Search Results (175)

Background: Chronic Obstructive Pulmonary Disease (COPD) is a progressive, incurable condition marked by irreversible airflow limitation and systemic inflammation. Cardiovascular comorbidities, particularly pulmonary hypertension (PH), exacerbate disease severity. While cigarette smoke is a well-known trigger, non-smoking-related inflammatory pathways remain underexplored. This study investigates vascular remodeling in a murine model of inflammation induced by chronic exposure to house dust mite Farinae (HDM). Methods: Female C57BL/6 mice were sensitized with HDM in Freund’s Complete Adjuvant and challenged intranasally with HDM for six weeks. Lung inflammation, mucus hypersecretion, and vascular remodeling were evaluated via BAL, histology, immunofluorescence, echocardiography, gene expression, proteomics, and FlexiVent pulmonary function tests (FlexiVent system). Results: HDM exposure induced a mixed inflammatory response, with elevated neutrophils, monocytes, and lymphocytes in BALF. Mucus hyperproduction (increase in MUC5AC/MUC5B) and impaired lung function (reduced FEV0.1/FVC) were observed. Vascular remodeling was evidenced by increased wall thickness, α-SMA expression, and collagen deposition. Proteomic analysis revealed dysregulation of endothelial markers and protease/antiprotease imbalance. HIF1-α was significantly upregulated in lung tissue and correlated with vascular and epithelial remodeling. Conclusions: Chronic HDM exposure in mice recapitulates key features observed in subsets of COPD and PH, including inflammation-driven airway and vascular remodeling. HIF1-α emerges as a central regulator, linking hypoxia to structural changes. This model offers insights into the effect of non-smoking-related inflammatory pathways on bronchial and vascular remodeling that are potentially relevant for subgroups of COPD patients and highlights HIF1-α as a potential therapeutic target. Full article

Delta-3-carene (CAR), a monoterpene derived from plant essential oils, exhibits promising biological properties, including anti-inflammatory, antioxidative, anxiolytic, and antimicrobial activities. Therefore, this study aimed to investigate the anti-inflammatory effects of CAR by analyzing the activity of this terpene on leukocyte activation through the evaluation of cell migration in in vitro and in vivo models. Cell viability analysis demonstrated that CAR (3, 10, 30, and 90 μg/mL) exerted no cytotoxic effects and significantly reduced in vitro neutrophil chemotaxis toward N-formylmethionyl-leucyl-phenylalanine (fMLP). Furthermore, CAR decreased phagocytosis in zymosan-stimulated neutrophils in vitro. In Swiss mice, oral CAR treatment, at doses of 25, 50, and 100 mg/kg, reduced inflammatory and antinociceptive parameters in zymosan-induced peritonitis, carrageenan-induced paw edema and mechanical hyperalgesia, and nociception induced by acetic acid and formalin models. In the persistent inflammation model (for 21 days) induced by complete Freund’s adjuvant (CFA), daily CAR treatment (50 mg/kg) reduced paw edema and mechanical hyperalgesia in all evaluated times at 6, 11, 16, and 21 days after CFA-induced inflammation. In conclusion, our data demonstrated that CAR modifies acute and chronic inflammatory responses, highlighting its potential therapeutic application in managing inflammation and pain. Full article

Background/Objectives: Betanin (BET), a prominent phytochemical mainly derived from Beta vulgaris, exhibits strong anti-inflammatory and antioxidant activities owing to its distinctive chemical structure. Nevertheless, its potential analgesic effect in the context of inflammatory pain remains insufficiently explored. Accordingly, this study investigated the analgesic effects of BET in a complete Freund’s adjuvant (CFA)-induced rat model of inflammatory pain. Methods: Rats received a single subcutaneous injection of 100 µL CFA to induce inflammatory pain, followed by oral administration of BET at doses of 40 or 80 mg/kg/day for 14 days. Results: BET treatment significantly reduced paw edema and improved HPL (hot plate latency) in CFA-injected rats. Biochemically, in the ipsilateral spinal cord of rats, BET at both 40 and 80 mg/kg significantly increased IL-4, and only the 80 mg/kg dose significantly reduced oxidative stress (MDA) and IL-1β. TNF-α levels were slightly reduced at both doses and did not reach statistical significance versus CFA. At the molecular level, miR-107 was significantly downregulated by BET at 80 mg/kg (but not 40 mg/kg), while miR-145 was significantly upregulated by both 40 mg/kg and 80 mg/kg compared to CFA. Pearson’s correlation indicated that miR-107 was positively correlated with MDA, IL-1β and TNF-α but negatively with IL-4, whereas miR-145 was positively correlated with IL-4 but negatively with IL-1β. PCA biplot analysis corroborated these findings, showing simultaneous presence of MDA, IL-1β, TNF-α, and miR-107 with CFA, and IL-4 and miR-145 were only related to control and CFA+BET80 groups. In addition, using transmission electron microscopy imaging, we found that BET alleviated neuronal damage in CFA-treated rats. Furthermore, molecular docking analysis predicted that BET may exhibit stable binding interactions with several inflammation- and apoptosis-related targets, including AKT1, mTOR, IKKβ, TNF-α, IL-1β, COX-2, caspase-3, caspase-7, and caspase-8, supporting its multi-target anti-inflammatory and antiapoptotic effects. Conclusions: Overall, our data suggest that BET can possibly exert analgesic effects in CFA-induced inflammatory pain by modulating oxidative stress and favoring a shift toward an anti-inflammatory status. These effects coincided with downregulation of miR-107, overexpression of miR-145, and improvements in inflammatory pain behaviors. Further investigations are required to validate the involvement of specific miRNA- and pathway-mediated effects. Nevertheless, our findings highlight BET as a promising natural candidate for future development of anti-inflammatory and analgesic strategies. Full article

Aims: Coronary heart disease (CHD) associated with rheumatoid arthritis (RA) is a primary driver of mortality in RA patients. In this study, we sought to establish a combined rat model of CHD and RA by integrating cardiac ischemia/reperfusion (I/R), high-fat diet (HFD), and intradermal administration of bovine type II collagen emulsified in complete Freund’s adjuvant. The aim of constructing this model is to investigate and analyze the pathogenesis of RA-induced CHD under the modulation of HFD and cardiac I/R exposure. Methods and Results: Sixty-four male Sprague–Dawley rats were randomly categorized into eight groups (n = 8 per group): control, I/R, HFD, collagen-induced arthritis (CIA), I/R + CIA, HFD + CIA, I/R + HFD, and I/R + HFD + CIA groups (n = 8 per group). We applied Synchrotron radiation-based X-ray micro-computed tomography (micro-CT) to observe the structural changes within the model over time. To further elucidate molecular mechanisms, transcriptome RNA-seq analysis was carried out to identify key signaling pathways, with particular emphasis on the homeostasis of Toll-like receptor 4 (TLR4)/Myd88 signaling in the ischemic myocardium. Furthermore, we conducted in vivo shRNA-mediated knockdown of polymerase I and transcription release factor (PTRF) and evaluated the co-localization of PTRF and TLR4 through immunofluorescence experiments. It is worth mentioning that our rat model of RA-induced (CHD) under a high-fat diet effectively manifested the relevant pathological features that align with the Traditional Chinese Medicine (TCM) definition of “bi” syndrome. The results indicate that the combined stimulation of HFD and CIA significantly elevated cardiac injury markers (CK-MB, LDH, CRP, and c-TNT) and was accompanied by a more severe expansion of the infarct area and increased cardiomyocyte apoptosis compared to the I/R group alone. In addition, the histopathological evaluation revealed significantly aggravated myocardial inflammation and fibrosis deposition, accompanied by extensive areas of tissue damage, further indicating a state of heightened inflammation and severe cardiac degenerative changes. Consistently, myocardial tissues from rats in the I/R + CIA + HFD group exhibited robust activation of the TLR4/MyD88 signaling pathway and a pronounced elevation in the p-JNK/JNK ratio. Moreover, pronounced co-localization between PTRF and TLR4 was evident in small vessels surrounding the infarcted myocardium. Importantly, AAV-mediated knockdown of PTRF attenuated the HFD- and CIA-induced exacerbation of myocardial injury in I/R rats. Conclusions: We successfully established a rat model of CHD with rheumatic syndrome using I/R in combination with RA and HFD. The present findings suggest that the PTRF-related TLR4/MyD88-JNK signaling pathway may act as an important regulatory mechanism underlying myocardial injury aggravated by combined HFD and CIA stimulation. Full article

Background/Objectives: Rheumatoid arthritis (RA) is an autoimmune disorder manifesting as joint destruction and synovial inflammation, with the aberrant activation of fibroblast-like synoviocytes (FLSs) functioning as a critical pathological mechanism. Liquiritigenin (LIQ), a natural flavonoid extracted from licorice root, possesses anti-inflammatory and antioxidant activities; however, its efficacy and mechanism in RA pathological models remain unclear. This study aimed to investigate the anti-RA effects of LIQ mediated through FLSs and its underlying mechanisms. Methods: Complete Freund’s adjuvant (CFA)-induced rat model and TNF-α-stimulated MH7A cell model were employed to assess the anti-RA effects and underlying mechanisms. In vivo experiments examined the effects of LIQ on RA manifestations, joint damage, and inflammatory responses in CFA-induced rats, while in vitro experiments explored its effects on aberrant activation, oxidative stress, and inflammation in TNF-α-stimulated MH7A cells. The regulatory effects of LIQ on the Nrf2/NF-κB/NLRP3 signaling pathway were validated by immunofluorescence and Western blotting in vivo and in vitro. Results: LIQ alleviated joint swelling and bone damage, reducing synovial cellular infiltration and hyperplastic changes in CFA-induced rats. Furthermore, LIQ inhibited proliferation, migration, and invasion while reducing reactive oxygen species levels in TNF-α-stimulated MH7A cells, and decreased IL-1β and IL-18 levels in rat serum and MH7A cell supernatants. Moreover, LIQ activated Nrf2 and inhibited NF-κB and NLRP3, thereby attenuating inflammatory responses and alleviating oxidative stress. Administration of the Nrf2 inhibitor ML385 partially reversed its suppressive effects on inflammatory responses and oxidative stress in vivo and in vitro. Conclusions: LIQ exerted anti-RA effects in FLSs by suppressing inflammation and aberrant activation. Its mechanism may involve modulation of the Nrf2/NF-κB/NLRP3 signaling pathway. Full article

Rheumatoid arthritis (RA) is a chronic disease that primarily manifests as symmetrical joint inflammation. Although Coix Seed Oil (CSO) has demonstrated anti-inflammatory effects in RA rat models, its systemic metabolic regulatory mechanisms remain unclear. Therefore, we aimed to investigate whether CSO ameliorates RA by modulating inflammation-associated metabolic pathways. Ultra-High-Performance Liquid Chromatography (UHPLC)-Q Exactive HF-X-MS-based metabolomics was used to profile metabolites in the synovial tissue and serum of complete Freund’s adjuvant (CFA)-induced RA rats. Systematically altered metabolites and their associated pathways were identified using multivariate analysis and pattern recognition. CSO treatment modulated 16 RA-related biomarkers in rat synovial tissues and 12 in the serum, which mainly affected amino acids, arachidonic acids, lipids, sphingolipids, and carnitines. These metabolites were associated with eight perturbed metabolic pathways that were predominantly involved in inflammatory responses. This study demonstrated that CSO has significant anti-RA effects on pharmacodynamic activity and metabolic network regulation. Additionally, inflammation-associated metabolic pathways are closely linked to the therapeutic efficacy of CSO in RA treatment. Full article

Background: Mas-related G-protein-coupled receptor b4 (Mrgprb4)-lineage neurons in the peripheral nervous system are a type of C fibers in hairy skin. Our prior work demonstrated that these neurons respond to both noxious and innocuous mechanical and thermal stimuli. Ablating them eliminates the pleasant sensation elicited by gentle pressure on a mouse’s nape. However, their potential role in mitigating pain and pain-related negative emotions in response to somatic stimuli remains unclear. Methods: A CFA-induced chronic pain and anxiety comorbidity model was established in C57BL/6J mice. In vivo calcium imaging of dorsal root ganglia (DRG) neurons in Mrgprb4-GCaMP6s transgenic mice characterized neuronal responses to transcutaneous electrical nerve stimulation (TENS) at the Zusanli (ST36) acupoint. Optogenetic activation (Mrgprb4-ChR2 mice) and viral ablation of Mrgprb4-lineage neurons were employed to evaluate their role in mediating TENS effects on mechanical pain thresholds and anxiety-like behaviors. Results: In vivo calcium imaging revealed that 0.5 mA TENS preferentially activated Mrgprb4-lineage neurons compared to 2.0 mA TENS. In CFA model mice, 0.5 mA TENS at ST36 significantly increased mechanical pain thresholds and reduced anxiety-like behaviors in the open-field test. Optogenetic activation of Mrgprb4-lineage neurons at ST36 replicated these analgesic and anxiolytic effects, demonstrating the sufficiency of these neurons for therapeutic outcomes. Conversely, viral ablation of L3–L5 Mrgprb4-lineage neurons substantially attenuated the therapeutic effects of 0.5 mA TENS for both pain relief and anxiety reduction, indicating their necessity in mediating TENS efficacy. Conclusions: Mrgprb4-lineage neurons serve as critical peripheral mediators of TENS-induced analgesia and anxiolysis. These findings identify a specific neuronal population underlying the therapeutic effects of somatic stimulation at ST36, providing mechanistic insights that may guide optimization of TENS parameters for treating chronic pain and comorbid anxiety in clinical settings. Full article

Background. Inbred mouse models of autoimmune myocarditis are routinely used to investigate the immune mechanisms underlying dilated cardiomyopathy. However, their translational relevance is limited because observations made in a single inbred strain may not reflect those of outbred human populations. This limitation can be overcome by using Diversity Outbred (DO) mice, whose genetic variability is comparable to that of humans. Methods. To investigate the utility of DO mice, we characterized their immune cell distributions and induced myocarditis by immunization with porcine cardiac myosin (PCM) emulsified in complete Freund’s adjuvant. Antigen-specific T cell and antibody responses were evaluated using lymphocytes and serum samples, respectively, and hearts were examined histologically for inflammatory changes. Results. First, we noted no significant variations in the majority of immune cell populations, which include T cells and B cells. However, NK cells, double positive for CD49b and NK1.1, were lacking in both sexes. While we noted sex differences in the expression of major histocompatibility complex class II molecules in antigen-presenting cells, expression of costimulatory molecules was similar in both sexes. Second, upon immunization, we demonstrated that the PCM was immunogenic, and the PCM-reactive T cell responses were generated in both males and females, as measured by a proliferation assay. Third, cytokine analysis revealed marginal detection of Th1 (IFN-γ) and Th17 (IL-17 and IL-22) cytokines, mainly with three doses of immunization. Fourth, determination of PCM-reactive antibody responses revealed significant amounts of IgG1 and IgG2b isotypes. Finally, histological analysis revealed varying degrees of myocarditis in individual mice of both sexes. Conclusions. Our data suggest that mild autoimmune myocarditis can be induced in DO mice. However, to capture the heterogeneity in disease susceptibility, large sample cohorts are required. Full article

Rheumatoid arthritis involves chronic synovitis and immune-metabolic dysregulation, highlighting a need for multi-target therapies that jointly modulate metabolism and inflammation. We developed glycyrrhiza protein–paeoniflorin self-assembled nanoparticles (GP-PF NPs) and investigated their anti-arthritic mechanism in adjuvant-induced arthritis (AIA) mice, using UHPLC-Orbitrap-MS-based metabolomics. Male C57BL/6 mice (n = 42) were assigned to the control, model, GP-PF NPs, paeoniflorin, glycyrrhiza protein, physical mixture, and celecoxib groups. All groups except controls received complete Freund’s adjuvant, and treatments were given intraperitoneally for 10 days. GP-PF NPs produced the greatest reduction in paw thickness versus the model (p < 0.0001) and outperformed all other active treatments, which was consistent with the improved histopathology. UHPLC-Orbitrap-MS detected 473 serum metabolites, and the model group showed 59 significant changes versus the control. GP-PF NPs significantly modulated 108 metabolites and yielded robust OPLS-DA separation from the model (R²Y = 0.98; Q² = 0.742). Venn and pathway analyses identified 43 NP-specific metabolites enriched in glycerophospholipid metabolism, including glycerophosphocholine, 1-oleylglycerophosphocholine, PE (16:0/16:0), phosphocholine, and sphingosine-1-phosphate. These metabolites were selectively normalized toward control levels by GP-PF NPs. qPCR further showed that GP-PF NPs significantly reduced synovial PI3K, AKT, mTOR, NLRP3, Caspase-1, and GSDMD mRNA overexpression (all p < 0.001 vs. model). Correlation analysis indicated significant associations between key serum lipids and synovial genes (e.g., PI3K positively correlated with several metabolites, r = 0.71–0.82; mTOR negatively correlated with sphinganine 1-phosphate and glycerophosphocholine, r = −0.65 and −0.54). These data suggest that GP-PF NPs ameliorate AIA and are associated with the normalization of glycerophospholipid-related metabolic perturbations and reduced synovial mRNA expression of the PI3K/AKT/mTOR-NLRP3 pathway, supporting their potential as a metabolism-inflammation preclinical oriented anti-arthritic nanomedicine. Full article

Rheumatoid arthritis remains a major clinical challenge requiring safer and more effective alternatives to conventional non-steroidal anti-inflammatory drugs (NSAIDs). This pioneering study evaluated the anti-inflammatory, analgesic, antioxidant, and safety effects of Artemisia herba alba extract in complete Freund’s adjuvant (CFA)-induced arthritis in rats. Animals received oral Artemisia herba alba (250 or 500 mg/kg), indomethacin (3 mg/kg), or saline for 15 days. CFA induced marked joint inflammation, mechanical allodynia, locomotor impairment, and oxidative stress. Treatment with Artemisia herba alba 500 mg/kg significantly reduced paw swelling, improved mobility in the open-field test, and markedly attenuated pain hypersensitivity. In parallel, biochemical analyses showed restoration of total antioxidant capacity, prevention of lipid peroxidation, and normalization of creatinine levels. Unlike indomethacin, which induced hepatotoxicity (elevated ASAT (Aspartate Aminotransferase)/ALAT (Alanine Aminotransferase)) and pronounced oxidative stress, Artemisia herba alba preserved liver and kidney function and did not produce histopathological alterations. Histological findings further indicated reduced inflammatory infiltrate and cartilage protection, particularly at 500 mg/kg. Taken together, these results suggest that Artemisia herba alba displays a multitarget effect with anti-inflammatory, antioxidant and analgesic activity, along with a superior safety profile compared with indomethacin, consistent with reports from other phenolic-rich natural products. However, findings should be interpreted in light of the small sample size and preclinical study design, and further mechanistic and clinical investigations are warranted. Full article

Background: Experimental autoimmune thyroiditis is an important animal model for studying Hashimoto’s thyroiditis. Our aim was to develop the model using CBA/J-DR3 mice expressing human HLA-DR3, which is associated with autoimmune thyroiditis in humans, to better simulate human autoimmune thyroiditis. Such a humanized model can be used to test specific antigen therapies for autoimmune thyroiditis. Methods: CBA/J-DR3 mice were produced by back-crossing B6-DR3 mice to the CBA/J background. Female CBA/J-DR3 mice were immunized with human thyroglobulin (Tg) in complete Freund’s adjuvant on days 0 and 7. On day 21, mice were sacrificed, blood collected, spleen and thyroid harvested for analysis. Splenocytes were analyzed for T cell responses to Tg and its major T-cell epitope in human autoimmune thyroiditis, Tg.2098. Serum anti-thyroglobulin antibodies were measured by ELISA, and thyroid-stimulating hormone was measured using the Luminex assay. Thyroid histology and immunohistochemistry were examined. Results: Immunized CBA/J-DR3 mice showed significant T cell proliferation in response to Tg (stimulation index 3.4 ± 4.5) and Tg.2098 (1.5 ± 0.7). Anti-thyroglobulin antibody levels were elevated in immunized mice when compared to control mice (2.05 ± 0.75 vs. 0.15 ± 0.06, p < 0.0001). T cells demonstrated higher reactivity to thyroid antigens by enhanced production of pro-inflammatory cytokines. Thyroid immunohistochemistry revealed mild CD3-positive T-cell infiltration. Conclusions: This novel humanized CBA/J-DR3 mouse model of Hashimoto’s thyroiditis demonstrates key features of human autoimmune thyroiditis. The HLA-DR3 background and the immune response to Tg and Tg.2098 enhance translational relevance, making this a valuable model for studying thyroid disease pathogenesis and testing targeted immune-modifying therapies. Full article

Previous in vivo studies have clearly demonstrated that the intravenous administration of the carotenoid astaxanthin (AST) suppresses the excitability of rat trigeminal spinal nucleus caudalis (SpVc) neurons. This action is hypothesized to be mediated through the inhibition of both voltage-gated Ca²⁺ (Cav) channels and excitatory glutamate receptor transmission. The objective of this study was to determine whether acute intravenous administration of AST alleviates the hyperexcitability of SpVc wide dynamic range (WDR) neurons in a rat model of inflammation. Neuronal responses to both nociceptive and non-nociceptive mechanical stimulation were evaluated using an in vivo electrophysiological model. One day following inflammation induced by Complete Freund’s Adjuvant (CFA), the mechanical escape threshold was significantly reduced compared to pre-injection baseline values. Subsequently, extracellular single-unit recordings were performed on SpVc WDR neurons in anesthetized, inflamed rats. The neuronal responses to both non-noxious and noxious orofacial mechanical stimuli were then analyzed. Acute intravenous administration of AST at 1 and 5 mM elicited a dose-dependent reduction in the mean firing frequency of SpVc WDR neurons in response to noxious mechanical stimuli. This inhibition peaked within 10 min and was fully reversed after approximately 25 min. Importantly, AST preferentially inhibited the discharge frequency of SpVc WDR neurons in response to noxious stimulation, exhibiting a significantly greater effect than on the response evoked by non-noxious stimulation (41.5 ± 3.0% vs. 20.7 ± 4.2%, p < 0.05). Collectively, these findings demonstrate that acute intravenous administration of AST effectively suppresses noxious synaptic transmission within the SpVc during inflammation. We propose that this suppressive effect is mediated by the inhibition of upregulated Cav channels and glutamate receptors. Consequently, AST is implicated as a promising therapeutic candidate for the management of trigeminal inflammatory pain, given its potential for a favorable safety profile compared to conventional treatments. Full article

The clinical success of calcium phosphate bone grafts (CPs) largely depends on the body’s immune response. However, traditional biocompatibility tests use healthy organisms and cannot predict effectiveness in patients with common chronic inflammatory diseases. This study examines how inflammation modulates the immune response, in vitro and in vivo, to low-temperature biomimetic CPs: dicalcium phosphate dihydrate (DCPD), octacalcium phosphate (OCP), and hydroxyapatite (HAp). In vitro studies involved human monocytes, macrophages, lymphocytes, and mesenchymal stromal cells (MSCs), with or without pro-inflammatory activation. In vivo biocompatibility was assessed via subcutaneous implantation in rats, with or without Complete Freund’s Adjuvant (CFA)-induced inflammation. Under normal conditions, all CP caused minimal immune reactivity. Inflammation-activated macrophages, however, triggered an acute reaction with significantly increased TNF-α and IL-1β secretion. Healthy and inflamed animals showed sharp contrasts. Although all materials exhibited thickened fibrous capsules during inflammation, biocompatibility varied markedly: DCPD performed best by promoting angiogenesis with minimal inflammation; HAp provoked the most severes response, including tissue necrosis and signs of rejection; OCP showed intermediate effects, with angiogenesis but notable fibrosis. Inflammatory processes critically influence CP biocompatibility; materials biocompatible in healthy organisms can induce fibrosis or rejection under inflammation. Disease-relevant, immune-challenged models are essential to predict clinical efficacy and safety. Full article

Background: Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by persistent joint inflammation and progressive bone destruction. However, its complex pathogenesis remains poorly understood, and effective therapeutic targets are still lacking. Objective: This study aimed to identify key genes associated with RA and elucidate their biological significance by integrating bioinformatic analysis with experimental validation. Methods: Whole-transcriptome data from the anterior cingulate cortex (ACC) of Complete Freund’s Adjuvant (CFA)-induced inflammatory pain and control mice (GSE147216 dataset, GEO database) were collected from NCBI (National Center for Biotechnology Information). Differentially expressed genes (DEGs) were first identified. Subsequent analyses included Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment, construction of a protein–protein interaction (PPI) network, and identification of hub genes using a Random Forest machine learning algorithm. Quantitative PCR (qPCR) was performed to validate gene expression levels. Results: A total of 76 DEGs were identified, including 64 upregulated and 12 downregulated genes. Among them, Fn1 (fibronectin 1), Bgn (biglycan), and Lum (lumican) were identified as hub genes. Functional enrichment analysis revealed inflammatory responses, extracellular matrix (ECM) remodeling, and the TGF-β signaling pathway. qPCR validation confirmed significant upregulation of Fn1, Bgn, and Lum mRNA in the CFA group. Conclusions: This study highlights the potential roles of Fn1, Bgn, and Lum in the central sensitization associated with inflammatory pain, offering insights relevant to RA. Full article

The nuclear kinases mitogen- and stress-activated kinase 1 and 2 (MSK1 and MSK2), through regulating transcriptional processes, are pivotal for various adaptive responses, including inflammation, learning and addiction. Transcriptional alterations in neurons and glia cells within the pain signal-processing (nociceptive) pathway, including the superficial spinal dorsal horn (SSDH), are critical for the development and persistence of inflammatory pain that results from tissue injuries and subsequent inflammatory reactions. While previous reports have indicated that MSK1 contributes to transcriptional changes in inflamed tissues, the impact of MSK1 on nociceptive processing in the SSDH are poorly understood at present. Here, we report MSK1 immunoreactivity (IR) in a group of excitatory and inhibitory neurons as well as in microglia and oligodendrocytes in the SSDH. Injecting Complete Freund’s Adjuvant into the mouse hind paw produced robust non-evoked pain-related behavior, which was significantly attenuated by global depletion of MSK1. In wild-type mice, the inflammatory pain was accompanied by transient MSK1-dependent phosphorylation of the MSK1 downstream effector histone 3 at serine 10 at one hour but not two days after the injection; still, the number of nuclei exhibiting activated MSK1 expression remained highly restricted even at 1 h post-injection. Our data indicate that MSK1 contributes to inflammatory pain via epigenetic and transcriptional alterations; however, once initiated, MSK1’s downstream effects do not require further drive from the persistent activity of the MSK1 signaling pathway in the SSDH. Full article