Association of microRNA polymorphisms with the risk of head and neck squamous cell carcinoma in a Chinese population:a case-control study

Background:MicroRNA(miRNA) polymorphisms may alter miRNA-related processes,and they likely contribute to cancer susceptibility.Various studies have investigated the associations between genetic variants in several key miRNAs and the risk of human cancers;however,few studies have focused on head and neck squamous cell carcinoma(HNSCC) risk.This study aimed to evaluate the associations between several key miRNA polymorphisms and HNSCC risk in a Chinese population.Methods:In this study,we genotyped five common single-nucleotide polymorphisms(SNPs) in several key miRNAs(miR-149 rs2292832,miR-146 a rs2910164,miR-605 rs2043556,miR-608 rs4919510,and miR-196a2 rs11614913) and evaluated the associations between these SNPs and HNSCC risk according to cancer site with a case-control study including 576 cases and 1552 controls,which were matched by age and sex in a Chinese population.Results:The results revealed that miR-605 rs2043556[dominant model:adjusted odds ratio(OR) 0.71,95%confidence interval(CI) 0.58-0.88;additive model:adjusted OR 0.74,95%CI 0.62-0.89]and miR-196a2 rs11614913(dominant model:adjusted OR 1.36,95%C11.08-1.72;additive model:adjusted OR 1.28,95%C11.10-1.48) were significantly associated with the risk of oral squamous cell carcinoma(OSCC).Furthermore,when these two loci were evaluated together based on the number of putative risk alleles(rs2043556 A and rs11614913 G),a significant locus-dosage effect was noted on the risk of OSCC(P_(trend) < 0.001).However,no significant association was detected between the other three SNPs(miR-149 rs2292832,miR- 146 a rs2910164,and miR-608 rs4919510) and HNSCC risk.Conclusion:Our study provided the evidence that miR-605 rs2043556 and miR-196a2 rs11614913 may have an impact on genetic susceptibility to OSCC in Chinese population.

Gingipain from Porphyromonas gingivalis causes insulin resistance by degrading insulin receptors through direct proteolytic effects

Periodontitis is a critical risk factor for the occurrence and development of diabetes.Porphyromonas gingivalis may participate in insulin resistance(IR)caused by periodontal inflammation,but the functional role and specific mechanisms of P.gingivalis in IR remain unclear.In the present study,clinical samples were analysed to determine the statistical correlation between P.gingivalis and IR occurrence.Through culturing of hepatocytes,myocytes,and adipocytes,and feeding mice P.gingivalis orally,the functional correlation between P.gingivalis and IR occurrence was further studied both in vitro and in vivo.Clinical data suggested that the amount of P.gingivalis isolated was correlated with the Homeostatic Model Assessment for IR score.In vitro studies suggested that coculture with P.gingivalis decreased glucose uptake and insulin receptor(INSR)protein expression in hepatocytes,myocytes,and adipocytes.Mice fed P.gingivalis tended to undergo IR.P.gingivalis was detectable in the liver,skeletal muscle,and adipose tissue of experimental mice.The distribution sites of gingipain coincided with the downregulation of INSR.Gingipain proteolysed the functional insulin-binding region of INSR.Coculture with P.gingivalis significantly decreased the INSR–insulin binding ability.Knocking out gingipain from P.gingivalis alleviated the negative effects of P.gingivalis on IR in vivo.Taken together,these findings indicate that distantly migrated P.gingivalis may directly proteolytically degrade INSR through gingipain,thereby leading to IR.The results provide a new strategy for preventing diabetes by targeting periodontal pathogens and provide new ideas for exploring novel mechanisms by which periodontal inflammation affects the systemic metabolic state.