STAT3 in the dorsal raphe gates behavioural reactivity and regulates gene networks associated with psychopathology

Quantitative proteomics of the miR-301a/SOCS3/STAT3 axis reveals underlying autism and anxiety-like behavior

Autism is a widespread neurodevelopmental disorder. Although the research on autism spectrum disorders has been increasing in the past decade, there is still no specific answer to its mechanism of action and treatment. As a pro-inflammatory microRNA, miR-301a is abnormally expressed in various psychiatric diseases including autism. Here, we show that miR-301a deletion and inhibition exhibited two distinct abnormal behavioral phenotypes in mice. We observed that miR-301a deletion in mice impaired learning/memory, and enhanced anxiety. On the contrary, miR-301a inhibition effectively reduced the maternal immune activation (MIA)-induced autism-like behaviors in mice. We further demonstrated that miR-301a bound to the 3'UTR region of the SOCS3, and that inhibition of miR-301a led to the upregulation of SOCS3 in hippocampus. The last result in the reduction of the inflammatory response by inhibiting phosphorylation of AKT and STAT3, and the expression level of IL-17A in poly(I:C)-induced autism-like features in mice. The obtained data revealed the miR-301a as a critical participant in partial behavior phenotypes, which may exhibit a divergent role between gene knockout and knockdown. Our findings ascertain that miR-301a negatively regulates SOCS3 in MIA-induced autism in mice and could present a new therapeutic target for ameliorating the behavioral abnormalities of autism.

MicroRNA-124 negatively regulates STAT3 to alleviate hypoxic-ischemic brain damage by inhibiting oxidative stress

MicroRNA-124 (miR-124) is implicated in various neurological diseases; however, its significance in hypoxic-ischaemic brain damage (HIBD) remains unclear. This study aimed to elucidate the underlying pathophysiological mechanisms of miR-124 in HIBD. In our study performed on oxygen-glucose deprivation followed by reperfusion (OGD)/R-induced primary cortical neurons, a substantial reduction in miR-124 was observed. Furthermore, the upregulation of miR-124 significantly mitigated oxidative stress, apoptosis, and mitochondrial impairment. We demonstrated that miR-124 interacts with the signal transducer and activator of transcription 3 (STAT3) to exert its biological function using the dual-luciferase reporter gene assay. As the duration of OGD increased, miR-124 exhibited a negative correlation with STAT3. STAT3 overexpression notably attenuated the protective effects of miR-124 mimics, while knockdown of STAT3 reversed the adverse effects of the miR-124 inhibitor. Subsequently, we conducted an HIBD model in rats. In vivo experiments, miR-124 overexpression attenuated cerebral infarction volume, cerebral edema, apoptosis, oxidative stress, and improved neurological function recovery in HIBD rats. In summary, the neuroprotective effects of the miR-124/STAT3 axis were confirmed in the HIBD model. MiR-124 may serve as a potential biomarker with significant therapeutic implications for HIBD.

Neuronal pyroptosis mediated by STAT3 in early brain injury after subarachnoid hemorrhage

Neuroinflammation induced by early brain injury (EBI) seriously affects the prognosis of patients after subarachnoid hemorrhage (SAH). Pyroptosis can aggravate inflammatory injury by promoting the secretion of inflammatory cytokines. Meanwhile, STAT3 plays a critical role in the inflammatory response of EBI after SAH. However, whether it plays a pyroptotic role in SAH is mainly unknown. This study aimed to explore the mechanism of STAT3 in pyroptosis in EBI after SAH. C57BL/6J mice were used to establish the SAH model. Brain tissues were collected at different time points for q-RT-PCR and western blot to detect the expression level of STAT3. After intracerebroventricular injection of STAT3 inhibitor S3I-201, they were divided into sham, SAH, SAH + Vehicle, and SAH + S3I-201. Then, the SAH grade, cerebral edema content, blood-brain barrier (BBB) damage, and neurological scores of mice in each group were detected. qRT-PCR and western blot were used to detect related genes and proteins, and enzyme-linked immunosorbent assay (ELISA) was used to detect the expression levels of IL-18 and IL-1β. Immunofluorescence staining was used to observe the expression level of proteins. At the same time, S3I-201 was added to the primary neuron cells of the culture medium containing OxyHb to simulate the in vitro experiment, and the relevant indicators consistent with the in vivo experiment were detected. The expression of STAT3 was upregulated after SAH. Inhibition of STAT3 with S3I-201 attenuated neurological deficits, cerebral edema, and BBB damage after SAH. In addition, S3I-201 can also reduce the expression of pyroptosis-related inflammasomes such as GSDMD, NLRP3, Caspase 1, and AIM2 after SAH and the neurological damage caused by IL-18 and IL-1β. Further studies have shown that STAT3 regulates pyroptosis by promoting the nuclear translocation of NF-κB p65. Our finding demonstrated that STAT3 regulates neuronal pyroptosis in EBI after SAH. Inhibition of STAT3 may be a potential target to attenuate the damage that triggers neuroinflammation after SAH.

JAK-STAT signaling in inflammation and stress-related diseases: implications for therapeutic interventions

The Janus kinase-signal transducer and transcription activator pathway (JAK-STAT) serves as a cornerstone in cellular signaling, regulating physiological and pathological processes such as inflammation and stress. Dysregulation in this pathway can lead to severe immunodeficiencies and malignancies, and its role extends to neurotransduction and pro-inflammatory signaling mechanisms. Although JAK inhibitors (Jakinibs) have successfully treated immunological and inflammatory disorders, their application has generally been limited to diseases with similar pathogenic features. Despite the modest expression of JAK-STAT in the CNS, it is crucial for functions in the cortex, hippocampus, and cerebellum, making it relevant in conditions like Parkinson's disease and other neuroinflammatory disorders. Furthermore, the influence of the pathway on serotonin receptors and phospholipase C has implications for stress and mood disorders. This review expands the understanding of JAK-STAT, moving beyond traditional immunological contexts to explore its role in stress-related disorders and CNS function. Recent findings, such as the effectiveness of Jakinibs in chronic conditions such as rheumatoid arthritis, expand their therapeutic applicability. Advances in isoform-specific inhibitors, including filgotinib and upadacitinib, promise greater specificity with fewer off-target effects. Combination therapies, involving Jakinibs and monoclonal antibodies, aiming to enhance therapeutic specificity and efficacy also give great hope. Overall, this review bridges the gap between basic science and clinical application, elucidating the complex influence of the JAK-STAT pathway on human health and guiding future interventions.

Blood transcriptome analysis suggests an indirect molecular association of early life adversities and adult social anxiety disorder by immune-related signal transduction

Social anxiety disorder (SAD) is a psychiatric disorder characterized by severe fear in social situations and avoidance of these. Multiple genetic as well as environmental factors contribute to the etiopathology of SAD. One of the main risk factors for SAD is stress, especially during early periods of life (early life adversity; ELA). ELA leads to structural and regulatory alterations contributing to disease vulnerability. This includes the dysregulation of the immune response. However, the molecular link between ELA and the risk for SAD in adulthood remains largely unclear. Evidence is emerging that long-lasting changes of gene expression patterns play an important role in the biological mechanisms linking ELA and SAD. Therefore, we conducted a transcriptome study of SAD and ELA performing RNA sequencing in peripheral blood samples. Analyzing differential gene expression between individuals suffering from SAD with high or low levels of ELA and healthy individuals with high or low levels of ELA, 13 significantly differentially expressed genes (DEGs) were identified with respect to SAD while no significant differences in expression were identified with respect to ELA. The most significantly expressed gene was MAPK3 (p = 0.003) being upregulated in the SAD group compared to control individuals. In contrary, weighted gene co-expression network analysis (WGCNA) identified only modules significantly associated with ELA (p ≤ 0.05), not with SAD. Furthermore, analyzing interaction networks of the genes from the ELA-associated modules and the SAD-related MAPK3 revealed complex interactions of those genes. Gene functional enrichment analyses indicate a role of signal transduction pathways as well as inflammatory responses supporting an involvement of the immune system in the association of ELA and SAD. In conclusion, we did not identify a direct molecular link between ELA and adult SAD by transcriptional changes. However, our data indicate an indirect association of ELA and SAD mediated by the interaction of genes involved in immune-related signal transduction.

The metabolic regulator USF-1 is involved in the control of affective behaviour in mice

Epidemiological studies indicate a bidirectional association between metabolic disturbances, including obesity and related pathological states, and mood disorders, most prominently major depression. However, the biological mechanisms mediating the comorbid relationship between the deranged metabolic and mood states remain incompletely understood. Here, we tested the hypothesis that the enhanced activation of brown fat tissue (BAT), known to beneficially regulate obesity and accompanying dysfunctional metabolic states, is also paralleled by an alteration of affective behaviour. We used upstream stimulatory factor 1 (USF-1) knock-out (KO) mice as a genetic model of constitutively activated BAT and positive cardiometabolic traits and found a reduction of depression-like and anxiety-like behaviours associated with USF-1 deficiency. Surgical removal of interscapular BAT did not impact the behavioural phenotype of USF-1 KO mice. Further, the absence of USF-1 did not lead to alterations of adult hippocampal neural progenitor cell proliferation, differentiation, or survival. RNA-seq analysis characterised the molecular signature of USF-1 deficiency in the hippocampus and revealed a significant increase in the expression of several members of the X-linked lymphocyte-regulated (xlr) genes, including xlr3b and xlr4b. Xlr genes are the mouse orthologues of the human FAM9 gene family and are implicated in the regulation of dendritic branching, dendritic spine number and morphology. The transcriptional changes were associated with morphological alterations in hippocampal neurons, manifested in reduced dendritic length and complexity in USF-1 KO mice. Collectively these data suggest that the metabolic regulator USF-1 is involved in the control of affective behaviour in mice and that this modulation of mood states is unrelated to USF-1-dependent BAT activation, but reflected in structural changes in the brain.

Effects of Changyu Daotan Decoction on Depression via Restoration of Mice Hippocampus and Alteration of Expression of Relevant Neurotrophic Factors

Depression, a sort of common psychological disorder, is a serious hazard to people’s health and social progress. Conventional clinical means for this disorder nowadays are mostly chemical medicine treatments accompanied by psychological counseling. Chinese application of using TCM to treat mental diseases like depression could be traced from hundreds of years ago, in comparison to the long-term depression course and the chemical medicine administration demerits like side effects and resistance, traditional Chinese medicines are milder, more lasting, stable and are the optimal choice for perennial depression treatment. This study was committed to making a comprehensive investigation of Changyu Daotan Decoction’s efficacy in the depression mice model, and it turned out that the Changyu Daotan Decoction was capable of restoring the hippocampus of the depression mice and altering the expressions of neurotrophic factors (the expressions of β-Catenin, cyclin D1 and in GSK-3β BDNF, GFAP, NGF, and Wnt signaling pathways). Results of metabonomics analysis showed that the contents of GABA, His, Tyr, Trp, PA, and 5-HIAA in the mice of the Changyu Daotan Decoction group were restored after administration and showed a conspicuous relevance with the metabolic.

Slitrk2 deficiency causes hyperactivity with altered vestibular function and serotonergic dysregulation

SLITRK2 encodes a transmembrane protein that modulates neurite outgrowth and synaptic activities and is implicated in bipolar disorder. Here, we addressed its physiological roles in mice. In the brain, the Slitrk2 protein was strongly detected in the hippocampus, vestibulocerebellum, and precerebellar nuclei—the vestibular-cerebellar-brainstem neural network including pontine gray and tegmental reticular nucleus. Slitrk2 knockout (KO) mice exhibited increased locomotor activity in novel environments, antidepressant-like behaviors, enhanced vestibular function, and increased plasticity at mossy fiber–CA3 synapses with reduced sensitivity to serotonin. A serotonin metabolite was increased in the hippocampus and amygdala, and serotonergic neurons in the raphe nuclei were decreased in Slitrk2 KO mice. When KO mice were treated with methylphenidate, lithium, or fluoxetine, the mood stabilizer lithium showed a genotype-dependent effect. Taken together, Slitrk2 deficiency causes aberrant neural network activity, synaptic integrity, vestibular function, and serotonergic function, providing molecular-neurophysiological insight into the brain dysregulation in bipolar disorders.

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Slitrk2 KO mice showed antidepressant-like behaviors and enhanced vestibular function

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Mossy fiber-CA3 synaptic sensitivity to serotonin was reduced in Slitrk2 KO mice

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Serotonin metabolite was increased in hippocampus and amygdala of Slitrk2 KO mice

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Numbers of serotonergic neurons in raphe nuclei were decreased in Slitrk2 KO mice