Semaphorin-neuropilin-1 interactions in plasticity and regeneration of adult neurons.
Gavazzi I
Cell and tissue research
During development, axonal growth cones are guided to their appropriate targets by many attractive and repulsive cues. It has become increasingly clear over the last few years that how the growth cone responds to these cues depends both on the molecular nature of the cue and on the internal state of the neuron. The unexpected result is that the same molecule can act as an attractor or as a repellent. A number of guidance cues used by neurons during development are retained in the adult nervous system, where their function is often still unclear. Most of these molecules are implicated in plasticity in the adult nervous system and can play a role (sometimes maladaptive) in neuronal regeneration after injury. A group of axonal guidance cues that has been well studied in development is the semaphorin family of secreted and membrane-anchored proteins, which has been implicated in axon steering, fasciculation, branching and synapse formation. This review focuses on semaphorin-3A (probably the best-characterized semaphorin) and its receptors (in particular neuropilin-1) in the adult nervous system and argues that semaphorin-3A plays a role in the maintenance and regeneration of adult sensory neurons.
10.1007/s004410100365
Long non-coding RNA Gm11974 aggravates oxygen-glucose deprivation-induced injury via miR-122-5p/SEMA3A axis in ischaemic stroke.
Metabolic brain disease
Long non-coding RNAs (lncRNAs) play important roles in ischaemic stroke. This study aimed to investigate the role and potential mechanism of lncRNA Gm11974 in ischaemic stroke. Mouse neuroblastoma N2a cells were treated with oxygen-glucose deprivation (OGD). The levels of Gm11974, microRNA-122-5p (miR-122-5p) and semaphorin 3A (SEMA3A) were detected by quantitative real-time PCR (qRT-PCR) or western blot. Cell viability and apoptosis were determined by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay, Caspase-3 Assay Kit and flow Cytometry. The levels of oxidative stress indicators were measured by using commercial kits. The relationship between miR-122-5p and Gm11974 or SEMA3A was verified by dual-luciferase reporter, RNA immunoprecipitation and RNA pull-down assays. Middle cerebral artery occlusion (MCAO) in mice was used to mimic ischaemic stroke. Gm11974 and SEMA3A were up-regulated, while miR-122-5p was down-regulated in OGD-treated N2a cells and MCAO mice. Down-regulation of Gm11974 ameliorated OGD-mediated N2a cell damage by increasing cell viability and reducing cell apoptosis and oxidative stress. Gm11974 promoted OGD-induced injury in N2a cells via negatively regulating miR-122-5p. Also, miR-122-5p alleviated OGD-resulted N2a cell injury by targeting SEMA3A. Moreover, silencing of Gm11974 decreased infarct volume and neurological score in MCAO mice. Knockdown of Gm11974 attenuated neuronal injury in ischaemic stroke by regulating miR-122-5p/SEMA3A signaling pathway.
10.1007/s11011-021-00792-7
Disruption of Sema3A/Plexin-A1 inhibitory signalling in oligodendrocytes as a therapeutic strategy to promote remyelination.
Binamé Fabien,Pham-Van Lucas D,Spenlé Caroline,Jolivel Valérie,Birmpili Dafni,Meyer Lionel A,Jacob Laurent,Meyer Laurence,Mensah-Nyagan Ayikoé G,Po Chrystelle,Van der Heyden Michaël,Roussel Guy,Bagnard Dominique
EMBO molecular medicine
Current treatments in multiple sclerosis (MS) are modulating the inflammatory component of the disease, but no drugs are currently available to repair lesions. Our study identifies in MS patients the overexpression of Plexin-A1, the signalling receptor of the oligodendrocyte inhibitor Semaphorin 3A. Using a novel type of peptidic antagonist, we showed the possibility to counteract the Sema3A inhibitory effect on oligodendrocyte migration and differentiation in vitro when antagonizing Plexin-A1. The use of this compound in vivo demonstrated a myelin protective effect as shown with DTI-MRI and confirmed at the histological level in the mouse cuprizone model of induced demyelination/remyelination. This effect correlated with locomotor performances fully preserved in chronically treated animals. The administration of the peptide also showed protective effects, leading to a reduced severity of demyelination in the context of experimental autoimmune encephalitis (EAE). Hence, the disruption of the inhibitory microenvironmental molecular barriers allows normal myelinating cells to exert their spontaneous remyelinating capacity. This opens unprecedented therapeutic opportunity for patients suffering a disease for which no curative options are yet available.
10.15252/emmm.201910378
Voltage-gated calcium and sodium channels mediate Sema3A retrograde signaling that regulates dendritic development.
Yamashita Naoya,Aoki Reina,Chen Sandy,Jitsuki-Takahashi Aoi,Ohura Shunsuke,Kamiya Haruyuki,Goshima Yoshio
Brain research
Growing axons rely on local signaling at the growth cone for guidance cues. Semaphorin3A (Sema3A), a secreted repulsive axon guidance molecule, regulates synapse maturation and dendritic branching. We previously showed that local Sema3A signaling in the growth cones elicits retrograde retrograde signaling via PlexinA4 (PlexA4), one component of the Sema3A receptor, thereby regulating dendritic localization of AMPA receptor GluA2 and proper dendritic development. In present study, we found that nimodipine (voltage-gated L-type Ca(2+) channel blocker) and tetrodotoxin (TTX; voltage-gated Na(+) channel blocker) suppress Sema3A-induced dendritic localization of GluA2 and dendritic branch formation in cultured hippocampal neurons. The local application of nimodipine or TTX to distal axons suppresses retrograde transport of Venus-Sema3A that has been exogenously applied to the distal axons. Sema3A facilitates axonal transport of PlexA4, which is also suppressed in neurons treated with either TTX or nimodipine. These data suggest that voltage-gated calcium and sodium channels mediate Sema3A retrograde signaling that regulates dendritic GluA2 localization and branch formation.
10.1016/j.brainres.2015.11.034