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Background: Feeding on a high-fat diet (HFD) results in obesity and chronic inflammation, which may have long-term effects on neuroinflammation and hippocampal injury. Theabrownin, a biologically active compound derived from the microbial fermentation of Qingzhuan dark tea, exhibits anti-inflammatory properties and lipid-lowering effects. Nevertheless, its potential in neuroprotection has yet to be investigated. Consequently, this study aims to investigate the neuroprotective effects of Theabrownin extracted from Qingzhuan dark tea, as well as its potential therapeutic mechanisms. Methods: Male C57 mice were subjected to an 8-week HFD to induce obesity, followed by oral administration of Theabrownin from Qingzhuan dark tea. Lipid levels were detected by Elisa kit, hippocampal morphological damage was evaluated by HE and Nissl staining, and the expression levels of GFAP, IBA1, NLRP3, MARK4, and BAX in the hippocampus were detected by immunofluorescence (IF), and protein expression levels of NLRP3, MARK4, PSD95, SYN1, SYP, and Bcl-2 were detected by Western Blot (WB). Results: Theabrownin treatment from Qingzhuan dark tea prevents alterations in body weight and lipid levels in HFD-fed mice. Furthermore, Theabrownin decreased hippocampal morphological damage and reduced the activation of astrocytes and microglia in HFD-fed mice. Moreover, Theabrownin decreased the expression of MARK4 and NLRP3 in HFD-fed mice. Besides, Theabrownin elevated the expression of PSD95, SYN1, and SYP in HFD-fed obese mice. Finally, Theabrownin prevented neuronal apoptosis, reduced the expression of BAX, and increased the expression of Bcl-2 in HFD-fed obese mice. Conclusions: In summary, our current study presents the first demonstration of the effective protective effect of Theabrownin from Qingzhuan dark tea against HFD-induced hippocampal damage in obese mice. This protection may result from the regulation of the MARK4/NLRP3 signaling pathway, subsequently inhibiting neuroinflammation, synaptic plasticity, and neuronal apoptosis.

Summary: Microtubule affinity-regulating kinase 4 (MARK4) is a serine/threonine kinase that plays a key role in tau phosphorylation and regulation of the mammalian target of rapamycin (mTOR) pathway. Abnormal tau phosphorylation and dysregulation of the mTOR pathway are implicated in neurodegenerative and neurodevelopmental disorders. Here, we report a gain-of-function variant in MARK4 in two siblings with childhood-onset neurodevelopmental disability and dysmorphic features. The siblings carry a germline heterozygous missense MARK4 variant c.604T>C (p.Phe202Leu), located in the catalytic domain of the kinase, which they inherited from their unaffected, somatic mosaic mother. Functional studies show that this amino acid substitution has no impact on protein expression but instead increases the ability of MARK4 to phosphorylate tau isoforms found in the fetal and adult brain. The MARK4 variant also increases phosphorylation of ribosomal protein S6, indicating upregulation of the mTORC1 pathway. In this study, we link a germline monoallelic MARK4 variant to a childhood-onset neurodevelopmental disorder characterized by global developmental delay, intellectual disability, behavioral abnormalities, and dysmorphic features.

Ischemic injury to white matter tracts is increasingly recognized to play a key role in age-related cognitive decline, vascular dementia, and Alzheimer's disease. Knowledge of the effects of ischemic axonal injury on cortical neurons is limited yet critical to identifying molecular pathways that link neurodegeneration and ischemia. Using a mouse model of subcortical white matter ischemic injury coupled with retrograde neuronal tracing, we employed magnetic affinity cell sorting with fluorescence-activated cell sorting to capture layer-specific cortical neurons and performed RNA-sequencing. With this approach, we identified a role for microtubule reorganization within stroke-injured neurons acting through the regulation of tau. We find that subcortical stroke-injured Layer 5 cortical neurons up-regulate the microtubule affinity-regulating kinase, Mark4, in response to axonal injury. Stroke-induced up-regulation of Mark4 is associated with selective remodeling of the apical dendrite after stroke and the phosphorylation of tau in vivo. In a cell-based tau biosensor assay, Mark4 promotes the aggregation of human tau in vitro. Increased expression of Mark4 after ischemic axonal injury in deep layer cortical neurons provides new evidence for synergism between axonal and neurodegenerative pathologies by priming of tau phosphorylation and aggregation.

Microtubule affinity regulating kinase 4 (MARK4), which is overexpressed in various tumors, is involved in the regulation of cell division, proliferation, migration, and the cell cycle, and has been considered a potential marker for cancer; however, its mechanism of action in gastric cancer (GC) remains unclear. This study aimed to investigate the role of MARK4 in the proliferation, migration, and invasion of GC cell through the MAPK/ERK signaling pathway by targeting MARK4 knockdown. Using The Cancer Genome Atlas data and clinical information, MARK4 expression and its relationship with prognosis were analyzed. Possible pathways involving MARK4 were explored using enrichment analysis. Western blotting and real-time quantitative polymerase chain reaction were used to detect MARK4 expression in GC. After targeted transfection of siRNA, the transfection efficiency of the experimental group was detected in AGS and HGC-27 cells. The effects of knockdown MARK4 on the proliferation, migration, and invasion of GC cells were verified using CCK-8, colony formation, wound healing, and transwell assays. Finally, the relationship between MARK4, the MAPK/ERK pathway, and epithelial-mesenchymal transition in GC was verified by western blotting. MARK4 expression was upregulated in GC and associated with poor prognosis in patients with GC. Enrichment analysis showed that MARK4 was involved in the activation of the MAPK signaling pathway. Western blotting results indicated that MARK4 overexpression promoted the proliferation, migration, and invasion of GC cells through the MAPK/ERK pathway. MARK4 expression was upregulated in GC and promoted the proliferation, migration, and invasion of GC cells through the MAPK/ERK pathway. [ABSTRACT FROM AUTHOR]

Background Microtubule dynamics plays a crucial role in the spatial arrangement of cell organelles and activation of the NLRP3 inflammasome. Purpose This study aimed to explore whether microtubule affinity regulating kinase 4 (MARK4) can be a therapeutic target of periodontitis by affecting microtubule dynamics and NLRP3 inflammasome-mediated pyroptosis in macrophages. Materials and Methods The NLRP3 inflammasome-related genes and MARK4 were measured in the healthy and inflamed human gingival tissues. Bone marrow-derived macrophages (BMDMs) were infected with Porphyromonas gingivalis, while the MARK4 inhibitors (OTSSP167 and Compound 50) and small interference RNA were utilized to restrain MARK4. Apoptosis-associated speck-like protein (ASC) speck was detected by confocal, and levels of interleukin-1β (IL-1β), as well as IL-18, were assessed by ELISA. Results Increased staining and transcription of MARK4, NLRP3, ASC, and Caspase-1 were observed in the inflamed gingiva. P. gingivalis infection promoted MARK4 expression and the NLRP3 inflammasome in BMDMs. Inhibition of MARK4 decreased LDH release, IL-1β and IL-18 production, ASC speck formation, and the pyroptosis-related genes transcription. Furthermore, MARK4 inhibition reduced microtubule polymerization and acetylation in P. gingivalis-infected BMDMs. Conclusions MARK4 promoted NLRP3 inflammasome activation and pyroptosis in P. gingivalis-infected BMDMs by affecting microtubule dynamics. MARK4 inhibition might be a potential target in regulating the NLRP3 inflammasome during periodontitis progress.

In view of the unsatisfactory treatment of cognitive disorders, in particular Alzheimer's disease (AD), the aim of this review was to perform a computer-aided analysis of the state of the art that will help in the search for innovative polypharmacology-based therapeutic approaches to fight against AD. Apart from 20-year unrenewed cholinesterase- or NMDA-based AD therapy, the hope of effectively treating Alzheimer's disease has been placed on serotonin 5-HT6 receptor (5-HT6R), due to its proven, both for agonists and antagonists, beneficial procognitive effects in animal models; however, research into this treatment has so far not been successfully translated to human patients. Recent lines of evidence strongly emphasize the role of kinases, in particular microtubule affinity-regulating kinase 4 (MARK4), Rho-associated coiled-coil-containing protein kinase I/II (ROCKI/II) and cyclin-dependent kinase 5 (CDK5) in the etiology of AD, pointing to the therapeutic potential of their inhibitors not only against the symptoms, but also the causes of this disease. Thus, finding a drug that acts simultaneously on both 5-HT6R and one of those kinases will provide a potential breakthrough in AD treatment. The pharmacophore- and docking-based comprehensive literature analysis performed herein serves to answer the question of whether the design of these kind of dual agents is possible, and the conclusions turned out to be highly promising. [ABSTRACT FROM AUTHOR]

MAP/microtubule affinity-regulating kinase 4 (MARK4) is associated with various biological functions, including neuronal migration, cell polarity, microtubule dynamics, apoptosis, and cell cycle regulation, specifically in the G1/S checkpoint, cell signaling, and differentiation. It plays a critical role in different types of cancers. Hepatocellular carcinoma (HCC) is the one of the most common forms of liver cancer caused due to mutations, epigenetic aberrations, and altered gene expression patterns. Here, we have applied an integrated network biology approach to see the potential links of MARK4 in HCC, and subsequently identified potential herbal drugs. This work focuses on the naturally-derived compounds from medicinal plants and their properties, making them targets for potential anti-hepatocellular treatments. We further analyzed the HCC mutated genes from the TCGA database by using cBioPortal and mapped out the MARK4 targets among the mutated list. MARK4 and Mimosin, Quercetin, and Resveratrol could potentially interact with critical cancer-associated proteins. A set of the hepatocellular carcinoma altered genes is directly the part of infection, inflammation, immune systems, and cancer pathways. Finally, we conclude that among all these drugs, Gingerol and Fisetin appear to be the highly promising drugs against MARK4-based targets, followed by Quercetin, Resveratrol, and Apigenin. [ABSTRACT FROM AUTHOR]

Microtubule affinity regulating kinase 4 (MARK4) regulates the mechanism of microtubules by its ability to phosphorylate the microtubule-associated proteins (MAP's). MARK4 is known for its major role in tau phosphorylation via phosphorylating Ser262 residue in the KXGS motif, which results in the detachment of tau from microtubule. In lieu of this vital role in tau pathology, a hallmark of Alzheimer's disease (AD), MARK4 is a druggable target to treat AD and other neurodegenerative disorders (NDs). There is growing evidence that NDs and diabetes are connected with many pieces of literature demonstrating a high risk of developing AD in diabetic patients. Metformin (Mtf) has been a drug in use against type 2 diabetes mellitus (T2DM) for a long time; however, recent studies have established its therapeutic effect in neurodegenerative diseases (NDs), namely AD, Parkinson's disease (PD) and amnestic mild cognitive impairment. In this study, we have explored the MARK4 inhibitory potential of Mtf, employing in silico and in vitro approaches. Molecular docking demonstrated that Mtf binds to MARK4 with a significant affinity of −6.9 kcal/mol forming interactions with binding pocket's critical residues. Additionally, molecular dynamics (MD) simulation provided an atomistic insight into the binding of Mtf with MARK4. ATPase assay of MARK4 in the presence of Mtf shows that it inhibits MARK4 with an IC50 = 7.05 µM. The results of the fluorescence binding assay demonstrated significant binding of MARK4 with a binding constant of 0.6 × 106 M−1. The present study provides an additional axis towards the utilization of Mtf as MARK4 inhibitor targeting diabetes with NDs. [ABSTRACT FROM AUTHOR]

MAP/microtubule affinity-regulating kinase 4 (MARK4) is associated with various biological functions, including neuronal migration, cell polarity, microtubule dynamics, apoptosis, and cell cycle regulation, specifically in the G1/S checkpoint, cell signaling, and differentiation. It plays a critical role in different types of cancers. Hepatocellular carcinoma (HCC) is the one of the most common forms of liver cancer caused due to mutations, epigenetic aberrations, and altered gene expression patterns. Here, we have applied an integrated network biology approach to see the potential links of MARK4 in HCC, and subsequently identified potential herbal drugs. This work focuses on the naturally-derived compounds from medicinal plants and their properties, making them targets for potential anti-hepatocellular treatments. We further analyzed the HCC mutated genes from the TCGA database by using cBioPortal and mapped out the MARK4 targets among the mutated list. MARK4 and Mimosin, Quercetin, and Resveratrol could potentially interact with critical cancer-associated proteins. A set of the hepatocellular carcinoma altered genes is directly the part of infection, inflammation, immune systems, and cancer pathways. Finally, we conclude that among all these drugs, Gingerol and Fisetin appear to be the highly promising drugs against MARK4-based targets, followed by Quercetin, Resveratrol, and Apigenin.

Microtubule affinity regulating kinase 4 (MARK4), an important member of the serine/threonine kinase family, regulates the phosphorylation of microtubule‐associated proteins and thus modulates microtubule dynamics. In human atherosclerotic lesions, the expression of MARK4 is significantly increased. Recently, accumulating evidence suggests that MARK4 exerts a proatherogenic effect via regulation of lipid metabolism (cholesterol, fatty acid, and triglyceride), inflammation, cell cycle progression and proliferation, insulin signaling, and glucose homeostasis, white adipocyte browning, and oxidative stress. In this review, we summarize the latest findings regarding the role of MARK4 in the pathogenesis of atherosclerosis to provide a rationale for future investigation and therapeutic intervention. [ABSTRACT FROM AUTHOR]

Abstract Background An increasing number of studies have shown that long noncoding RNAs (lncRNAs) play essential roles in tumor initiation and progression. LncRNAs act as tumor promoters or suppressors by targeting specific genes via epigenetic modifications and competing endogenous RNA (ceRNA) mechanisms. In this study, we explored the function and detailed mechanisms of long intergenic nonprotein coding RNA 673 (LINC00673) in breast cancer progression. Methods Quantitative real-time PCR (qRT-PCR) was used to examine the expression of LINC00673 in breast cancer tissues and in adjacent normal tissues. Gain-of-function and loss-of function experiments were conducted to investigate the biological functions of LINC00673 in vitro and in vivo. We also explored the potential role of LINC00673 as a therapeutic target using antisense oligonucleotide (ASO) in vivo. RNA sequencing (RNA-seq), dual-luciferase reporter assays, chromatin immunoprecipitation (ChIP) assay, and rescue experiments were performed to uncover the detailed mechanism of LINC00673 in promoting breast cancer progression. Results In the present study, LINC00673 displayed a trend of remarkably increased expression in breast cancer tissues and was associated with poor prognosis in breast cancer patients. Importantly, LINC00673 depletion inhibited breast cancer cell proliferation by inhibiting the cell cycle and increasing apoptosis. Furthermore, ASO therapy targeting LINC00673 substantially suppressed breast cancer cell proliferation in vivo. Mechanistically, LINC00673 was found to act as a ceRNA by sponging miR-515-5p to regulate MARK4 expression, thus inhibiting the Hippo signaling pathway. Finally, ChIP assay showed that the transcription factor Yin Yang 1 (YY1) could bind to the LINC00673 promoter and increase its transcription in cis. Conclusions YY1-activated LINC00673 may exert an oncogenic function by acting as a sponge for miR-515-5p to upregulate the MARK4 and then inhibit Hippo signaling pathway, and may serve as a potential therapeutic target.

Abstract Ischemic injury to white matter tracts is increasingly recognized to play a key role in age-related cognitive decline, vascular dementia, and Alzheimer’s disease. Knowledge of the effects of ischemic axonal injury on cortical neurons is limited yet critical to identifying molecular pathways that link neurodegeneration and ischemia. Using a mouse model of subcortical white matter ischemic injury coupled with retrograde neuronal tracing, we employed magnetic affinity cell sorting with fluorescence-activated cell sorting to capture layer-specific cortical neurons and performed RNA-sequencing. With this approach, we identified a role for microtubule reorganization within stroke-injured neurons acting through the regulation of tau. We find that subcortical stroke-injured Layer 5 cortical neurons up-regulate the microtubule affinity-regulating kinase, Mark4, in response to axonal injury. Stroke-induced up-regulation of Mark4 is associated with selective remodeling of the apical dendrite after stroke and the phosphorylation of tau in vivo. In a cell-based tau biosensor assay, Mark4 promotes the aggregation of human tau in vitro. Increased expression of Mark4 after ischemic axonal injury in deep layer cortical neurons provides new evidence for synergism between axonal and neurodegenerative pathologies by priming of tau phosphorylation and aggregation.

In view of the unsatisfactory treatment of cognitive disorders, in particular Alzheimer’s disease (AD), the aim of this review was to perform a computer-aided analysis of the state of the art that will help in the search for innovative polypharmacology-based therapeutic approaches to fight against AD. Apart from 20-year unrenewed cholinesterase- or NMDA-based AD therapy, the hope of effectively treating Alzheimer’s disease has been placed on serotonin 5-HT6 receptor (5-HT6R), due to its proven, both for agonists and antagonists, beneficial procognitive effects in animal models; however, research into this treatment has so far not been successfully translated to human patients. Recent lines of evidence strongly emphasize the role of kinases, in particular microtubule affinity-regulating kinase 4 (MARK4), Rho-associated coiled-coil-containing protein kinase I/II (ROCKI/II) and cyclin-dependent kinase 5 (CDK5) in the etiology of AD, pointing to the therapeutic potential of their inhibitors not only against the symptoms, but also the causes of this disease. Thus, finding a drug that acts simultaneously on both 5-HT6R and one of those kinases will provide a potential breakthrough in AD treatment. The pharmacophore- and docking-based comprehensive literature analysis performed herein serves to answer the question of whether the design of these kind of dual agents is possible, and the conclusions turned out to be highly promising.

Microtubule affinity regulating kinase 4 (MARK4) regulates the mechanism of microtubules by its ability to phosphorylate the microtubule-associated proteins (MAP’s). MARK4 is known for its major role in tau phosphorylation via phosphorylating Ser262 residue in the KXGS motif, which results in the detachment of tau from microtubule. In lieu of this vital role in tau pathology, a hallmark of Alzheimer’s disease (AD), MARK4 is a druggable target to treat AD and other neurodegenerative disorders (NDs). There is growing evidence that NDs and diabetes are connected with many pieces of literature demonstrating a high risk of developing AD in diabetic patients. Metformin (Mtf) has been a drug in use against type 2 diabetes mellitus (T2DM) for a long time; however, recent studies have established its therapeutic effect in neurodegenerative diseases (NDs), namely AD, Parkinson’s disease (PD) and amnestic mild cognitive impairment. In this study, we have explored the MARK4 inhibitory potential of Mtf, employing in silico and in vitro approaches. Molecular docking demonstrated that Mtf binds to MARK4 with a significant affinity of −6.9 kcal/mol forming interactions with binding pocket’s critical residues. Additionally, molecular dynamics (MD) simulation provided an atomistic insight into the binding of Mtf with MARK4. ATPase assay of MARK4 in the presence of Mtf shows that it inhibits MARK4 with an IC50 = 7.05 µM. The results of the fluorescence binding assay demonstrated significant binding of MARK4 with a binding constant of 0.6 × 106 M−1. The present study provides an additional axis towards the utilization of Mtf as MARK4 inhibitor targeting diabetes with NDs.

Long non-coding RNA (lncRNA) is an essential regulator of carcinogenesis and cancer progression. In the study, we explored the role of lncRNA DLGAP1-AS1 in gastric cancer (GC). qRT-PCR was carried out to detect DLGAP1-AS1 expression in GC tissues and cell lines. CCK-8 assay, EdU assay, and transwell experiments were employed to detect the malignant biological behaviors of GC cells with DLGAP1-AS1 knockdown or overexpression. Bioinformatics and dual-luciferase report assay were used to confirm the binding relationship between DLGAP1-AS1 and miR-515-5p. MARK4 expression was detected by western blot after DLGAP1-AS1/miR-515-5p was selectively regulated. DLGAP1-AS1 was up-regulated in GC tissues and cell lines, and its high expression was closely associated with larger tumor size, higher TNM stage, and lymph node metastasis. Furthermore, DLGAP1-AS1 overexpression enhanced cell proliferation, migration, and invasion, and miR-515-5p could reverse these effects. DLGAP1-AS1 participated in the regulation of the MARK4 signaling pathway by targeting miR-515-5p. DLGAP1-AS1 promoted GC progression through miR-515-5p/MARK4 signaling pathway.

Accumulation of abnormally phosphorylated tau proteins is linked to various neurodegenerative diseases, including Alzheimer's disease and frontotemporal dementia. Microtubule affinity-regulating kinase 4 (MARK4) has been genetically and pathologically associated with Alzheimer's disease and reported to enhance tau phosphorylation and toxicity in Drosophila and mouse traumatic brain-injury models but not in mammalian tauopathy models. To investigate the role of MARK4 in tau-mediated neuropathology, we crossed P301S tauopathy model (PS19) and Mark4 knockout mice. We performed behaviour, biochemical and histology analyses to evaluate changes in PS19 pathological phenotype with and without Mark4. Here, we demonstrated that Mark4 deletion ameliorated the tau pathology in a mouse model of tauopathy. In particular, we found that PS19 with Mark4 knockout showed improved mortality and memory compared with those bearing an intact Mark4 gene. These phenotypes were accompanied by reduced neurodegeneration and astrogliosis in response to the reduction of pathological forms of tau, such as those phosphorylated at Ser356, AT8-positive tau and thioflavin S-positive tau. Our data indicate that MARK4 critically contributes to tau-mediated neuropathology, suggesting that MARK4 inhibition may serve as a therapeutic avenue for tauopathies., Competing Interests: The authors report no competing interests., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Guarantors of Brain.)

The aim of this investigation was to evaluate the role of MARK4 in the regulation of oxidative stress and mitochondrial dysfunction in pig placental trophoblasts and analyze the signaling pathways involved. In this study, we found that enhanced MARK4 contributed to augmented oxidative stress in pig trophoblasts, as evidenced by decreased total antioxidant capacity (TAC); higher production of reactive oxygen species (ROS); elevated protein carbonylation; and reduced SOD, CAT, and GSH-PX activities. Further analyses revealed MARK4 impaired mitochondrial oxidative respiration in cultured trophoblasts, which was associated with reduced ATP content, decreased mitochondrial membrane potential, lower mitochondrial Complexes I and III activities, and down-regulated protein contents of subunits of complexes I, II, and V. At same time, mitochondrial biogenesis and structure were negatively altered by elevated MARK4. By antioxidant treatment with vitamin E (VE), oxidative stress along with impaired mitochondrial function induced by enhanced MARK4 were blocked. Furthermore, we found activation of AMPK signaling prevented MARK4 from blocking mitochondrial biogenesis and function in pig trophoblast cells. Finally, we demonstrated that the IKKα/NF-κB signal pathway was involved in MARK4 activated oxidative stress and mitochondrial dysfunction. Thus, these data suggest that MARK4 promotes oxidative stress and mitochondrial injury in porcine placental trophoblasts and can contribute to the developing of knowledge of pathological processes leading to mitochondrial dysfunction associated with excessive back-fat in the pig placenta and to the obesity-associated pregnant syndrome.

Gliomas are the most common primary intracranial neoplasms among all brain malignancies, and the microtubule affinity regulating kinases (MARKs) have become potential drug targets for glioma. Here, we report a novel dual small-molecule inhibitor of MARK3 and MARK4, designated as PCC0208017. In vitro, PCC0208017 strongly inhibited kinase activity against MARK3 and MARK4, and strongly reduced proliferation in three glioma cell lines. This compound attenuated glioma cell migration, glioma cell invasion, and angiogenesis. Molecular mechanism studies revealed that PCC0208017 decreased the phosphorylation of Tau, disrupted microtubule dynamics, and induced a G2/M phase cell cycle arrest. In an in vivo glioma model, PCC0208017 showed robust anti-tumor activity, blood–brain barrier permeability, and a good oral pharmacokinetic profile. Molecular docking studies showed that PCC0208017 exhibited high binding affinity to MARK3 and MARK4. Taken together, our study describes for the first time that PCC0208017, a novel MARK3/MARK4 inhibitor, might be a promising lead compound for treatment of glioma. PCC0208017 inhibits the activity of MARK3 and MARK4 and suppresses the growth, migration and invasion of glioma cells, as well as inhibit the angiogenesis. Importantly, PCC0208017 shows robust in vivo anti-tumor activity and demonstrates well pharmacokinetic profile and blood–brain barrier permeability. Image 1 [ABSTRACT FROM AUTHOR]

Introduction: We compared genetic variants between Alzheimer's disease (AD) and two age‐related cancers—breast and prostate —to identify single‐nucleotide polymorphisms (SNPs) that are associated with inverse comorbidity of AD and cancer. Methods: Bayesian multinomial regression was used to compare sex‐stratified cases (AD and cancer) against controls in a two‐stage study. A ±500 KB region around each replicated hit was imputed and analyzed after merging individuals from the two stages. The microRNAs (miRNAs) that target the genes involving these SNPs were analyzed for miRNA family enrichment. Results: We identified 137 variants with inverse odds ratios for AD and cancer located on chromosomes 19, 4, and 5. The mapped miRNAs within the network were enriched for miR‐17 and miR‐515 families. Discussion: The identified SNPs were rs4298154 (intergenic), within TOMM40/APOE/APOC1, MARK4, CLPTM1, and near the VDAC1/FSTL4 locus. The miRNAs identified in our network have been previously reported to have inverse expression in AD and cancer. [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) is one of the most prevalent cancers worldwide. Nowadays, pharmacological therapy for HCC is in urgent needs. Paclitaxel is an effective drug against diverse solid tumors, but commonly resisted in HCC patients. We recently have disclosed that microtubule affinity-regulating kinase 4 (MARK4) increases the microtubule dynamics and confers paclitaxel resistance in HCC, suggesting MARK4 as an attractive target to overcome paclitaxel resistance. Herein, we synthesized and identified coumarin derivatives 50 as a novel MARK4 inhibitor. Biological evaluation indicated compound 50 directly interacted with MARK4 and inhibited its activity in vitro, suppressed cell viability and induced apoptosis of HCC cells in a MARK4-dependent manner. Importantly, compound 50 significantly increased the drug response of paclitaxel treatment to HCC cells, providing a promise strategy to HCC treatment and broadening the application of paclitaxel in cancer therapy.

Background: Feeding on a high-fat diet (HFD) results in obesity and chronic inflammation, which may have long-term effects on neuroinflammation and hippocampal injury. Theabrownin, a biologically active compound derived from the microbial fermentation of Qingzhuan dark tea, exhibits anti-inflammatory properties and lipid-lowering effects. Nevertheless, its potential in neuroprotection has yet to be investigated. Consequently, this study aims to investigate the neuroprotective effects of Theabrownin extracted from Qingzhuan dark tea, as well as its potential therapeutic mechanisms., Methods: Male C57 mice were subjected to an 8-week HFD to induce obesity, followed by oral administration of Theabrownin from Qingzhuan dark tea. Lipid levels were detected by Elisa kit, hippocampal morphological damage was evaluated by HE and Nissl staining, and the expression levels of GFAP, IBA1, NLRP3, MARK4, and BAX in the hippocampus were detected by immunofluorescence (IF), and protein expression levels of NLRP3, MARK4, PSD95, SYN1, SYP, and Bcl-2 were detected by Western Blot (WB)., Results: Theabrownin treatment from Qingzhuan dark tea prevents alterations in body weight and lipid levels in HFD-fed mice. Furthermore, Theabrownin decreased hippocampal morphological damage and reduced the activation of astrocytes and microglia in HFD-fed mice. Moreover, Theabrownin decreased the expression of MARK4 and NLRP3 in HFD-fed mice. Besides, Theabrownin elevated the expression of PSD95, SYN1, and SYP in HFD-fed obese mice. Finally, Theabrownin prevented neuronal apoptosis, reduced the expression of BAX, and increased the expression of Bcl-2 in HFD-fed obese mice., Conclusions: In summary, our current study presents the first demonstration of the effective protective effect of Theabrownin from Qingzhuan dark tea against HFD-induced hippocampal damage in obese mice. This protection may result from the regulation of the MARK4/NLRP3 signaling pathway, subsequently inhibiting neuroinflammation, synaptic plasticity, and neuronal apoptosis., Competing Interests: 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., (© 2024 Published by Elsevier Ltd.)

Vascular calcification (VC) is directly related to high mortality in chronic kidney disease (CKD), and cellular apoptosis of vascular smooth muscle cells (VSMCs) is a crucial process in the initiation of VC. Microtubule affinity-regulating kinase 4 (Mark4), known as a serine/threonine protein kinase, can induce cell apoptosis and autophagy by modulating Akt phosphorylation. However, the potential functions and molecular mechanisms of Mark4 in VSMCs apoptosis and calcification need to be further explored. Initially, our data indicated that the mRNA expression of Mark4 was prominently elevated in high phosphorus-stimulated human VSMCs compared with the other members in Marks. Consistently, Mark4 expression was found to be significantly increased in the calcified arteries of both CKD patients and rats. In vitro , silencing Mark4 suppressed apoptosis-specific marker expression by promoting Akt phosphorylation, finally attenuating VSMCs calcification induced by high phosphate. Mechanically, the transcription factor Sp1 was enriched in the Mark4 promoter region and modulated Mark4 transcription. Moreover, SET domain-containing protein 8 (Setd8) was proved to interact with Sp1 and jointly participated in the transcriptional regulation of Mark4. Finally, rescue experiments revealed that Setd8 contributed to VSMCs apoptosis and calcification by modulating Mark4 expression. In conclusion, these findings reveal that Mark4 is transcriptionally activated by Sp1, which is interacted with Setd8, to promote VSMCs calcification through Akt-mediated antiapoptotic effects, suggesting that Mark4 represents a potent and promising therapeutic target for VC in CKD.

Microtubule affinity-regulating kinase 4 (MARK4) is a serine/threonine kinase that plays a key role in tau phosphorylation and regulation of the mammalian target of rapamycin (mTOR) pathway. Abnormal tau phosphorylation and dysregulation of the mTOR pathway are implicated in neurodegenerative and neurodevelopmental disorders. Here, we report a gain-of-function variant in MARK4 in two siblings with childhood-onset neurodevelopmental disability and dysmorphic features. The siblings carry a germline heterozygous missense MARK4 variant c.604T>C (p.Phe202Leu), located in the catalytic domain of the kinase, which they inherited from their unaffected, somatic mosaic mother. Functional studies show that this amino acid substitution has no impact on protein expression but instead increases the ability of MARK4 to phosphorylate tau isoforms found in the fetal and adult brain. The MARK4 variant also increases phosphorylation of ribosomal protein S6, indicating upregulation of the mTORC1 pathway. In this study, we link a germline monoallelic MARK4 variant to a childhood-onset neurodevelopmental disorder characterized by global developmental delay, intellectual disability, behavioral abnormalities, and dysmorphic features., Competing Interests: The authors declare no competing interests., (© 2023 The Authors.)

Highlights • Excessive back-fat of sows at mating leads to increased oxidative stress and mitochondrial injury in the full-term placenta. • Augmented apoptosis in pig term placenta is associated with excessive back-fat. • Activation of mitochondrial apoptotic pathway contributes to apoptosis in term placenta of sows with excessive back-fat. Abstract The objective of this investigation was to evaluate the influence of back-fat thickness (BF), at mating of sows, on the placental oxidative stress, mitochondrial injury and apoptosis. For that purpose, we performed iTRAQ labeling based proteomic analysis on term placentas obtained by vaginal delivery from BFI (15–20 mm) and BFII (21–27 mm) sows formed according to BF at mating. Proteomic analysis revealed 413 proteins to be significantly different in placenta from BFII sows by ≥1.2-fold. Gene ontology (GO) analysis identified proteins related to oxidative stress response and apoptotic process to be altered in placenta from BFII sows. Indicative of increased oxidative stress and impaired mitochondrial function, higher placental MDA, H 2 O 2 and O2− levels and reduced CAT and SOD activities were linked to decreased mitochondrial membrane potential and reduced mitochondrial DNA copy number and increased MPTP opening activity in placenta from BFII group (P < 0.05). Furthermore, a TUNEL apoptosis assay showed that increased back-fat triggered a 33% increase of apoptotic cells in placental villi; and apoptosis was confirmed by the decreased protein contents of Bcl-2, as well as the increased expression of Bax, cytochrome c , Apaf-1, caspase 9 and cleaved caspase 3 in placenta from BFII sows that was associated with higher caspase 3 activity (P < 0.05), suggesting the activation of mitochondrial apoptotic pathway. Excessive back-fat was also associated with increased activation of Mark4 and JNK1 and reduced activation of p38 MAPK in pig term placenta, suggesting the potential mechanisms underlying increased oxidative stress and apoptosis in placenta from BFII sows. Together, these findings indicate that excessive back-fat of sows at mating leads to increased oxidative stress that is associated with mitochondrial dysfunction and augmented apoptosis in the full-term placenta. [ABSTRACT FROM AUTHOR]

Autophagy can remove excess or dysfunctional proteins and organelles to maintain cellular homeostasis. Browning of white adipose tissue increases the energy expenditure. Microtubules affinity regulated kinase 4 (Mark4) can regulate a variety of physiological processes. According to previous studies, we speculated that Mark4-autophagy-browning of white adipose tissue had certain linkages. Here, we established two autophagy models through serum starvation and rapamycin treatment and detected that the overexpression of Mark4 increased the expression of autophagy-related factors Beclin1, ATG7, and significantly decreased the autophagy substrate P62. Further tests showed that the overexpression of Mark4 promoted the conversion of autophagy marker protein LC3A to LC3B-II by activating the AMP-activated protein kinase (AMPK) pathway and inhibition of the AKT/mTOR signaling. Moreover, Mark4 decreased the expression of thermogenesis genes via promoting autophagy. These results indicated that Mark4 inhibited the browning of white adipose tissue via promoting autophagy.

This study aimed to characterize the full-length cDNA of MARK4 in Sus scrofa, and evaluated its potential role in the regulation of lipid accumulation in pig placental trophoblasts and analyzed signaling pathways involved, thereby providing insights into mechanisms for placental lipotoxicity induced by excessive back-fat during pregnancy of sows. The cDNA obtained with 5′ and 3′ RACE amplification covered 3216 bp with an open reading frame of 2259 bp encoding 752 amino acids. Multiple alignments and phylogenetic analysis revealed MARK4 protein of Sus scrofa had a high homology (95%–99%) to that of other higher vertebrates. After transfection, enhanced MARK4 significantly promoted lipogenesis in pig trophoblasts, as evidenced by accelerated lipid accumulation and consistently increased mRNA expressions of lipogenic genes DGAT1, LPIN1, LPIN3, LPL, PPARδ and SREBP-1c. Meanwhile, PPARγ remarkably inhibited the stimulating effect of MARK4 on non-receptor-mediated lipid accumulation in trophoblasts. Further analyses revealed WNT signaling enhanced lipid accumulation and activation of MARK4 in pig trophoblast cells. Finally, we demonstrated that WNT/β-catenin signal pathway is involved in MARK4 activated lipogenesis. These results suggest that MARK4 promotes lipid accumulation in porcine placental trophoblasts and can be considered as a potential regulator of lipotoxicity associated with maternal obesity in the pig placenta.

Individuals with Down syndrome (DS) overexpress many genes on chromosome 21 due to trisomy and have high risk of dementia due to the Alzheimer's disease (AD) neuropathology. However, there is a wide range of phenotypic differences (e.g., age at onset of AD, amyloid β levels) among adults with DS, suggesting the importance of factors that modify risk within this particularly vulnerable population, including genotypic variability. Previous genetic studies in the general population have identified multiple genes that are associated with AD. This study examined the contribution of polymorphisms in these genes to the risk of AD in adults with DS ranging from 30 to 78 years of age at study entry (N = 320). We used multiple logistic regressions to estimate the likelihood of AD using single-nucleotide polymorphisms (SNPs) in candidate genes, adjusting for age, sex, race/ethnicity, level of intellectual disability and APOE genotype. This study identified multiple SNPs in APP and CST3 that were associated with AD at a gene-wise level empirical p -value of 0.05, with odds ratios in the range of 1.5–2. SNPs in MARK4 were marginally associated with AD. CST3 and MARK4 may contribute to our understanding of potential mechanisms where CST3 may contribute to the amyloid pathway by inhibiting plaque formation, and MARK4 may contribute to the regulation of the transition between stable and dynamic microtubules. [ABSTRACT FROM AUTHOR]

The Hippo pathway is a critical regulator of tissue size, and aberrations in pathway regulation lead to cancer. MST1/2 and LATS1/2 kinases comprise the core of the pathway that, in association with adaptor proteins SAV and MOB, functions in a sequential manner to phosphorylate and inhibit the transcription factors YAP and TAZ. Here we identify mammalian MARK family members as activators of YAP/TAZ. We show that depletion of MARK4 in MDA-MB-231 breast cancer cells results in the loss of nuclear YAP/TAZ and decreases the expression of YAP/TAZ targets. We demonstrate that MARK4 can bind to MST and SAV, leading to their phosphorylation, and that MARK4 expression attenuates the formation of a complex between MST/SAV and LATS, which depends on the kinase activity of MARK4. Abrogation of MARK4 expression using siRNAs and CRISPR/Cas9 gene editing attenuates the proliferation and migration of MDA-MB-231 cells. Our results show that MARK4 acts as a negative regulator of the Hippo kinase cassette to promote YAP/TAZ activity and that loss of MARK4 restrains the tumorigenic properties of breast cancer cells. [ABSTRACT FROM AUTHOR]

Microtubule-associated protein/microtubule affinity-regulating kinase 4 (MARK4) is a serine/threonine kinase involved in the phosphorylation of MAP proteins that regulate microtubule dynamics. Abnormal activity of MARK4 has been proposed to contribute to neurofibrillary tangle formation in Alzheimer's disease. The crystal structure of the catalytic and ubiquitin-associated domains of MARK4 with a potent pyrazolopyrimidine inhibitor has been determined to 2.8 Å resolution with an Rwork of 22.8%. The overall structure of MARK4 is similar to those of the other known MARK isoforms. The inhibitor is located in the ATP-binding site, with the pyrazolopyrimidine group interacting with the inter-lobe hinge region while the aminocyclohexane moiety interacts with the catalytic loop and the DFG motif, forcing the activation loop out of the ATP-binding pocket. [ABSTRACT FROM AUTHOR]

Microtubule affinity regulating kinase (MARK4) has been proposed as a potential therapeutic target for diabetes, cancer, and neurological diseases. We used a variety of computational studies techniques to examine the binding affinity and MARK4 inhibitory potential of several isoquinoline alkaloids. MARK4 has been associated with tau protein phosphorylation and, consequently, Alzheimer's disease. The three molecules with the highest binding affinities inside the 5ES1 receptor, according to molecular docking experiments, are isoliensinine, liensinine, and methylcorypalline. Isoliensinine had the highest drug score and drug likeness, coming in at 1.17, while Liensinine and Methylcorypalline came in at 1.15 and 1.07, respectively. The thesis claims that three compounds have a better chance than the others of being identified as therapeutic leads. The bulk of the compounds under investigation didn't break any of Lipinski's five rules, especially methylcorypalline, which did and is probably orally active. The majority of the compounds under investigation, particularly Isoliensinine, Liensinine, and Methylcorypalline, show the potential to exhibit drug-like behaviour, which is strongly confirmed by ADMET characteristics estimates. The chemicals Isoliensinine, Liensinine, and Methylcorypalline, especially Methylcorypalline, form the most stable combination with the 5ES1, according to a 100 ns molecular dynamics simulation of these compounds docked inside 5ES1 complexes. Methylcorypalline has a higher binding affinity inside 5ES1, according to additional MM/GBSA experiments using MD trajectories. Overall, research supports the use of the drug development tool methylcolipalin for its ability to inhibit MARK4, which may have implications for the treatment of neurodegenerative diseases.Communicated by Ramaswamy H. Sarma.

MAP/microtubule affinity-regulating kinase 4 (MARK4) is a serine–threonine kinase that phosphorylates microtubule-associated proteins taking part in the regulation of microtubule dynamics. MARK4 is expressed in two spliced isoforms characterized by inclusion (MARK4S) or exclusion (MARK4L) of exon 16. The distinct expression profiles in the central nervous system and their imbalance in gliomas point to roles of MARK4L and MARK4S in cell proliferation and cell differentiation, respectively. Having ruled out mutations and transcription defects, we hypothesized that alterations in the expression of splicing factors may underlie deregulated MARK4 expression in gliomas. Bioinformatic analysis revealed four putative polypyrimidine-tract binding (PTB) protein binding sites in MARK4 introns 15 and 16. Glioma tissues and glioblastoma-derived cancer stem cells showed, compared with normal brain, significant overexpression of PTB, correlated with high MARK4L mRNA expression. Splicing minigene assays revealed a functional intronic splicing silencer in MARK4 intron 15, but mutagenesis of the PTB binding site in this region did not affect minigene splicing, suggesting that PTB may bind to a splicing silencer other than the predicted one and synergistically acting with the other predicted PTB sites. Electrophoretic mobility shift assays coupled with mass spectrometry confirmed binding of PTB to the polypyrimidine tract of intron 15, and thus its involvement in MARK4 alternative splicing. This finding, along with evidence of PTB overexpression in gliomas and glioblastoma-derived cancer stem cells and differentiated progeny, merged in pointing out the involvement of PTB in the switch to MARK4L, consistent with its established role in driving oncogenic splicing in brain tumors. [ABSTRACT FROM AUTHOR]

MARKs kinase belongs to an AMPK-related family kinase plays a critical role in tumor progression, but its exact role and contribution of four different isoforms remain largely ambiguous. In this study, we used a clinical dataset compiled by The Cancer Genome Atlas (TCGA) and GEO revealed that MARK2 and MARK4 expressions were significantly upregulated in non-small cell lung cancer (NSCLC) compared with normal tissues. Furthermore, expressions of MARK2/4 were highly appeared in advanced stages and associated with the low survival rate of NSCLC patients. Functional assays demonstrated that MARK2/4 deletion or MARKs inhibition significantly suppressed aerobic glycolysis and cell growth in NSCLC cells. Mechanistically, MARK2/4 stimulates the mTOR/HIF-1α pathway and subsequently alleviates AMPK activity via physically associate with Raptor and AMPKα1, thereby facilitating aerobic glycolysis and cell growth in NSCLC cells. However, these effects were markedly reversed by MARKs inhibitor 39621, or MARK2/4 deletion, mTOR inhibitor rapamycin, or AMPK activator AICAR. Together, the data demonstrated that MARK2/4 exerts its oncogenic effects by facilitating metabolic reprogramming in NSCLC cells. Therefore, MARK2/4 might be a potential therapeutic target for lung cancer. • High expressions of MARK2/4 facilitate aerobic glycolysis and NSCLC cell growth by suppressing cell death process. • MARK2/4 promotes mTOR/HIF-1α-mediated aerobic glycolysis and cell growth through alleviates AMPKα1 represses HIF-1α activity in NSCLC cells. • MARK2/4 attenuates AMPKα1/p53-mediated cell cycle arrest and cell death, which leads to the progression of NSCLC tumorigenesis. [ABSTRACT FROM AUTHOR]

Background Information Microtubule affinity-regulating kinase 4 (MARK4) deficiency has been reported to negatively regulate diet-induced obesity and to mitigate insulin resistance in knockout mice, and thus may play a role in metabolic syndrome. However, the details of the molecular mechanism have yet to be revealed and the impacts of MARK4 on apoptosis remain unexplored. This study investigated the role of Mark4 in the regulation of lipid accumulation and apoptosis in adipocytes and analysed signalling pathways involved. Results We found that Mark4 significantly up-regulated the expression of gene sterol regulatory element binding protein-1c (SREBP-1c), fatty acid synthase (FAS), acetyl-CoA carboxylase-α (ACCα) and peroxisome proliferator activated receptor-γ (PPARγ); and reduced the protein contents of adipose triglyceride lipase (ATGL), as evidenced by the dramatic increasing lipid droplet accumulation in 3T3-L1 cells. Furthermore, a terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) apoptosis assay showed that Mark4 triggered apoptosis of adipocytes; and apoptosis was confirmed by the decreased protein contents of B-cell lymphoma-2 (Bcl-2), full-length caspase-3 and full-length caspase-9, as well as the increased expression of Bax, cleaved caspase-3 and cleaved caspase-9. Analysis of special inhibitors allowed us to offer the following explanation for these impacts of Mark4: activation of Jun N-terminal kinase1 (JNK1) promoted both apoptosis and adipogenesis, whereas inhibition of the p38 mitogen-activated protein kinase (p38MAPK) pathway contributed to lipid accumulation alone. Conclusions Mark4 promotes adipogenesis in 3T3-L1 adipocytes by activating the JNK1 and inhibiting the p38MAPK pathway, and triggers apoptosis by activating the JNK1 pathway. We conclude that anti- Mark4 therapy targetted to inhibit lipid accumulation and apoptosis of adipocytes shows potential as a novel therapeutic strategy for treatment of obesity-associated metabolic complications. [ABSTRACT FROM AUTHOR]

MARK4 is a serine-threonine kinase that phosphorylates MAP proteins, increasing microtubule dynamics. MARK4 differs from the other members of the MARK family for encoding two isoforms (MARK4L and MARK4S), differentially expressed in the nervous system, and for the peculiar localisation at the centrosome and the midbody. By cytofluorimetric analysis we showed that MARK4 is expressed throughout the cell cycle and preferentially activated during mitosis. Depletion of MARK4S affected the morphology and proliferation of fibroblasts and glioma cells, as the percentages of cells in S and G2/M phases were reduced and the percentage of cells in G1 was increased. In MARK4S silenced cells, centrosomes were duplicated and positioned apically to the nucleus, indicating that the centrosome cycle was altered and the cells arrested in G1 phase. Overexpression of MARK4L or MARK4S reduced the density of the microtubule network, confirming microtubules as the main target of MARK4, and revealed a novel co-localisation of MARK4 and vimentin. Taken together, our data confirm that MARK4 is a key component in the regulation of microtubule dynamics and highlight its major role in cell cycle progression, particularly at the G1/S transition. The co-localisation of vimentin and MARK4L suggests that MARK4 has a wide-ranging influence on cytoskeleton. [ABSTRACT FROM AUTHOR]

During the seminiferous epithelial cycle of spermatogenesis, the ectoplasmic specialization (ES, a testis-specific adherens junction, AJ, type) maintains the polarity of elongating/elongated spermatids and confers adhesion to Sertoli cells in the seminiferous epithelium, and known as the apical ES. On the other hand, the ES is also found at the Sertoli-Sertoli cell interface at the blood-testis barrier (BTB) known as basal ES, which together with the tight junction (TJ), maintains Sertoli cell polarity and adhesion, creating a functional barrier that limits paracellular transport of substances across the BTB. However, the apical and basal ES are segregated and restricted to the adluminal compartment and the BTB, respectively. During the transit of preleptotene spermatocytes across the BTB and the release of sperm at spermiation at stage VIII of the seminiferous epithelial cycle, both the apical and basal ES undergo extensive restructuring to facilitate cell movement at these sites. The regulation of these events, in particular their coordination, remains unclear. Studies in other epithelia have shown that the tubulin cytoskeleton is intimately related to cell movement, and MArK [microtubule-associated protein (MAp)/microtubule affinity-regulating kinase] family kinases are crucial regulators of tubulin cytoskeleton stability. Herein MArK4, the predominant member of the MARK protein family in the testis, was shown to be expressed by both Sertoli and germ cells. MARK4 was also detected at the apical and basal ES, displaying highly restrictive spatiotemporal expression at these sites, as well as co-localizing with markers of the apical and basal ES. the expression of MARK4 was found to be stage-specific during the epithelial cycle, structurally associating with α-tubulin and the desmosomal adaptor plakophilin-2, but not with actin-based BTB proteins occludin, β-catenin and Eps8 (epidermal growth factor receptor pathway substrate 8, an actin bundling and barbed end capping protein). More importantly, it was shown that the expression of MARK4 tightly associated with the integrity of the apical ES because a diminished expression of MARK4 associated with apical ES disruption that led to the detachment of elongating/elongated spermatids from the epithelium. these findings thus illustrate that the integrity of apical ES, an actin-based and testis-specific AJ, is dependent not only on the actin filament network, but also on the tubulin-based cytoskeleton. [ABSTRACT FROM AUTHOR]

In the mammary gland, Wnt signals are strongly implicated in initial development of the mammary rudiments and in the ductal branching and alveolar morphogenesis that occurs during pregnancy. Previously, we identified two Wnt signaling pathway-implicated genes, PPP3CA and MARK4, as having a role in more aggressive and potentially metastatic breast tumors. In this study, we examined two SNPs within PPP3CA and MARK4 in an Australian case-control study population for a potential role in human breast cancers. 182 cases and 180 controls were successfully genotyped for the PPP3CA SNP (rs2850328) and 182 cases and 177 controls were successfully genotyped for the MARK4 SNP (rs2395) using High Resolution Melt (HRM) analysis. Genotypes of randomly selected samples for both SNPs were validated by dye terminator sequencing. Chi-square tests were performed to determine any significant differences in the genotype and allele frequencies between the cases and controls. Chi-square analysis showed no statistically significant difference (ρ > .05) for genotype frequencies between cases and controls for rs2850328 (χ2 = 1.2, p = .5476) or rs2395 (χ2 = .3, p = .8608). Similarly, no statistical difference was observed for allele frequencies for rs2850328 (χ2 = .68, p = .4108) or rs2395 (χ2 = .02, p = .893). Even though an association of the polymorphisms rs2850328 and rs2395 and breast cancer was not detected in our case-control study population, other variants within the PPP3CA and MARK4 genes may still be associated with breast cancer, as both genes are implicated with processes involved in the disease as well as their mutual partaking in the Wnt signaling pathway. [ABSTRACT FROM PUBLISHER]

The aim of this investigation was to evaluate the role of MARK4 in the regulation of oxidative stress and mitochondrial dysfunction in pig placental trophoblasts and analyze the signaling pathways involved. In this study, we found that enhanced MARK4 contributed to augmented oxidative stress in pig trophoblasts, as evidenced by decreased total antioxidant capacity (TAC); higher production of reactive oxygen species (ROS); elevated protein carbonylation; and reduced SOD, CAT, and GSH-PX activities. Further analyses revealed MARK4 impaired mitochondrial oxidative respiration in cultured trophoblasts, which was associated with reduced ATP content, decreased mitochondrial membrane potential, lower mitochondrial Complexes I and III activities, and down-regulated protein contents of subunits of complexes I, II, and V. At same time, mitochondrial biogenesis and structure were negatively altered by elevated MARK4. By antioxidant treatment with vitamin E (VE), oxidative stress along with impaired mitochondrial function induced by enhanced MARK4 were blocked. Furthermore, we found activation of AMPK signaling prevented MARK4 from blocking mitochondrial biogenesis and function in pig trophoblast cells. Finally, we demonstrated that the IKKα/NF-κB signal pathway was involved in MARK4 activated oxidative stress and mitochondrial dysfunction. Thus, these data suggest that MARK4 promotes oxidative stress and mitochondrial injury in porcine placental trophoblasts and can contribute to the developing of knowledge of pathological processes leading to mitochondrial dysfunction associated with excessive back-fat in the pig placenta and to the obesity-associated pregnant syndrome. [ABSTRACT FROM AUTHOR]

Background: Microtubule dynamics plays a crucial role in the spatial arrangement of cell organelles and activation of the NLRP3 inflammasome., Purpose: This study aimed to explore whether microtubule affinity regulating kinase 4 (MARK4) can be a therapeutic target of periodontitis by affecting microtubule dynamics and NLRP3 inflammasome-mediated pyroptosis in macrophages., Materials and Methods: The NLRP3 inflammasome-related genes and MARK4 were measured in the healthy and inflamed human gingival tissues. Bone marrow-derived macrophages (BMDMs) were infected with Porphyromonas gingivalis, while the MARK4 inhibitors (OTSSP167 and Compound 50) and small interference RNA were utilized to restrain MARK4. Apoptosis-associated speck-like protein (ASC) speck was detected by confocal, and levels of interleukin-1β (IL-1β), as well as IL-18, were assessed by ELISA., Results: Increased staining and transcription of MARK4, NLRP3, ASC, and Caspase-1 were observed in the inflamed gingiva. P. gingivalis infection promoted MARK4 expression and the NLRP3 inflammasome in BMDMs. Inhibition of MARK4 decreased LDH release, IL-1β and IL-18 production, ASC speck formation, and the pyroptosis-related genes transcription. Furthermore, MARK4 inhibition reduced microtubule polymerization and acetylation in P. gingivalis- infected BMDMs., Conclusions: MARK4 promoted NLRP3 inflammasome activation and pyroptosis in P. gingivalis- infected BMDMs by affecting microtubule dynamics. MARK4 inhibition might be a potential target in regulating the NLRP3 inflammasome during periodontitis progress., Competing Interests: No potential conflict of interest was reported by the author(s)., (© 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.)