Identification of Isoliensinine as a Novel CCR5 Inhibitor for the Prevention of Skeletal Muscle Atrophy Through Virtual Screening and Experimental Validation.

Age-related skeletal muscle atrophy (sarcopenia) poses a major public health challenge, emphasizing the need for safe and effective interventions. Our previous studies demonstrated that C-C chemokine receptor type 5 (CCR5) is a key therapeutic target for skeletal muscle atrophy, as its activation by C-C motif chemokine ligand 11 (CCL11) promotes the dissociation and degradation of the structural protein α-actin, ultimately contributing to muscle loss. To identify potential CCR5 inhibitors, a database of 7860 natural alkaloids was constructed for pharmacophore-based virtual screening using the CCR5-Maraviroc crystal structure. Screening yielded 789 candidates, and subsequent batch molecular docking analysis identified Isoliensinine (ISO), a lotus seed alkaloid, as a potential CCR5 inhibitor with low binding energy (-10 kcal/mol) and stable hydrogen bonding interactions with Glu283 and Tyr251. Molecular dynamics simulations further confirmed the structural stability of the ISO-CCR5 complex. Molecular dynamics simulations further confirmed the structural stability of the ISO-CCR5 complex. In vitro, ISO dose-dependently inhibited CCL11-induced CCR5 activity (IC50 = 1.314 μM) with low cytotoxicity in C2C12 myotubes, and markedly alleviated CCL11-induced myotube atrophy by suppressing CCR5 activation and the upregulation of the muscle atrophy-related markers MAFbx and MuRF1. These findings provide preliminary evidence for ISO as a potential CCR5-targeting candidate for further investigation in sarcopenia.