significant effect on autophagy. In contrast, autophagy inhibitor 3-Methyl Adenine (3-MA) increases necroptosis, implying that blockage of autophagy must be compensated through necroptosis. Caspase 8 inhibitor zVAD-fmk blocks apoptosis but increases both necroptosis and autophagy. However, all necroptosis, apoptosis, and autophagy inhibitors independently reduce inflammatory infiltration in cardiomyocytes and improve cardiac conditions. Since apoptosis or autophagy is involved in many important cellular aspects, instead of suppressing these two major cell death processes, Nec1 can be developed as a potential therapeutic target for inflammatory myocarditis., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Wu, Zheng, Cao, Yang, Norton, Adini, Maiti, Adini and Wu.)
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- 2021
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15. Substance P failed to reverse dextran sulfate sodium-induced murine colitis mediated by mitochondrial dysfunction: implications in ulcerative colitis.
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Chandraiah SB, Ghosh S, Saha I, More SS, Annappa GS, and Maiti AK
- Abstract
As controversy exists about the efficacy of substance P (SP) in treating ulcerative colitis (UC) with no previous study highlighting the impact of SP on mitochondrial dysfunction in this diseased condition, it became logical to perform the present study. C57BL/6 J mice were administered with DSS @ 3.5%/gm body weight for 3 cycles of 5 days each followed by i.v. dose of SP @ 5nmole per kg for consecutive 7 days. Histopathological features were noticed in the affected colon along with colonic mitochondrial dysfunction, alterations in mitochondrial stress variables and enhanced colonic cell death. Interestingly, SP failed to reverse colitic features and proved ineffective in inhibiting mitochondrial dysfunction. Unexpectedly SP alone seemed to impart detrimental effects on some of the mitochondrial functions, enhanced lipid peroxidation and increased staining intensities for caspases 3 and 9 in the normal colon. To substantiate in vivo findings and to assess free radical scavenging property of SP, Caco-2 cells were exposed to DSS with or without SP in the presence and absence of specific free radical scavengers and antioxidants. Interestingly, in vitro treatment with SP failed to restore mitochondrial functions and its efficacy proved below par compared to SOD and DMSO indicating involvement of O
2 •- and• OH in the progression of UC. Besides, catalase, L-NAME and MEG proved ineffective indicating non-involvement of H2 O2, NO and ONOO- in UC. Thus, SP may not be a potent anti-colitogenic agent targeting colonic mitochondrial dysfunction for maintenance of colon epithelial tract as it lacks free radical scavenging property., Competing Interests: Conflict of interestThe authors declare that they have no conflict of interest in the publication., (© King Abdulaziz City for Science and Technology 2021.)- Published
- 2021
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16. Mitochondrial respiratory chain inhibition and Na + K + ATPase dysfunction are determinant factors modulating the toxicity of nickel in the brain of indian catfish Clarias batrachus L.
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Maiti AK, Saha NC, Paul G, and Dhara K
- Abstract
Nickel is a potential neurotoxic pollutant inflicting damage in living organisms, including fish, mainly through oxidative stress. Previous studies have demonstrated the impact of nickel toxicity on mitochondrial function, but there remain lacunae on the damage inflicted at mitochondrial respiratory level. Deficient mitochondrial function usually affects the activities of important adenosinetriphosphatases responsible for the maintenance of normal neuronal function, namely Na
+ K+ ATPase, as explored in our study. Previous reports demonstrated the dysfunction of this enzyme upon nickel exposure but the contributing factors for the inhibition of this enzyme remained unexplored. The main purpose of this study was to elucidate the impact of nickel neurotoxicity on mitochondrial respiratory complexes and Na+ K+ ATPase in the piscine brain and to determine the contributing factors that had an impact on the same. Adult Clarias batrachus were exposed to nickel treated water at 10% and 20% of the 96 h LC50 value (41 mg.l-1 ) respectively and sampled on 20, 40 and 60 days. Exposure of fish brain to nickel led to partial inhibition of complex IV of mitochondrial respiratory chain, however, the activities of complex I, II and III remained unaltered. This partial inhibition of mitochondrial respiratory chain might have been sufficient to lower mitochondrial energy production in mitochondria that contributed to the partial dysfunction of Na+ K+ ATPase. Besides energy depletion other contributing factors were involved in the dysfunction of this enzyme, like loss of thiol groups for enzyme activity and lipid peroxidation-derived end products that might have induced conformational and functional changes. However, providing direct evidence for such conformational and functional changes of Na+ K+ ATPase was beyond the scope of the present study. In addition, immunoblotting results also showed a decrease in Na+ K+ ATPase protein expression highlighting the impact of nickel neurotoxicity on the expression of the enzyme itself. The implication of the inhibition of mitochondrial respiration and Na+ K+ ATPase dysfunction was the neuronal death as evidenced by enhanced caspase-3 and caspase-9 activities. Thus, this study established the deleterious impact of nickel neurotoxicity on mitochondrial functions in the piscine brain and identified probable contributing factors that can act concurrently in the inhibition of Na+ K+ ATPase. This study also provided a vital clue about the specific areas that the therapeutic agents should target to counter nickel neurotoxicity., (Copyright © 2018 SETOX & Institute of Experimental Pharmacology and Toxicology, SASc.)- Published
- 2018
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17. Colonic levels of vasoactive intestinal peptide decrease during infection and exogenous VIP protects epithelial mitochondria against the negative effects of IFNγ and TNFα induced during Citrobacter rodentium infection.
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Maiti AK, Sharba S, Navabi N, and Lindén SK
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- Animals, Colitis drug therapy, Colitis immunology, Colitis metabolism, Disease Models, Animal, Electron Transport Complex I metabolism, Electron Transport Complex IV metabolism, Enterobacteriaceae Infections drug therapy, HT29 Cells, Host Microbial Interactions, Humans, Interferon-gamma metabolism, Intestinal Mucosa immunology, Intestinal Mucosa metabolism, Male, Mice, Mice, Inbred C57BL, Mitochondria metabolism, Tumor Necrosis Factor-alpha metabolism, Vasoactive Intestinal Peptide administration & dosage, Vasoactive Intestinal Peptide immunology, Citrobacter rodentium pathogenicity, Colon immunology, Colon metabolism, Enterobacteriaceae Infections immunology, Enterobacteriaceae Infections metabolism, Vasoactive Intestinal Peptide metabolism
- Abstract
Citrobacter rodentium infection is a model for infection with attaching and effacing pathogens, such as enteropathogenic Escherichia coli. The vasoactive intestinal peptide (VIP) has emerged as an anti-inflammatory agent, documented to inhibit Th1 immune responses and successfully treat animal models of inflammation. VIP is also a mucus secretagogue. Here, we found that colonic levels of VIP decrease during murine C. rodentium infection with a similar time dependency as measurements reflecting mitochondrial function and epithelial integrity. The decrease in VIP appears mainly driven by changes in the cytokine environment, as no changes in VIP levels were detected in infected mice lacking interferon gamma (IFNγ). VIP supplementation alleviated the reduction of activity and levels of mitochondrial respiratory complexes I and IV, mitochondrial phosphorylation capacity, transmembrane potential and ATP generation caused by IFNγ, TNFα and C. rodentium infection, in an in vitro mucosal surface. Similarly, VIP treatment regimens that included the day 5-10 post infection period alleviated decreases in enzyme complexes I and IV, phosphorylation capacity, mitochondrial transmembrane potential and ATP generation as well as increased apoptosis levels during murine infection with C. rodentium. However, VIP treatment failed to alleviate colitis, although there was a tendency to decreased pathogen density in contact with the epithelium and in the spleen. Both in vivo and in vitro, NO generation increased during C. rodentium infection, which was alleviated by VIP. Thus, therapeutic VIP administration to restore the decreased levels during infection had beneficial effects on epithelial cells and their mitochondria, but not on the overall infection outcome., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2018
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18. Immunohistochemical evaluation of prime molecules in cervical lesions towards assessment of malignant potentiality.
- Author
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Das L, Naskar S, Sarkar T, Maiti AK, Das S, and Chatterjee J
- Subjects
- Adult, Aged, Biomarkers, Biopsy, Cadherins metabolism, Endoglin metabolism, Female, Humans, Immunohistochemistry, Middle Aged, Transcription Factors metabolism, Tumor Suppressor Proteins metabolism, Uterine Cervical Neoplasms metabolism, Uterine Cervical Neoplasms pathology, Uterine Cervical Dysplasia metabolism, Uterine Cervical Dysplasia pathology, Cell Transformation, Neoplastic metabolism, Cervix Uteri metabolism, Cervix Uteri pathology
- Abstract
Objective: A comparative immunohistochemical evaluation of p63, CD105, and E-cadherin expression pattern in histopathologically confirmed normal cervical epithelium (NCM), dysplastic cervical epithelium (DYS) and squamous cell carcinoma (SCC) of uterine cervix towards assessing malignant potentiality of the precancerous condition., Materials and Methods: The biopsies from cervical mucosa (normal, dysplasia, and cancer) were studied by routine hematoxylin and eosin (H and E) and by immunohistochemistry for p63, E-cadherin, and CD105 expression. The expressions of these molecules were assessed in a semiquantitative way by (i) counting p63 cell population and distribution, (ii) intensity scoring of E-cadherin along the expression path, and (iii) measuring CD105 expression density., Result: p63
+ cells were highest in carcinomas followed by dysplasia and normal. An abrupt increase in CD105 expression was observed through change of normal to dysplasia and cancer. A decrease in membranous E-cadherin expression was noticed in the transformation from normal to precancer and cancers., Conclusion: The malignant potential of the dysplastic conditions is likely to be correlated with upregulation in p63 and CD105 expression and a simultaneous downregulation of membranous E-cadherin., Competing Interests: There are no conflicts of interest.- Published
- 2018
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19. Enhancement in cellular Na+K+ATPase activity by low doses of peroxynitrite in mouse renal tissue and in cultured HK2 cells.
- Author
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Maiti AK, Islam MT, Satou R, and Majid DS
- Subjects
- Animals, Cell Line, Cell Membrane enzymology, Dose-Response Relationship, Drug, Enzyme Inhibitors pharmacology, Epithelial Cells enzymology, Free Radical Scavengers pharmacology, Humans, Kidney Tubules, Proximal enzymology, Mice, Inbred C57BL, Nitric Oxide metabolism, Sodium-Potassium-Exchanging ATPase antagonists & inhibitors, Time Factors, Cell Membrane drug effects, Enzyme Activators pharmacology, Epithelial Cells drug effects, Kidney Tubules, Proximal drug effects, Peroxynitrous Acid pharmacology, Sodium-Potassium-Exchanging ATPase metabolism
- Abstract
In the normal condition, endogenous formation of peroxynitrite (ONOO-) from the interaction of nitric oxide and superoxide has been suggested to play a renoprotective role. However, the exact mechanism associated with renoprotection by this radical compound is not yet clearly defined. AlthoughONOO- usually inhibits renal tubular Na(+)K(+)ATPase (NKA) activity at high concentrations (micromolar to millimolar range [μM-mM], achieved in pathophysiological conditions), the effects at lower concentrations (nanomolar range [nM], relevant in normal condition) remain unknown. To examine the direct effect ofONOO- onNKAactivity, preparations of cellular membrane fraction from mouse renal tissue and from culturedHK2 cells (human proximal tubular epithelial cell lines) were incubated for 10 and 30 min each with different concentrations ofONOO- (10 nmol/L-200 μmol/L).NKAactivity in these samples (n = 5 in each case) was measured via a colorimetric assay capable of detecting inorganic phosphate. At high concentrations (1-200 μmol/L),ONOO- caused dose-dependent inhibition ofNKAactivity (-3.0 ± 0.6% and -36.4 ± 1.4%). However,NKAactivity remained unchanged at 100 and 500 nmol/LONOO- concentration, but interestingly, at lower concentrations (10 and 50 nmol/L),ONOO- caused small but significant increases in theNKAactivity (3.3 ± 1.1% and 3.1 ± 0.6%). Pretreatment with aONOO- scavenger, mercaptoethylguanidine (MEG; 200 μmol/L), prevented these biphasic responses toONOO-. This dose-dependent biphasic action ofONOO(-)onNKAactivity may implicate that this radical compound helps to maintain sodium homeostasis either by enhancing tubular sodium reabsorption under normal conditions or by inhibiting it during oxidative stress conditions., (© 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.)
- Published
- 2016
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20. IL-4 Protects the Mitochondria Against TNFα and IFNγ Induced Insult During Clearance of Infection with Citrobacter rodentium and Escherichia coli.
- Author
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Maiti AK, Sharba S, Navabi N, Forsman H, Fernandez HR, and Lindén SK
- Subjects
- Adenosine Triphosphate biosynthesis, Animals, Caspase 3 metabolism, Cell Death, Colitis genetics, Colitis metabolism, Colitis microbiology, Colitis pathology, Cytokines genetics, Cytokines metabolism, Disease Models, Animal, Electron Transport Chain Complex Proteins metabolism, Enterobacteriaceae Infections genetics, Enterobacteriaceae Infections pathology, Enzyme Activation, Interferon-gamma genetics, Membrane Potential, Mitochondrial, Mice, Mice, Knockout, Mitochondria drug effects, Nitric Oxide metabolism, Organophosphorus Compounds pharmacology, Phosphorylation, Ubiquinone analogs & derivatives, Ubiquinone pharmacology, Citrobacter rodentium, Enterobacteriaceae Infections metabolism, Enterobacteriaceae Infections microbiology, Escherichia coli, Interferon-gamma metabolism, Interleukin-4 metabolism, Mitochondria metabolism, Tumor Necrosis Factor-alpha metabolism
- Abstract
Citrobacter rodentium is a murine pathogen that serves as a model for enteropathogenic Escherichia coli. C. rodentium infection reduced the quantity and activity of mitochondrial respiratory complexes I and IV, as well as phosphorylation capacity, mitochondrial transmembrane potential and ATP generation at day 10, 14 and 19 post infection. Cytokine mRNA quantification showed increased levels of IFNγ, TNFα, IL-4, IL-6, and IL-12 during infection. The effects of adding these cytokines, C. rodentium and E. coli were hence elucidated using an in vitro colonic mucosa. Both infection and TNFα, individually and combined with IFNγ, decreased complex I and IV enzyme levels and mitochondrial function. However, IL-4 reversed these effects, and IL-6 protected against loss of complex IV. Both in vivo and in vitro, the dysfunction appeared caused by nitric oxide-generation, and was alleviated by an antioxidant targeting mitochondria. IFNγ -/- mice, containing a similar pathogen burden but higher IL-4 and IL-6, displayed no loss of any of the four complexes. Thus, the cytokine environment appears to be a more important determinant of mitochondrial function than direct actions of the pathogen. As IFNγ and TNFα levels increase during clearance of infection, the concomitant increase in IL-4 and IL-6 protects mitochondrial function.
- Published
- 2015
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21. Integrated cervical smear screening using liquid based cytology and bioimpedance analysis.
- Author
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Das L, Sarkar T, Maiti AK, Naskar S, Das S, and Chatterjee J
- Abstract
Objective: To minimize the false negativity in cervical cancer screening with Papanicolaou (Pap) test, there is a need to explore novel cytological technique and identification of unique and important cellular features from the perspectives of morphological as well as biophysical properties., Materials and Methods: The present study explores the feasibility of low-cost cervical monolayer techniques in extracting cyto-pathological features to classify normal and abnormal conditions. The cervical cells were also analyzed in respect to their electrical bioimpedance., Result: The results show that newly developed monolayer technique for cervical smears is cost effective, capable of cyto-pathological evaluation. Electrical bioimpedance study evidenced distinction between abnormal and normal cell population at more than two order of magnitude difference., Conclusion: The integration of bioimpedance observation along with the proposed low-cost monolayer technology could increase the efficiency of the cervical screening to a greater extent thereby reducing the rates of faulty diagnosis.
- Published
- 2014
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22. Combined protein- and nucleic acid-level effects of rs1143679 (R77H), a lupus-predisposing variant within ITGAM.
- Author
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Maiti AK, Kim-Howard X, Motghare P, Pradhan V, Chua KH, Sun C, Arango-Guerrero MT, Ghosh K, Niewold TB, Harley JB, Anaya JM, Looger LL, and Nath SK
- Subjects
- Alleles, Antigens, Nuclear genetics, Antigens, Nuclear metabolism, CD11b Antigen metabolism, Chromatin metabolism, Chromatin pathology, DNA-Binding Proteins genetics, DNA-Binding Proteins metabolism, Female, Fibrinogen genetics, Fibrinogen metabolism, Gene Expression Regulation, Gene Frequency, Humans, Ku Autoantigen, Lupus Erythematosus, Systemic ethnology, Lupus Erythematosus, Systemic metabolism, Lupus Erythematosus, Systemic pathology, Male, Monocytes pathology, NF-kappa B p50 Subunit genetics, NF-kappa B p50 Subunit metabolism, Odds Ratio, Polymorphism, Genetic, Protein Binding, RNA, Messenger metabolism, Racial Groups, Risk, Trans-Activators genetics, Trans-Activators metabolism, Transcription, Genetic, Vitronectin genetics, Vitronectin metabolism, CD11b Antigen genetics, Genetic Predisposition to Disease, Lupus Erythematosus, Systemic genetics, Monocytes metabolism, RNA, Messenger genetics
- Abstract
Integrin alpha M (ITGAM; CD11b) is a component of the macrophage-1 antigen complex, which mediates leukocyte adhesion, migration and phagocytosis as part of the immune system. We previously identified a missense polymorphism, rs1143679 (R77H), strongly associated with systemic lupus erythematosus (SLE). However, the molecular mechanisms of this variant are incompletely understood. A meta-analysis of published and novel data on 28 439 individuals with European, African, Hispanic and Asian ancestries reinforces genetic association between rs1143679 and SLE [Pmeta = 3.60 × 10(-90), odds ratio (OR) = 1.76]. Since rs1143679 is in the most active region of chromatin regulation and transcription factor binding in ITGAM, we quantitated ITGAM RNA and surface protein levels in monocytes from patients with each rs1143679 genotype. We observed that transcript levels significantly decreased for the risk allele ('A') relative to the non-risk allele ('G'), in a dose-dependent fashion: ('AA' < 'AG' < 'GG'). CD11b protein levels in patients' monocytes were directly correlated with RNA levels. Strikingly, heterozygous individuals express much lower (average 10- to 15-fold reduction) amounts of the 'A' transcript than 'G' transcript. We found that the non-risk sequence surrounding rs1143679 exhibits transcriptional enhancer activity in vivo and binds to Ku70/80, NFKB1 and EBF1 in vitro, functions that are significantly reduced with the risk allele. Mutant CD11b protein shows significantly reduced binding to fibrinogen and vitronectin, relative to non-risk, both in purified protein and in cellular models. This two-pronged contribution (nucleic acid- and protein-level) of the rs1143679 risk allele to decreasing ITGAM activity provides insight into the molecular mechanisms of its potent association with SLE., (© The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)
- Published
- 2014
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23. Allelic heterogeneity in NCF2 associated with systemic lupus erythematosus (SLE) susceptibility across four ethnic populations.
- Author
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Kim-Howard X, Sun C, Molineros JE, Maiti AK, Chandru H, Adler A, Wiley GB, Kaufman KM, Kottyan L, Guthridge JM, Rasmussen A, Kelly J, Sánchez E, Raj P, Li QZ, Bang SY, Lee HS, Kim TH, Kang YM, Suh CH, Chung WT, Park YB, Choe JY, Shim SC, Lee SS, Han BG, Olsen NJ, Karp DR, Moser K, Pons-Estel BA, Wakeland EK, James JA, Harley JB, Bae SC, Gaffney PM, Alarcón-Riquelme M, Looger LL, and Nath SK
- Subjects
- Black or African American genetics, Asian genetics, Computational Biology, Genetic Heterogeneity, Genetic Variation, Haplotypes, Hispanic or Latino genetics, Humans, Models, Molecular, Polymorphism, Single Nucleotide, White People ethnology, White People genetics, Genetic Association Studies methods, Genetic Predisposition to Disease, Lupus Erythematosus, Systemic ethnology, Lupus Erythematosus, Systemic genetics, NADPH Oxidases genetics
- Abstract
Recent reports have associated NCF2, encoding a core component of the multi-protein NADPH oxidase (NADPHO), with systemic lupus erythematosus (SLE) susceptibility in individuals of European ancestry. To identify ethnicity-specific and -robust variants within NCF2, we assessed 145 SNPs in and around the NCF2 gene in 5325 cases and 21 866 controls of European-American (EA), African-American (AA), Hispanic (HS) and Korean (KR) ancestry. Subsequent imputation, conditional, haplotype and bioinformatic analyses identified seven potentially functional SLE-predisposing variants. Association with non-synonymous rs17849502, previously reported in EA, was detected in EA, HS and AA (P(EA) = 1.01 × 10(-54), PHS = 3.68 × 10(-10), P(AA) = 0.03); synonymous rs17849501 was similarly significant. These SNPs were monomorphic in KR. Novel associations were detected with coding variants at rs35937854 in AA (PAA = 1.49 × 10(-9)), and rs13306575 in HS and KR (P(HS) = 7.04 × 10(-7), P(KR) = 3.30 × 10(-3)). In KR, a 3-SNP haplotype was significantly associated (P = 4.20 × 10(-7)), implying that SLE predisposing variants were tagged. Significant SNP-SNP interaction (P = 0.02) was detected between rs13306575 and rs17849502 in HS, and a dramatically increased risk (OR = 6.55) with a risk allele at each locus. Molecular modeling predicts that these non-synonymous mutations could disrupt NADPHO complex assembly. The risk allele of rs17849501, located in a conserved transcriptional regulatory region, increased reporter gene activity, suggesting in vivo enhancer function. Our results not only establish allelic heterogeneity within NCF2 associated with SLE, but also emphasize the utility of multi-ethnic cohorts to identify predisposing variants explaining additional phenotypic variance ('missing heritability') of complex diseases like SLE.
- Published
- 2014
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24. Admixture mapping in lupus identifies multiple functional variants within IFIH1 associated with apoptosis, inflammation, and autoantibody production.
- Author
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Molineros JE, Maiti AK, Sun C, Looger LL, Han S, Kim-Howard X, Glenn S, Adler A, Kelly JA, Niewold TB, Gilkeson GS, Brown EE, Alarcón GS, Edberg JC, Petri M, Ramsey-Goldman R, Reveille JD, Vilá LM, Freedman BI, Tsao BP, Criswell LA, Jacob CO, Moore JH, Vyse TJ, Langefeld CL, Guthridge JM, Gaffney PM, Moser KL, Scofield RH, Alarcón-Riquelme ME, Williams SM, Merrill JT, James JA, Kaufman KM, Kimberly RP, Harley JB, and Nath SK
- Subjects
- Alleles, Antigens, Nuclear genetics, Antigens, Nuclear immunology, Apoptosis genetics, Autoantibodies genetics, Autoantibodies immunology, Chromosome Mapping, DNA-Binding Proteins genetics, DNA-Binding Proteins immunology, Genetic Predisposition to Disease, Genome, Human, Haplotypes, Humans, Inflammation genetics, Interferon-Induced Helicase, IFIH1, Ku Autoantigen, Lupus Erythematosus, Systemic immunology, Polymorphism, Single Nucleotide, Protein Binding, White People genetics, Black or African American genetics, DEAD-box RNA Helicases genetics, Lupus Erythematosus, Systemic genetics
- Abstract
Systemic lupus erythematosus (SLE) is an inflammatory autoimmune disease with a strong genetic component. African-Americans (AA) are at increased risk of SLE, but the genetic basis of this risk is largely unknown. To identify causal variants in SLE loci in AA, we performed admixture mapping followed by fine mapping in AA and European-Americans (EA). Through genome-wide admixture mapping in AA, we identified a strong SLE susceptibility locus at 2q22-24 (LOD=6.28), and the admixture signal is associated with the European ancestry (ancestry risk ratio ~1.5). Large-scale genotypic analysis on 19,726 individuals of African and European ancestry revealed three independently associated variants in the IFIH1 gene: an intronic variant, rs13023380 [P(meta) = 5.20×10(-14); odds ratio, 95% confidence interval = 0.82 (0.78-0.87)], and two missense variants, rs1990760 (Ala946Thr) [P(meta) = 3.08×10(-7); 0.88 (0.84-0.93)] and rs10930046 (Arg460His) [P(dom) = 1.16×10(-8); 0.70 (0.62-0.79)]. Both missense variants produced dramatic phenotypic changes in apoptosis and inflammation-related gene expression. We experimentally validated function of the intronic SNP by DNA electrophoresis, protein identification, and in vitro protein binding assays. DNA carrying the intronic risk allele rs13023380 showed reduced binding efficiency to a cellular protein complex including nucleolin and lupus autoantigen Ku70/80, and showed reduced transcriptional activity in vivo. Thus, in SLE patients, genetic susceptibility could create a biochemical imbalance that dysregulates nucleolin, Ku70/80, or other nucleic acid regulatory proteins. This could promote antibody hypermutation and auto-antibody generation, further destabilizing the cellular network. Together with molecular modeling, our results establish a distinct role for IFIH1 in apoptosis, inflammation, and autoantibody production, and explain the molecular basis of these three risk alleles for SLE pathogenesis., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2013
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25. Genome-wide linkage and copy number variation analysis reveals 710 kb duplication on chromosome 1p31.3 responsible for autosomal dominant omphalocele.
- Author
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Radhakrishna U, Nath SK, McElreavey K, Ratnamala U, Sun C, Maiti AK, Gagnebin M, Béna F, Newkirk HL, Sharp AJ, Everman DB, Murray JC, Schwartz CE, Antonarakis SE, and Butler MG
- Subjects
- Comparative Genomic Hybridization, Female, Genome-Wide Association Study, Haplotypes, Humans, Lod Score, Male, Pedigree, Polymorphism, Single Nucleotide, Chromosome Duplication, Chromosomes, Human, Pair 1, DNA Copy Number Variations, Genes, Dominant, Genetic Linkage, Hernia, Umbilical genetics
- Abstract
Background: Omphalocele is a congenital birth defect characterised by the presence of internal organs located outside of the ventral abdominal wall. The purpose of this study was to identify the underlying genetic mechanisms of a large autosomal dominant Caucasian family with omphalocele., Methods and Findings: A genetic linkage study was conducted in a large family with an autosomal dominant transmission of an omphalocele using a genome-wide single nucleotide polymorphism (SNP) array. The analysis revealed significant evidence of linkage (non-parametric NPL = 6.93, p=0.0001; parametric logarithm of odds (LOD) = 2.70 under a fully penetrant dominant model) at chromosome band 1p31.3. Haplotype analysis narrowed the locus to a 2.74 Mb region between markers rs2886770 (63014807 bp) and rs1343981 (65757349 bp). Molecular characterisation of this interval using array comparative genomic hybridisation followed by quantitative microsphere hybridisation analysis revealed a 710 kb duplication located at 63.5-64.2 Mb. All affected individuals who had an omphalocele and shared the haplotype were positive for this duplicated region, while the duplication was absent from all normal individuals of this family. Multipoint linkage analysis using the duplication as a marker yielded a maximum LOD score of 3.2 at 1p31.3 under a dominant model. The 710 kb duplication at 1p31.3 band contains seven known genes including FOXD3, ALG6, ITGB3BP, KIAA1799, DLEU2L, PGM1, and the proximal portion of ROR1. Importantly, this duplication is absent from the database of genomic variants., Conclusions: The present study suggests that development of an omphalocele in this family is controlled by overexpression of one or more genes in the duplicated region. To the authors' knowledge, this is the first reported association of an inherited omphalocele condition with a chromosomal rearrangement.
- Published
- 2012
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26. Non-synonymous variant (Gly307Ser) in CD226 is associated with susceptibility to multiple autoimmune diseases.
- Author
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Maiti AK, Kim-Howard X, Viswanathan P, Guillén L, Qian X, Rojas-Villarraga A, Sun C, Cañas C, Tobón GJ, Matsuda K, Shen N, Cherñavsky AC, Anaya JM, and Nath SK
- Subjects
- Argentina, Asian People genetics, Case-Control Studies, Colombia, Gene Frequency, Genotype, Humans, Statistics as Topic, White People genetics, T Lineage-Specific Activation Antigen 1, Antigens, Differentiation, T-Lymphocyte genetics, Autoimmune Diseases genetics, Genetic Predisposition to Disease genetics
- Abstract
Objectives: Recently, a non-synonymous (Gly307Ser) variant, rs763361, in the CD226 gene was shown to be associated with multiple autoimmune diseases (ADs) in European Caucasian populations. However, shared autoimmunity with CD226 has not been evaluated in non-European populations. The aim of the present study is to assess the association of this single nucleotide polymorphism (SNP) with ADs in non-European populations., Methods: To replicate this association in non-European populations, we evaluated case-control association between rs763361 and coeliac disease (CED) samples from Argentina; SLE, RA, type-1 diabetes (T1D) and primary SS (pSS) from Colombia; and SLE samples from China and Japan. We genotyped rs763361 and evaluated its genetic association with multiple ADs, using chi(2)-test. For each association, odds ratio (OR) and 95% CI were calculated., Results: We show that rs763361 is significantly associated with Argentinean CED (P = 0.0009, OR = 1.60). We also observed a trend of possible association with Chinese SLE (P = 0.01, OR = 1.19), RA (P = 0.047, OR = 1.25), SLE (P = 0.0899, OR = 1.24) and pSS (P = 0.09, OR = 1.33) in Colombians. Meta-analyses for SLE (using our three populations) and T1D (our population and three published populations) yielded significant association with rs763361, P = 0.009 (OR = 1.16) and P = 1.1.46 x 10(-9) (OR = 1.14), respectively., Conclusions: Our results demonstrate that the coding variant rs763361 in CD226 gene is associated with multiple ADs in non-European populations.
- Published
- 2010
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27. Gene network analysis of oxidative stress-mediated drug sensitivity in resistant ovarian carcinoma cells.
- Author
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Maiti AK
- Subjects
- Apoptosis drug effects, Cell Line, Tumor, Female, Humans, Oligonucleotide Array Sequence Analysis, Oxidative Stress drug effects, Reactive Oxygen Species metabolism, Rho Guanine Nucleotide Exchange Factors, Signal Transduction, Carcinoma drug therapy, Chlorambucil therapeutic use, DNA-Activated Protein Kinase physiology, Drug Resistance, Neoplasm genetics, Guanine Nucleotide Exchange Factors physiology, Nuclear Proteins physiology, Ovarian Neoplasms drug therapy, Oxidative Stress genetics, Tumor Suppressor Protein p53 genetics
- Abstract
Drug resistance in cancer cells involves complex molecular mechanisms and ovarian carcinoma cells become resistant to chlorambucil (Cbl) after continuous treatment. This drug- and ionizing radiation-resistant cells have lower level of endogenous ROS (reactive oxygen species) compared with sensitive cells. Elevation of the cellular ROS level by exogenous ROS generation increases the sensitivity of Cbl to resistant cells. In contrast, antioxidants prevent the sensitization of resistant cells to Cbl by H(2)O(2), COS (chronic oxidative stress) or NOO(-). The molecular mechanism of drug sensitivity with COS has been investigated by microarray gene expressions followed by gene network analysis and it reveals that a cdc42/rac1 guanine exchange factor, ARHGEF6, with p53 and DNA-Pkc (PRKDC) is central to induce apoptosis in Cbl(cos) (Cbl with COS) cells. mRNA and protein levels of major gene network pathway differ significantly in Cbl(cos) cells than in Cbl-treated cells. Moreover, DNA-PKc physically interacts with ARHGEF6 and p53 mostly in the nucleus of Cbl-treated cells, whereas in Cbl(cos)-treated cells, its interactions are mostly in the cytoplasm. These results suggest that low doses of Cbl and very low doses of COS together kill Cbl-resistant ovarian carcinoma cells and ARHGEF6 signaling may have an instrumental role in induction of apoptosis in Cbl(cos) cells.
- Published
- 2010
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28. Regulatory role of human AP-endonuclease (APE1/Ref-1) in YB-1-mediated activation of the multidrug resistance gene MDR1.
- Author
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Chattopadhyay R, Das S, Maiti AK, Boldogh I, Xie J, Hazra TK, Kohno K, Mitra S, and Bhakat KK
- Subjects
- Acetylation, Cell Line, Tumor, Cisplatin pharmacology, DNA-(Apurinic or Apyrimidinic Site) Lyase metabolism, Doxorubicin pharmacology, Gene Expression Regulation, Neoplastic, Humans, Up-Regulation, ATP Binding Cassette Transporter, Subfamily B, Member 1 metabolism, DNA-(Apurinic or Apyrimidinic Site) Lyase physiology, Y-Box-Binding Protein 1 metabolism
- Abstract
Human AP-endonuclease (APE1/Ref-1), a central enzyme involved in the repair of oxidative base damage and DNA strand breaks, has a second activity as a transcriptional regulator that binds to several trans-acting factors. APE1 overexpression is often observed in tumor cells and confers resistance to various anticancer drugs; its downregulation sensitizes tumor cells to such agents. Because the involvement of APE1 in repairing the DNA damage induced by many of these drugs is unlikely, drug resistance may be linked to APE1's transcriptional regulatory function. Here, we show that APE1, preferably in the acetylated form, stably interacts with Y-box-binding protein 1 (YB-1) and enhances its binding to the Y-box element, leading to the activation of the multidrug resistance gene MDR1. The enhanced MDR1 level due to the ectopic expression of wild-type APE1 but not of its nonacetylable mutant underscores the importance of APE1's acetylation in its coactivator function. APE1 downregulation sensitizes MDR1-overexpressing tumor cells to cisplatin or doxorubicin, showing APE1's critical role in YB-1-mediated gene expression and, thus, drug resistance in tumor cells. A systematic increase in both APE1 and MDR1 expression was observed in non-small-cell lung cancer tissue samples. Thus, our study has established the novel role of the acetylation-mediated transcriptional regulatory function of APE1, making it a potential target for the drug sensitization of tumor cells.
- Published
- 2008
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29. Epidermal growth factor receptor and proliferating cell nuclear antigen in astrocytomas.
- Author
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Maiti AK, Ghosh K, Chatterjee U, Chakrobarti S, Chatterjee S, and Basu S
- Subjects
- Adult, Aged, Astrocytoma genetics, Brain Neoplasms genetics, ErbB Receptors genetics, Female, Humans, Immunohistochemistry, Male, Middle Aged, Proliferating Cell Nuclear Antigen genetics, Astrocytoma metabolism, Brain Neoplasms metabolism, ErbB Receptors metabolism, Proliferating Cell Nuclear Antigen metabolism
- Abstract
Aims: The involvement of various growth factors, growth factor receptors and proliferative markers in the molecular pathogenesis of astrocytic neoplasms are being studied extensively. Epidermal Growth Factor Receptor (EGFR) gene overexpression occurs in nearly 50% of cases of glioblastoma. Since EGFR and proliferating cell nuclear antigen (PCNA) are involved in mitogenic signal transduction and cellular proliferation pathway, we have studied the correlation between the expression of EGFR and PCNA labeling index in astrocytic tumors., Materials and Methods: We investigated the immunohistochemical expression of EGFR and PCNA using the appropriate monoclonal antibodies in 40 cases of astrocytic tumors of which 21 cases were glioblastoma, eight cases were Grade III or anaplastic astrocytomas and six cases were Grade II or diffuse astrocytomas and five cases were Grade I or pilocytic astrocytomas., Results: Both the EGFR expression and PCNA labeling index increase with increasing grades of astrocytomas with a significantly high percentage of cells showing positive staining for both EGFR and PCNA in GBM and Grade III astrocytomas compared to Grade II astrocytomas. The expression levels of both EGFR and PCNA were low in Grade I or pilocytic astrocytomas., Conclusions: A significant correlation was found between EGFR overexpression and PCNA labeling index in Grade III and Grade II astrocytomas and glioblastoma. These suggest that the tumor proliferation, at least in higher grades of astrocytomas is dependent in some measure on EGF and EGFR-related signaling pathways.
- Published
- 2008
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30. Mutations in the DNAH11 (axonemal heavy chain dynein type 11) gene cause one form of situs inversus totalis and most likely primary ciliary dyskinesia.
- Author
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Bartoloni L, Blouin JL, Pan Y, Gehrig C, Maiti AK, Scamuffa N, Rossier C, Jorissen M, Armengot M, Meeks M, Mitchison HM, Chung EM, Delozier-Blanchet CD, Craigen WJ, and Antonarakis SE
- Subjects
- Axonemal Dyneins, Base Sequence, Chromosome Mapping, DNA, Complementary, Humans, Kartagener Syndrome genetics, Male, Molecular Sequence Data, Situs Inversus genetics, Chromosomes, Human, Pair 7, Dyneins genetics, Kartagener Syndrome enzymology, Mutation, Missense, Situs Inversus enzymology
- Abstract
Primary ciliary dyskinesia (PCD; MIM 242650) is an autosomal recessive disorder of ciliary dysfunction with extensive genetic heterogeneity. PCD is characterized by bronchiectasis and upper respiratory tract infections, and half of the patients with PCD have situs inversus (Kartagener syndrome). We characterized the transcript and the genomic organization of the axonemal heavy chain dynein type 11 (DNAH11) gene, the human homologue of murine Dnah11 or lrd, which is mutated in the iv/iv mouse model with situs inversus. To assess the role of DNAH11, which maps on chromosome 7p21, we searched for mutations in the 82 exons of this gene in a patient with situs inversus totalis, and probable Kartagener syndrome associated with paternal uniparental disomy of chromosome 7 (patUPD7). We identified a homozygous nonsense mutation (R2852X) in the DNAH11 gene. This patient is remarkable because he is also homozygous for the F508del allele of the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Sequence analysis of the DNAH11 gene in an additional 6 selected PCD sibships that shared DNAH11 alleles revealed polymorphic variants and an R3004Q substitution in a conserved position that might be pathogenic. We conclude that mutations in the coding region of DNAH11 account for situs inversus totalis and probably a minority of cases of PCD.
- Published
- 2002
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31. Identification, genomic organization, chromosomal mapping and mutation analysis of the human INV gene, the ortholog of a murine gene implicated in left-right axis development and biliary atresia.
- Author
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Schön P, Tsuchiya K, Lenoir D, Mochizuki T, Guichard C, Takai S, Maiti AK, Nihei H, Weil J, Yokoyama T, and Bouvagnet P
- Subjects
- Amino Acid Sequence, Animals, Base Sequence, Brain embryology, Brain Chemistry, DNA Mutational Analysis, DNA Primers, Embryonic and Fetal Development, Female, Fetus, Functional Laterality genetics, Gene Library, Humans, Male, Mice, Molecular Sequence Data, Pedigree, Proteins, Reverse Transcriptase Polymerase Chain Reaction, Sequence Alignment, Sequence Homology, Amino Acid, Biliary Atresia genetics, Chromosome Mapping, Transcription Factors
- Abstract
Determination of left-right axis is a precocious embryonic event, and all phenotypic anomalies resulting from disruption of the normal lateralization process are collectively referred to as the lateralization defect. A transgenic mouse with lateralization defect and hepatic, kidney, and pancreatic anomalies has resulted from disruption of the inv gene by insertion of a transgene. The human ortholog is thus a good candidate for lateralization defect in humans, in particular in cases with associated hepatic anomalies. Here, we have identified, mapped, and characterized the INV human gene and screened a series of heterotaxic patients (with or without biliary anomalies) for mutation in this gene. In a German family of Turkish origin, we have found that all available affected and unaffected individuals are heterozygous for a mutation in the splicing donor site of intron 12 in the INV gene resulting in two different aberrant splicing isoforms. This can be explained either by a randomization of lateralization defects or, as suggested earlier, di- or trigenic inheritance, although we have been unable to detect, in this family, a mutation in genes known to be involved in the human lateralization defect ( LEFTY1, LEFTY2, ACVR2B, NODAL, ZIC3, and CFC1). In contrast to the mouse, the affected individuals have no biliary anomalies, and the absence of mutation in a series of seven cases with lateralization defect and biliary anomalies demonstrates that INV is not frequently involved in such a phenotype in humans.
- Published
- 2002
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32. Axonemal beta heavy chain dynein DNAH9: cDNA sequence, genomic structure, and investigation of its role in primary ciliary dyskinesia.
- Author
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Bartoloni L, Blouin JL, Maiti AK, Sainsbury A, Rossier C, Gehrig C, She JX, Marron MP, Lander ES, Meeks M, Chung E, Armengot M, Jorissen M, Scott HS, Delozier-Blanchet CD, Gardiner RM, and Antonarakis SE
- Subjects
- Adenosine Triphosphate metabolism, Amino Acid Motifs, Amino Acid Sequence, Axonemal Dyneins, Binding Sites, Cloning, Molecular, DNA Mutational Analysis, DNA, Complementary, Dyneins chemistry, Dyneins physiology, Exons, Female, Genetic Heterogeneity, Guanosine Triphosphate metabolism, Humans, Introns, Leucine Zippers, Male, Microtubules metabolism, Molecular Sequence Data, Phenotype, Phosphorylation, Protein Structure, Tertiary, Sequence Alignment, Cilia chemistry, Ciliary Motility Disorders genetics, Dyneins genetics, Microtubules chemistry
- Abstract
Dyneins are multisubunit protein complexes that couple ATPase activity with conformational changes. They are involved in the cytoplasmatic movement of organelles (cytoplasmic dyneins) and the bending of cilia and flagella (axonemal dyneins). Here we present the first complete cDNA and genomic sequences of a human axonemal dynein beta heavy chain gene, DNAH9, which maps to 17p12. The 14-kb-long cDNA is divided into 69 exons spread over 390 kb. The cDNA sequence of DNAH9 was determined using a combination of methods including 5' rapid amplification of cDNA ends, RT-PCR, and cDNA library screening. RT-PCR using nasal epithelium and testis RNA revealed several alternatively spliced transcripts. The genomic structure was determined using three overlapping BACs sequenced by the Whitehead Institute/MIT Center for Genome Research. The predicted protein, of 4486 amino acids, is highly homologous to sea urchin axonemal beta heavy chain dyneins (67% identity). It consists of an N-terminal stem and a globular C-terminus containing the four P-loops that constitute the motor domain. Lack of proper ciliary and flagellar movement characterizes primary ciliary dyskinesia (PCD), a genetically heterogeneous autosomal recessive disorder with respiratory tract infections, bronchiectasis, male subfertility, and, in 50% of cases, situs inversus (Kartagener syndrome, KS). Dyneins are excellent candidate genes for PCD and KS because in over 50% of cases the ultrastructural defects of cilia are related to the dynein complex. Genotype analysis was performed in 31 PCD families with two or more affected siblings using a highly informative dinucleotide polymorphism located in intron 26 of DNAH9. Two families with concordant inheritance of DNAH9 alleles in affected individuals were observed. A mutation search was performed in these two "candidate families," but only polymorphic variants were found. In the absence of pathogenic mutations, the DNAH9 gene has been excluded as being responsible for autosomal recessive PCD in these families., (Copyright 2001 Academic Press.)
- Published
- 2001
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33. Isolation, in silico characterization and chromosomal localization of a group of cDNAs from ciliated epithelial cells after in vitro ciliogenesis.
- Author
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Maiti AK, Jorissen M, and Bouvagnet P
- Subjects
- Cells, Cultured, Chromosome Mapping, Cilia physiology, DNA, Complementary genetics, DNA, Mitochondrial genetics, Databases, Nucleic Acid, Expressed Sequence Tags, Humans, Nasal Mucosa cytology, Epithelial Cells metabolism, Nasal Mucosa metabolism
- Abstract
Background: Immotile cilia syndrome (ICS) or primary ciliary dyskinesia (PCD) is an autosomal recessive disorder in humans in which the beating of cilia and sperm flagella is impaired. Ciliated epithelial cell linings are present in many tissues. To understand ciliary assembly and motility, it is important to isolate those genes involved in the process., Results: Total RNA was isolated from cultured ciliated nasal epithelial cells after in vitro ciliogenesis and expressed sequenced tags (ESTs) were generated. The functions and locations of 63 of these ESTs were derived by BLAST from two public databases. These ESTs are grouped into various classes. One group has high homology not only with the mitochondrial genome but also with one or more chromosomal DNAs, suggesting that very similar genes, or genes with very similar domains, are expressed from both mitochondrial and nuclear DNA. A second class comprises genes with complete homology with part of a known gene, suggesting that they are the same genes. A third group has partial homology with domains of known genes. A fourth group, constituting 33% of the ESTs characterized, has no significant homology with any gene or EST in the database., Conclusions: We have shown that sufficient information about the location of ESTs could be derived electronically from the recently completed human genome sequences. This strategy of EST localization should be significantly useful for mapping and identification of new genes in the forthcoming human genome sequences with the vast number of ESTs in the dbEST database.
- Published
- 2001
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34. Poly purine.pyrimidine sequences upstream of the beta-galactosidase gene affect gene expression in Saccharomyces cerevisiae.
- Author
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Maiti AK and Brahmachari SK
- Abstract
Background: Poly purine.pyrimidine sequences have the potential to adopt intramolecular triplex structures and are overrepresented upstream of genes in eukaryotes. These sequences may regulate gene expression by modulating the interaction of transcription factors with DNA sequences upstream of genes., Results: A poly purine.pyrimidine sequence with the potential to adopt an intramolecular triplex DNA structure was designed. The sequence was inserted within a nucleosome positioned upstream of the beta-galactosidase gene in yeast, Saccharomyces cerevisiae, between the cycl promoter and gal 10 Upstream Activating Sequences (UASg). Upon derepression with galactose, beta-galactosidase gene expression is reduced 12-fold in cells carrying single copy poly purine.pyrimidine sequences. This reduction in expression is correlated with reduced transcription. Furthermore, we show that plasmids carrying a poly purine.pyrimidine sequence are not specifically lost from yeast cells., Conclusion: We propose that a poly purine.pyrimidine sequence upstream of a gene affects transcription. Plasmids carrying this sequence are not specifically lost from cells and thus no additional effort is needed for the replication of these sequences in eukaryotic cells.
- Published
- 2001
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35. Identification, tissue specific expression, and chromosomal localisation of several human dynein heavy chain genes.
- Author
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Maiti AK, Mattéi MG, Jorissen M, Volz A, Zeigler A, and Bouvagnet P
- Subjects
- Amino Acid Sequence, Cells, Cultured, Cloning, Molecular, DNA, Complementary analysis, Dyneins biosynthesis, Dyneins classification, Humans, In Situ Hybridization, Fluorescence, Karyotyping, Molecular Sequence Data, Phylogeny, Pseudogenes, Reverse Transcriptase Polymerase Chain Reaction, Sequence Homology, Amino Acid, Tissue Distribution, Chromosome Mapping, Dyneins genetics
- Abstract
Sliding between adjacent microtubules within the axonema gives rise to the motility of cilia and flagella. The driving force is produced by dynein complexes which are mainly composed of the axonemal dynein heavy chains. We used cells of human respiratory epithelium after in vitro ciliogenesis to clone cDNA fragments of nine dynein heavy chain genes, one of which had never been identified before. Dynein heavy chains are highly conserved from protozoa to human and the evolutionary ancestry of these dynein heavy chain cDNA fragments was deduced by phylogenetic analysis. These dynein heavy chain cDNAs are highly transcribed in human tissues containing axonema such as trachea, testis and brain, but not in adult heart or placenta. PAC clones containing dynein heavy chains were obtained and used to determine by FISH their chromosomal position in the human genome. They were mapped to 2p12-p11, 2q33, 3p21.2-p21.1, 13q14, 16p12 and 17p12. The chromosomal assignment of these dynein heavy chain genes which was confirmed by GeneBridge 4 radiation hybrid screening, will be extremely useful for linkage analysis efforts in patients with primary ciliary dyskinesia (PCD).
- Published
- 2000
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36. Metabolism of gamma-hexachlorocyclohexane by Arthrobacter citreus strain BI-100: Identification of metabolites.
- Author
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Datta J, Maiti AK, Modak DP, Chakrabartty PK, Bhattacharyya P, and Ray PK
- Abstract
Growth characteristics of the aerobic bacterial strain Arthrobacter citreus BI-100 in mineral salts medium with gamma-hexachlorocyclohexane (gamma-HCH) as the sole source of carbon and degradation of gamma-HCH by the strain are reported. The highest yield of the bacteria is observed at a gamma-HCH concentration of 100 mg/L. At this concentration, the bacteria entered the exponential phase of growth without any lag. At 8 h of growth, no residual HCH, but its metabolites, was detectable in the medium. The bacterium attained its stationary phase at 48 h and at 72 h; no metabolite of gamma-HCH could be detected by gas chromatography. Six metabolic intermediates of gamma-HCH produced by A. citreus BI-100 at different periods of growth were characterized by using gas chromatography-mass spectrometry and high-performance liquid chromatography, which furnished evidence for the presence of gamma-1,3,4,5,6-pentachlorocyclohexene, tetrachlorocyclohexene, trichlorocyclohexa-diene, 2-chlorophenol, phenol, and catechol, among others.
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- 2000
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37. Polypurine/polypyrimidine sequences as cis-acting transcriptional regulators.
- Author
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Brahmachari SK, Sarkar PS, Raghavan S, Narayan M, and Maiti AK
- Subjects
- Animals, Base Sequence, COS Cells, Chromosomes, Fungal, Cloning, Molecular, DNA, Down-Regulation, Escherichia coli genetics, Genetic Vectors, Lac Operon, Molecular Sequence Data, Purines metabolism, Pyrimidines metabolism, Transcription, Genetic
- Abstract
Genome sequence information has generated increasing evidence for the claim that repetitive DNA sequences present within and around genes could play a important role in the regulation of gene expression. Polypurine/polypyrimidine sequences [poly(Pu/Py)] have been observed in the vicinity of promoters and within the transcribed regions of many genes. To understand whether such sequences influence the level of gene expression, we constructed several prokaryotic and eukaryotic expression vectors incorporating poly(Pu/Py) repeats both within and upstream of a reporter gene, lacZ (encoding beta-galactosidase), and studied its expression in vivo. We find that, in contrast to the situation in Escherichia coli, the presence of poly(Pu/Py) sequences within the gene does not significantly inhibit gene expression in mammalian cells. On the other hand, the presence of such sequences upstream of lacZ leads to a several-fold reduction of gene expression in mammalian cells. Similar down-regulation was observed when a structural cassette containing poly(Pu/Py) sequences upstream of lacZ was integrated into yeast chromosome V. Sequence analysis of the nine totally sequenced yeast chromosomes shows that a large number of such sequences occur upstream of ORFs. On the basis of our experimental results and DNA sequence analysis, we propose that these sequences can function as cis-acting transcriptional regulators.
- Published
- 1997
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38. Vagal tone and the physiological regulation of emotion.
- Author
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Porges SW, Doussard-Roosevelt JA, and Maiti AK
- Subjects
- Affect physiology, Autonomic Nervous System physiology, Brain physiology, Functional Laterality physiology, Humans, Emotions physiology, Vagus Nerve physiology
- Abstract
On the basis of current knowledge of neuroanatomy and our previous research with cardiac vagal tone, we have proposed the vagal circuit of emotion regulation. The vagal circuit of emotion regulation incorporates lateral brain function with the regulation of the peripheral autonomic nervous system in the expression of emotion. The vagus and the vagal circuit do not function independently of other neurophysiological and neuroendocrine systems. Research on brain activity (see Dawson, in this volume; Fox, in this volume) and research on adrenocortical activity (see Stansbury & Gunnar, in this volume) demonstrate that EEG and cortisol are related to emotion states and to individual differences similar to those that we have investigated. The vagal circuit emphasizes not only the vagus but also the lateralization of specific brain structures in emotion regulation. The emphasis of the vagal circuit on right-brain-stem structures stimulates several testable hypotheses regarding the function of specific structures in the right brain in emotion regulation. These speculations are consistent with other reports (see Dawson, in this volume; Fox, in this volume) describing asymmetrical EEG activity during expressed emotions. Moreover, the vagal circuit does not exist independently of the brain structures and peptide systems regulating cortisol (see Stansbury & Gunnar, in this volume). Areas in the brain stem regulating vagal activity are also sensitive to the peptides that regulate cortisol (e.g., vasopressin and corticotropin-releasing hormone). In this essay, we have provided information regarding the relation between vagal tone and emotion regulation. A review of research indicates that baseline levels of cardiac vagal tone and vagal tone reactivity abilities are associated with behavioral measures of reactivity, the expression of emotion, and self-regulation skills. Thus, we propose that cardiac vagal tone can serve as an index of emotion regulation. Historically, the vagus and other components of the parasympathetic nervous system have not been incorporated in theories of emotion. Recent developments in methodology have enabled us to define and accurately quantify cardiac vagal tone. Theories relating the parasympathetic nervous system to the expression and regulation of emotion are now being tested in several laboratories.
- Published
- 1994
39. Influences of vestibulo-cerebellum on kindling in the cat.
- Author
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Guha D and Maiti AK
- Subjects
- Animals, Cats, Electric Stimulation, Female, Male, Rotation, Cerebellum physiology, Kindling, Neurologic physiology, Vestibule, Labyrinth physiology
- Abstract
The development of amygdaloid kindling was assessed under conditions of pharmacological depression of the nodular areas of vestibulocerebellum and also following vestibular stimulation in chronically prepared cats. The results demonstrated that a single intra-nodular micro-injection of procaine hydrochlorides could significantly facilitate such epileptogenesis for at least several days. The number of kindling trials required to reach the first generalized convulsions was significantly increased by natural vestibular stimulation in comparison with control kindled animals. The intensity of fit, development of amygdaloid seizures and the convulsions were reduced markedly within a week by pre-conditioning the kindled animals with daily vestibular stimulation for 15-30 min. In addition, analysis of the behaviour of sleep-wake cycle indicated a significant increase in total sleep time and in the percentage of rapid eye movement (REM) sleep. These findings suggest that the natural rotational vestibular stimulation may result in a durable modification of brain function through development of enduring focal sensitization of catecholamine-mediated inhibitory mechanisms, reflecting the tonic inhibitory influences of the vestibulo-cerebellum in regulating the development and attenuation of epileptic states.
- Published
- 1989
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