Correction of Ito in human induced pluripotent stem Cell-derived cardiomyocyte carrying DPP6 mutation in early repolarization syndrome by CRISPR/Cas9 genome editing.

Early repolarization syndrome (ERS) is defined as occurring in patients with early repolarization pattern who have survived idiopathic ventricular fibrillation with clinical evaluation unrevealing for other explanations. The pathophysiologic basis of the ERS is currently uncertain. The objective of the present study was to examine the electrophysiological mechanism of ERS utilizing induced pluripotent stem cells (iPSCs) and CRISPR/Cas9 genome editing. Whole genome sequencing was used to identify the DPP6 (c.2561T > C/p.L854P) variant in four families with sudden cardiac arrest induced by ERS. Cardiomyocytes were generated from iPSCs from a 14-year-old boy in the four families with ERS and an unrelated healthy control subject. Patch clamp recordings revealed more significant prolongation of the action potential duration (APD) and increased transient outward potassium current (Ito) (103.97 ± 18.73 pA/pF vs 44.36 ± 16.54 pA/pF at +70 mV, P < 0.05) in ERS cardiomyocytes compared with control cardiomyocytes. Of note, the selective correction of the causal variant in iPSC-derived cardiomyocytes using CRISPR/Cas9 gene editing normalized the Ito, whereas prolongation of the APD remained unchanged. ERS cardiomyocytes carrying DPP6 mutation increased Ito and lengthen APD, which maybe lay the electrophysiological foundation of ERS.

Serum electrolyte concentrations and risk of atrial fibrillation: an observational and mendelian randomization study.

BACKGROUND: Atrial fibrillation (AF) is a prevalent arrhythmic condition resulting in increased stroke risk and is associated with high mortality. Electrolyte imbalance can increase the risk of AF, where the relationship between AF and serum electrolytes remains unclear. METHODS: A total of 15,792 individuals were included in the observational study, with incident AF ascertainment in the Atherosclerosis Risk in Communities (ARIC) study. The Cox regression models were applied to calculate the hazard ratio (HR) and 95% confidence interval (CI) for AF based on different serum electrolyte levels. Mendelian randomization (MR) analyses were performed to examine the causal association. RESULTS: In observational study, after a median 19.7 years of follow-up, a total of 2551 developed AF. After full adjustment, participants with serum potassium below the 5th percentile had a higher risk of AF relative to participants in the middle quintile. Serum magnesium was also inversely associated with the risk of AF. An increased incidence of AF was identified in individuals with higher serum phosphate percentiles. Serum calcium levels were not related to AF risk. Moreover, MR analysis indicated that genetically predicted serum electrolyte levels were not causally associated with AF risk. The odds ratio for AF were 0.999 for potassium, 1.044 for magnesium, 0.728 for phosphate, and 0.979 for calcium, respectively. CONCLUSIONS: Serum electrolyte disorders such as hypokalemia, hypomagnesemia and hyperphosphatemia were associated with an increased risk of AF and may also serve to be prognostic factors. However, the present study did not support serum electrolytes as causal mediators for AF development.

[LLY-283 inhibits proliferation and metastasis of head and neck squamous cell carcinoma by targeting PRMT5].

PURPOSE: To explore the effect of LLY-283 on the biological behavior of Head and neck squamous cell carcinoma(HNSCC) proliferation and metastasis through protein arginine methyltransferase 5(PRMT5). METHODS: TCGA database was used to analyze the expression level of PRMT5 in HNSCC tissues and cell lines by RT-PCR and Western blot. Lentiviral technology was used to construct PRMT5 knockdown stable cell line, and analyze the effect of PRMT5 on the biological behavior of HNSCC. Drug killing experiment was used to observe the IC50 changes of LLY-283 in cell lines. Nude mouse xenograft experiments were further tested to observe the biological effects of LLY-283 on HNSCC through PRMT5. RESULTS: PRMT5 was highly expressed in HNSCC tissues and cell lines, which promoted the proliferation and metastasis of cell lines, and reduced the IC50 value of LLY-283. LLY-283 could significantly reduce the cell proliferation and metastasis, tumor volume and Ki-67 expression in nude mice in vivo of HNSCC through PRMT5. CONCLUSIONS: LLY-283 inhibits the expression of PRMT5 and Ki-67, thereby decreases the proliferation and metastasis of HNSCC and the ability to form transplanted tumors in nude mice, exerting anti-tumor effects.