Related Experiment Videos
[Molecular pathogenesis in tuberculosis complicated with AIDS].
Koh Nakata1, Yoshihiko Hoshino, Yoshihiro Honda
1Bioscience Medical Research Center, Niigata Medical Dental Hospital, Niigata, Japan. knak@med.niigata-u.ac.jp
Kekkaku : [Tuberculosis]
|February 26, 2005
Summary
Tuberculosis coinfection accelerates HIV-1 progression by increasing viral load. Macrophage interaction with lymphocytes reduces inhibitory C/EBP beta, enhancing HIV-1 replication via LTR derepression.
Area of Science:
- Immunology
- Virology
- Molecular Biology
Context:
- Tuberculosis (TB) is a major global epidemic, frequently co-occurring with Human Immunodeficiency Virus type 1 (HIV-1) infection.
- Coinfection with Mycobacterium tuberculosis (M. tuberculosis) is increasingly linked to accelerated Acquired Immunodeficiency Syndrome (AIDS) progression.
- In pulmonary TB, increased HIV-1 load and mutation are observed in affected lung segments.
Purpose:
- To investigate the molecular mechanisms by which M. tuberculosis coinfection influences HIV-1 replication in macrophages.
- To elucidate the role of C/EBP beta and lymphocyte-macrophage interactions in regulating HIV-1 transcription during coinfection.
Summary:
- M. tuberculosis differentially affects HIV-1 replication: stimulating it in some macrophage models via 5' LTR enhancement, but suppressing it in others.
- HIV-1 replication is repressed in differentiated THP-1 cells by M. tuberculosis, mediated by the 16kDa inhibitory form of C/EBP beta.
- Contact between activated lymphocytes and macrophages downregulates inhibitory C/EBP beta, leading to HIV-1 LTR derepression and enhanced viral replication, further boosted by soluble lymphocyte factors activating NF-kappaB.
Impact:
- Identifies the 16kDa isoform of C/EBP as a key regulator of HIV-1 replication in macrophages.
- Proposes derepression of HIV-1 LTR-mediated transcription as a mechanism for enhanced HIV-1 replication in pulmonary TB.
- Demonstrates that maximal HIV-1 LTR stimulation requires coordinated interaction between lymphocytes and macrophages, involving both cell contact and soluble factors.