A Direct Link Implicating Loss of SLC26A6 to Gut Microbial Dysbiosis, Compromised Barrier Integrity, and Inflammation

Abstract

BackgroundPutative anion transporter-1 (PAT1, SLC26A6) plays a key role in intestinal oxalate and bicarbonate secretion. PAT1 knockout (PKO) mice exhibit hyperoxaluria and nephrolithiasis. Notably, diseases such as inflammatory bowel diseases (IBD) are also associated with higher risk of hyperoxaluria and nephrolithiasis. However, the potential role of PAT1 deficiency in gut barrier integrity and susceptibility to colitis is currently elusive. MethodsAge-matched PKO and wild-type (WT) littermates were administered 3.5%-DSS in drinking water for 6 days. Ileum and colon of control and treated mice were harvested. mRNA and protein expression of tight junction (TJ) proteins were determined by RT-PCR and western blotting. Severity of inflammation was assessed by measuring diarrheal phenotype, cytokine expression and H&E staining. Gut microbiome and associated metabolome were analyzed by 16S rRNA sequencing and mass spectrometry, respectively. ResultsPKO mice exhibited significantly higher loss of body weight, gut permeability, colonic inflammation, and diarrhea in response to DSS treatment. Additionally, PKO mice showed microbial dysbiosis and significantly reduced levels of butyrate and butyrate-producing microbes compared to controls. Cohousing WT and PKO mice for 4 weeks resulted in PKO-like signatures on the expression of TJ proteins in the colon of WT mice. ConclusionOur data demonstrate that loss of PAT1 disrupts gut microbiome and related metabolites, decreases gut barrier integrity, and increases host susceptibility to intestinal inflammation. These findings, thus, highlight a novel role of the oxalate transporter PAT1 in promoting gut barrier integrity and its deficiency appears to contribute to the pathogenesis of IBD.