Common variation of the NSD1 gene is associated with susceptibility to Hirschsprung's disease in Chinese Han population.

BACKGROUND: Hirschsprung's disease (HSCR) is the most common congenital cause of intestinal obstruction in children. Sotos syndrome (SoS) is an overgrowth disorder with constipation and sometimes accompanied by HSCR. NSD1 gene mutation is the main cause of SoS. We aimed to investigate association of NSD1 common single nucleotide polymorphisms (SNPs) with HSCR susceptibility in Chinese Han population. METHOD: We genotyped 15 SNPs encompassing NSD1 gene region in 420 HSCR patients and 1665 controls on Fludigm EP1 platform. Association analysis was performed between cases and controls. RESULT: Rs244709 was the most associated SNP with HSCR susceptibility of the sample set (PAllelic = 9.69 × 10-5, OR = 1.37, 95% CI: 1.17-1.61). Gender stratification analysis revealed that NSD1 SNPs were associated with HSCR in males, but not in females. The nonsynonymous coding SNP rs28932178 in NSD1 exon 5 represented the most significant signal in males (PAllelic = 6.43 × 10-5, OR = 1.42, 95% CI: 1.20-1.69). The associated SNPs were expression quantitative trait loci (eQTLs) of nearby genes in multiple tissues. NSD1 expression levels were higher in aganglionic colon tissues than ganglionic tissues (P = 3.00 × 10-6). CONCLUSION: NSD1 variation conferred risk to HSCR in males, indicating SoS and HSCR may share common genetic factors. IMPACT: This is the first study to reveal that NSD1 variation conferred risk to Hirschsprung's disease susceptibility in males of Chinese Han population, indicating Sotos syndrome and Hirschsprung's disease may share some common genetic background. This study indicates more attention should be paid to the symptom of constipation in patients with Sotos syndrome. Our results raise questions about the role of NSD1 in the development of enteric nervous system and the pathogenesis of Hirschsprung's disease.

Emodin protects against oxidative stress and apoptosis in HK-2 renal tubular epithelial cells after hypoxia/reoxygenation.

The aim of the present study was to determine the effects of emodin, a natural compound with antioxidant properties, on oxidative stress and apoptosis induced by hypoxia/reoxygenation (H/R) in HK-2 human renal tubular cells. In HK-2 cells subjected to H/R, it was observed that pre-treatment with emodin lead to an increase in cellular viability and a reduction in the rate of apoptosis and the B-cell lymphoma 2 (Bcl-2)-associated X protein/Bcl-2 ratio. H/R alone caused a significant increase in the levels of reactive oxygen species and malondialdehyde (P<0.05) and a significant decrease in the activities of superoxide dismutase, catalase and glutathione peroxidase (P<0.05), relative to normoxic cells. In turn, parameters of oxidative stress were improved by emodin pre-treatment. In addition, emodin pre-treatment significantly inhibited the phosphorylation of extracellular signal-regulated protein kinase and c-Jun N-terminal kinase mitogen-activated protein kinases (MAPKs) induced by H/R (P<0.05). These data suggest that emodin may prevent H/R-induced apoptosis in human renal tubular cells through the regulation of cellular oxidative stress, MAPK activation and restoration of the Bax/Bcl-2 ratio.