Matt, S. M. | bioRxiv Science

bioRxiv2026

It's Not Rewarding for Mitochondria: Dopamine-Induced Mitochondrial Dysfunction Activates cGAS-STING to Drive IL-6 Secretion in Macrophages

Despite increasing data demonstrating dopamine as an inflammatory mediator of the innate immune system, the molecular mechanisms underlying its effects in human cells remain incompletely defined. Here, we define an unrecognized pathway in which dopamine induces robust IL-6 secretion in primary human monocyte-derived macrophages (hMDMs) through mitochondrial stress. Dopamine initiates a transient mitochondrial membrane depolarization that leads to sustained alterations in mitochondrial dynamics, including morphology and metabolism, in a time-dependent manner. These events promote the mtDNA release into the cytoplasm, triggering cGAS-STING pathway and downstream NF-{kappa}B signaling. Pharmacological inhibition at multiple nodes of this pathway attenuates IL-6 secretion, establishing mitochondrial dysfunction and cGAS-STING signaling as central mediators of dopamine-driven IL6 secretion. Variability in dopamine receptor expression across donors correlates with the magnitude of IL-6 responses. Together, these findings redefine the interface between dopamine signaling and systemic inflammation and highlight an unrecognized source of inter-individual variation in immune responses. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=171 SRC="FIGDIR/small/719926v1_ufig1.gif" ALT="Figure 1"> View larger version (47K): org.highwire.dtl.DTLVardef@e2c133org.highwire.dtl.DTLVardef@fa0a15org.highwire.dtl.DTLVardef@1ac1f91org.highwire.dtl.DTLVardef@14c8c53_HPS_FORMAT_FIGEXP M_FIG C_FIG Dopamine induces mitochondrial dysfunction mediated through dopamine receptors signaling. This includes alterations in mitochondrial membrane potential, leading to excessive DRP1-mediated mitochondrial fission, increased production of mitochondrial superoxide, and metabolic reprogramming toward enhanced glycolysis with reduced oxidative phosphorylation. Sustained mitochondrial damage is further exacerbated by impaired mitophagy, resulting in the release of mitochondrial DNA (mtDNA) into the cytoplasm. Cytosolic mtDNA, acting as a double-stranded DNA ligand, activates the cGAS-STING pathway, which subsequently induces NF-{kappa}B signaling, ultimately driving the production and secretion of the pro-inflammatory cytokine IL-6. Created on Biorender.com.

immunology↗

bioRxiv2025

High-throughput High Content Quantification of HIV-1 Viral Infectious Output

Infection with human immunodeficiency virus (HIV-1) remains a global health issue and still drives the development of significant pathology and various comorbidities. Antiretroviral therapy (ART) can effectively suppress viral replication but is often initiated months or years after initial infection, leaving a substantial period in which viral replication progresses unchecked. While ART suppresses HIV-1 replication, it does not prohibit the development of HIV-1-associated comorbidities, highlighting a lack of understanding in the connection between replication and HIV-1-associated pathogeneses. Thus, it is critical to better define HIV-1 replication dynamics to more effectively target different stages of the viral replication cycle in distinct cell populations. Here, we show a high-content imaging reporter assay that uses modified human osteosarcoma cells expressing HIV-1 receptors (GHOST cells) which fluoresce in response to HIV-1 infection. These cells have been previously used to assess HIV-1 infectivity and tropism, but this modified assay enables rapid evaluation of large numbers of samples with consistency and replicability, while also easily integrating into existing experimental pipelines that analyze p24 secretion in collected supernatants. This also allows for direct correlation between infectivity and p24 secretion, resulting in a deeper interrogation and more robust understanding of HIV-1 infection kinetics. Institutional PermissionsAll of the primary cells used in this study were obtained from donors in accordance with Institutional Review Board protocols at the New York Blood Center and Drexel University. All studies using primary cells were performed with cells from deidentified donors and were found by the Institutional Review Board at Drexel University to be exempt from human subjects protocols (protocol number 2208009386). All experiments using in vitro cell lines or primary human cells were approved by the Institutional Biosafety Committee and at Drexel University. HighlightsO_LIThe current toolkit for evaluating in vitro HIV-1 infection dynamics does not currently include an assay providing direct, efficient assessments of infectivity in large numbers of samples. C_LIO_LIDirect assessment of viral infectivity longitudinally alongside other measurements of viral infection such as p24 secretion or amount of proviral DNA enables correlation of different stages of viral replication efficiency over time. C_LIO_LIThe high-content viral titer assay described here correlates with widely used surrogate measures of viral infectivity, such as p24 secretion, and integrates easily into existing experimental pipelines that collect supernatant from infected cultures. C_LIO_LIAdapting fluorescent reporter assays to a high-content imaging and analysis pipeline creates a high-throughput assay of direct infectivity that enables evaluation of changes in infectivity across multiple treatments or timepoints and integrates easily into existing experimental pipelines that collect supernatant from infected cultures. C_LI

microbiology↗