HSV ICP0 recruits USP7 to modulate TLR-mediated innate response

Area of Science:

• Immunology
• Virology
• Molecular Biology

Background:

• Pattern recognition receptors (PRRs) are crucial for innate immunity against pathogens.
• Herpes simplex virus (HSV) evades host defenses, leading to persistent infections.
• The mechanisms by which HSV interferes with host immune responses are not fully understood.

Purpose of the Study:

• To elucidate the mechanism by which HSV protein ICP0 inhibits Toll-like receptor (TLR)-dependent inflammatory responses.
• To investigate the role of USP7 (HAUSP) in regulating TLR signaling and its interaction with ICP0.

Main Methods:

• Investigated the interaction between HSV ICP0 and USP7.
• Utilized cell-based assays to examine the translocation of USP7 and its effect on TLR signaling pathways (NF-kappaB, JNK).
• Analyzed the deubiquitination of TRAF6 and IKKgamma by USP7 in response to TLR activation.

Main Results:

• HSV ICP0 promotes the translocation of USP7 from the nucleus to the cytoplasm upon TLR engagement.
• Cytoplasmic USP7 deubiquitinates TRAF6 and IKKgamma, terminating TLR-mediated NF-kappaB and JNK activation.
• ICP0 hijacks USP7's negative feedback role in TLR signaling to suppress innate immunity.

Conclusions:

• USP7 acts as a negative regulator of TLR signaling, terminating inflammatory responses.
• HSV ICP0 exploits the USP7-mediated negative feedback loop to attenuate innate immunity, facilitating viral persistence.
• Understanding this mechanism provides insights into HSV pathogenesis and potential therapeutic targets.