BACH1 controls hepatic insulin signaling and glucose homeostasis in mice.

Hepatic insulin resistance is central to the metabolic syndrome. Here we investigate the role of BTB and CNC homology 1 (BACH1) in hepatic insulin signaling. BACH1 is elevated in the hepatocytes of individuals with obesity and patients with non-alcoholic fatty liver disease (NAFLD). Hepatocyte-specific Bach1 deletion in male mice on a high-fat diet (HFD) ameliorates hyperglycemia and insulin resistance, improves glucose homeostasis, and protects against steatosis, whereas hepatic overexpression of Bach1 in male mice leads to the opposite phenotype. BACH1 directly interacts with the protein-tyrosine phosphatase 1B (PTP1B) and the insulin receptor ß (IR-ß), and loss of BACH1 reduces the interaction between PTP1B and IR-ß upon insulin stimulation and enhances insulin signaling in hepatocytes. Inhibition of PTP1B significantly attenuates BACH1-mediated suppression of insulin signaling in HFD-fed male mice. Hepatic BACH1 knockdown ameliorates hyperglycemia and improves insulin sensitivity in diabetic male mice. These results demonstrate a critical function for hepatic BACH1 in the regulation of insulin signaling and glucose homeostasis.

BACH1 regulates the differentiation of vascular smooth muscle cells from human embryonic stem cells via CARM1-mediated methylation of H3R17.

The role of BACH1 in the process of vascular smooth muscle cell (VSMC) differentiation from human embryonic stem cells (hESCs) remains unknown. Here, we find that the loss of BACH1 in hESCs attenuates the expression of VSMC marker genes, whereas overexpression of BACH1 after mesoderm induction increases the expression of VSMC markers during in vitro hESC-VSMC differentiation. Mechanistically, BACH1 binds directly to coactivator-associated arginine methyltransferase 1 (CARM1) during in vitro hESC-VSMC differentiation, and this interaction is mediated by the BACH1 bZIP domain. BACH1 recruits CARM1 to VSMC marker gene promoters and promotes VSMC marker expression by increasing H3R17me2 modification, thus facilitating in vitro VSMC differentiation from hESCs after the mesoderm induction. The increased expression of VSMC marker genes by BACH1 overexpression is partially abolished by inhibition of CARM1 or the H3R17me2 inhibitor TBBD in hESC-derived cells. These findings highlight the critical role of BACH1 in hESC differentiation into VSMCs by CARM1-mediated methylation of H3R17.

Cardiac-specific BACH1 ablation attenuates pathological cardiac hypertrophy by inhibiting the Ang II type 1 receptor expression and the Ca2+/CaMKII pathway.

AIMS: BACH1 is up-regulated in hypertrophic hearts, but its function in cardiac hypertrophy remains largely unknown. This research investigates the function and mechanisms of BACH1 in the regulation of cardiac hypertrophy. METHODS AND RESULTS: Male cardiac-specific BACH1 knockout mice or cardiac-specific BACH1 transgenic (BACH1-Tg) mice and their respective wild-type littermates developed cardiac hypertrophy induced by angiotensin II (Ang II) or transverse aortic constriction (TAC). Cardiac-specific BACH1 knockout in mice protected the hearts against Ang II- and TAC-induced cardiac hypertrophy and fibrosis, and preserved cardiac function. Conversely, cardiac-specific BACH1 overexpression markedly exaggerated cardiac hypertrophy and fibrosis and reduced cardiac function in mice with Ang II- and TAC-induced hypertrophy. Mechanistically, BACH1 silencing attenuated Ang II- and norepinephrine-stimulated calcium/calmodulin-dependent protein kinase II (CaMKII) signalling, the expression of hypertrophic genes, and hypertrophic growth of cardiomyocytes. Ang II stimulation promoted the nuclear localization of BACH1, facilitated the recruitment of BACH1 to the Ang II type 1 receptor (AT1R) gene promoter, and then increased the expression of AT1R. Inhibition of BACH1 attenuated Ang II-stimulated AT1R expression, cytosolic Ca2+ levels, and CaMKII activation in cardiomyocytes, whereas overexpression of BACH1 led to the opposite effects. The increased expression of hypertrophic genes induced by BACH1 overexpression upon Ang II stimulation was suppressed by CaMKII inhibitor KN93. The AT1R antagonist, losartan, significantly attenuated BACH1-mediated CaMKII activation and cardiomyocyte hypertrophy under Ang II stimulation in vitro. Similarly, Ang II-induced myocardial pathological hypertrophy, cardiac fibrosis, and dysfunction in BACH1-Tg mice were blunted by treatment with losartan. CONCLUSION: This study elucidates a novel important role of BACH1 in pathological cardiac hypertrophy by regulating the AT1R expression and the Ca2+/CaMKII pathway, and highlights potential therapeutic target in pathological cardiac hypertrophy.

BACH1 deficiency prevents neointima formation and maintains the differentiated phenotype of vascular smooth muscle cells by regulating chromatin accessibility.

The transcription factor BTB and CNC homology 1(BACH1) has been linked to coronary artery disease risk by human genome-wide association studies, but little is known about the role of BACH1 in vascular smooth muscle cell (VSMC) phenotype switching and neointima formation following vascular injury. Therefore, this study aims to explore the role of BACH1 in vascular remodeling and its underlying mechanisms. BACH1 was highly expressed in human atherosclerotic plaques and has high transcriptional factor activity in VSMCs of human atherosclerotic arteries. VSMC-specific loss of Bach1 in mice inhibited the transformation of VSMC from contractile to synthetic phenotype and VSMC proliferation and attenuated the neointimal hyperplasia induced by wire injury. Mechanistically, BACH1 suppressed chromatin accessibility at the promoters of VSMC marker genes via recruiting histone methyltransferase G9a and cofactor YAP and maintaining the H3K9me2 state, thereby repressing VSMC marker genes expression in human aortic smooth muscle cells (HASMCs). BACH1-induced repression of VSMC marker genes was abolished by the silencing of G9a or YAP. Thus, these findings demonstrate a crucial regulatory role of BACH1 in VSMC phenotypic transition and vascular homeostasis and shed light on potential future protective vascular disease intervention via manipulation of BACH1.

Head-to-Head Comparison of the Expression Differences of NECTIN-4, TROP-2, and HER2 in Urothelial Carcinoma and Its Histologic Variants.

Background: Antibody-drug conjugates (ADC), such as enfortumab vedotin (EV), sacituzumab govitecan (SG), and RC-48, have shown outstanding response rates to local advanced or metastatic urothelial carcinoma (UC). However, their corresponding target expression characteristics in UC and its histologic variants were unknown. Methods: We detected the expression of NECTIN-4, TROP-2, and HER2, which are the corresponding targets of ADCs EV, SG, and RC-48 in muscle-invasive UC through immunohistochemistry. Results: 161 consecutive samples from 2017 to 2021 of muscle-invasive UC and its histologic variants were obtained in Peking University First Hospital. Variant histology types included 72UC, 10 squamous carcinomas, 23 glandular carcinomas, 19 small cell carcinomas, 19 micropapillary variants, and 18 nested variants. NECTIN-4 expression was found to be 57/72 (79.2%), 10/10 (100%), 15/23 (65.2%), 4/19 (21.1%), 15/19 (78.9%), and 16/18 (88.9%) in conventional UC, squamous carcinoma, glandular carcinoma, small cell carcinoma, micropapillary, and nested variant, respectively, compared with 65/72 (90.3%), 8/10 (80.0%), 13/23 (56.5%), 3/19 (15.8%), 16/19 (84.2%), and 15/18 (83.3%) of TROP-2, and 26/72 (36.1%), 0, 5/23 (21.7%), 6/19 (31.6%), 5/19 (26.3%), and 7/18 (38.9%) of HER2.

Deletion of BACH1 Attenuates Atherosclerosis by Reducing Endothelial Inflammation.

BACKGROUND: The transcription factor BACH1 (BTB and CNC homology 1) suppressed endothelial cells (ECs) proliferation and migration and impaired angiogenesis in the ischemic hindlimbs of adult mice. However, the role and underlying mechanisms of BACH1 in atherosclerosis remain unclear. METHODS: Mouse models of atherosclerosis in endothelial cell (EC)-specific-Bach1 knockout mice were used to study the role of BACH1 in the regulation of atherogenesis and the underlying mechanisms. RESULTS: Genetic analyses revealed that coronary artery disease-associated risk variant rs2832227 was associated with BACH1 gene expression in carotid plaques from patients. BACH1 was upregulated in ECs of human and mouse atherosclerotic plaques. Endothelial Bach1 deficiency decreased turbulent blood flow- or western diet-induced atherosclerotic lesions, macrophage content in plaques, expression of endothelial adhesion molecules (ICAM1 [intercellular cell adhesion molecule-1] and VCAM1 [vascular cell adhesion molecule-1]), and reduced plasma TNF-α (tumor necrosis factor-α) and IL-1ß levels in atherosclerotic mice. BACH1 deletion or knockdown inhibited monocyte-endothelial adhesion and reduced oscillatory shear stress or TNF-α-mediated induction of endothelial adhesion molecules and/or proinflammatory cytokines in mouse ECs, human umbilical vein ECs, and human aortic ECs. Mechanistic studies showed that upon oscillatory shear stress or TNF-α stimulation, BACH1 and YAP (yes-associated protein) were induced and translocated into the nucleus in ECs. BACH1 upregulated YAP expression by binding to the YAP promoter. BACH1 formed a complex with YAP inducing the transcription of adhesion molecules. YAP overexpression in ECs counteracted the antiatherosclerotic effect mediated by Bach1-deletion in mice. Rosuvastatin inhibited BACH1 expression by upregulating microRNA let-7a in ECs, and decreased Bach1 expression in the vascular endothelium of hyperlipidemic mice. BACH1 was colocalized with YAP, and the expression of BACH1 was positively correlated with YAP and proinflammatory genes, as well as adhesion molecules in human atherosclerotic plaques. CONCLUSIONS: These data identify BACH1 as a mechanosensor of hemodynamic stress and reveal that the BACH1-YAP transcriptional network is essential to vascular inflammation and atherogenesis. BACH1 shows potential as a novel therapeutic target in atherosclerosis.

Carbonic anhydrase 10 functions as a tumor suppressor in renal cell carcinoma and its methylation is a risk factor for survival outcome.

Carbonic anhydrase 10 (CA10), one of the carbonic anhydrase isozymes, is explored to be downregulated in several tumor types, which indicates its critical role in tumorigenesis. However, its biologic and pathological function remains elusive in the pathogenesis of renal cell carcinoma (RCC). We examined expressions and functions of CA10 in RCC primary tumors and cell lines, assessed its tumor suppressive functions and further explored its impact on survival outcome of RCC patients. We found that CA10 was down-expressed in RCC primary tumors compared with adjacent non-malignant renal tissues. Promoter CpG methylation seemed to directly suppress the transcription of CA10 in RCC cells, which could be reversed by demethylation treatment. Restoration of CA10 in 786-O and Caki-2 cell lines inhibited their cell proliferation and promoted their apoptosis by regulating relevant apoptosis factors. Kaplan-Meier curve identified that CA10 methylation status was associated with progression-free survival in RCC (P = 0.021). Multivariate Cox regression analyses indicated the CA10 methylation status [HR, 4.724; 95% CI, 1.056-21.136; P = 0.042] was an independent predictor of disease progression. Collectively, our study demonstrates that CA10 as a tumor suppressor is frequently inactivated by promoter CpG methylation in RCC and its methylation is a risk factor for the prognosis of RCC.

Identifying Hypoxia Characteristics to Stratify Prognosis and Assess the Tumor Immune Microenvironment in Renal Cell Carcinoma.

Background: Renal cell carcinoma (RCC) is a common malignant tumor worldwide, and immune checkpoint inhibitors are a new therapeutic option for metastatic RCC. Infiltrating immune cells in the tumor microenvironment (TME) play a critical part in RCC biology, which is important for tumor therapy and prediction. Hypoxia is a common condition that occurs in the TME and may lead to RCC immunosuppression and immune escape. This study was conducted to analyze the extent of the hypoxia immune microenvironment in the TME of RCC and develop a hypoxia-related risk model for predicting the prognosis of patients with RCC. Methods: The gene expression profiles of 526 patients with RCC were downloaded from The Cancer Genome Atlas database. Combined with the hallmark-hypoxia gene dataset downloaded from Gene Set Enrichment Analysis, prognosis-related hypoxia genes were selected by survival analysis. A protein-protein interaction network and functional enrichment analysis were performed. A hypoxia-related risk model predicting the prognosis of patients with RCC was established using the least absolute shrinkage and selection operator. Data of 91 cases downloaded from the International Cancer Genome Consortium (ICGC) database were used for validation. CIBERSORT was applied to analyze the fractions of 22 immune cell types in the TME of RCC between low- and high-risk groups. The expression profiles of immunomodulators and immunosuppressive cytokines were also analyzed. Results: Ninety-three genes were significantly associated with poor overall survival of patients with RCC and were mainly involved in 10 pathways. Using the established hypoxia-related risk model, the receiver operating characteristic curves showed an accuracy of 76.1% (95% CI: 0.719-0.804), and Cox proportional hazards regression analysis revealed that the model was an independent predictor of the prognosis of patients with RCC [hazard ratio (HR) = 2.884; 95% CI: 2.090-3.979] (p < 0.001). Using the ICGC database, we verified that the low-risk score group had a better overall survival outcome than the high-risk group. Additionally, dividing the hypoxia risk score into high-risk and low-risk groups could predict the immune microenvironment of RCC. Conclusions: We demonstrated that a hypoxia-related risk model can be used to predict the outcomes of patients with RCC and reflect the immune microenvironment of RCC, which may help improve the overall clinical response to immune checkpoint inhibitors.

Renal Ewing's sarcoma/primitive neuroectodermal tumor (PNET): a case series of 7 patients and literature review.

BACKGROUND: Primitive neuroectodermal tumor (PNET) is a rare kind of sarcoma that is primarily found in the kidney and has a very poor prognosis. Here, we review and summarize the clinical data of patients with renal PNET in our center and follow up the patients for survival status. Although the current literature suggests that chemotherapy may benefit the survival of these patients, the information from our center suggests that this may not be the case. METHODS: We retrospectively analyzed the clinical data of patients with renal PNET diagnosed pathologically at Peking University First Hospital from January 1, 2007, to January 1, 2018. All of the patients were followed up for survival status. RESULTS: Seven patients with renal PNET were found. The ratio of males to females was 6:1. The median age was 29 years (21-72 years) at the time of diagnosis. The preoperative imaging examination showed a large renal mass protruding outwards from the renal contour, with internal necrosis and hemorrhage. Six/7 patients were diagnosed with distant metastasis or retroperitoneal lymph node metastasis. The main clinical manifestations of patients were pain (5/7) and fever (3/7). In immunohistochemistry, all patients' samples were CD99 positive. All patients died in our follow-up, with an average overall survival (OS) of 12.09 months (1.90-26.77 months). CONCLUSIONS: As a rare renal tumor, renal PNET has a propensity to occur in young males. Most patients have distant metastasis when they are diagnosed, and the prognosis is very poor. Effective treatments are urgently needed.

Identifying a hypoxia related score to predict the prognosis of bladder cancer: a study with The Cancer Genome Atlas (TCGA) database.

BACKGROUND: Recurrence is common in bladder cancer, with a hypoxic tumor microenvironment (TME) playing a role in genetic instability and prognosis of bladder cancer. However, we still lack practical hypoxia related model for predicting the prognosis of bladder cancer. In this study, we identified new prognosis-related hypoxia genes and established a new hypoxia score related signature. METHODS: The Gene Set Variation Analysis (GSVA) algorithm was utilized to calculate the hypoxia score of bladder cancer cases found on the The Cancer Genome Atlas (TCGA) database on the gene expression profiles. The cases were first divided into low- and high-hypoxia score groups and then differentially expressed genes (DEGs) expression analysis was conducted. Hypoxia-related genes were identified using weighted gene co-expression network analysis (WGCNA). We then conducted a protein-protein interaction (PPI) network and carried out functional enrichment analysis of the genes that overlapped between DEGs and hypoxia-related genes. LASSO Cox regression analysis was used to establish a hypoxia-related prognostic signature, which was validated using the GSE69795 dataset downloaded from GEO database. RESULTS: Results from Kaplan-Meier analysis showed that patients with a high hypoxia score had significantly poor overall survival compared to patients with low hypoxia score. We selected 270 DEGs between low- and high-hypoxia score groups, while WGCNA analysis identified 1,313 genes as hypoxia-related genes. A total of 170 genes overlapped between DEGs and hypoxia-related genes. LASSO algorithms identified 29 genes associated with bladder cancer prognosis, which were used to construct a novel 29-gene signature model. The prognostic risk model performed well, since the receiver operating characteristic (ROC) curve showed an accuracy of 0.802 (95% CI: 0.759-0.844), and Cox proportional hazards regression analysis proved the model an independent predictor with hazard ratio (HR) =1.789 (95% CI: 1.585-2.019) (P<0.001). The low-risk score patients had remarkably longer overall survival than patients with a higher score (survival rate 71.06% vs. 23.66%) in the The Cancer Genome Atlas (TCGA) cohort (P<0.0001) and in the dataset GSE69795 (P=0.0079). CONCLUSIONS: We established a novel 29-gene hypoxia-related signature model to predict the prognosis of bladder cancer cases. This model and identified hypoxia-related genes may further been used as biomarkers, assisting the evaluation of prognosis of bladder cancer cases and decision making in clinical practice.

m6A-mRNA Methylation Regulates Gene Expression and Programmable m6A Modification of Cellular RNAs With CRISPR-Cas13b in Renal Cell Carcinoma.

Background: N6-methyladenosine (m6A) is the most extensive messenger RNA modification. Despite recent advances in the biological roles of m6A, its role in the development and progression of renal cell carcinoma (RCC) remains unclear. Methods: In this study, we gained the transcriptome-wide m6A profile and gene expression pattern in RCC and paired adjacent peritumoral tissues by meRIP-seq and RNA-seq. m6A modifications of mRNAs were validated by meRIP-qPCR in tissues, and targeted methylation or demethylation was validated by using a CRISPR-Cas13b-based tool in RCC cell lines. Results: Our findings showed that there were 13,805 m6A peaks among 5,568 coding gene transcripts (mRNAs) in adjacent tissues and 24,730 m6A peaks among 6,866 mRNAs in tumor tissues. Furthermore, m6A modification sites were usually located in the coding sequences (CDS), and some near the start and stop codons. Gene Ontology analysis revealed that coding genes had differential N6-methyladenosine sites and were enriched in kidney development and cancer-related signaling pathways. We also found that different levels of m6A modifications could regulate gene expression. Conclusion: In summary, our results provided evidence for studying the potential function of RNA m6A modification and m6A-mediated gene expression regulation in human RCC.

Single-cell RNA analysis on ACE2 expression provides insights into SARS-CoV-2 potential entry into the bloodstream and heart injury.

Coronavirus disease-2019 (COVID-19) is a global pandemic with high infectivity and pathogenicity, accounting for tens of thousands of deaths worldwide. Recent studies have found that the pathogen of COVID-19, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), shares the same cell receptor angiotensin converting enzyme II (ACE2) as SARS-CoV. The pathological investigation of COVID-19 deaths showed that the lungs had characteristics of pulmonary fibrosis. However, how SARS-CoV-2 spreads from the lungs to other organs has not yet been determined. Here, we performed an unbiased evaluation of cell-type-specific expression of ACE2 in healthy and fibrotic lungs, as well as in normal and failed adult human hearts, using published single-cell RNA-seq data. We found that ACE2 expression in fibrotic lungs mainly locates in arterial vascular cells, which might provide a route for bloodstream spreading of SARS-CoV-2. Failed human hearts have a higher percentage of ACE2-expressing cardiomyocytes, and SARS-CoV-2 might attack cardiomyocytes through the bloodstream in patients with heart failure. Moreover, ACE2 was highly expressed in cells infected by respiratory syncytial virus or Middle East respiratory syndrome coronavirus and in mice treated by lipopolysaccharide. Our findings indicate that patients with pulmonary fibrosis, heart failure, and virus infection have a higher risk and are more susceptible to SARS-CoV-2 infection. The SARS-CoV-2 might attack other organs by getting into the bloodstream. This study provides new insights into SARS-CoV-2 blood entry and heart injury and might propose a therapeutic strategy to prevent patients from developing severe complications.

Bach1-induced suppression of angiogenesis is dependent on the BTB domain.

The transcription factor Bach1 impairs angiogenesis after ischemic injury by suppressing Wnt/ß-catenin signaling; however, the specific domains responsible for the anti-angiogenic effects of Bach1 remain unclear. This study determined the role of the BTB domain of Bach1 in ischemic angiogenesis. Bach1 is highly expressed in circulating endothelial cells from acute myocardial infarction patients and is the early induction gene after ischemia. Mice were treated with adenoviruses coding for GFP (AdGFP), Bach1 (AdBach1), or a Bach1 mutant lacking the BTB domain (AdBach1-ΔBTB) after surgically induced hind-limb ischemia. Measures of blood-flow recovery, capillary density, and the expression of vascular endothelial growth factor (VEGF) and heme oxygenase-1 (HO-1) were significantly lower and ROS levels were higher in the AdBach1 group, but not in AdBach1-ΔBTB animals. Furthermore, transfection with AdBach1, but not AdBach1-ΔBTB, in human endothelial cells was associated with significant declines in 1) capillary density and hemoglobin content in the Matrigel-plug assay, 2) proliferation, migration, tube formation, and VEGF and HO-1 expression in endothelial cells. Bach1 binds directly with TCF4, and this interaction is mediated by residues 81-89 of the Bach1 BTB domain and the N-terminal domain of TCF4. Bach1, but not Bach1-ΔBTB, also co-precipitated with histone deacetylase 1 (HDAC1), while the full-length HDAC1 proteins, but not HDAC1 mutants lacking the protein-interaction domain, co-precipitated with Bach1. Collectively, these results demonstrate that the anti-angiogenic activity of Bach1 is crucially dependent on molecular interactions that are mediated by the protein's BTB domain, and this domain could be a drug target for angiogenic therapy.

Epigenetic Alterations in Renal Cell Cancer With TKIs Resistance: From Mechanisms to Clinical Applications.

The appearance of tyrosine kinase inhibitors (TKIs) has been a major breakthrough in renal cell carcinoma (RCC) therapy. Unfortunately, a portion of patients with TKIs resistance experience disease progression after TKIs therapy. Epigenetic alterations play an important role in the development of TKIs resistance. Current evidence suggests that epigenetic alterations occur frequently in RCC patients with poor response to TKIs therapy, and modulation of them could enhance the cytotoxic effect of antitumor therapy. In this review, we summarize the currently known epigenetic alterations relating to TKIs resistance in RCC, focusing on DNA methylation, non-coding RNAs (ncRNAs), histone modifications, and their interactions with TKIs treatment. In addition, we discuss application of epigenetic alteration analyses in the clinical setting to predict prognosis of patients with TKIs treatment, and the potential use of epigenetics-based therapies to surmount TKIs resistance.

Bach1 regulates self-renewal and impedes mesendodermal differentiation of human embryonic stem cells.

The transcription factor BTB and CNC homology 1 (Bach1) is expressed in the embryos of mice, but whether Bach1 regulates the self-renewal and early differentiation of human embryonic stem cells (hESCs) is unknown. We report that the deubiquitinase ubiquitin-specific processing protease 7 (Usp7) is a direct target of Bach1, that Bach1 interacts with Nanog, Sox2, and Oct4, and that Bach1 facilitates their deubiquitination and stabilization via the recruitment of Usp7, thereby maintaining stem cell identity and self-renewal. Bach1 also interacts with polycomb repressive complex 2 (PRC2) and represses mesendodermal gene expression by recruiting PRC2 to the genes' promoters. The loss of Bach1 in hESCs promotes differentiation toward the mesendodermal germ layers by reducing the occupancy of EZH2 and H3K27me3 in mesendodermal gene promoters and by activating the Wnt/ß-catenin and Nodal/Smad2/3 signaling pathways. Our study shows that Bach1 is a key determinant of pluripotency, self-renewal, and lineage specification in hESCs.

Bach1: Function, Regulation, and Involvement in Disease.

The transcription factor BTB and CNC homology 1 (Bach1) is widely expressed in most mammalian tissues and functions primarily as a transcriptional suppressor by heterodimerizing with small Maf proteins and binding to Maf recognition elements in the promoters of targeted genes. It has a key regulatory role in the production of reactive oxygen species, cell cycle, heme homeostasis, hematopoiesis, and immunity and has been shown to suppress ischemic angiogenesis and promote breast cancer metastasis. This review summarizes how Bach1 controls these and other cellular and physiological and pathological processes. Bach1 expression and function differ between different cell types. Thus, therapies designed to manipulate Bach1 expression will need to be tightly controlled and tailored for each specific disease state or cell type.

Analysis of COMT Val158Met polymorphisms and methylation in Chinese male schizophrenia patients with homicidal behavior.

Schizophrenia is a severe mental disorder, and its mechanisms have not been fully elucidated. A functional single nucleotide polymorphism (SNP) present in the catechol-O-methyltransferase (COMT) gene, Val158Met (rs4680) (Chr22: 19,963,498), is possibly related to the violent behavior of schizophrenia patients. However, the specific variant that causes violent behavior is still unknown. Since the Val variation of Val158Met (rs4680) introduces a CG site into the sequence, the methylation level of the Val158Met (rs4680) region may also have an association with the homicidal behavior of schizophrenia patients. A case-control study was conducted that included 100 normal males, 100 schizophrenia inpatients, and 100 schizophrenia inpatients with homicidal behavior. A polymorphism of Val158Met (rs4680) and the methylation levels were analyzed by pyrosequencing. Compared to Met carriers, the Val/Val genotype was significantly associated with the homicidal behavior of schizophrenia patients. In addition, the methylation levels of the Val158Met (rs4680) region were significantly different between the three groups. Moreover, the methylation level of an rs4680-related CpG site was significantly associated with the Val/Val genotype which may contribute to the homicidal behavior of schizophrenia patients. In this study, we showed that the Val allele at Val158Met (rs4680) may be associated with the homicidal behavior of schizophrenia patients as well as that the methylation level of Val158Met (rs4680) could be affected by the variation of Val158Met (rs4680) and eventually contribute to the violent behavior of schizophrenia patients.