Yu Zhou

Synovial hyperplasia is a hallmark of rheumatoid arthritis (RA), yet its mechanism remains unclear. RA synovium exhibits metabolic shift, characterized by upregulated glycolysis and enhanced lactate production. In this study, we elucidated the mechanism underlying the roles of lactate metabolism and protein lactylation in RA pathology. In patients with RA, both lactate production and protein lactylation were elevated and showed a positive correlation with clinical disease activity. These changes were further implicated in driving synovial proliferation. Among the lactylated proteins, Cysteine-rich intestinal protein 1 (CRIP1) exhibited a marked increase in modification and played a central role in promoting synovial proliferation. Mechanistically, CRIP1 underwent MOF-mediated lactylation in RA synovial fibroblasts. Lactylated CRIP1 hijacked the cell-cycle regulator p21, disrupting its interaction with cyclin-dependent kinase 2 (CDK2), thereby facilitating the G1/S phase transition. Functionally, AAV-mediated delivery of a lactylation-deficient CRIP1 K49R significantly reduced synovial proliferation compared with WT CRIP1. Peptide-based interventions targeting CRIP1 K49 lactylation effectively inhibited synovial hyperplasia and disease severity in both Collagen II–induced arthritis (CIA) and humanized NSG chimeric models. Collectively, CRIP1 protein lactylation drives synovial proliferation in RA by hijacking p21 from CDK2, thereby facilitating cell cycle progression. Targeting this pathway may serve as a promising strategy for RA.

Background: Diabetic kidney disease (DKD) is the leading risk factor for end-stage renal disease (ESRD). Hydroxyurea (HU), a sickle cell disease (SCD) drug approved by FDA, shows protective effect in nephropathy. This study aims to understand whether the application of HU could be effective to treat DKD.Methods: The streptozotocin (STZ)-induced diabetic mice, and high glucose (HG)-treated human renal mesangial cells (HRMCs) were used to investigate the effect of HU on DKD. Serum creatinine and blood urea nitrogen levels reflecting renal function were evaluated. Histology was used to evaluate pathological changes. Indicators of inflammation and apoptosis were detected. Lastly, the mTOR-S6K pathway was explored by detecting the protein expression of S6K and phosphorylated S6K.Results: In STZ-induced diabetic mice, administration of HU (20 mg/kg) in drinking water for 16 weeks resulted in significant reductions in creatinine and urea nitrogen levels, alongside mitigating histopathological damage. Additionally, HU effectively suppressed the inflammatory response and apoptosis within the kidneys. HRMC cells were cultivated in HG conditions, and HU effectively attenuated the HG-induced inflammation and apoptosis. Moreover, HU treatment significantly inhibited the mTOR signaling pathway in both in both in vivo and in vitro experiments.Conclusion: This study unveils a new role of HU in alleviating diabetic kidney disease by modulating inflammation and apoptosis through the mTOR-S6K pathway. However, since HU did not significantly affect blood glucose levels, its therapeutic potential may be best realized when used in combination with standard antidiabetic therapies. Such a combination approach could simultaneously address hyperglycemia and renal dysfunction, offering a more comprehensive management strategy for DKD.