METTL3/YTHDF1 m6A axis promotes tumorigenesis by enhancing DDR2 expression in ovarian cancer

Ovarian cancer has the highest mortality among all gynecological malignancies. Therefore, it is urgent to determine the molecular mechanism of ovarian cancer progression. As the most prevalent modification of messenger RNA (mRNA), N6-Methyladenosine (m6A) modification is recognized as a key regulatory role in the progression of various tumors. However, the specific role of m6A and its related regulatory pathways in ovarian cancer (OV) remains unclear. In this study, we demonstrated that the METTL3/YTHDF1 m6A axis plays an important role in the progression of ovarian cancer. Depletion of METTL3/YTHDF1 impaired cancer proliferation and metastasis in vitro and in vivo. Mechanistically, The METTL3/YTHDF1 m6A axis directly binds to the mRNA of DDR2, thereby promoting the expression levels of the tumor promoter DDR2 and thus contributing to the progression of ovarian cancer. Collectively, our findings on the METTL3/YTHDF1/DDR2 m6A axis provide the insight into the underlying mechanism of ovarian carcinogenesis and highlight potential therapeutic targets for cancer treatment.

Identifying canonical and replicable multi-scale intrinsic connectivity networks in 100k+ resting-state fMRI datasets

Despite the known benefits of data-driven approaches, the lack of approaches for identifying functional neuroimaging patterns that capture both individual variations and inter-subject correspondence limits the clinical utility of rsfMRI and its application to single-subject analyses. Here, using rsfMRI data from over 100k individuals across private and public datasets, we identify replicable multi-spatial-scale canonical intrinsic connectivity network (ICN) templates via the use of multi-model-order independent component analysis (ICA). We also study the feasibility of estimating subject-specific ICNs via spatially constrained ICA. The results show that the subject-level ICN estimations vary as a function of the ICN itself, the data length, and the spatial resolution. In general, large-scale ICNs require less data to achieve specific levels of (within- and between-subject) spatial similarity with their templates. Importantly, increasing data length can reduce an ICN's subject-level specificity, suggesting longer scans may not always be desirable. We also find a positive linear relationship between data length and spatial smoothness (possibly due to averaging over intrinsic dynamics), suggesting studies examining optimized data length should consider spatial smoothness. Finally, consistency in spatial similarity between ICNs estimated using the full data and subsets across different data lengths suggests lower within-subject spatial similarity in shorter data is not wholly defined by lower reliability in ICN estimates, but may be an indication of meaningful brain dynamics which average out as data length increases.

hERG1 is involved in the pathophysiological process and inhibited by berberine in SKOV3 cells

The human ether-a-go-go-related potassium channel 1 (hERG1) is a functional component of the voltage-gated Kv11.1 potassium channel, which is commonly described as a crucial factor in the tumorigenesis of a variety of tumors. Ovarian cancer is one of the most severe types of cancer, with an extremely poor prognosis. Advances have been made in recent years; however, drug resistance and tumor recurrence remain critical issues underlying satisfactory treatment outcomes. Therefore, more effective antitumor agents with low levels of drug resistance for ovarian cancer treatment are urgently required in clinical practice. In the present study, hERG1 mRNA expression in ovarian tumor tissues and cell lines were measured by reverse transcription-quantitative polymerase chain reaction. Immunohistochemistry and western blotting were used to assess the expression levels of hERG1 protein. Cell proliferation, migration and invasion were assessed by Cell Counting Kit-8 assay and Transwell assay. A tumor xenograft assay was used to determine the growth of tumors in vivo. It was demonstrated that the expression levels of hERG1 were significantly elevated in ovarian cancer tissues and expressed in ovarian cancer cell lines, particularly in SKOV3 cells. Abnormal hERG1 expression was significantly associated with the proliferation, migration and invasion abilities of ovarian cancer. In addition, berberine (BBR) may be used as a potential drug in the treatment of ovarian cancer, possibly due to its inhibitory effects on the hERG1 channels. In conclusion, the present study demonstrated that hERG1 may be a potential therapeutic target in the treatment of ovarian cancer and provided novel insights into the mechanism underlying the antitumor effects of BBR in ovarian cancer.

miR-493 inhibits proliferation and invasion in pancreatic cancer cells and inversely regulated hERG1 expression

The human ether-a-go-go-related potassium channel 1 (hERG1) is a component of the voltage-gated Kv11.1 potassium channel, which has been recently indicated to have a crucial role in the tumorigenesis of multiple tumors, including pancreatic carcinoma. Pancreatic carcinoma is one of the most malignant human cancer types, which has an extremely poor prognosis. The present study demonstrated that the expression levels of hERG1 were markedly elevated in pancreatic cancer tissues and pancreatic cancer cell lines, and that the abnormal hERG1 expression was significantly associated with the proliferation and invasion ability of pancreatic cancer. Furthermore, hERG1 was identified to be a direct target of miR-493, which is generally reduced in pancreatic cancer tissues and cell lines. These findings provide a novel insight into the regulatory mechanism of miR-493/hERG1 in pancreatic cancer cell proliferation and invasion, which may aid the development of novel diagnostic and therapeutic strategies for pancreatic cancer in the future.

Helicobacter pylori infection is associated with an altered gastric microbiota in children

The intestinal microbiome in early life influences development of the mucosal immune system and predisposition to certain diseases. Because less is known about the microbiome in the stomach and its relationship to disease, we characterized the microbiota in the stomachs of 86 children and adults and the impact of Helicobacter pylori infection on the bacterial communities. The overall composition of the gastric microbiota in children and adults without H. pylori infection was similar, with minor differences in only low abundance taxa. However, the gastric microbiota in H. pylori-infected children, but not infected adults, differed significantly in the proportions of multiple high abundance taxa compared with their non-infected peers. The stomachs of H. pylori-infected children also harbored more diverse microbiota, smaller abundance of Firmicutes, and larger abundance of non-Helicobacter Proteobacteria and several lower taxonomic groups than stomachs of H. pylori-infected adults. Children with restructured gastric microbiota had higher levels of FOXP3, IL10, and TGFβ expression, consistent with increased T-regulatory cell responses, compared with non-infected children and H. pylori-infected adults. The gastric commensal bacteria in children are altered during H. pylori infection in parallel with more tolerogenic gastric mucosae, potentially contributing to the reduced gastric disease characteristic of H. pylori-infected children.

CPT1A methylation is associated with plasma adiponectin

BACKGROUND AND AIMS

Adiponectin, an adipose-secreted protein that has been linked to insulin sensitivity, plasma lipids, and inflammatory patterns, is an established biomarker for metabolic health. Despite clinical relevance and high heritability, the determinants of plasma adiponectin levels remain poorly understood.

METHODS AND RESULTS

We conducted the first epigenome-wide cross-sectional study of adiponectin levels using methylation data on 368,051 cytosine-phosphate-guanine (CpG) sites in CD4+ T-cells from the Genetics of Lipid Lowering Drugs and Diet Network (GOLDN, n = 991). We fit linear mixed models, adjusting for age, sex, study site, T-cell purity, and family. We have identified a positive association (regression coefficient ± SE = 0.01 ± 0.001, P = 3.4 × 10^-13) between plasma adiponectin levels and methylation of a CpG site in CPT1A, a key player in fatty acid metabolism. The association was replicated (n = 474, P = 0.0009) in whole blood samples from the Amish participants of the Heredity and Phenotype Intervention (HAPI) Heart Study as well as White (n = 592, P = 0.0005) but not Black (n = 243, P = 0.18) participants of the Bogalusa Heart Study (BHS). The association remained significant upon adjusting for BMI and smoking in GOLDN and HAPI but not BHS. We also identified associations between methylation loci in RNF145 and UFM1 and plasma adiponectin in GOLDN and White BHS participants, although the association was not robust to adjustment for BMI or smoking.

CONCLUSION

We have identified and replicated associations between several biologically plausible loci and plasma adiponectin. These findings support the importance of epigenetic processes in metabolic traits, laying the groundwork for future translational applications.

Interactions between maternal killer cell immunoglobulin receptor genes and foetal HLA ligand genes contribute to type 1 diabetes susceptibility in Han Chinese

In this study, we aimed to test the hypothesis that KIR haplotypes (that interact with HLA class I molecules) are associated with susceptibility in patients with T1DM in utero through maternal-foetal interaction of KIR and their HLA class I ligands in Han Chinese population. We determined the KIR genes and KIR/ligand gene combination frequencies in 59 Han Chinese children with T1D and their mothers and compared it with 159 healthy control children and their mothers. The absence of KIR-2DS1 in the mother and the presence of HLA-C2 ligand in the child were negatively associated with type 1 diabetes in the child. Our results indicate that maternal KIR genes and their interaction with foetal HLA-C2 may contribute to the risk of type 1 diabetes among Han Chinese children.

Screening genes crucial for pediatric pilocytic astrocytoma using weighted gene coexpression network analysis combined with methylation data analysis

To identify novel genes associated with pediatric pilocytic astrocytoma (PA) for better understanding the molecular mechanism underlying the pediatric PA pathogenesis. Gene expression profile data of GSE50161 and GSE44971 and the methylation data of GSE44684 were downloaded from Gene Expression Omnibus. The differentially expressed genes (DEGs) between PA and normal control samples were screened using the limma package in R, and then used to construct weighted gene coexpression network (WGCN) using the WGCN analysis (WGCNA) package in R. Significant modules of DEGs were selected using the clustering analysis. Function enrichment analysis of the DEGs in significant modules were performed using the WGCNA package and clusterprofiler package in R. Correlation between methylation sites of DEGs and PA was analyzed using the CpGassoc package in R. Totally, 3479 DEGs were screened in PA samples. Thereinto, 3424 DEGs were used to construct the WGCN. Several significant modules of DEGs were selected based on the WGCN, in which the turquoise module was positively related to PA, whereas blue module was negatively related to PA. DEGs (for example, DOCK2 (dedicator of cytokinesis 2), DOCK8 and FCGR2A (Fc fragment of IgG, low affinity IIa)) in blue module were mainly involved in Fc gamma R-mediated phagocytosis pathway and natural killer cell-mediated cytotoxicity pathway. Methylations of 14 DEGs among the top 30 genes in blue module were related to PA. Our data suggest that DOCK2, DOCK8 and FCGR2A may represent potential therapeutic targets in PA that merits further investigation.

Berberine induces hERG channel deficiency through trafficking inhibition

AIMS

The human ether-a-go-go-related gene (hERG) encodes the α subunit of the IKr, which plays an essential role in repolarization of action potentials. hERG channels are targeted by various pro-arrhythmic drugs. Berberine (BBR) was previously found to acutely inhibit hERG currents and prolong action potential duration. The present study aimed to determine long-term effects of BBR on the expression of 135kDa/155kDa hERG and the mechanism.

METHODS AND RESULTS

hERG expression was assessed by western blot. Mature hERG (155 kDa) was reduced, whereas ER-located hERG (135 kDa) was increased by BBR. This indicated that hERG was restricted to the ER and that BBR disrupted channel trafficking. To determine the mechanism of trafficking inhibition, we performed western blot and immunoprecipitation to test folding of hERG by assessing interaction between hERG and Hsp90/Hsp70. Both the expression of Hsp90 and its interaction with hERG were strongly decreased by BBR. These data suggest that BBR reduces channel folding to induce trafficking inhibition. Western blot and confocal imaging were used to further detect whether the unfolded protein response (UPR) was activated. Active ATF6, a marker of the UPR, was activated by BBR. Calnexin and calreticulin, chaperones that are activated by ATF6 to assist channel folding, were also elevated and increasingly colocalized with hERG. These data also demonstrate that the UPR was activated. Immunoprecipitation and western blot assays were performed after BBR treatment to examine ubiquitination and degradation, common endpoints of the UPR. We found that the ER-restricted hERG was ubiquitinized and degraded in the lysosomes and proteasomes.

CONCLUSION

Our study demonstrates that BBR induces hERG channel deficiency by inhibiting channel trafficking after incubation for 24h. Trafficking inhibition activated the UPR, and the ER-restricted hERG was ubiquitinized and degraded in lysosomes and proteasomes.

Whole-exome sequencing and an iPSC-derived cardiomyocyte model provides a powerful platform for gene discovery in left ventricular hypertrophy

Rationale: Left ventricular hypertrophy (LVH) is a heritable predictor of cardiovascular disease, particularly in blacks. Objective: Determine the feasibility of combining evidence from two distinct but complementary experimental approaches to identify novel genetic predictors of increased LV mass. Methods: Whole-exome sequencing (WES) was conducted in seven African-American sibling trios ascertained on high average familial LV mass indexed to height (LVMHT) using Illumina HiSeq technology. Identified missense or nonsense (MS/NS) mutations were examined for association with LVMHT using linear mixed models adjusted for age, sex, body weight, and familial relationship. To functionally assess WES findings, human induced pluripotent stem cell-derived cardiomyocytes (induced pluripotent stem cell-CM) were stimulated to induce hypertrophy; mRNA sequencing (RNA-seq) was used to determine gene expression differences associated with hypertrophy onset. Statistically significant findings under both experimental approaches identified LVH candidate genes. Candidate genes were further prioritized by seven supportive criteria that included additional association tests (two criteria), regional linkage evidence in the larger HyperGEN cohort (one criterion), and publically available gene and variant based annotations (four criteria). Results: WES reads covered 91% of the target capture region (of size 37.2 MB) with an average coverage of 65×. WES identified 31,426 MS/NS mutations among the 21 individuals. A total of 295 MS/NS variants in 265 genes were associated with LVMHT with q-value <0.25. Of the 265 WES genes, 44 were differentially expressed (P < 0.05) in hypertrophied cells. Among the 44 candidate genes identified, 5, including HLA-B, HTT, MTSS1, SLC5A12, and THBS1, met 3 of 7 supporting criteria. THBS1 encodes an adhesive glycoprotein that promotes matrix preservation in pressure-overload LVH. THBS1 gene expression was 34% higher in hypertrophied cells (P = 0.0003) and a predicted conserved and damaging NS variant in exon 13 (A2099G) was significantly associated with LVHMT (P = 4 × 10⁻⁶). Conclusion: Combining evidence from cutting-edge genetic and cellular experiments can enable identification of novel LVH risk loci.

Inhibiting effect of moderate hypothermia on cell apoptosis after diffuse brain injury in rats

OBJECTIVE

To explore the variant processes of cell apoptosis and the inhibiting effect of moderate hypothermia on cell apoptosis after diffuse brain injury.

METHODS

Models of diffuse brain injury were induced by the trauma device reported by Marmarou. A total of 128 Wistar rats were divided into 4 groups: the uninjured group (Group A, n=8), the severely injured group (Group B, n=60), the mildly injured group (Group C, n=30) and the mild hypothermia group (Group D, n=30). In Group D, the severely injured rats were treated with moderate hypothermia to keep the rectal temperature at 32 degrees C (standard deviation for 0.1 degree C) for 6 hours. Then the morphology, the characteristics and the quantity of apoptotic cells in the cerebral cortex and in the hippocampus regions after different severities of craniocerebral injuries were observed and compared under an electronic microscope, with terminal deoxynucleotidyl nick end labeling (TUNEL) in DNA fragmentation and with agarose gel electrophoresis.

RESULTS

TUNEL showed apoptotic cells increased according to the injury severity, and they peaked at 48 hours after injury and then declined. In Group C, apoptosis was located in the CA(2) and CA(3) areas of the hippocampus. And in Group B, apoptosis increased evidently, and located in the whole hippocampus and in the frontal and parietal cortex regions. The hypothermia-treated rats had some apoptotic cells, too. However, even at 24, 48 and 72 hours after injury there were significantly fewer apoptotic cells in the cortex and in the hippocampus in Group D than that in the non-treated groups. Electron microscopy showed that the apoptotic cells were round and shrunken in morphology and the nuclei were round and condensed at 24 and 48 hours after injury. And the apoptosis at 48 hours was more severe than that at 24 hours. The hypothermia-treated rats had no apoptotic cells. Gel electrophoresis showed that characteristic DNA "ladders" were observed in the cortex and in the hippocampus at 48 hours after severe injury. But there was no DNA "ladder" at other time points in the severely injured group, in the mildly injured group and in the hypothermia-treated group.

CONCLUSIONS

It suggests that apoptosis occurs after diffuse brain injury and apoptotic cells increase with the injury severity. Moderate hypothermia has a specific inhibiting effect on cell apoptosis after diffuse brain injury in rats.