title: Carbon monoxide (CO) protects renal tubular epithelial cells against cold-rewarm apoptosis.
abstract: Recent studies have suggested that carbon monoxide (CO) inhalation can reduce ischemia-reperfusion injury of kidneys. The purpose of the present study was to determine whether the direct application of CO using tricarbonylchloro (glycinato) ruthenium II (CORM3) would reduce cold-rewarm-associated apoptosis in renal tubular epithelial (RPTE) cells. RPTE cells were subjected to 48 hours of cold followed by 24 hours of rewarming with increasing concentrations (0-500 microM) of CORM3. CORM3 (100 microM) reduced apoptosis as determined by the TUNEL method from 21.6 +/- 5.2 to 5.8 +/- 1.1 % (untreated vs. treated, n = 5; p < 0.001). We subsequently observed that the incubation of RPTE cells with CORM3 induced heme oxygenase (HO)-1 gene expression. As HO-1 itself can confer protection against cold rewarm injury, we investigated the role of HO-1 in the protective actions of CORM3 using siRNA oligonucleotides directed against HO-1. CORM3 treatment of RPTE cells caused a 4.9- fold increase in HO-1 gene expression as determined by real time PCR. Prior treatment of RPTE cells with siRNAs against HO-1 was able to completely abolish the CORM3 mediated induction of HO-1 mRNA and protein. The abolition of HO-induction with siRNAs did reduce CORM3-mediated protection against cold rewarm-induced apoptosis; however, CORM3 was able to significantly protect RPTE cells against cold-rewarm injury: apoptosis was 33.7 +/- 0.9% vs. 15.4 +/- 0.5% vs. 62.8 +/- 1.5% vs. 23.5 +/- 3.4 in control cold-rewarm vs. cold-rewarm + CORM3 (100 microM) vs. cold-rewarm + HO-1 siRNA vs. cold-rewarm + CORM3 (100 microM) + HO-1 siRNA (n = 4). These results suggest that increased levels of CO alone can protect against cold-rewarm-induced apoptosis.
authors.affiliation: Department of Physiology & Biophysics, Center for Excellence in Cardiovascular-Renal Research, University of Mississippi Medical Center, Jackson, Mississippi 39216-4505, USA. dstec@physiology.usmed.edu
authors.forename: David E
authors.initials: DE
authors.lastname: Stec
authors.forename: Christopher
authors.initials: C
authors.lastname: Bishop
authors.forename: John M
authors.initials: JM
authors.lastname: Rimoldi
authors.forename: Sambasiva R
authors.initials: SR
authors.lastname: Poreddy
authors.forename: Trinity
authors.initials: T
authors.lastname: Vera
authors.forename: Abdulla K
authors.initials: AK
authors.lastname: Salahudeen
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D002248:Carbon Monoxide / Q000494:pharmacology* / Q000627:therapeutic use; D002478:Cells, Cultured; D003080:Cold Temperature; D004847:Epithelial Cells / Q000187:drug effects*; D006801:Humans; D007684:Kidney Tubules / Q000166:cytology*; D009942:Organometallic Compounds / Q000494:pharmacology / Q000627:therapeutic use; D017694:Rewarming
chemical_list: D009942:Organometallic Compounds; C476530:tricarbonylchloro(glycinato)ruthenium(II); D002248:Carbon Monoxide