engleski

Chloride formate exchanger (CFEX - slc26a6) in rat organs ; sex-dependent expression in kidneys

In mammalian organs, transport of chloride, bicarbonate, oxalate, formate and hydroxyl ion is mediated by the chloride/formate exchanger Slc26a6 (CFEX). Most information about this transporter is known from the studies in mice, whereas its presence in various rat organs has been poorly studied. Here we investigated the presence and possible sex-related expression of CFEX protein and mRNA in various rat organs by qRT-PCR and immunochemical methods, respectively. Specificity of the commercial polyclonal anti-CFEX antibody was confirmed in HEK293 cells transiently transfected with the rat CFEX cDNA ; the antibody strongly stained the plasma membrane of CFEX-transfected cells, whereas the mock-transfected cells remained unstained. Thereafter, the CFEX protein was immunolocalized to 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. By Western blotting of total cell membranes isolated from these organs, the antibody labeled a single protein band of ~120 kDa. The CFEX mRNA expression in most organs followed the protein expression. In the liver, the expression of mRNA was similar in male and female rats. In the gastrointestinal tract, the mRNA expression was highest in duodenum, followed by jejunum and ileum, and sex-independent, and negligible in stomach, caecum and colon. In the kidneys, the CFEX protein and mRNA expression was zone-dependent (cortex < outer stripe), and exhibited sex differences in protein (males > females) but not mRNA (males = females) expression. The renal CFEX protein expression was low and sex-independent in prepubertal rats, whereas in adult animals, it was downregulated by castration and unaffected by ovariectomy. Therefore, CFEX is expressed in various rat organs, whereas in kidneys, the male-dominant protein expression appears after puberty due to androgen stimulation.

Chloride formate exchanger ; CFEX - slc26a6 ; rat

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