BACKGROUND: Semaphorin 3A (Sema3A) is a member of neural guidance factor family well-known for inducing the collapse of nerve cell growth cone and regulating nerve redistribution. It also has been characterized as an immunoregulatory and tumor promoting factor. Our previous study showed that Sema3A was involved in the regulation of sympathetic innervation and neuropathic pain of endometriosis. Nevertheless, the role of Sema3A in the development of endometriosis and its potential upstreaming factor are still not clear.
METHODS: Histology experiments were carried to detect the expression of Sema3A, hypoxia -inducible factor 1α (HIF-1α) and the distribution of macrophages. Cell experiments were used to explore the effect of Sema3A on the proliferation and migration of endometrial stromal cells (ESCs) and to confirm the regulatory action of HIF-1α on Sema3A. In vivo experiments were carried out to explore the role of Sema3A on the development of endometriosis.
RESULTS: Sema3A was highly expressed in endometriotic lesions and could enhanced the proliferation and migration abilities of ESCs. Aberrant macrophage distribution was found in endometriotic lesions. Sema3A also promoted the differentiation of monocytes into anti-inflammatory macrophages, so indirectly mediating the proliferation and migration of ESCs. Hypoxic microenvironment induced Sema3A mRNA and protein expression in ESCs via HIF-1α. Administration of Sema3A promoted the development of endometriosis in a mouse model.
CONCLUSIONS: Sema3A, which is regulated by HIF-1α, is a promoting factor for the development of endometriosis. Targeting Sema3A may be a potential treatment strategy to control endometriotic lesions.

Semaphorin 3A (SEMA3A), a nerve-repellent factor produced by keratinocytes, has an inhibitory effect on nerve extension to the epidermis. Epidermal innervation is involved in pruritus in inflammatory skin diseases such as atopic dermatitis (AD) and dry skin. We previously reported that tapinarof, a stilbene molecule, upregulates SEMA3A in human keratinocytes. We also showed that this mechanism is mediated via the aryl hydrocarbon receptor (AHR), a ligand-activated transcription factor, and the nuclear factor erythroid 2-related factor 2 (NRF2) axis. Since some stilbenes activate AHR and NRF2, we attempted to identify other stilbenes that upregulate SEMA3A. We analyzed normal human epidermal keratinocytes (NHEKs) treated with 11 types of stilbenes and examined SEMA3A expression. We found that resveratrol and pinostilbene, antioxidant polyphenols, upregulated SEMA3A and increased nuclear AHR and NRF2 expression. In addition, AHR knockdown by small interfering RNA (siRNA) transfection abolished the NRF2 nuclear expression. Furthermore, AHR and NRF2 knockdown by siRNA transfection abrogated resveratrol- and pinostilbene-induced SEMA3A upregulation. Finally, we confirmed that resveratrol and pinostilbene increased SEMA3A promoter activity through NRF2 binding using ChIP-qPCR analysis. These results suggest that resveratrol and pinostilbene upregulate SEMA3A via the AHR-NRF2 axis in human keratinocytes.

Axonal outgrowth after stroke plays an important role in tissue repair and is critical for functional recovery. In the peri-infarct area of a rat middle cerebral artery occlusion model, we found that the axons and dendrites that had fallen off in the acute phase of stroke (7 days) were regenerated in the chronic phase of stroke (56 days). In vitro, we showed that phosphatase tensin homolog deleted on chromosome 10/Akt/Glycogen synthase kinase 3β signaling is implicated in postischemic axonal regeneration. In a rat model of chronic cerebral hypoperfusion, oral administration of L-carnitine induced axonal and oligodendrocyte regeneration in the cerebral white matter, resulting in myelin thickening, and it improved cognitive impairment in rats with chronic cerebral ischemia. Recently, it has been shown that exosomes enhanced functional recovery after stroke. Exosome treatment has less tumorigenicity, does not occlude the microvascular system, has low immunogenicity, and does not require a host immune response compared to conventional cell therapy. Several studies demonstrated specific microRNA in exosomes, which regulated signaling pathways related to neurogenesis after stroke. Collectively, there are various mechanisms of axonal regeneration and functional recovery after stroke, and it is expected that new therapeutic agents for stroke with the aim of axonal regeneration will be developed and used in real-world clinical practice in the future.

The initiation and progression of atherosclerotic plaque caused by abnormal lipid metabolism is one of the main causes of atherosclerosis (AS). Lipid droplet accumulation has become a novel research pointcut for AS treatment in recent years. In AS patients, miR-135b level was up-regulated relative to the normal cases, which showed negative correlations with the levels of Semaphorin 3A (SEMA3A) and circZNF609, separately. The U937-derived macrophages were cultured with ox-LDL to establish AS models in vitro. After that, the lipid accumulation, inflammation, mitochondrial dysfunction and cell death were evaluated by ORO, ELISA, RT-qPCR, western blot, JC-1 and FCM assays respectively. Transfection of the circZNF609 expression vector notably declined lipid accumulation, attenuated inflammation, reduced mitochondrial dysfunction and inhibited cell death in ox-LDL-stimulated cells. The direct binding of miR-135b to circZNF609 in vitro was confirmed using RIP assay, and SEMA3A expression was up-regulated by circZNF609 overexpression. After manipulating the endogenous expressions of circZNF609, miR-135b and SEMA3A, the above damages in ox-LDL-stimulated cells were rescued by inhibition of miR-135b expression and overexpression of circZNF609 or SEMA3A. Besides, the AS mice model was built to demonstrate the excessive lipid accumulation, increasing inflammation and cell death in AS pathogenesis according to the results of HE staining, ELISA and IHC assays, while these damages were reversed after overexpression of circZNF609 or SEMA3A. In AS models, overexpressed circZNF609 prevents the AS progression through depleting miR-135b expression and subsequent up-regulation of SEMA3A expression to overwhelm lipid accumulation, mitochondrial dysfunction and cell death.

BACKGROUND: Osteolytic bone metastasis is a common complication of Non-Small Cell Lung Cancer (NSCLC), resulting in bone pain, hypercalcemia, and fractures that severely reduce the quality of life and survival time of patients. Semaphorins 3A (Sema3A) is one of the isoforms of the Semaphorins family, which is important in a variety of physiological and pathological processes, such as angiogenesis, immune regulation, and tumorigenesis. However, the role of Sema3A in the development of osteolytic bone metastasis in NSCLC is unknown.
METHODS: In this study, we established in vitro models simulating NSCLC cells in regulating the differentiation and maturation of osteoblast and osteoclast precursors and observed the differentiation of osteoblasts and osteoclasts.
RESULTS: The results demonstrated that the expression of Sema3A inhibited the proliferation, migration, and invasion of NSCLC cells, as well as promoted the differentiation of osteoblasts and inhibited the differentiation of osteoclasts, suggesting that Sema3A can inhibit the occurrence and development of osteolytic bone metastasis of NSCLC.
CONCLUSIONS: This study provides a new idea for the clinical treatment of osteolytic bone metastasis in NSCLC.

Sensory nerves play a crucial role in maintaining bone homeostasis by releasing Semaphorin 3A (Sema3A). However, the specific mechanism of Sema3A in regulation of bone marrow mesenchymal stem cells (BMMSCs) during bone remodelling remains unclear. The tibial denervation model was used and the denervated tibia exhibited significantly lower mass as compared to sham operated bones. In vitro, BMMSCs cocultured with dorsal root ganglion cells (DRGs) or stimulated by Sema3A could promote osteogenic differentiation through the Wnt/β-catenin/Nrp1 positive feedback loop, and the enhancement of osteogenic activity could be inhibited by SM345431 (Sema3A-specific inhibitor). In addition, Sema3A-stimulated BMMSCs or intravenous injection of Sema3A could promote new bone formation in vivo. To sum up, the coregulation of bone remodelling is due to the ageing of BMMSCs and increased osteoclast activity. Furthermore, the sensory neurotransmitter Sema3A promotes osteogenic differentiation of BMMSCs via Wnt/β-catenin/Nrp1 positive feedback loop, thus promoting osteogenesis in vivo and in vitro.

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-β)-induced EndMT, we used human atria, isolated human atrial endocardial endothelial cells (AEECs), and used transgenic mice expressing TGF-β specifically in cardiac tissues (TGF-β 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-β 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-β 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.

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.
戈勒姆综合征（Gorham-Stout disease, GSD）是一种罕见的散发性慢性骨科疾病，以进行性骨溶解、吸收和消失为特征，伴骨髓腔淋巴管浸润。虽然GSD的溶骨机制已被广泛研究，但其骨中淋巴管增生的原因却很少被触及。本研究通过RNA测序，比较破骨细胞（OCs）和破骨细胞前体（OCPs）的RNA表达谱，发现了具有骨保护作用的因子信号素3A（Sema3A）在OCs中的表达显著降低了。并且与OCPs相比，OCs促进了淋巴管内皮细胞（LECs）的生长、迁移和体外淋巴管管状形成。同时体外研究发现，重组Sema3A能抑制LECs的生长、迁移和体外淋巴管管状形成，证实了Sema3A对LECs的抑制作用。采用LECs诱导的GSD小鼠模型，通过在胫骨内注射表达Sema3A的慢病毒，我们进一步检测Sema3A在体内的作用。结果表明，在胫骨中过表达Sema3A可抑制LECs的扩张，减少骨丢失。而在胫骨中注射表达Sema3A shRNA的慢病毒以敲低Sema3A的表达可引发小鼠胫骨GSD样表型。组织学染色分析表明，与对照组相比，Sema3A慢病毒治疗后OCs减少，骨钙素增加。基于以上结果，我们认为OCs中Sema3A的减少是GSD的发病机制之一，表达Sema3A代表了一种治疗GSD的新方案。.

Semaphorin 3A (Sema3A) is a neuroinformatic protein molecule with widespread expression across various tissues and organs. Recent investigations have unveiled its pivotal role in the skeletal system, primarily through its binding interactions with two co-receptors, neuropilin-1 (Nrp-1) and members of the plexin family. Prior research has confirmed the expression of Sema3A and its receptors in both osteocytes and chondrocytes. Beyond its expression patterns, Sema3A plays a multifaceted role in regulating bone and cartilage metabolism via employing diverse signaling pathways. Additionally, it engages in collaborative interactions with the immune and nervous systems, contributing to the pathophysiological processes underlying a spectrum of bone and joint diseases. In this paper, we undertake a comprehensive review of recent research developments in this field. Our objective is to deepen the understanding of Sema3A within the context of skeletal physiology and pathology. Furthermore, we aim to furnish a valuable reference for potential therapeutic interventions in the realm of bone and joint diseases.

Neonatal hypoxic-ischemic encephalopathy (HIE) is an abnormal neurological condition caused by hypoxic-ischemic damage during the perinatal period. Human placenta derived mesenchymal stem cells (hPMSCs) have been shown to have protective and reparative effects in various neurological diseases; however, the research on HIE is insufficient. This study aimed to establish a rat model of HIE and transplant hPMSCs through the lateral ventricle after hypoxic-ishcemic (HI) brain damage to observe its protective effects and mechanisms, with a focus on brain apoptosis compared among groups. Differentially expressed apoptosis-related proteins were screened using a rat cytokine array and subsequent verification. Neuropilin-1 (NRP-1) and Semaphorin 3A (Sema 3A) were selected for further investigation. Western blotting was used to quantify the expression of Sema 3A and the proteins related to PI3K/Akt/mTOR signaling pathway. Exogenous Sema 3A was added to evaluate the effects of Sema 3A/NRP-1 on hPMSCs following HI injury. hPMSCs transplantation ameliorated HI-induced pathological changes, reduced apoptosis, and improved long-term neurological prognosis. Furthermore, Sema 3A/NRP-1 was a key regulator in reducing HI-induced apoptosis after hPMSCs transplantation. hPMSCs inhibited the expression of Sema 3A/NRP-1 and activated the PI3K/Akt/mTOR signaling pathway. Additionally, exogenous Sema 3A abolished the protective effects of hPMSCs against HI. In conclusion, hPMSCs transplantation reduced apoptosis and improved long-term neurological prognosis after HI by downregulating Sema 3A/NRP-1 expression and activating the PI3K/Akt/mTOR signaling pathway.