Renal fibrosis is widely considered a common mechanism leading to end-stage renal failure. Epithelial-to-mesenchymal transition (EMT) plays important roles in the pathogenesis of renal fibrosis. Runt-related transcription factor 1(RUNX1) plays a vital role in hematopoiesis via Endothelial-to-Hematopoietic Transition (EHT), a process that is conceptually similar to EMT, but its role in EMT and renal fibrosis is unclear. Here, we demonstrate that RUNX1 is overexpressed in the processes of TGF-β-induced partial EMT and renal fibrosis and that the expression level of RUNX1 is SMAD3-dependent. Knockdown of RUNX1 attenuated both TGF-β-induced phenotypic changes and the expression levels of EMT marker genes in renal tubular epithelial cells (RTECs). In addition, overexpression of RUNX1 promoted the expression of EMT marker genes in renal tubular epithelial cells. Moreover, RUNX1 promoted TGF-β-induced partial EMT by increasing transcription of the PI3K subunit p110δ, which mediated Akt activation. Specific deletion of Runx1 in mouse RTECs attenuated renal fibrosis, which was induced by both unilateral ureteral obstruction (UUO) and folic acid (FA) treatment. These findings suggest that RUNX1 is a potential target for preventing renal fibrosis.

An appropriate inflammatory response plays critical roles in eliminating pathogens, whereas an excessive inflammatory response can cause tissue damage. Runt-related transcription factor 1 (RUNX1), a master regulator of hematopoiesis, plays critical roles in T cells; however, its roles in Toll-like receptor 4 (TLR4)-mediated inflammation in macrophages are unclear. Here, we demonstrated that upon TLR4 ligand stimulation by lipopolysaccharide (LPS), macrophages reduced the expression levels of RUNX1 Silencing of Runx1 attenuated the LPS-induced IL-1β and IL-6 production levels, but the TNF-α levels were not affected. Overexpression of RUNX1 promoted IL-1β and IL-6 production in response to LPS stimulation. Moreover, RUNX1 interacted with the NF-κB subunit p50, and coexpression of RUNX1 with p50 further enhanced the NF-κB luciferase activity. Importantly, treatment with the RUNX1 inhibitor, Ro 5-3335, protected mice from LPS-induced endotoxic shock and substantially reduced the IL-6 levels. These findings suggest that RUNX1 may be a new potential target for resolving TLR4-associated uncontrolled inflammation and preventing sepsis.

AIM: To investigate the relationship between gallbladder stone disease (GSD) and single nucleotide polymorphisms of cholesterol 7α-hydroxylase (CYP7A) gene promoter, apolipoprotein (APO) B gene exon 26, APOE gene exon 4 or microsatellite polymorphism of low density lipoprotein receptor (LDLR) gene exon 18. METHODS:Genotypes of CYP7A, APOB, APOE and LDLR genes were determined in 105 patients with GSD diagnosed by B-mode ultrasonography and 274 control subjects. Serum lipids were analyzed with HITACHI 7060 automaic biochemical analyzer. RESULTS:Body mass index (BMI) was significantly higher in patients with GSD (24.47±3.09) than in controls (23.50±2.16). Plasma total cholesterol was lower in patients with GSD (4.66±0.92 mmol/L) than in controls (4.91±0.96 mmol/L), P<0.01 after adjusted for age, sex and BMI. The significantly higher frequency of A allele of CYP7A gene polymorphism and X+ allele of APOB gene polymorphism was seen in GSD patients. Percentages of A allele in patients and controls were 62.86% and 54.38% (P <0.05) and those of X+ allele 8.57% and 4.01% (P<0.01). Subjects with A allele had significantly lower plasma total cholesterol and LDL cholesterol than subjects with CC homozygote. In a multiple variable logistic regression model, the BMI (OR=1.13, 95% CI: 1.05-1.22), A allele (OR=1.48, 95% CI: 1.05-2.09) and X+ allele (OR=2.28, 95% CI: 1.14-4.59) were positively associated with GSD (P <0.05). Plasma total cholesterol (OR=0.69, 95% CI: 0.64-0.74) was negatively related to GSD (P<0.05). CONCLUSION:With an association analysis, it was determined that A allele of CYP7A gene and X+ allele of APOB gene might be considered as risk genes for GSD. These alleles are related with differences of serum lipids among subjects. Multiple-variable logistic regression model analysis showed that besides BMI, GSD was affected by polygenetic factors. But the mechanism for these two alleles responsible for GSD requires further investigations.

In the pathological process of acute kidney injury (AKI), innate immune receptors are essential in inflammatory response modulation; however, the precise molecular mechanisms are still unclear. Our study sought to demonstrate the inflammatory response mechanisms in renal tubular epithelial cells via Toll-like receptor-4 (TLR-4) and dendritic cell-specific intercellular adhesion molecule 3-grabbing non-integrin 1 (DC-SIGN) signalling. We found that DC-SIGN exhibited strong expression in renal tubular epithelial cells of human acute renal injury tissues. DC-SIGN protein expression was increased significantly when renal tubular epithelial cells were exposed to lipopolysaccharide (LPS) for a short period. Furthermore, DC-SIGN was involved in the activation of p65 by TLR-4, which excluded p38 and c-Jun N-terminal kinases (JNK). Interleukin (IL)-6 and tumour necrosis factor (TNF)-α expression was decreased after DC-SIGN knock-down, and LPS induced endogenous interactions and plasma membrane co-expression between TLR-4 and DC-SIGN. These results show that DC-SIGN and TLR-4 interactions regulate inflammatory responses in renal tubular epithelial cells and participate in AKI pathogenesis.