Biology subjects

Plumb, A. N.

Publications and source records attributed to Plumb, A. N..

7 recordsLinked to original sources

bioRxiv2026

Antibiotics modulate activity of mouse and human dorsal root ganglia neurons

Antibiotics are among the most prescribed medications worldwide, yet their direct effects on eukaryotic tissues remain largely unexplored. Here, we used in vitro calcium imaging to determine if clinically relevant concentrations of common antibiotics alter mouse and human dorsal root ganglion (DRG) neuron activity. We found that {beta}-lactams, macrolides, and tetracyclines induce calcium flux in sensory neurons within minutes of application. Regardless of antibiotic class, neuronal responses depend on extracellular calcium entry. Pharmacological manipulations further revealed that cephalexin responses depend on TRPA1 activity whereas doxycycline responses require mitochondrial reactive oxygen species (ROS) production. These findings demonstrate that clinically relevant concentrations of antibiotics directly modulate sensory neuron activity through divergent mechanisms, thus expanding our current understanding of antibiotic side effects.

neuroscience↗

bioRxiv2026

Adipose-driven complement-lipid reprogramming controls nociceptive vulnerability in obesity-associated osteoarthritis

Obesity amplifies osteoarthritis (OA) pain disproportionately to joint damage, creating a major unmet clinical need for non-opioid interventions that act beyond the joint. Using OA as a translational model, we integrated serum multi-omics in obese mice with surgically induced OA and genetic and adipose-reconstitution models of complement factor D (FD). In humans, we analyzed longitudinal metabolomics data from the IDEA weight-loss trial and conducted functional studies in dorsal root ganglion (DRG) neurons. Adipose-derived FD emerged as a regulator of systemic immunometabolic state: FD deficiency in obese mice worsened pain sensitivity whereas restoring circulating FD normalized pain and inflammatory markers without altering joint structure. Cross-species lipid profiling identified conserved shifts in linoleic acid versus arachidonic acid-derived lipids that were associated with pain phenotypes in mice and with pain improvement in humans. Defined lipid cocktails modulated excitability and TRPV1 sensitivity in human DRG neurons, and transcriptomics of knee-innervating DRGs revealed diet and FD-dependent activation of complement and neuronal excitability pathways. Together, these findings define an adipose-complement-lipid axis that regulates nociceptive vulnerability independent of joint damage and identify extra-articular targets for translational, non-opioid OA pain therapies. One Sentence SummaryWe identify an adipose-complement-lipid axis that systemically regulates sensory neuron sensitization, providing a mechanistic basis for pain-structure discordance in obesity-associated osteoarthritis.

physiology↗

bioRxiv2025

Life-long hydroxyurea treatment decreases chronic sickle cell disease pain

Chronic sickle cell disease (SCD) pain mechanisms remain critically understudied, even though more than 50% of patients develop this symptom as their disease progresses. Despite high face validity, there are critical gaps in transgenic SCD mouse model characterization and implementation that must be addressed in order to increase the translational relevance of these animals. First, it is unclear when the chronic pain phenotype first develops in these mice. Second, there are no studies that have measured chronic pain in animals following standard-of-care drug regimens. Herein, we address both of these gaps by performing reflexive pain behavior tests in hydroxyurea-treated Townes HbSS and HbAA mice from postnatal day 10 to 6 months of age. Hydroxyurea (HU), a compound that increases circulating levels of fetal hemoglobin (HbF), is a life-long therapy prescribed to individuals with SCD beginning as early as age 9 months. Here, we demonstrate that chronic mechanical hypersensitivity develops in Townes HbSS mice between P21-P28, a time frame that follows the HbF-to-HbS switch. When initiated at birth, HU treatment limits the extent of chronic mechanical pain development in HbSS mice. HU analgesic effects can be attributed to decreased innate immune tone in the periphery; life-long HU treatment decreases circulating monocyte counts in HbSS mice and reverses sensitization of TRPA1, a lipopolysaccharide receptor, in HbSS nociceptors. In conclusion, these studies provide additional support for early implementation of HU in SCD disease management, and furthermore, identify the LPS-TRPA1 signaling axis as a novel analgesic target for chronic SCD pain.

physiology↗

bioRxiv2025

Male-specific analgesic effects of minocycline in sickle cell disease are mediated by microglia and the microbiome

Over 50% of individuals with sickle cell disease (SCD) experience chronic pain that is phenotypically distinct from their acute, vaso-occlusive crisis pain. Chronic SCD pain is commonly managed with opioid-based drugs that are associated with unwanted side effects, incomplete pain relief, and - in this population - accessibility issues. Thus, new treatments for chronic SCD pain are desperately needed. Here, we examined the analgesic efficacy of acute minocycline treatment in transgenic SCD mice. SCD mice exhibit gut dysbiosis and chronic inflammation. Therefore, we hypothesized that minocycline would provide robust analgesia in this model given the drugs antibiotic and anti-inflammatory properties respectively. Six days of minocycline treatment reversed chronic mechanical hypersensitivity only in male SCD mice. We identified two potential mechanisms underlying these sex-specific effects. First, we observed increased microgliosis only in the dorsal horn of male SCD mice. Minocycline treatment had opposite effects on microglial number in male and female SCD spinal cords. Second, minocycline treatment altered the gut microbiota in a sex-specific fashion; fecal microbiota transplant (FMT) from minocycline-treated female SCD mice induced widespread pain in recipients whereas FMT from minocycline-treated male SCD mice did not. In summary, these experiments highlight novel sex-specific mechanisms of minocycline analgesia and support future exploration of minocycline use for SCD pain management, but only in male patients.

neuroscience↗

bioRxiv2023

Brain-derived neurotrophic factor contributes to activity-induced muscle pain in male but not female mice

Activity-induced muscle pain increases release of interleukin-1{beta} (IL-1{beta}) in muscle macrophages and the development of pain is prevented by blockade of IL-1{beta}. Brain derived neurotrophic factor (BDNF) is released from sensory neurons in response to IL-1{beta} and mediates both inflammatory and neuropathic pain. Thus, we hypothesized that metabolites released during fatiguing muscle contractions activate macrophages to release IL-1{beta}, which subsequently activate sensory neurons to secrete BDNF. To test this hypothesis, we used an animal model of activity-induced pain induced by repeated intramuscular acidic saline injections combined with fatiguing muscle contractions. Intrathecal or intramuscular injection of inhibitors of BDNF-Tropomyosin receptor kinase B (TrkB) signaling, ANA-12 or TrkB-Fc, reduced the decrease in muscle withdrawal thresholds in male, but not in female, mice when given before or 24hr after, but not 1 week after induction of the model. BDNF messenger ribonucleic acid (mRNA) was significantly increased in L4-L6 dorsal root ganglion (DRG), but not the spinal dorsal horn or gastrocnemius muscle, 24hr after induction of the model in either male or female mice. No changes in TrkB mRNA or p75 neurotrophin receptor mRNA were observed. BDNF protein expression via immunohistochemistry was significantly increased in L4-L6 spinal dorsal horn and retrogradely labelled muscle afferent DRG neurons, at 24hr after induction of the model in both sexes. In cultured DRG, fatigue metabolites combined with IL-1{beta} significantly increased BDNF expression in both sexes. In summary, fatigue metabolites release, combined with IL-1{beta}, BDNF from primary DRG neurons and contribute to activity-induced muscle pain only in males, while there were no sex differences in the changes in expression observed in BDNF.

neuroscience↗

bioRxiv2022

The impact of sex and physical activity on the local immune response to muscle pain

Induction of muscle pain triggers a local immune response to produce pain and this mechanism may be sex and activity level dependent. The purpose of this study was to measure the immune system response in the muscle following induction of pain in sedentary and physically active mice. Muscle pain was produced via an activity-induced pain model using acidic saline combined with fatiguing muscle contractions. Prior to induction of muscle pain, mice (C57/BL6) were sedentary or physically active (24hr access to running wheel) for 8 weeks. The ipsilateral gastrocnemius was harvested 24hr after induction of muscle pain for RNA sequencing or flow cytometry. RNA sequencing revealed activation of several immune pathways in both sexes after induction of muscle pain, and these pathways were attenuated in physically active females. Uniquely in females, the antigen processing and presentation pathway with MHC II signaling was activated after induction of muscle pain; activation of this pathway was blocked by physical activity. Blockade of MHC II attenuated development of muscle hyperalgesia exclusively in females. Induction of muscle pain increased the number of macrophages and T-cells in the muscle in both sexes, measured by flow cytometry. In both sexes, the phenotype of macrophages shifted toward a pro-inflammatory state after induction of muscle pain in sedentary mice (M1+M1/2) but toward an anti-inflammatory state in physically active mice (M2+M0). Thus, induction of muscle pain activates the immune system with sex-specific differences in the transcriptome while physical activity attenuates immune response in females and alters macrophage phenotype in both sexes.

immunology↗

bioRxiv2022

Selective Androgen Receptor Modulator Microparticle Formulation Reverses Muscle Hyperalgesia in Mouse Model of Widespread Muscle Pain

Currently, there is a need for the generation of non-opioid analgesics for treating chronic pain. Preclinical and clinical studies demonstrate the analgesic effects of testosterone. However, treatment with testosterone is not feasible due to adverse effects. Selective androgen receptor modulators (SARMs) were developed to overcome these limitations by minimizing activation of androgenic side effects. First, we demonstrate SARM administration alleviates widespread muscle pain in male and female mice. We then developed a SARM-loaded PLGA microparticle formulation that reverses widespread muscle pain in two injections. In vitro and in vivo release kinetics demonstrate the microparticle formulation had sustained SARM release for 4 weeks. Antagonism of androgen receptors blocked the analgesic effects of the SARM microparticles. SARM treatment had no effect on cardiac or liver enzymes, cardiac histology, and did not produce rewarding behavior. These studies demonstrate SARM microparticles as a potential therapeutic for chronic muscle pain. One Sentence SummaryA selective androgen receptor modulator microparticle formulation alleviates widespread muscle pain in male and female mice while being non-toxic.

neuroscience↗