Chemoproteomics of Marine Natural Product Naamidine J Unveils CSE1L as a Therapeutic Target in Acute Lung Injury.

Acute lung injury is a devastating illness characterized by severe inflammation mediated by aberrant activation of macrophages, resulting in significant morbidity and mortality, highlighting the urgent need for novel pharmacological targets and drug candidates. In this study, we identified a novel target for regulating inflammation in macrophages and acute lung injury via chemical proteomics and genetics based on a marine alkaloid, naamidine J (NJ). The structures of NJ-related naamidine alkaloids were first confirmed or revised by a combination of quantum chemical calculations and X-ray diffraction analysis. NJ was found as a potential anti-inflammatory agent by screening our compound library, and CSE1L was identified by chemoproteomics as a main cellular target of NJ to inhibit inflammation in macrophages and protect against acute lung injury. Mechanistically, we demonstrated that NJ directly interacted with CSE1L on the sites of His745 and Phe903 and then inhibited the nuclear translocation and transcriptional activity of transcription factor SP1, thereby suppressing inflammation in macrophages and ameliorating acute lung injury. Taken together, these findings have uncovered a novel pharmacological target for the treatment of acute lung injury and have also provided a potential druggable pocket of CSE1L and a lead compound or an available chemical tool from marine sources for investigating CSE1L function and developing novel drug candidates against acute lung injury.

Design, synthesis and in vitro biological evaluation of marine phidianidine derivatives as potential anti-inflammatory agents.

Phidianidines A and B are novel marine indole alkaloids with various biological activities. Based on their potential anti-inflammatory properties, a series of phidianidine derivatives were designed, synthesized, and tested for their effects on IL-17A production in PMA/ionomycin-stimulated T-cell-lymphoma EL-4 cells. Compounds 9a and 22c exhibited excellent anti-inflammatory activity and low toxicity, with IC50 values of 7.7 µM and 5.3 µM for IL-17A production in PMA/ionomycin-stimulated EL-4 cells, respectively. Further mechanistic study showed that 9a could decrease the STAT3 phosphorylation at Y705 to inhibit IL-17A production in EL-4 cells, indicating its ability of preventing the differentiation of Th17 cells and their possible function. This research may give an insight for the discovery of marine indole alkaloid derived anti-inflammatory drug leads for the treatment of T cell-mediated diseases.