Biology subjects

Reddy, D.

Publications and source records attributed to Reddy, D..

7 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↗

bioRxiv2025

A small molecule inhibitor of NVL suppresses tumor growth by blocking ribosome biogenesis

A longstanding hypothesis, stemming from the enlarged nucleoli typical of cancer cells, posits ribosome production as a selective cancer liability. Certain genotoxic chemotherapies work partly by disrupting ribosome biogenesis, highlighting the need for selective inhibitors of this pathway. Using forward genetics, we identified mutations in the essential 60S ribosomal subunit assembly factor NVL that confer resistance to MM17, a dibenzothiazepinone with anticancer activity. Cryo-EM reconstructions of the NVL hexameric assembly reveal two MM17 docking sites adjacent to resistance mutations. NVL inhibition by MM17 arrests 60S biogenesis in the nucleolus and induces cell cycle arrest or apoptosis through both MDM2/p53-dependent and p53-independent pathways, without causing DNA damage. A bioavailable analog, MM927, suppresses tumor growth in mouse models of leukemia and colorectal cancer without observable toxicity. These findings establish NVL inhibitors as a promising new class of targeted therapeutics and validate ribosome biogenesis as a cancer-specific vulnerability.

biochemistry↗

bioRxiv2025

Neuroimaging Biomarkers of Neuroprotection: Impact of Voluntary versus Enforced Exercise in Alzheimers Disease Models

Exercise is a promising strategy for preventing or delaying Alzheimers disease (AD), yet its mechanisms remain unclear. We investigated how exercise influences brain structure, function, and behavior in a familial AD model. Mice underwent voluntary, voluntary plus enforced exercise, or remained sedentary. Neuroimaging included in vivo manganese-enhanced MRI (MEMRI). perfusion, and ex vivo diffusion MRI to assess morphometry, activity, cerebral blood flow (CBF), microstructural integrity and connectivity. Both exercise regimens induced structural and functional brain adaptations while reducing anhedonia. Voluntary exercise increased cortical and limbic volumes, particularly in the hippocampus, cingulate, and entorhinal cortex, supporting cognitive and emotional regulation. Adding enforced exercise influenced subcortical and sensory regions, including visual, motor and associative areas, supporting sensory-motor integration. MEMRI revealed increased activity in sensorimotor, limbic, and associative cortices, with voluntary exercise enhancing limbic and associative regions, and enforced exercise strengthening sensorimotor and subcortical circuits. White matter integrity improved in memory-associate pathways such as the corpus callosum, cingulum, and hippocampal commissure. Synaptic remodeling was observed in the cingulate cortex, anterior thalamic nuclei, and amygdala. Voluntary exercise enhanced CBF in the motor cortex and hippocampus, while enforced exercise limited these increases. Connectivity analyses revealed exercise-responsive networks spanning the cingulate cortex, entorhinal cortex, anterior thalamic nuclei, and basolateral amygdala, and associated tracts. Graph analyses linked running distance with increased thalamic, brainstem, and cerebellar connectivity, associating exercise intensity with plasticity. These findings highlight the ability of chronic exercise to modulate neuroimaging biomarkers through distinct but complementary pathways, reinforcing its potential as a neuroprotective intervention for AD. HighlightsO_LIExercise alters MRI biomarkers via distinct and partially overlapping mechanisms. C_LIO_LIVoluntary exercise boosts cortical and limbic regions for emotion and cognition. C_LIO_LIEnforced exercise strengthens subcortical and sensory areas for motor control. C_LIO_LIFA increases suggest memory tract reinforcement and grey matter remodelling. C_LIO_LIGraph analysis reveals plasticity in memory, emotion, and reward circuits. C_LI

neuroscience↗

bioRxiv2024

Morphine-induced hyperalgesia impacts small extracellular vesicle miRNA composition and function

Morphine and other synthetic opioids are widely prescribed to treat pain. Prolonged morphine exposure can paradoxically enhance pain sensitivity in humans and nociceptive behavior in rodents. To better understand the molecular mechanisms underlying opioid-induced hyperalgesia, we investigated changes in miRNA composition of small extracellular vesicles (sEVs) from the serum of mice after a morphine treatment paradigm that induces hyperalgesia. We observed significant differential expression of 18 miRNAs in sEVs from morphine-treated mice of both sexes compared to controls. Several of these miRNAs were bioinformatically predicted to regulate cyclic AMP response element binding protein (CREB), a well-characterized transcription factor implicated in pain and drug addiction. We confirmed the binding and repression of Creb mRNA by miR-155 and miR-10a. We tested if serum-derived sEVs from morphine-treated mice could elicit nociceptive behavior in naive recipient mice. Intrathecal injection of 1 g sEVs did not significantly impact basal mechanical and thermal threshold in naive recipient mice. However, prophylactic 1 g sEV administration in recipient mice resulted in faster resolution of complete Freunds adjuvant-induced mechanical and thermal inflammatory hypersensitivity. Other behaviors assayed following administration of these sEVs were not impacted including sEV conditioned place preference and locomotor sensitization. These results indicate that morphine regulation of serum sEV composition can contribute to analgesia and suggest a potential for sEVs to be a non-opioid therapeutic intervention strategy to treat pain.

neuroscience↗

bioRxiv2024

Inflammatory pain resolution by mouse serum-derived small extracellular vesicles

Chronic pain is a significant public health issue. Current treatments have limited efficacy and significant side effects, warranting research on alternative strategies for pain management. One approach involves using small extracellular vesicles (sEVs) to transport beneficial biomolecular cargo to aid pain resolution. Exosomes are 30-150 nm sEVs that can carry RNAs, proteins, and lipid mediators to recipient cells via circulation. Exosomes can be beneficial or harmful depending on their source and contents. To investigate the short and long-term effects of mouse serum-derived sEVs in pain modulation, sEVs from naive control or spared nerve injury (SNI) model donor mice were injected intrathecally into naive recipient mice. Basal mechanical thresholds transiently increased in recipient mice. This effect was mediated by opioid signaling as this outcome was blocked by naltrexone. Mass Spectrometry of sEVs detected endogenous opioid peptide leu-enkephalin. A single prophylactic intrathecal injection of sEVs two weeks prior to induction of the pain model in recipient mice delayed mechanical allodynia in SNI model mice and accelerated recovery from inflammatory pain after complete Freunds adjuvant (CFA) injection. ChipCytometry of spinal cord and dorsal root ganglion (DRG) from sEV treated mice showed that prophylactic sEV treatment reduced the number of natural killer (NK) and NKT cells in spinal cord and increased CD206+ anti-inflammatory macrophages in (DRG) after CFA injection. Further characterization of sEVs showed the presence of immune markers suggesting that sEVs can exert immunomodulatory effects in recipient mice to promote the resolution of inflammatory pain. Collectively, these studies demonstrate multiple mechanisms by which sEVs can attenuate pain.

neuroscience↗

bioRxiv2021

Structural basis of the interaction between SETD2 methyltransferase and hnRNP L paralogs for governing co-transcriptional splicing

The RNA recognition motif (RRM) binds to nucleic acids as well as proteins. More than one such domain is found in the pre-mRNA processing hnRNP proteins. While the mode of RNA recognition by RRMs is known, the molecular basis of their protein interaction remains obscure. Here we describe the mode of interaction between hnRNP L and LL with the methyltransferase SETD2. We demonstrate that for the interaction to occur, a leucine pair within a highly conserved stretch of SETD2 insert their side chains in hydrophobic pockets formed by hnRNP L RRM2. Notably, the structure also highlights that RRM2 can form a ternary complex with SETD2 and RNA. Remarkably, mutating the leucine pair in SETD2 also results in its reduced interaction with other hnRNPs. Importantly, the similarity that the mode of SETD2-hnRNP L interaction shares with other related protein-protein interactions reveals a conserved design by which splicing regulators interact with one another.

biochemistry↗

bioRxiv2020

DNA methylation mediated downregulation of histone H3 variant H3.3 affects cell proliferation contributing to the development of HCC

H3.3 variant is a versatile histone important for development and disease. We report a DNA methylation dependent decrease of histone H3 variant H3.3 in hepatocellular carcinoma (HCC) development and an increase in the level of the H3.2 variant. The loss of H3.3 correlates with a decrease in the histone PTMs associated with active transcription. The overexpression of H3.3 and H3.2 did not affect global PTMs and cell physiology, probably owing to the deregulation of specific histone chaperones CAF-1 (for H3.2) and HIRA (for H3.3) that we observed in HCC. Notably, upon P150 (CAF-1 subunit) knockdown in HCC cell lines, a cell cycle arrest in S-phase was observed, possibly due to the decrease in the histone levels necessary for DNA packaging. Furthermore, H3.3 knockdown in a preneoplastic liver cell line led to an increase in cell proliferation and a decreased transcription of tumor suppressor genes, recapitulating the tumor cell phenotype. Importantly, our data suggest that the use of DNA Methyl Transferase (DNMT) and Histone Deacetylase (HDAC) inhibitors to restore the expression of H3.3 and the altered chromatin state for the better clinical management of the disease.

cancer biology↗