Discovery of a pyrrole-enone hybrid from deep-sea cold-seep-derived Aspergillus sp. exhibiting anti-renal fibrotic activity associated with the attenuation of p38 MAPK phosphorylation.

An unprecedented pyrrole-enone hybrid, asperidone A (1), featuring a highly congested 5/6/6/6 tetracyclic skeleton, together with one new enone stereoisomer of natural product, kojicone D (3), and one known analogue, was isolated from the deep-sea cold-seep-derived fungus Aspergillus sp. SCSIO41424. Their structures were elucidated by comprehensive spectroscopic analysis, X-ray crystallography, ECD calculations, and GIAO 13C NMR/DP4+ analysis. Under non-cytotoxic conditions (including TGF-β1 stimulation), compounds 1 and 3 (10 μM) significantly attenuated the expression of fibrotic markers, including fibronectin (FN) and α-smooth muscle actin (α-SMA), in TGF-β1-stimulated HK-2 cells. Immunofluorescence staining further confirmed that treatment with 1 downregulated α-SMA and COL1A1 levels. Furthermore, this antifibrotic cellular phenotype of compound 1 was validated in a complementary TCMK-1 cell model. Moreover, 1 attenuated TGF-β1-induced p38 phosphorylation without affecting Smad2/3 activation in HK-2 cells under the tested conditions. In silico molecular docking suggested potential interactions within the p38α ATP pocket, providing a structural hypothesis for the observed pathway response.