Mature astrocytes as source for astrocyte repopulation after deletion in the medial prefrontal cortex: Implications for depression.

The adult brain retains a high repopulation capacity of astrocytes after deletion, and both mature astrocytes in the neocortex and neural stem cells in neurogenic regions possess the potential to generate astrocytes. However, the origin and the repopulation dynamics of the repopulating astrocytes after deletion remain largely unclear. The number of astrocytes is reduced in the medial prefrontal cortex (mPFC) of patients with depression, and selective elimination of mPFC astrocytes is sufficient to induce depression-like behaviors in rodents. However, whether astrocyte repopulation capacity is impaired in depression is unknown. In this study, we used different transgenic mouse lines to genetically label different cell types and demonstrated that in the mPFC of normal adult mice of both sexes, mature astrocytes were a major source of the repopulating astrocytes after acute deletion induced by an astrocyte-specific toxin, L-alpha-aminoadipic acid (L-AAA), and astrocyte regeneration was accomplished within two weeks accompanied by reversal of depression-like behaviors. Furthermore, re-ablation of mPFC astrocytes post repopulation led to reappearance of depression-like behaviors. In adult male mice subjected to 14-day chronic restraint stress, a well-validated mouse model of depression, the number of mPFC astrocytes was reduced; however, the ability of mPFC astrocytes to repopulate after L-AAA-induced deletion was largely unaltered. Our study highlights a potentially beneficial role for repopulating astrocytes in depression and provides novel therapeutic insights into enhancing local mature astrocyte generation in depression.

PV network plasticity mediated by neuregulin1-ErbB4 signalling controls fear extinction.

Neuroplasticity in the medial prefrontal cortex (mPFC) is essential for fear extinction, the process of which forms the basis of the general therapeutic process used to treat human fear disorders. However, the underlying molecules and local circuit elements controlling neuronal activity and concomitant induction of plasticity remain unclear. Here we show that sustained plasticity of the parvalbumin (PV) neuronal network in the infralimbic (IL) mPFC is required for fear extinction in adult male mice and identify the involvement of neuregulin 1-ErbB4 signalling in PV network plasticity-mediated fear extinction. Moreover, regulation of fear extinction by basal medial amygdala (BMA)-projecting IL neurons is dependent on PV network configuration. Together, these results uncover the local molecular circuit mechanisms underlying mPFC-mediated top-down control of fear extinction, suggesting alterative therapeutic approaches to treat fear disorders.

Myocardin and pdx-1 synergistically induce hMSCs to differentiate into insulin secreting cells.

Mesenchymal stem cells (MSCs) have been reported as an attractive source for the generation of transplantable surrogate ß cells. The objective of this study was to investigate a new method to induce the differentiation of hMSCs into insulin secretion cells and to explore its molecular mechanisms. In this study, we investigated in vitro differentiation of hMSCs by overexpression of myocardin and pdx-1. Differentiated cells were evaluated by immunocytochemistry, reverse transcription-polymerase chain reaction (RT-PCR), quantificational real-time RT-PCR (qRT-PCR) and Western blotting. Furthermore, the molecular mechanisms were evaluated by chip assay, CO-IP and Luciferase assay. This study reported a new method to induce the differentiation of hMSCs into insulin secretion cells. The method is cotransduction of myocardin and pdx-1 for 7days. At the same time, we find myocardin and pdx-1 can form a complex to promote the transactivities of insulin by affecting the formation of the pdx-1/myocardin/SRF/CArG complex both in vitro and in vitro. The present study provided a simple and faithful in vitro model for further investigating the cell replacement therapy for diabetes.

Astrocytes in the Ventral Hippocampus Bidirectionally Regulate Innate and Stress-Induced Anxiety-Like Behaviors in Male Mice.

The mechanisms of anxiety disorders, the most common mental illness, remain incompletely characterized. The ventral hippocampus (vHPC) is critical for the expression of anxiety. However, current studies primarily focus on vHPC neurons, leaving the role for vHPC astrocytes in anxiety largely unexplored. Here, genetically encoded Ca2+ indicator GCaMP6m and in vivo fiber photometry calcium imaging are used to label vHPC astrocytes and monitor their activity, respectively, genetic and chemogenetic approaches to inhibit and activate vHPC astrocytes, respectively, patch-clamp recordings to measure glutamate currents, and behavioral assays to assess anxiety-like behaviors. It is found that vHPC astrocytic activity is increased in anxiogenic environments and by 3-d subacute restraint stress (SRS), a well-validated mouse model of anxiety disorders. Genetic inhibition of vHPC astrocytes exerts anxiolytic effects on both innate and SRS-induced anxiety-related behaviors, whereas hM3Dq-mediated chemogenetic or SRS-induced activation of vHPC astrocytes enhances anxiety-like behaviors, which are reversed by intra-vHPC application of the ionotropic glutamate N-methyl-d-aspartate receptor antagonists. Furthermore, intra-vHPC or systemic application of the N-methyl-d-aspartate receptor antagonist memantine, a U.S. FDA-approved drug for Alzheimer's disease, fully rescues SRS-induced anxiety-like behaviors. The findings highlight vHPC astrocytes as critical regulators of stress and anxiety and as potential therapeutic targets for anxiety and anxiety-related disorders.

A comparison of the impact on neuronal transcriptome and cognition of rAAV5 transduction with three different doses in the mouse hippocampus.

Introduction: Recombinant adeno-associated viruses (rAAVs) are widely used in genetic therapeutics. AAV5 has shown superior transduction efficiency, targeting neurons and glial cells in primate brains. Nonetheless, the comprehensive impact of AAV5 transduction on molecular and behavioral alterations remains unexplored. This study focuses on evaluating the effects of AAV5 transduction in the hippocampus, a critical region for memory formation and emotional processes. Methods: In this experiment, fluorescence-activated cell sorting (FACS) was utilized to isolate the mCherry-labeled pyramidal neurons in the hippocampus of CaMkIIα-cre mice following three different doses rAAV5-mCherry infusion after 3 weeks, which were then subjected to RNA sequencing (RNA-seq) to assess gene expression profiles. The cytokines concentration, mRNA expression, and glial response in hippocampi were confirmed by ELASA, digital droplet PCR and immunohistochemistry respectively. Locomotion and anxiety-like behaviors were elevated by Open Field Test and Elevated Plus Maze Test, while the Y-Maze were used to assessed spatial working memory. Recognition memory and fear responses were examined by the Novel Object Recognition Test and Fear Conditioning Test, respectively. Results: We found that 2.88 × 1010 v.g rAAV5 transduction significantly upregulated genes related to the immune response and apoptosis, and downregulated genes associated with mitochondrial function and synaptic plasticity in hippocampal pyramidal neurons, while did not induce neuronal loss and gliosis compared with 2.88 × 109 v.g and 2.88 × 108 v.g. Furthermore, the same doses impaired working memory and contextual fear memory, without effects on locomotion and anxiety-related behaviors. Discussion: Our findings highlight the detrimental impact of high-dose administration compared to median-dose or low-dose, resulting in increased neural vulnerability and impaired memory. Therefore, when considering the expression effectiveness of exogenous genes, it is crucial to also take potential side effects into account in clinical settings. However, the precise molecular mechanisms underlying these drawbacks of high-dose rAAV5-mCherry still require further investigation in future studies.

[MA Hui-fang's experience in age-related macular degeneration treated with acupuncture at Jingming (BL 1)].

The paper introduces professor MA Hui-fang's experience in age-related macular degeneration treated with acupuncture at Jingming (BL 1). It is believed that the basic pathogenesis of this disease refers to liver and kidney insufficiency and weakness of spleen qi. Based on the academic ideas of yang qi and meridian-collateral system, the treatment principle is proposed as "invigorating yang qi, replenishing the liver and kidney and nourishing the spleen and stomach". Regarding acupoint selection, Jingming (BL 1) is specially used, combined with the 4 front-mu points (Zhongwan [CV 12], Guanyuan [CV 4] and bilateral Tianshu [ST 25]), as well as the empirical points for eye diseases (Jingming [BL 1], Baihui [GV 20] and Zulinqi [GB 41]). Concerning to needling technique, shuci (transport needling), fenci (intermuscular needling) and yuandaoci (distal needling) are dominated. Eventually, a set of unique therapeutic method has been accumulated through professor MA Hui-fang's clinical practice in treatment of age-related macular degeneration.

[Effect of acupuncture on serum inflammatory cytokines and intestinal flora in rats with stress-induced gastric ulcer].

OBJECTIVE: To investigate the effect of acupuncture on serum inflammatory cytokines and intestinal flora in rats with stress-induced gastric ulcer (SGU), and to explore the mechanism of acupuncture in the treatment of SGU. METHODS: Sprague-Dawley rats were randomly divided into blank, model, acupuncture, and medication groups, with 7 rats in each group. Restraint water-immersion stress was used to establish the model of SGU. The rats in the acupuncture group were given acupuncture at "Zhongwan"(CV12) and bilateral "Zusanli"(ST36) for 20 min, once a day for 5 days, and those in the medication group were given 2 mL solution of Omeprazole enteric-coated tablets (0.2 mg/kg) by gavage, once a day for 5 days. The Guth method was used to calculate the gastric mucosa damage index, HE staining was used to observe the histopathological changes of the gastric mucosa, ELISA was used to measure the serum levels of interleukin-4 (IL-4) and interleukin-6 (IL-6), and 16S rDNA sequencing method was used to observe the change in intestinal flora. RESULTS: Compared with the blank group, the model group had a significant increase in gastric mucosa damage index (P<0.01), markedly pathological changes of the gastric mucosa shown by HE staining, a significant reduction in the content of serum IL-4 (P<0.01), and a significant increase in the content of serum IL-6 (P<0.01), as well as a significant reduction in Bacteroidetes and Firmicutes at the phylum level. Compared with the model group, the acupuncture group and the medication group had a significant reduction in gastric mucosa damage index (P<0.01, P<0.05). HE staining showed reduced pathological changes of the gastric mucosa, as well as a significant increase in the content of serum IL-4 (P<0.01, P<0.05) and a significant reduction in the content of serum IL-6 (P<0.01, P<0.05). As for the intestinal flora, there was a significant increase in Bacteroidetes. Compared with the medication group, the gastric mucosa damage index was decreased （P<0.05），the content of serum IL-4 was significantly increased （P<0.05）, while the content of serum IL-6 significantly decreased (P<0.05) in the acupuncture group. CONCLUSION: Acupuncture at CV12 and ST36 can down-regulate the content of serum IL-6, up-regulate the content of serum IL-4, maintain the relative homeostasis of inflammatory cytokines, and regulate the community structure of intestinal flora, and thus help to repair the damage of gastric mucosa.

[Effect of acupuncture on intestinal flora in rats with stress gastric ulcer].

OBJECTIVE: To observe the effect of acupuncture at "Baihui" (GV 20), "Zhongwan" (CV 12) and "Zusanli" (ST 36) on intestinal flora in rats with stress gastric ulcer (SGU) , and to explore the mechanism of acupuncture promoting SGU recovery. METHODS: Thirty-one SPF SD rats were randomly divided into a control group (7 rats), a model control group (8 rats), an acupuncture group (8 rats) and a medication group (8 rats). The rats in the model group, acupuncture group and medication group were selected to applied the improved restraint water-immersion stress method to establish the SGU model. After modeling, the rats in the control group and model group were fixed and restrained for 20 min every day for a total of 5 days; the rats in the acupuncture group were intervented with acupuncture at "Baihui" (GV 20), "Zhongwan" (CV 12) and "Zusanli" (ST 36), once a day, 20 min each time, and twisting needle for 30 s every 5 min for a total of 5 days; the rats in the medication group were gavaged by solution of omeprazole enteric-coated tablet (200 mg/mL), 2 mL for each rat, once a day. Guth method was used to calculate the gastric mucosal damage index (GMDI), HE staining was used to observe the pathological changes of gastric mucosa, and 16SrDNA identification was used to detect the structural abundance of intestinal flora. RESULTS: Compared with the control group, the GMDI of rats in the model group was increased (P<0.01), the gastric mucosal pathological changes were significant, and the intestinal flora richness index Chao1, Observed species and diversity index Shannon were all decreased (P<0.05), the diversity index Simpson was increased (P<0.05). Compared with the model group, the GMDI of rats in the acupuncture group and medication group was reduced (P<0.01, P<0.05), the gastric mucosal damage degree was reduced, and the intestinal flora richness index Chao1, Observed species and diversity index Shannon were all increased (P<0.05) and the diversity index Simpson decreased (P<0.05). Compared with the medication group, the GMDI of rats in the acupuncture group was reduced (P<0.01), the recovery of gastric mucosal injury was better than that of the medication group. CONCLUSION: Acupuncture can effectively improve gastric mucosal injury of SGU, and the mechanism may be related to increasing the diversity of intestinal flora and promoting the correction of the disordered intestinal flora.

Radiation-Induced Helium Bubbles in Metals.

Helium (He) bubbles are typical radiation defects in structural materials in nuclear reactors after high dose energetic particle irradiation. In the past decades, extensive studies have been conducted to explore the dynamic evolution of He bubbles under various conditions and to investigate He-induced hardening and embrittlement. In this review, we summarize the current understanding of the behavior of He bubbles in metals; overview the mechanisms of He bubble nucleation, growth, and coarsening; introduce the latest methods of He control by using interfaces in nanocrystalline metals and metallic multilayers; analyze the effects of He bubbles on strength and ductility of metals; and point out some remaining questions related to He bubbles that are crucial for design of advanced radiation-tolerant materials.

[Moxibustion improved gastric ulcer by reducing contents of corticotrophin-releasing hormone and adrenocorticotropic hormone in serum and hypothalamus-pituitary tissues in rats with stress-induced gastric ulcer].

OBJECTIVE: To observe the effect of moxibustion of "Zhongwan" (CV12) and "Zusanli" (ST36) on histopathological changes of the gastric mucosa and contents of corticotropin-releasing hormone(CRH) and adrenocorticotrophic hormone(ACTH) in the serum, hypothalamus and pituitary tissues in rats with stress-induced gastric ulcer(SGU), so as to reveal its mechanisms underlying improvement of SGU. METHODS: A total of 28 male SD rats were randomly divided into blank control, model, moxibustion, and medication groups, with 7 rats in each group. The SGU model was established by water immersion restraint stress for 3 h. Moxibustion was applied to "Zhongwan"(CV12) and bilateral "Zusanli" (ST36) for 20 min, once a day for 5 days, and rats of the medication group were treated by gavage of Omeprazole enteric-coated tablets (0.2 mg/kg) once a day for 5 days. The gastric mucosal damage index (ulcer index, UI) was measured to assess the injury severity according to Guth's me-thods. Histopathological changes of the gastric mucosa were determined by H．E. staining. The contents of CRH in serum and hypothalamus and ACTH in serum and pituitary gland tissue were assayed by using ELISA. RESULTS: Outcomes of H．E. staining showed gastric mucosal epithelia defect, disordered arrangement of glands, obvious mucosal hyperemia and edema, exudation of a large number of red blood cells, swelling of mucosal cells with necrosis of nuclei in the model group. These situations were relatively milder in the moxibustion and medication groups. After modeling, the UI, and the contents of CRH in the serum and hypotha-lamus, and ACTH in the serum and pituitary tissue were significantly increased in comparison with the blank control group (P<0.01). Following the intervention, the UI, and contents of CRH in the serum and hypothalamus, and ACTH in the serum and pituitary were all down-regulated in both medication and moxibustion groups relevant to the model group (P<0.05, P<0.01). The therapeutic effect of moxibustion was notably superior to that of medication in down-regulating serum CRH and ACTH (P<0.05). No significant differences were found between the medication and moxibustin interventions in lowering the UI, hypothalamic CRH and pituitary ACTH levels (P>0.05)．. CONCLUSION: Moxibustion can relieve gastric mucosal injury induced by stress in water immersion restraint stress rats, which may be associated with its effects in down-regulating the levels of CRH and ACTH in se-rum, hypothalamus and pituitary tissues (inhibition of activities of hypothalamic-pituitary-adrenocortical axis)．.

Molecular mechanism of hepatic stellate cell activation and antifibrotic therapeutic strategies.

Activation of hepatic stellate cells (HSCs) is the dominant event in liver fibrosis. The early events in the organization of HSC activation have been termed initiation. Initiation encompasses rapid changes in gene expression and phenotype that render the cells responsive to cytokines and other local stimuli. Cellular responses following initiation are termed perpetuation, which encompasses those cellular events that amplify the activated phenotype through enhanced growth factor expression and responsiveness. Multiple cells and cytokines play a part in the regulation of HSC activation. HSC activation consists of discrete phenotype responses, mainly proliferation, contractility, fibrogenesis, matrix degradation, chemotaxis and retinoid loss. Currently, antifibrotic therapeutic strategies include inhibition of HSC proliferation or stimulation of HSC apoptosis, downregulation of collagen production or promotion of its degradation, administration of cytokines, and infusion of mesenchymal stem cells. In this review, we summarize the latest advances in our understanding of the mechanisms of HSC activation and possible antifibrotic therapeutic strategies.

Indole-3-carbinol inhibits hepatic stellate cells proliferation by blocking NADPH oxidase/reactive oxygen species/p38 MAPK pathway.

During the course of liver fibrogenesis, hepatic stellate cell (HSC) proliferation as well as subsequent synthesis of excessive extracellular matrix components is known to be the central events. Thus, factors that could limit HSC proliferation are potential anti-fibrotic agents. The aim of this study was to investigate the effects of indole-3-carbinol (I3C), a nutritional component derived from Brassica family vegetables, on the proliferation of cultured HSC and to clarify the underline molecular mechanism. HSC-T6, an activated rat HSC line, was treated with I3C (50, 100 and 200 µM) for 24 h. The results indicated that I3C can significantly inhibit HSC proliferation in a concentration-dependent manner with or without platelet-derived growth factor-BB (PDGF-BB) stimulation (P<0.01). I3C could also block HSC in the G(0)/G(1) phase from entering the S phase. The expressions of α-smooth muscle actin in HSC treated with I3C, were significantly decreased at levels of protein and mRNA (P<0.01). In addition, the type I collagen level, cyclin D(1) and cyclin-dependent kinase 4 mRNA expressions, intracellular nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity and reactive oxygen species generation were significantly decreased by I3C (P<0.05). We also observed that the phosphorylated p38 MAPK in HSC-T6 was inhibited by I3C in a concentration-dependent manner; however, the phosphorylated ERK1/2 was unaltered. In conclusion, I3C could inhibit the proliferation of HSC by blocking the NADPH oxidase/reactive oxygen species/p38 MAPK signal pathway. These findings suggest that dietary I3C might play a novel role in prevention and treatment of chronic liver diseases.