Biology subjects

DaCunza, J. T.

Publications and source records attributed to DaCunza, J. T..

2 recordsLinked to original sources

bioRxiv2026

Macrophage-derived extracellular vesicles promote T cell-dependent inflammatory pain resolution

Inflammatory pain resolution is increasingly recognized as an active, immune-regulated process, yet the adaptive immune mechanisms that govern this process remain poorly defined. We previously demonstrated that intrathecal administration of macrophage-derived small extracellular vesicles (sEVs) from unstimulated (sEV) or LPS-stimulated (sEV+) RAW 264.7 cells accelerate resolution of complete Freunds adjuvant (CFA)-induced inflammatory pain in male mice. However, the immunological mechanisms underlying this effect remain undefined. Given growing evidence that T cells regulate inflammatory pain resolution, we investigated whether macrophage-derived sEVs engage adaptive immune pathways to promote recovery. In vitro, both sEV and sEV+ enhanced T cell activation, with sEV+ exhibiting greater immunostimulatory capacity. Direct effects on T cells were modest; instead, sEV+ induced robust antigen-presenting cell (APC)-dependent T cell activation characterized by increased costimulatory molecule expression and enhanced Th1 polarization. Loss-of-function and rescue studies in Rag2-/- mice demonstrate that T cells are required for late-phase sEV+-mediated inflammatory pain resolution. In vivo, sEV+ elicited immunostimulatory responses in intrathecal-draining cervical and CFA-draining sacral/internal iliac lymph nodes. Together, these findings identify adaptive immune engagement as a critical mediator of sEV+-induced pain resolution and position macrophage-derived sEVs as a cell-free immunotherapeutic modality that harnesses endogenous T cell-dependent mechanisms of active inflammatory pain resolution. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=137 SRC="FIGDIR/small/706465v1_ufig1.gif" ALT="Figure 1"> View larger version (32K): org.highwire.dtl.DTLVardef@e49aa4org.highwire.dtl.DTLVardef@648c9forg.highwire.dtl.DTLVardef@14c3cc6org.highwire.dtl.DTLVardef@2a17f0_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2026

Microglial epigenetic memory is associated with accelerated resolution of inflammatory pain induced by prophylactic macrophage-derived small extracellular vesicles

Small extracellular vesicles (sEVs) including exosomes play an important role in intercellular communication and can exert immunomodulatory effects in recipient cells. We have shown that a single prophylactic intrathecal injection of sEVs from RAW 264.7 macrophages two weeks prior, promotes faster resolution of mechanical and thermal hypersensitivity in the complete Freunds adjuvant (CFA) mouse model of inflammatory pain. How this long-term memory develops, and how sEVs regulate immune responses are unknown. Recent studies have shown that priming microglia with inflammatory stimuli can enhance or suppress responses to a delayed secondary insult via epigenetic modifications. We hypothesized that prophylactic intrathecal administration of macrophage-derived sEVs confers accelerated resolution of inflammatory pain by reprogramming epigenetic memory in spinal microglia in recipient CFA model mice. To determine whether prophylactic sEVs could attenuate pain in the absence of microglia when administering sEVs, we ablated microglia using a colony-stimulating factor 1 receptor (CSF1R) inhibitor, PLX5622. sEV-induced pain prophylaxis was completely abolished in PLX5622-fed mice, indicating that microglia are required to be present during sEV administration to confer early resolution of inflammatory pain hypersensitivity. ChIP-seq analysis in spinal microglia 14 days after sEV administration (prior to CFA) revealed an increased number of gene loci enriched for H3K4me1, a hallmark of innate immune memory. Furthermore, inhibiting the H3K4 mono-methyltransferase SETD7 abolished sEV-induced pain attenuation. Our findings indicate that both microglia and its epigenetic reprogramming contribute to pain prophylaxis induced by macrophage-derived sEVs, providing novel insights into the development of non-addictive preventive analgesia.

neuroscience↗