Search results for "Semaphorins"
showing 9 items of 9 documents
Semaphorins in Adult Nervous System Plasticity and Disease
2021
Semaphorins, originally discovered as guidance cues for developing axons, are involved in many processes that shape the nervous system during development, from neuronal proliferation and migration to neuritogenesis and synapse formation. Interestingly, the expression of many Semaphorins persists after development. For instance, Semaphorin 3A is a component of perineuronal nets, the extracellular matrix structures enwrapping certain types of neurons in the adult CNS, which contribute to the closure of the critical period for plasticity. Semaphorin 3G and 4C play a crucial role in the control of adult hippocampal connectivity and memory processes, and Semaphorin 5A and 7A regulate adult neuro…
New functions of Semaphorin 3E and its receptor PlexinD1 during developing and adult hippocampal formation
2018
AbstractThe development and maturation of cortical circuits relies on the coordinated actions of long and short range axonal guidance cues. In this regard, the class 3 semaphorins and their receptors have been seen to be involved in the development and maturation of the hippocampal connections. However, although the role of most of their family members have been described, very few data about the participation of Semaphorin 3E (Sema3E) and its receptor PlexinD1 during the development and maturation of the entorhino-hippocampal (EH) connection are available. In the present study, we focused on determining their roles both during development and in adulthood. We determined a relevant role for…
Reduced Sympathetic Innervation in Endometriosis is Associated to Semaphorin 3C and 3F Expression
2016
Endometriosis is a chronic inflammatory disease and one of the most common causes of pelvic pain. The mechanisms underlying pain emergence or chronic inflammation during endometriosis remain unknown. Several chronic inflammatory diseases including endometriosis show reduced amounts of noradrenergic nerve fibers. The source of the affected innervation is still unclear. Semaphorins represent potential elicitors, due to their known role as axonal guidance cues, and are suggested as nerve repellent factors in different chronic inflammatory diseases. Therefore, semaphorins might influence the progress of neuroinflammatory mechanisms during endometriosis. Here, we analyzed the noradrenergic inner…
Semaphorin and plexin gene expression is altered in the prefrontal cortex of schizophrenia patients with and without auditory hallucinations
2015
Auditory hallucinations (AH) are clinical hallmarks of schizophrenia, however little is known about molecular genetics of these symptoms. In this study, gene expression profiling of postmortem brain samples from prefrontal cortex of schizophrenic patients without AH (SNA), patients with AH (SA) and control subjects were compared. Genome-wide expression analysis was conducted using samples of three individuals of each group and the Affymetrix GeneChip Human-Gene 1.0 ST-Array. This analysis identified the Axon Guidance pathway as one of the most differentially expressed network among SNA, SA and CNT. To confirm the transcriptome results, mRNA level quantification of seventeen genes involved i…
Semaphorin 6A Improves Functional Recovery in Conjunction with Motor Training after Cerebral Ischemia
2010
Stroke is a major health problem in industrialized societies. Despite numerous attempts at developing acute stroke therapies aimed at minimizing acute infarct development, the only approved therapy so far is recombinant tissue plasminogen activator (rtPA). In recent years, the attention of the stroke community has therefore also put increased emphasis on understanding processes of post-stroke recovery, and their potential exploitability for therapeutic purposes. The brain has a remarkable ability to adapt to changes after stroke. Mechanisms that contribute to this plasticity are re-mapping and expansion of cortical areas to neighboring regions of functional motor cortex areas after injury […
A de novo microdeletion of SEMA5A in a boy with autism spectrum disorder and intellectual disability.
2016
AbstractSemaphorins are a large family of secreted and membrane-associated proteins necessary for wiring of the brain. Semaphorin 5A (SEMA5A) acts as a bifunctional guidance cue, exerting both attractive and inhibitory effects on developing axons. Previous studies have suggested that SEMA5A could be a susceptibility gene for autism spectrum disorders (ASDs). We first identified a de novo translocation t(5;22)(p15.3;q11.21) in a patient with ASD and intellectual disability (ID). At the translocation breakpoint on chromosome 5, we observed a 861-kb deletion encompassing the end of the SEMA5A gene. We delineated the breakpoint by NGS and observed that no gene was disrupted on chromosome 22. We…
Plexin-B1 and Semaphorin 4D Cooperate to Promote Perineural Invasion in a RhoA/ROK-Dependent Manner
2012
Perineural invasion (PNI) is a tropism of tumor cells for nerve bundles located in the surrounding stroma. It is a pathological feature observed in certain tumors, referred to as neurotropic malignancies, that severely limits the ability to establish local control of disease and results in pain, recurrent growth, and distant metastases. Despite the importance of PNI as a prognostic indicator, its biological mechanisms are poorly understood. The semaphorins and their receptors, the plexins, compose a family of proteins originally shown to be important in nerve cell adhesion, axon migration, and proper central nervous system development. Emerging evidence has demonstrated that these factors a…
Rho-mediated activation of PI(4)P5K and lipid second messengers is necessary for promotion of angiogenesis by Semaphorin 4D
2011
Phosphatidylinositol 4-phosphate 5-kinase (PI(4)P5K) is a type I lipid kinase that generates the lipid second messenger phospholipid phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) and functions downstream of RhoA in actin organization. It is known to play an essential role in neurite remodeling, yielding a phenotype identical to that seen in cells treated with Semaphorin 4D (Sema4D), a protein that regulates proliferation, adhesion and migration in many different cell types. Plexin-B1, the receptor for Sema4D, activates RhoA in order to generate a pro-angiogenic signal in endothelial cells. Therefore, we looked in human umbilical vein endothelial cells (HUVEC) to determine if Plexin-B1 e…
The hypoxia-inducible factor-responsive proteins semaphorin 4D and vascular endothelial growth factor promote tumor growth and angiogenesis in oral s…
2012
Growth and metastasis of solid tumors requires induction of angiogenesis to ensure the delivery of oxygen, nutrients and growth factors to rapidly dividing transformed cells. Through either mutations, hypoxia generated by cytoreductive therapies, or when a malignancy outgrows its blood supply, tumor cells undergo a change from an avascular to a neovascular phenotype, a transition mediated by the hypoxia-inducible factor (HIF) family of transcriptional regulators. Vascular endothelial growth factor (VEGF) is one example of a gene whose transcription is stimulated by HIF. VEGF plays a crucial role in promoting tumor growth and survival by stimulating new blood vessel growth in response to suc…