Increased renal methylglyoxal formation with down-regulation of PGC-1α-FBPase pathway in cystathionine γ-lyase knockout mice.
We have previously reported that hydrogen sulfide (H(2)S), a gasotransmitter and vasodilator has cytoprotective properties against methylglyoxal (MG), a reactive glucose metabolite associated with diabetes and hypertension. Recently, H(2)S was shown to up-regulate peroxisome proliferator-activated receptor-γ coactivator (PGC)-1α, a key gluconeogenic regulator that enhances the gene expression of the rate-limiting gluconeogenic enzyme, fructose-1,6-bisphosphatase (FBPase). Thus, we sought to determine whether MG levels and gluconeogenic enzymes are altered in kidneys of 6-22 week-old cystathionine γ-lyase knockout (CSE(-/-); H(2)S-producing enzyme) male mice. MG levels were determined by HPLC. Plasma glucose levels were measured by an assay kit. Q-PCR was used to measure mRNA levels of PGC-1α and FBPase-1 and -2. Coupled-enzymatic assays were used to determine FBPase activity, or triosephosphate levels. Experimental controls were either age-matched wild type mice or untreated rat A-10 cells. Interestingly, we observed a significant decrease in plasma glucose levels along with a significant increase in plasma MG levels in all three age groups (6-8, 14-16, and 20-22 week-old) of the CSE(-/-) mice. Indeed, renal MG and triosephosphates were increased, whereas renal FBPase activity, along with its mRNA levels, were decreased in the CSE(-/-) mice. The decreased FBPase activity was accompanied by lower levels of its product, fructose-6-phosphate, and higher levels of its substrate, fructose-1,6-bisphosphate in renal extracts from the CSE(-/-) mice. In agreement, PGC-1α mRNA levels were also significantly down-regulated in 6-22 week-old CSE(-/-) mice. Furthermore, FBPase-1 and -2 mRNA levels were reduced in aorta tissues from CSE(-/-) mice. Administration of NaHS, a H(2)S donor, increased the gene expression of PGC-1α and FBPase-1 and -2 in cultured rat A-10 cells. In conclusion, overproduction of MG in CSE(-/-) mice is due to a H(2)S-mediated down-regulation of the PGC-1α-FBPase pathway, further suggesting the important role of H(2)S in the regulation of glucose metabolism and MG generation.
Department of Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
Ashley A
AA
Untereiner
Arti
A
Dhar
Jianghai
J
Liu
Lingyun
L
Wu
D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D002460:Cell Line; D002851:Chromatography, High Pressure Liquid; D003542:Cystathionine gamma-Lyase / Q000235:genetics / Q000378:metabolism*; D017931:DNA Primers; D015536:Down-Regulation; D006597:Fructose-Bisphosphatase / Q000235:genetics / Q000378:metabolism*; D007668:Kidney / Q000201:enzymology / Q000378:metabolism*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D011765:Pyruvaldehyde / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D060888:Real-Time Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D001786:Blood Glucose; D017931:DNA Primers; D012333:RNA, Messenger; D014157:Transcription Factors; C111264:peroxisome-proliferator-activated receptor-gamma coactivator-1; D011765:Pyruvaldehyde; D006597:Fructose-Bisphosphatase; D003542:Cystathionine gamma-Lyase