Lactate programs CRIP1 protein lactylation to drive synovial proliferation in rheumatoid arthritis
Meican Ma, Yu Zhou, Qianlin Li, Zhao Wang, Shangqi Guan, Xiaoxue Wang, Han Zhao, Zhenke Wen, Ting Liu, Fenghong Yuan
Meican Ma, Yu Zhou, Qianlin Li, Zhao Wang, Shangqi Guan, Xiaoxue Wang, Han Zhao, Zhenke Wen, Ting Liu, Fenghong Yuan
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Research Article Metabolism

Lactate programs CRIP1 protein lactylation to drive synovial proliferation in rheumatoid arthritis

Abstract

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.

Authors

Meican Ma, Yu Zhou, Qianlin Li, Zhao Wang, Shangqi Guan, Xiaoxue Wang, Han Zhao, Zhenke Wen, Ting Liu, Fenghong Yuan

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Figure 5

MOF mediates CRIP1 protein lactylation and synovial proliferation in RA.

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MOF mediates CRIP1 protein lactylation and synovial proliferation in RA....
(A) Co-IP of CRIP1 followed by immunoblotting for Pan-Kla to detect CRIP1 protein lactylation in RA-FLSs after knockdown of lysine acetyltransferases (GCN5, PCAF, p300, Tip60, MOF, AARS1) (n = 3). (B) Co-IP of CRIP1 followed by immunoblotting for Pan-Kla to detect CRIP1 protein lactylation in RA-FLSs upon overexpression of lysine acetyltransferases (GCN5, PCAF, p300, Tip60, MOF, AARS1) (n = 3). (C and D) Co-IP assays to detect the interaction between CRIP1 and MOF (n = 3). (E and F) Immunofluorescence staining and quantification of CRIP1 (green) and MOF (yellow) in RA-FLSs. Scale bar: 20 μm. (G) Co-IP of CRIP1 followed by immunoblotting for Pan-Kla to detect CRIP1 protein lactylation in RA-FLSs expressing WT or K49R mutant. The assay was performed with or without MOF overexpression. (H and I) EdU incorporation and quantification of cell proliferation in RA-FLSs after MOF knockdown (n = 6). Scale bar: 100 μm. (J) CCK-8 assay evaluating proliferation in RA-FLSs after MOF knockdown (n = 6). (K and L) EdU incorporation and CCK-8 assay to quantify cell proliferation in RA-FLSs expressing Veh, WT, or CRIP1 K49R. These assays were performed with or without MOF overexpression (n = 6). **P < 0.01, ***P < 0.001, ****P < 0.0001. Data are shown as mean ± SEM and P-values are calculated using unpaired 2-tailed t test (I), or 2-way ANOVA with Bonferroni’s post hoc test (J and L), or 1-way ANOVA followed by Tukey’s post hoc test (K).