Gut microbiota from NLRP3-deficient mice ameliorates depressive-like behaviors by regulating astrocyte dysfunction via circHIPK2

circHIPK2 promotes malignant progression of laryngeal squamous cell carcinoma through the miR-889-3p/MCTS1/IL-6 axis

Laryngeal squamous cell carcinoma (LSCC) is a common malignant tumor of the head and neck with a poor prognosis. The role of circRNAs in LSCC remains largely unknown. In this study, quantitative real-time PCR (qRT-PCR), Sanger sequencing and fluorescence in situ hybridization were undertaken to detect the expression, localization, and clinical significance of circHIPK2 in LSCC tissues and TU686 and TU212 cells. The functions of circHIPK2 in LSCC were explored through proliferation analysis, EdU staining, colony formation assay, wound healing assay, and Transwell assay. The regulatory mechanisms underpinning circHIPK2, miR-889-3p, and MCTS1 were investigated using luciferase assay, Western blotting, and qRT-PCR. We found that LSCC tissues and cells demonstrated high expression of circHIPK2 that was closely associated with the malignant progression and poor prognosis of LSCC. Knockdown of circHIPK2 inhibited the proliferation and migration of LSCC cells in vitro. Mechanistic studies showed that circHIPK2 competitively bound to miR-889-3p, elevated MCTS1 level, promoted IL-6 secretion, and ultimately accelerated the malignant progression of LSCC. In conclusion, an axis involving circHIPK2, miR-889-3p, MCTS1 and IL-6 regulates the malignant progression of LSCC. circHIPK2 expression may serve as a novel diagnostic and prognostic biomarker for LSCC.

NLRP3 in the dorsal raphe nucleus manipulates the depressive-like behaviors

Major depressive disorder is one of the most common psychiatric disorders, and the Nod-like receptor family pyrin domain containing 3 (NLRP3) inflammasome plays an important role in depression. Dorsal raphe nucleus (DRN), as the main origin of producing serotonin in the brain, is an important functional brain region in depressive disorders. However, the relationship between NLRP3 in the DRN and depression has not been clarified in previous studies. So, we focus on demonstrating the role of NLRP3 expressed in DRN in depression. In this study, the male C57BL/6 J mice were exposed to chronic unpredictable mild stimulation and the expression and cellular localization of NLRP3 in DRN were analyzed. Subsequently, the mice were treated with the NLRP3 inhibitor MCC950 to inhibit NLRP3 inflammasome, and the expression of NLRP3 was knocked down in certain cells within the DRN of NLRP3fl/fl mice to investigate the role of NLRP3 in regulating depressive phenotype. Compared with the control group, the expression of NLRP3 in DRN of CUMS group was significantly increased, especially in the microglia and neuron. Furthermore, treatment with the NLRP3 inhibitor induced a significant antidepressant effect, and the depressive phenotype of NLRP3fl/fl mice was rescued after knocking down NLRP3 in the microglia or neuron. In addition, the expression levels of related molecules in the NLRP3 inflammasome pathway were significantly higher in the CUMS group compared to the control group. These results illustrated that NLRP3 played an important role in regulating depressive phenotype in DRN, and suggested a new therapy target for depression.

Linking depression and neuroinflammation: Crosstalk between glial cells

The inflammatory hypothesis is one of the more widely accepted pathogenesis of depression. Glia plays an important immunomodulatory role in neuroinflammation, mediating interactions between the immune system and the central nervous system (CNS). Glial cell-driven neuroinflammation is not only an important pathological change in depression, but also a potential therapeutic target. This review discusses the association between depression and glial cell-induced neuroinflammation and elucidates the role of glial cell crosstalk in neuroinflammation. Firstly, we focus on the role of glial cells in neuroinflammation in depression and glial cell interactions; secondly, we categorize changes in different glial cells in animal models of depression and depressed patients, focusing on how glial cells mediate inflammatory responses and exacerbate depressive symptoms; Thirdly, we review how conventional and novel antidepressants affect the phenotype and function of glial cells, thereby exerting anti-inflammatory activity; finally, we discuss the role of the gut-brain axis in glial cell function and depression, and objectively analyze the problems that remain in current antidepressant therapy. This review aims to provide an objective analysis of how glial cell cross-talk may mediate neuroinflammation and thereby influence pathologic progression of depression. It is concluded that a novel therapeutic strategy may be to ameliorate glial cell-mediated inflammatory responses.

Gut microbiota-lncRNA/circRNA crosstalk: implications for different diseases

The gut microbiota features an abundance of diverse microorganisms and represents an important component of human physiology and metabolic homeostasis, indicating their roles in a wide array of physiological and pathological processes in the host. Maintaining balance in the gut microbiota is critical for normal functionality as microbial dysbiosis can lead to the occurrence and development of diseases through various mechanisms. Long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) are non-coding RNAs that perform important regulatory functions for many processes. Furthermore, the gut microbiota and lncRNAs/circRNAs are known to interact in a range of both physiological and pathological activities. In this article, we review existing research relevant to the interaction between the gut microbiota and lncRNAs/circRNAs and investigate the role of their crosstalk in the pathogenesis of different diseases. Studies have shown that, the gut microbiota can target lncRNAs ENO1-IT1, BFAL1, and LINC00152 to regulate colorectal cancer development via various signaling pathways. In addition, the gut microbiota can influence mental diseases and lung tumor metastasis by modulating circRNAs such as circNF1-419, circ_0001239, circHIPK2 and mmu_circ_0000730. These findings provide a theoretical basis for disease prevention and treatment and suggest that gut microbiota-lncRNA/circRNA crosstalk has high clinical value.

Biogeography of intestinal mucus-associated microbiome: Depletion of genus Pseudomonas is associated with depressive-like behaviors in female cynomolgus macaques

INTRODUCTION

Depression is a debilitating and poorly understood mental disorder. There is an urgency to explore new potential biological mechanisms of depression and the gut microbiota is a promising research area.

OBJECTIVES

Our study was aim to understand regional heterogeneity and potential molecular mechanisms underlying depression induced by dysbiosis of mucus-associated microbiota.

METHODS

Here, we only selected female macaques because they are more likely to form a natural social hierarchy in a harem-like environment. Because high-ranking macaques rarely displayed depressive-like behaviors, we selected seven monkeys from high-ranking individuals as control group (HC) and the same number of low-ranking ones as depressive-like group (DL), which displayed significant depressive-like behaviors. Then, we collected mucus from the duodenum, jejunum, ileum, cecum and colon of DL and HC monkeys for shotgun metagenomic sequencing, to profile the biogeography of mucus-associated microbiota along duodenum to colon.

RESULTS

Compared with HC, DL macaques displayed noticeable depressive-like behaviors such as longer duration of huddle and sit alone behaviors (negative emotion behaviors), and fewer duration of locomotion, amicable and ingestion activities (positive emotion behaviors). Moreover, the alpha diversity index (Chao) could predict aforementioned depressive-like behaviors along duodenum to colon. Further, we identified that genus Pseudomonas was consistently decreased in DL group throughout the entire intestinal tract except for the jejunum. Specifically, there were 10, 18 and 28 decreased Pseudomonas spp. identified in ileum, cecum and colon, respectively. Moreover, a bacterial module mainly composed of Pseudomonas spp. was positively associated with three positive emotion behaviors. Functionally, Pseudomonaswas mainly involved in microbiota derived lipid metabolisms such as PPAR signaling pathway, cholesterol metabolism, and fat digestion and absorption.

CONCLUSION

Different regions of intestinal mucus-associated microbiota revealed that depletion of genus Pseudomonas is associated with depressive-like behaviors in female macaques, which might induce depressive phenotypes through regulating lipid metabolism.

Gut microbiota-astrocyte axis: new insights into age-related cognitive decline

With the rapidly aging human population, age-related cognitive decline and dementia are becoming increasingly prevalent worldwide. Aging is considered the main risk factor for cognitive decline and acts through alterations in the composition of the gut microbiota, microbial metabolites, and the functions of astrocytes. The microbiota-gut-brain axis has been the focus of multiple studies and is closely associated with cognitive function. This article provides a comprehensive review of the specific changes that occur in the composition of the gut microbiota and microbial metabolites in older individuals and discusses how the aging of astrocytes and reactive astrocytosis are closely related to age-related cognitive decline and neurodegenerative diseases. This article also summarizes the gut microbiota components that affect astrocyte function, mainly through the vagus nerve, immune responses, circadian rhythms, and microbial metabolites. Finally, this article summarizes the mechanism by which the gut microbiota-astrocyte axis plays a role in Alzheimer's and Parkinson's diseases. Our findings have revealed the critical role of the microbiota-astrocyte axis in age-related cognitive decline, aiding in a deeper understanding of potential gut microbiome-based adjuvant therapy strategies for this condition.

The role of microbiome in gut-brain-axis dysbiosis causing depression: From mechanisms to treatment

Gut microbiota not only affects the function of the gastrointestinal tract but also the function of other organs, including the brain. The microbiota-gut-brain axis reflects the constant bidirectional communication between the central nervous system and the gastrointestinal tract. Gut microbiota metabolites can cross brain barriers, the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSF) and influence neuropsychiatric disorders, including depression. In recent years, the communication between the microbiome and brain in depression has been extensively studied in humans and animal models. In this chapter, we summarise the current literature on the role of gut microbiota in depression, focusing in particular on brain barriers and bidirectional gut-brain communication.

Weizmannia coagulans BC99 Improve Cognitive Impairment Induced by Chronic Sleep Deprivation via Inhibiting the Brain and Intestine's NLRP3 Inflammasome

Weizmannia coagulans BC99, a Gram-positive, spore-forming, lactic acid-producing bacterium is renowned for its resilience and health-promoting properties, W. coagulans BC99 survives harsh environments, including high temperatures and gastric acidity, enabling effective delivery to the intestines. The consequences of chronic sleep deprivation (SD) include memory deficits and gastrointestinal dysfunction. In this study, a chronic sleep deprivation cognitive impairment model was established by using a sleep deprivation instrument and W. coagulans BC99 was given by gavage for 4 weeks to explore the mechanism by which BC99 improves cognitive impairment in sleep-deprived mice. BC99 improved cognitive abnormalities in novel object recognition tests induced by chronic sleep deprivation and showed behavior related to spatial memory in the Morris water maze test. W. coagulans BC99 reduced the heart mass index of sleep-deprived mice, increased the sleep-related neurotransmitters 5-HT and DA, decreased corticosterone and norepinephrine, and increased alpha diversity and community similarity. It reduced the abundance of harmful bacteria such as Olsenella, increased the abundance of beneficial bacteria such as Lactobacillus and Bifidobacterium, and promoted the production of short-chain fatty acids (SCFAs). W. coagulans BC99 also inhibits LPS translocation and the elevation of peripheral inflammatory factors by maintaining the integrity of the intestinal barrier and inhibiting the expression of the NLRP3 signaling pathway in the jejunum, thereby inhibiting the NLRP3 inflammasome in the brain of mice and reducing inflammatory factors in the brain, providing a favorable environment for the recovery of cognitive function. The present study confirmed that W. coagulans BC99 ameliorated cognitive impairment in chronic sleep-deprived mice by improving gut microbiota, especially by promoting SCFAs production and inhibiting the NLRP3 signaling pathway in the jejunum and brain. These findings may help guide the treatment of insomnia or other sleep disorders through dietary strategies.

1-Octen-3-ol exacerbates depression-induced neurotoxicity via the TLR4/NF-κB and Nrf2/HO-1 pathways

1-Octen-3-ol is a volatile compound widely found in various fungi and plants, and studies have suggested its potential role in the development of neurodegenerative diseases. However, the mechanism by which 1-octen-3-ol induces neural injury in rats remains unclear. In this study, we used aerosolized 1-octen-3-ol to treat depressive model rats to investigate its effects on neural injury behaviors and neurophysiology in SD rats. The results showed that 1-octen-3-ol significantly increased the lung index to 0.47, reduced the sucrose preference rate to 42.9 %, decreased spontaneous exploration in the open field test, and increased immobility time in the forced swim test. Furthermore, 1-octen-3-ol disrupted blood-brain barrier permeability by reducing the expression of tight junction proteins Occludin and Claudin-1. It also promoted corticosterone secretion, reduced the release of monoamines (serotonin and norepinephrine) and amino acid neurotransmitters (5-hydroxytryptophan), and increased pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β), leading to neuroendocrine damage. Additionally, it reduced the expression of synaptic proteins (PSD-95, Synapsin, and NMDA1) and neurotrophic factors (NT3 and NT4), resulting in impaired neuroplasticity. Simultaneously, 1-octen-3-ol activated the TLR4/NF-κB inflammatory pathway and suppressed the expression of the Nrf2/HO-1 antioxidant pathway, exacerbating neural injury in rats. These findings provide a mechanistic basis for the exacerbation of depression-induced neural injury by 1-octen-3-ol.

Gut Microbiota-Mediated hsa_circ_0126925 Targets BCAA Metabolic Enzyme BCAT2 to Exacerbate Colorectal Cancer Progression

Recent evidence indicates that a high-fat diet can promote tumor development, especially colorectal cancer, by influencing the microbiota. Regulatory circular RNA (circRNA) plays an important role in modulating host-microbe interactions; however, the specific mechanisms by which circRNAs influence cancer progression by regulating these interactions remain unclear. Here, we report that consumption of a high-fat diet modulates the microbiota by specifically upregulating the expression of the noncoding RNA hsa_circ_0126925 (herein, referred to as circ_0126925) in colorectal cancer. Acting as a scaffold, circ_0126925 hinders the recruitment of the E3 ubiquitin ligase tripartite motif-containing protein 21 (TRIM21) to branched-chain amino acid transaminase 2 (BCAT2), leading to reduced degradation of BCAT2. This reduction in targeted degradation of BCAT2 can protect tumors from limited branched-chain amino acid (BCAA) interference by improving the metabolism of BCAAs in colorectal cancer. Taken together, these data demonstrate that circ_0126925 plays a critical role in promoting the progression of colorectal cancer by maintaining BCAA metabolism and provide insight into the functions and crosstalk of circ_0126925 in host-microbe interactions in colorectal cancer. Implications: This study preliminarily confirms that circRNAs do indeed respond to microbiota/microbial metabolites, providing further evidence for the potential development of circRNAs as diagnostic tools and/or therapeutic agents to alleviate microbiome-related pathology in humans.

Embryonic exposure to 6:2 fluorotelomer alcohol mediates autism spectrum disorder-like behavior by dysfunctional microbe-gut-brain axis in mice

6:2 fluorotelomer alcohol (6:2 FTOH) is considered an emerging contaminant as a substitute for perfluoroalkyl and polyfluoroalkyl substances. Autism spectrum disorder (ASD) is a highly heterogeneous childhood neurodevelopmental disorder, the prevalence of which has been significantly increasing globally, possibly due to rising exposure to environmental pollutants. Additionally, the microbe-gut-brain axis plays a crucial role in the development of ASD. The purpose of study was to investigate the impact of embryonic 6:2 FTOH exposure on neurological development in mice and explore the potential involvement of the microbe-gut-brain. Pregnant mice were orally administered 6:2 FTOH from gestation day 8.5 until delivery, and follow-up testing was performed on day 22 post-delivery. The findings revealed that embryonic exposure to 6:2 FTOH led to ASD-like symptoms, cortical neuron apoptosis, glial cell activation, and abnormal synapse formation in mice. Furthermore, impairment of colonic barrier function, inflammatory response, and dysbiosis in gut microbiota were observed. Interestingly, supplementation with Lactobacillus rhamnosus GG during embryonic development mitigated these adverse outcomes. This study enhances our understanding of how environmental pollutants can impact neurological development in children and provides valuable insights for clinical prevention, diagnosis, and treatment strategies for non-genetic ASD.

Mannuronate Oligosaccharides Ameliorate Experimental Colitis and Secondary Neurological Dysfunction by Manipulating the Gut-Brain Axis

Microbiota dysfunction induces intestinal disorders and neurological diseases. Mannuronate oligosaccharides (MAOS), a kind of alginate oligosaccharide (AOS), specifically exert efficacy in shaping gut microbiota and relieving cognitive impairment. However, the key regulatory factors involved, such as the specific strains and metabolites as well as their regulatory mechanisms, remain unclear at present. This research investigates how MAOS specifically impact the gut-brain axis in vivo and in vitro. The results showed that pretreatment with MAOS significantly ameliorated dextran sodium sulfate (DSS)-induced colitis and secondary nerve injury. This preventive mechanism operates through the regulation of serum DOPC abundance and the gut-brain axis, achieved by inhibiting the TLR4/MyD88/NF-κB pathway. These findings underscore the crucial role of dietary MAOS in the prevention of colitis and neurological disorders, providing a rationale for the application of MAOS in disease prevention and functional food ingredients.

Circular RNAs in cancer

Circular RNA (circRNA), a subtype of noncoding RNA, has emerged as a significant focus in RNA research due to its distinctive covalently closed loop structure. CircRNAs play pivotal roles in diverse physiological and pathological processes, functioning through mechanisms such as miRNAs or proteins sponging, regulation of splicing and gene expression, and serving as translation templates, particularly in the context of various cancers. The hallmarks of cancer comprise functional capabilities acquired during carcinogenesis and tumor progression, providing a conceptual framework that elucidates the nature of the malignant transformation. Although numerous studies have elucidated the role of circRNAs in the hallmarks of cancers, their functions in the development of chemoradiotherapy resistance remain unexplored and the clinical applications of circRNA-based translational therapeutics are still in their infancy. This review provides a comprehensive overview of circRNAs, covering their biogenesis, unique characteristics, functions, and turnover mechanisms. We also summarize the involvement of circRNAs in cancer hallmarks and their clinical relevance as biomarkers and therapeutic targets, especially in thyroid cancer (TC). Considering the potential of circRNAs as biomarkers and the fascination of circRNA-based therapeutics, the "Ying-Yang" dynamic regulations of circRNAs in TC warrant vastly dedicated investigations.

CircKat6b Mediates the Antidepressant Effect of Esketamine by Regulating Astrocyte Function

The abundant expression of circular RNAs (circRNAs) in the central nervous system and their contribution to the pathogenesis of depression suggest that circRNAs are promising therapeutic targets for depression. This study explored the role and mechanism of circKat6b in esketamine's antidepressant effect. We found that intravenous administration of esketamine (5 mg/kg) treatment decreased the circKat6b expression in the astrocytes of hippocampus induced by a chronic unpredictable mild stress (CUMS) mouse model, while the overexpression of circKat6b in the hippocampus significantly attenuated the antidepressant effects of esketamine in depressed mice. RNA-sequencing, RT-PCR, and western blot experiments showed that the stat1 and p-stat1 expression were significantly upregulated in mouse astrocytes overexpressing circKat6b. In the CUMS mouse model, overexpression of circKat6b in the hippocampus significantly reversed the downregulation of p-stat1 protein expression caused by esketamine. Our findings demonstrated that a novel mechanism of the antidepressant like effect of esketamine may be achieved by reducing the expression of circKat6b in the astrocyte of the hippocampus of depressed mice.

The Role and the Regulation of NLRP3 Inflammasome in Irritable Bowel Syndrome: A Narrative Review

Irritable bowel syndrome (IBS) is a chronic disorder of the gastrointestinal tract. Its pathogenesis involves multiple factors, including visceral hypersensitivity and immune activation. NLRP3 inflammasome is part of the nucleotide-binding oligomerization domain-like receptor (NLR) family, a crucial component of the innate immune system. Preclinical studies have demonstrated that inhibiting NLRP3 reduces visceral sensitivity and IBS symptoms, like abdominal pain, and diarrhea, suggesting that targeting the NLRP3 might represent a novel therapeutic approach for IBS. This review aims to assess the NLRP3 inhibitors (tranilast, β-hydroxybutyrate, Chang-Kang-fang, paeoniflorin, coptisine, BAY 11-7082, and Bifidobacterium longum), highlighting the signaling pathways, and their potential role in IBS symptoms management was assessed. Although premature, knowledge of the action of synthetic small molecules, phytochemicals, organic compounds, and probiotics might make NLRP3 a new therapeutic target in the quiver of physicians' therapeutic choices for IBS symptoms management.

MicroRNA-specific targets for neuronal plasticity, neurotransmitters, neurotrophic factors, and gut microbes in the pathogenesis and therapeutics of depression

Depression is of great concern because of the huge burden, and it is impacted by various epigenetic modifications, e.g., histone modification, covalent modifications in DNA, and silencing mechanisms of non-coding protein genes, e.g., microRNAs (miRNAs). MiRNAs are a class of endogenous non-coding RNAs. Alternations in specific miRNAs have been observed both in depressive patients and experimental animals. Also, miRNAs are highly expressed in the central nervous system and can be delivered to different tissues via tissue-specific exosomes. However, the mechanism of miRNAs' involvement in the pathological process of depression is not well understood. Therefore, we summarized and discussed the role of miRNAs in depression. Conclusively, miRNAs are involved in the pathology of depression by causing structural and functional changes in synapses, mediating neuronal regeneration, differentiation, and apoptosis, regulating the gut microbes and the expression of various neurotransmitters and BDNF, and mediating inflammatory and immune responses. Moreover, miRNAs can predict the efficacy of antidepressant medications and explain the mechanism of action of antidepressant drugs and aerobic exercise to prevent and assist in treating depression.

Evidence for the contribution of vasopressin V1B receptors in the pathophysiology of depression

Depression is a chronic and recurrent psychiatric condition characterised by depressed mood, loss of interest or pleasure, poor sleep, low appetite, and poor concentration. Research has shown that both heritable and environmental risk factors are involved in the pathogenesis of depression. In addition, several studies have indicated that dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis is implicated in the development of depression in adulthood. However, the mechanism underlying the activation of HPA axis-induced depression remains unclear. Arginine vasopressin (AVP), also known as vasopressin (VP), is a hormone synthesised in the hypothalamus that plays important roles in numerous biological functions in mammals, including the regulation of stress and anxiety, and has been implicated in the pathogenesis of many disorders. VP regulates pituitary corticotroph function by binding to the plasma membrane G-protein receptors of the V1B receptor (V1BR), which are coupled to calcium-phospholipid signalling. V1BR, a receptor subtype of VP, plays a pivotal role in HPA axis abnormalities observed in depression. In animals, V1BR antagonists reduce plasma stress hormone levels and have been shown to have antidepressant activity. However, the precise mechanism of V1BR in modulating HPA axis activity remains unclear. We therefore reviewed and integrated the clinical and preclinical literature pertinent to the role of V1BR in depression, while emphasising the effect of V1BR antagonists on attenuating the hyperactivity of the HPA axis. In addition, therapy for depression through the regulation of the HPA axis is briefly discussed. Although effective antidepressants are available, a large proportion of patients do not respond to initial treatment. Therefore, this review describes the exact mechanisms of V1BR in depression and contributes to the development of new therapeutic strategies for this disease.

Is anxiety and depression transmissible? Depressed mother rats transmit anxiety- and depression-like phenotypes to cohabited rat pups through gut microbiota assimilation

OBJECTIVE

This study is to investigate the role of gut microbiota transmission in the development of anxiety/depression in offspring exposed to maternal depression.

METHOD

Offspring rats were cohabitated with their depressed mother or father rats (which exposed to chronic unpredictable mild stress (CUMS)) for 2, 4, and 6 months, the anxiety- and depression-like behaviors, and interaction/caring activities between mother/father and their pups were detected. The gut microbiota composition and its relationship with behaviors were analyzed. Fecal microbiota transplantation (FMT) was performed to establish the gut microbiota of depressed/normal mother rats in the offspring rats to further confirm the role of "depressive gut microbiota" transmission in mediating the anxiety/depression in the pups.

RESULTS

Anxiety and depression phenotypes can be transmitted from depressed mother rats to their cohabited offspring. Frequent interactions and gut microbiota assimilation were observed between rat mothers and their pups. Remodeling of the gut microbiota in pups by FMT could induce or attenuate anxiety- and depression-like phenotypes depending on the origin of the fecal microbiota. By comparison, the pups cohabiting with depressed father rats exhibited milder anxiety and depression.

CONCLUSIONS

These data together support that depressed mothers can transmit anxiety/depression to their pups through gut microbiota assimilation, which is related to frequent interactions. Our study reinforces the significance of mental health of mothers in preventing the occurrence of childhood anxiety and depression, and pointing out the possibility of remodeling intestinal microbiota as an effective therapeutic approach for treating anxiety/depression in children.

Ginsenoside Rg1: A Neuroprotective Natural Dammarane-Type Triterpenoid Saponin With Anti-Depressive Properties

BACKGROUND

Depression, a widespread mental disorder, presents significant risks to both physical and mental health due to its high rates of recurrence and suicide. Currently, single-target antidepressants typically alleviate depressive symptoms or delay the progression of depression rather than cure it. Ginsenoside Rg1 is one of the main ginsenosides found in Panax ginseng roots. It improves depressive symptoms through various mechanisms, suggesting its potential as a treatment for depression.

MATERIALS AND METHODS

We evaluated preclinical studies to comprehensively discuss the antidepressant mechanism of ginsenoside Rg1 and review its toxicity and medicinal value. Additionally, pharmacological network and molecular docking analyses were performed to further validate the antidepressant effects of ginsenoside Rg1.

RESULTS

The antidepressant mechanism of ginsenoside Rg1 may involve various pharmacological mechanisms and pathways, such as inhibiting neuroinflammation and over-activation of microglia, preserving nerve synapse structure, promoting neurogenesis, regulating monoamine neurotransmitter levels, inhibiting hyperfunction of the hypothalamic-pituitary-adrenal axis, and combatting antioxidative stress. Moreover, ginsenoside Rg1 preserves astrocyte gap junction function by regulating connexin43 protein biosynthesis and degradation, contributing to its antidepressant effect. Pharmacological network and molecular docking studies identified five targets (AKT1, STAT3, EGFR, PPARG, and HSP90AA1) as potential molecular regulatory sites of ginsenoside Rg1.

CONCLUSIONS

Ginsenoside Rg1 may exert its antidepressant effects via various pharmacological mechanisms. In addition, multicenter clinical case-control and molecular targeted studies are required to confirm both the clinical efficacy of ginsenoside Rg1 and its potential direct targets.

Mechanism of Resveratrol on LPS/ATP-induced pyroptosis and inflammatory response in HT29 cells

Pyroptosis plays an important role in maintenance of intestinal homeostasis, the abnormal activation of NOD-like receptor thermal protein domain-associated protein 3 (NLRP3) inflammasome can promote the event and development of ulcerative colitis (UC). Its protective effects such as inhibiting pyroptosis in various inflammation-related diseases have been demonstrated, but whether resveratrol (RES) can also alleviate the progression of the disease by inhibiting pyroptosis in UC and the mechanism have rarely been studied. In this study, lipopolysaccharide (LPS) combined with adenosine triphosphate (ATP) was used to induce HT29 human colon cancer cells to construct an intestinal epithelial cell pyroptosis and inflammation model in vitro to investigate the anti-inflammatory effect of RES, reveal the regulatory mechanism of RES on pyroptosis, and provide a new theoretical basis for the treatment of UC. In vitro experiences, HT29 cells were dividing into control group, LPS/ATP group, RES low-dose group, RES high-dose group, NF-κB inhibitor pyrrolidine dithiocarbamate group (PDTC group), and LPS/ATP+PDTC group. The mRNA expressions of pyroptosis-related indicators such as NLRP3, apoptosis-associated speck-like protein containing CARD (ASC), Caspase-1(CASP1), IL-18, IL-1β, and inflammatory factors such as TNF-α and IL-6 were detected by qRT-PCR. The protein expressions of pyroptosis-related indicators NLRP3, ASC, CASP1, IL-18, IL-1β, NF-κB-p65 in the nucleus, and IκBα and p-IκBα in the cytoplasm were detected by Western blot. Immunofluorescence saw the distribution and expression of NLRP3, ASC and NF-κB-p65 protein in each group. The morphology and degree of pyroptosis in each group were observed by transmission electron microscope. The results showed that compared with the control group, the pyroptosis-related proteins including NLRP3, ASC, CASP1, IL-18, IL-1β, and inflammatory factors including TNF-α and IL-6 in the LPS/ATP group were increased, and LPS/ATP activated the activity of NF-κB signaling pathway. Compared with the LPS/ATP group, RES downregulated the expression of pyroptosis-related proteins and inflammatory factors in HT29 cells, and inhibited the activation of the NF-κB signaling pathway in HT29 cells pyroptosis. RES down-regulates the pyroptosis of HT29 cells induced by LPS/ATP and the expression of pyroptosis-related indicators NLRP3, ASC, CASP1, IL-18, IL-1β and inflammatory factors TNF-α and IL-6 in the inflammatory response and inhibits the occurrence of pyroptosis. The mechanism is related to the inhibition of NF-κB pathway activity.

Hypoxanthine Produces Rapid Antidepressant Effects by Suppressing Inflammation in Serum and Hippocampus

The occurrence and development of depression are closely related to disorders of the brain and peripheral substances. Abnormal metabolites in the blood affect the signal regulation function of the nerve center, which is one of the key factors for depression episodes. This study was focused on metabolites in serum and the mechanism of its antidepressant in the hippocampus. In the present study, serum metabolites in patients with depression were screened by metabolomic techniques. Various depressive mouse models and behavioral tests were used to assess its antidepressant effects. The expressions of inflammatory signaling were detected by using Western blot, ELISA, and immunofluorescence. We found that the metabolite hypoxanthine in the serum of patients with depression was significantly reduced, and the same result was also found in two mouse models of depression such as chronic unpredictable mild stress (CUMS) and social defeat stress (SD). By administering different doses of hypoxanthine (5, 10, 15 mg/kg), we found that only 15 mg/kg was able to significantly reduce the latency and increase food consumption in the novelty suppressed-feeding test (NSF), which was also able to reverse the depressive phenotypes of mice in the CUMS model after a single administration at 2 h later. Hypoxanthine obviously reduced the expressions of inflammation in serum and downregulated the expressions of MAPK and NLRP3-related pathways in the hippocampus in CUMS mice. Moreover, hypoxanthine also suppressed the activations of glial cells including GFAP and IBA-1 in hippocampal CA1, CA3, and dentate gyrus (DG). To sum up, hypoxanthine exerted antidepressant effect relying on the inhibition of peripheral and hippocampal inflammations by regulating MAPK, NLRP3-related pathways, and glial cells. This was the first time that we have found a disordered metabolite in patients with depression and further systematically demonstrated its efficacy and potential mechanism of antidepressants, providing new ideas for antidepressant drug development.

Aberrant Enhanced NLRP3 Inflammasomes and Cell Pyroptosis in the Brains of Prion-Infected Rodent Models Are Largely Associated with the Proliferative Astrocytes

Neuroinflammation is a common pathological feature in a number of neurodegenerative diseases, which is mediated primarily by the activated glial cells. Nucleotide-binding oligomerization domain-like receptor pyrin domain-containing-3 (NLRP3) inflammasome-associated neuroinflammatory response is mostly considered. To investigate the situation of the NLRP3-related inflammation in prion disease, we assessed the levels of the main components of NLRP3 inflammasome and its downstream biomarkers in the scrapie-infected rodent brain tissues. The results showed that the transcriptional and expressional levels of NLRP3, caspase-1, and apoptosis-associated speck-like protein (ASC) in the brains of scrapie-infected rodents were significantly increased at terminal stage. The increased NLPR3 overlapped morphologically well with the proliferated GFAP-positive astrocytes, but little with microglia and neurons. Using the brain samples collected at the different time-points after infection, we found the NLRP3 signals increased in a time-dependent manner, which were coincidental with the increase of GFAP. Two main downstream cytokines, IL-1β and IL-18, were also upregulated in the brains of prion-infected mice. Moreover, the gasdermin D (GSDMD) levels, particularly the levels of GSDMD-NT, in the prion-infected brain tissues were remarkably increased, indicating activation of cell pyroptosis. The GSDMD not only co-localized well with the astrocytes but also with neurons at terminal stage, also showing a time-dependent increase after infection. Those data indicate that NLRP3 inflammasomes were remarkably activated in the infected brains, which is largely mediated by the proliferated astrocytes. Both astrocytes and neurons probably undergo a pyroptosis process, which may help the astrocytes to release inflammatory factors and contribute to neuron death during prion infection.

EphA2 blockage ALW-II-41-27 alleviates atherosclerosis by remodeling gut microbiota to regulate bile acid metabolism

Coronary artery disease (CAD), a critical condition resulting from systemic inflammation, metabolic dysfunction, and gut microbiota dysbiosis, poses a global public health challenge. ALW-II-41-27, a specific inhibitor of the EphA2 receptor, has shown anti-inflammatory prosperities. However, the impact of ALW-II-41-27 on atherosclerosis has not been elucidated. This study aimed to examine the roles of pharmacologically inhibiting EphA2 and the underlying mechanism in ameliorating atherosclerosis. ALW-II-41-27 was administered to apoE-/- mice fed a high-fat diet via intraperitoneal injection. We first discovered that ALW-II-41-27 led to a significant reduction in atherosclerotic plaques, evidenced by reduced lipid and macrophage accumulation, alongside an increase in collagen and smooth muscle cell content. ALW-II-41-27 also significantly lowered plasma and hepatic cholesterol levels, as well as the colonic inflammation. Furthermore, gut microbiota was analyzed by metagenomics and plasma metabolites by untargeted metabolomics. ALW-II-41-27-treated mice enriched Enterococcus, Akkermansia, Eggerthella and Lactobaccilus, accompanied by enhanced secondary bile acids production. To explore the causal link between ALW-II-41-27-associated gut microbiota and atherosclerosis, fecal microbiota transplantation was employed. Mice that received ALW-II-41-27-treated mouse feces exhibited the attenuated atherosclerotic plaque. In clinical, lower plasma DCA and HDCA levels were determined in CAD patients using quantitative metabolomics and exhibited a negative correlation with higher monocytes EphA2 expression. Our findings underscore the potential of ALW-II-41-27 as a novel therapeutic agent for atherosclerosis, highlighting its capacity to modulate gut microbiota composition and bile acid metabolism, thereby offering a promising avenue for CAD.

Alterations in microbiota-metabolism-circRNA crosstalk in autism spectrum disorder-like behaviours caused by maternal exposure to glyphosate-based herbicides in mice

Epidemiological evidence indicates exposure to glyphosate-based herbicides (GBHs) increases the risk for autism spectrum disorder (ASD). The gut microbiota has been found to influence ASD behaviours through the microbiota-gut-brain axis. However, the underlying links between early life GBH exposure and ASD-like phenotypes through the microbiota-gut-brain axis remain unclear. Therefore, we exposed mice to low-dose GBH (0.10, 0.25, 0.50, and 1.00 %) and determined the effects on ASD-like behaviours. Furthermore, three kinds of omics (gut microbiomics, metabolomics, and transcriptomics) were conducted to investigate the effects of GBH exposure on gut microbiota, gut metabolites, and circular RNAs (circRNAs) in the prefrontal cortex (PFC) using a cross-generational mouse model. Behavioural analyses suggested social impairment and repetitive/stereotypic behaviours in the GBH-exposed offspring. Furthermore, maternal exposure to glyphosate significantly altered the ASD-associated gut microbiota of offspring, and ASD-associated gut metabolites were identified. Specifically, we found that alterations in the gut microenvironment may contribute to changes in gut permeability and the blood-brain barrier, which are related to changes in the levels of circRNAs in the PFC. Our results suggest a potential effect of circRNAs through the disruption of the gut-brain interaction, which is an important factor in the pathogenesis of ASD in offspring induced by maternal exposure to GBH.

Acupuncture ameliorates depression-like behavior of poststroke depression model rats through the regulation of gut microbiota and NLRP3 inflammasome in the colon

This study was conducted to examine the effects of acupuncture on gut microbiota and expression of NLRP3 inflammasome in the colon in poststroke depression (PSD) model rats. Sprague-Dawley male rats were randomized into four groups: sham surgery group, poststroke depression group, acupuncture group, and probiotics group. Acupuncture therapy at Baihui (GV20), Shenting (GV24), bilateral Zusanli (ST36) acupoints in the acupuncture group and probiotic gavage therapy in the probiotics group were performed once per day for 2 weeks. Behaviors of depression were assessed by using weight measurements, sucrose preference test, open field test, and forced swimming test. Histopathological alterations in the colon were determined by hematoxylin-eosin staining, the expression of NLRP3/ASC/caspase-1 pathway-related proteins was analyzed by western blotting. Serum levels of IL-1β and IL-18 were derived from ELISA. The 16S rRNA gene sequencing was performed to examine and analyze the differences of gut microbiota of rats among all groups. Acupuncture was effective to increase weight and ameliorate depressive-like behaviors in PSD rats. Acupuncture increased the diversity of gut microbiota, upregulated the abundance of Bifidobacteriaceae and Lactobacillaceae, and decreased the relative abundance of Peptostreptococcaceae, Rikenellaceae, Eggerthellaceae, and Streptococcaceae at family level. Acupuncture effectively improved the pathological changes in the colon. Meanwhile, acupuncture reduced NLRP3, ASC, caspase-1 protein expressions in the colon, and serum levels of IL-18 and IL-1β. Acupuncture may reduce depressive-like behaviors of PSD by regulating the gut microbiota and suppressing hyperactivation of NLRP3 inflammasome in the colon. Microbiota-gut-brain axis may be an effective target pathway for acupuncture treatment of PSD.

Gut microbiota-NLRP3 inflammasome crosstalk in metabolic dysfunction-associated steatotic liver disease

Nonalcoholic fatty liver disease (NAFLD) is a chronic liver disease associated with metabolic dysfunction, ranging from hepatic steatosis with or without mild inflammation to nonalcoholic steatohepatitis, which can rapidly progress to liver fibrosis and even liver cancer. In 2023, after several rounds of Delphi surveys, a new consensus recommended renaming NAFLD as metabolic dysfunction-associated steatotic liver disease (MASLD). Ninety-nine percent of NAFLD patients meet the new MASLD criteria related to metabolic cardiovascular risk factors under the "multiple parallel hits" of lipotoxicity, insulin resistance (IR), a proinflammatory diet, and an intestinal microbiota disorder, and previous research on NAFLD remains valid. The NLRP3 inflammasome, a well-known member of the pattern recognition receptor (PRR) family, can be activated by danger signals transmitted by pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs), as well as cytokines involved in immune and inflammatory responses. The activation of the NLRP3 inflammasome pathway by MASLD triggers the production of the inflammatory cytokines IL-1β and IL-18. In MASLD, while changes in the composition and metabolites of the intestinal microbiota occur, the disrupted intestinal microbiota can also generate the inflammatory cytokines IL-1β and IL-18 by damaging the intestinal barrier, negatively regulating the liver on the gut-liver axis, and further aggravating MASLD. Therefore, modulating the gut-microbiota-liver axis through the NLRP3 inflammasome may emerge as a novel therapeutic approach for MASLD patients. In this article, we review the evidence regarding the functions of the NLRP3 inflammasome and the intestinal microbiota in MASLD, as well as their interactions in this disease.

Salidroside exerts antidepressant-like action by promoting adult hippocampal neurogenesis through SIRT1/PGC-1α signalling

Depression is one of the major mental disorders, which seriously endangers human health, brings a serious burden to patients’ families. In this study, we intended to further explore the antidepressant-like effect and possible molecular mechanisms of Salidroside (SAL). We built corticosterone (CORT)-induced depressive mice model and used behavioural tests to evaluate depression behaviour. To explore the molecular mechanisms of SAL, we employed a variety of methods such as immunofluorescence, western blot, pharmacological interference, etc. The results demonstrated that SAL both at 25 mg/kg and 50 mg/kg can reduce immobility time in the tail suspension test (TST). At the same time, SAL treatment could restore the reduced sugar water intake preference in the sucrose preference test (SPT) in CORT-induced depressive mice and reduce the immobility time in TST and forced swimming experiments (FST). In addition, SAL treatment reversed the reduction in the number of Ki-67, BrdU, and NeuN in the hippocampus due to CORT treatment. SAL treatment also restored the expression of SIRT1, PGC-1α, brain-derived neurotrophic factor (BDNF) and other proteins in the hippocampus. In addition, after blocking SIRT1 signalling with EX527, we found that the treatment with SAL failed to reduce the immobility time in TST and FST, the level of SIRT1 and PGC-1α activity were correspondingly downregulated, and the expression of DCX and Ki-67 in the hippocampus failed to be activated. These findings suggested that SAL exerts antidepressant-like effects by promoting hippocampal neurogenesis through the SIRT1/PGC-1α signalling pathway.

The communication mechanism of the gut-brain axis and its effect on central nervous system diseases: A systematic review

Gut microbiota is involved in intricate and active metabolic processes the host's brain function, especially its role in immune responses, secondary metabolism, and symbiotic connections with the host. Gut microbiota can promote the production of essential metabolites, neurotransmitters, and other neuroactive chemicals that affect the development and treatment of central nervous system diseases. This article introduces the relevant pathways and manners of the communication between the brain and gut, summarizes a comprehensive overview of the current research status of key gut microbiota metabolites that affect the functions of the nervous system, revealing those adverse factors that affect typical communication between the brain-gut axis, and outlining the efforts made by researchers to alleviate these neurological diseases through targeted microbial interventions. The relevant pathways and manners of communication between the brain and gut contribute to the experimental design of new treatment plans and drug development. The factors that may cause changes in gut microbiota and affect metabolites, as well as current intervention methods are summarized, which helps improve gut microbiota brain dialogue, prevent adverse triggering factors from interfering with the gut microbiota system, and minimize neuropathological changes.

Distinguishing bipolar depression, bipolar mania, and major depressive disorder by gut microbial characteristics

BACKGROUND

Gut microbial disturbance has been widely confirmed in mood disorders. However, little is known about whether gut microbial characteristics can distinguish major depressive disorder (MDD), bipolar depression (BP-D), and bipolar mania (BP-M).

METHODS

This was a prospective case-control study. The composition of gut microbiota was profiled using 16S ribosomal RNA (rRNA) gene sequencing of fecal samples and compared between healthy controls (HC; n = 46), MDD (n = 51), BP-D (n = 44), and patients with BP-M (n = 45).

RESULTS

Gut microbial compositions were remarkably changed in the patients with MDD, BP-D, and BP-M. Compared to HC, distinct gut microbiome signatures were found in MDD, BP-D, and BP-M, and some gut microbial changes were overlapping between the three mood disorders. Furthermore, we identified a signature of 7 operational taxonomic units (OUT; Prevotellaceae-related OUT22, Prevotellaceae-related OUT31, Prevotellaceae-related OTU770, Ruminococcaceae-related OUT70, Bacteroidaceae-related OTU1536, Propionibacteriaceae-related OTU97, Acidaminococcaceae-related OTU34) that can distinguish patients with MDD from those with BP-D, BP-M, or HC, with area under the curve (AUC) values ranging from 0.910 to 0.996.

CONCLUSION

Our results provide the clinical rationale for the discriminative diagnosis of MDD, BP-D, and BP-M by characteristic gut microbial features.

Advances in biosensors for major depressive disorder diagnostic biomarkers

Depression is one of the most common mental disorders and is mainly characterized by low mood or lack of interest and pleasure. It can be accompanied by varying degrees of cognitive and behavioral changes and may lead to suicide risk in severe cases. Due to the subjectivity of diagnostic methods and the complexity of patients' conditions, the diagnosis of major depressive disorder (MDD) has always been a difficult problem in psychiatry. With the discovery of more diagnostic biomarkers associated with MDD in recent years, especially emerging non-coding RNAs (ncRNAs), it is possible to quantify the condition of patients with mental illness based on biomarker levels. Point-of-care biosensors have emerged due to their advantages of convenient sampling, rapid detection, miniaturization, and portability. After summarizing the pathogenesis of MDD, representative biomarkers, including proteins, hormones, and RNAs, are discussed. Furthermore, we analyzed recent advances in biosensors for detecting various types of biomarkers of MDD, highlighting representative electrochemical sensors. Future trends in terms of new biomarkers, new sample processing methods, and new detection modalities are expected to provide a complete reference for psychiatrists and biomedical engineers.

Reduction in Renal Interstitial Fibrosis in Aged Male Mice by Intestinal Microbiota Rejuvenation

INTRODUCTION

Renal interstitial fibrosis is an important pathological basis for kidney ageing and the progression of ageing nephropathy. In the present research, we established an aged mouse model of faecal microbiota transplantation (FMT), identified the rejuvenation features of the kidney in aged male mice, and preliminarily analysed the possible mechanism by which the rejuvenation of the intestinal microbiota reduces renal interstitial fibrosis and delays senescence in aged male mice.

METHODS

We established an aged male mice model that was treated with FMT (FMT-Old) and a normal aged male mice control group (Old). Differentially expressed cytokines were identified using a cytokine array, and changes in protein expression related to signal transduction pathways in renal tissues were detected using a signalling pathway array. Senescence-associated β-galactosidase and Masson staining were performed to observe the degrees of renal senescence and tubule interstitial fibrosis. Immunohistochemistry was utilized to detect changes in the expression of the ageing markers p53 and p21 and the inflammation-related protein nuclear factor (NF-κB) subunit (RelA/p65).

RESULTS

The pathological features of renal senescence in the FMT-Old group were significantly alleviated, and the levels of the ageing indicators p53 and p21 were decreased (p < 0.05). Ingenuity Pathway Analysis revealed that six differentially expressed cytokines, MIP-3β (CCL-19), E-selectin (SELE), Fas ligand (Fas L/FASLG), CXCL-11 (I-TAC), CXCL-1 and CCL-3 (MIP-1α) were related to a common upstream regulatory protein, RelA/p65, and the expression of this protein was significantly different between groups according to the signalling pathway array.

CONCLUSION

Our findings suggest that the intestinal microbiota regulates the renal microenvironment by reducing immune inflammatory responses through the inhibition of the NF-κB signalling pathway, thereby delaying renal senescence in aged male mice.

The gut microbiota-brain axis in neurological disorders

Previous studies have shown a bidirectional communication between human gut microbiota and the brain, known as the microbiota-gut-brain axis (MGBA). The MGBA influences the host's nervous system development, emotional regulation, and cognitive function through neurotransmitters, immune modulation, and metabolic pathways. Factors like diet, lifestyle, genetics, and environment shape the gut microbiota composition together. Most research have explored how gut microbiota regulates host physiology and its potential in preventing and treating neurological disorders. However, the individual heterogeneity of gut microbiota, strains playing a dominant role in neurological diseases, and the interactions of these microbial metabolites with the central/peripheral nervous systems still need exploration. This review summarizes the potential role of gut microbiota in driving neurodevelopmental disorders (autism spectrum disorder and attention deficit/hyperactivity disorder), neurodegenerative diseases (Alzheimer's and Parkinson's disease), and mood disorders (anxiety and depression) in recent years and discusses the current clinical and preclinical gut microbe-based interventions, including dietary intervention, probiotics, prebiotics, and fecal microbiota transplantation. It also puts forward the current insufficient research on gut microbiota in neurological disorders and provides a framework for further research on neurological disorders.

Exploring the relationship between gut microbial ecology and inflammatory disease: An insight into health and immune function

The immune system, host brain development, and general metabolism are all influenced by the gut bacteria. Bacteria make up the majority of the gut microbiota in mammals. The mouse has been the most often used animal model in preclinical biological research. In mice, Firmicutes and Clostridiales are prominent. On the other hand, Bacteroidaceae, Prevotellaceae, and Firmicutes are commonly found in humans. In this review, we performed a detailed study by focusing on a comparison between human and murine gut microbiomes, role of the microbiome and their secreted metabolites in regulating gut immunity to maintain homeostasis, and changes in the microbial composition in the dysbiotic state.

NLRP3-mediated autophagy dysfunction links gut microbiota dysbiosis to tau pathology in chronic sleep deprivation

Emerging evidence indicates that sleep deprivation (SD) can lead to Alzheimer's disease (AD)-related pathological changes and cognitive decline. However, the underlying mechanisms remain obscure. In the present study, we identified the existence of a microbiota-gut-brain axis in cognitive deficits resulting from chronic SD and revealed a potential pathway by which gut microbiota affects cognitive functioning in chronic SD. Our findings demonstrated that chronic SD in mice not only led to cognitive decline but also induced gut microbiota dysbiosis, elevated NLRP3 inflammasome expression, GSK-3β activation, autophagy dysfunction, and tau hyperphosphorylation in the hippocampus. Colonization with the "SD microbiota" replicated the pathological and behavioral abnormalities observed in chronic sleep-deprived mice. Remarkably, both the deletion of NLRP3 in NLRP3 -/- mice and specific knockdown of NLRP3 in the hippocampus restored autophagic flux, suppressed tau hyperphosphorylation, and ameliorated cognitive deficits induced by chronic SD, while GSK-3β activity was not regulated by the NLRP3 inflammasome in chronic SD. Notably, deletion of NLRP3 reversed NLRP3 inflammasome activation, autophagy deficits, and tau hyperphosphorylation induced by GSK-3β activation in primary hippocampal neurons, suggesting that GSK-3β, as a regulator of NLRP3-mediated autophagy dysfunction, plays a significant role in promoting tau hyperphosphorylation. Thus, gut microbiota dysbiosis was identified as a contributor to chronic SD-induced tau pathology via NLRP3-mediated autophagy dysfunction, ultimately leading to cognitive deficits. Overall, these findings highlight GSK-3β as a regulator of NLRP3-mediated autophagy dysfunction, playing a critical role in promoting tau hyperphosphorylation.

Short-chain fatty acids suppresses astrocyte activation by amplifying Trp-AhR-AQP4 signaling in experimental autoimmune encephalomyelitis mice

The function of astrocytes in response to gut microbiota-derived signals has an important role in the pathophysiological processes of central nervous system (CNS) diseases. However, the specific effects of microbiota-derived metabolites on astrocyte activation have not been elucidated yet. Experimental autoimmune encephalomyelitis (EAE) was induced in female C57BL/6 mice as a classical MS model. The alterations of gut microbiota and the levels of short-chain fatty acids (SCFAs) were assessed after EAE induction. We observed that EAE mice exhibit low levels of Allobaculum, Clostridium_IV, Clostridium_XlVb, Lactobacillus genera, and microbial-derived SCFAs metabolites. SCFAs supplementation suppressed astrocyte activation by increasing the level of tryptophan (Trp)-derived AhR ligands that activating the AhR. The beneficial effects of SCFAs supplementation on the clinical scores, histopathological alterations, and the blood brain barrier (BBB)-glymphatic function were abolished by intracisterna magna injection of AAV-GFAP-shAhR. Moreover, SCFAs supplementation suppressed the loss of AQP4 polarity within astrocytes in an AhR-dependent manner. Together, SCFAs potentially suppresses astrocyte activation by amplifying Trp-AhR-AQP4 signaling in EAE mice. Our study demonstrates that SCFAs supplementation may serve as a viable therapy for inflammatory disorders of the CNS.

Microglial circ-UBE2K exacerbates depression by regulating parental gene UBE2K via targeting HNRNPU

Background: Knowledge about the pathogenesis of depression and treatments for this disease are lacking. Epigenetics-related circRNAs are likely involved in the mechanism of depression and have great potential as treatment targets, but their mechanism of action is still unclear. Methods: Circular RNA UBE2K (circ-UBE2K) was screened from peripheral blood of patients with major depressive disorder (MDD) and brain of depression model mice through high-throughput sequencing. Microinjection of circ-UBE2K overexpression lentivirus and adeno-associated virus for interfering with microglial circ-UBE2K into the mouse hippocampus was used to observe the role of circ-UBE2K in MDD. Sucrose preference, forced swim, tail suspension and open filed tests were performed to evaluate the depressive-like behaviors of mice. Immunofluorescence and Western blotting analysis of the effects of circ-UBE2K on microglial activation and immune inflammation. Pull-down-mass spectrometry assay, RNA immunoprecipitation (RIP) test and fluorescence in situ hybridization (FISH) were used to identify downstream targets of circ-UBE2K/ HNRNPU (heterogeneous nuclear ribonucleoprotein U) axis. Results: In this study, through high-throughput sequencing and large-scale screening, we found that circ-UBE2K levels were significantly elevated both in the peripheral blood of patients with MDD and in the brains of depression model mice. Functionally, circ-UBE2K-overexpressing mice exhibited worsened depression-like symptoms, elevated brain inflammatory factor levels, and abnormal microglial activation. Knocking down circ-UBE2K mitigated these changes. Mechanistically, we found that circ-UBE2K binds to heterogeneous nuclear ribonucleoprotein U (HNRNPU) to form a complex that upregulates the expression of the parental gene ubiquitin conjugating enzyme E2 K (UBE2K), leading to abnormal microglial activation and neuroinflammation and promoting the occurrence and development of depression. Conclusions: The findings of the present study revealed that the expression of circUBE2K, which combines with HNRNPU to form the circUBE2K/HNRNPU complex, is increased in microglia after external stress, thus regulating the expression of the parental gene UBE2K and mediating the abnormal activation of microglia to induce neuroinflammation, promoting the development of MDD. These results indicate that circ-UBE2K plays a newly discovered role in the pathogenesis of depression.

Gut microbiota dysbiosis contributes to depression-like behaviors via hippocampal NLRP3-mediated neuroinflammation in a postpartum depression mouse model

Postpartum depression (PPD) is a severe mental disorder that affects approximately 10---20% of women after childbirth. The precise mechanism underlying PPD pathogenesis remains elusive, thus limiting the development of therapeutics. Gut microbiota dysbiosis is considered to contribute to major depressive disorder. However, the associations between gut microbiota and PPD remain unanswered. Here, we established a mouse PPD model by sudden ovarian steroid withdrawal after hormone-simulated pseudopregnancy-human (HSP-H) in ovariectomy (OVX) mouse. Ovarian hormone withdrawal induced depression-like and anxiety-like behaviors and an altered gut microbiota composition. Fecal microbiota transplantation (FMT) from PPD mice to antibiotic cocktail-treated mice induced depression-like and anxiety-like behaviors and neuropathological changes in the hippocampus of the recipient mice. FMT from healthy mice to PPD mice attenuated the depression-like and anxiety-like behaviors as well as the inflammation mediated by the NOD-like receptor protein (NLRP)-3/caspase-1 signaling pathway both in the gut and the hippocampus, increased fecal short-chain fatty acids (SCFAs) levels and alleviated gut dysbiosis with increased SCFA-producing bacteria and reduced Akkermansia in the PPD mice. Also, downregulation of NLRP3 in the hippocampus mitigated depression-like behaviors in PPD mice and overexpression of NLRP3 in the hippocampal dentate gyrus induced depression-like behaviors in naïve female mice. Intriguingly, FMT from healthy mice failed to alleviate depression-like behaviors in PPD mice with NLRP3 overexpression in the hippocampus. Our results highlighted the NLRP3 inflammasome as a key component within the microbiota-gut-brain axis, suggesting that targeting the gut microbiota may be a therapeutic strategy for PPD.

FMOD Alleviates Depression-Like Behaviors by Targeting the PI3K/AKT/mTOR Signaling After Traumatic Brain Injury

Depression frequently occurs following traumatic brain injury (TBI). However, the role of Fibromodulin (FMOD) in TBI-related depression is not yet clear. Previous studies have suggested FMOD as a potential key factor in TBI, yet its association with depression post-TBI and underlying mechanisms are not well understood. Serum levels of FMOD were measured in patients with traumatic brain injury using qPCR. The severity of depression was assessed using the self-depression scale (SDS). Neurological function, depressive state, and cognitive function in mice were assessed using the modified Neurological Severity Score (mNSS), forced swimming test (FST), tail suspension test (TST), Sucrose Preference Test (SPT), and morris water maze (MWM). The morphological features of mouse hippocampal synapses and neuronal dendritic spines were revealed through immunofluorescence, transmission electron microscopy, and Golgi-Cox staining. The protein expression levels of FMOD, MAP2, SYP, and PSD95, as well as the phosphorylation levels of the PI3K/AKT/mTOR signaling pathway, were detected through Western blotting. FMOD levels were decreased in TBI patients' serum. Overexpression of FMOD preserved neuronal function and alleviated depression-like behaviour, increased synaptic protein expression, and induced ultrastructural changes in hippocampal neurons. The increased phosphorylation of PI3K, AKT, and mTOR suggested the involvement of the PI3K/AKT/mTOR signaling pathway in FMOD's protective effects. FMOD exhibits potential as a therapeutic target for depression related to TBI, with its protective effects potentially mediated through the PI3K/AKT/mTOR signaling pathway.

Immunotherapy for depression: Recent insights and future targets

Depression stands as a prominent contributor to global disability, entailing an elevated risk of suicide. Substantial evidence supports the notion that immune dysregulation may play a role in the development of depression and impede responses to antidepressant treatments. Immune dysregulation may cause depression in susceptible individuals through raising inflammatory responses. Differences in immune cell types and the release of pro-inflammatory mediators are observed in the blood and cerebrospinal fluid of patients with major depressive disorder, which is associated with neuroimmune dysfunction. Therefore, the interaction of peripheral and central immune targets in depression needs to be understood. Urgent attention is required for the development of innovative therapeutics directed at modulating immune responses for the treatment of depression. This review delineates the immune mechanisms involved in the pathogenesis of depression, assesses the therapeutic potential of immune system targeting for depression treatment, and deliberates on the merits and constraints of employing immunotherapy in the management of depression.

Epigenetic mechanisms in depression: Implications for pathogenesis and treatment

The risk of depression is influenced by both genetic and environmental factors. It has been suggested that epigenetic mechanisms may mediate the risk of depression following exposure to adverse life events. Epigenetics encompasses stable alterations in gene expression that are controlled through transcriptional, post-transcriptional, translational, or post-translational processes, including DNA modifications, chromatin remodeling, histone modifications, RNA modifications, and non-coding RNA (ncRNA) regulation, without any changes in the DNA sequence. In this review, we explore recent research advancements in the realm of epigenetics concerning depression. Furthermore, we evaluate the potential of epigenetic changes as diagnostic and therapeutic biomarkers for depression.

Gut microbiota: A potential player in psychiatric symptoms during COVID-19

OBJECTIVES

This study aims to explore the potential interconnections among gut microbiota, COVID-19 infection, depression and anxiety disorder. Additionally, it tries to assess potential therapeutic interventions that may improve the dysbiosis of gut microbiota.

METHODS

To achieve these objectives, we reviewed existing literature, encompassing studies and critical reviews that intersect the domains of gut microbiota, COVID-19, depression and anxiety disorders.

RESULTS

The findings highlight a notable correlation between the dysbiosis of gut microbiota and psychiatric symptoms in the context of COVID-19. Specifically, there is a marked reduction in the populations of bacteria that generate anti-inflammatory short-chain fatty acids (SCFAs), alongside a rise in the prevalence of gut bacterial clusters linked to inflammatory processes. Furthermore, several potential treatment strategies were summarised for improving the dysbiosis.

CONCLUSIONS

Gut microbiota plays a significant role in psychiatric symptoms during COVID-19, which has significant implications for the study and prevention of psychiatric symptoms in major epidemic diseases.

Polyphenol Extracts from Ziziphus jujuba Mill. "Junzao" Attenuates Ulcerative Colitis by Inhibiting the NLRP3 and MAPKs Signaling Pathways and Regulating Gut Microbiota Homeostasis in Mice

SCOPE

Polyphenols are the major active substances in red jujube fruit, and their anti-inflammatory and antioxidant activities suggest their potential utility in the prevention of ulcerative colitis (UC).

METHODS AND RESULTS

In this study, the effect of polyphenol extracts from red jujube (Ziziphus jujuba Mill. "Junzao") (PERJ) on the dextron sulfate sodium (DSS)-induced UC mice is investigated. The result shows that PERJ effectively improves clinical symptoms, including food and water intake, the disease activity insex (DAI) and spleen index, and routine blood levels, and alleviates the shortening of the colon, in mice with DSS-induced UC. Meanwhile, PERJ remarkably decreases the expression of proinflammatory factors. Moreover, PERJ repairs intestinal barrier damage by increasing the expression level of mucin 2 and mucin 3, and the result is also confirmed in the histological assessment. Besides, the expression levels of Nod-like receptor family pyrin domain-containing 3 (NLRP3) and mitogen-activated protein kinase cascade (MAPKs) signaling pathway-related proteins are inhibited by the PERJ administration. Finally, 16S rRNA sequencing analyses reveal that PERJ reverses intestinal microbiota dysbiosis by enhancing the abundance of Firmicutes and decreasing that of Proteobacteria and Bacteroidetes.

CONCLUSION

PERJ probably inhibits the development of UC by suppressing the NLRP3 and MAPKs signaling pathways and regulating gut microbiota homeostasis, and can be considered as a potential resource for preventing UC.

Involvement of CircRNAs in regulating The "New Generation of Cancer Hallmarks": A Special Depiction on Hepatocellular Carcinoma

The concept of 'Hallmarks of Cancer' is an approach of reducing the enormous complexity of cancer to a set of guiding principles. As the underlying mechanism of cancer are portrayed, we find that we gain insight and additional aspects of the disease arise. The understanding of the tumor microenvironment (TME) brought a new dimension and led to the discovery of novel hallmarks such as senescent cells, non-mutational epigenetic reprogramming, polymorphic microbiomes and unlocked phenotypic plasticity. Circular RNAs (circRNAs) are single-stranded, covalently closed RNA molecules that are ubiquitous across all species. Recent studies on the circRNAs have highlighted their crucial function in regulating the formation of human malignancies through a range of biological processes. The primary goal of this review is to clarify the role of circRNAs in the most common form of liver cancer, hepatocellular carcinoma (HCC). This review also addressed the topic of how circRNAs affect HCC hallmarks, including the new generation hallmarks. Finally, the enormous applications that these rapidly expanding ncRNA molecules serve in the functional and molecular development of effective HCC diagnostic biomarkers and therapeutic targets.

The role of ncRNAs in depression

Depressive disorders have a significant impact on public health, and depression have an unsatisfactory recurrence rate and are challenging to treat. Non-coding RNAs (ncRNAs) are RNAs that do not code protein, which have been shown to be crucial for transcriptional regulation. NcRNAs are important to the onset, progress and treatment of depression because they regulate various physiological functions. This makes them distinctively useful as biomarkers for diagnosing and tracking responses to therapy among individuals with depression. It is important to seek out and summarize the research findings on the impact of ncRNAs on depression since significant advancements have been made in this area recently. Hence, we methodically outlined the findings of published researches on ncRNAs and depression, focusing on microRNAs. Above all, this review aims to improve our understanding of ncRNAs and provide new insights of the diagnosis and treatment of depression.

CircPTK2 may be associated with depressive-like behaviors by influencing miR-182-5p

BACKGROUND

Major depressive disorder (MDD) is a severe psychiatric disorder with uncertain causes. Recent studies have indicated correlations between circular RNAs (circRNAs) and psychiatric disorders. However, the potential role of circRNAs in MDD remains largely unknown.

METHODS

We investigated the expression and diagnostic significance of circRNA protein tyrosine kinase 2 (circPTK2) by recruiting 50 MDD patients and 40 healthy subjects. Additionally, chronic unpredictable mild stress (CUMS) mouse model was established in animal experiments. QRT-PCR was adopted for circPTK2 and miR-182-5p levels. To investigate the role of circPTK2 in MDD, we utilized microinjection of circPTK2 adeno-associated virus into the mouse hippocampus. Depressive-like behaviors of mice were assessed through forced swim test and open field test. Additionally, the interaction between circPTK2 and miR-182-5p was validated using a dual luciferase reporter assay.

RESULTS

Decreased expression of circPTK2 was found in peripheral blood mononuclear cells of MDD patients and in hippocampus of CUMS mice, which was useful for distinguishing MDD patients from healthy subjects. Notably, overexpression of circPTK2 was associated with depressive-like behaviors induced by CUMS. Further mechanism research demonstrated that circPTK2 functioned as the sponge for miR-182-5p, which may contribute to the beneficial effect of circPTK2.

CONCLUSION

Collectively, our findings suggest the participation of circPTK2 and its underlying mechanism in MDD, which might provide a potential target for MDD therapy.

Dual-directional regulation of spinal cord injury and the gut microbiota

There is increasing evidence that the gut microbiota affects the incidence and progression of central nervous system diseases via the brain-gut axis. The spinal cord is a vital important part of the central nervous system; however, the underlying association between spinal cord injury and gut interactions remains unknown. Recent studies suggest that patients with spinal cord injury frequently experience intestinal dysfunction and gut dysbiosis. Alterations in the gut microbiota can cause disruption in the intestinal barrier and trigger neurogenic inflammatory responses which may impede recovery after spinal cord injury. This review summarizes existing clinical and basic research on the relationship between the gut microbiota and spinal cord injury. Our research identified three key points. First, the gut microbiota in patients with spinal cord injury presents a key characteristic and gut dysbiosis may profoundly influence multiple organs and systems in patients with spinal cord injury. Second, following spinal cord injury, weakened intestinal peristalsis, prolonged intestinal transport time, and immune dysfunction of the intestine caused by abnormal autonomic nerve function, as well as frequent antibiotic treatment, may induce gut dysbiosis. Third, the gut microbiota and associated metabolites may act on central neurons and affect recovery after spinal cord injury; cytokines and the Toll-like receptor ligand pathways have been identified as crucial mechanisms in the communication between the gut microbiota and central nervous system. Fecal microbiota transplantation, probiotics, dietary interventions, and other therapies have been shown to serve a neuroprotective role in spinal cord injury by modulating the gut microbiota. Therapies targeting the gut microbiota or associated metabolites are a promising approach to promote functional recovery and improve the complications of spinal cord injury.

Role of circular RNAs and gut microbiome in gastrointestinal cancers and therapeutic targets

Gastrointestinal cancers are a huge worldwide health concern, which includes a wide variety of digestive tract cancers. Circular RNAs (circRNAs), a kind of non-coding RNA (ncRNAs), are a family of single-stranded, covalently closed RNAs that have become recognized as crucial gene expression regulators, having an impact on several cellular functions in cancer biology. The gut microbiome, which consists of several different bacteria, actively contributes to the regulation of host immunity, inflammation, and metabolism. CircRNAs and the gut microbiome interact significantly to greatly affect the growth of GI cancer. Several studies focus on the complex functions of circRNAs and the gut microbiota in GI cancers, including esophageal cancer, colorectal cancer, gastric cancer, hepatocellular cancer, and pancreatic cancer. It also emphasizes how changed circRNA expression profiles and gut microbiota affect pathways connected to malignancy as well as how circRNAs affect hallmarks of gastrointestinal cancers. Furthermore, circRNAs and gut microbiota have been recommended as biological markers for therapeutic targets as well as diagnostic and prognostic purposes. Targeting circRNAs and the gut microbiota for the treatment of gastrointestinal cancers is also being continued to study. Despite significant initiatives, the connection between circRNAs and the gut microbiota and the emergence of gastrointestinal cancers remains poorly understood. In this study, we will go over the most recent studies to emphasize the key roles of circRNAs and gut microbiota in gastrointestinal cancer progression and therapeutic options. In order to create effective therapies and plan for the future gastrointestinal therapy, it is important to comprehend the functions and mechanisms of circRNAs and the gut microbiota.

The role of gut microorganisms and metabolites in intracerebral hemorrhagic stroke: a comprehensive review

Intracerebral hemorrhagic stroke, characterized by acute hemorrhage in the brain, has a significant clinical prevalence and poses a substantial threat to individuals' well-being and productivity. Recent research has elucidated the role of gut microorganisms and their metabolites in influencing brain function through the microbiota-gut-brain axis (MGBA). This article provides a comprehensive review of the current literature on the common metabolites, short-chain fatty acids (SCFAs) and trimethylamine-N-oxide (TMAO), produced by gut microbiota. These metabolites have demonstrated the potential to traverse the blood-brain barrier (BBB) and directly impact brain tissue. Additionally, these compounds have the potential to modulate the parasympathetic nervous system, thereby facilitating the release of pertinent substances, impeding the buildup of inflammatory agents within the brain, and manifesting anti-inflammatory properties. Furthermore, this scholarly analysis delves into the existing dearth of investigations concerning the influence of gut microorganisms and their metabolites on cerebral functions, while also highlighting prospective avenues for future research.

YTHDF2 alleviates microglia activation via promoting circHIPK2 degradation

Microglial activation is a common cellular dysfunction in central nervous system inflammation, accompanied by abnormal expression of circular RNAs (circRNAs). YTHDF2, a N6-methyladenosine (m6A) reader, is known as a key element in RNA degradation. Here, lipolysaccharide induced microglia activation in mouse cortex and BV2 cells, accompanied by the decreased YTHDF2 and elevated circHIPK2. YTHDF2 overexpression or circHIPK2 knockdown in BV2 microglia inhibited the expressions of iNOS protein, IL-1β mRNA and IL-6 mRNA. Subsequent experiments revealed that YTHDF2 facilitated circHIPK2 degradation, thereby alleviating microglia activation. These findings suggest that YTHDF2 overexpression could serve as a therapeutic approach for inhibiting microglia activation.

The Landscape of Gut Microbiota and Its Metabolites: A Key to Understanding the Pathophysiology of Pattern in Chinese Medicine

Liver Stagnation and Spleen Deficiency (LSSD) is a Chinese Medicine (CM) pattern commonly observed in gastrointestinal (GI) diseases, yet its biological nature remains unknown. This limits the global use of CM medications for treating GI diseases. Recent studies emphasize the role of gut microbiota and their metabolites in the pathogenesis and treatment of LSSD-associated GI diseases. There is increasing evidence supporting that an altered gut microbiome in LSSD patients or animals contributes to GI and extra-intestinal symptoms and affects the effectiveness of CM therapies. The gut microbiota is considered to be an essential component of the biological basis of LSSD. This study aims to provide an overview of existing research findings and gaps for the pathophysiological study of LSSD from the gut microbiota perspective in order to understand the relationship between the CM pattern and disease progression and to optimize CM-based diagnosis, prevention, and therapy.