The macrophage-intrinsic MDA5/IRF5 axis drives HIV-1 intron-containing RNA-induced inflammatory responses
Sita Ramaswamy, … , Manish Sagar, Suryaram Gummuluru
Sita Ramaswamy, … , Manish Sagar, Suryaram Gummuluru
Published June 10, 2025
Citation Information: J Clin Invest. 2025;135(16):e187663. https://doi.org/10.1172/JCI187663.
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Research Article AIDS/HIV Aging Inflammation

The macrophage-intrinsic MDA5/IRF5 axis drives HIV-1 intron-containing RNA-induced inflammatory responses

Abstract

Despite effective antiretroviral therapy, transcriptionally competent HIV-1 reservoirs remain and contribute to persistent immune activation in people living with HIV (PWH). HIV-1–infected macrophages are important mediators of chronic innate immune activation, though the mechanisms remain unclear. We previously reported that nuclear export and cytoplasmic expression of HIV-1 intron-containing RNA (icRNA) activates mitochondrial antiviral signaling (MAVS) protein–mediated type I IFN responses in macrophages. In this study, we demonstrate an essential role of melanoma differentiation–associated protein 5 (MDA5) in sensing HIV-1 icRNA and promoting MAVS-dependent interferon regulatory factor 5 (IRF5) activation in macrophages. Suppression of MDA5 but not retinoic acid–inducible gene I expression nor disruption of the endosomal TLR pathway abrogated HIV-1 icRNA-induced type I IFN responses and IP-10 expression in macrophages. Furthermore, induction of IP-10 in macrophages upon HIV-1 icRNA sensing by MDA5 was dependent on IRF5. Additionally, monocytes and monocyte-derived macrophages (MDMs) from older (>50 years) individuals exhibited constitutively higher levels of IRF5 expression compared with younger (<35 years) individuals, and HIV-1 icRNA-induced IP-10 expression was significantly enhanced in older macrophages, which was attenuated upon ablation of IRF5 expression, suggesting that IRF5 functions as a major mediator of proinflammatory response downstream of MDA5-dependent HIV-1 icRNA sensing, dysregulation of which might contribute to chronic inflammation in older PWH.

Authors

Sita Ramaswamy, Hisashi Akiyama, Jacob Berrigan, Andrés A. Quiñones-Molina, Alex J. Olson, Yunhan Chen, YanMei Liang, Andrew J. Henderson, Archana Asundi, Manish Sagar, Suryaram Gummuluru

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Figure 8

MDMs isolated from older donors exhibit higher levels of HIV-1–induced immune activation.

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MDMs isolated from older donors exhibit higher levels of HIV-1–induced i...
(A) RNA isolated from LaiΔenvGFP/G-infected MDMs (MOI 2) was analyzed via Nanostring nCounter using the Myeloid Innate Immunity V2 panel. Baseline expression of the gene panel was calculated using nSolver and plotted as a ratio of old (HIV) versus young (HIV) with IRFs (red) highlighted. The dashed line represents a P value of 0.05. (B) Raw count values for IRF3, IRF5, and IRF7 were plotted to assess differences. (C and D) Fold changes in innate immune gene expression in HIV-infected MDMs with or without EFV were plotted. Data from MDMs from (C) older (>50 yo) and (D) younger (<35 yo) donors are shown. Differentially expressed ISGs (blue) and IRFs/IRF targets (red) are highlighted. The dashed line represents a P value of 0.05. (E and F) Supernatants were analyzed for (E) p24gag production and (F) IP-10 levels via ELISA. (G) IP-10 levels were normalized to those of p24gag for each donor. (H) MDMs were transfected with either control or IRF5 targeting siRNA prior to infection with LaiΔenvGFP/G. IP-10 and p24gag secretion was measured at 3 dpi. Data are represented as mean ± SEM, with each dot representing an individual donor (B and E–G) or with each dot representing a target gene (A, C, and D). Significance was assessed via unpaired 2-tailed t test (A, B, and E–G), paired 2-tailed t test (C and D), or 1-way ANOVA with Tukey’s multiple-comparison test (H). *P < 0.05.