Aims: Celastrol, a naturally occurring pentacyclic triterpene, has attracted considerable interest because it exhibits potent anti-inflammatory and anti-tumor properties. However, the effects of celastrol in autosomal dominant polycystic kidney disease (ADPKD) remain uninvestigated.
Main methods: We determined the effects of celastrol on ADPKD progression in a novel Pkd1-hypomorphic mouse model by intraperitoneal injection (postnatal day 35-63).
Key findings: Pkd1 miRNA transgenic (Pkd1 miR TG) mice treated with 1 mg/kg/day of celastrol exhibited a lower renal cystic index (by 21.5%) than the vehicle-treated controls, but the fractional kidney weights and blood urea nitrogen levels were not significantly affected with celastrol treatment. At a high dose (2 mg/kg/day), celastrol caused marginal weight loss in the treated mice and had no significant effect on renal cystogenesis, thus indicating a potential toxic effect. We further identified that celastrol increased the phosphorylation level of adenosine monophosphate-activated protein kinase (AMPK) in the cystic kidneys. Moreover, celastrol reduced the renal mRNA expression levels of tumor necrosis factor-α, interleukin-1β, P2RX7, F4/80, CD68, transforming growth factor-β, collagen-1, and fibronectin, which were high in the Pkd1 miR TG mice. Immunohistological analysis revealed that celastrol suppressed macrophage infiltration in the cystic kidneys; however, the renal fibrosis scores and proliferation indices remained high.
Significance: These results indicate that celastrol could be a potent anti-inflammatory agent and a natural AMPK enhancer. However, celastrol has only modest effects on renal cystogenesis and has a narrow therapeutic window. Further studies are needed to clarify whether celastrol has the potential for the treatment of ADPKD.
Keywords: Celastrol; Inflammation; Macrophage; Polycystic kidney disease.
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