Methods for Delivering DNA to Intracellular Receptors

Area of Science:

• Immunology
• Molecular Biology
• Cell Biology

Background:

• Cytosolic DNA is a key indicator of infection, triggering crucial immune responses like type I interferon (IFN) production and AIM2 inflammasome activation.
• Studying these responses typically involves introducing DNA into macrophage cytosol via chemical transfection or electroporation, each with specific applications.
• Existing methods present challenges in efficiency and control over the induced immune signaling pathways.

Purpose of the Study:

• To optimize and refine existing methods for introducing DNA into the cytosol of macrophages.
• To enhance the speed and strength of cytosolic DNA-induced immune responses, specifically type I IFN and AIM2 inflammasome activation.
• To provide flexible protocols allowing for the isolated study of cytosolic DNA sensing or simultaneous stimulation of both cytosolic and endosomal receptors (TLR9).

Main Methods:

• Developed optimized protocols for both electroporation and chemical transfection of DNA into macrophages.
• Implemented a novel technique involving the centrifugation of chemical transfection reagents onto cells to improve efficiency.
• Utilized specific DNA choices to selectively target either cytosolic DNA sensing pathways or a combination of cytosolic and endosomal (TLR9) pathways.

Main Results:

• Optimized chemical transfection, particularly with reagent centrifugation, significantly increased the speed and strength of type I IFN and AIM2 inflammasome responses.
• Electroporation protocols were refined for efficient DNA delivery into the cytosol.
• Demonstrated the ability to selectively study cytosolic DNA responses or simultaneously activate both cytosolic DNA sensors and endosomal Toll-like Receptor 9 (TLR9).

Conclusions:

• Optimized electroporation and chemical transfection methods provide robust and efficient tools for studying innate immune responses to cytosolic DNA.
• These refined techniques allow for precise control over immune pathway activation, facilitating deeper understanding of infection sensing mechanisms.
• The developed protocols offer versatility for investigating isolated or combined innate immune signaling, advancing research in host defense and inflammatory diseases.