IntroductionDepression disproportionately affects women, yet the molecular adaptations underlying stress susceptibility in the female brain remain poorly understood. The nucleus accumbens (NAc) is a key brain region regulating reward, motivation and affective behavior and is strongly implicated in stress-related disorders. This study aimed to characterize proteome-wide molecular adaptations in the female NAc following chronic social stress.MethodsWe used a recently developed female chronic social defeat stress (femCSDS) paradigm and performed label-free quantitative proteomic profiling of the NAc. Differentially expressed proteins were analyzed using Ingenuity Pathway Analysis (IPA), STRING, Metascape, SynGO and transcription factor enrichment approaches to identify affected pathways, molecular networks and regulatory programs.ResultsProteomic profiling identified 851 significantly dysregulated proteins, comprising 481 downregulated and 370 upregulated proteins, indicating extensive molecular remodeling following chronic social stress. Downregulated proteins were strongly enriched for mitochondrial respiration, oxidative phosphorylation, ATP synthesis, mitochondrial quality-control pathways and metabolic processes. Network analyses identified ATP synthase subunits, respiratory chain components and Cullin-family proteins as central hubs within a highly interconnected mitochondrial-proteostatic circuit. In contrast, upregulated proteins preferentially clustered within synaptogenesis, glutamatergic signaling, endocytosis, vesicle trafficking and synaptic organization pathways. Key hub proteins included SYNJ1, DNM1, BIN1, AP2M1, EPN2 and EPN3. Disease enrichment analyses linked the proteomic signature to neurological, neurodevelopmental and mitochondrial disorders. Transcription factor enrichment and upstream regulator predictions highlighted regulatory programs involving ARNT2, ESRRA, NFE2L2, PIN1, CAMTA1 and MYT1L.DiscussionThis study provides a comprehensive proteomic profile of the female NAc following female chronic social defeat stress (femCSDS). Our analysis indicates that femCSDS may induce widespread molecular remodeling in the female NAc characterized by mitochondrial dysfunction, reduced energetic capacity and altered metabolic regulation alongside enhanced synaptic remodeling. These results provide insight into female-specific stress adaptations and identify molecular pathways that may contribute to depression-related behavioral outcomes and represent potential targets for future investigation.

IntroductionVicarious trauma, the psychological distress from witnessing others’ suffering, is an increasingly recognized precursor to depression and anxiety. However, the underlying neurobiological mechanisms remain poorly understood and appear to be sex-dependent. This study investigated the behavioral, physiological, and molecular consequences of purely psychological stress using a novel rodent model of vicarious learned helplessness (VLH).MethodsMale and female C57BL/6J mice were used to establish VLH paradigm. Observer mice witnessed conspecifics receiving inescapable foot shocks through a partitioned chamber allowing multisensory interaction. Following 7 days of conditioning, behavioral assays assessed anxiety and depressive symptoms. Prefrontal cortex tissue was analyzed using RT-qPCR and immunoblotting to identify molecular alterations.ResultsVicarious stress induced depression phenotype in both sexes, characterized by active avoidance deficits, anhedonia and anxiety, comparable to direct physical trauma. Physiological assessments revealed hypothalamic-pituitary-adrenal (HPA) axis hyperactivity with elevated plasma corticosterone in both sexes. While molecular analysis showed shared downregulation of metabotropic glutamate receptor 2 (mGluR2) and elevated Il6 mRNA in the prefrontal cortex, distinct sexual dimorphism emerged. Males displayed specific deficits in neurotrophic support (Bdnf and BDNF) and glucocorticoid signaling (Nr3c1), whereas females exhibited impairments in social bonding pathways (Oxtr) and postsynaptic scaffolding proteins (PSD-95 and SHANK3).DiscussionVicarious trauma is sufficient to drive depression-like pathology through distinct molecular trajectories in males and females. These findings are suggestive of the critical necessity for sex-specific therapeutic strategies when treating trauma-related psychiatric disorders.

Depression shows significant sex differences in prevalence and neurobiological underpinnings, yet preclinical research investigating the pathophysiology of depression and the efficacy of antidepressants has predominantly relied on male models. Here, we establish a novel female chronic social defeat stress paradigm by leveraging the natural aggression of parous CD1 females, co-housed with castrated males to induce aggression while eliminating confounding sexual behaviors and without hormonal or surgical manipulations. Selected aggressive females reliably displayed offensive behaviors toward C57BL/6NCrl intruders across repeated encounters. Defeated female mice exhibited pronounced depression-like behaviors, including social withdrawal, anhedonia, behavioral despair, and elevated anxiety-like responses. Biochemical analysis revealed elevated glutamate levels in Nucleus Accumbens (NAc) and caudate putamen (CPu). Alterations in EAAT1, GRIN2B, and Neurabin expression were observed in CPu, indicating excitotoxic stress and compromised synaptic integrity. Given the extensive literature on male CSDS and its established pathophysiology, we aimed and successfully developed female-specific replica model of traditional male CSDS, enabling direct comparison and elucidation of sex differences in depression pathophysiology.

Depression is a debilitating neuropsychiatric disorder, and the failure of many antidepressants in clinical trials reflects the limited predictive validity of preclinical models. Therefore, a comparative evaluation of animal models that recapitulate the behavioral and molecular features of depression is essential for improving translational relevance. This study evaluated the utility of two chronic stress paradigms in zebrafish for modeling depression-like states. A modified Chronic Stress model termed Chronic Aggression Stress (CAgS) was developed and compared with the established Chronic Unpredictable Stress (CUS) model. In the CAgS paradigm, zebrafish were subjected to daily encounters with an aggressive cichlid for five days, while the CUS paradigm involved ten distinct stressors administered unpredictably twice daily for 10 days. Behavioral outcomes were assessed using the novel tank test, scototaxis, and threat response test. Molecular changes were examined by RT-qPCR, western blotting, and immunofluorescence. Both stress models induced robust depression-like phenotypes in adult zebrafish. CAgS produced consistent behavioral deficits, including reduced locomotion, increased anxiety-like behavior, and enhanced passive defensive responses across sexes, whereas CUS elicited divergent behavioral trajectories. At the molecular level, CAgS triggered a pronounced pro-inflammatory state characterized by elevated microglial activation and disrupted neurotrophic signaling. In contrast, CUS produced a more heterogeneous response, including sex-specific regulation of inflammatory cytokines and neurotrophic pathways. Both stress paradigms also showed astroglial activation and altered cellular proliferation. These findings demonstrate that both CAgS and CUS paradigms induce depressive-like phenotypes in zebrafish, with CUS uniquely revealing sex-specific behavioral and molecular alterations, highlighting their complementary utility for investigating depressive pathophysiology.

The sex differences in major depressive disorder are well-established, with women showing greater vulnerability and more severe symptoms than men. However, the underlying molecular mechanisms driving this disparity remain unclear. Chronic stress is a key trigger for depressive disorders, and the significant impact of stress on the neurogenic hippocampal dentate gyrus (DG) may be a critical factor in this link. The present study examined sexspecific responses to chronic stress in mice. Females exhibited depressive symptoms, including anhedonia and despair, while males showed resilience. Interestingly, upregulated corticotropin-releasing hormone receptors in the DG were observed in both sexes. However, the observation of impaired early adult neurogenesis markers and reduced dendritic spine density in the dentate gyrus of stress-induced depressive female mice exclusively suggested a potential sex-specific difference in resilience, with males exhibiting a greater capacity to withstand the negative consequences of chronic stress. This led us to use a proteomic approach to investigate the molecular basis of sex-specific responses to chronic stress in the hippocampal dentate gyrus of male and female mice. The present study identified 20 proteins that were differentially regulated, associated with key cellular functions, including cell cycle regulation, Hippo signalling, PI3K/AKT signalling, and axon guidance. Notably, only a subset of 14-3-3 family proteins exhibited contrasting expression patterns between stressed male and female mice, suggesting a potential role in mediating stress resilience in males. Overall, the findings highlight sex-specific differences in the hippocampal dentate gyrus's response to chronic stress and shed light on the molecular mechanisms underlying sex-based differences in stress susceptibility.

Peripheral nervous system injury (PNI) is a leading cause of long-term disability worldwide, with traumatic damage to major nerves such as the sciatic nerve, facial nerve, and brachial plexus severely impairing motor function, reducing life expectancy, and predisposing to mood disorders, thereby imposing a substantial socioeconomic burden. Effective therapies to limit PNI-induced neural damage, particularly in sciatic nerve injury (SNI), remain inadequate, largely due to an incomplete understanding of the underlying molecular mechanisms. To evaluate the efficacy of the CNS-active Spiro tricyclic compound IM-1725-RS-109a in improving motor deficits and modulating injury-related molecular markers in a mouse model of SNI. Sciatic nerve injury was induced in C57BL/6NCrl mice using a standardized crush-force technique. The spiro compound IM-1725-RS-109a, previously shown to be effective in an ischemic stroke mouse model, was administered intraperitoneally at a daily dose of 5 mg/kg for 5 days following injury. Treatment with IM-1725-RS-109a significantly restored motor behavioral performance in OFT, rotarod, and pole tests in SNI mice compared with SNI group controls. Marked differences were observed between groups receiving treatment initiated at different post-injury time points. qRT-PCR and Western Blot analysis revealed significant increases in neurogenesis and reductions in inflammation in the treatment groups. IM-1725-RS-109a confers functional and molecular neuroprotection in a mouse model of sciatic nerve injury, supporting the peripheral neuroprotective and anti-inflammatory potential of CNS-active spiro tricyclic compounds. These findings suggest that the compound may be a promising candidate for further development as a therapeutic strategy for PNI.

Cerebral ischemic preconditioning offers a promising strategy to enhance resilience to severe ischemic insults. Unilateral common carotid artery occlusion (UCCAo) is a valuable model to simulate chronic cerebral hypoperfusion (CCH). This study explored UCCAo-induced CCH as a preconditioning stimulus to induce ischemic tolerance against transient global cerebral ischemia (tGCI) induced by bilateral common carotid artery occlusion (BCCAo) in both male and female mice. We evaluated the effects of CCH preconditioning on neuroprotection and recovery through behavioral, histopathological, and molecular analyses. Laser Doppler Imaging (LDI) confirmed significant cerebral hypoperfusion post-UCCAo. Preconditioning reduced mortality rates at days 1 and 7 post-surgery as compared to BCCAo, suggesting its neuroprotective potential. Neurodeficit scoring demonstrated significant protection in preconditioned animals with recovery aligning closer to sham controls. Behavioral assays revealed improved motor and cognitive outcomes in preconditioned groups, with sex-specific differences evident in recovery dynamics. Molecular analyses indicated reduced reactive astrocyte (GFAP) and microglial (IBA1) activation in preconditioned animals, reflecting controlled glial responses. Sex-dependent variations in markers of hypoxia (Hif1a), autophagy (Becn1), and neurogenesis (Sox2) highlighted neuroadaptive and cellular influences on ischemic resilience. Preconditioning enhanced synaptic plasticity by upregulating PSD-95, synaptophysin and BDNF levels. In addition, preconditioning increased VEGF expression in blood serum reflecting vascular remodeling and neuroprotective angiogenesis. This study positions UCCAo-induced CCH as a reliable model for exploring ischemic tolerance mechanisms to advance therapeutic strategies for mitigating the effects of ischemic stroke.

Major Depressive Disorder (MDD) remains a leading cause of disability worldwide, perpetuated by an incomplete understanding of its pathophysiology and the limited efficacy of conventional antidepressants. Historically, research has focused on neuron-centric models, particularly the monoamine hypothesis. However, the field is now recognizing the critical role of glial cells such as astrocytes, microglia, and oligodendrocytes, establishing them as key contributors to the molecular basis of depression. Rather than serving solely supportive roles, these cells actively modulate neuroinflammation, synaptic plasticity, neurotransmitter homeostasis, and metabolic regulation, processes disrupted in MDD. We discuss how stress-induced epigenetic modifications such as histone acetylation, methylation, and DNA methylation are linked to alterations in astrocytic glutamate transport, microglial inflammatory states, and oligodendrocyte-mediated myelination. Special emphasis is placed on the concept of glial transcriptional plasticity, whereby environmental adversity induces durable and cell type specific gene expression changes that underlie neuroinflammation, excitatory–inhibitory imbalance, and white matter deficits observed in MDD. By integrating findings from postmortem human tissue, single-cell omics, and stress-based animal models, this review highlights converging molecular mechanisms linking stress to glial dysfunction. We further outline how targeting glial transcriptional regulators may provide new therapeutic avenues beyond conventional monoaminergic approaches.

Major depressive disorder (MDD) results from repeated and constant exposure to stress over prolonged periods. The highly variable response to stress and the low heritability suggests that MDD has a strong epigenetic basis. Studies show global dysregulation of histone modifications in both susceptible and resilient animals after chronic stress suggesting involvement of epigenetics in stress response in the brain. Given that the hippocampus and dentate gyrus (DG) show epigenetic changes in neurogenesis in Rodent models of stress that is known to be highly affected in MDD, we hypothesized that epigenetic changes might be involved in the advent of depressive phenotype during the progressive stress paradigm. To study the stress progression into the depression-like phenotype at the molecular level, we designed a novel progressive social defeat stress (PSDS) paradigm based on the popular chronic social defeat stress (CSDS) paradigm but involving only 5 days of defeat stress. Our molecular studies revealed consistent downregulation of H3K9me2 marks in the hippocampus and DG after the 4th day of stress while H3K27me2 showed an early upregulation in the hippocampus and a late downregulation after the 5th day of stress in the DG. In parallel, an early increase in phf8 and phf2 in hippocampus and DG, respectively, was observed. These findings of variable changes like repressive histone methylation marks and expression of corresponding demethylase genes after different durations of defeat stress, led to better understanding of the important role epigenetics play in stress progression into depression at molecular level in establishing resilient and susceptible phenotypes.

Vicarious trauma, a form of emotional stress experienced by observing the suffering of others has gained prominence as a major contributor to depression and other stress-related disorders. Traditional animal models of depression such as Chronic Social Defeat Stress (CSDS) focus on physical stressors but fail to replicate the psychological dimensions of vicarious trauma. The Vicarious Social Defeat Stress (VSDS) model fills this gap by inducing emotional stress without physical injury. This enables us to investigate the neural, behavioral and molecular mechanisms unique to emotional stress-induced depression. Studies have shown differential pharmacological efficacy of antidepressants in emotional versus physical stress, emphasizing the necessity of models like VSDS to investigate these variations comprehensively. This review integrates insights from VSDS studies focusing on dysregulations in the hypothalamic pituitary adrenal (HPA) axis, neuroendocrine modalities, neuroinflammatory processes mediated by IL-6, IL-1β and CRH-BDNF signaling. We explore diverse behavioral strategies for VSDS modeling, emphasizing its utility in capturing the complex neurobiological and behavioral outcomes of vicarious stress. Sex-specific differences in vicarious stress have also been investigated. Additionally, we address limitations of current models, specifically their male-centric design and propose future directions, including the development of female-specific paradigms and enhancing ecological validity. By integrating insights into behavioral outcomes, sex differences, resilience and susceptibility, this review positions VSDS as a crucial model for enhancing our understanding of emotional stress and its implications in neuropsychiatric disorders.

Depression shows significant sex differences in prevalence and neurobiological underpinnings, yet preclinical research investigating the pathophysiology of depression and the efficacy of antidepressants has predominantly relied on male models. Here, we establish a novel female chronic social defeat stress paradigm by leveraging the natural aggression of parous CD1 females, co-housed with castrated males to induce aggression while eliminating confounding sexual behaviors and without hormonal or surgical manipulations. Selected aggressive females reliably displayed offensive behaviors toward C57BL/6NCrl intruders across repeated encounters. Defeated female mice exhibited pronounced depression-like behaviors, including social withdrawal, anhedonia, behavioral despair, and elevated anxiety-like responses. Biochemical analysis revealed elevated glutamate levels in Nucleus Accumbens (NAc) and caudate putamen (CPu). Alterations in EAAT1, GRIN2B, and Neurabin expression were observed in CPu, indicating excitotoxic stress and compromised synaptic integrity. Label free Quantitative MS-MS analysis of NAc revealed 1194 significantly dysregulated proteins. Ingenuity Pathway Analysis highlighted canonical pathway disruptions in synaptogenesis signaling pathway and glutamate signaling pathway. Disease and function analysis revealed enrichment in neuroinflammation, synaptic dysfunction, and mitochondrial dysfunction. Given the extensive literature on male CSDS and its established pathophysiology, we aimed and successfully developed female-specific replica model of traditional male CSDS, enabling direct comparison and elucidation of sex differences in depression pathophysiology. ### Competing Interest Statement The authors have declared no competing interest. SERB-POWER, SPF/2021/000045

Metabolic disorders (MetDs), driven mostly by lifestyle changes are growing at an alarming rate, and have cardiovascular and cerebrovascular consequences, eventually leading to various neuropsychiatric disorders. Considering a dearth of studies, we modeled MetDs-like conditions in C57BL/6 Ncrl mice on prolonged 60

The internal carotid artery occlusion (ICAO) model in mice replicates a clinically relevant subtype of stroke (mild to moderate ischemic stroke). The ICAO model represents a significant advancement in preclinical stroke research, providing a more accurate representation of human strokes caused by internal carotid artery occlusion. This model has facilitated novel insights into epigenetic modifications following stroke, specifically the dynamics of histone lysine methylation and demethylation, which are crucial in ischemia-induced brain damage and recovery. In contrast to the widely used middle cerebral artery occlusion (MCAO) model, which primarily induces extensive cortical damage, the ICAO model more precisely mimics the striatal and hippocampal injury seen in these stroke cases. Here, we describe the establishment and utilization of the ICAO model in adult CD1 mice, highlighting its reliability and reproducibility in inducing mild to moderate ischemic injury. Our method involves a temporary occlusion of the internal carotid artery for 90 min, followed by reperfusion, leading to localized neural damage. This article details the surgical procedure for inducing ICAO in mice, followed by methods for characterizing the resulting ischemia. These methods include laser doppler perfusion imaging and neurobehavioral assessments, such as neurological deficit scoring and motor function tests. Additionally, the model also emphasizes the importance of considering sex-specific differences in the response to ICAO. This model's ability to yield reproducible and localized neural damage makes it a valuable tool for studying stroke pathophysiology and evaluating potential therapeutic interventions. © 2025 Wiley Periodicals LLC. Basic Protocol 1: Detailed surgical procedure for inducing internal carotid artery occlusion Basic Protocol 2: Laser doppler perfusion imaging Basic protocol 3: Neurobehavioral assessments.

This study investigates the influence of sex on region-specific neural vulnerability following global cerebral ischemia using a Bilateral Common Carotid Artery Occlusion (BCCAo) mouse model that mimics severe ischemic brain stroke condition in humans. Comprehensive behavioral assessments, neuropathological analyses, and molecular profiling were conducted across multiple time points post-ischemia in male and female CD1 mice. Both sexes exhibited early motor deficits, cortical-striatal mitochondrial dysfunction, inflammation, and cell death at day 1, with gradual behavioral recovery. However, the hippocampus demonstrated a clear sex-specific divergence: males exhibited delayed yet prolonged inflammation, apoptotic cell death, and increased autophagy/mitophagy activity, while females were largely protected despite hypoxic and inflammatory gene expression. Molecular assays revealed prolonged upregulation of hypoxia-inducible factor 1α (HIF-1α), IL-1β, IL-6, TNF-α, and apoptotic markers in males, especially in the hippocampus, alongside increased expression of autophagy (Beclin-1, LC3-II, ATG7) and mitophagy (PINK1, BNIP3L) regulators and a shift in mitochondrial dynamics favoring fission.

Metabolic disorders (MetDs)are growing at an alarming rate because of lifestyle changes and have cardiovascular and cerebrovascular consequences, in the long run resulting in neuropsychiatric disorders. However, there is a dearth of molecular studies that deal with the underlying neural mechanisms using relevant animal models of MetDs-induced neurological and psychiatric disorders. We modeled MetDs-like condition in C57BL/6 Ncrl mice by feeding a 60% high fructose diet (Hfr) for 56 weeks. Significant changes were observed in various MetD-related physiological parameters between the Hfr diet and the control group except for glucose intolerance. Prolong Hfr diet induced some of the metabolic disorder like phenotype including aging except type-2 diabetes. But 10 days of chronic unpredictable mild stress (CUMS) paradigm induced mild insulin intolerance in oral glucose tolerance test. Further the animals were found to develop neurological and cognitive impairment and major depressive disorder like phenotype. Transcriptomic analysis led to uncover underlying molecular changes into the prefrontal cortex region of mice. The pattern of differentially expressed genes (DEGs) was strikingly different in the Hfr group compared to the Ctrl group, thus correlating the phenotype, i.e. MetD-induced mood and cognitive disorders. Pathway analysis of the DEGs indicated perturbations in cellular metabolism, inflammation, innate immunity, neurogenesis, vasculogenesis, ion channels, and neuronal signaling. In addition, altered epigenetic regulators appear to mediate the stress-induced precipitation of metabolic and neuropsychiatric disorders. The outcome of our study supports the hypothesis of disease susceptibility due to lifestyle changes involving a high-calorie diet and chronic stress.

Critical limb ischemia (CLI) refers to a severe condition resulting from gradual obstruction in the supply of blood, oxygen, and nutrients to the limbs. The most promising clinical solution to CLI is therapeutic angiogenesis. This study explored the potency of pro-angiogenic terbium hydroxide nanorods (THNR) for treatment of CLI, with a major focus on their impact on ischemia-induced maladaptive alterations in endothelial cells as well as on vascularization in ischemic limbs. This study demonstrated that, in hypoxia-exposed endothelial cells, THNR improve survival and promote proliferation, migration, restoration of nitric oxide production, and regulation of vascular permeability. Based on molecular studies, these attributes of THNR can be traced to the stimulation of PI3K/AKT/eNOS signaling pathways. Besides, Wnt/GSK-3β/β-catenin signaling pathways may also play a role in the therapeutic actions of THNR. Furthermore, in the murine model of CLI, THNR administration can integrally re-establish blood perfusion with concomitant reduction of muscle damage and inflammation. Additionally, improvement of locomotor activities and motor coordination in ischemic limbs in THNR treated mice is also evident. Overall, the study demonstrates that THNR have the potential to be developed as an efficacious and cost-effective alternative clinical therapy for CLI, using a nanomedicine approach.

Amyotrophic Lateral Sclerosis (ALS) is the most common, adult-onset, progressive motor neurodegenerative disorder that results in death within 3 years of the clinical diagnosis. Due to the clinicopathological heterogeneity, any reliable biomarkers for diagnosis or prognosis of ALS have not been identified till date. Moreover, the only three clinically approved treatments are not uniformly effective in slowing the disease progression. Over the last 15 years, there has been a rapid advancement in research on the complex pathomechanistic landscape of ALS that has opened up new avenues for successful clinical translation of targeted therapeutics. Multiple studies suggest that the age-dependent interaction of risk-associated genes with environmental factors and endogenous modifiers is critical to the multi-step process of ALS pathogenesis. In this review, we provide an updated discussion on the dysregulated cross-talk between intracellular homeostasis processes, the unique molecular networks across selectively vulnerable cell types, and the multisystemic nature of ALS pathomechanisms. Importantly, this work highlights the alteration in epigenetic and epitranscriptomic landscape due to gene-environment interactions, which have been largely overlooked in the context of ALS pathology. Finally, we suggest that precision medicine research in ALS will be largely benefitted from the stratification of patient groups based on the clinical phenotype, onset and progression, genome, exposome, and metabolic identities.