OBJECTIVES: The neurotoxicity of carbon monoxide (CO) to the central nervous system is a key pathogenesis of delayed encephalopathy after acute carbon monoxide poisoning (DEACMP). Our previous study found that retinoic acid (RA) can suppress the neurotoxic effects of CO. This study further explores, in vivo and in vitro, the molecular mechanisms by which RA alleviates CO-induced central nervous system damage. METHODS: A cytotoxic model was established using the mouse hippocampal neuronal cell line HT22 and primary oligodendrocytes exposed to CO, and a DEACMP animal model was established in adult Kunming mice. Cell viability and apoptosis of hippocampal neurons and oligodendrocytes were assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and Annexin V/propidium iodide (PI) double staining. The transcriptional and protein expression of each gene was detected using real-time fluorescence quantitative PCR (RT-qPCR) and Western blotting. Long noncoding RNA (lncRNA) SNHG15 and LINGO-1 were knocked down or overexpressed to observe changes in neurons and oligodendrocytes. In DEACMP mice, SNHG15 or LINGO-1 were knocked down to assess changes in central nervous tissue and downstream protein expression. RESULTS: RA at 10 and 20 μmol/L significantly reversed CO-induced apoptosis of hippocampal neurons and oligodendrocytes, downregulation of SNHG15 and LINGO-1, and upregulation of brain-derived neurotrophic factor (BDNF) and tyrosine kinase receptor B (TrkB) (all P<0.05). Overexpression of SNHG15 or LINGO-1 weakened the protective effect of RA against CO-induced cytotoxicity (all P<0.05). Knockdown of SNHG15 or LINGO-1 alleviated CO-induced apoptosis of hippocampal neurons and oligodendrocytes and upregulated BDNF and TrkB expression levels (all P<0.05). Experiments in DEACMP model mice showed that knockdown of SNHG15 or LINGO-1 mitigated central nervous system injury in DEACMP (all P<0.05). CONCLUSIONS RA alleviates CO-induced apoptosis of hippocampal neurons and oligodendrocytes, thereby reducing central nervous system injury and exerting neuroprotective effects. LncRNA SNHG15 and LINGO-1 are key molecules mediating RA-induced inhibition of neuronal apoptosis and are associated with the BDNF/TrkB pathway. These findings provide a theoretical framework for optimizing the clinical treatment of DEACMP and lay an experimental foundation for elucidating its molecular mechanisms.
Animals ; RNA, Long Noncoding/physiology* ; Brain-Derived Neurotrophic Factor/genetics* ; Carbon Monoxide Poisoning/complications* ; Mice ; Tretinoin/pharmacology* ; Nerve Tissue Proteins/metabolism* ; Membrane Proteins/metabolism* ; Apoptosis/drug effects* ; Hippocampus/cytology* ; Receptor, trkB/metabolism* ; Neurons/drug effects* ; Male ; Brain Diseases/etiology* ; Oligodendroglia/drug effects* ; Signal Transduction ; Cell Line

The relationship between gut microbiota and depressive disorder has become a research focus in recent years. Within the microbiota-gut-brain axis, the gut microbiota influences the onset and progression of depressive disorder primarily through the tryptophan metabolic pathway. Tryptophan, an essential amino acid in humans, is subject to dual regulation by intestinal microorganisms, which modulate its metabolic balance via inflammatory stimulation and microbial metabolite production. In depression, excessive activation of the kynurenine branch of tryptophan metabolism leads to the accumulation of proinflammatory and neurotoxic metabolites, thereby exacerbating neuroinflammation in the brain. Intervention studies indicate that the antidepressant-like effects of probiotics and traditional Chinese medicine are associated with remodeling of the gut microbiota, restoration of tryptophan metabolic balance, and alleviation of neuroinflammation. Furthermore, targeted inhibition of kynurenine 3-monooxygenase can mitigate neuroinflammation by regulating microglial activity, thus improving depressive-like behaviors. In summary, the metabolite-inflammation axis represents a central node in the interaction regulation between tryptophan metabolism and the microbiota-gut-brain axis. This provides a theoretical foundation for developing novel therapeutic strategies targeting depression through modulation of gut microbiota-mediated tryptophan metabolism.
Tryptophan/metabolism* ; Gastrointestinal Microbiome/physiology* ; Humans ; Depressive Disorder/microbiology* ; Probiotics/therapeutic use* ; Brain/metabolism* ; Kynurenine/metabolism* ; Metabolic Networks and Pathways ; Animals ; Medicine, Chinese Traditional

Exercise-induced analgesia (EIA) refers to the elevation of pain thresholds and reduction in sensitivity to noxious stimuli achieved through exercise training. As a non-pharmacological treatment strategy, exercise therapy has demonstrated positive effects on both acute and chronic pain. Increasing evidence indicates that modulation of glial cell activity is an important mechanism underlying analgesia. Spinal glial cells contribute to the development and maintenance of pathological pain by promoting pain signal transmission through inflammatory responses and synaptic remodeling. Exercise can differentially regulate microglia and astrocyte activity, inhibiting multiple inflammatory signaling pathways, such as P2X4/P2X7 purinergic receptors, brain-derived neurotrophic factor (BDNF)/phosphatidylinositol 3-kinase (PI3K)/mammalian target of rapamycin (mTOR), interleukin (IL)-6/Janus kinase (JAK) 2/signal transducer and activator of transcription 3 (STAT3), p38-mitogen-activated protein kinases (MAPK), and Toll-like receptor 4 (TLR4)/nuclear factor-kappa B (NF-κB), thereby reducing the release of pro-inflammatory cytokines, decreasing inflammatory and nociceptive hypersensitivity, and alleviating pathological pain. This review also summarized the effects of different exercise intensities, durations, and frequencies on glial cell responses in order to provide a theoretical foundation for optimizing exercise-based interventions for pathological pain conditions.
Humans ; Microglia/metabolism* ; Astrocytes/metabolism* ; Exercise/physiology* ; Signal Transduction ; Analgesia/methods* ; Spinal Cord/cytology* ; Exercise Therapy ; Pain Management/methods* ; Animals ; Brain-Derived Neurotrophic Factor/metabolism*

Patients with depression are more likely to have chronic gastrointestinal (GI) symptoms than the general population, but such symptoms are considered only somatic symptoms of depression and lack special attention. There is a chronic lack of appropriate diagnosis and effective treatment for patients with depression accompanied by GI symptoms, and studying the association between depression and GI disorders (GIDs) is extremely important for clinical management. There is growing evidence that depression is closely related to the microbiota present in the GI tract, and the microbiota-gut-brain axis (MGBA) is creating a new perspective on the association between depression and GIDs. Identifying and treating GIDs would provide a key opportunity to prevent episodes of depression and may also improve the outcome of refractory depression. Current studies on depression and the microbially related gut-brain axis (GBA) lack a focus on GI function. In this review, we combine preclinical and clinical evidence to summarize the roles of the microbially regulated GBA in emotions and GI function, and summarize potential therapeutic strategies to provide a reference for the study of the pathomechanism and treatment of depression in combination with GI symptoms.
Humans ; Gastrointestinal Microbiome/physiology* ; Depression/microbiology* ; Gastrointestinal Diseases/physiopathology* ; Brain ; Animals ; Brain-Gut Axis ; Gastrointestinal Tract/microbiology*

Inflammatory bowel disease (IBD) is an idiopathic intestinal inflammatory condition with chronic and relapsing manifestations and is characterized by a disturbance in the interplay between the intestinal microbiota, the gut, and the brain. The microbiota-gut-brain axis involves interactions among the nervous system, the neuroendocrine system, the gut microbiota, and the host immune system. Increasing published data indicate that psychological stress exacerbates the severity of IBD due to its negative effects on the microbiota-gut-brain axis, including alterations in the stress response of the hypothalamic-pituitary-adrenal (HPA) axis, the balance between the sympathetic nervous system and vagus nerves, the homeostasis of the intestinal flora and metabolites, and normal intestinal immunity and permeability. Although the current evidence is insufficient, psychotropic agents, psychotherapies, and interventions targeting the microbiota-gut-brain axis show the potential to improve symptoms and quality of life in IBD patients. Therefore, further studies that translate recent findings into therapeutic approaches that improve both physical and psychological well-being are needed.
Humans ; Inflammatory Bowel Diseases/metabolism* ; Stress, Psychological/microbiology* ; Gastrointestinal Microbiome/physiology* ; Brain/metabolism* ; Hypothalamo-Hypophyseal System ; Pituitary-Adrenal System ; Animals

Brain science is the frontier of modern science, and new advances have been made in brain-like designs and brain-computer interfaces to simulate or develop brain functions. However, given that the brain is hermetically sealed within the skull, exploration and deciphering of the brain structure and functions are limited. Growing evidence suggests that the gut is not just a digestive organ. It not only provides essential nutrients and electrolytes for brain neurodevelopment and the maintenance of brain function, but it also transmits external environmental and intestinal wall signals from the intestinal lumen to the central nervous system through multiple pathways to regulate brain activity, function, and structure. A variety of gut-brain interaction pathways have been identified, including neural pathways, neuroimmune signaling, endocrine pathways, and biochemical messengers produced by gut microbes. Gut microbes interact with food and the gut to modulate gut-brain communication. The gut's important role and potential in neurodevelopment, maintenance of normal function, and disease development make it an increasingly important area of research in brain science and neuropsychiatric disorders. The gut's unique role in brain functions and its accessibility for research (compared to direct brain studies) establish it as a critical gate to understanding the mysteries of brain science. Crucially, intestinal nutrients and microbes provide two unique keys to unlock this gate-enabling neural regulation and novel treatments for neuropsychiatric diseases.
Humans ; Brain/physiology* ; Animals ; Gastrointestinal Microbiome/physiology* ; Gastrointestinal Tract/microbiology*

Brain cancer remains among the most lethal malignancies worldwide, with approximately 321,476 new cases and 248,305 deaths reported globally in 2022. The treatment of malignant brain tumors presents substantial clinical challenges, primarily due to their resistance to standard therapeutic approaches. Despite decades of intensive research, effective treatment strategies for brain cancer are still lacking. Nuclear receptors (NRs), a superfamily of ligand-activated transcription factors, regulate a broad range of physiological processes including metabolism, immunity, stress response, reproduction, and cellular differentiation. Increasing evidence highlights the involvement of NRs in oncogenesis, with several members demonstrating altered expression and function in brain tumors. Aberrations in NR signaling, encompassing receptors such as androgen receptors, estrogen receptors, estrogen-related receptors, glucocorticoid receptors, NR subfamily 4 group A, NR subfamily 1 group D member 2, NR subfamily 5 group A member 2, NR subfamily 2 group C member 2, liver X receptors, peroxisome-proliferator activated receptors, progesterone receptors, retinoic acid receptors, NR subfamily 2 group E member 1, thyroid hormone receptors, vitamin D receptors, and retinoid X receptors, have been implicated in promoting hallmark malignant phenotypes, including enhanced survival, proliferation, invasion, migration, metastasis, and resistance to therapy. This review aims to explore the roles of key NRs in brain cancer, with an emphasis on their prognostic significance, and to evaluate the therapeutic potential of targeting these receptors using selective agonists or antagonists.
Humans ; Brain Neoplasms/drug therapy* ; Receptors, Cytoplasmic and Nuclear/metabolism* ; Animals ; Signal Transduction/physiology*

Hypoxic-ischemic brain damage (HIBD) is one of the main causes of disability in middle-aged and elderly people, as well as high mortality rates and long-term physical impairments in newborns. The pathological manifestations of HIBD include neuronal damage and loss of myelin sheaths. Tau protein is an important microtubule-associated protein in brain, exists in neurons and oligodendrocytes, and regulates various cellular activities such as cell differentiation and maturation, axonal transport, and maintenance of cellular cytoskeleton structure. Phosphorylation is a common chemical modification of Tau. In physiological condition, it maintains normal cell cytoskeleton and biological functions by regulating Tau structure and function. In pathological conditions, it leads to abnormal Tau phosphorylation and influences its structure and functions, resulting in Tauopathies. Studies have shown that brain hypoxia-ischemia could cause abnormal alteration in Tau phosphorylation, then participating in the pathological process of HIBD. Meanwhile, brain hypoxia-ischemia can induce oxidative stress and inflammation, and multiple Tau protein kinases are activated and involved in Tau abnormal phosphorylation. Therefore, exploring specific molecular mechanisms by which HIBD activates Tau protein kinases, and elucidating their relationship with abnormal Tau phosphorylation are crucial for future researches on HIBD related treatments. This review aims to focus on the mechanisms of the role of Tau phosphorylation in HIBD, and the potential relationships between Tau protein kinases and Tau phosphorylation, providing a basis for intervention and treatment of HIBD.
Humans ; tau Proteins/physiology* ; Phosphorylation ; Hypoxia-Ischemia, Brain/physiopathology* ; Animals ; Oxidative Stress

Intelligence encompasses various abilities, including logical reasoning, comprehension, self-awareness, learning, planning, creativity, and problem-solving. Extensive research and practical experience suggest that there are sex differences in intellectual development, with females typically maturing earlier than males. However, the key genes and molecular network mechanisms underlying these sex differences in intellectual development remain unclear. To date, Genome-Wide Association Studies (GWAS) have identified 507 genes that are significantly associated with intelligence. This study first analyzed RNA sequencing data from different stages of brain development (from BrainSpan), revealing that during the late embryonic stage, the average expression levels of intelligence-related genes are higher in males than in females, while the opposite is observed during puberty. This study further constructed interaction networks of intelligence-related genes with sex-differential expression in the brain, including the prenatal male network (HELP-M: intelligence genes with higher expression levels in prenatal males) and the pubertal female network (HELP-F: intelligence genes with higher expression levels in pubertal females). The findings indicate that the key genes in both networks are Ep300 and Ctnnb1. Specifically, Ep300 regulates the transcription of 53 genes in both HELP-M and HELP-F, while Ctnnb1 regulates the transcription of 45 genes. Ctnnb1 plays a more prominent role in HELP-M, while Ep300 is more crucial in HELP-F. Finally, this study conducted sequencing validation on rats at different developmental stages, and the results indicated that in the prefrontal cortex of female rats during adolescence, the expression levels of the intelligence genes in HELP-F, as well as key genes Ep300 and Ctnnb1, were higher than those in male rats. These genes were also involved in neurodevelopment-related biological processes. The findings reveal a sex-differentiated intelligence gene network and its key genes, which exhibit varying expression levels during the neurodevelopmental process.
Female ; Intelligence/physiology* ; Male ; Sex Characteristics ; Animals ; Brain/growth & development* ; E1A-Associated p300 Protein/physiology* ; beta Catenin/physiology* ; Transcriptome ; Rats ; Gene Expression Profiling ; Genome-Wide Association Study

The neurophysiological mechanisms by which exercise improves cognitive function have not been fully elucidated. A comprehensive and systematic review of current domestic and international neurophysiological evidence on exercise improving cognitive function was conducted from multiple perspectives. At the molecular level, exercise promotes nerve cell regeneration and synaptogenesis and maintains cellular development and homeostasis through the modulation of a variety of neurotrophic factors, receptor activity, neuropeptides, and monoamine neurotransmitters, and by decreasing the levels of inflammatory factors and other modulators of neuroplasticity. At the cellular level, exercise enhances neural activation and control and improves brain structure through nerve regeneration, synaptogenesis, improved glial cell function and angiogenesis. At the structural level of the brain, exercise promotes cognitive function by affecting white and gray matter volumes, neural activation and brain region connectivity, as well as increasing cerebral blood flow. This review elucidates how exercise improves the internal environment at the molecular level, promotes cell regeneration and functional differentiation, and enhances the brain structure and neural efficiency. It provides a comprehensive, multi-dimensional explanation of the neurophysiological mechanisms through which exercise promotes cognitive function.
Animals ; Humans ; Brain/physiology* ; Cognition/physiology* ; Exercise/physiology* ; Nerve Regeneration/physiology* ; Neuronal Plasticity/physiology*