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Arnab, S.

Publications and source records attributed to Arnab, S..

4 recordsLinked to original sources

TNFR2 Agonism as a Sex-Specific Therapy for Novel Osteoarthritis-Induced Cardiac Dysfunction

Osteoarthritis (OA), a degenerative joint disease, is associated with increased systemic inflammation, chronic pain, and cardiovascular dysfunction. Epidemiological evidence establishes that OA increases the risk of cardiovascular disease (CVD) threefold, yet the causal role of OAs contributions remains underexamined. We assessed cardiac function longitudinally following destabilization of the medial meniscus (DMM) surgery to induce osteoarthritis in mice. DMM-mice exhibited significant, sexually dimorphic alterations in echocardiographic parameters. Female DMM mice developed impaired relaxation with altered E/A ratios, increased E/e ratios, and prolonged intraventricular relaxation time with no change in ejection fraction, while male DMM mice showed progressive systolic dysfunction with decreasing ejection fraction, increased E/e ratio, and prolonged intraventricular contraction time. Transcriptomic profiles and biochemical analyses demonstrated divergent cellular responses involving fibrosis and oxidative stress in female mice, whereas autophagic and apoptotic responses were observed in male mice. Using a tumor necrosis factor 2 (TNFR2) agonist shown to reduce systemic inflammation, we investigated its potential therapeutic role in the context of OA-induced cardiovascular dysfunction. TNFR2 agonism proved to be effective both prophylactically and therapeutically for female diastolic dysfunction. While prophylactic and therapeutic administration delayed male systolic dysfunction, the efficacy declined over time. Our findings demonstrate evidence of a novel sexually dimorphic model of OA-induced CVD that recapitulates the sexually dimorphic pattern of patient phenotypes and a promising new therapeutic approach to CVD. Translational RelevanceOsteoarthritis patients have higher, often unrecognized, cardiovascular risk, yet preclinical models linking joint disease to cardiac dysfunction remain unexplored. Using a murine preclinical model of OA reveals the key findings. First, OA alone drives sex-specific cardiac phenotypes - females develop diastolic dysfunction, whereas males develop progressive systolic impairment. Second, selective TNFR2 agonism prevents and reverses OA-induced diastolic dysfunction in female mice and delays systolic decline in males. These findings suggest sex-dependent cardiac monitoring in OA patients and indicate that TNFR2-targeted therapy will likely be a sex-informed intervention to provide cardioprotective benefit. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=130 SRC="FIGDIR/small/736778v3_ufig1.gif" ALT="Figure 1"> View larger version (42K): org.highwire.dtl.DTLVardef@819a80org.highwire.dtl.DTLVardef@c6646eorg.highwire.dtl.DTLVardef@eb86aborg.highwire.dtl.DTLVardef@d68292_HPS_FORMAT_FIGEXP M_FIG C_FIG

physiology↗

Hippocampal CA3 Nex/Neurod6+ neuron-specific TNFR2 alleviates chronic neuropathic pain by sex-dependently engaging opioid and endocannabinoid pathways

Chronic neuropathic pain (CNP) develops as a result of persistent neuroinflammation and maladaptive synaptic plasticity in the central nervous system following nerve injury. While tumor necrosis factor receptor 2 (TNFR2) signaling has been extensively studied in pain resolution, the expression of this receptor on specific neuronal populations and molecular pathways involved in spontaneous pain recovery still remains poorly defined. In this study, we investigated the role of TNFR2 signaling within hippocampal Nex/Neurod6 pyramidal neurons in promoting recovery from chronic constriction injury (CCI), a well-established rodent model of neuropathic pain. To achieve neuron-specific deletion of TNFR2, we generated tamoxifen-inducible conditional knockout mice (NexCreERT2:TNFR2F/F). We demonstrate that knocking out TNFR2 from Nex neurons prevents spontaneous pain recovery in both males and females. Thus, establishing that a supraspinal TNFR2 neuroimmune axis is necessary for pain recovery. Exogenous administration of a TNFR2 agonist at 7, 10, and 13 dpi (i.p.) significantly improved mechanical withdrawal thresholds in both sexes of wild-type mice but did not alleviate pain in Nex-specific TNFR2 knockouts, indicating that neuronal TNFR2 expression is required for TNFR2-mediated analgesia. Bulk RNA sequencing of hippocampal tissue collected at six weeks after CCI revealed that TNFR2 activation upregulates genes such as Pomc, involved in the opioid pathway, and oleoyl-ACP-hydrolase (OLAH), involved in the endocannabinoid pathway. Consistent with these findings, immunostaining and Western blot analyses showed that TNFR2 agonism restored cornu ammonis (CA3) region POMC and {beta}-endorphin protein levels that were otherwise suppressed after CCI. Behavioral experiment demonstrated that systemic blockade of the {micro}-opioid receptor with naltrexone (administered daily from 7-21 dpi (s.c.)) completely prevented TNFR2-mediated pain recovery in males but only partially in females. In contrast, inhibition of cannabinoid 1 receptor (CB1R) signaling with AM251 (administered at 7, 14, and 21 dpi (i.p.)) abolished TNFR2-driven analgesia in both sexes. Together, these results reveal that hippocampal TNFR2 signaling in Nex/Neurod6 neurons is critical in recovery from chronic neuropathic pain. TNFR2 activation promotes analgesia by engaging endogenous {beta}-endorphin/{micro}-opioid and endocannabinoid pathways in a sex-dependent manner, establishing TNFR2 agonism as a promising non-addictive therapeutic approach for chronic pain resolution. SignificanceChronic neuropathic pain (CNP) results from persistent neuroimmune signaling and is driven by maladaptive circuit plasticity. Due to the complexity of factors contributing to CNP, it often leaves patients with few treatment options, which, unfortunately, are either temporary or might be addictive. We have characterized a novel supraspinal mechanism through which tumor necrosis factor receptor 2 (TNFR2) signaling, specifically in hippocampal Neurod6/Nex+ expressing pyramidal neurons, is necessary for pain recovery following nerve injury. Pharmacological activation of TNFR2 in these neurons alleviates pain by engaging both endogenous opioid and endocannabinoid signaling pathways. We specifically demonstrate that TNFR2 agonism upregulates proopiomelanocortin (POMC) expression and {beta}-endorphin levels in the hippocampus. We further identify that pharmacological inhibition of either the -opioid receptor or cannabinoid 1 (CB1) receptor is sufficient to impair the effectiveness of TNFR2 agonist mediated pain resolution. Our findings thus uncover a novel neuroimmune mechanism where the TNFR2 agonist, exogenously activating the pro-resolving TNFR2, mitigates CNP by releasing endogenous pain neuromodulators. Here, we highlight that TNFR2 agonism could serve as a non-addictive therapeutic strategy for the resolution of chronic neuropathic pain.

pharmacology and toxicology↗

Sex-Specific Characterization of a Novel Osteoarthritis-Induced Heart Failure Model in Mice

Chronic low-grade inflammation is increasingly recognized as a key driver of heart failure (HF) progression; however, the direct contribution of systemic inflammatory disorders such as osteoarthritis (OA) remains unclear. Here, we establish a murine model of OA-induced HF using destabilization of the medial meniscus (DMM) to induce systemic inflammation and sex-specific cardiac remodeling. Longitudinal echocardiography revealed that females develop diastolic dysfunction with preserved ejection fraction, resembling HFpEF, whereas males exhibit progressive systolic impairment, consistent with a transitional HFmrEF-to-HFrEF phenotype. Morphometric and histological analyses confirmed concentric hypertrophy in females and eccentric remodeling in males. Transcriptomic profiling identified distinct molecular programs--females upregulated extracellular matrix, cytoskeletal, and calcium-handling genes, while males showed enrichment of inflammatory and immune signaling pathways. Immunoblot analyses further validated these sex-specific molecular signatures: females displayed increased ANP, BNP, Sirt1, and AMPK expression, consistent with metabolic resilience and fibrotic remodeling, whereas males exhibited elevated p38 MAPK, NF-{kappa}B, LC3B, and cleaved caspase-3, reflecting heightened inflammation, autophagy, and apoptosis. Both sexes demonstrated downregulation of mitochondrial and lipid metabolic proteins, indicating convergent energetic stress. Collectively, these findings identify OA as a systemic inflammatory driver of heart failure, delineate the molecular and proteomic basis of sex-dependent cardiac remodeling, and introduce a translational preclinical model that recapitulates the clinical heterogeneity of HFpEF and HFmrEF/HFrEF, providing a foundation for mechanistic and therapeutic exploration.

molecular biology↗

ER oxidoreductin-1α and unfolded protein response as sex-dependent drivers of cardiorenal dysfunction in experimental autoimmune encephalomyelitis

BackgroundMultiple sclerosis (MS) is associated with increased cardiovascular and renal morbidity, but mechanisms linking CNS autoimmunity to peripheral organ injury remain poorly defined. We tested the hypothesis that experimental autoimmune encephalomyelitis (EAE) induces cardiorenal dysfunction via sex-specific dysregulation of endoplasmic reticulum (ER) oxidoreductases and unfolded protein response (UPR) signaling. MethodsAdult female and male C57BL/6J mice [10-12 weeks] and IRE1C148S knock-in mice underwent non-pertussis toxin EAE (nPTX-EAE) induced with 100{micro}g MOG35-55 in CFA and 200{micro}g heat-inactivated MTB with a booster at 7 days. Controls received all components except MOG. Motor scoring was done daily and EN460 (ERO1 inhibitor, 10 mg/kg IP) was given twice weekly beginning at 10DPI. Echocardiography and renal Doppler (Vevo 2100) were performed at 36-38DPI with primary outcomes of LV systolic/diastolic function and renal perfusion with tissue collected at 40DPI. LV and kidney were analyzed via western blot for ERO1, PDIA1, Prdx4, 4HNE, and BiP. Data are expressed as mean {+/-} SEM with two-way ANOVA/Tukeys post hoc or Mann Whitney test performed and outliers identified by ROUT (Q=1%). ResultsSixty-seven percent of immunized mice developed motor deficits. At 36-38DPI, EAE reduced ejection fraction and fractional shortening while increasing IVCT, IVRT, and myocardial performance index without hypertrophy. Renal resistive index increased and end-diastolic velocity decreased in addition to reduced Bowmans space at 40DPI. Females showed upregulated LV ERO1 and 4HNE while males exhibited reduced PDI and Prdx4 paired with elevated BiP. EN460 attenuated cardiac and renal dysfunction and lowered LV ERO1/4HNE in females, but not males. IRE1C148S mitigated cardiac dysfunction in males and restore renal indices in both sexes. ConclusionsnPTX-EAE causes clinically relevant, sex-specific cardiorenal dysfunction linked to distinct ER stress/UPR alterations. ERO1 inhibition protects females, whereas enhanced IRE1 activity protects males and kidneys across sexes, supporting sex-specific ER stress-targeted therapies for MS-associated cardiorenal disease.

molecular biology↗