Investigation of HIV-1 pathogenesis using humanized mouse model

Area of Science:

• Virology
• Immunology
• Pathogenesis

Background:

• Human immunodeficiency virus type 1 (HIV-1), the cause of AIDS, is a human-specific virus, making in vivo studies challenging.
• Existing research on HIV-1 accessory genes (Vif, Vpu, Vpr, Nef) in viral replication and pathogenesis in vivo is limited due to the lack of adequate animal models.

Purpose of the Study:

• To establish and utilize a humanized mouse model to investigate HIV-1 pathogenesis in vivo.
• To elucidate the roles of HIV-1 accessory proteins in viral replication, infection, and pathogenesis within a physiological context.

Main Methods:

• Development of a human hematopoietic stem cell-transplanted "humanized" mouse model capable of maintaining human hematopoiesis.
• Infection of humanized mice with HIV-1 and analysis of pathogenesis, including CD4-positive T cell decline and immune activation.
• Utilizing a series of mutated HIV-1 strains to assess the function of accessory proteins in vivo.

Main Results:

• The humanized mouse model successfully reproduced key aspects of HIV-1 pathogenesis, such as the decline of peripheral CD4-positive T cells and immune activation.
• HIV-1 accessory proteins were found to significantly promote viral replication in vivo.
• Accessory proteins function by antagonizing/degrading antiviral cellular proteins or exploiting a specific subset of human CD4-positive T cells.

Conclusions:

• The humanized mouse model is a valuable tool for studying HIV-1 infection dynamics and pathogenesis in vivo.
• HIV-1 accessory proteins play a critical role in enhancing viral replication and disease progression within the humanized host.
• Understanding the mechanisms of accessory protein function provides insights into potential therapeutic targets for HIV-1 infection.