RESUMEN
Antisense Noncoding RNA in the INK4 Locus (ANRIL) is the prime candidate gene at Chr9p21, the well-defined genetic risk locus associated with multiple human diseases including coronary artery disease (CAD), while little is known regarding its role in the pathological processes. Endothelial dysfunction triggers atherosclerotic processes that are causatively linked to CAD. To evaluate the function of ANRIL in human endothelial cells (ECs), we examined ANRIL expression under pathological stimuli and found ANRIL was markedly induced by pro-inflammatory factors. Loss-of-function and chromatin immunoprecipitation approaches revealed that NF-κB mediates TNF-α induced ANRIL expression. RNA sequencing revealed that ANRIL silencing dysregulated expression of inflammatory genes including IL6 and IL8 under TNF-α treatment. We explored the regulatory mechanism of ANRIL on IL6/8 and found that Yin Yang 1 (YY1), an ANRIL binding transcriptional factor revealed by RNA immunoprecipitation, was required for IL6/8 expression under TNF-α treatment. YY1 was enriched at promoter loci of IL6/8 and ANRIL silencing impaired the enrichment, indicating a cooperation between ANRIL and YY1 in the regulation of inflammatory genes. For the first time, we establish the connection between ANRIL and NF-κB pathway and show that ANRIL regulates inflammatory responses through binding with YY1. The newly identified TNF-α-NF-κB-ANRIL/YY1-IL6/8 pathway enhances understanding of the etiology of CAD and provides potential therapeutic target for treatment of CAD.
Asunto(s)
Células Endoteliales/inmunología , FN-kappa B/genética , ARN Largo no Codificante/genética , Factor de Necrosis Tumoral alfa/farmacología , Factor de Transcripción YY1/genética , Línea Celular , Células Endoteliales/efectos de los fármacos , Células Endoteliales de la Vena Umbilical Humana , Humanos , Interleucina-6/genética , Interleucina-8/genética , Regiones Promotoras Genéticas , Transducción de Señal/efectos de los fármacosRESUMEN
Dioscoreaceae, a kind of yam plant, has been recommended for treatment of chronic inflammatory conditions. However, the mechanisms are poorly defined. Methyl protodioscin (MPD) is one of the main bioactive components in Dioscoreaceae. Here, we aim to determine the mechanisms by which MPD ameliorates intestinal inflammation. Surgical intestinal specimens were collected from inflammatory bowel diseases (IBD) patients to perform organ culture. Experimental colitis was induced in mice by dextran sulfate sodium (DSS) or Citrobacter rodentium, and was then treated with MPD. NF-κB activation, expression of mucosal pro-inflammatory cytokines, disease severity, and epithelial proliferation/apoptosis were determined. Mouse crypts and Caco-2 monolayers were cultured to observe the effect of MPD upon intestinal epithelial differentiation and barrier function. We found that MPD increased the percentage of survival from high-dose DSS-(4%) treated mice, and accelerated mucosal healing and epithelial proliferation in low-dose DSS-(2.5%) treated mice characterized by marked reduction in NF-κB activation, pro-inflammatory cytokines expression and bacterial translocation. Consistently, MPD protected colonic mucosa from C. rodentium-induced colonic inflammation and bacterial colonization. In vitro studies showed that MPD significantly increased crypt formation and restored intestinal barrier dysfunction induced by pro-inflammatory cytokines. In conclusion, MPD ameliorates the intestinal mucosal inflammation by modulating the intestinal immunity to enhance intestinal barrier differentiation. MPD could be an alternative for treating chronic intestinal inflammatory diseases.