Search Results (57)

Proliferative vitreoretinopathy (PVR) remains a leading cause of surgical failure after rhegmatogenous retinal detachment (RRD) repair. Although PVR involves multiple cell types and signaling pathways, epithelial–mesenchymal transition (EMT) and related plasticity of retinal pigment epithelial (RPE) cells are major contributors to fibrocellular membrane formation and contraction. Semaphorin 3A (SEMA3A) has therefore attracted interest as a potential negative regulator of these pathogenic RPE responses. Recombinant SEMA3A inhibits RPE migration and proliferation and attenuates experimental PVR when administered at model induction. Yet this benefit does not establish that endogenous SEMA3A transcript levels are reduced. Published Source Data from a mouse model of traumatic PVR show significantly increased endogenous Sema3a transcript levels in RPE preparations compared with controls. The question is therefore why PVR progresses despite increased endogenous Sema3a transcript levels in this model. Possible explanations include microRNA-mediated translational repression, altered protein processing or secretion, reduced extracellular availability, and impaired NRP1/plexin signaling. MicroRNAs (miRNAs) are particularly relevant because they can reduce protein output without a parallel decline in mRNA and can regulate multiple features of RPE EMT. This narrative review examines current evidence for SEMA3A in PVR, summarizes miRNA regulation of RPE EMT and related PVR phenotypes, and evaluates direct and indirect evidence for miRNA–SEMA3A interactions. We also compare the miRNA hypothesis with alternative explanations for inadequate endogenous SEMA3A activity and consider its implications for ocular biomarkers and target-site-selective RNA therapy. Current evidence makes miRNA-mediated regulation of SEMA3A a plausible and testable mechanism, although a causal role has yet to be demonstrated in RPE cells or PVR. Full article

Plexin-B1, Plexin-B2, and Plexin-B3 are members of the Plexin-B receptor family, which engage distinct class IV semaphorins as major ligands: Plexin-B1 binds SEMA4D, Plexin-B2 interacts with SEMA4C and SEMA4B, and Plexin-B3 has been reported to bind HSPA5, while all three may participate in non-redundant ligand–receptor networks. Researchers have found receptors associated with neurological and malignant, immune-mediated, and cardiovascular diseases. However, this study strives to provide a comprehensive, cross-disciplinary synthesis of the context-specific functions of Plexin-B family members and to critically evaluate their emerging therapeutic potential across multiple disease domains. In a tumor- and context-dependent manner, Plexin-B1 and Plexin-B2 promote metastasis in glioblastoma, colorectal cancer, and triple-negative breast cancer (TNBC) through RhoA/Rac1-dependent signaling, while Plexin-B3 exhibits dual roles, acting as a tumor suppressor in TNBC under hypoxic conditions yet promoting motility in pancreatic cancer. Plexin-B regulates neuroinflammation in Alzheimer’s disease and T-cell regulation in asthma and other cardiovascular diseases via signals. This review positions the Plexin-B family as a promising yet functionally complex target for future precision medicine. Full article

Neuropathic pain is a debilitating condition arising from lesions or diseases affecting the somatosensory nervous system. Despite significant advances in understanding its pathophysiology, the molecular mechanisms underlying the development and persistence of neuropathic pain remain incompletely understood. Semaphorins, a highly conserved family of axon guidance molecules, have emerged as key regulators of neuronal development, synaptic plasticity, immune responses, and neurovascular interactions. Beyond their roles during nervous system development, accumulating evidence indicates that semaphorins and their receptors, including plexins and neuropilins, actively participate in the pathological processes associated with peripheral and central sensitization following nerve injury. Altered semaphorin signaling has been implicated in neuroinflammation, aberrant axonal regeneration, glial cell activation, and dysregulated nociceptive transmission, thus contributing to the initiation and maintenance of neuropathic pain. Furthermore, several semaphorin family members show different effects, highlighting their multifaceted functions within the injured nervous system. This review summarizes the current understanding of semaphorin-mediated mechanisms involved in neuropathic pain and explores their interactions with inflammatory and neuroimmune pathways. A deeper understanding of semaphorin signaling might provide novel insights into the pathogenesis of neuropathic pain and facilitate the development of more effective treatment strategies. Full article

Semaphorins are a large family of proteins originally identified for their roles in axon guidance during neural development. Recent findings have established the importance of semaphorins members in modulating diverse immune responses of T cells in vitro and in vivo. Class 3 semaphorins, typified by Sema3A, signal through Neuropilin-1 and Plexin-A receptors in an activation-dependent manner, suppressing effector proliferation while promoting regulatory T cell stability and shaping cytokine profiles in autoimmunity and cancer. Sema3E and Sema3F similarly fine-tune host defense and inflammation by directing Th1/Th17 responses or restraining aberrant chemotaxis. Class 4 members, such as Sema4A and Sema4D, engage Plexin-B1, Plexin-D1, and CD72 to deliver both “forward” co-stimulatory and “reverse” signals: they amplify CD4⁺ and CD8⁺ effector functions, support T helper-B cell crosstalk, and influence tumor immunity via receptor shedding and bidirectional signaling. Finally, although less well defined, class 7 Sema7A operates indirectly—through APCs and Tregs—to regulate inflammatory recall responses and Th1/Th17 driven pathology. Together, these semaphorin-mediated pathways underscore a complex, context-dependent network that balances protective immunity against immunopathology, offering novel therapeutic targets in autoimmunity, infection, and cancer. Full article

Successful organ regeneration depends on coordinated cell-to-cell communication mediated by ligand–receptor interactions that regulate proliferation, differentiation, and axonal guidance. Sea cucumbers, particularly Holothuria glaberrima, exhibit remarkable regenerative capacity following evisceration, regenerating their complete intestinal system within weeks. To identify molecular signals orchestrating these events, we characterized five ligand–receptor groups of axonal guidance molecules (Netrin/UNC5-DSCAM, Ephrin/Eph receptors, Semaphorin/Plexin, RGMα/Neogenin, and SLIT/ROBO) using transcriptomic databases from regenerating intestines and the radial nerve cord. Comparative analyses confirmed these as highly conserved orthologs, retaining characteristic structural domains essential for guidance signaling. Multiple alternatively spliced isoforms were detected, with tissue-specific variants suggesting functional diversification. Differential gene expression analysis across intestinal regeneration stages (12 h to 21 days post-evisceration) revealed distinct temporal patterns: Netrin-1 showed significant upregulation at 7–14 days post-evisceration, coinciding with nerve fiber invasion into the intestinal anlage, while the Ephrin, Semaphorin, and SLIT–ROBO pathways exhibited late-stage expression associated with luminal tissue formation. Single-cell RNA sequencing from 9-dpe regenerating intestines localized Netrin to coelomic epithelial cells and UNC5B to differentiating epithelial cells, with CellChat analysis predicting strong epithelial-to-epithelial signaling. These findings strongly suggest that axonal guidance molecules play dual roles during intestinal regeneration: directing neural innervation in early-to-mid stages and orchestrating tissue boundary formation at later stages. Full article

Intracerebral hemorrhage (ICH) is the deadliest subtype of stroke, and its primary harm to the human body arises from the formation of brain hematomas. Promoting microglial-mediated endogenous hematoma clearance has become a key focus in current ICH treatment strategies. Semaphorin 3s (Sema3s) are molecular signals involved in the regulation of the central nervous system, angiogenesis, and microenvironment homeostasis, and they are closely associated with various central nervous system diseases. Hematoma clearance and inflammation regulation are crucial to the role of microglia, yet the mechanisms by which Sema3s regulate microglia after ICH remain unclear. Here, using high-throughput RNA sequencing of a mouse ICH model, we identified that neuron-derived Sema3B is downregulated after ICH. Further mechanistic studies revealed that Sema3B can bind to PlexinA1 on microglia, activating NRF2 to promote the expression of the phagocytic receptor TREM2 and the key hematoma clearance molecule HO-1. Furthermore, Sema3B enhances the interaction between PlexinA1 and TREM2, cooperatively boosting microglial phagocytosis of the hematoma after ICH. Furthermore, Sema3B regulates the M2 polarization of microglia, exerting an anti-inflammatory effect. Our findings suggest that manipulating microglial phagocytosis of hematoma and inflammation suppression via regulation of Sema3B may be a potential strategy for treating patients with ICH. Full article

The MET oncogene, encoding the hepatocyte growth factor (HGF) receptor, plays a key role in tumorigenesis, invasion, and resistance to therapy, yet its full biological functions and activation mechanisms remain incompletely understood. A feature of MET is its extensive interaction network, encompassing the following: (i) receptor tyrosine kinases (RTKs); (ii) co-receptors (e.g., CDCP1, Neuropilin1); (iii) adhesion molecules (e.g., integrins, tetraspanins); (iv) proteases (e.g., ADAM10); and (v) other receptors (e.g., CD44, plexins, GPCRs, and NMDAR). These interactions dynamically modulate MET’s activation, signaling, intracellular trafficking, and degradation, enhancing its functional versatility and oncogenic potential. This review offers current knowledge on MET’s partnerships, focusing on their functional impact on signaling output, therapeutic resistance, and cellular behavior. Finally, we evaluate emerging combination therapies targeting MET and its interactors, highlighting their potential to overcome resistance and improve clinical outcomes. By exploring the complex interplay within the MET network of interacting cell surface proteins, this review provides insights into advancing anti-cancer strategies and understanding the broader implications of RTK crosstalk in oncology. Full article

Semaphorins are an immunoregulatory protein family. Plexins bind semaphorins (SEMAs) and can form receptor complexes that give them chemotactic capacity. The role and expression profile of semaphorins and plexins in inflammatory bowel disease (IBD) is currently unknown. Aim: Characterize the semaphorins and plexins gene and protein expression in intestinal tissue from IBD patients and correlate them with the clinical phenotype. Material and Methods: This comparative and cross-sectional study enrolled 54 diagnosed IBD patients and 20 controls. Gene and protein expression of semaphorins and plexins were determined by RT-PCR and IHQ for the co-localization with neutrophils (myeloperoxidase, MPO) or CD123 plasmacytoid dendritic cells in intestinal tissue from IBD patients. Results: Colonic mucosa from active and remission ulcerative colitis (UC) had a significantly lower SEMA4D and PLXNA1, but higher PLXNB1 gene expression than the control group. The only significant difference between active UC and remission was observed in the higher gene expression of SEMA6D in remission. It was associated with histological remission (p = 0.01, OR = 15, 95% CI: 1.39–16.1). The low expression of PLXNA1 was associated with mild intermittent activity with two relapses per year (p = 0.003, OR = 0.05, CI = 0.006–0.51). Higher SEMA4D+ positive cells were detected in the submucosa, while PLXNC1+/MPO+ in the mucosal and submucosa of active UC patients compared with controls. Conclusions: The increased expression of the semaphorin and plexin family in IBD patients suggests their immunoregulatory function and is associated with remission and clinical phenotype in patients with UC. Full article

The present study aims to evaluate the effect of a dietary supplementation with 10% grape pomace (GP) on the whole blood transcriptome of lactating ewes. By applying a log₂FC higher than 0.5 or lower than −0.5 and a false discovery rate (FDR) <0.05, the down-regulation of genes coding for plexin C1, ethanolamine kinase 1, tax1-binding protein 1, transmembrane 9 superfamily member 2, and Beclin-1 was observed in animals that received the dietary supplementation. This aspect was also accompanied by a reduction in the blood activity of matrix metalloproteinase 9 (MMP-9; p < 0.05), a gelatinase commonly involved in both acute and chronic pathological events. The ELISA test on other factors involved in inflammatory processes, interleukin 1 (IL-1) and tumor necrosis factor α (TNF-α), as well as in the antioxidant response, glutathione peroxidase (GPx), and catalase (CAT), did not reveal any significant changes (p > 0.05). Overall, the introduction of GP in the diet of ewes gave indications of greater efficacy in preserving animal welfare, with interesting cues regarding the valorization of a by-product with a high biological value. Full article

Glaesserella parasuis (G. parasuis) causes serious inflammation and meningitis in piglets. Quercetin has anti-inflammatory and anti-bacterial activities; however, whether quercetin can alleviate brain inflammation and provide protective effects during G. parasuis infection has not been studied. Here, we established a mouse model of G. parasuis infection in vivo and in vitro to investigate transcriptome changes in the mouse cerebrum and determine the protective effects of quercetin on brain inflammation and blood–brain barrier (BBB) integrity during G. parasuis infection. The results showed that G. parasuis induced brain inflammation, destroyed BBB integrity, and suppressed PI3K/Akt/Erk signaling-pathway activation in mice. Quercetin decreased the expression of inflammatory cytokines (Il-18, Il-6, Il-8, and Tnf-α) and BBB-permeability marker genes (Mmp9, Vegf, Ang-2, and Et-1), increased the expression of angiogenetic genes (Sema4D and PlexinB1), reduced G. parasuis-induced tight junction disruption, and reactivated G. parasuis-induced suppression of the PI3K/Akt/Erk signaling pathway in vitro. Thus, we concluded that quercetin may protect BBB integrity via the PI3K/Akt/Erk signaling pathway during G. parasuis infection. This was the first attempt to explore the protective effects of quercetin on brain inflammation and BBB integrity in a G. parasuis-infected mouse model. Our findings indicated that quercetin is a promising natural agent for the prevention and treatment of G. parasuis infection. Full article

Caveolin-1 (Cav1) is a major plasma membrane protein that plays important functions in cellular metabolism, proliferation, and senescence. Mice lacking Cav1 show abnormal gene expression in the fetal brain. Though evidence for placental influence on brain development is emerging, whether the ablation of Cav1 affects the regulation of the brain–placental axis remains unexamined. The current study tests the hypothesis that gene expression changes in specific cells of the placenta and the fetal brain are linked to the deregulation of the brain–placental axis in Cav1-null mice. By performing single-nuclei RNA sequencing (snRNA-seq) analyses, we show that the abundance of the extravillious trophoblast (EVT) and stromal cells, but not the cytotrophoblast (CTB) or syncytiotrophoblast (STB), are significantly impacted due to Cav1 ablation in mice. Interestingly, specific genes related to brain development and neurogenesis were significantly differentially expressed in trophoblast cells due to Cav1 deletion. Comparison of single-cell gene expression between the placenta and the fetal brain further showed that specific genes such as plexin A1 (Plxna1), phosphatase and actin regulator 1 (Phactr1) and amyloid precursor-like protein 2 (Aplp2) were differentially expressed between the EVT and STB cells of the placenta, and also, between the radial glia and ependymal cells of the fetal brain. Bulk RNA-seq analysis of the whole placenta and the fetal brain further identified genes differentially expressed in a similar manner between the placenta and the fetal brain due to the absence of Cav1. The deconvolution of reference cell types from the bulk RNA-seq data further showed that the loss of Cav1 impacted the abundance of EVT cells relative to the stromal cells in the placenta, and that of the glia cells relative to the neuronal cells in the fetal brain. Together, the results of this study suggest that the ablation of Cav1 causes deregulated gene expression in specific cell types of the placenta and the fetal brain in mice. Full article

Autism spectrum disorder (ASD) is a neurodevelopmental disorder that includes autism, Asperger’s syndrome, and pervasive developmental disorder. ASD is characterized by poor interpersonal relationships and strong attachment. The correlations between activated or inactivated gene products, which occur as a result of genetic mutations affecting neurons in ASD patients, and ASD symptoms are now of critical concern. Here, for the first time, we describe the process in which that the respective ASD-associated mutations (Arg676-to-Cys [R676C] and Ser951-to-Cys [S951C]) of semaphorin-5A (Sema5A) localize Sema5A proteins themselves around the plasma membrane in the N1E-115 cell line, a model line that can achieve neuronal morphological differentiation. The expression of each mutated construct resulted in the promotion of excessive elongation of neurite-like processes with increased differentiation protein markers; R676C was more effective than S951C. The differentiated phenotypes were very partially neutralized by an antibody, against Plexin-B3 as the specific Sema5A receptor, suggesting that the effects of Sema5A act in an autocrine manner. R676C greatly increased the activation of c-Jun N-terminal kinase (JNK), one of the signaling molecules underlying process elongation. In contrast, the blocking of JNK signaling, by a chemical JNK inhibitor or an inhibitory construct of the interaction of RhoG with Elmo1 as JNK upstream signaling molecules, recovered the excessive process elongation. These results suggest that ASD-associated mutations of Sema5A, acting through the JNK signaling cascade, lead to excessive differentiated phenotypes, and the inhibition of JNK signaling recovers them, revealing possible therapeutic targets for recovering the potential molecular and cellular phenotypes underlying certain ASD symptoms. Full article

According to recent evidence, some groups of semaphorins (SEMAs) have been associated with cancer progression. These proteins are able to modulate the cellular signaling of particular receptor tyrosine kinases (RTKs) via the stimulation of SEMA-specific coreceptors, namely plexins (plexin-A, -B, -C, -D) and neuropilins (Np1, Np2), which share common domains with RTKs, leading to the coactivation of the latter receptors. MET, ERBB2, VEGFR2, PFGFR, and EGFR, among others, represent acknowledged targets of semaphorins that are often associated with tumor progression or poor prognosis. In particular, higher expression of SEMA6 family proteins in cancer cells and stromal cells of the cancer niche is often associated with enhanced tumor angiogenesis, metastasis, and resistance to anticancer therapy. Notably, high SEMA6 expression in malignant tumor cells such as melanoma, pleural mesothelioma, gastric cancer, lung adenocarcinoma, and glioblastoma may serve as a prognostic biomarker of tumor progression. To date, very few studies have focused on the mechanisms of transmembrane SEMA6-driven tumor progression and its underlying interplay with RTKs within the tumor microenvironment. This review presents the growing evidence in the literature on the complex and shaping role of SEMA6 family proteins in cancer responsiveness to environmental stimuli. Full article

In recent years, olfactory dysfunction has attracted increasingly more attention as a hallmark symptom of neurodegenerative diseases (ND). Deeply understanding the molecular basis underlying the development of the olfactory bulb (OB) will provide important insights for ND studies and treatments. Now, with a genetic knockout mouse model, we show that TRIM67, a new member of the tripartite motif (TRIM) protein family, plays an important role in regulating the proliferation and development of mitral cells in the OB. TRIM67 is abundantly expressed in the mitral cell layer of the OB. The genetic deletion of TRIM67 in mice leads to excessive proliferation of mitral cells in the OB and defects in its synaptic development, resulting in reduced olfactory function in mice. Finally, we show that TRIM67 may achieve its effect on mitral cells by regulating the Semaphorin 7A/Plexin C1 (Sema7A/PlxnC1) signaling pathway. Full article

Breast cancer is the most common cancer worldwide and a leading cause of cancer-related deaths in women. The clinical management of breast cancer is further complicated by the heterogeneous nature of the disease, which results in varying prognoses and treatment responses in patients. The semaphorins are a family of proteins with varied roles in development and homoeostasis. They are also expressed in a wide range of human cancers and are implicated as regulators of tumour growth, angiogenesis, metastasis and immune evasion. More recently, semaphorins have been implicated in drug resistance across a range of malignancies. In breast cancer, semaphorins are associated with resistance to endocrine therapy as well as breast cancer chemotherapeutic agents such as taxanes and anthracyclines. This review will focus on the semaphorins involved in breast cancer progression and their association with drug resistance. Full article