Biology subjects

Adamczyk, N. S.

Publications and source records attributed to Adamczyk, N. S..

5 recordsLinked to original sources

bioRxiv2025

CD14 plays a critical role in pain and inflammation across multiple models of post-traumatic osteoarthritis

Inflammation is a primary driver of osteoarthritis (OA), and no therapies exist to halt or delay disease progression or substantially ameliorate the chronic pain, inflammation and disability that are characteristic of disease. Soluble CD14 (sCD14), a co-factor that enhances inflammatory toll-like receptor signaling, is present in synovial fluid in patients with OA and positively associates with joint space narrowing, synovial macrophage content, and pain. In this study, we show that increased sCD14 within human synovial fluid correlates with joint effusion volume and increased knee hyperalgesia. Next, we evaluated CD14 as a potential therapeutic target in three pre-clinical models of post traumatic OA (PTOA), using both genetic deficiency and pharmacologic blockade to modulate its activity. We demonstrate that deficiency or blockade of CD14 results in significant protection from increased evoked pain behaviors and from OA driven mobility impairments (i.e. decreased cage activity) across models that differ in severity, and across male and female cohorts. Using flow cytometry, single cell transcriptomics, and spatial proteomics, we further show that CD14-deficiency drastically influences the local synovial inflammatory landscape post-injury, reducing monocyte and macrophage populations and modulating local fibroblast populations. Targeting CD14 via genetic deficiency or therapeutic blockade revealed no substantial protection, but no worsening, of cartilage degeneration. Ultimately, our results provide strong support that targeting synovial inflammation through blockade of CD14 can safely ameliorate OA pain and disability after a pre-disposing injury. One Sentence SummaryThe study demonstrates the key role of CD14 in pain, mobility loss, and inflammation in PTOA, and demonstrates the therapeutic potential of CD14 blockade for OA pain relief.

immunology↗

bioRxiv2025

CXCL16 mediates nociception and inflammation in murine post-traumatic osteoarthritis

This study investigates the role of the chemokine CXCL16 and its receptor, CXCR6, in post-traumatic osteoarthritis (PTOA) and joint nociception, highlighting the potential of targeting the CXCL16-CXCR6 axis for therapeutically managing joint inflammation and pain. Following joint injury in mice, the CXCL16-CXCR6 signaling axis is activated in synovium, driven by synovial fibroblasts and macrophages. Human OA synovium also exhibited increased CXCL16 and CXCR6 gene expression. CXCL16 stimulated a pro-inflammatory response in fibroblasts and macrophages, contrasting with an anti-inflammatory response observed in mesenchymal progenitor cells. In mice, repeated intra-articular CXCL16 injections induced histological synovitis and sex-dependent activation of inflammatory and fibrotic transcriptional programs in synovium. Repeated CXCL16 joint injections also induced knee hyperalgesia, which was mitigated by co-administration of the CXCR6 antagonist, ML339. A single intra-articular injection of CXCL16 induced acute knee hyperalgesia as early as 30 minutes post-injection, which was completely abrogated by ML339 co-treatment, suggesting direct CXCL16 binding to nociceptor-expressed CXCR6. In a murine PTOA model, systemic CXCR6 antagonism with ML339 alleviated knee hyperalgesia and altered circulating immune cell profiles. Direct stimulation of mouse dorsal root ganglion-derived nociceptive neurons with CXCL16 induced rapid calcium signaling, which was abolished by co-treatment with ML339. These findings establish CXCL16 as a regulator of joint inflammation and identifies the CXCL16-CXCR6 binding mechanism as key in mediating pain-related behaviors and nociceptor activation, offering a therapeutic target for PTOA-related inflammation and pain management. One Sentence SummaryCXCL16 regulates synovial inflammation and mediates joint nociception via CXCR6, highlighting its potential as a therapeutic target for post-traumatic osteoarthritis.

physiology↗

bioRxiv2025

FM-dye inhibition of Piezo2 relieves acute inflammatory and osteoarthritis knee pain in mice of both sexes

Musculoskeletal pain is a significant burden affecting billions of people with little progress in the development of pharmaceutical pain relief options. The mechanically-activated ion channel Piezo2 has been shown to play a role in mechanical sensitization; however there has been little progress in examining therapeutics that target this molecule. The goal of this study was to assess the effect of two FM-dyes, FM1-43 or FM4-64, in reducing acute inflammatory and osteoarthritis knee joint pain in mice of both sexes. In our acute model of Complete Freunds adjuvant (CFA)-induced joint pain, mice intra-articularly injected with FM1-43 exhibited an attenuation of knee hyperalgesia 90 minutes following injection. In vivo calcium imaging of the dorsal root ganglion (DRG) also demonstrated a reduction in nociceptor responses to mechanical forces applied to the knee joint of CFA mice following FM-dye injection. Male and female WT mice subjected to partial medial meniscectomy (PMX) surgery as a model of osteoarthritis developed more severe knee hyperalgesia than nociceptor-specific Piezo2 conditional knock-out mice. Intra-articular injection of FM1-43 reduced both knee hyperalgesia and weight-bearing asymmetry in this model and had no effect in Piezo2 conditional knock-out mice. Finally, in mice with spontaneous osteoarthritis associated with aging, intra-articular injection of FM-dyes also reduced knee hyperalgesia. In conclusion, inhibiting Piezo2 genetically or pharmacologically was effective in reducing pain-related behaviors in mice of both sexes in the setting of inflammatory and osteoarthritis knee pain. These studies provide evidence of the therapeutic potential of targeting Piezo2 in musculoskeletal pain conditions.

neuroscience↗

bioRxiv2024

Acute systemic macrophage depletion in osteoarthritic mice alleviates pain-related behaviors and does not affect joint damage

BackgroundOsteoarthritis (OA) is a painful degenerative joint disease and a leading source of years lived with disability globally due to inadequate treatment options. Neuroimmune interactions reportedly contribute to OA pain pathogenesis. Notably, in rodents, macrophages in the DRG are associated with onset of persistent OA pain. Our objective was to determine the effects of acute systemic macrophage depletion on pain-related behaviors and joint damage using surgical mouse models in both sexes. MethodsWe depleted CSF1R+ macrophages by treating male macrophage Fas-induced apoptosis (MaFIA) transgenic mice 8-or 16-weeks post destabilization of the medial meniscus (DMM) with AP20187 or vehicle control (10 mg/kg i.p., 1x/day for 5 days), or treating female MaFIA mice 12 weeks post partial meniscectomy (PMX) with AP20187 or vehicle control. We measured pain-related behaviors 1-3 days before and after depletion, and, 3-4 days after the last injection we examined joint histopathology and performed flow cytometry of the dorsal root ganglia (DRGs). In a separate cohort of male 8-week DMM mice or age-matched naive vehicle controls, we conducted DRG bulk RNA-sequencing analyses after the 5-day vehicle or AP20187 treatment. ResultsEight-and 16-weeks post DMM in male mice, AP20187-induced macrophage depletion resulted in attenuated mechanical allodynia and knee hyperalgesia. Female mice showed alleviation of mechanical allodynia, knee hyperalgesia, and weight bearing deficits after macrophage depletion at 12 weeks post PMX. Macrophage depletion did not affect the degree of cartilage degeneration, osteophyte width, or synovitis in either sex. Flow cytometry of the DRG revealed that macrophages and neutrophils were reduced after AP20187 treatment. In addition, in the DRG, only MHCII+ M1-like macrophages were significantly decreased, while CD163+MHCII-M2-like macrophages were not affected in both sexes. DRG bulk RNA-seq revealed that Cxcl10 and Il1b were upregulated with DMM surgery compared to naive mice, and downregulated in DMM after acute macrophage depletion. ConclusionsAcute systemic macrophage depletion reduced the levels of pro-inflammatory macrophages in the DRG and alleviated pain-related behaviors in established surgically induced OA in mice of both sexes, without affecting joint damage. Overall, these studies provide insight into immune cell regulation in the DRG during OA.

neuroscience↗

bioRxiv2024

Reduced Capsaicin-Induced Mechanical Allodynia and Neuronal Responses in the DRG in the Presence of Shp1 Overexpression

Transient Receptor Potential Vanilloid 1 (TRPV1) is a nonselective cation channel expressed by pain-sensing neurons and has been an attractive target for the development of drugs to treat pain. Recently, Src homology region 2 domain-containing phosphatase-1 (SHP-1) was shown to dephosphorylate TRPV1 in dorsal root ganglia (DRG) neurons, which was linked with alleviating different pain phenotypes. These previous studies were performed in male rodents only and did not directly investigate the role of SHP-1 in TRPV-1 mediated sensitization. Therefore, our goal was to determine the impact of Shp1 overexpression on TRPV1-mediated neuronal responses and capsaicin-induced pain behavior in mice of both sexes. Twelve-week-old male and female mice overexpressing Shp1 (Shp1-Tg) and their wild type (WT) littermates were used. Shp1 overexpression was confirmed in the DRG of Shp1-Tg mice by RNA in situ hybridization and RT-qPCR. Trpv1 and Shp1 were found to be co-expressed in DRG sensory neurons in both genotypes. Functionally, this overexpression resulted in lower magnitude intracellular calcium responses to 200 nM capsaicin stimulation in DRG cultures from Shp1-Tg mice compared to WTs. In vivo, we tested the effects of Shp1 overexpression on capsaicin-induced pain through a model of capsaicin footpad injection. While capsaicin injection evoked nocifensive behavior (paw licking) and paw swelling in both genotypes and sexes, only WT mice developed mechanical allodynia after capsaicin injection. We observed similar level of TRPV1 protein expression in the DRG of both genotypes, however, a higher amount of tyrosine phosphorylated TRPV1 was detected in WT DRG. These experiments suggest that, while SHP-1 does not mediate the acute swelling and nocifensive behavior induced by capsaicin, it does mediate a protective effect against capsaicin-induced mechanical allodynia in both sexes. The protective effect of SHP-1 might be mediated by TRPV1 dephosphorylation in capsaicin-sensitive sensory neurons of the DRG.

neuroscience↗