Celastrol Ameliorates Systemic Lupus Erythematosus via Restoring Nt5e/ adenosine-dependent Th17/Treg Balance

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by the breakdown of immune tolerance, systemic inflammation, and multi-organ damage. The imbalance between T helper 17 (Th17) cells and regulatory T (Treg) cells is a key driver in SLE pathogenesis.

This study aimed to investigate whether Celastrol (Cel), a natural triterpenoid derived from Tripterygium wilfordii, exerts therapeutic effects in SLE by modulating the Th17/Treg balance, and to explore the underlying molecular mechanism.

An in vivo study using the MRL/lpr lupus-prone mouse model was conducted to evaluate therapeutic efficacy, complemented by in vitro assays and molecular analysis to identify target pathways.

MRL/lpr mice were orally administered Cel and disease progression was assessed via survival analysis, spleen pathology, autoantibody levels, and renal histopathology. T cell subsets were analyzed using flow cytometry and Western blot. Proteomic profiling was performed to identify potential molecular targets, followed by molecular docking, molecular dynamics simulations, cellular thermal shift assay (CETSA), MicroScale Thermophoresis (MST) and surface plasmon resonance (SPR) to validate target engagement. AB680, a pharmacological inhibitor of ecto-5'-nucleotidase (Nt5e), was used to confirm the functional role of Nt5e.

Cel treatment significantly improved survival, reduced splenomegaly, suppressed anti-dsDNA/ANA autoantibody levels, and alleviated renal damage in lupus-prone mice. It promoted Treg cell differentiation and inhibited Th17 polarization, evidenced by increased Foxp3 expression and decreased STAT3 phosphorylation. Nt5e was identified as a direct binding target of Cel. Target engagement was validated through CETSA, MST and SPR, and inhibition of Nt5e by AB680 partially reversed Cel's therapeutic effects, indicating that Nt5e mediates its immunomodulatory action.

Our results indicate that Cel restores the Th17/Treg balance via upregulating Nt5e, thereby ameliorating SLE-associated injury. This study thus provides novel insights into the mechanism of Cel treating SLE and underscores the therapeutic potential of targeting Nt5e in SLE.