OBJECTIVE: To investigate the protective effects of total saponins from Panax japonicus (TSPJ) against high-fat dietinduced testicular Sertoli cell junction damage in mice. METHODS: Forty male C57BL/6J mice were randomized into normal diet group, high-fat diet group, and low-dose (25 mg/kg) and high-dose (75 mg/kg) TSPJ treatment groups (n=10). The mice in the normal diet group were fed a normal diet, while the mice in the other groups were fed a high-fat diet. After TSPJ treatment via intragastric administration for 5 months, the testes and epididymis of the mice were collected for measurement of weight, testicular and epididymal indices and sperm parameters. HE staining was used for histological evaluation of the testicular tissues and measurement of seminiferous tubule diameter and seminiferous epithelium height. The expression levels of ZO-1, occludin, claudin11, N-cadherin, E-cadherin and β-catenin in Sertoli cells were detected with Western blot, and the localization and expression levels of ZO-1 and β-catenin in the testicular tissues were detected with immunofluorescence assay. The protein expressions of LC3B, p-AKT and p-mTOR in testicular Sertoli cells were detected using double immunofluorescence assay. RESULTS: Treatment with TSPJ significantly improved high-fat diet-induced testicular dysfunction by reducing body weight (P < 0.001), increasing testicular and epididymal indices (P < 0.05), and improving sperm concentration and sperm viability (P < 0.05). TSPJ ameliorated testicular pathologies and increased seminiferous epithelium height of the mice with high-fat diet feeding (P < 0.05) without affecting the seminiferous tubule diameter. TSPJ significantly increased the expression levels of ZO-1, occludin, N-cadherin, E-cadherin and β-catenin (P < 0.05) but did not affect claudin11 expression in the testicular tissues. Immunofluorescence assay showed that TSPJ significantly increased ZO-1 and β-catenin expression in the testicular tissues (P < 0.001), downregulated LC3B expression and upregulated p-AKT and p-mTOR expressions in testicular Sertoli cells. CONCLUSION TSPJ alleviates high-fat diet-induced damages of testicular Sertoli cell junctions and spermatogenesis possibly by activating the AKT/mTOR signaling pathway and inhibiting autophagy of testicular Sertoli cells.
Male ; Animals ; Mice ; Mice, Inbred C57BL ; Testis ; Sertoli Cells ; beta Catenin ; Diet, High-Fat ; Occludin ; Proto-Oncogene Proteins c-akt ; Seeds ; Cadherins ; Intercellular Junctions

OBJECTIVE: To investigate the mechanism by which fibroblasts with high WNT2b expression causes intestinal mucosa barrier disruption and promote the progression of inflammatory bowel disease (IBD). METHODS: Caco-2 cells were treated with 20% fibroblast conditioned medium or co-cultured with fibroblasts highly expressing WNT2b, with the cells without treatment with the conditioned medium and cells co-cultured with wild-type fibroblasts as the control groups. The changes in barrier permeability of Caco-2 cells were assessed by measuring transmembrane resistance and Lucifer Yellow permeability. In Caco-2 cells co-cultured with WNT2b-overexpressing or control intestinal fibroblasts, nuclear entry of β-catenin was detected with immunofluorescence assay, and the expressions of tight junction proteins ZO-1 and E-cadherin were detected with Western blotting. In a C57 mouse model of dextran sulfate sodium (DSS)-induced IBD-like enteritis, the therapeutic effect of intraperitoneal injection of salinomycin (5 mg/kg, an inhibitor of WNT/β-catenin signaling pathway) was evaluated by observing the changes in intestinal inflammation and detecting the expressions of tight junction proteins. RESULTS: In the coculture system, WNT2b overexpression in the fibroblasts significantly promoted nuclear entry of β-catenin (P < 0.01) and decreased the expressions of tight junction proteins in Caco-2 cells; knockdown of FZD4 expression in Caco-2 cells obviously reversed this effect. In DSS-treated mice, salinomycin treatment significantly reduced intestinal inflammation and increased the expressions of tight junction proteins in the intestinal mucosa. CONCLUSION Intestinal fibroblasts overexpressing WNT2b causes impairment of intestinal mucosal barrier function and can be a potential target for treatment of IBD.
Humans ; Mice ; Animals ; Caco-2 Cells ; beta Catenin/metabolism* ; Culture Media, Conditioned/pharmacology* ; Tight Junctions/metabolism* ; Intestinal Mucosa ; Inflammatory Bowel Diseases ; Tight Junction Proteins/metabolism* ; Inflammation/metabolism* ; Fibroblasts/metabolism* ; Mice, Inbred C57BL ; Glycoproteins/metabolism* ; Wnt Proteins/pharmacology* ; Frizzled Receptors/metabolism*

Differing from other subtypes of inhibitory interneuron, chandelier or axo-axonic cells form depolarizing GABAergic synapses exclusively onto the axon initial segment (AIS) of targeted pyramidal cells (PCs). However, the debate whether these AIS-GABAergic inputs produce excitation or inhibition in neuronal processing is not resolved. Using realistic NEURON modeling and electrophysiological recording of cortical layer-5 PCs, we quantitatively demonstrate that the onset-timing of AIS-GABAergic input, relative to dendritic excitatory glutamatergic inputs, determines its bi-directional regulation of the efficacy of synaptic integration and spike generation in a PC. More specifically, AIS-GABAergic inputs promote the boosting effect of voltage-activated Na⁺ channels on summed synaptic excitation when they precede glutamatergic inputs by >15 ms, while for nearly concurrent excitatory inputs, they primarily produce a shunting inhibition at the AIS. Thus, our findings offer an integrative mechanism by which AIS-targeting interneurons exert sophisticated regulation of the input-output function in targeted PCs.
Axon Initial Segment ; Axons/physiology* ; Neurons ; Synapses/physiology* ; Pyramidal Cells/physiology* ; Interneurons/physiology* ; Action Potentials/physiology*

BACKGROUND: Imatinib mesylate (IM) resistance is an emerging problem for chronic myeloid leukemia (CML). Previous studies found that connexin 43 (Cx43) deficiency in the hematopoietic microenvironment (HM) protects minimal residual disease (MRD), but the mechanism remains unknown. METHODS: Immunohistochemistry assays were employed to compare the expression of Cx43 and hypoxia-inducible factor 1α (HIF-1α) in bone marrow (BM) biopsies of CML patients and healthy donors. A coculture system of K562 cells and several Cx43-modified bone marrow stromal cells (BMSCs) was established under IM treatment. Proliferation, cell cycle, apoptosis, and other indicators of K562 cells in different groups were detected to investigate the function and possible mechanism of Cx43. We assessed the Ca 2+ -related pathway by Western blotting. Tumor-bearing models were also established to validate the causal role of Cx43 in reversing IM resistance. RESULTS: Low levels of Cx43 in BMs were observed in CML patients, and Cx43 expression was negatively correlated with HIF-1α. We also observed that K562 cells cocultured with BMSCs transfected with adenovirus-short hairpin RNA of Cx43 (BMSCs-shCx43) had a lower apoptosis rate and that their cell cycle was blocked in G0/G1 phase, while the result was the opposite in the Cx43-overexpression setting. Cx43 mediates gap junction intercellular communication (GJIC) through direct contact, and Ca 2+ is the key factor mediating the downstream apoptotic pathway. In animal experiments, mice bearing K562, and BMSCs-Cx43 had the smallest tumor volume and spleen, which was consistent with the in vitro experiments. CONCLUSIONS Cx43 deficiency exists in CML patients, promoting the generation of MRD and inducing drug resistance. Enhancing Cx43 expression and GJIC function in the HM may be a novel strategy to reverse drug resistance and promote IM efficacy.
Animals ; Humans ; Mice ; Apoptosis ; Bone Marrow Cells ; Cell Communication ; Connexin 43/genetics* ; Gap Junctions/metabolism* ; Imatinib Mesylate/therapeutic use* ; K562 Cells ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology* ; Mesenchymal Stem Cells/metabolism* ; Tumor Microenvironment ; Calcium/metabolism*

The axon initial segment (AIS) is a highly specialized axonal compartment where the action potential is initiated. The heterogeneity of AISs has been suggested to occur between interneurons and pyramidal neurons (PyNs), which likely contributes to their unique spiking properties. However, whether the various characteristics of AISs can be linked to specific PyN subtypes remains unknown. Here, we report that in the prelimbic cortex (PL) of the mouse, two types of PyNs with axon projections either to the contralateral PL or to the ipsilateral basal lateral amygdala, possess distinct AIS properties reflected by morphology, ion channel expression, action potential initiation, and axo-axonic synaptic inputs from chandelier cells. Furthermore, projection-specific AIS diversity is more prominent in the superficial layer than in the deep layer. Thus, our study reveals the cortical layer- and axon projection-specific heterogeneity of PyN AISs, which may endow the spiking of various PyN types with exquisite modulation.
Mice ; Animals ; Axon Initial Segment ; Synapses/physiology* ; Pyramidal Cells/physiology* ; Cerebral Cortex ; Axons/physiology*

BACKGROUND: Sjögren's syndrome (SS) is an autoimmune disorder characterized by sicca syndrome and/or systemic manifestations. The treatment is still challenging. This study aimed to explore the therapeutic role and mechanism of exosomes obtained from the supernatant of stem cells derived from human exfoliated deciduous teeth (SHED-exos) in sialadenitis caused by SS. METHODS: SHED-exos were administered to the submandibular glands (SMGs) of 14-week-old non-obese diabetic (NOD) mice, an animal model of the clinical phase of SS, by local injection or intraductal infusion. The saliva flow rate was measured after pilocarpine intraperitoneal injection in 21-week-old NOD mice. Protein expression was examined by western blot analysis. Exosomal microRNA (miRNAs) were identified by microarray analysis. Paracellular permeability was evaluated by transepithelial electrical resistance measurement. RESULTS: SHED-exos were injected into the SMG of NOD mice and increased saliva secretion. The injected SHED-exos were taken up by glandular epithelial cells, and further increased paracellular permeability mediated by zonula occluden-1 (ZO-1). A total of 180 exosomal miRNAs were identified from SHED-exos, and Kyoto Encyclopedia of Genes and Genomes analysis suggested that the phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt) pathway might play an important role. SHED-exos treatment down-regulated phospho-Akt (p-Akt)/Akt, phospho-glycogen synthase kinase 3β (p-GSK-3β)/GSK-3β, and Slug expressions and up-regulated ZO-1 expression in SMGs and SMG-C6 cells. Both the increased ZO-1 expression and paracellular permeability induced by SHED-exos were abolished by insulin-like growth factor 1, a PI3K agonist. Slug bound to the ZO-1 promoter and suppressed its expression. For safer and more effective clinical application, SHED-exos were intraductally infused into the SMGs of NOD mice, and saliva secretion was increased and accompanied by decreased levels of p-Akt/Akt, p-GSK-3β/GSK-3β, and Slug and increased ZO-1 expression. CONCLUSION Local application of SHED-exos in SMGs can ameliorate Sjögren syndrome-induced hyposalivation by increasing the paracellular permeability of glandular epithelial cells through Akt/GSK-3β/Slug pathway-mediated ZO-1 expression.
Mice ; Animals ; Humans ; Sjogren's Syndrome/therapy* ; Proto-Oncogene Proteins c-akt/metabolism* ; Tight Junctions/metabolism* ; Glycogen Synthase Kinase 3 beta ; Mice, Inbred NOD ; Phosphatidylinositol 3-Kinases/metabolism* ; Exosomes/metabolism* ; Xerostomia ; Phosphatidylinositol 3-Kinase ; MicroRNAs/genetics*

Objective: To study the mechanisms of cold exposure mediated ileum mechanical barrier injury in mice. Methods: Twenty mice were randomly divided into the control and cold exposure groups. Both the control and cold exposure groups were placed in the climate room with (24±2)℃ and 40% humidity. The mice in the cold exposure group were moved to the climate room at (4±2)℃ every day for 3 hours for three consecutive weeks. Three weeks later, the ileum tissues of mice were collected. Changes in ileum tissue structure were observed by hematoxylin-eosin staining and Masson staining. The related protein expression levels of the tight junction, inflammatory cytokines, and the NF-κB pathway were detected by Western blot. Results: Compared with the control group, the circular muscle layer of the ileum in cold exposed mice became thin, a large number of inflammatory cells infiltrated, the length of villi became short, the depth of recess was increased, and tissue fibrosis appeared. The expression levels of ideal tight junction-associated proteins in cold exposed mice were decreased significantly (P＜0.05), while the protein expression levels of IL-1β, IL-6 and phosphorescent p65 were increased significantly (P＜0.05). Conclusion: Cold exposure can damage the tight junction of the mouse ileum, destroy the integrity of the mechanical barrier and activate the NF-κB signaling pathway to promote the occurrence of the inflammatory response.
Animals ; Cytokines/metabolism* ; Ileum/metabolism* ; Intestinal Mucosa ; Mice ; NF-kappa B/metabolism* ; Tight Junctions/metabolism*

CaMKII is essential for long-term potentiation (LTP), a process in which synaptic strength is increased following the acquisition of information. Among the four CaMKII isoforms, γCaMKII is the one that mediates the LTP of excitatory synapses onto inhibitory interneurons (LTP_E→I). However, the molecular mechanism underlying how γCaMKII mediates LTP_E→I remains unclear. Here, we show that γCaMKII is highly enriched in cultured hippocampal inhibitory interneurons and opts to be activated by higher stimulating frequencies in the 10-30 Hz range. Following stimulation, γCaMKII is translocated to the synapse and becomes co-localized with the postsynaptic protein PSD-95. Knocking down γCaMKII prevents the chemical LTP-induced phosphorylation and trafficking of AMPA receptors (AMPARs) in putative inhibitory interneurons, which are restored by overexpression of γCaMKII but not its kinase-dead form. Taken together, these data suggest that γCaMKII decodes NMDAR-mediated signaling and in turn regulates AMPARs for expressing LTP in inhibitory interneurons.
Calcium-Calmodulin-Dependent Protein Kinase Type 2/metabolism* ; Hippocampus/metabolism* ; Interneurons/physiology* ; Long-Term Potentiation/physiology* ; N-Methylaspartate/metabolism* ; Receptors, AMPA/physiology* ; Receptors, N-Methyl-D-Aspartate/metabolism* ; Synapses/physiology*

Neurons are highly interwoven to form intricate neural circuits that underlie the diverse functions of the brain. Dissecting the anatomical organization of neural circuits is key to deciphering how the brain processes information, produces thoughts, and instructs behaviors. Over the past decades, recombinant viral vectors have become the most commonly used tracing tools to define circuit architecture. In this review, we introduce the current categories of viral tools and their proper application in circuit tracing. We further discuss some advances in viral tracing strategy and prospective innovations of viral tools for future study.
Synapses/physiology* ; Prospective Studies ; Neurons/physiology* ; Genetic Vectors ; Brain/physiology* ; Neural Pathways/physiology*

Alzheimer Disease/pathology* ; Animals ; C9orf72 Protein/metabolism* ; Mice ; Microglia/pathology* ; Neuronal Plasticity ; Neurons/pathology* ; Synapses/pathology*