Small‐conductance Ca2+‐activated K+ channel subtype2 (SK2) are stable macromolecular complexes that regulate myocardial excitability and Ca2+ homeostasis. Junctophilin‐2 (JP2) is a membrane‐binding protein, which provides functional crosstalk by physically linking with the cell‐surface and intracellular ion channels. We previously demonstrated that the MORN domain of JP2 interacts with SK2 channels. However, the roles of the JP2 MORN domain in regulating the precise subcellular localization and molecular modulation of SK2 have not yet been incompletely understood. In the present study, in vitro and in vivo assays were used to confirm the physical interactions between the SK2 channel and JP2 in H9c2 and HEK293 cells, with a concentration on the association between the C‐terminus of SK2 channels and the MORN domain of JP2. Furthermore, the membrane expression of SK2 were found to be significantly impaired by the mutation or knockdown of JP2. Using immunofluorescence staining along with Golgi/early endosome markers, we studied the mechanisms of JP2‐regulated SK2 membrane trafficking, which indicates that the JP2 MORN domain is probably necessary for the retrograde trafficking of SK2 channels. The functional study demonstrates that whole cell SK2 current densities recorded from the HEK293 cells co‐expressing the JP2‐MORN domain with SK2 were significantly augmented, compared with cells expressing SK2 alone. Our findings suggest that the MORN domain of JP2 directly modulates SK2 channel current amplitude and trafficking, through its interaction with an overlapping region of the JP2 MORN domain on the SK2 C‐terminus.

Aim To analyze and compare the mRNA N6-methyladenosine modifications in transverse aortic constriction induced mice hearts and normal mice hearts. Materials and methods Colorimetric quantification was used to probe the changes in m6A modifications in the total RNA. The expression of m6A-related enzymes was analyzed via qRT-PCR and western blotting. RNA-seq and MeRIP-seq were performed to identify genes with differences in m6A modifications or expression in the transcriptome profile. Results Compared with the control group, the TAC group exhibited higher m6A methylation levels. FTO and WTAP were downregulated after TAC, while METTL3 was significantly downregulated at the protein level. MeRIP-seq revealed that 1179 m6A peaks were upmethylated and 733 m6A peaks were downmethylated, and biological analysis of these genes exhibited a strong relationship with heart function. Conclusion Our findings provide novel information regarding m6A modification and gene expression changes in cardiac hypertrophy, which may be fundamental for further research.

Background: Ryanodine receptor type 2 (RyR2) mediate Ca 2+ release from the endoplasmic and sarcoplasmic reticulum (ER and SR), which is involved in the peripheral coupling of mouse cardiomyocytes, and thereby plays an important role in cardiac contraction. Junctophilin-2 (JPH2, JP2) is anchored to the plasma membrane (PM) and membranes of the ER and SR, and modulates intracellular Ca 2+ handling through regulation of RyR2. However, the potential RyR2 binding region of JPH2 is poorly understood. Methods: The interaction of JPH2 with RyR2 was studied using LC-MS/MS , bioinformatic analysis,co-immunoprecipitation studies in cardiac SR vesicles. GST-pull down analysis was performed to investigate the physical interaction between RyR2 and JPH2 fragments. Immunofluorescent staining was carried out to determine the colocalization of RyR2 and JPH2 in isolated mouse cardiomyocytes. Ion Optix photometry system was used to measure the levels of intracellular Ca 2+ transients in cardiomyocytes isolated from JPH2 knock down mice. Results: We report that (i) JPH2 interacts with RyR2 and (ii) the C terminus of the JPH2 protein can pull down RyR2 receptors. Confocal immunofluorescence imaging indicated that the majority of JPH2 and RyR2 proteins were colocalized near Z-lines. A decrease in the levels of JPH2 expression reduced the amplitude of Ca 2+ transients in cardiomyocytes. Conclusions: This study suggests that the C terminus domain of JPH2 is required for interactions with RyR2 in the context of peripheral coupling of mouse cardiomyocytes, which provide a molecular mechanism for looking for Ca 2+ - related diseases prevention strategies.

Curcumin shows an anti‐cancer role in many kinds of tumors. However, the mechanism of its anti‐tumor function in esophageal squamous cell carcinoma (ESCC) remains largely unknown. Herein, we explored the therapeutic potential of curcumin for esophageal cancer. Curcumin could time‐ and dose‐dependently inhibit ESCC cells activity. Additionally, ESCC cells exposed to 20 μM of curcumin exhibited significantly decreased proliferative and invasive capacities, as well as enhanced cell apoptosis. ESCC tissues and cells exhibited significantly increased circNRIP1 expression when compared to their counterparts. circNRIP1 knockdown markedly impaired cell proliferation, clone formation, cell migration and invasion but promoted apoptosis. Exposure to 10–20 μM of curcumin inhibited circNRIP1 expression, however, overexpression of circNRIP1 could significantly restored the biological characteristics that were inhibited by curcumin exposure in vivo and in vitro. circNRIP1 promoted the malignancy of ESCC by combining miR‐532‐3p, and downstream AKT3. Curcumin inhibited AKT phosphorylation by up‐regulating miR‐532‐3p expression, thereby inhibiting the activation of the AKT pathway. In summary, curcumin is a potent inhibitor of ESCC growth, which can be achieved through the regulation of the circNRIP1/miR‐532‐3p/AKT pathway. This research may provide new mechanisms for curcumin to inhibit the malignant development of ESCC.

number and podocyte number play pivotal roles in the development of CKD we utilised a mouse model of low birth weight and low nephron number to investigate podocyte number in the early postnatal period and whether podocyte number is associated with increased risk of renal pathophysiology in adulthood. Methods: C57Bl6 female mice were exposed to a maternal low (LPD; 8%) or normal (NPD; 20%) protein diet for 3 weeks prior to pregnancy, throughout pregnancy and up until weaning (PN21), when the kidneys of one male and one female per litter were collected for analysis of nephron number, podocyte endowment, glomerular volume and podocyte density. A 'second-hit' was induced in remaining littermates at 6 weeks of age by administration of streptozotocin (STZ, 55mg/kg 5x daily doses; sodium citrate for control) to induce moderate to severe diabetes. These offspring were followed for a further 18 weeks with hyperglycaemia and urinary albumin/creatinine ratio measured every 2 weeks during this period. Mice were then sacrificed for podometric and histopathology analysis. Results: LPD offspring had significantly lower birth weights than NPD offspring (18% in males, p<0.01; 15% in females, p<0.01). Glomeruli in male LPD offspring were 23% smaller (p<0.0001) and had 15% fewer podocytes per glomerulus than male NPD offspring (62AE1.4 vs 72AE2.1 podocytes/glomerulus, p<0.001). In contrast, glomeruli in female LPD offspring were only 13% smaller (p<0.01) than female NPD offspring, with 9% fewer podocytes per glomerulus (61AE1.4 vs 67AE1.6, p<0.02). Male LPD diabetic offspring administered STZ had earlier onset of elevated urinary albumin excretion than male NPD diabetic offspring. Female LPD diabetic offspring had similar onset of elevated urinary albumin excretion to that of female NPD diabetic offspring. However, there was a trend for albumin excretion in female LPD diabetic mice to peak higher than that of female NPD diabetic mice (p=0.06). Conclusions: These findings demonstrate that low birth weight influences podocyte number in both male and female mice after the completion of nephrogenesis. Analysis of podocyte number and renal pathology in 24-week old offspring is continuing.