Gene expression of semaphorin-3A, semaphorin-7A, neuropilin-1, plexin-C1, and β1 integrin in treated-multiple sclerosis patients

Semaphorin 7a aggravates TGF-β1-induced airway EMT through the FAK/ERK1/2 signaling pathway in asthma

Background

TGF-β1 can induce epithelial-mesenchymal transition (EMT) in primary airway epithelial cells (AECs). Semaphorin7A (Sema7a) plays a crucial role in regulating immune responses and initiating and maintaining transforming growth factor β1 TGF-β1-induced fibrosis.

Objective

To determine the expression of Sema7a, in serum isolated from asthmatics and non-asthmatics, the role of Sema7a in TGF-β1 induced proliferation, migration and airway EMT in human bronchial epithelial cells (HBECs) in vitro.

Methods

The concentrations of Sema7a in serum of asthmatic patients was detected by enzyme-linked immunosorbent assay (ELISA). The expressions of Sema7a and integrin-β1 were examined using conventional western blotting and real-time quantitative PCR (RT-PCR). Interaction between the Sema7a and Integrin-β1 was detected using the Integrin-β1 blocking antibody (GLPG0187). The changes in EMT indicators were performed by western blotting and immunofluorescence, as well as the expression levels of phosphorylated Focal-adhesion kinase (FAK) and Extracellular-signal-regulated kinase1/2 (ERK1/2) were analyzed by western blot and their mRNA expression was determined by RT-PCR.

Results

We described the first differentially expressed protein of sema7a, in patients with diagnosed bronchial asthma were significantly higher than those of healthy persons (P<0.05). Western blotting and RT-PCR showed that Sema7a and Integrin-β1 expression were significantly increased in lung tissue from the ovalbumin (OVA)-induced asthma model. GLPG0187 inhibited TGF-β1-mediated HBECs EMT, proliferation and migration, which was associated with Focal-adhesion kinase (FAK) and Extracellular-signal-regulated kinase1/2 (ERK1/2) phosphorylation.

Conclusion

Sema7a may play an important role in asthma airway remodeling by inducing EMT. Therefore, new therapeutic approaches for the treatment of chronic asthma, could be aided by the development of agents that target the Sema7a.

Semaphorin-3A: a promising therapeutic tool in allergic rhinitis

Semaphorin-3A (Sema-3A), a secreted member of the semaphorin family, is well known for playing regulatory functions at all stages of the immune response. Sema-3A transduces signals by binding to its cognate receptors, namely, class A plexins (Plxns A1 to A4) and neuropilin-1 (Nrp-1). The downstream diverse signaling pathways induced by connecting Sema-3A to its receptors were found to be involved in the pathogenesis of different immunological disorders, ranging from cancer to autoimmunity and allergies. Recent studies have demonstrated that Sema-3A expression is diminished in the murine models and patients with allergic rhinitis (AR; a chronic inflammatory disorder of the nasal mucosa), suggesting the involvement of Sema-3A in AR pathogenesis. Investigations also revealed that treatment of these mice with exogenous Sema-3A protein alleviates the clinical symptom scores of AR, thereby compensating for the reduced expression of Sema-3A in AR. Indeed, Sema-3A treatment could suppress allergic responses in AR via inhibiting Th2/Th17 responses and boosting Th1/Treg responses. Also, Sema-3A could diminish dendritic cell (DC) maturation and T cell proliferation. Since it is implicated in the pathogenesis of AR; thus, Sema-3A turns to be a promising tool of therapy to be studied and utilized in this disease. This review intends to highlight the recent evidence on the role of Sema-3A in AR pathogenesis and summarizes the recent findings regarding the expression status of Sema-3A, as well as its therapeutic potential for treating this disease. HIGHLIGHTS: Sema-3A plays regulatory functions at all stages of the immune response. Sema-3A receptors are the class A plexins (A1-A4) and neuropilin-1 (Nrp-1). Sema-3A expression is reduced in murine models and patients with allergic rhinitis. Connecting Sema-3A to Nrp-1 increases Foxp3 expression in Treg cells. Injecting Sema-3A protein exerts therapeutic effects in mouse models of allergic diseases. Sema-3A shows promise as a therapeutic tool for the treatment of allergic rhinitis.

Modelling and Refining Neuronal Circuits with Guidance Cues: Involvement of Semaphorins

The establishment of neuronal circuits requires neurons to develop and maintain appropriate connections with cellular partners in and out the central nervous system. These phenomena include elaboration of dendritic arborization and formation of synaptic contacts, initially made in excess. Subsequently, refinement occurs, and pruning takes places both at axonal and synaptic level, defining a homeostatic balance maintained throughout the lifespan. All these events require genetic regulations which happens cell-autonomously and are strongly influenced by environmental factors. This review aims to discuss the involvement of guidance cues from the Semaphorin family.

The role of immune semaphorins in the pathogenesis of multiple sclerosis: Potential therapeutic targets

The immune and nervous systems possess a highly intricate network of synaptic connections, shared messenger molecules, and exquisite communication ways, allowing intercellular signal transduction. The semaphorins (Semas) were initially identified as axonal guidance molecules in the development of the nervous system but later were found to be implicated also in regulating the immune system, known in this case as the "immune Semas" or "immunoregulatory Semas". Increasingly, these molecules are involved in multiple aspects of both physiological and pathological immune responses and were recently indicated to take part in various immunological disorders, encompassing allergy, cancer, and autoimmunity. Semas transduce signals by connecting to their cognate receptors, namely, plexins and neuropilins. Some of them, like Sema-3F, have been found to function as the inducer of the remyelination process whereas some others, like Sema-3A and Sema-4D, act to inhibit this process, either directly or indirectly. Besides, Sema-4A is crucial to the differentiation of T helper type 1 (Th1) and Th17 cells that are potentially involved in the pathogenesis of multiple sclerosis (MS), an autoimmune disease of the central nervous system. This review aims to reveal the role of immune Semas in the pathogenesis of MS and its animal model, experimental autoimmune encephalomyelitis, focusing on the therapeutic usages of these molecules to treat this neurodegenerative disease.

Semaphorins and Plexins in central nervous system patterning: the key to it all?

Semaphorins and Plexins constitute one of the largest family of guidance molecules and receptors involved in setting critical biological steps for central nervous system development. The role of these molecules in axonal development has been extensively characterized but Semaphorins and Plexins are also involved in a variety of other developmental processes, spanning from cell polarization to migration, laminar segregation and neuronal maturation. In this review, we aim to gather discoveries carried in the field of neurodevelopment over the last decade, during which Semaphorin/Plexin complexes have emerged as key regulators of neurogenesis, neural cell migration and adult gliogenesis. As well, we report mechanisms that brought a better understanding of axonal midline crossing.