Stimulation of HIV expression by intracellular calcium pump inhibition

Area of Science:

• Virology
• Cell Biology
• Immunology

Background:

• Latently infected T-lymphocytic cells harbor human immunodeficiency virus (HIV).
• Intracellular calcium sequestration plays a role in cellular processes.
• Understanding HIV latency and reactivation is crucial for developing effective therapies.

Purpose of the Study:

• To investigate the role of intracellular calcium sequestration in regulating HIV production.
• To determine if manipulating calcium stores affects HIV transcription in T-lymphocytes.
• To identify potential therapeutic targets for controlling HIV reactivation.

Main Methods:

• Inhibition of sarco-endoplasmic reticulum-type calcium transport ATPases using thapsigargin or cyclopiazonic acid.
• Fluorimetric measurement of thapsigargin-sensitive calcium pools in Indo-loaded cells.
• Assays for soluble viral core p24 production, viral antigen staining, and HIV long terminal repeat-directed reporter gene expression.
• Dose-dependent blockade of virus induction using the calcium channel blocker econazole.

Main Results:

• Inhibition of calcium transport ATPases induced HIV production in ACH-2 cells.
• Depletion of intracellular calcium pools significantly activated HIV production.
• Viral activation was confirmed by increased p24 production, viral antigen expression, and reporter gene activity.
• Econazole blocked HIV production in a dose-dependent manner.
• Thapsigargin did not significantly stimulate virus production in J1.1 cells.

Conclusions:

• Intracellular calcium pool function is involved in the cell type-specific control of proviral HIV transcription.
• ACH-2 cells serve as a valuable model for studying calcium-dependent activation of HIV transcription.
• Targeting intracellular calcium pathways may offer a novel strategy for managing HIV latency.