KLF4 interacts with TXNIP to modulate the pyroptosis in ulcerative colitis via regulating NLRP3 signaling

Ulcerative colitis (UC) is one of the most common diseases in the gastrointestinal tract related to abnormal inflammation. Pyroptosis, which is characterized by the formation of inflammasome, activation of caspase-1, and separation of N- and C-terminus of gasdermin D (GSDMD), and may be involved in the pathogenesis of IBD. Krüppel-like factor 4 (KLF4) is a zinc finger transcription factor expressed in differentiated epithelial cells. KLF4 mediates proinflammatory signaling in macrophages. Here, we tested whether KLF4 is functional in pyroptosis of UC.

In human UC tissues and/or lipopolysaccharide (LPS)/adenosine 5-triphosphate (ATP) stimulation human colon epithelial cells, KLF4, TXNIP, Cleave-Caspase-1, and GSDMD expression were detected through quantitative reverse transcription polymerase chain reaction (PCR), immunohistochemical and western blot assay. Interleukin (IL)-1β and IL-18 levels were quantified by enzyme-linked immunosorbent assay. We successfully constructed a KLF4-silenced colon epithelial cell line using an adenovirus vector. We apply the UCSC and JASPAR to predict the KLF4 binding sites in the promoter region of TXNIP.

In human UC tissues and/or LPS/ATP stimulation human colon epithelial cells, KLF4, TXNIP, Caspase-1, and GSDMD expression level were significantly elevated via quantitative reverse transcription PCR, immunohistochemical and western blot assay. Moreover, We identified that there is an interaction between KLF4 and TXNIP through Yeast double hybrid assay and CO-IP assay. We successfully constructed a KLF4-silenced human intestinal epithelial cell line. In LPS/ATP stimulation KLF4-silenced human intestinal epithelial cells, KLF4, TXNIP, Cleave Caspase-1, ASC, and GSDMD expression level were significantly decreased via quantitative reverse transcription PCR.

Our results confirm that KLF4 can positively regulate the expression of TXNIP and regulate the pyroptosis process of UC through the TXNIP/NLRP3 pathway.