Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:4.2.1.22 (cystathionine beta-synthase)
 965 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hydrogen sulfide (H(2)S), a regulatory gaseous molecule that is endogenously synthesized by cystathionine gamma-lyase (CSE) and/or cystathionine beta-synthase (CBS) from L-cysteine (L-Cys) metabolism, is a putative vasodilator, and its role in nitric oxide (NO) production is unexplored. Here, we show that at noncytotoxic concentrations, H(2)S was able to inhibit NO production and inducible NO synthase (iNOS) expression via heme oxygenase (HO-1) expression in RAW264.7 macrophages stimulated with lipopolysaccharide (LPS). Both H(2)S solution prepared by bubbling pure H(2)S gas and NaSH, a H(2)S donor, dose dependently induced HO-1 expression through the activation of the extracellular signal-regulated kinase (ERK). Pretreatment with H(2)S or NaHS significantly inhibited LPS-induced iNOS expression and NO production. Moreover, NO production in LPS-stimulated macrophages that are expressing CSE mRNA was significantly reduced by the addition of L-Cys, a substrate for H(2)S, but enhanced by the selective CSE inhibitor beta-cyano-L-alanine but not by the CBS inhibitor aminooxyacetic acid. While either blockage of HO activity by the HO inhibitor, tin protoporphyrin IX, or down-regulation of HO-1 expression by HO-1 small interfering RNA (siRNA) reversed the inhibitory effects of H(2)S on iNOS expression and NO production, HO-1 overexpression produced the same inhibitory effects of H(2)S. In addition, LPS-induced nuclear factor (NF)-kappaB activation was diminished in RAW264.7 macrophages preincubated with H(2)S. Interestingly, the inhibitory effect of H(2)S on NF-kappaB activation was reversed by the transient transfection with HO-1 siRNA, but was mimicked by either HO-1 gene transfection or treatment with carbon monoxide (CO), an end product of HO-1. CO treatment also inhibited LPS-induced NO production and iNOS expression via its inactivation of NF-kappaB. Collectively, our results suggest that H(2)S can inhibit NO production and NF-kappaB activation in LPS-stimulated macrophages through a mechanism that involves the action of HO-1/CO.
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PMID:Hydrogen sulfide inhibits nitric oxide production and nuclear factor-kappaB via heme oxygenase-1 expression in RAW264.7 macrophages stimulated with lipopolysaccharide. 1678 59

Butyrate is a short-chain fatty acid that arrests growth of various types of cells. H(2)S can be endogenously produced by cystathionine gamma-lyase (CSE) or cystathionine beta-synthase (CBS) or both in colonic tissues. In this study, we observed endogenous H(2)S production in a colon cancer cell line (WiDr) and colonic tissues through the activity of both CSE and CBS. After 24 h of incubation of WiDr cells, butyrate increased cell production of H(2)S and upregulated CBS and CSE expressions. Both butyrate and NaHS (a H(2)S donor) decreased cell viability in a dose-dependent manner. Blockade of CBS, but not CSE, decreased butyrate-stimulated H(2)S production and reversed butyrate-inhibited cell viability. In addition, NaHS treatment stimulated the phosphorylation of extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK), but not c-Jun N-terminal kinase (JNK). Inhibition of the phosphorylation of either p38 MAPK or ERK did not abolish NaHS-induced cell death. Butyrate treatment increased the phosphorylation of ERK, not p38 MAPK and JNK, but inhibition of ERK and p38 MAPK phosphorylation did not inhibit butyrate-reduced cell viability. In conclusion, butyrate regulates endogenous H(2)S production by stimulating CBS expression in colon cancer cells, but butyrate and H(2)S inhibit cancer cell growth through different mechanisms.
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PMID:Butyrate-stimulated H2S production in colon cancer cells. 1980 45