Expression of semaphorin-3A in the joint and role in osteoarthritis.

Osteoarthritis (OA) is characterised by the deterioration of cartilage in the joints and pain. We hypothesise that semaphorin-3A (sema-3A), a chemorepellent for sensory nerves, plays a role in joint degradation and pain. We used the mechanical joint loading (MJL) model of OA to investigate sema-3A expression in the joint and examine its association with the development of OA and pain. We also analyse its effect on chondrocyte differentiation using the ATDC5 cell line. We demonstrate that sema-3A is present in most tissues in the healthy joint and its expression increases in highly innervated tissues, such as cruciate ligaments, synovial lining and subchondral bone, in loaded compared to nonloaded control joints. In contrast, sema-3A expression in cartilage was decreased in the severe OA induced by the application of high loads. There was a significant increase in circulating sema-3A, 6 weeks after MJL compared to the nonloaded mice. mRNA for sema-3A and its receptor Plexin A1 were upregulated in the dorsal root ganglia of mice submitted to MJL. These increases were supressed by zoledronate, an inhibitor of bone pain. Sema-3A was expressed at all stages of Chondrocyte maturation and, when added exogenously, stimulated expression of markers of chondrocyte differentiation. This indicates that sema-3A could affect joint tissues distinctively during the development of OA. In highly innervated joint tissues, sema-3A could control innervation and/or induce pain-associated neuronal changes. In cartilage, sema-3A could favour its degeneration by modifying chondrocyte differentiation.

Naringin activates semaphorin 3A to ameliorate TGF-ß-induced endothelial-to-mesenchymal transition related to atrial fibrillation.

The loss of semaphorin 3A (Sema3A), which is related to endothelial-to-mesenchymal transition (EndMT) in atrial fibrosis, is implicated in the pathogenesis of atrial fibrillation (AF). To explore the mechanisms by which EndMT affects atrial fibrosis and assess the potential of a Sema3A activator (naringin) to prevent atrial fibrosis by targeting transforming growth factor-beta (TGF-ß)-induced EndMT, we used human atria, isolated human atrial endocardial endothelial cells (AEECs), and used transgenic mice expressing TGF-ß specifically in cardiac tissues (TGF-ß transgenic mice). We evaluated an EndMT marker (Twist), a proliferation marker (proliferating cell nuclear antigen; PCNA), and an endothelial cell (EC) marker (CD31) through triple immunohistochemistry and confirmed that both EndMT and EC proliferation contribute to atrial endocardial fibrosis during AF in TGF-ß transgenic mice and AF patient tissue sections. Additionally, we investigated the impact of naringin on EndMT and EC proliferation in AEECs and atrial fibroblasts. Naringin exhibited an antiproliferative effect, to which AEECs were more responsive. Subsequently, we downregulated Sema3A in AEECs using small interfering RNA to clarify a correlation between the reduction in Sema3A and the elevation of EndMT markers. Naringin treatment induced the expression of Sema3A and a concurrent decrease in EndMT markers. Furthermore, naringin administration ameliorated AF and endocardial fibrosis in TGF-ß transgenic mice by stimulating Sema3A expression, inhibiting EndMT markers, reducing atrial fibrosis, and lowering AF vulnerability. This suggests therapeutic potential for naringin in AF treatment.

Insular cortex stimulation alleviates neuropathic pain through changes in the expression of collapsin response mediator protein 2 involved in synaptic plasticity.

In recent studies, brain stimulation has shown promising potential to alleviate chronic pain. Although studies have shown that stimulation of pain-related brain regions can induce pain-relieving effects, few studies have elucidated the mechanisms of brain stimulation in the insular cortex (IC). The present study was conducted to explore the changes in characteristic molecules involved in pain modulation mechanisms and to identify the changes in synaptic plasticity after IC stimulation (ICS). Following ICS, pain-relieving behaviors and changes in proteomics were explored. Neuronal activity in the IC after ICS was observed by optical imaging. Western blotting was used to validate the proteomics data and identify the changes in the expression of glutamatergic receptors associated with synaptic plasticity. Experimental results showed that ICS effectively relieved mechanical allodynia, and proteomics identified specific changes in collapsin response mediator protein 2 (CRMP2). Neuronal activity in the neuropathic rats was significantly decreased after ICS. Neuropathic rats showed increased expression levels of phosphorylated CRMP2, alpha amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor (AMPAR), and N-methyl-d-aspartate receptor (NMDAR) subunit 2B (NR2B), which were inhibited by ICS. These results indicate that ICS regulates the synaptic plasticity of ICS through pCRMP2, together with AMPAR and NR2B, to induce pain relief.

Sema3A ameliorates the pathological progression of osteoarthritis by modulating mitochondrial damage in chondrocytes.

Osteoarthritis (OA) is a major disease that causes disability in middle-aged and elderly people. A comprehensive understanding of its pathogenesis is of great significance in finding new clinical diagnosis and treatment schemes. The role of Semaphorin 3A (Sema3A) in OS has attracted attention recently, and the purpose of this study is to analyze the mechanisms underlying its impact on OS. First, a rat model of OS was established. Hematoxylin-eosin (HE) and TUNEL staining showed that the modeled rats presented typical pathological manifestations of OS, confirming the success of the modeling. Sema3A was significantly underexpressed in OS rats. Subsequently, Sema3A abnormal expression vectors were constructed to intervene in chondrocytes isolated from OS rats. It was found that the proliferation of chondrocytes was decreased, the apoptosis was increased, and the mitochondrial damage and autophagy were intensified after silencing Sema3A expression, while the above pathological processes were reversed when Sema3A expression was increased. In conclusion, Sema3A has an important influence on the pathological progression of OS, and molecular therapies targeting to increase Sema3A expression may become a new treatment for OS in the future.

Reduced expression of semaphorin 3A in osteoclasts causes lymphatic expansion in a Gorham-Stout disease (GSD) mouse model. / ç ´éª¨ç»†èƒžä¸­ä¿¡å·ç´ 3Aè¡¨è¾¾çš„å‡å°‘å¯¼è‡´å°é¼ GSDæ¨¡åž‹ä¸­æ·‹å·´ç®¡æ‰©å¼ .

Gorham-Stout disease (GSD) is a sporadic chronic disease characterized by progressive bone dissolution, absorption, and disappearance along with lymphatic vessel infiltration in bone-marrow cavities. Although the osteolytic mechanism of GSD has been widely studied, the cause of lymphatic hyperplasia in GSD is rarely investigated. In this study, by comparing the RNA expression profile of osteoclasts (OCs) with that of OC precursors (OCPs) by RNA sequencing, we identified a new factor, semaphorin 3A (Sema3A), which is an osteoprotective factor involved in the lymphatic expansion of GSD. Compared to OCPs, OCs enhanced the growth, migration, and tube formation of lymphatic endothelial cells (LECs), in which the expression of Sema3A is low compared to that in OCPs. In the presence of recombinant Sema3A, the growth, migration, and tube formation of LECs were inhibited, further confirming the inhibitory effect of Sema3A on LECs in vitro. Using an LEC-induced GSD mouse model, the effect of Sema3A was examined by injecting lentivirus-expressing Sema3A into the tibiae in vivo. We found that the overexpression of Sema3A in tibiae suppressed the expansion of LECs and alleviated bone loss, whereas the injection of lentivirus expressing Sema3A short hairpin RNA (shRNA) into the tibiae caused GSD-like phenotypes. Histological staining further demonstrated that OCs decreased and osteocalcin increased after Sema3A lentiviral treatment, compared with the control. Based on the above results, we propose that reduced Sema3A in OCs is one of the mechanisms contributing to the pathogeneses of GSD and that expressing Sema3A represents a new approach for the treatment of GSD.

Balancing act of small GTPases downstream of plexin-A4 signaling motifs promotes dendrite elaboration in mammalian cortical neurons.

The precise development of neuronal morphologies is crucial to the establishment of synaptic circuits and, ultimately, proper brain function. Signaling by the axon guidance cue semaphorin 3A (Sema3A) and its receptor complex of neuropilin-1 and plexin-A4 has multifunctional outcomes in neuronal morphogenesis. Downstream activation of the RhoGEF FARP2 through interaction with the lysine-arginine-lysine motif of plexin-A4 and consequent activation of the small GTPase Rac1 promotes dendrite arborization, but this pathway is dispensable for axon repulsion. Here, we investigated the interplay of small GTPase signaling mechanisms underlying Sema3A-mediated dendritic elaboration in mouse layer V cortical neurons in vitro and in vivo. Sema3A promoted the binding of the small GTPase Rnd1 to the amino acid motif lysine-valine-serine (LVS) in the cytoplasmic domain of plexin-A4. Rnd1 inhibited the activity of the small GTPase RhoA and the kinase ROCK, thus supporting the activity of the GTPase Rac1, which permitted the growth and branching of dendrites. Overexpression of a dominant-negative RhoA, a constitutively active Rac1, or the pharmacological inhibition of ROCK activity rescued defects in dendritic elaboration in neurons expressing a plexin-A4 mutant lacking the LVS motif. Our findings provide insights into the previously unappreciated balancing act between Rho and Rac signaling downstream of specific motifs in plexin-A4 to mediate Sema3A-dependent dendritic elaboration in mammalian cortical neuron development.

Sema3A secreted by sensory nerve induces bone formation under mechanical loads.

Bone formation and deposition are initiated by sensory nerve infiltration in adaptive bone remodeling. Here, we focused on the role of Semaphorin 3A (Sema3A), expressed by sensory nerves, in mechanical loads-induced bone formation and nerve withdrawal using orthodontic tooth movement (OTM) model. Firstly, bone formation was activated after the 3rd day of OTM, coinciding with a decrease in sensory nerves and an increase in pain threshold. Sema3A, rather than nerve growth factor (NGF), highly expressed in both trigeminal ganglion and the axons of periodontal ligament following the 3rd day of OTM. Moreover, in vitro mechanical loads upregulated Sema3A in neurons instead of in human periodontal ligament cells (hPDLCs) within 24 hours. Furthermore, exogenous Sema3A restored the suppressed alveolar bone formation and the osteogenic differentiation of hPDLCs induced by mechanical overload. Mechanistically, Sema3A prevented overstretching of F-actin induced by mechanical overload through ROCK2 pathway, maintaining mitochondrial dynamics as mitochondrial fusion. Therefore, Sema3A exhibits dual therapeutic effects in mechanical loads-induced bone formation, both as a pain-sensitive analgesic and a positive regulator for bone formation.

Boric Acid Alleviates Gastric Ulcer by Regulating Oxidative Stress and Inflammation-Related Multiple Signaling Pathways.

Oxidative stress and inflammation have pivotal roles in gastric ulcer development caused by alcohol consumption. Trace element boric acid taken into the human and animal body from dietary sources displays strong antioxidant and anti-inflammatory functions. However, the mechanisms underlying these actions of boric acid remain unclear, and its effectiveness in preventing gastric lesions is unknown. Therefore, the present study was undertaken to evaluate the protective effects of boric acid in alcohol-induced gastric ulcer and elucidate its potential mechanisms. Gastric ulcer was induced by 75% oral ethanol administration in rats, and the effectiveness of prophylactic boric acid treatment at 100 mg/kg concentration was assessed by histopathological examination, ELISA assay and qRT-PCR. Gross macroscopic and histopathological evaluations revealed that boric acid alleviated gastric mucosal lesions. Boric acid decreased reactive oxygen species (ROS) and malondialdehyde (MDA) concentration and the overall oxidation state of the body while improving antioxidant status. It reduced the concentration of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6). The mRNA expression of JAK2 and STAT3 was decreased while the expression of AMPK was increased with boric acid pretreatment. Moreover, Sema3A and PlexinA1 levels were elevated upon boric acid pretreatment, and homocysteine levels were reduced. Our results demonstrated that boric acid protects gastric mucosa from ethanol-induced damage by regulating oxidative and inflammatory responses. In addition, our findings suggested that the gastroprotective activity of boric acid could be attributed to its regulatory function in the IL-6/JAK2/STAT3 signaling modulated by AMPK and that Sema3A/PlxnA1 axis and homocysteine are potentially involved in this process.

Swimming alters some proteins of skeletal muscle tissue in rats with Alzheimer-like phenotype.

OBJECTIVES: Exercise training plays a significant role in preventing the destruction of central nerve neurons and muscle atrophy. The purpose of the present study was to investigate the effect of a period of swimming training on the expression of Neural cell adhesion molecule (NCAM), Semaphorin 3A (SEMA3A), and Profilin-1 (PFN1) proteins in the gastrocnemius muscle of Alzheimer-like phenotype rats. METHODS & MATERIALS: 32 Wistar males were (6 weeks of age) divided into four groups: Healthy Control (HC), Alzheimer-like phenotype's Control (AC), Healthy Training (HT), and Alzheimer-like phenotype's Training (AT). Alzheimer-like phenotypes were induced by beta-amyloid injection in the hippocampus. The training program consisted of 20 swimming sessions. Gastrocnemius muscle was removed after the intervention, and NCAM, SEMA3A, and PFN1 proteins were measured by the immunohistoflorescent method. RESULTS: The results showed that SEMA3A was increased (p = 0.001), and NCAM (p = 0.001), and PFN1 (p = 0.001) were decreased in AC compared to the HC group. Also, the results showed that NCAM (p = 0.001) and Pfn1 (p = 0.002) increased in the HT group compared to HC, and the NCAM (p = 0.001) and Pfn1 (p = 0.002) in AT group compared to AC (p = 0.001) increased significantly, while SEMA3A was reduced in the HT group compared to HC (p = 0.001) and AT group compared to AC (p = 0.001) CONCLUSION: Swimming effectively improves axon regeneration and neuronal formation in motor neurons and, therefore, can be an effective intervention to prevent and control the complications of Alzheimer-like phenotype.

Modulation of semaphorin 3C & 4D expression in cancerous tissues from individuals with laryngeal squamous cell carcinoma.

BACKGROUND OBJECTIVES: Semaphorins were initially characterized as axon guidance factors but were subsequently implicated in the regulation of immune responses, angiogenesis, organ formation and a variety of other physiological and developmental functions. Various semaphorins enhance or inhibit tumour progression through different mechanisms. The objective of this study was to assess the expression of various semaphorins and vascular endothelial growth factor (VEGF) gene transcripts as well as the serum level of Sema3A in individuals with laryngeal squamous cell carcinoma (LSCC). METHODS: Tissue expression of Sema3A, Sema3C, Sema4D, Sema6D and VEGF was determined in both tumour tissues and tissues around the tumour from 30 individuals with pathologically confirmed LSCC using quantitative real-time PCR. Furthermore, the serum level of Sema3A in these individuals was assessed using enzyme-linked immunosorbent assay. RESULTS: Sema3C gene transcript showed a significant increase (P=0.001), while Sema4D was observed with a significant decrease in tumour samples compared to non-tumoural tissues (P≤0.01). The expression of the Sema3C gene was found to be associated with the stage of LSCC tumour as it was statistically significant for tumours with stage IV (P<0.01). The serum level of Sema3A was not found to be significant between cases and controls. INTERPRETATION CONCLUSIONS: Increased expression of Sema3C but decreased expression of Sema4D in tumour tissue of LSCC may introduce these two growth factors as crucial mediators orchestrating tumour growth in individuals with LSCC. This result could open a new vision for the treatment of this malignancy.

The semaphorin 3A/neuropilin-1 pathway promotes clonogenic growth of glioblastoma via activation of TGF-ß signaling.

Glioblastoma (GBM) is the most lethal brain cancer with a dismal prognosis. Stem-like GBM cells (GSCs) are a major driver of GBM propagation and recurrence; thus, understanding the molecular mechanisms that promote GSCs may lead to effective therapeutic approaches. Through in vitro clonogenic growth-based assays, we determined mitogenic activities of the ligand molecules that are implicated in neural development. We have identified that semaphorin 3A (Sema3A), originally known as an axon guidance molecule in the CNS, promotes clonogenic growth of GBM cells but not normal neural progenitor cells (NPCs). Mechanistically, Sema3A binds to its receptor neuropilin-1 (NRP1) and facilitates an interaction between NRP1 and TGF-ß receptor 1 (TGF-ßR1), which in turn leads to activation of canonical TGF-ß signaling in both GSCs and NPCs. TGF-ß signaling enhances self-renewal and survival of GBM tumors through induction of key stem cell factors, but it evokes cytostatic responses in NPCs. Blockage of the Sema3A/NRP1 axis via shRNA-mediated knockdown of Sema3A or NRP1 impeded clonogenic growth and TGF-ß pathway activity in GSCs and inhibited tumor growth in vivo. Taken together, these findings suggest that the Sema3A/NRP1/TGF-ßR1 signaling axis is a critical regulator of GSC propagation and a potential therapeutic target for GBM.

Pure platelet-rich plasma promotes semaphorin-3A expression: a novel insight to ameliorate intervertebral disk degeneration in vitro.

INTRODUCTION: Intervertebral disk degeneration (IVDD) can be effectively treated using platelet-rich plasma (PRP). While the exact process is fully understood, it is believed that using pure PRP (P-PRP) without leukocytes is a better option for preventing IVDD. Semaphorin-3A (Sema3A), an inhibitor of angiogenesis and innervation, is essential for preserving IVDD's homeostasis. Whether PRP prevents IVDD by modifying Sema3A has yet to receive much research. This work aims to clarify how P-PRP affects Sema3A when IVDD develops in vitro. METHODS: Nucleus pulposus cells (NPCs) isolated from 8-week-old male Sprague-Dawley rats were exposed to 10 ng/ml IL-1ß and then treated with P-PRP or leukocyte platelet-rich plasma (L-PRP) in vitro, followed by measuring cell proliferation, apoptosis and microstructures, inflammatory gene and Sema3A expression, as well as anabolic and catabolic protein expression by immunostaining, quantitative real-time polymerase chain reaction (qPCR), western blot, and enzyme-linked immunosorbent assay (ELISA). RESULTS: In comparison with L-PRP, P-PRP had a higher concentration of growth factors but a lower concentration of inflammatory substances. P-PRP increased the proliferation of NPCs, while IL-1 relieved the amount of apoptosis due to its intervention. Anabolic genes, aggrecan, and collagen II had higher expression levels. MMP-3 and ADAMTS-4, two catabolic or inflammatory genes, showed lower expression levels. Sema3A activity was enhanced after P-PRP injection, whereas CD31 and NF200 expression levels were suppressed. CONCLUSIONS: P-PRP enhanced the performance of NPCs in IVDD by modifying the NF-κB signaling pathway and encouraging Sema3A expression, which may offer new therapy options for IVDD. THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE: The findings provide a new therapeutic target for the treatment of IVDD and show a novel light on the probable mechanism of PRP and the function of Sema3A in the progression of IVDD.

Sema3A Modified PDLSCs Exhibited Enhanced Osteogenic Capabilities and Stimulated Differentiation of Pre-Osteoblasts.

Genetically engineered stem cells, not only acting as vector delivering growth factors or cytokines but also exhibiting improved cell properties, are promising cells for periodontal tissue regeneration. Sema3A is a power secretory osteoprotective factor. In this study, we aimed to construct Sema3A modified periodontal ligament stem cells (PDLSCs) and evaluated their osteogenic capability and crosstalk with pre-osteoblasts MC3T3-E1. First, Sema3A modified PDLSCs was constructed using lentivirus infection system carrying Sema3A gene and the transduction efficiency was analyzed. The osteogenic differentiation and proliferation of Sema3A-PDLSCs was evaluated. Then, MC3T3-E1 was directly co-cultured with Sema3A-PDLSCs or cultured in condition medium of Sema3A-PDLSCs and the osteogenic ability of MC3T3-E1 was assessed. The results showed that Sema3A-PDLSCs expressed and secreted upregulated Sema3A protein, which confirmed successful construction of Sema3A modified PDLSCs. After osteogenic induction, Sema3A-PDLSCs expressed upregulated ALP, OCN, RUNX2, and SP7 mRNA, expressed higher ALP activity, and produced more mineralization nodes, compared with Vector-PDLSCs. Whereas, there was no obvious differences in proliferation between Sema3A-PDLSCs and Vector-PDLSCs. MC3T3-E1 expressed upregulated mRNA of ALP, OCN, RUNX2, and SP7 when directly co-cultured with Sema3A-PDLSCs than Vector-PDLSCs. MC3T3-E1 also expressed upregulated osteogenic markers, showed higher ALP activity, and produced more mineralization nodes when cultured using condition medium of Sema3A-PDLSCs instead of Vector-PDLSCs. In conclusion, our results indicated that Sema3A modified PDLSCs showed enhanced osteogenic capability, and also facilitated differentiation of pre-osteoblasts.

Semaphorin3A Exacerbates Cardiac Microvascular Rarefaction in Pressure Overload-Induced Heart Disease.

Microvascular endothelial cells (MiVECs) impair angiogenic potential, leading to microvascular rarefaction, which is a characteristic feature of chronic pressure overload-induced cardiac dysfunction. Semaphorin3A (Sema3A) is a secreted protein upregulated in MiVECs following angiotensin II (Ang II) activation and pressure overload stimuli. However, its role and mechanism in microvascular rarefaction remain elusive. The function and mechanism of action of Sema3A in pressure overload-induced microvascular rarefaction, is explored, through an Ang II-induced animal model of pressure overload. RNA sequencing, immunoblotting analysis, enzyme-linked immunosorbent assay, quantitative reverse transcription polymerase chain reaction (qRT-PCR), and immunofluorescence staining results indicate that Sema3A is predominantly expressed and significantly upregulated in MiVECs under pressure overload. Immunoelectron microscopy and nano-flow cytometry analyses indicate small extracellular vesicles (sEVs), with surface-attached Sema3A, to be a novel tool for efficient release and delivery of Sema3A from the MiVECs to extracellular microenvironment. To investigate pressure overload-mediated cardiac microvascular rarefaction and cardiac fibrosis in vivo, endothelial-specific Sema3A knockdown mice are established. Mechanistically, serum response factor (transcription factor) promotes the production of Sema3A; Sema3A-positive sEVs compete with vascular endothelial growth factor A to bind to neuropilin-1. Therefore, MiVECs lose their ability to respond to angiogenesis. In conclusion, Sema3A is a key pathogenic mediator that impairs the angiogenic potential of MiVECs, which leads to cardiac microvascular rarefaction in pressure overload-induced heart disease.

miR-196b-5p Regulates Osteoblast and Osteoclast Differentiation and Bone Homeostasis by Targeting SEMA3A.

miR-196b-5p plays a role in various malignancies. We have recently reported its function in regulating adipogenesis. However, it remains to be clarified whether and how miR-196b-5p affects bone cells and bone homeostasis. In this study, in vitro functional experiments showed an inhibitory effect of miR-196b-5p on osteoblast differentiation. Mechanistic explorations revealed that miR-196b-5p directly targeted semaphorin 3a (Sema3a) and inhibited Wnt/ß-catenin signaling. SEMA3A attenuated the impaired osteogenesis induced by miR-196b-5p. Osteoblast-specific miR-196b transgenic mice showed significant reduction of bone mass. Trabecular osteoblasts were reduced and bone formation was suppressed, whereas osteoclasts, marrow adipocytes, and serum levels of bone resorption markers were increased in the transgenic mice. The osteoblastic progenitor cells from the transgenic mice had decreased SEMA3A levels and exhibited retarded osteogenic differentiation, whereas those marrow osteoclastic progenitors exhibited enhanced osteoclastogenic differentiation. miR-196b-5p and SEMA3A oppositely regulated the expression of receptor activator of nuclear factor-κB ligand and osteoprotegerin. The calvarial osteoblastic cells expressing the transgene promoted osteoclastogenesis, whereas the osteoblasts overexpressing Sema3a inhibited it. Finally, in vivo transfection of miR-196b-5p inhibitor to the marrow reduced ovariectomy-induced bone loss in mice. Our study has identified that miR-196b-5p plays a key role in osteoblast and osteoclast differentiation and regulates bone homeostasis. Inhibition of miR-196b-5p may be beneficial for amelioration of osteoporosis. © 2023 American Society for Bone and Mineral Research (ASBMR).

Palmitoylation regulates neuropilin-2 localization and function in cortical neurons and conveys specificity to semaphorin signaling via palmitoyl acyltransferases.

Secreted semaphorin 3F (Sema3F) and semaphorin 3A (Sema3A) exhibit remarkably distinct effects on deep layer excitatory cortical pyramidal neurons; Sema3F mediates dendritic spine pruning, whereas Sema3A promotes the elaboration of basal dendrites. Sema3F and Sema3A signal through distinct holoreceptors that include neuropilin-2 (Nrp2)/plexinA3 (PlexA3) and neuropilin-1 (Nrp1)/PlexA4, respectively. We find that Nrp2 and Nrp1 are S-palmitoylated in cortical neurons and that palmitoylation of select Nrp2 cysteines is required for its proper subcellular localization, cell surface clustering, and also for Sema3F/Nrp2-dependent dendritic spine pruning in cortical neurons, both in vitro and in vivo. Moreover, we show that the palmitoyl acyltransferase ZDHHC15 is required for Nrp2 palmitoylation and Sema3F/Nrp2-dependent dendritic spine pruning, but it is dispensable for Nrp1 palmitoylation and Sema3A/Nrp1-dependent basal dendritic elaboration. Therefore, palmitoyl acyltransferase-substrate specificity is essential for establishing compartmentalized neuronal structure and functional responses to extrinsic guidance cues.

The role of Wnt, ARL4C, and Sema3A in developmental process and disease pathogenesis.

Various types of tumors, including malignant and benign ones, occur in the oral cavity. These arise from the mucosal epithelium, odontogenic epithelium, and salivary gland. To date, few major driver events in oral tumors have been identified. Accordingly, molecular targets in anti-tumor therapy for oral tumors are lacking. We focused on elucidating the function of aberrantly activated signal transduction related to oral tumor formation, especially in oral squamous cell carcinoma, ameloblastoma, and adenoid cystic carcinoma, which are raised as common oral tumors. Wnt/ß-catenin-dependent pathway is involved in the developmental process, organ homeostasis and disease pathogenesis through regulating various cellular functions by enhancing transcriptional activity. Recently, we identified ADP-ribosylation factor (ARF)-like 4c (ARL4C) and Semaphorin 3A (Sema3A), the expression of which is regulated by Wnt/ß-catenin-dependent pathway, and characterized their functions in the developmental process and tumor formation. This review highlights the recent advances in understanding the roles of Wnt/ß-catenin-dependent pathway, ARL4C and Sema3A, as determined by pathological and experimental studies.

CircSEC11A knockdown alleviates oxidative stress and apoptosis and promotes cell proliferation and angiogenesis by regulating miR-29a-3p/SEMA3A axis in OGD-induced human brain microvascular endothelial cells (HBMECs).

BACKGROUND: Circular RNA (circRNA) has been found to play an important role in the progression of many diseases, including ischemic stroke. However, the regulatory mechanism of circSEC11A in ischemic stroke progression need to further investigation. METHODS: Human brain microvascular endothelial cells (HBMECs) were stimulated by oxygen glucose deprivation (OGD). CircSEC11A, SEC11A mRNA and miR (microRNA)-29a-3p were quantified by quantitative real-time PCR (qRT-PCR). SEMA3A, BAX and BCL2 protein level was quantified by western blot. Oxidative stress, cell proliferation, angiogenesis and apoptosis abilities were gauged by oxidative stress assay kit, 5-Ethynyl-2'-Deoxyuridine (EdU) staining, tube formation assay and flow cytometry assays, respectively. Direct relationship between miR-29a-3p and circSEC11A or SEMA3A was validated by dual-luciferase reporter assay, RIP assay and RNA pull-down assay. RESULTS: CircSEC11A was upregulated in OGD-induced HBMECs. OGD promoted the oxidative stress and apoptosis and inhibited cell proliferation and angiogenesis, while circSEC11A knockdown relieved the effects. CircSEC11A functioned as the sponge for miR-29a-3p, and miR-29a-3p inhibitor reversed the effects of si-circSEC11A on OGD-induced HBMECs oxidative injuries. Moreover, SEMA3A served as the target gene of miR-29a-3p. MiR-29a-3p inhibition ameliorated OGD-induced HBMECs oxidative injuries, while SEMA3A overexpression rescued the impacts of miR-29a-3p mimic. CONCLUSION: CircSEC11A promoted the malignant progression in OGD-induced HBMECs through the mediation of miR-29a-3p/SEMA3A axis. This study has provided the new insight into the underlying application of circSEC11A in cell model of ischemic stroke.

Sema3A alleviates viral myocarditis by modulating SIRT1 to regulate cardiomyocyte mitophagy.

Viral myocarditis (VMC) is a common myocardial inflammatory disease characterized by inflammatory cell infiltration and cardiomyocyte necrosis. Sema3A was reported to reduce cardiac inflammation and improve cardiac function after myocardial infarction, but its role in VMC remains to be explored. Here, a VMC mouse model was established by infection with CVB3, and Sema3A was overexpressed in vivo by intraventricular injection of an adenovirus-mediated Sema3A expression vector (Ad-Sema3A). We found that Sema3A overexpression attenuated CVB3-induced cardiac dysfunction and tissue inflammation. And Sema3A also reduced macrophage accumulation and NLRP3 inflammasome activation in the myocardium of VMC mice. In vitro, LPS was used to stimulate primary splenic macrophages to mimic the macrophage activation state in vivo. Activated macrophages were co-cultured with primary mouse cardiomyocytes to evaluate macrophage infiltration-induced cardiomyocyte damage. Ectopic expression of Sema3A in cardiomyocytes effectively protected cardiomyocytes from activated macrophage-induced inflammation, apoptosis, and ROS accumulation. Mechanistically, cardiomyocyte-expressed Sema3A mitigated macrophage infiltration-caused cardiomyocyte dysfunction by promoting cardiomyocyte mitophagy and hindering NLRP3 inflammasome activation. Furthermore, NAM (a SIRT1 inhibitor) reversed the protective effect of Sema3A against activated macrophage-induced cardiomyocyte dysfunction by suppressing cardiomyocyte mitophagy. In conclusion, Sema3A promoted cardiomyocyte mitophagy and suppressed inflammasome activation by regulating SIRT1, thereby attenuating macrophage infiltration-induced cardiomyocyte injury in VMC.

IGF2BP1 regulates the cargo of extracellular vesicles and promotes neuroblastoma metastasis.

Neuroblastoma is a highly metastatic cancer, and thus is one of the leading causes of cancer-related mortalities in pediatric patients. More than 50% of NB cases exhibit 17q21-ter partial chromosomal gain, which is independently associated with poor survival, suggesting the clinical importance of genes at this locus in NB. IGF2BP1 is one such proto-oncogene located at 17q locus, and was found to be upregulated in patients with metastatic NBs. Here, utilizing multiple immunocompetent mouse models, along with our newly developed highly metastatic NB cell line, we demonstrate the role of IGF2BP1 in promoting NB metastasis. Importantly, we show the significance of small extracellular vesicles (EVs) in NB progression, and determine the pro-metastatic function of IGF2BP1 by regulating the NB-EV-protein cargo. Through unbiased proteomic analysis of EVs, we discovered two novel targets (SEMA3A and SHMT2) of IGF2BP1, and reveal the mechanism of IGF2BP1 in NB metastasis. We demonstrate that IGF2BP1 directly binds and governs the expression of SEMA3A/SHMT2 in NB cells, thereby modulating their protein levels in NB-EVs. IGF2BP1-affected levels of SEMA3A and SHMT2 in the EVs, regulate the formation of pro-metastatic microenvironment at potential metastatic organs. Finally, higher levels of SEMA3A/SHMT2 proteins in the EVs derived from NB-PDX models indicate the clinical significance of the two proteins and IGF2BP1-SEMA3A/SHMT2 axis in NB metastasis.