# CXCL9 and CXCL10 Induce Expression of Nociceptive Ion Channels in Primary Sensory Neurons in Models of HIV-Associated Distal Sensory Polyneuropathy

## TL;DR

This study shows that CXCL9 and CXCL10 increase pain-related ion channels in nerve cells, contributing to HIV-related nerve damage even with treatment.

## Contribution

The study identifies a novel role for CXCL9 and CXCL10 in driving TRPV1 expression in sensory neurons during HIV-DSP.

## Key findings

- CXCL9 and CXCL10 significantly increased TRPV1 expression in iPSC-derived sensory neurons.
- IFNγ stimulated macrophages to release CXCL9 and CXCL10, which partially contributed to TRPV1 upregulation.
- CXCL9/10 signaling persists in ART-treated SIV-infected models, suggesting a role in HIV-DSP pathogenesis.

## Abstract

HIV-associated distal sensory polyneuropathy (HIV-DSP) remains prevalent even in the antiretroviral therapy (ART) era. Previously, we identified the upregulation of nociceptive ion channels transient receptor potential vanilloid 1 (TRPV1) and ankyrin 1 (TRPA1) in the dorsal root ganglia (DRG) of simian immunodeficiency virus (SIV)-infected ART-treated macaques. To investigate upstream mechanisms, we performed bulk RNA-seq and pathway analysis on DRGs from uninfected, SIV-infected, and SIV-infected/ART macaques. SIV infection drove strong activation of upstream regulators of interferon γ (IFNγ) and lipopolysaccharide (LPS). Although ART reduced overall IFNγ and LPS pathway activity, the IFNγ-inducible chemokines C-X-C motif chemokine ligand (CXCL)9 and CXCL10 remained significantly upregulated. To determine whether these chemokines influence TRPV1/TRPA1 expression, we treated induced pluripotent stem cell-derived peripheral sensory neurons (iPSC-PSNs) with CXCL9 and CXCL10, which induced a significant increase in TRPV1 but not TRPA1 expression. In parallel experiments, IFNγ but not LPS stimulated monocyte-derived macrophages (MDMs) to release CXCL9 and CXCL10. Conditioned media from IFNγ-treated MDMs modestly increased TRPV1 expression in iPSC-PSNs, and pharmacological inhibition of CXCR3, the receptor of CXCL9/10, did not reduce this effect. Together, these data indicate that persistent IFNγ-driven CXCL9/10 signaling may be one contributor to nociceptor sensitization underlying HIV-DSP, even in the presence of ART.