The cGAS/STING Pathway Is Important for Dendritic Cell Activation but Is Not Essential to Induce Protective Immunity...

Area of Science:

• Immunology
• Microbiology
• Cellular Biology

Background:

• Mycobacterium tuberculosis (Mtb) infection is a significant global health issue.
• The STING (stimulator of interferon genes) pathway is vital for host cytosolic surveillance.
• Previous research on STING in Mtb infection primarily focused on macrophages, necessitating in vivo investigation.

Purpose of the Study:

• To investigate the role of STING in dendritic cell (DC) activation and the host immune response to Mtb infection in vivo.
• To determine the contribution of STING and cGAS (cyclic GMP-AMP synthase) to host defense against Mtb.

Main Methods:

• Analysis of STING involvement in DC activation markers (CD40, CD86), IFN-β, and IL-12 production upon Mtb infection.
• Assessment of STING and cGAS gene and protein expression in response to Mtb DNA.
• Evaluation of Mtb aerogenic infection in STING- and cGAS-deficient mice, monitoring body weight, bacterial load, survival, lung inflammation, cytokine production, and inflammatory cell recruitment.

Main Results:

• STING activation in DCs was essential for IFN-β and IL-12 production and CD40/CD86 expression.
• Mtb DNA induced STING activation in murine fibroblasts.
• In vivo, Mtb infection upregulated STING and cGAS, and pulmonary IFN-β expression relied on both.
• STING- or cGAS-deficient mice showed no significant differences in body weight, bacterial burden, survival, lung inflammation, or cytokine profiles compared to wild-type controls.

Conclusions:

• The STING pathway plays a critical role in Mtb-induced dendritic cell activation.
• Despite its importance in DC activation, the STING pathway is not essential for overall host protection against Mtb infection in vivo.