BACKGROUND: This study investigated the influence of salt intake on the nephron specific gene expression of the kidney chloride channel CLC-K2. To this end, male Sprague-Dawley rats were fed a low (0.02% wt/wt), normal (0.6% wt/wt), or high salt (8% wt/wt) diet for ten days, or they received the loop diuretic furosemide (12 mg/kg/day) for six days. METHODS: Expression and regulation of messenger RNA for CLC-K2 was demonstrated by RNase protection assay and in situ hybridization in kidney cortex, outer medulla and inner medulla. Tubular localization and regulation were determined precisely by reverse transcription-polymerase chain reaction (RT-PCR) and real time PCR of microdissected nephron segments. RESULTS: In situ hybridization analysis and RNase protection assay of the total kidney revealed a down-regulation of CLC-K2 mRNA in the high salt diet rats and an up-regulation of CLC-K2 mRNA in furosemide treated rats, which were restricted to the outer medulla. Microdissection of collagenase treated kidney revealed CLC-K2 mRNA expression in the outer medullary thick ascending limb (mTAL), cortical thick ascending limb (cTAL), distal convoluted tubule (DCT), connecting tubule and cortical collecting duct (CNT/CCD), and outer medullary collecting duct (OMCD), whereas no signals were detected in proximal convoluted and straight tubules (PCT and PST), descending thin limb from the outer medulla (dTL), descending and ascending thin limb from the inner medulla (TL), inner medullary collecting duct (IMCD) and glomeruli (glom). Using RT-PCR and real time PCR, the changing levels of CLC-K2 mRNA after furosemide treatment or high salt diet were restricted to the mTAL, whereas CLC-K2 mRNA levels in cTAL and OMCD were not changed in furosemide or high salt rats compared to time paired controls. CONCLUSIONS: Given that CLC-K2 expressed in the thick ascending limb of Henle's loop is responsible for net chloride reabsorption in this part of the nephron, our findings suggest that in states of surplus salt and in states of severe salt deprivation, selective regulation of CLC-K2 mRNA plays a role in the adaptation of the kidney to different salt loads.
BACKGROUND: This study investigated the influence of salt intake on the nephron specific gene expression of the kidney chloride channel CLC-K2. To this end, male Sprague-Dawley rats were fed a low (0.02% wt/wt), normal (0.6% wt/wt), or high salt (8% wt/wt) diet for ten days, or they received the loop diuretic furosemide (12 mg/kg/day) for six days. METHODS: Expression and regulation of messenger RNA for CLC-K2 was demonstrated by RNase protection assay and in situ hybridization in kidney cortex, outer medulla and inner medulla. Tubular localization and regulation were determined precisely by reverse transcription-polymerase chain reaction (RT-PCR) and real time PCR of microdissected nephron segments. RESULTS: In situ hybridization analysis and RNase protection assay of the total kidney revealed a down-regulation of CLC-K2 mRNA in the high salt diet rats and an up-regulation of CLC-K2 mRNA in furosemide treated rats, which were restricted to the outer medulla. Microdissection of collagenase treated kidney revealed CLC-K2 mRNA expression in the outer medullary thick ascending limb (mTAL), cortical thick ascending limb (cTAL), distal convoluted tubule (DCT), connecting tubule and cortical collecting duct (CNT/CCD), and outer medullary collecting duct (OMCD), whereas no signals were detected in proximal convoluted and straight tubules (PCT and PST), descending thin limb from the outer medulla (dTL), descending and ascending thin limb from the inner medulla (TL), inner medullary collecting duct (IMCD) and glomeruli (glom). Using RT-PCR and real time PCR, the changing levels of CLC-K2 mRNA after furosemide treatment or high salt diet were restricted to the mTAL, whereas CLC-K2 mRNA levels in cTAL and OMCD were not changed in furosemide or high saltrats compared to time paired controls. CONCLUSIONS: Given that CLC-K2 expressed in the thick ascending limb of Henle's loop is responsible for net chloride reabsorption in this part of the nephron, our findings suggest that in states of surplus salt and in states of severe salt deprivation, selective regulation of CLC-K2 mRNA plays a role in the adaptation of the kidney to different salt loads.
Authors: Mohammed Z Ferdaus; Karl W Barber; Karen I López-Cayuqueo; Andrew S Terker; Eduardo R Argaiz; Brandon M Gassaway; Régine Chambrey; Gerardo Gamba; Jesse Rinehart; James A McCormick Journal: J Physiol Date: 2016-05-29 Impact factor: 5.182
Authors: Konrad Wolf; Martina Meier-Meitinger; Tobias Bergler; Hayo Castrop; Helga Vitzthum; Günter A J Riegger; Armin Kurtz; Bernhard K Krämer Journal: Pflugers Arch Date: 2003-05-21 Impact factor: 3.657
Authors: Johannes Schödel; Bernd Klanke; Alexander Weidemann; Björn Buchholz; Wanja Bernhardt; Marko Bertog; Kerstin Amann; Christoph Korbmacher; Michael Wiesener; Christina Warnecke; Armin Kurtz; Kai-Uwe Eckardt; Carsten Willam Journal: Am J Pathol Date: 2009-04-06 Impact factor: 4.307