Increased plasma CXCL10 may be a marker of increased risk of immune restoration disease associated with nonviral pathogens

IP-10 and MIG are sensitive markers of early virological response to HIV-1 integrase inhibitors

Background

Interferon-inducible protein-10 (IP-10) and monokine induced by interferon-gamma (MIG) are chemokines recognized as inflammatory biomarkers during HIV-1 infection. We assessed their early and long-term dynamics after initiation of antiretroviral treatment (ART).

Methods

Persons with HIV-1 (PWH) aged>18 years starting their first ART in 2015-2021 in a prospective cohort (n=73) were included. IP-10 and MIG plasma levels were quantified using a multiplexed bead-based assay.

Results

IP-10 and MIG plasma levels showed a significant and consistent reduction following ART (80% integrase inhibitor [INSTI]-based) initiation, starting at day 20 and maintained throughout the study period (48 months), paralleling the HIV-1 RNA decay and CD4+ count recovery (p<0·001). At baseline, PWH≥ 50 years, CDC stage C and CD4+ count<350cells/mm3 had higher levels of IP-10 (p=0·022, p=0·001 and p=0·002, respectively) and MIG (p<0·001, p=0·024 and p=0·069, respectively). All of them matched their counterparts several months following ART initiation. MIG levels showed a greater decrease at day 10 in those treated with INSTI (p=0·038). Low-level HIV-1 viremia did not impact MIG or IP-10 levels.

Conclusion

Plasma IP-10 and MIG showed an early significant decline following ART initiation, with greater early declines in MIG levels in INSTI-based regimens. These findings suggest a strong impact of HIV-1 viremia on IP-10 and MIG levels.

PDGFR-alpha inhibits melanoma growth via CXCL10/IP-10: a multi-omics approach

Melanoma is the most aggressive skin-cancer, showing high mortality at advanced stages. Platelet Derived Growth Factor Receptor-alpha (PDGFR-alpha) potently inhibits melanoma- and endothelium-proliferation and its expression is significantly reduced in melanoma-biopsies, suggesting that melanoma progression eliminates cells expressing PDGFR-alpha. In the present study transient overexpression of PDGFR-alpha in endothelial (HUVEC) and melanoma (SKMel-28, A375, Preyer) human-cells shows strong anti-proliferative effects, with profound transcriptome and miRNome deregulation. PDGFR-alpha overexpression strongly affects expression of 82 genes in HUVEC (41 up-, 41 down-regulated), and 52 genes in SKMel-28 (43 up-, 9 down-regulated). CXCL10/IP-10 transcript showed up to 20 fold-increase, with similar changes detectable at the protein level. miRNA expression profiling in cells overexpressing PDGFR-alpha identified 14 miRNAs up- and 40 down-regulated, with miR-503 being the most down-regulated (6.4 fold-reduction). miR-503, miR-630 and miR-424 deregulation was confirmed by qRT-PCR. Interestingly, the most upregulated transcript (i.e., CXCL10/IP-10) was a validated miR-503 target and CXCL10/IP-10 neutralization significantly reverted the anti-proliferative action of PDGFR-alpha, and PDGFR-alpha inhibition by Dasatinb totally reverted the CXCL10/IP10 induction, further supporting a functional interplay of these factors. Finally, integration of transcriptomics and miRNomics data highlighted several pathways affected by PDGFR-alpha.

This study demonstrates for the first time that PDGFR-alpha strongly inhibits endothelial and melanoma cells proliferation in a CXCL10/IP-10 dependent way, via miR-503 down-regulation.

HIV-1 infection induces strong production of IP-10 through TLR7/9-dependent pathways

OBJECTIVE

To study the cytokine/chemokine profiles in response to HIV-1 viremia, and elucidate the pathways leading to HIV-1-induced inflammation.

DESIGN/METHODS

Plasma levels of 19 cytokines in individuals with early HIV-1 infection and individuals undergoing treatment interruptions were evaluated via multiplex assay. To investigate the cellular sources of relevant cytokines, sorted cells from HIV-1 infected individuals were assessed for mRNA expression. Relevant signaling pathways were assessed by comparing cytokine production patterns of peripheral blood mononuclear cells stimulated with intact HIV-1 or specific Toll-like receptor (TLR) stimulants with and without a TLR7/9 antagonist.

RESULTS

IP-10 plasma concentration was most significantly associated with HIV-1 viral load and was the most significant contributor in a multivariate model. IP-10 mRNA was highly expressed in monocytes and mDCs and these cells were the dominant producers after in-vitro stimulation with TLR7/8 ligands (CL097 and ssRNAGag1166), AT-2 HIV-1, and HIV-1NL43 virus. Partial least square discriminant analysis of culture supernatants revealed distinct cytokine/chemokine secretion profiles associated with intact viruses compared with TLR7/8 ligands alone, with IP-10 production linked to the former. A TLR7/9 antagonist blocked IP-10 production following whole virus stimulation, suggesting the involvement of TLR7/9 in the recognition of HIV-1 by these cells.

CONCLUSION

Monocytes and mDCs produce significant amounts of IP-10 in response to HIV-1 viremia and after in-vitro stimulation with HIV-1. Stimulation with HIV-1-derived TLR7/8-ligands versus HIV-1 resulted in distinct cytokine/chemokine profiles, indicating additional pathways other than TLR7/8 that lead to the activation of innate immune cells by HIV-1.