Background: To investigate the role and the underlying mechanisms of Calcium/calmodulin-dependent protein kinase Iα (CaMKIα) in modulating inflammatory responses during acute lung injury (ALI) via the AMPK/Sirtuin 3 (SIRT3) signaling pathway.

Methods: Neonatal rats were intratracheally administered Lipopolysaccharide (LPS) to induce ALI, while L2 alveolar epithelial cells were treated with LPS (100 ng/mL) in vitro. CaMKIα expression was silenced using siRNA in L2 cells and via AAV2/9-shRNA in rats. AMP-activated protein kinase (AMPK) activity was inhibited with Compound C (5 μM) in vitro. Pulmonary histopathology, bronchoalveolar lavage fluid cytokine levels, and key AMPK/SIRT3 pathway protein expressions were assessed.

Results: CaMKIα knockdown significantly alleviated lung injury in ALI rats, and significantly reduced lung edema, inflammatory cytokine levels, and histological injury (all p < 0.05). In vitro, CaMKIα knockdown enhanced L2 cell viability, suppressed apoptosis, and reduced pro-inflammatory cytokine production (all p < 0.05) via AMPK/SIRT3 activation. Inhibition of AMPK with Compound C abolished these protective effects (p < 0.05), confirming the involvement of this pathway.

Conclusion: CaMKIα attenuates inflammatory responses in ALI through activation of the AMPK/SIRT3 axis, indicating it may serve as a promising target for ALI therapy.