β-Sitosterol Alleviates the Proliferation and Migration of Cystitis Glandularis-Associated Cells by Targeting HMGCR to Induce NLRP3-Dependent Pyroptosis.

BACKGROUND

Cystitis glandularis (CG) is a proliferative lesion of the bladder mucosa, and the incidence rate of CG has increased year by year. Considering the potential function of β-sitosterol in CG, we aim to fathom its effect and mechanism of CG.

METHODS

Primary human cells isolated from CG patients and following transfection as needed, were treated with different concentrations of β-sitosterol. Cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and transwell assay was used to test the cell migration. Meanwhile, co-immunoprecipitation was employed to evaluate the interaction between 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) and NLR family pyrin domain containing 3 (NLRP3). Additionally, pyroptosis-associated proteins and HMGCR expressions were tested using western blot or quantitative real-time reverse transcription polymerase chain reaction.

RESULTS

β-sitosterol suppressed cell viability and migration, enhanced cell pyroptosis, and upregulated expressions of NLRP3, Cleaved Caspase-1, interleukin-1β (IL-1β), gasdermin D-N-terminal domain (GSDMD-N), and HMGCR in CG primary cells (p < 0.05). HMGCR silencing promoted cell viability and migration, inhibited cell pyroptosis, and downregulated expressions of NLRP3, Cleaved Caspase-1, IL-1β, and GSDMD-N in β-sitosterol-affected CG primary cells (p < 0.05). HMGCR interacted with NLRP3.

CONCLUSIONS

β-sitosterol alleviates the proliferation and migration of CG-associated cells by targeting HMGCR to induce NLRP3-dependent pyroptosis. These findings confirmed the therapeutic effect of β-sitosterol on treating CG.