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Background: While exercise effects on the immune system have received increasing attention in recent years, it remains unclear to what extent gender and fluctuations in sex hormones during menstrual cycle influence immunological responses to exercise., Methods: We investigated mRNA changes induced through exhaustive exercise (half-marathon; pre-exercise and post-exercise [30 min, 3 h, 24 h] on whole blood cultures ± lipopolysaccharide [LPS] [1 h]) with a specific focus on sex differences (men vs women in luteal phase) as an extension of our previous study., Results: Inflammation related signaling pathways, TLRs, cytosolic DNA sensing and RIG-I like receptors were differentially activated between sexes in LPS-stimulated cultures. Genes differentially regulated between sexes included TNIP-1, TNIP-3, IL-6, HIVEP1, CXCL3, CCR3, IL-8, and CD69, revealing a bias towards less anti-inflammatory gene regulation in women compared to men. In addition, several genes relevant to brain function (KMO, DDIT4, VEGFA, IGF1R, IGF2R, and FGD4) showed differential activation between sexes. Some of these genes (e.g., KMO in women, DDIT4 in both sexes) potentially constitute neuroprotective mechanisms., Conclusions: These data reveal that the exercise-induced change in gene expression might be gender and menstrual cycle phase dependent.

The common age-related neurodegeneration of Parkinson's disease can result from dominant causes like increased dosage of vesicle-associated alpha-synuclein (SNCA) or recessive causes like deficiency of mitophagy factor PINK1. Interactions between these triggers and their convergence onto shared pathways are crucial, but currently conflicting evidence exists. Here, we crossed previously characterized mice with A53T-SNCA overexpression and with Pink1 deletion to generate double mutants (DMs). We studied their lifespan and behavior, histological and molecular anomalies at late and early ages. DM animals showed potentiated phenotypes in comparison with both single mutants (SMs), with reduced survival and strongly reduced spontaneous movements from the age of 3 months onwards. In contrast to SMs, a quarter of DM animals manifested progressive paralysis at ages >1 year and exhibited protein aggregates immunopositive for pSer129-SNCA, p62 and ubiquitin in spinal cord and basal brain. Brain proteome quantifications of ubiquitination sites documented altered degradation of SNCA and the DNA-damage marker H2AX at the age of 18 months. Global brain transcriptome profiles and qPCR validation experiments identified many consistent transcriptional dysregulations already at the age of 6 weeks, which were absent from SMs. The observed downregulations for Dapk1, Dcaf17, Rab42 and the novel SNCA-marker Lect1 as well as the upregulations for Dctn5, Mrpl9, Tmem181a, Xaf1 and H2afx reflect changes in ubiquitination, mitochondrial/synaptic/microtubular/cell adhesion dynamics and DNA damage. Thus, our study confirmed that SNCA-triggered neurotoxicity is exacerbated by the absence of PINK1 and identified a novel molecular signature that is detectable early in the course of this double pathology., (© The Author 2014. Published by Oxford University Press.)

The slowdown, inhibition, or reversal of age-related decline (as a composite of disease, dysfunction, and, ultimately, death) by diet or natural compounds can be defined as dietary geroprotection. While there is no single reliable biomarker to judge the effects of dietary geroprotection, biomarker signatures based on omics (epigenetics, gene expression, microbiome composition) are promising candidates. Recently, omic biomarkers started to supplement established clinical ones such as lipid profiles and inflammatory cytokines. In this review, we focus on human data. We first summarize the current take on genetic biomarkers based on epidemiological studies. However, most of the remaining biomarkers that we describe, whether omics-based or clinical, are related to intervention studies. Then, because of their promising potential in the context of dietary geroprotection, we focus on the effects of berry-based interventions, which up to now have been mostly described employing clinical markers. We provide an aggregation and tabulation of all the recent systematic reviews and meta-analyses that we could find related to this topic. Finally, we present evidence for the importance of the "nutribiography," that is, the influence that an individual's history of diet and natural compound consumption can have on the effects of dietary geroprotection. Supplemental data for this article is available online at https://doi.org/10.1080/10408398.2021.1975638 Supplemental data for this article is available online at https://doi.org/10.1080/10408398.2021.1975638 [ABSTRACT FROM AUTHOR]

The neurodegenerative disease glaucoma is one of the leading causes of blindness in the world. Glaucoma is characterized by progressive visual field loss caused by retinal ganglion cell (RGC) death. Both surgical glaucoma treatments and medications are available, however, they only halt glaucoma progression and are unable to reverse damage. Furthermore, many patients do not respond well to treatments. It is therefore important to better understand the mechanisms involved in glaucoma pathogenesis. Patients with Axenfeld-Rieger syndrome (ARS) offer important insight into glaucoma progression. ARS patients are at 50% risk of developing early onset glaucoma and respond poorly to treatments, even when surgical treatments are combined with medications. Mutations in the transcription factor FOXC1 cause ARS. Alterations in FOXC1 levels cause ocular malformations and disrupt stress response in ocular tissues, thereby contributing to glaucoma progression. In this study, using biochemical and molecular techniques, we show that FOXC1 regulates the expression of RAB3GAP1, RAB3GAP2 and SNAP25, three genes with central roles in both exocytosis and endocytosis, responsible for extracellular trafficking. FOXC1 positively regulates RAB3GAP1 and RAB3GAP2, while either increase or decrease in FOXC1 levels beyond its normal range results in decreased SNAP25. In addition, we found that FOXC1 regulation of RAB3GAP1, RAB3GAP2 and SNAP25 affects secretion of Myocilin (MYOC), a protein associated with juvenile onset glaucoma and steroid-induced glaucoma. The present work reveals that FOXC1 is an important regulator of exocytosis and establishes a new link between FOXC1 and MYOC-associated glaucoma. [ABSTRACT FROM AUTHOR]

Spinocerebellar ataxia type 2 (SCA2) is an autosomal dominantly inherited neurodegenerative disorder with preferential affection of Purkinje neurons, which are known as integrators of calcium currents. The expansion of a polyglutamine (polyQ) domain in the RNA-binding protein ataxin-2 (ATXN2) is responsible for this disease, but the causal roles of deficient ATXN2 functions versus aggregation toxicity are still under debate. Here, we studied mouse mutants with Atxn2 knockout (KO) regarding their cerebellar global transcriptome by microarray and RT-qPCR, in comparison with data from Atxn2-CAG42-knock-in (KIN) mouse cerebellum. Global expression downregulations involved lipid and growth signaling pathways in good agreement with previous data. As a novel effect, downregulations of key factors in calcium homeostasis pathways (the transcription factor Rora, transporters Itpr1 and Atp2a2, as well as regulator Inpp5a) were observed in the KO cerebellum, and some of them also occurred subtly early in KIN cerebellum. The ITPR1 protein levels were depleted from soluble fractions of cerebellum in both mutants, but accumulated in its membrane-associated form only in the SCA2 model. Coimmunoprecipitation demonstrated no association of ITPR1 with Q42-expanded or with wild-type ATXN2. These findings provide evidence that the physiological functions and protein interactions of ATXN2 are relevant for calcium-mediated excitation of Purkinje cells as well as for ATXN2-triggered neurotoxicity. These insights may help to understand pathogenesis and tissue specificity in SCA2 and other polyQ ataxias like SCA1, where inositol regulation of calcium flux and RORalpha play a role. [ABSTRACT FROM AUTHOR]

Background: While exercise effects on the immune system have received increasing attention in recent years, it remains unclear to what extent gender and fluctuations in sex hormones during menstrual cycle influence immunological responses to exercise. Methods: We investigated mRNA changes induced through exhaustive exercise (half-marathon; pre-exercise and post-exercise [30 min, 3 h, 24 h] on whole blood cultures ± lipopolysaccharide [LPS] [1 h]) with a specific focus on sex differences (men vs women in luteal phase) as an extension of our previous study. Results: Inflammation related signaling pathways, TLRs, cytosolic DNA sensing and RIG-I like receptors were differentially activated between sexes in LPS-stimulated cultures. Genes differentially regulated between sexes included TNIP-1, TNIP-3, IL-6, HIVEP1, CXCL3, CCR3, IL-8, and CD69, revealing a bias towards less anti-inflammatory gene regulation in women compared to men. In addition, several genes relevant to brain function (KMO, DDIT4, VEGFA, IGF1R, IGF2R, and FGD4) showed differential activation between sexes. Some of these genes (e.g., KMO in women, DDIT4 in both sexes) potentially constitute neuroprotective mechanisms. Conclusions: These data reveal that the exercise-induced change in gene expression might be gender and menstrual cycle phase dependent. [ABSTRACT FROM AUTHOR]

Telomere length and cell function can be preserved by the human reverse transcriptase telomerase (hTERT), which synthesizes the new telomeric DNA from a RNA template, but is normally restricted to cells needing a high proliferative capacity, such as stem cells. Consequently, telomerase-based therapies to elongate short telomeres are developed, some of which have successfully reached the stage I in clinical trials. Telomerase is also permissive for tumorigenesis and 90% of all malignant tumors use telomerase to obtain immortality. Thus, reversal of telomerase upregulation in tumor cells is a potential strategy to treat cancer. Natural and small-molecule telomerase inhibitors, immunotherapeutic approaches, oligonucleotide inhibitors, and telomerase-directed gene therapy are useful treatment strategies. Telomerase ismore widely expressed than any other tumormarker. The low expression in normal tissues, together with the longer telomeres in normal stem cells versus cancer cells, provides some degree of specificity with low risk of toxicity. However, long term telomerase inhibition may elicit negative effects in highly-proliferative cells which need telomerase for survival, and it may interfere with telomere-independent physiological functions. Moreover, only a few hTERT molecules are required to overcome senescence in cancer cells, and telomerase inhibition requires proliferating cells over a sufficient number of population doublings to induce tumor suppressive senescence. These limitations may explain the moderate success rates in many clinical studies. Despite extensive studies, only one vaccine and one telomerase antagonist are routinely used in clinical work. For complete eradication of all subpopulations of cancer cells a simultaneous targeting of several mechanisms will likely be needed. Possible technical improvements have been proposed including the development of more specific inhibitors, methods to increase the efficacy of vaccination methods, and personalized approaches. Telomerase activation and cell rejuvenation is successfully used in regenerative medicine for tissue engineering and reconstructive surgery. However, there are also a number of pitfalls in the treatment with telomerase activating procedures for the whole organism and for longer periods of time. Extended cell lifespan may accumulate rare genetic and epigenetic aberrations that can contribute to malignant transformation. Therefore, novel vector systems have been developed for a 'mild' integration of telomerase into the host genome and loss of the vector in rapidly-proliferating cells. It is currently unclear if this technique can also be used in human beings to treat chronic diseases, such as atherosclerosis. [ABSTRACT FROM AUTHOR]

1,25-Dihydroxyvitamin D3 (1,25(OH)2D3) suppresses autoimmunity and inflammation; however, the mechanism of its action has not been fully understood. We sought in this study to determine whether the anti-immune/anti-inflammatory action of 1,25(OH)2D3 is in part mediated through an interplay between 1,25(OH)2D3 and toll-like receptor (TLR)7/8 signaling. 1,25(OH)2D3 treatment prior to and/or following experimental autoimmune encephalomyelitis (EAE) induction effectively reduced inflammatory cytokine expression in the spinal cord and ameliorated EAE. These effects were accompanied with a reduction in expression of several TLRs with the most profound effect observed for TLR8. The expression of TLR8 adaptor protein MyD88 was also significantly reduced by 1,25(OH)2D3. To determine the molecular mechanism by which 1,25(OH)2D3 suppresses EAE induction of TLR8 and inflammatory cytokine expression, we evaluated whether 1,25(OH)2D3 can directly inhibit TLR8 signaling and the resulting inflammatory responses in human THP-1 monocytes. 1,25(OH)2D3 treatment not only significantly reduced TLR8 expression but also the expression or activity of MyD88, IRF-4, IRF-7 and NF-kB in monocytes challenged with TLR8 ligands. TLR8 promoter-luciferase reporter assays indicated that 1,25(OH)2D3 decreases TLR8 mRNA level in part via inhibiting TLR8 gene transcription activity. As a result of inhibition on TLR8 signaling cascade at various stages, 1,25(OH)2D3 significantly diminished the TLR8 target gene expression (TNF-α and IL-1β). In summary, our novel findings suggest that TLR8 is a new target of 1,25(OH)2D3 and may mediate the anti-inflammatory action of 1,25(OH)2D3. Our findings also point to a destructive role of TLR8 in EAE and shed lights on pathogenesis of multiple sclerosis. [ABSTRACT FROM AUTHOR]

Purpose: The capacity of whole blood cultures to produce cytokines in response to endotoxin (LPS) was studied in athletes before, 30 min after, 3 h after and 24 h after a half-marathon run. Methods: Eight well trained men and 8 well trained women (6 of them in the late luteal phase of their cycle) participated. EDTA blood was incubated with or without LPS for 1 h, and cytokine concentration and gene expression were determined. To quantify LPS-dependent release on a per monocyte basis (LDR), the mean values of the difference (delta) between cytokine concentration in stimulated and unstimulated cultures, normalized to monocyte numbers, were calculated. Results: LDR of TNF-α was significantly reduced by exercise with identical kinetic in men and women. TNF-α mRNA expression was slightly down-regulated following exercise (P<0.05), but significantly so only in women. LDR of IL-6 was also reduced, but with a faster kinetic in women than in men. Similarly, 30 min post-exercise; LDR and spontaneous release of IL-1ra were significantly less in women than men. Concomitantly, IL- 1ra mRNA was significantly elevated in unstimulated and in stimulated cultures in men only. IL-10 and IL-10 mRNA were significantly induced 30 min following exercise in absence of any detectable LDR. Women showed significantly lower levels than men. LDR and spontaneous release of IL-8 was enhanced in men and TGF-β1 in women. A significant up-regulation was seen in unstimulated IL-8 mRNA for women and LPS-stimulated IL-8 mRNA expression for men following exercise. Conclusion: Altogether, LPS-dependent ex vivo cytokine release was strongly influenced by exercise and these changes could only in part be attributed to changes in messenger RNA. Results for IL-1ra, IL-6 and IL-10 pointed to a less pronounced anti-inflammatory response in women as compared with men. Our results also indicate an early production of IL-10 by peripheral blood cells in response to exercise [ABSTRACT FROM AUTHOR]

Subsequent to prolonged exhausting exercise a transient immunosuppression is often observed in athletes. This so-called "open window" results in a reduced resistance of the athletes to viral and bacterial infections after an exhaustive exercise bout. Concerning the effect of bacterial endotoxin contact after exhausting exercise in transplant recipients, who are innately immunosuppressed by their medication, no data exists at present. After performing 81 km cycling, including ascending more than 1800 m in altitude, peripheral blood from 10 male kidney transplant recipients and from 10 healthy controls matched for age and gender, was obtained. Simulating contact of the athletes with a pathogen post-exercise, the blood samples were incubated with Lipopolysaccharides (LPS). Thereafter, microarray analysis was performed. Microarray analysis revealed a markedly oppositional pattern of gene expression in transplant recipients compared with their controls after LPS incubation. Especially immune response genes were significantly over-represented in controls immediately after the exhaustive exercise bout with LPS stimulation, whereas numerous apoptotic genes were over-represented in transplant recipients. Merging our previous data with these recent findings it should be discussed if transplant recipients need to reduce their immunosuppressive medication before performing exhaustive exercise. [ABSTRACT FROM AUTHOR]

The presynaptic protein alpha-synuclein has received much attention because its gain-of-function is associated with Parkinson's disease. However, its physiological function is still poorly understood. We studied brain regions of knock-out mice at different ages with regard to consistent upregulations of the transcriptome and focused on glyoxalase I (GLO1). The microarray data were confirmed in qPCR, immunoblot, enzyme activity, and behavior analyses. GLO1 induction is a known protective cellular response to glucose stress, representing efforts to decrease toxic levels of methylglyoxal (MG), glyoxal and advanced glycation endproducts (AGEs). Mass spectrometry quantification demonstrated a ubiquitous increase in MG and fructosyl-lysine as consequences of glucose toxicity, and consistent enhancement of certain AGEs. Thus, GLO1 induction in KO brain seems insufficient to prevent AGE formation. In conclusion, the data demonstrate GLO1 expression and glycation damage to be induced by alpha-synuclein ablation. We propose that wild-type alpha-synuclein modulates brain glucose metabolism. [ABSTRACT FROM AUTHOR]

Background: The Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is present in at least 1 out of 4,500 female live births and is the second most common cause for primary amenorrhea. It is characterized by vaginal and uterine aplasia in an XX individual with normal secondary characteristics. It has long been considered a sporadic anomaly, but familial clustering occurs. Several candidate genes have been studied although no single factor has yet been identified. Cases of discordant monozygotic twins suggest that the involvement of epigenetic factors is more likely. Methods: Differences in gene expression and methylation patterns of uterine tissue between eight MRKH patients and eight controls were identified using whole-genome microarray analyses. Results obtained by expression and methylation arrays were confirmed by qRT-PCR and pyrosequencing. Results: We delineated 293 differentially expressed and 194 differentially methylated genes of which nine overlap in both groups. These nine genes are mainly embryologically relevant for the development of the female genital tract. Conclusion: Our study used, for the first time, a combined whole-genome expression and methylation approach to reveal the etiology of the MRKH syndrome. The findings suggest that either deficient estrogen receptors or the ectopic expression of certain HOXA genes might lead to abnormal development of the female reproductive tract. In utero exposure to endocrine disruptors or abnormally high maternal hormone levels might cause ectopic expression or anterior transformation of HOXA genes. It is, however, also possible that different factors influence the anti-Mullerian hormone promoter activity during embryological development causing regression of the Müllerian ducts. Thus, our data stimulate new research directions to decipher the pathogenic basis of MRKH syndrome. [ABSTRACT FROM AUTHOR]

Prolonged exhaustive exercise has a great impact on the immune system of athletes and leads to a transient weakening of the immune system. A host of studies has documented changes of immune parameters in peripheral blood following exercise. Concerning the effect of exhausting exercise in transplant recipients there is little knowledge at present. We analysed peripheral blood in healthy athletes and transplant recipients who participated in the "Euregio cycling tour 2009" before and immediately after they performed 81 km of cycling that included ascending more than 1800 m in altitude. A full blood count and an automated differential count as well as microarray analysis were performed before, immediately after, and one day after exercise in 10 male patients carrying a kidney transplant and in 10 controls matched in age and gender. Comparing the absolute increase in neutrophils in these two groups, we detected that the relative increase in neutrophils was significantly smaller in transplant recipients compared to their corresponding controls after exhausting exercise. While both groups were comparable in performance, microarray analysis revealed a markedly different pattern of gene expression in transplant recipients compared to their controls. From the 130 genes that were significantly upregulated in controls immediately after exercise, only 12 genes were also upregulated in transplant recipients. Sixty four different genes were upregulated in transplant recipients only. Our findings may be related to the immunosuppressive medication that the transplant recipients took and therefore it should also be discussed that regular exercise might reduce the need for immunosuppressive medication in transplant recipients. [ABSTRACT FROM AUTHOR]

Abstract: The pre-synaptic protein α-synuclein is a key player in the pathogenesis of Parkinson''s disease (PD). Misfolded α-synuclein protofibrils accumulate and serve as seed structures that cause numerous proteins in the cytoplasm of neuronal cells to aggregate into so-called Lewy bodies. Furthermore, both missense mutations and multiplications of the SNCA gene lead to autosomal dominant forms of familial PD. However, the exact biological role of α-synuclein in normal brains remains elusive. To gain more insight into the normal function of this protein, we evaluated changes in whole genome expression in dopaminergic neuroblastoma cells (SH-SY5Y) caused by reductions of 90% in α-synuclein RNA levels and of 59% in α-synuclein protein levels as a result of RNA interference. The expression of 361 genes was altered at least±1.5-fold by the RNA interference, with 82 up-regulated and 279 down-regulated. The differentially expressed gene products are involved in the regulation of transcription, cell cycle, protein degradation, apoptosis, neurogenesis, and lipid metabolism. To examine the influence of SNCA down-regulation by RNAi on apoptosis, we performed cell death assays using different stress triggers. The changes observed in the expression profile of dopaminergic neuronal cells following reduction of SNCA expression warrant studies to investigate the role of signaling cascades in familial and idiopathic PD. [Copyright &y& Elsevier]

The first step of the plastidial methylerythritol phosphate (MEP) pathway is catalyzed by two isoforms of 1-deoxy-d-xylulose 5-phosphate synthase (DXS1 and DXS2). In Medicago truncatula, MtDXS1 and MtDXS2 genes exhibit completely different expression patterns. Most prominently, colonization by arbuscular mycorrhizal (AM) fungi induces the accumulation of certain apocarotenoids (cyclohexenone and mycorradicin derivatives) correlated with the expression of MtDXS2 but not of MtDXS1. To prove a distinct function of DXS2, a selective RNAi approach on MtDXS2 expression was performed in transgenic hairy roots of M. truncatula. Repression of MtDXS2 consistently led to reduced transcript levels in mycorrhizal roots, and to a concomitant reduction of AM-induced apocarotenoid accumulation. The transcript levels of MtDXS1 remained unaltered in RNAi plants, and no phenotypical changes in non-AM plants were observed. Late stages of the AM symbiosis were adversely affected, but only upon strong repression with residual MtDXS2-1 transcript levels remaining below approximately 10%. This condition resulted in a strong decrease in the transcript levels of MtPT4, an AM-specific plant phosphate transporter gene, and in a multitude of other AM-induced plant marker genes, as shown by transcriptome analysis. This was accompanied by an increased proportion of degenerating and dead arbuscules at the expense of mature ones. The data reveal a requirement for DXS2-dependent MEP pathway-based isoprenoid products to sustain mycorrhizal functionality at later stages of the symbiosis. They further validate the concept of a distinct role for DXS2 in secondary metabolism, and offer a novel tool to selectively manipulate the levels of secondary isoprenoids by targeting their precursor supply. [ABSTRACT FROM AUTHOR]

Colonization of plant roots by symbiotic arbuscular mycorrhizal fungi frequently leads to the accumulation of several apocarotenoids. The corresponding carotenoid precursors originate from the plastidial 2-C-methyl-D-erythritol 4-phosphate pathway. We have cloned and characterized 1-deoxy-D-xylulose 5-phosphate reductoisomerase (DXR), catalyzing the first committed step of the pathway, from maize (Zea mays). Functional identification was accomplished by heterologous expression of sequences coding for the mature protein in Escherichia coil, DXR is up-regulated in maize roots during mycorrhization as shown at transcript and protein levels, but is also abundant in leaves and young seedlings. Inspection of sequenced genomes and expressed sequence tag (EST) databases argue for a single-copy DXR gene. Immunolocalization studies in mycorrhizal roots using affinity-purified antibodies revealed a DXR localization in plastids around the main symbiotic structures, the arbuscules. DXR protein accumulation is tightly correlated with arbuscule development. The highest level of DXR protein is reached around maturity and initial senescence of these structures. We further demonstrate the formation of a DXR-containing plastidial network around arbuscules, which is highly interconnected in the mature, functional state of the arbuscules. Our findings imply a functional role of a still unknown nature for the apocarotenoids or their respective carotenoid precursors in the arbuscular life cycle. [ABSTRACT FROM AUTHOR]

Systemic 1,25(OH)2D3 treatment ameliorating murine inflammatory bowel diseases (IBD) could not be applied to patients because of hypercalcemia. We tested the hypothesis that increasing 1,25(OH)2D3 synthesis locally by targeting delivery of the 1α-hydroxylase gene (CYP27B1) to the inflamed bowel would ameliorate IBD without causing hypercalcemia. Our targeting strategy is the use of CD11b+/Gr1+ monocytes as the cell vehicle and a macrophage-specific promoter (Mac1) to control CYP27B1 expression. The CD11b+/Gr1+ monocytes migrated initially to inflamed colon and some healthy tissues in dextran sulfate sodium (DSS) colitis mice; however, only the migration of monocytes to the inflamed colon was sustained. Adoptive transfer of Gr1+ monocytes did not cause hepatic injury. Infusion of Mac1-CYP27B1-modified monocytes increased body weight gain, survival, and colon length, and expedited mucosal regeneration. Expression of pathogenic Th17 and Th1 cytokines (interleukin (IL)-17a and interferon (IFN)-α) was decreased, while expression of protective Th2 cytokines (IL-5 and IL-13) was increased, by the treatment. This therapy also enhanced tight junction gene expression in the colon. No hypercalcemia occurred following this therapy. In conclusion, we have for the first time obtained proof-of-principle evidence for a novel monocyte-based adoptive CYP27B1 gene therapy using a mouse IBD model. This strategy could be developed into a novel therapy for IBD and other autoimmune diseases. [ABSTRACT FROM AUTHOR]

Highlight: [•] Some potentially important effects of exercise can only be detected in relation to pathogen stimulation. [ABSTRACT FROM AUTHOR]

Abstract: The class II transactivator (CIITA) is a key regulatory factor for MHC class II expression. Here, we demonstrate that PKCδ plays an important role in regulating IFN-γ-inducible CIITA gene expression in macrophages. Inhibition of PKCδ by either a PKCδ inhibitor or a dominant negative (DN) mutant form of PKCδ led to down-regulation of CIITA expression. The decrease in CIITA expression by PKCδ inhibition was in part due to the reduced recruitment of serine 727-phosphorylated Stat1 and histone acetyltransferases to the CIITA promoter. As a result, IFN-γ induced histone acetylation at the CIITA promoter is also compromised. However, inhibition of PKCδ did not affect IRF-1 expression or IRF-1 binding to the CIITA promoter. Therefore, we report, for the first time, that PKCδ is an essential signaling molecule to achieve the maximal expression of CIITA in response to IFN-γ in macrophages. In addition, although IRF-1 is a key transcription factor to activate the IFN-γ inducible CIITA promoter, the effect of PKCδ on CIITA expression is mediated primarily by serine phosphorylation of Stat 1. [Copyright &y& Elsevier]