d‐Penicillamine modulates hydrogen sulfide (H₂S) pathway through selective inhibition of cystathionine‐γ‐lyase

Abstract

BACKGROUND AND PURPOSEHydrogen sulfide (H 2 S) is a gasotransmitter produced from L-cysteine through the enzymatic action of cystathionine-γ-lyase (CSE) and/or cystathionine-β-synthase. D-Penicillamine is the D isomer of a dimethylated cysteine and has been used for the treatment of rheumatoid arthritis. As D-penicillamine is structurally very similar to cysteine, we have investigated whether D-penicillamine, as a cysteine analogue, has an effect on the H 2 S pathway. EXPERIMENTAL APPROACHWe tested the effect of D-penicillamine (0.01-1 mM) in mouse aortic rings mounted in isolated organ baths and determined whether it could affect H 2 S biosynthesis. In particular, we investigated any possible inhibitor or donor behaviour by using recombinant enzyme-based assays and an in vivo approach. KEY RESULTSD-Penicillamine, per se, showed little or no vasodilator effect, and it cannot be metabolized as a substrate in place of L-cysteine. However, D-penicillamine significantly reduced L-cysteine-induced vasodilatation in a concentration-dependent manner through inhibition of H 2 S biosynthesis, and this effect occurred at concentrations 10 times lower than those needed to induce the release of H 2 S. In particular, D-penicillamine selectively inhibited CSE in a pyridoxal-5′-phospate-dependent manner. CONCLUSIONS AND IMPLICATIONSTaken together, our results suggest that D-penicillamine acts as a selective CSE inhibitor, leading to new perspectives in the design and use of specific pharmacological tools for H 2 S research. In addition, the inhibitory effect of D-penicillamine on CSE could account for its beneficial action in rheumatoid arthritis patients, where H 2 S has been shown to have a detrimental effect. AbbreviationsMPST, 3-mercaptopyruvate sulfurtransferase; CBS, cystathionine-β-synthase; CSE, cystathionine-γ-lyase; DPD, N,N-dimethylp-phenylenediamine sulfate; D-pen, D-penicillamine; L-pen, L-penicillamine; H 2 S, hydrogen sulfide; IVM, intravital microscopy; PAG, D,L-propargylglycine; PE, phenylephrine; PLP, pyridoxal-5′-phosphate; RA, rheumatoid arthritis; TCA, trichloroacetic acid; ZnAc, zinc acetate BJP IntroductionHydrogen sulfide (H 2 S) is a gaseous molecule endogenously synthesized by cystathionine-γ-lyase (CSE), cystathionine-β-synthase (CBS) and 3-mercaptopyruvate sulfurtransferase (MPST). These enzymes are differently distributed throughout the human body and within cell compartments. MPST is mainly expressed in mitochondria (Stipanuk, 2004;Shibuya et al., 2009), while CSE and CBS show a wide distribution in diverse cell types. CSE and CBS can both metabolize the substrate L-cysteine to release H 2 S, and this reaction is strictly dependent upon the enzyme cofactor pyridoxal-5′-phosphate (PLP). The role of H 2 S has been widely investigated in several organs and tissues, and many studies have confirmed its crucial role in body physiology. For instance, CSE represents the prominent enzyme within the cardiovascular system, where H 2 S is a major player involved in regulating the function of heart and bloo...

Hydrogen Sulfide as Potential Regulatory Gasotransmitter in Arthritic Diseases

“…This inhibitory activity may account for the potential anti-inflammatory effect of H 2 S in inflammatory arthritis. Moreover, the NF-κB pathway was inhibited by H 2 S in different experimental studies [117,125]. Hence, the anti-inflammatory role is highly probably secondary to the inhibition of the transcription factor NF-κB, which has a key role in the pathogenesis of inflammatory arthritis as described above (see Figures 2 and 3) [126,127]; furthermore, it can induce the synthesis of the anti-inflammatory cytokine IL-10 [106].…”

“…In addition, H 2 S concentration in the bloodstream was increased in patients with RA, and it was also associated with high numbers of circulating leukocytes [13]. As further support of a possible pathogenic role in inflammation, d-penicillamine, used in the past for the treatment of RA, resulted as a direct inhibitor of the synthesis of H 2 S and as a direct inhibitor of CSE activity [117]. In particular circumstances, the pro-inflammatory effect of H 2 S seems to be mediated by the induction of the expression of the intracellular adhesion molecule (ICAM)1, which may increase cell migration into the inflamed tissues [118].…”

Hydrogen sulfide dysregulates the immune response by suppressing central carbon metabolism to promote tuberculosis

“…Hence, our findings highlight the H 2 S-producing enzyme CSE as a potential therapeutic target to restrain TB disease. For example, D-Penicillamine (Cuprimine), which is commonly used to treat rheumatoid arthritis, targets CSE (36). H 2 S exerts a wide variety of biological pleiotropic functions because of its biphasic character.…”

The novel H2S donor 4‐carboxy‐phenyl isothiocyanate inhibits mast cell degranulation and renin release by decreasing intracellular calcium

“…We found that the CSE precursor, L‐cysteine (1–10 mM), elicited a concentration‐dependent inhibition of the degranulation caused by FcεRI activation in RBL‐2H3 cells. The selective CSE inhibitor D‐Pen (1 mM)(Brancaleone et al , ) significantly antagonized the effect of 10 mM concentration of L‐cysteine (Figure B). The expression of CSE, in the presence of antigen and of increasing concentrations of L‐cysteine, did not differ from control values, indicating that the inhibitory effect of L‐cysteine was not due to a change in CSE expression (Figure C).…”

“…inhibitor D-Pen (1 mM) (Brancaleone et al, 2016) significantly antagonized the effect of 10 mM concentration of L-cysteine ( Figure 2B). The expression of CSE, in the presence of antigen and of increasing concentrations of L-cysteine, did not differ from control values, indicating that the inhibitory effect of Lcysteine was not due to a change in CSE expression ( Figure 2C).…”