engleski

Cell localization and sex-related expression of chloride/formate exchanger (Cfex/Slc26a6) in rat organs

The chloride/formate exchanger Slc26a6/Cfex transports chloride, bicarbonate, oxalate, formate and hydroxyl ions in mammalian organs. In contrast to mice, Cfex expression in rat organs has been poorly studied. So, we investigated the cell localization and possible sex-related expression of Cfex in various rat organs at mRNA and protein level by quantitative RT-PCR (qRT-PCR), immunofluorescence analysis (IFC) and western blotting (WB), respectively. Specificity of the anti-CFEX antibody (CFEX-Ab) was verified by IFC in HEK293 cells transiently transfected with rCfex cDNA ; the CFEX-Ab strongly stained the plasma membrane of rCfex-transfected HEK293 cells, whereas this staining was not observed in mock-transfected cells. By IFC, the Cfex protein was localized in the brush-border membrane of renal proximal tubules (S1S2S3) and intestinal enterocytes (duodenumjejunum, ileum was negative), canalicular membrane of hepatocytes and apical domain of pancreatic ducts. WB analysis of total cell membranes isolated from respective organs detected a single protein band of 120 kDa whose density matched the IFC findings. The Cfex mRNA expression roughly followed protein expression. Sex-dependent expression of Cfex at mRNA (qRT-PCR) and protein (WB/IFC) level was exclusively detected in kidneys of adult rats (malesfemales), whereas in pre-pubertal rats its expression was low and sex-independent. Furthermore, renal Cfex protein expression was downregulated by castration and unaffected by ovariectomy. Finally, testosterone upregulated, while estrogen and progesterone had no effect on renal Cfex protein expression in castrated males. Thus, Cfex is expressed in various rat organs, with male-dominant expression in kidneys that appears after puberty due to androgen stimulation.Funded by Croatian Science Foundation-project#1481.

membrane transporters ; immunolocalization ; rat organs ; sex differences

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