CBS and renal fibrosis: Moreover, CBS-derived H2S may be relevant in maintaining homeostasis in the kidney under normal conditions and may be suppressed under pathological conditions, because the amount of CBS protein level in proximal tubules was considerably and immediately reduced after UUO injury, while CSE expression in the renal interstitium was compensatorily enhanced and CSE inhibitor DL-propargylglycine (PAG) aggravated renal fibrosis [13].