Attenuation of cGAS-STING signaling-mediated lung inflammation during infection through autophagy induction by bioactive nanodevices.

BACKGROUND: Modulating the cGAS-STING pathway by bioactive nanodevices is a promising strategy for combating infection-associated inflammatory disorders. However, the development of pharmacological inhibitors for cGAS-STING signaling is currently hindered by lacking cell-specific targeting capability. This study aimed to develop a potent, drug-free nanodevice that specifically targets pulmonary macrophages to modulate the cGAS-STING pathway for ameliorating infection-associated detrimental lung inflammation.

METHODS: Cigarette smoke extract-modified peptide gold nanoparticle hybrids (CSE-P12) were synthesized. Transcriptomic analysis, western blotting, autophagy reporter assays, and confocal microscopy were employed to assess the effects of CSE-P12 on gene expression, STING degradation, autophagic flux, and inflammation. TEM imaging and LC-MS/MS were utilized to elucidate the molecular mechanisms underlying CSE-P12-induced autophagy in macrophages. Finally, the HAdV4-induced pneumonia and CLP-induced sepsis models on wild-type and STING-/- mice were used to evaluate the therapeutic efficacy of CSE-P12 and validate its inhibitory mechanisms on the cGAS-STING pathway.

RESULTS: CSE-P12 nanodevices are extensively internalized by macrophages via energy-dependent cellular uptake. This large internalization triggers autophagic degradation of STING, thereby effectively inhibiting the cGAS-STING-mediated interferon responses and inflammation. In the HAdV4-induced viral pneumonia mouse model, intratracheally instilled CSE-P12 effectively targets pulmonary macrophages, suppresses STING activation, and significantly alleviates lung inflammation and injury. The depletion of the pulmonary macrophages abolishes these protective effects. The therapeutic potential of CSE-P12 is further validated in a CLP-induced polymicrobial sepsis mouse model, where it significantly prolongs mouse survival and decreases lung inflammation.

CONCLUSIONS: CSE-P12 effectively targets pulmonary macrophages and exhibits potent anti-inflammatory activities in viral pneumonia and sepsis-induced acute lung injury by inducing autophagic flux to facilitate STING degradation. This work provides a new paradigm for designing targeted nanotherapeutics to modulate STING activation in inflammatory diseases.