Fibrosis is the final common pathway leading to end-stage chronic kidney disease (CKD). However, the function of protein palmitoylation in renal fibrosis and the underlying mechanisms remain unclear. In this study, we observed that expression of the palmitoyltransferase ZDHHC18 was significantly elevated in unilateral ureteral obstruction (UUO) and folic acid–induced (FA-induced) renal fibrosis mouse models and was significantly upregulated in fibrotic kidneys of patients with CKD. Functionally, tubule-specific deletion of ZDHHC18 attenuated tubular epithelial cells’ partial epithelial-mesenchymal transition (EMT) and then reduced the production of profibrotic cytokines and alleviated tubulointerstitial fibrosis. In contrast, ZDHHC18 overexpression exacerbated progressive renal fibrosis. Mechanistically, ZDHHC18 catalyzed the palmitoylation of HRAS, which was pivotal for its translocation to the plasma membrane and subsequent activation. HRAS palmitoylation promoted downstream phosphorylation of MEK/ERK and further activated Ras-responsive element–binding protein 1 (RREB1), enhancing SMAD binding to the Snai1 cis -regulatory regions. Taken together, our findings suggest that ZDHHC18 plays a crucial role in renal fibrogenesis and represents a potential therapeutic target for combating kidney fibrosis.

Objective: Parthenolide (PTL) has a wide range of clinical applications owing to its anti-inflammatory and antitumor effects. To date, the antitumor effect of PTL on gallbladder cancer (GBC) remains largely unknown. Therefore, we aimed to investigate the biological effects of PTL on GBC. Methods: The cellular viability and proliferation of GBC-SD and NOZ cell lines after treatment with different concentrations of PTL were analyzed using the Cell Counting Kit-8 (CCK8)assay and colony formation assay. Apoptosis analysis was performed using flow cytometry. Hoechst staining was performed. RNA sequencing (RNA-seq) was performed to identify PTL-related genes and signalling pathways. Furthermore, we confirmed the involvement of these signalling pathways by qRT-PCR and western blotting. For the in-vivo experiments, a xenograft model was used to evaluate the effects of PTL on the proliferation of NOZ cells. Results: PTL significantly inhibited GBC cell growth in vitro and induced apoptosis in the GBC-SD and NOZ cell lines in a dose-dependent manner. RNA sequencing data showed that the immune response and mitogen-activated protein kinase (MAPK) signalling pathways are closely associated with PTL-induced gallbladder cancer cell apoptosis. PTL upregulated BAX, cleaved PARP-1, cleaved caspase-3, cleaved caspase-9, P53 and decreased the expression of BCL-2, phosphorylated ERK, and phosphorylated MEK in vitro. Tumour volume and weight were also suppressed by PTL in vivo. Moreover, the effects of PTL on GBC cells might be mediated by the MAPK pathway. Conclusion: PTL significantly inhibits gallbladder cancer cell proliferation and induces apoptosis through the MAPK pathway, which is a potential molecular reagent for treating GBC. However, further exploration is needed to verify the antitumor effects of PTL and its intracellular signalling mechanism.