An analysis of POMC gene methylation and expression in patients with schizophrenia.

Schizophrenia is a chronic mental disorder that affects millions of people and is believed to be caused by both environmental and genetic factors. Despite extensive research, the exact mechanisms underlying schizophrenia are still unclear. Studies have shown that numerous psychiatric disorders are associated with methylation of the POMC gene, which encodes adrenocorticotropic hormone, a critical player in the hypothalamic-pituitary-adrenal axis. However, the association between DNA methylation in POMC patients and schizophrenia remains unclear. In this study, we evaluated three fragments of the POMC promoter region, including 51 CpG sites, in the peripheral blood of schizophrenia patients and healthy controls. The POMC protein level was measured via enzyme-linked immunosorbent assay (ELISA). The schizophrenia group exhibited significantly greater levels of methylation of the POMC gene than those in the control group. The methylation level of the POMC-2 fragment was significantly greater in the patient group than in the control group. There were 17 significantly hypermethylated CpG sites in the patient group. After stratification by sex, POMC methylation levels were found to be significantly greater in male schizophrenia patients than in healthy controls; the methylation levels of POMC-2 fragments were greater in the male patient group; nine CpG sites were significantly hypermethylated in the male patient group; and only one CpG site was significantly hypermethylated in the female patient group. The POMC protein level in patients was significantly lower than that in healthy controls. These findings demonstrate that the DNA methylation of POMC might be associated with the pathophysiology of schizophrenia. Overall, studying the correlation between POMC methylation and schizophrenia may contribute to the diagnosis and evaluation of neuropsychiatric disorders.

Sex-dependent association of DNA methylation in the coding region of the corticotropin-releasing hormone gene and schizophrenia spectrum disorder.

BACKGROUND: Schizophrenia spectrum disorder (SSD) is a common mental disorder causing severe and chronic disability. Epigenetic changes in genes related to the hypothalamic-pituitary-adrenal (HPA) axis are believed to play an important role in SSD pathogenesis. The methylation status of the corticotropin-releasing hormone (CRH) gene, which is central to the HPA axis, has not been investigated in patients with SSD. AIM: We investigated the methylation status of the coding region of the CRH gene (hereafter, CRH methylation) using peripheral blood samples from patients with SSD. SUBJECTS AND METHODS: We used sodium bisulphite and MethylTarget to determine CRH methylation after collecting peripheral blood samples from 70 patients with SSD who had positive symptoms and 68 healthy controls. RESULTS: CRH methylation was significantly increased in patients with SSD, especially in male patients. CONCLUSIONS: Differences in CRH methylation were detectable in the peripheral blood of patients with SSD. Epigenetic abnormalities in the CRH gene were closely related to positive symptoms of SSD, suggesting that epigenetic processes may mediate the pathophysiology of SSD.

Genetic polymorphism investigation of 16 X-STR loci in the Bai ethnic minority in Yunnan Province, Southwest China.

To investigate the genetic variation and forensic efficiency of 16 X-chromosomal short tandem repeat (X-STR) loci (DX6795, DXS9902, DXS8378, HPRTB, GATA165B12, DXS7132, DXS7424, DXS6807, DXS6803, GATA172D05, DXS6800, DXS10134, GATA31E08, DXS10159, DXS6789, and DXS6810) in the Bai minority, we calculated allele frequencies, forensic parameters, and haplotype frequencies in 424 (202 males and 222 females) unrelated, healthy Bai individuals from Dali Bai Autonomous Prefecture in Yunnan Province, China. We observed a total of 132 alleles; 5-19 alleles were detected in each locus, and the corresponding allele frequencies ranged from 0.0016 to 0.7589. All of the loci detected were highly polymorphic in the Bai population in Yunnan Province, except DXS6800. The values for the combined power of discrimination in females (PDf) and males (PDm) were 0.999999999999996 and 0.999999997487061, respectively. According to a phylogenetic tree, neighboring populations and different nationalities in the same area appeared to have relatively close evolutionary relationships. This study provides and complements X-chromosome genetic polymorphism data for the Bai people in Yunnan Province, Southwest China, and enriches the available reference materials for this Chinese minority population.

Association of mineralocorticoid receptor gene (NR3C2) hypermethylation in adult males with aggressive behavior.

Aggressive behavior may have adaptive value under some environmental conditions. However, when it is extreme or improper, it may also lead to maladaptive results, seriously threatening human and social well-being. Aggressive behavior is a multifactorial disease, and the etiology is largely unknown. The stress-related hypothalamic-pituitary-adrenal (HPA) axis is a crucial system in the stress response that has emerged as a potential mechanism of aggressive behavior. The NR3C2 gene is an important regulator of the HPA axis: it is involved in regulating HPA axis activity and behavioral adaptation to stressors. Moreover, the epigenetic mechanism of DNA methylation has been suggested to mediate the development of aggressive behavior. However, the association between NR3C2 methylation and aggressive behavior has not been studied. In the present study, we assessed NR3C2 methylation (including three regions: promoter P1, exon 1α, and the sequence downstream of exon 1α) in peripheral blood DNA of adult males with aggressive behavior (n = 106) and healthy controls (n = 104). We found the NR3C2 gene to be associated with aggressive behavior, with hypermethylation detected in the entire aggressive behavior group as well as in the robbery subgroup compared to controls. In addition, analysis of methylation at 75 CpG sites revealed that some important CpG sites are associated with aggressive behavior. Our results suggest that HPA axis-related gene NR3C2 methylation is associated with aggressive behavior. These results lend support for using NR3C2 DNA methylation as a potential biomarker of aggressive behavior.

Glucocorticoid receptor gene (NR3C1) is hypermethylated in adult males with aggressive behaviour.

Aggressive behaviour is a serious threat to the personal safety and property of others due to the potential that the assailant may hurt people, himself/herself or objects, and aggression has always been one of the focuses of research and concern. Accumulating evidence suggests that the hypothalamic-pituitary-adrenal (HPA) axis plays a major role in the development, elicitation, enhancement and genetic susceptibility of aggressive behaviour in humans and animals. GR (NR3C1) plays a crucial role in controlling HPA activity, which directly affects aggressive behaviour. Here, we investigated the methylation state of the NR3C1 gene promoter region and its role in aggressive behaviour in adult males for the first time by applying a case-control approach (N = 106 controls, N = 104 patients). Methylation of NR3C1 was measured in peripheral blood samples at exons 1D, 1B and 1F via sodium bisulfite treatment combined with the MethylTarget method. Methylation of the NR3C1 gene was significantly correlated with aggressive behaviour, and the methylation levels of 1D, 1B and 1F were upregulated in the aggressive behaviour group, intentional injury subgroup and robbery subgroup, and the significance varied. In addition, multiple CpG sites were found to be significantly associated with aggressive behaviour. These results suggest that epigenetic aberrations of NR3C1 are associated with aggressive behaviour, and epigenetic processes might mediate aggressive behaviour by affecting the activity of the HPA axis. This correlative study between DNA methylation of the NR3C1 gene and aggressive behaviour in patients may be helpful for forensic assessments.

Retraction "Methylation of the MAOA promoter is associated with schizophrenia".

[This retracts the article DOI: 10.21037/atm-20-4481.].

Methylation of the MAOA promoter is associated with schizophrenia.

BACKGROUND: Earlier studies have shown that patients with schizophrenia have abnormalities in DNA methylation. Monoamine oxidase A (MAOA) has been extensively studied due to its biological role in neurological function. However, the relationship between the DNA methylation of the MAOA gene and schizophrenia is unclear. This study aims to elucidate the relationship between the methylation of the MAOA gene promoter and schizophrenia. METHODS: There were 151 individuals with schizophrenia (104 males and 47 females), which were diagnosed according to DSM-V, the DNA of peripheral blood of all samples was extracted and chemically modified with bisulfite. The promoter region of MAOA gene was sequenced by Methylation Target Technical Method (MethylTargetTM), and 247 controls (204 males and 43 females) included in the study. MAOA gene promoter methylation was compared between the case and control groups. Meanwhile, we measured DNA methylation in two regions of MAOA (MAOA-2 and MAOA-3). RESULTS: In the male schizophrenia group (BM) and the male control group (DM), MAOA-2 and MAOA-3 methylation were positively associated with schizophrenia. In the female schizophrenia group (BF) and the female control group (DF), MAOA-2 methylation was associated with schizophrenia. CONCLUSIONS: Although the role of gene methylation in the development of schizophrenia is still unclear, our findings suggest that DNA methylation of MAOA may contribute to the onset of schizophrenia.

Sex-dependent association of mineralocorticoid receptor gene (NR3C2) DNA methylation and schizophrenia.

Schizophrenia is a complex disease caused by genetic and environmental factors. Epigenetic regulation mediates gene-environment interactions by modulating gene expression. Abnormal activation of the hypothalamic-pituitary-adrenal (HPA) axis has been widely reported in schizophrenia patients. The DNA methylation levels of critical genes are associated with HPA axis activity, which is linked to schizophrenia pathogenesis. The mineralocorticoid receptor gene NR3C2 regulates HPA axis activity. However, how NR3C2 methylation affects the development of schizophrenia remains unknown. Here, we investigated the DNA methylation state of NR3C2, including the promoter P1 (NR3C2-1, NR3C2-2 and NR3C2-3) and exon 1α and its downstream sequence (NR3C2-4), in schizophrenia. Peripheral blood DNA from 80 schizophrenia patients and 128 healthy controls was used to assess NR3C2 DNA methylation via sodium bisulfite treatment and the MethylTarget method. NR3C2-4 region was hypermethylated in schizophrenia patients compared with healthy controls in the female group. Specific CpG sites in P1 and NR3C2-4 region were associated with schizophrenia, with sex-specific effects. These findings showed a relationship between NR3C2 DNA methylation and schizophrenia, revealing that epigenetic processes may mediate schizophrenia pathophysiology. Further research should address the potential epigenetic mechanisms of the relationship between NR3C2 and schizophrenia.

DNA Methylation Analysis of the NR3C1 Gene in Patients with Schizophrenia.

Schizophrenia is a heterogeneous mental disorder caused by genetic and environmental factors, and epigenetic mechanisms play a vital role in its pathogenesis. Evidence suggests that some psychiatric disorders are linked to methylation of the glucocorticoid receptor gene NR3C1, a key regulator of the hypothalamic-pituitary-adrenal (HPA) axis. However, the contribution of NR3C1 methylation to schizophrenia has not yet been investigated. By applying a case-control approach (N = 128 controls, N = 80 patients), we for the first time examined the methylation state of the NR3C1 gene promoter region and its role in schizophrenia. Using peripheral blood samples, NR3C1 methylation in exons 1D, 1B, 1F, and 1H was assessed via sodium bisulfite treatment combined with the MethylTarget method. NR3C1 methylation at exon 1B was positively associated with schizophrenia in females but not in males. Nonetheless, specific CpG sites in exon 1D, 1B, 1H, and 1F regions were found to be associated with schizophrenia, usually with sex specificity. These results suggest that epigenetic aberrations of NR3C1 are associated with the pathophysiology of schizophrenia, and epigenetic processes possibly mediate psychopathology through effects on HPA axis activity. Correlation analysis between NR3C1 gene methylation and schizophrenia may be helpful for the assessment of forensic psychiatry.

A genetic variant rs13293512 in the promoter of let-7 is associated with an increased risk of breast cancer in Chinese women.

Growing evidence has demonstrated that single-nucleotide polymorphisms (SNPs) in the promoter of miRNA may influence individuals' susceptibility to human diseases. We examined two SNPs rs10877887 and rs13293512 in the promoters of let-7 family to determine if the two SNPs were related to the occurrence of breast cancer (BC). Genotyping of the two SNPs was performed by PCR and restriction fragment length polymorphism analysis or TaqMan assay in 301 BC patients and 310 age matched controls. We found a higher frequency of rs13293512 CC genotype and rs13293512 C allele amongst BC patients (CC vs TT: adjusted odds ratio (OR) = 1.78; 95% CI: 1.14-2.80; P=0.012; C vs T: adjusted OR = 1.33; 95% CI: 1.06-1.67; P=0.013). Stratification analysis showed that rs13293512 CC genotype was associated with an increased risk of BC in patients with negative estrogen receptor (adjusted OR = 2.39; 95% CI: 1.32-4.30; P=0.004), patients with negative progesterone receptor (adjusted OR = 1.92; 95% CI: 1.11-3.33; P=0.02), patients with T1-2 stage cancer (adjusted OR = 1.77; 95% CI: 1.07-2.93; P=0.03), and patients with N1-3 stage cancer (adjusted OR = 1.89; 95% CI: 1.13-3.17; P=0.015). These findings suggest that rs13293512 in the promoter of let-7a-1/let-7f-1/let-7d cluster may be a possible biomarker for the development of BC in Chinese women.

Generation of biallelic knock-out sheep via gene-editing and somatic cell nuclear transfer.

Transgenic sheep can be used to achieve genetic improvements in breeds and as an important large-animal model for biomedical research. In this study, we generated a TALEN plasmid specific for ovine MSTN and transfected it into fetal fibroblast cells of STH sheep. MSTN biallelic-KO somatic cells were selected as nuclear donor cells for SCNT. In total, cloned embryos were transferred into 37 recipient gilts, 28 (75.7%) becoming pregnant and 15 delivering, resulting in 23 lambs, 12 of which were alive. Mutations in the lambs were verified via sequencing and T7EI assay, and the gene mutation site was consistent with that in the donor cells. Off-target analysis was performed, and no off-target mutations were detected. MSTN KO affected the mRNA expression of MSTN relative genes. The growth curve for the resulting sheep suggested that MSTN KO caused a remarkable increase in body weight compared with those of wild-type sheep. Histological analyses revealed that MSTN KO resulted in muscle fiber hypertrophy. These findings demonstrate the successful generation of MSTN biallelic-KO STH sheep via gene editing in somatic cells using TALEN technology and SCNT. These MSTN mutant sheep developed and grew normally, and exhibited increased body weight and muscle growth.

The prion protein gene polymorphisms associated with bovine spongiform encephalopathy susceptibility differ significantly between cattle and buffalo.

Prion protein, encoded by the prion protein gene (PRNP), plays a crucial role in the pathogenesis of transmissible spongiform encephalopathies (TSEs). Several polymorphisms within the PRNP are known to be associated with influencing bovine spongiform encephalopathy (BSE) susceptibility in cattle, namely two insertion/deletion (indel) polymorphisms (a 23-bp indel in the putative promoter and a 12-bp indel in intron 1), the number of octapeptide repeats (octarepeats) present in coding sequence (CDS) and amino acid polymorphisms. The domestic buffaloes, Bubalus bubalis, are a ruminant involved in various aspects of agriculture. It is of interest to ask whether the PRNP polymorphisms differ between cattle and buffalo. In this study, we analyzed the previously reported polymorphisms associated with BSE susceptibility in Chinese buffalo breeds, and compared these polymorphisms in cattle with BSE, healthy cattle and buffalo by pooling data from the literature. Our analysis revealed three significant findings in buffalo: 1) extraordinarily low deletion allele frequencies of the 23- and 12-bp indel polymorphisms; 2) significantly low allelic frequencies of six octarepeats in CDS and 3) the presence of S4R, A16V, P54S, G108S, V123M, S154N and F257L substitutions in buffalo CDSs. Sequence alignments comparing the buffalo coding sequence to other species were analyzed using the McDonald-Kreitman test to reveal five groups (Bison bonasus, Bos indicus, Bos gaurus, Boselaphus tragocamelus, Syncerus caffer caffer) with significantly divergent non-synonymous substitutions from buffalo, suggesting potential divergence of buffalo PRNP and others. To the best of our knowledge this is the first study of PRNP polymorphisms associated with BSE susceptibility in Chinese buffalo. Our findings have provided evidence that buffaloes have a unique genetic background in the PRNP gene in comparison with cattle.

Progress on low susceptibility mechanisms of transmissible spongiform encephalopathies.

Transmissible spongiform encephalopathies (TSEs), also known as prion diseases, are a group of fatal neurodegenerative diseases detected in a wide range of mammalian species. The "protein-only" hypothesis of TSE suggests that prions are transmissible particles devoid of nucleic acid and the primary pathogenic event is thought to be the conversion of cellular prion protein (PrP(C)) into the disease-associated isoform (PrP(Sc)). According to susceptibility to TSEs, animals can be classified into susceptible species and low susceptibility species. In this review we focus on several species with low susceptibility to TSEs: dogs, rabbits, horses and buffaloes. We summarize recent studies into the characteristics of low susceptibility regarding protein structure, and biochemical and genetic properties.