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Background: Porcine skeletal muscle development is pivotal for improving meat production. TP63, a transcription factor, regulates vital cellular processes, yet its role in skeletal muscle proliferation is unclear. Methods: The effects of TP63 on skeletal muscle cell viability and proliferation were investigated using both mouse and porcine skeletal muscle myoblasts. Selective sweep analysis in Western pigs identified TP63 as a potential candidate gene for skeletal muscle development. The correlation between TP63 overexpression and cell proliferation was assessed using quantitative real-time PCR (RT-qPCR) and 5-ethynyl-2’-deoxyuridine (EDU). Results: The study revealed a positive correlation between TP63 overexpression and skeletal muscle cell proliferation. Bioinformatics analysis predicted an interaction between MEF2A, another transcription factor, and the mutation site of TP63. Experimental validation through dual-luciferase assays confirmed that a candidate enhancer SNP could influence MEF2A binding, subsequently regulating TP63 expression and promoting skeletal muscle cell proliferation. Conclusion: These findings offer experimental evidence for further exploration of skeletal muscle development mechanisms and the advancement of genetic breeding strategies aimed at improving meat production traits. [ABSTRACT FROM AUTHOR]

RNA binding proteins have been shown to regulate heart development and cardiac diseases. However, the detailed molecular mechanisms is not known. In this study, we identified Wilms' tumor 1-associating protein (WTAP, a key regulatory protein of the m6A RNA methyltransferase complex) as a key regulator of heart function and cardiac diseases. WTAP is associated with heart development, and its expression is downregulated in both human and mice with heart failure. Cardiomyocyte-specific knockout of Wtap (Wtap -CKO) induces dilated cardiomyopathy, heart failure and neonatal death. Although WTAP deficiency in the heart decreases METTL3 (methyltransferase-like 3) protein levels, cardiomyocyte-specific overexpression of Mettl3 in Wtap -CKO mice does not rescue the phenotypes of Wtap -CKO mice. Instead, WTAP deficiency in the heart decreases chromatin accessibility in the promoter regions of Mef2a (myocyte enhancer factor-2α) and Mef2c , leading to reduced mRNA and protein levels of these genes and lower expression of their target genes. Conversely, WTAP directly binds to the promoter of the Mef2c gene and increases its promoter luciferase activity and expression. These data demonstrate that WTAP plays a key role in heart development and cardiac function by maintaining the chromatin accessibility of cardiomyocyte specific genes. [Display omitted] • WTAP is downregulated during heart development and pathogenesis of heart failure. • Wtap deletion in heart induces dilated cardiomyopathy and neonatal death. • WTAP regulates heart function independent of METTL3. • WTAP deficiency in heart decreases chromatin accessibility of Mef2a and Mef2c. • WTAP promotes Mef2c expression by binding to its promoter. [ABSTRACT FROM AUTHOR]

Abstract Background This study aimed to investigate the role of histone deacetylase 5 (HDAC5) in ventricular remodeling and explore the therapeutic potential of the HDAC5 inhibitor LMK235. Methods A transverse aortic constriction (TAC) mouse model and angiotensin II (Ang II)-treated H9C2 cells were used to evaluate the effects of HDAC5 inhibition with LMK235 on ventricular remodeling and cardiac dysfunction. Additionally, the involvement of the extracellular signal-regulated kinase (ERK)/early growth response protein 1 (EGR1) signaling pathway in regulating myocyte enhancer factor 2 A (MEF2A) expression was assessed. Results HDAC5 was upregulated in TAC mice and Ang II-treated H9C2 cells, suggesting its involvement in ventricular remodeling and cardiac dysfunction. LMK235 treatment significantly improved cardiac function in TAC mice and attenuated TAC-induced ventricular remodeling and Ang II-induced H9C2 cell hypertrophy. Mechanically, HDAC5 inhibition activated the ERK/EGR1 signaling pathway. Conclusions Our findings demonstrate that HDAC5 may suppress the activation of ERK/EGR1 signaling to regulate MEF2A expression and therefore participate in cardiac pathophysiology.

Abstract Background Myogenic enhancer transcription factor 2A (MEF2A) is a transcription factor known for its role in controlling skeletal muscle regeneration and metabolic processes, while activating transcription factor 3 (ATF3) is a stress-induced transcription factor that plays a role in modulating metabolic processes, immunity, and oncogenesis. Environmental factors, such as dietary protein, can influence gene expression levels. Insufficient protein intake can negatively affect the metabolic performance of internal organs, leading to the abnormal weight of internal organs. A total of 192 non-sexing crossbred local chickens day-old-chick (DOC) with a completely randomized design (CRD) method of 3 treatments and 8 replicates. Real-time polymerase chain reaction (RT-PCR) is used to measure the gene expression levels. This study aimed to determine the effect of feeding with various protein levels on internal organ weight and gene expression of MEF2A and ATF3 in crossbred local chickens. Result The analysis of treatment revealed that the results were not significantly different (P > 0.05) on gizzard weight and spleen weight. However, it shows a significantly different result (P

The Forkhead box factor 1 (FoxO1) gene plays a vital role in the growth and development of skeletal muscle. In the present study, expression analysis of the bovine FoxO1 gene exhibited the highest expression in longissimus dorsi muscle followed by its expression in adipose tissue. Moreover, high mRNA expression of FoxO1 gene was found in differentiated bovine myoblasts and adipocytes at day 6 of induced differentiation (p < 0.05). The regulatory pattern of the bovine FoxO1 gene was investigated through screening and dual-luciferase activity of the 1.7 kb 5′UTR (untranslated region) within pGL3-basic vector and a core promoter region was explored at (-285/-27) upstream of the transcription start site. The transcription factors (TFs) MEF2A and HOXA5 within the core promoter region (-285/-27) were found as the regulatory cis-acting element. The siRNA interference of the TFs, chromatin immunoprecipitation (ChIP) assay, and site-directed mutation validated that MEF2A and HOXA5 binding occurs in the region -285/-27 bp and performs an essential role in the transcriptional regulation of bovine FoxO1 gene. These findings explored the regulatory network mechanism of the FoxO1 gene in skeletal muscle development and adipogenesis for the bovine breed improvement program. [ABSTRACT FROM AUTHOR]

Renal cell carcinoma (RCC) is the most aggressive subtype of kidney tumour with a poor prognosis and an increasing incidence rate worldwide. Brusatol, an essential active ingredient derived from Brucea javanica, exhibits potent antitumour properties. Our study aims to explore a novel treatment strategy for RCC patients. We predicted 37 molecular targets of brusatol based on the structure of brusatol, and MEF2A (Myocyte Enhancer Factor 2A) was selected as our object through bioinformatic analyses. We employed various experimental techniques, including RT‐PCR, western blot, CCK8, colony formation, immunofluorescence, wound healing, flow cytometry, Transwell assays and xenograft mouse models, to investigate the impact of MEF2A on RCC. MEF2A expression was found to be reduced in patients with RCC, indicating a close correlation with MEF2A deubiquitylation. Additionally, the protective effects of brusatol on MEF2A were observed. The overexpression of MEF2A inhibits RCC cell proliferation, invasion and migration. In xenograft mice, MEF2A overexpression in RCC cells led to reduced tumour size compared to the control group. The underlying mechanism involves the inhibition of RCC cell proliferation, invasion, migration and epithelial‐mesenchymal transition (EMT) through the modulation of Wnt/β‐catenin signalling. Altogether, we found that MEF2A overexpression inhibits RCC progression by Wnt/β‐catenin signalling, providing novel insight into diagnosis, treatment and prognosis for RCC patients. [ABSTRACT FROM AUTHOR]

Background: This study aimed to investigate the role of histone deacetylase 5 (HDAC5) in ventricular remodeling and explore the therapeutic potential of the HDAC5 inhibitor LMK235. Methods: A transverse aortic constriction (TAC) mouse model and angiotensin II (Ang II)-treated H9C2 cells were used to evaluate the effects of HDAC5 inhibition with LMK235 on ventricular remodeling and cardiac dysfunction. Additionally, the involvement of the extracellular signal-regulated kinase (ERK)/early growth response protein 1 (EGR1) signaling pathway in regulating myocyte enhancer factor 2 A (MEF2A) expression was assessed. Results: HDAC5 was upregulated in TAC mice and Ang II-treated H9C2 cells, suggesting its involvement in ventricular remodeling and cardiac dysfunction. LMK235 treatment significantly improved cardiac function in TAC mice and attenuated TAC-induced ventricular remodeling and Ang II-induced H9C2 cell hypertrophy. Mechanically, HDAC5 inhibition activated the ERK/EGR1 signaling pathway. Conclusions: Our findings demonstrate that HDAC5 may suppress the activation of ERK/EGR1 signaling to regulate MEF2A expression and therefore participate in cardiac pathophysiology. [ABSTRACT FROM AUTHOR]

Myocyte enhancer factor 2A (MEF2A) is a member of the myocyte enhancer factor 2 family. MEF2A is widely distributed in various tissues and organs and participates in various physiological processes. This study aimed to investigate the effect of MEF2A expression on the proliferation and apoptosis of bovine myoblasts. CCK8, ELISA, cell cycle, and apoptosis analyses were conducted to assess cell status. In addition, the mRNA expression levels of genes associated with bovine myoblast proliferation and apoptosis were evaluated using RT-qPCR. The results showed that the upregulation of MEF2A mRNA promoted the proliferation rate of myoblasts, shortened the cycle process, and increased the anti-apoptotic rate. Furthermore, the RT-qPCR results showed that the upregulation of MEF2A mRNA significantly increased the cell proliferation factors MyoD1 and IGF1, cell cycle factors CDK2 and CCNA2, and the apoptotic factors Bcl2 and BAD (p < 0.01). These results show that the MEF2A gene can positively regulate myoblast proliferation and anti-apoptosis, providing a basis for the analysis of the regulatory mechanism of the MEF2A gene on bovine growth and development. [ABSTRACT FROM AUTHOR]

Cell regulatory networks are the determinants of cellular homeostasis. Any alteration to these networks results in the disturbance of cellular homeostasis and induces cells towards different fates. Myocyte enhancer factor 2A (MEF2A) is one of four members of the MEF2 family of transcription factors (MEF2A-D). MEF2A is highly expressed in all tissues and is involved in many cell regulatory networks including growth, differentiation, survival and death. It is also necessary for heart development, myogenesis, neuronal development and differentiation. In addition, many other important functions of MEF2A have been reported. Recent studies have shown that MEF2A can regulate different, and sometimes even mutually exclusive cellular events. How MEF2A regulates opposing cellular life processes is an interesting topic and worthy of further exploration. Here, we reviewed almost all MEF2A research papers published in English and summarized them into three main sections: 1) the association of genetic variants in MEF2A with cardiovascular disease, 2) the physiopathological functions of MEF2A, and 3) the regulation of MEF2A activity and its regulatory targets. In summary, multiple regulatory patterns for MEF2A activity and a variety of co-factors cause its transcriptional activity to switch to different target genes, thereby regulating opposing cell life processes. The association of MEF2A with numerous signaling molecules establishes a central role for MEF2A in the regulatory network of cellular physiopathology. [ABSTRACT FROM AUTHOR]

Background: Myocardial infarction, a coronary heart disease, is a serious hazard to human health. Cardiomyocyte oxidative stress and apoptosis have been considered as the main causes of myocardial infarction. Here, we aimed to investigate the role of miR-615-3p in oxidative stress and apoptosis of human cardiomyocytes. Methods: Reverse transcription-quantitative polymerase chain reaction was performed to determine miR-615-3p or MEF2A expression in human cardiomyocytes. Apoptosis and viability of human cardiomyocytes were assessed by flow cytometry analysis and CCK-8 assay. In addition, the contents of malondialdehyde, reactive oxygen species, and superoxide dismutase were detected by corresponding commercial kits. The binding of miR-615-3p and MEF2A in human cardiomyocytes was examined by luciferase reporter assay. Results: Hypoxia/reoxygenation treatment downregulated the expression level of miR‐615-3p in human cardiomyocytes. Overexpressing miR-615-3p increased human cardiomyocyte viability and decreased human cardiomyocyte apoptosis. Moreover, miR-615-3p mimics suppressed oxidative stress in hypoxia/reoxygenation-stimulated human cardiomyocytes. MEF2A was confirmed as a target gene of miR-615-3p and was highly expressed in hypoxia/reoxygenation-stimulated human cardiomyocytes, and its upregulation partially reversed the influence of miR-615-3p mimics on oxidative stress and apop-tosis of human cardiomyocytes. Moreover, miR-615-3p inactivated the P13K/Akt pathway by inhibiting MEF2A. Conclusions: Overexpression of miR-615-3p protects human cardiomyocytes from oxida-tive stress injury by targeting MEF2A via the PI3K/Akt signaling.

Abstract Background Epigenetic reprogramming is involved in multiple steps of human cancer evolution and is mediated by a variety of chromatin-modifying enzymes. Specifically, the histone lysine methyltransferase KMT2D is among the most frequently mutated genes in oral squamous cell carcinoma (OSCC). However, the mechanisms by which KMT2D affects the development of OSCC remain unclear. Results In the present study, we found that the expression of KMT2D was elevated in OSCC compared to paracancerous specimens and was correlated with a more advanced tumor grade. More importantly, knockdown of KMT2D impaired their reconstitution in patient-derived organoids and decreased the expression of CD133 and β-catenin in OSCC cells. In in vitro and in vivo models, knockdown of KMT2D reduced the colony formation, migration and invasion abilities of OSCC cells and delayed tumor growth. Mechanistically, the dual-luciferase reporter and co-immunoprecipitation assays in two individual OSCC cell lines indicated that KMT2D may cooperate with MEF2A to promote the transcription activity of CTNNB1, thereby enhancing WNT signaling. Conclusion The upregulation of KMT2D contributes to stem-like properties in OSCC cells by sustaining the MEF2A-mediated transcriptional activity of CTNNB1.

Interactions of transcriptional corepressors such as histone deacetylase 7 (HDAC7), a class IIa HDAC, with myocyte enhancer factor-2 (MEF2) regulate MEF2 activity. Despite previous investigations exploring interactions between HDAC7 and MEF2, a detailed characterization of the HDAC7-MEF2 functional complex is still lacking. Herein, we first modeled the structure of the HDAC7-MEF2A complex and investigated the inter-protein interactions using all-atom molecular dynamics (MD) simulations. We identified specific amino acids within HDAC7 and MEF2A that participate in interactions such as salt bridges, hydrogen bonds, and hydrophobic interactions. Our results reveal a salt bridge formed between LYS96(HDAC7) and ASP63(MEF2A). Our analysis also predicted formations of reliable hydrogen bonds between SER82(HDAC7) and ASP63(MEF2A) as well as LYS96(HDAC7) and ASP63(MEF2A). In addition, clustering of hydrophobic residues at the interface contributes in stabilizing the HDAC7-MEF2A complex. Results from multiple sequence alignment show that most of the HDAC7 residues that are predicted to associate with MEF2A are conserved in at least three class IIa HDACs and all predicted residues in MEF2A are conserved in MEF2s. We also found that the association of DNA to MEF2A has no significant effect on HDAC7-MEF2A interactions. Our results may also provide useful insights into the interactions between other class IIa HDACs and MEF2s.

Cisplatin (DDP) resistance represents a pivotal contributing factor to chemotherapy failure and adverse patient outcomes in gastric cancer (GC). The objective of the present study was to investigate the roles and underlying mechanisms of myocyte enhancer factor 2A (MEF2A) in DDP resistance in GC. GC cell line AGS and MKN-45 cells were applied to construct DDP-resistant cells. CCK-8, colony formation, and flow cytometry methods were validated for determining the IC50 value of DDP and cell survival of GC cells. qRT-PCR and western blotting analysis quantified the molecular levels at mRNA and protein, respectively. Chromatin immunoprecipitation and dual-luciferase assays validated the molecular relationship between MEF2A and NF-κB inhibitor alpha (NFKBIA). Roles of MEF2A in in vivo were performed employing a xenograft model. The results showed that NFKBIA was greatly decreased in DDP-resistant AGS and MKN-45 cells compared to their respective parental cells. Increasing NFKBIA expression impaired the IC50 value of DDP and cell survival in DDP-resistant cells, while these alterations were rescued upon TNF-α treatment. Mechanistically, MEF2A acts as a transcriptional activator of NFKBIA, which led to the reduction of phosphorylation of p65 and cytoplasmic retention. Moreover, MEF2A overexpression promoted the sensitivity of GC cells to DDP and tumor growth, whereas these effects were partially reversed by NFKBIA silence. Collectively, MEF2A mitigated the DDP resistance in GC cells by modulatory actions on the NFKBIA/NF-κB signaling, shedding light on MEF2A/NFKBIA might be a promising intervention target for improving DDP resistance in GC., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Seminoma is the most common subtype of testicular germ cell tumor, with an increasing incidence worldwide. Clusterin (CLU) expression was found to be downregulated in testicular seminoma in our previous study. We now expanded the sample size, and further indicated that CLU expression correlates with tumor stage. Tcam-2 cell line was used to investigate the CLU function in testicular seminoma, and CLU was found to inhibit the proliferation and metastasis abilities. Besides, extracellular matrix protein COL15a1 was demonstrated as the downstream of CLU to affect the epithelial-mesenchymal transition (EMT) process via competitively binding to DDR1 with COL1A1 and inhibiting the phosphorylation of PYK2. MEF2A was found to interact with CLU and bind to the promoter of COL15a1 and so upregulate its expression. This is the first study using testicular xenografts in situ to simulate testicular seminoma metastatic and proliferative capacities. In conclusion, CLU acts as a tumor suppressor to inhibit the metastasis of testicular seminoma by interacting with MEF2A to upregulate COL15a1 and blocking the EMT process.

Hyperthyroidism can potentiate arrhythmias and cardiac hypertrophy, whereas Ca2+/calmodulin-dependent kinase II (CaMKII) promotes maladaptive myocardial remodeling. However, it remains unclear whether CaMKII contributes to the progression of hyperthyroid heart disease (HHD). This study demonstrated that CaMKII inhibition can relieve adverse myocardial remodeling and reduce sinus tachycardia, isoproterenol-induced atrial fibrillation, and ventricular arrhythmias in hyperthyroid mice with preserved heart function. Hyperthyroid cardiac hypertrophy was promoted by CaMKII upregulation-induced HDAC4/MEF2a activation. Briefly, CaMKII inhibition benefits HHD management greatly in mice by preventing arrhythmias and maladaptive remodeling. • Hyperthyroid heart disease (HHD) was developed in mice by T4 administration. • HHD was characterized by tachyarrhythmias and adverse myocardial remodeling. • T4 promoted CaMKII expression to derepress HDAC4/MEF2a for HHD progression. • CaMKII inhibition ameliorated HHD greatly and is a promising treatment target. [ABSTRACT FROM AUTHOR]

Mitochondrial ORF of the 12S rRNA type-c (MOTS-c) as an AMPK agonist can regulate the expression of adaptive nuclear genes to promote cell homeostasis. However, the investigation of MOTS-c in hepatocellular carcinoma (HCC) is insufficient. This study aims to reveal the role of MOTS-c on HCC cell apoptosis. Huh7 and HCCLM3 cells were incubated with MOTS-c under a hypoxic condition. MOTS-c levels were quantified by enzyme-linked immunosorbent assay in the peripheral blood of HCC patients and healthy controls. Cell viability was detected by 3-(4,5-Dimethylthazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell apoptosis was investigated by flow cytometry and Tunel assay. Protein expression was detected by western blotting or immunohistochemistry assay. Dual-luciferase reporter assay and chromatin immunoprecipitation assay were performed to identify the association among myocyte enhancer factor 2A (MEF2A), death receptor 4 (DR4) and DR5. A tumor-bearing nude mouse model was conducted to assess the effect of MOTS-c on HCC tumor formation in vivo. MOTS-c levels in the peripheral blood of HCC patients were significantly lower compared to healthy individuals. MOTS-c promoted HCC cell apoptosis under hypoxia conditions. Hypoxia stimulation decreased the protein expression of MEF2A, DR4, DR5, fas-associating via death domain (FADD) and caspase-8, while these effects were attenuated after MOTS-c treatment. MOTS-c induced TRAIL-induced apoptosis of HCC cells by activating MEF2A through the phosphorylation of AMPK under hypoxia treatment. In addition, MEF2A transcriptionally up-regulated DR4 and DR5. MOTS-c activated MEF2A to regulate DR4 and DR5 expression, further mediating TRAIL-induced apoptosis. Further, MOTS-c treatment relieved hypoxia-induced tumor growth in vivo. MOTS-c relieved hypoxia-induced HCC cell resistance to TRAIL-caused apoptosis by activating MEF2A. [Display omitted] • MOTS-c promoted the apoptosis of HCC cells after hypoxia treatment. • MEF2A targeted DR4 and DR5 in HCC cells. • MOTS-c relieved HCC cell resistance to TRAIL-induced apoptosis under hypoxia by activating MEF2A. • MOTS-c inhibited HCC tumor formation in vivo. [ABSTRACT FROM AUTHOR]

Chemotherapeutic resistance is a major obstacle to the effectiveness of cisplatin-based chemotherapy for gastric cancer (GC), leading to treatment failure and poor survival rates. However, the underlying mechanisms are not fully understood. Our study demonstrated that the transcription factor myocyte enhancer factor 2A (MEF2A) plays a role in chemotherapeutic drug resistance by regulating the transcription of PGC1α and KEAP1, promoting mitochondrial biogenesis. It was found that increased MEF2A expression is linked with poor prognosis, cisplatin insensitivity, and mitochondrial function in GC. MEF2A overexpression significantly decreases GC cell sensitivity in vitro and in vivo , while MEF2A knockdown enhances the sensitivity to cisplatin. Mechanistically, MEF2A activates the transcription of PGC1α, leading to increased mitochondrial biogenesis. In addition, MEF2A inhibits KEAP1 transcription, reduces NRF2 ubiquitination degradation, and activates the KEAP1/NRF2 signaling pathway, which modulates the reactive oxygen species level. The present study identifies MEF2A as a new critical oncogene involved in GC chemoresistance, suggesting a novel therapeutic target for GC. [Display omitted] • Highly expressed MEF2A is associated with poor prognosis in gastric cancer. • MEF2A inhibits cisplatin sensitivity in vivo and in vitro. • MEF2A transcription activates PGC1α to promote mitochondrial biogenesis. • MEF2A transcriptional inhibition of KEAP1 leads to abnormal KEAP1/NRF2 signaling pathway. [ABSTRACT FROM AUTHOR]

Recent discoveries have revealed remarkable complexity within olfactory sensory neurons (OSNs), including the existence of two OSN populations based on the expression of Cd36. However, the regulatory mechanisms governing this cellular diversity in the same cell type remain elusive. Here, we show the preferential expression of 79 olfactory receptors in Cd36 + OSNs and the anterior projection characteristics of Cd36 + OSNs, indicating the non-randomness of Cd36 expression. The integrated analysis of single-cell RNA sequencing (scRNA-seq) and scATAC-seq reveals that the differences in Cd36 +/− OSNs occur at the immature OSN stage, with Mef2a and Hdac9 being important regulators of developmental divergence. We hypothesize that the absence of Hdac9 may affect the activation of Mef2a , leading to the up-regulation of Mef2a target genes, including teashirt zinc finger family member 1 (Tshz1), in the Cd36 + OSN lineage. We validate that Tshz1 directly promotes Cd36 expression through enhancer bindings. Our study unravels the intricate regulatory landscape and principles governing cellular diversity in the olfactory system. [Display omitted] • A subpopulation of olfactory sensory neurons (OSNs) characterized by Cd36 expression • Cd36 + OSNs exhibit unique transcriptome, chromatin, and spatial patterns • Differences in Cd36 + OSNs emerge during the immature OSNs stage with OR selection • Mef2a and Tshz1 contribute to the regulation of cellular difference in Cd36 + OSNs Yang et al. utilized scRNA and scATAC sequencing approaches to characterize the cellular diversity of olfactory sensory neurons (OSNs). The study reveals a distinct OSN subpopulation characterized by CD36 receptor expression, elucidating the regulatory landscape and potential transcription factors that govern these differences. [ABSTRACT FROM AUTHOR]

Background: Epigenetic reprogramming is involved in multiple steps of human cancer evolution and is mediated by a variety of chromatin-modifying enzymes. Specifically, the histone lysine methyltransferase KMT2D is among the most frequently mutated genes in oral squamous cell carcinoma (OSCC). However, the mechanisms by which KMT2D affects the development of OSCC remain unclear. Results: In the present study, we found that the expression of KMT2D was elevated in OSCC compared to paracancerous specimens and was correlated with a more advanced tumor grade. More importantly, knockdown of KMT2D impaired their reconstitution in patient-derived organoids and decreased the expression of CD133 and β-catenin in OSCC cells. In in vitro and in vivo models, knockdown of KMT2D reduced the colony formation, migration and invasion abilities of OSCC cells and delayed tumor growth. Mechanistically, the dual-luciferase reporter and co-immunoprecipitation assays in two individual OSCC cell lines indicated that KMT2D may cooperate with MEF2A to promote the transcription activity of CTNNB1, thereby enhancing WNT signaling. Conclusion: The upregulation of KMT2D contributes to stem-like properties in OSCC cells by sustaining the MEF2A-mediated transcriptional activity of CTNNB1. [ABSTRACT FROM AUTHOR]

Skeletal muscle differentiation is a highly coordinated process that involves many cellular signaling pathways and microRNAs (miRNAs). A group of muscle-specific miRNAs has been reported to promote myogenesis by suppressing key signaling pathways for cell growth. However, the functional role and regulatory mechanism of most non-muscle-specific miRNAs with stage-specific changes during differentiation are largely unclear. Here, we describe the functional characterization of miR-101a/b, a pair of non-muscle-specific miRNAs that show the largest change among a group of transiently upregulated miRNAs during myogenesis in C2C12 cells. The overexpression of miR-101a/b inhibits myoblast differentiation by suppressing the p38/MAPK, Interferon Gamma, and Wnt pathways and enhancing the C/EBP pathway. Mef2a, a key protein in the p38/MAPK pathway, was identified as a direct target of miR-101a/b. Interestingly, we found that the long non-coding RNA (lncRNA) Malat1, which promotes muscle differentiation, interacts with miR-101a/b, and this interaction competes with Mef2a mRNA to relieve the inhibition of the p38/MAPK pathway during myogenesis. These results uncovered a "braking" role in differentiation of transiently upregulated miRNAs and provided new insights into the competing endogenous RNA (ceRNA) regulatory mechanism in myoblast differentiation and myogenesis. [ABSTRACT FROM AUTHOR]

Background: Cholangiocytes are primary targets in chronic cholestatic liver diseases. Myocyte enhancer factor 2A (MEF2A) is a transcription factor with a crucial role in some fibrogenic diseases. However, whether it contributes to cholestatic liver fibrosis is still obscure. Methods: A bile duct–ligated (BDL) mouse model was established to detect MEF2A expression during cholestatic liver fibrosis. In addition, human intrahepatic biliary epithelial cells (HIBECs) were transfected with lentivirus-expressing shMEF2A (LV-shMEF2A) to regulate the expression of MEF2A in vitro. Biomarkers of epithelial to mesenchymal transition (EMT), senescence, and fibrogenesis were evaluated using various assays: Quantitative real-time polymerase chain reaction (qRT-PCR), western blotting, senescence-associated β-galactosidase (SA-β-gal), and immunofluorescence. Furthermore, MEF2A expression and cytoplasm translocation induced by transforming growth factor β1 (TGF-β1) in HIBECs were determined by qRT-PCR, western blotting, and immunofluorescence. The expression of TGF-β1-induced MEF2A, EMT, senescence, and fibrosis markers inhibited by p38 MAPK signaling were evaluated by western blotting. Finally, the peripheral blood from primary biliary cholangitis (PBC) patients and healthy controls (HCs) was collected to analyze expression of MEF2A using Enzyme-linked immunosorbent assay (ELISA). Results: We found that MEF2A expression increased in liver tissues of BDL mice, and positively related to the extent of fibrosis. Silencing MEF2A in HIBECs restrained TGF-β1-induced EMT, senescence, and fibrotic reaction. Moreover, TGF-β1 enhanced the expression of MEF2A and induced its cytoplasm translocation in a concentration- and time-dependent manner, partially through interacting with p38 MAPK. The expression of MEF2A was also higher in the serum of PBC patients than in HCs, and positively correlated with fibrosis degree. Conclusions: Our study demonstrates that MEF2A is a central mediator linking TGF-β1-induced EMT and senescence in HIBECs. We propose it as a novel biomarker of fibrogenesis in cholestatic liver fibrosis. We also suggest inhibiting MEF2A as a potential strategy in treating cholestatic liver fibrosis.

Coronary artery disease (CAD) and its main complication, myocardial infarction (MI), is a complex disease caused by environmental and genetic factors and their interaction. Family-based linkage analysis and genome-wide association studies have indicated many of genetic variations related to CAD and MI in recent years. Some are in the coding sequence, which mediates the coding protein, while others are in the non-coding region, which affects the expression of adjacent genes and forms differential gene expression. These variants and differential expressions will have varying degrees of impact on the development of the cardiovascular system and normal heart electrical activity function, subsequently leading to CAD and MI. Among these affected genes, some Transcription Factors (TFs), as important means of transcriptional regulation, have a key role in the pathogenesis of coronary artery disease and myocardial infarction. The GATAs binding protein 2 (GATA2) enhances monocyte adhesion and promoted vessel wall permeabilization through vascular EC adhesion molecule 1 (VCAM-1) upregulation, further revealing its atherosclerosis-promoting role. Myocyte enhancer factor 2 (MEF2) has a role in fostering many functions of the atherosclerotic endothelium and is a potential therapeutic target for atherosclerosis, thrombosis, and inflammation. Nuclear factor-kappa B (NF-κB) is an important promoter of vascular endothelial growth factor (VEGF)-driven angiogenesis, and its pathway has a key role in atherosclerosis-related complications such as angiogenesis, inflammation, apoptosis, and immune effects. Activating transcription factor 3 (ATF3) may be a novel prognostic biomarker and therapeutic target for atherosclerosis. The important role of signal transducer and activator of transcription 3 (STAT3) (especially in mitochondria) in endothelial cells (EC) dysfunction, inflammation, macrophage polarization and immunity in atherosclerosis.

Clinical data mining and bioinformatics analysis can be employed effectively to elucidate the function and underlying mechanisms of the gene of interest. Here, we have proposed a framework for the identification and validation of independent biomarkers in human cancer and for mechanistic profiling using gene sets enrichment analysis and pathway analysis. This is followed by validation with in vitro experiments. Using this framework to analyze the clinical relevance of SEC23A, we have discovered the prognostic potential of SEC23A in different cancers and identified SEC23A as an independent prognostic factor for poor prognosis in bladder cancer, which implicates SEC23A, for the first time, as an oncogene. Bioinformatic analyses have elucidated an association between SEC23A expression and the upregulation of the MAPK signaling pathway. Using the T24 human bladder cell line, we confirmed that knockdown of SEC23A expression could effectively impact the MAPK signaling pathway. Further, through PCR verification, we showed that MEF2A, one of the key genes of the MAPK signaling pathway, might be a downstream factor of the SEC23A gene.

Clinical data mining and bioinformatics analysis can be employed effectively to elucidate the function and underlying mechanisms of the gene of interest. Here, we have proposed a framework for the identification and validation of independent biomarkers in human cancer and for mechanistic profiling using gene sets enrichment analysis and pathway analysis. This is followed by validation with in vitro experiments. Using this framework to analyze the clinical relevance of SEC23A, we have discovered the prognostic potential of SEC23A in different cancers and identified SEC23A as an independent prognostic factor for poor prognosis in bladder cancer, which implicates SEC23A, for the first time, as an oncogene. Bioinformatic analyses have elucidated an association between SEC23A expression and the upregulation of the MAPK signaling pathway. Using the T24 human bladder cell line, we confirmed that knockdown of SEC23A expression could effectively impact the MAPK signaling pathway. Further, through PCR verification, we showed that MEF2A, one of the key genes of the MAPK signaling pathway, might be a downstream factor of the SEC23A gene. [ABSTRACT FROM AUTHOR]

Abstract The function of nuclear receptor corepressor 1 (NCoR1) in cardiomyocytes is unclear, and its physiological and pathological implications are unknown. Here, we found that cardiomyocyte‐specific NCoR1 knockout (CMNKO) mice manifested cardiac hypertrophy at baseline and had more severe cardiac hypertrophy and dysfunction after pressure overload. Knockdown of NCoR1 exacerbated whereas overexpression mitigated phenylephrine‐induced cardiomyocyte hypertrophy. Mechanistic studies revealed that myocyte enhancer factor 2a (MEF2a) and MEF2d mediated the effects of NCoR1 on cardiomyocyte hypertrophy. The receptor interaction domains (RIDs) of NCoR1 interacted with MEF2a to repress its transcriptional activity. Furthermore, NCoR1 formed a complex with MEF2a and class IIa histone deacetylases (HDACs) to suppress hypertrophy‐related genes. Finally, overexpression of RIDs of NCoR1 in the heart attenuated cardiac hypertrophy and dysfunction induced by pressure overload. In conclusion, NCoR1 cooperates with MEF2 and HDACs to repress cardiac hypertrophy. Targeting NCoR1 and the MEF2/HDACs complex may be an attractive therapeutic strategy to tackle pathological cardiac hypertrophy.

Alzheimer’s disease (AD) is a neurodegenerative disease characterized by amyloid plaques and neurofibrillary tangles which significantly affects people’s life quality. Recently, AD has been found to be closely related to autophagy. The aim of this study was to identify autophagy-related genes associated with the pathogenesis of AD from multiple types of microarray and sequencing datasets using bioinformatics methods and to investigate their role in the pathogenesis of AD in order to identify novel strategies to prevent and treat AD. Our results showed that the autophagy-related genes were significantly downregulated in AD and correlated with the pathological progression. Furthermore, enrichment analysis showed that these autophagy-related genes were regulated by the transcription factor myocyte enhancer factor 2A (MEF2A), which had been confirmed using si-MEF2A. Moreover, the single-cell sequencing data suggested that MEF2A was highly expressed in microglia. Methylation microarray analysis showed that the methylation level of the enhancer region of MEF2A in AD was significantly increased. In conclusion, our results suggest that AD related to the increased methylation level of MEF2A enhancer reduces the expression of MEF2A and downregulates the expression of autophagy-related genes which are closely associated with AD pathogenesis, thereby inhibiting autophagy.

Alzheimer's disease (AD) is a neurodegenerative disease characterized by amyloid plaques and neurofibrillary tangles which significantly affects people's life quality. Recently, AD has been found to be closely related to autophagy. The aim of this study was to identify autophagy-related genes associated with the pathogenesis of AD from multiple types of microarray and sequencing datasets using bioinformatics methods and to investigate their role in the pathogenesis of AD in order to identify novel strategies to prevent and treat AD. Our results showed that the autophagy-related genes were significantly downregulated in AD and correlated with the pathological progression. Furthermore, enrichment analysis showed that these autophagy-related genes were regulated by the transcription factor myocyte enhancer factor 2A (MEF2A), which had been confirmed using si-MEF2A. Moreover, the single-cell sequencing data suggested that MEF2A was highly expressed in microglia. Methylation microarray analysis showed that the methylation level of the enhancer region of MEF2A in AD was significantly increased. In conclusion, our results suggest that AD related to the increased methylation level of MEF2A enhancer reduces the expression of MEF2A and downregulates the expression of autophagy-related genes which are closely associated with AD pathogenesis, thereby inhibiting autophagy. [ABSTRACT FROM AUTHOR]

Long noncoding RNA MIR155HG exerts important effects in the progression of multiple diseases. This study investigated the functions of MIR155HG in sepsis development. Blood samples were collected from 28 patients with sepsis and 28 without sepsis. The murine cardiac muscle cell line (HL-1) and macrophage cell line (RAW 264.7) treated with lipopolysaccharide (LPS) were used as the in vitro sepsis models. The levels of MIR155HG, miR-194-5p, and MEF2A were determined using real-time-quantitative polymerase chain reaction. Cell counting kit-8 and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assays were used to assess cell viability and apoptosis, respectively. The association between miR-194-5p and MIR155HG or MEF2A was confirmed using a dual-luciferase reporter assay. The levels of inflammatory cytokines were detected using enzyme-linked immunosorbent assay (ELISA). In this study, we demonstrated that MIR155HG expression was significantly increased in sepsis blood samples, RAW 264.7, and HL-1 cells treated with LPS. Silencing of MIR155HG promoted cell viability and obstructed cell apoptosis and inflammation of RAW 264.7 and HL-1 cells treated with LPS. MiR-194-5p depletion abrogated cell viability promotion and suppressive effect on cell apoptosis and inflammation caused by MIR155HG knockdown. In addition, MIR155HG upregulated MEF2A through interaction with miR-194-5p. Finally, rescue assays indicated that MEF2A overexpression abolished the inhibitory effect on sepsis progression induced by MIR155HG deletion. In conclusion, MIR155HG promotes sepsis progression in an in vitro sepsis model by modulating the miR-194-5p/MEF2A axis. This discovery provides a promising biomarker for sepsis therapy. [ABSTRACT FROM AUTHOR]

The miR-129 family is widely reported as tumor repressors, although their roles in skeletal muscle have not been fully investigated. Here, the function and mechanism of miR-129-5p in skeletal muscle, a member of the miR-129 family, were explored using C2C12 cell line. Our study showed that miR-129-5p was widely detected in mouse tissues, with the highest expression in skeletal muscle. Gain- and loss-of-function study showed that miR-129-5p could negatively regulate myogenic differentiation, indicated by reduced ratio of MyHC-positive myofibers and repressed expression of myogenic genes, such as MyoD, MyoG, and MyHC. Furthermore, miR-129-5p was more enriched in fast extensor digitorum longus (EDL) than in slow soleus (SOL). Enhanced miR-129-5p could significantly reduce the expression of mitochondrial cox family, together with that of MyHC I, and knockdown of miR-129-5p conversely increased the expression of cox genes and MyHC I. Mechanistically, miR-129-5p directly targeted the 30-UTR of Mef2a, which was suppressed by miR-129-5p agomir at both mRNA and protein levels in C2C12 cells. Moreover, overexpression of Mef2a could rescue the inhibitory effects of miR-129-5p on the expression of myogenic factors and MyHC I. Collectively, our data revealed that miR-129-5p is a negative regulator of myogenic differentiation and slow fiber gene expression, thus affecting body metabolic homeostasis. [ABSTRACT FROM AUTHOR]

Dilated cardiomyopathy (DCM) represents the most frequent form of cardiomyopathy, leading to heart failure, cardiac arrhythmias and death. Accumulating evidence convincingly demonstrates the crucial role of genetic defects in the pathogenesis of DCM, and over 100 culprit genes have been implicated with DCM. However, DCM is of substantial genetic heterogeneity, and the genetic determinants underpinning DCM remain largely elusive. Whole-exome sequencing and bioinformatical analyses were implemented in a consanguineous Chinese family with DCM. A total of 380 clinically annotated control individuals and 166 more DCM index cases then underwent Sanger sequencing analysis for the identified genetic variation. The functional characteristics of the variant were delineated by utilizing a dual-luciferase assay system. A heterozygous variation in the MEF2A gene (encoding myocyte enhancer factor 2A, a transcription factor pivotal for embryonic cardiogenesis and postnatal cardiac adaptation), NM_001365204.1: c.718G>T; p. (Gly240*), was identified, and verified by Sanger sequencing to segregate with autosome-dominant DCM in the family with complete penetrance. The nonsense variation was neither detected in 760 control chromosomes nor found in 166 more DCM probands. Functional analyses revealed that the variant lost transactivation on the validated target genes MYH6 and FHL2, both causally linked to DCM. Furthermore, the variation nullified the synergistic activation between MEF2A and GATA4, another key transcription factor involved in DCM. The findings firstly indicate that MEF2A loss-of-function variation predisposes to DCM in humans, providing novel insight into the molecular mechanisms of DCM and suggesting potential implications for genetic testing and prognostic evaluation of DCM patients. [ABSTRACT FROM AUTHOR]

Background: Porcine skeletal muscle development is pivotal for improving meat production. TP63 , a transcription factor, regulates vital cellular processes, yet its role in skeletal muscle proliferation is unclear., Methods: The effects of TP63 on skeletal muscle cell viability and proliferation were investigated using both mouse and porcine skeletal muscle myoblasts. Selective sweep analysis in Western pigs identified TP63 as a potential candidate gene for skeletal muscle development. The correlation between TP63 overexpression and cell proliferation was assessed using quantitative real-time PCR (RT-qPCR) and 5-ethynyl-2'-deoxyuridine (EDU)., Results: The study revealed a positive correlation between TP63 overexpression and skeletal muscle cell proliferation. Bioinformatics analysis predicted an interaction between MEF2A, another transcription factor, and the mutation site of TP63 . Experimental validation through dual-luciferase assays confirmed that a candidate enhancer SNP could influence MEF2A binding, subsequently regulating TP63 expression and promoting skeletal muscle cell proliferation., Conclusion: These findings offer experimental evidence for further exploration of skeletal muscle development mechanisms and the advancement of genetic breeding strategies aimed at improving meat production traits., 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 © 2024 Chen, Wang, Qu, Song, Tang, Li, Cao and Yi.)

Hibernating brown bears, Ursus arctos, undergo extended periods of inactivity and yet these large hibernators are resilient to muscle disuse atrophy. Physiological characteristics associated with atrophy resistance in bear muscle have been examined (e.g., muscle mechanics, neural activity) but roles for molecular signaling/regulatory mechanisms in the resistance to muscle wasting in bears still require investigation. Using quantitative reverse transcription PCR (RT‐qPCR), the present study characterized the responses of 36 microRNAs linked with development, metabolism, and regeneration of skeletal muscle, in the vastus lateralis of brown bears comparing winter hibernating and summer active animals. Relative levels of mRNA of selected genes (mef2a, pax7, id2, prkaa1, and mstn) implicated upstream and downstream of the microRNAs were examined. Results indicated that hibernation elicited a myogenic microRNA, or "myomiR", response via MEF2A‐mediated signaling. Upregulation of MEF2A‐controlled miR‐1 and miR‐206 and respective downregulation of pax7 and id2 mRNA are suggestive of responses that promote skeletal muscle maintenance. Increased levels of metabolic microRNAs, such as miR‐27, miR‐29, and miR‐33, may facilitate metabolic suppression during hibernation via mechanisms that decrease glucose uptake and fatty acid oxidation. This study identified myomiR‐mediated mechanisms for the promotion of muscle regeneration, suppression of ubiquitin ligases, and resistance to muscle atrophy during hibernation mediated by observed increases in miR‐206, miR‐221, miR‐31, miR‐23a, and miR‐29b. This was further supported by the downregulation of myomiRs associated with a muscle injury and inflammation (miR‐199a and miR‐223) during hibernation. The present study provides evidence of myomiR‐mediated signaling pathways that are activated during hibernation to maintain skeletal muscle functionality in brown bears. [ABSTRACT FROM AUTHOR]

Metabolic reprogramming in pediatric diffuse midline glioma is driven by gene expression changes induced by the hallmark histone mutation H3K27M, which results in aberrantly permissive activation of oncogenic signaling pathways. Previous studies of diffuse midline glioma with altered H3K27 (DMG-H3K27a) have shown that the RAS pathway, specifically through its downstream kinase, extracellular-signal-related kinase 5 (ERK5), is critical for tumor growth. Further downstream effectors of ERK5 and their role in DMG-H3K27a metabolic reprogramming have not been explored. We establish that ERK5 is a critical regulator of cell proliferation and glycolysis in DMG-H3K27a. We demonstrate that ERK5 mediates glycolysis through activation of transcription factor MEF2A, which subsequently modulates expression of glycolytic enzyme PFKFB3. We show that in vitro and mouse models of DMG-H3K27a are sensitive to the loss of PFKFB3. Multi-targeted drug therapy against the ERK5-PFKFB3 axis, such as with small-molecule inhibitors, may represent a promising therapeutic approach in patients with pediatric diffuse midline glioma. [Display omitted] • ERK5 regulates cell proliferation and glycolysis in DMG-H3K27a • ERK5 mediates glycolysis through PFKFB3 via the MEF2A transcription factor • DMG-H3K27a models are sensitive to PFKFB3 inhibition • Multi-targeted therapy against ERK5-PFKFB3 axis has clinical potential Diffuse midline glioma (DMG-H3K27a) is an aggressive pediatric tumor with poor prognosis and limited therapeutic options. Casillo et al. show that ERK5 modulates expression of glycolytic enzyme PFKFB3 through MEF2A and that DMG-H3K27a is sensitive to PFKFB3 loss. The ERK5-PFKFB3 axis represents a potential therapeutic target for treatment of DMG-H3K27a. [ABSTRACT FROM AUTHOR]

Improving the efficacy of neovascularization is a promising strategy to restore perfusion of ischemic tissues in patients with peripheral arterial disease. The 14q32 microRNA cluster is highly involved in neovascularization. The Mef2a transcription factor has been shown to induce transcription of the microRNAs within this cluster. We inhibited expression of Mef2a using gene-silencing oligonucleotides (GSOs) in an in vivo hind limb ischemia model. Treatment with GSO-Mef2a clearly improved blood flow recovery within 3 days (44% recovery versus 25% recovery in control) and persisted until 14 days after ischemia induction (80% recovery versus 60% recovery in control). Animals treated with GSO-Mef2a showed increased arteriogenesis and angiogenesis in the relevant muscle tissues. Inhibition of Mef2a decreased expression of 14q32 microRNAs miR-329 (p = 0.026) and miR-494 (trend, p = 0.06), but not of other 14q32 microRNAs, nor of 14q32 microRNA precursors. Because Mef2a did not influence 14q32 microRNA transcription, we hypothesized it functions as an RNA-binding protein that influences processing of 14q32 microRNA miR-329 and miR-494. Mef2A immunoprecipitation followed by RNA isolation and rt/qPCR confirmed direct binding of MEF2A to pri-miR-494, supporting this hypothesis. Our study demonstrates a novel function for Mef2a in post-ischemic neovascularization via post-transcriptional regulation of 14q32 microRNAs miR-329 and miR-494.

Abstract While MEF2 transcription factors are well known to cooperate in orchestrating cell fate and adaptive responses during development and adult life, additional studies over the last decade have identified a wide spectrum of genetic alterations of MEF2 in different cancers. The consequences of these alterations, including triggering and maintaining the tumorigenic process, are not entirely clear. A deeper knowledge of the molecular pathways that regulate MEF2 expression and function, as well as the nature and consequences of MEF2 mutations are necessary to fully understand the many roles of MEF2 in malignant cells. This review discusses the current knowledge of MEF2 transcription factors in cancer. [ABSTRACT FROM AUTHOR]

Calpain 3 (Capn3), a skeletal muscle-specific member of the calpain family, executes some non-proteolytic functions besides its role as a Ca 2+ -regulated proteolytic enzyme. Previously, we found that changes in Capn3 expression were linearly correlated with the degree of muscular atrophy following reversible sciatic nerve injury and that knockdown of Capn3 gene expression promoted myoblast differentiation. While the regulation of capn3 gene expression is interesting, transcriptional regulation of Capn3 is still unclear. In the present study, we provided experimental data showing that the myogenic enhancer factor 2A (MEF2A) regulated Capn3 gene expression. Firstly, the luciferase reporter assay and EMSA were performed and showed that ectopic expression of the Mef2a gene could bind to the predicted site of the Capn3 promoter region. Furthermore, in the L6 myoblast differentiation model in vitro, Capn3 gene expression was shown to be positively associated with the level of Mef2a by qRT-PCR, western-blotting, and immunocytochemistry. The Capn3 protein level decreased as MEF2A decreased when induced by Mef2a siRNA transfection in L6 myoblasts. Finally, the results of ChIP indicated that MEF2A occupied the promoter region of the Capn3 gene in rat denervated gastrocnemius muscle tissue. Based on these results, we proposed that MEF2A is a transcriptional regulator for Capn3 gene expression. [ABSTRACT FROM AUTHOR]

Prenatal stress (PS) induces molecular changes that alter neural connectivity, increasing the risk for neuropsychiatric disorders. Here we analyzed —in the hippocampus of adult rats exposed to PS— the epigenetic signature mediating the PS-induced neuroplasticity changes. Furthermore, using cultured hippocampal neurons, we investigated the effects on neuroplasticity of an epigenetic modulator. PS induced significant modifications in the mRNA levels of stress-related transcription factor MEF2A, SUV39H1 histone methyltransferase, and TET1 hydroxylase, indicating that PS modifies gene expression through chromatin remodeling. In in vitro analysis, histone acetylation inhibition with apicidin increased filopodium density, suggesting that the external regulation of acetylation levels might modulate neuronal morphology. These results offer a way to enhance neural connectivity that could be considered to revert PS effects. [ABSTRACT FROM AUTHOR]

Cellular stress in the form of disrupted transcription, loss of organelle integrity, or damage to nucleic acids can elicit inflammatory responses by activating signaling cascades canonically tasked with controlling pathogen infections. These stressors must be kept in check to prevent unscheduled activation of interferon, which contributes to autoinflammation. This study examines the role of the transcription factor myocyte enhancing factor 2A (MEF2A) in setting the threshold of transcriptional stress responses to prevent R-loop accumulation. Increases in R-loops lead to the induction of interferon and inflammatory responses in a DEAD-box helicase 41 (DDX41)-, cyclic GMP-AMP synthase (cGAS)-, and stimulator of interferon genes (STING)-dependent manner. The loss of MEF2A results in the activation of ATM and RAD3-related (ATR) kinase, which is also necessary for the activation of STING. This study identifies the role of MEF2A in sustaining transcriptional homeostasis and highlights the role of ATR in positively regulating R-loop-associated inflammatory responses. [Display omitted] • Loss of MEF2A, not other members of the MEF2 family, promotes STING-dependent inflammation • MEF2A expression prevents the accumulation of R-loops that induce IFN • The RNA:DNA helicase, DDX41, and cGAS are necessary for IFN induction • ATR kinase activity, but not ATM or DNA-PK, is required for STING activation Smith et al. show that depletion of the transcription factor MEF2A leads to R-loop accumulation and DDX41-/cGAS-/STING-dependent inflammatory responses. ATR kinase activity is required to activate STING-dependent inflammation. [ABSTRACT FROM AUTHOR]

Houttuynia cordata Thunb (H cordata), a medicinal plant, has anticancer activity, as it inhibits cell growth and induces cell apoptosis in cancer. However, the potential anti-cancer activity and mechanism of H cordata for human liver cancer cells is not well understood. Recently, we identified hypoxia-inducible factor (HIF)-1A, Forkhead box (FOX)O3, and MEF2A as proapoptotic factors induced by H cordata, suggesting that HIF-1A, FOXO3, and MEF2A contribute to the apoptosis of HepG2 hepatocellular carcinoma cells. FOXO3 transcription factors regulate target genes involved in apoptosis. H cordata significantly increased the mRNA and protein expression of HIF-1A and FOXO3 and stimulated MEF2A expression in addition to increased apoptosis in HepG2 cells within 24 hours. Therefore, we determined the potential role of FOXO3 on apoptosis and on H cordata–induced MEF2A in HepG2 cells. HIF-1A silencing by siRNA attenuated MEF2A and H cordata–mediated FOXO3 upregulation in HepG2 cells. Furthermore, H cordata–mediated MEF2A expression enhanced caspase-3 and caspase-7, which were abolished on silencing FOXO3 with siRNA. In addition, H cordata inhibited growth of human hepatocellular carcinoma xenografts in nude mice. Taken together, our results demonstrate that H cordata enhances HIF-1A/FOXO3 signaling, leading to MEF2A upregulation in HepG2 cells, and in parallel, it disturbs the expression of Bcl-2 family proteins (Bax, Bcl-2, and Bcl-xL), which results in apoptosis. Taken together, these findings demonstrate that H cordata promotes the activation of HIF-1A–FOXO3 and MEF2A pathways to induce apoptosis in human HepG2 hepatocellular carcinoma cells and is, therefore, a promising candidate for antitumor drug development. [ABSTRACT FROM AUTHOR]

Exercise brings changes on the chromatin ensuing the upregulation of many genes that confer protection from type 2 diabetes. In type-2 diabetes, critical genes are down-regulated such as those involved in glucose transport (GLUT4, MEF2A) and also oxidative phosphorylation (NRF-1 and its target genes). Recent reports have shown that NRF-1 not only regulate mitochondrial oxidative genes but also controls MEF2A, the main transcription factor for glucose transporter, GLUT4. Such dual control of the two pathways by NRF-1 place it as critical gene in the design of therapeutic modalities much needed to cure or better manage type 2 diabetes. Although it is known that NRF-1 controls these dual pathways (glucose transport and oxidative phosphorylation), the actual molecular mechanisms involved surrounding this regulation remains elusive. NRF-1 itself is regulated through posttranslational modifications (acetylation, methylation and phosphorylation) resulting in enhanced binding to its target genes. This study is therefore aimed at assessing whether CaMKII, a kinase activated by exercise brings about hyper-acetylation of histones in the vicinity of NRF-1 target gene, Mef2a . Five to six weeks old male Wistar rats were used in this study. Chromatin immunoprecipitation (ChIP) assay was used to investigate the extent through which NRF-1 is bound to the Mef2a gene and if this was associated with hyper-acetylation of histones in the region of NRF-1 binding site of the Mef2a gene. Quantitative real time PCR (qPCR) was used to determine the gene expression of MEF2A and NRF-1. Results from this study indicated that exercise-induced CaMKII activation increased hyper-acetylation of histones in the region of NRF-1 binding site on vicinity of Mef2a gene and this was associated with the increased binding of NRF-1 to Mef2a gene. Exercise also increased the expression of NRF-1 and MEF2A genes. Administration of CaMKII inhibitor (KN93) prior to exercise attenuated the observed exercise-induced increase of NRF-1 and MEF2A expressions. In conclusion, this study demonstrated for the first time in our knowledge one mechanism through which NRF-1 regulates MEF2A, pathway critical in glucose transport. [ABSTRACT FROM AUTHOR]

Background: The type X collagen gene ( Col10a1 ) is a signature gene of hypertrophic chondrocytes that are known as the main engine of long bone growth. Multiple transcription factors (TFs), including myocyte enhancer factor 2A (Mef2a), have previously been identified by in silico analysis as potential Col10al gene regulators., Objectives: In this study, we aimed to investigate the correlation between Mef2a and Col10a1 expression and the possible effects on chondrocyte proliferation and hypertrophic differentiation in vitro ., Methods: First, Mef2a expression in proliferating and hypertrophic chondrocytes were detected by quantitative real-time PCR (qRT-PCR) and Western blotting in two chondrocytic models, ATDC5 and MCT cells, as well as in mouse chondrocytes in situ . Transfection with Mef2a small interfering fragments or Mef2a overexpression plasmids in the above chondrocytic models were performed to determine how Mef2a knockdown or overexpression may influence Col10a1 expression. The binding between Mef2a and its putative binding site within the 150 bp Col10a1 cis-enhancer which was evaluated by the dual luciferase reporter assay. The effect of Mef2a on chondrocyte differentiation was determined by examining the chondrogenic marker gene expression by qRT-PCR and by alcian blue, alkaline phosphatase (ALP), and alizarin red staining of the ATDC5 cells stably knocked down by Mef2a., Results: The expression of Mef2a in hypertrophic chondrocytes was significantly higher than that in proliferative chondrocytes in both chondrocytic models as well as in mouse chondrocytes in situ . Interference with Mef2a caused decreased Col10a1 expression, while overexpression of Mef2a upregulated Col10a1. The result of the dual luciferase reporter assay showed that Mef2a enhanced Col10a1 gene enhancer activity via its putative Mef2a binding site. For the staining of ATDC5 stable cell lines, although no significant differences were seen in ALP staining, significantly weaker alcian blue staining intensity was noticed in Mef2a knockdown stable cell lines compared to the control cells at day 21, while slightly weaker alizarin red staining was seen in the stable cell lines at days 14 and 21. Correspondingly, we detected decreased runt-related transcription factor 2 ( Runx2 ), increased SRY-box transcription factor 9 ( Sox9 ), as well as differential expression of other chondrogenic markers in ATDC5 stable cell lines compared with the controls., Conclusions: In conclusion, our results support that Mef2a upregulates Col10a1 expression possibly by interaction with its cis-enhancer. Altered levels of Mef2a affects the expression of chondrogenic marker genes, such as Runx2 and Sox9, but may only play an insignificant role during chondrocyte proliferation and maturation., Competing Interests: None., (AJTR Copyright © 2023.)

Cell regulatory networks are the determinants of cellular homeostasis. Any alteration to these networks results in the disturbance of cellular homeostasis and induces cells towards different fates. Myocyte enhancer factor 2A (MEF2A) is one of four members of the MEF2 family of transcription factors (MEF2A-D). MEF2A is highly expressed in all tissues and is involved in many cell regulatory networks including growth, differentiation, survival and death. It is also necessary for heart development, myogenesis, neuronal development and differentiation. In addition, many other important functions of MEF2A have been reported. Recent studies have shown that MEF2A can regulate different, and sometimes even mutually exclusive cellular events. How MEF2A regulates opposing cellular life processes is an interesting topic and worthy of further exploration. Here, we reviewed almost all MEF2A research papers published in English and summarized them into three main sections: 1) the association of genetic variants in MEF2A with cardiovascular disease, 2) the physiopathological functions of MEF2A, and 3) the regulation of MEF2A activity and its regulatory targets. In summary, multiple regulatory patterns for MEF2A activity and a variety of co-factors cause its transcriptional activity to switch to different target genes, thereby regulating opposing cell life processes. The association of MEF2A with numerous signaling molecules establishes a central role for MEF2A in the regulatory network of cellular physiopathology., Competing Interests: Competing interests All authors declare no conflict of interest., (copyright: © 2022 Liu et al.)

The aim of the present study was to identify the genetic defect responsible for familial coronary artery disease/myocardial infarction (CAD/MI), which exhibited an autosomal dominant pattern of inheritance, in an extended Chinese Han pedigree containing 34 members. Using exome and Sanger sequencing, a novel 6-base pair (bp) 'CAGCCG' deletion in exon 11 of the myocyte enhancer factor 2A (MEF2A) gene was identified, which cosegregated with CAD/MI cases in this family. This 6-bp deletion was not detected in 311 sporadic cases of premature CAD/MI or in 323 unrelated healthy controls. Determination of a genetic risk profile has a key role in understanding the pathogenesis of CAD and MI. Among the reported risk-conferring genes and their variants, mutations in MEF2A have been reported to segregate with CAD/MI in Caucasian families. Causative missense mutations have also been detected in sporadic CAD/MI cases. However, this suggested genetic linkage is controversial, since it could not be confirmed by ensuing studies. The discovery of a novel MEF2A mutation in a Chinese family with premature CAD/MI suggests that MEF2A may have a significant role in the pathogenesis of premature CAD/MI. To better understand this association, further in vitro and in vivo studies are required. [ABSTRACT FROM AUTHOR]

Mesenchymal stem cell (MSC) differentiation is regulated intrinsically by transcription factors and extrinsically by the extracellular matrix. We tested whether matrix metalloproteinase-2 (MMP-2) and its inhibitor TIMP-2, MEF2a and TAZ transcription factors are involved in porcine MSC differentiation towards adipocytes and osteocytes. Flow cytometry and immunofluorescence were used to investigate the expression levels of multipotent cell surface markers CD73 and CD105. Real- time PCR was performed to detect the osteogenic- and adipogenic-specific markers, osteocalcin and aP2, respectively, and to estimate the MMP-2, TIMP-2, MEF2a and TAZ transcript expression levels in three groups of cell, i.e., undifferentiated MSCs, adipocytes (A) and osteocytes (O). We showed that at the transcript level, the differentiation of MSCs towards adipocyte fate may involve MMP-2, TIMP-2 and TAZ. We also show that the differentiation of MSCs toward osteocyte fate may involve TIMP-2, MEF2a and TAZ. Our research provides preliminary data on the possible role of the MMP-2, TIMP-2 and TAZ transcripts in adipogenic differentiation and of the TIMP-2, TAZ and MEF2a transcripts in the osteogenic differentiation of porcine MSCs. We report for the first time the possible involvement of MEF2a in the osteogenesis of porcine MSCs. Our work may provide additional evidence for the MMP-independent function of TIMP-2 during osteogenesis. [ABSTRACT FROM AUTHOR]