Repulsive guidance molecule a suppresses seizures and mossy fiber sprouting via the FAK‑p120RasGAP‑Ras signaling pathway

Abstract

Repulsive guidance molecule a (RGMa) is a membrane-associated glycoprotein that regulates axonal guidance and inhibits axon outgrowth. In our previous study, we hypothesized that RGMa may be involved in temporal lobe epilepsy (TLE) via the repulsive guidance molecule a (RGMa)-focal adhesion kinase (FAK)-Ras signaling pathway. To investigate the role of RGMa in epilepsy, recombinant RGMa protein and FAK inhibitor 14 was intracerebroventricularly injected into a pentylenetetrazol (PTZ) kindling model and Timm staining, co-immunoprecipitation and western blotting analyses were subsequently performed. The results of the present study revealed that intracerebroventricular injection of recombinant RGMa protein reduced the phosphorylation of FAK (Tyr397) and intracerebroventricular injection of FAK inhibitor 14 reduced the interaction between FAK and p120GAP, as wells as Ras expression. Recombinant RGMa protein and FAK inhibitor 14 exerted seizure-suppressant effects; however, recombinant RGMa protein but not FAK inhibitor 14 suppressed mossy fiber sprouting in the PTZ kindling model. Collectively, these results demonstrated that RGMa may be considered as a potential therapeutic agent for epilepsy, and that RGMa may exert the aforementioned biological effects partly via the FAK-p120GAP-Ras signaling pathway.

iTRAQ‐based proteomic analysis of the hippocampus of pentylenetetrazole‐kindled epileptic rats

“…The hippocampus exhibits a wide range of epilepsy‐related abnormalities, such as hippocampal sclerosis and mossy fiber sprouting (Thom, 2014). Our previous studies in pentylenetetrazole (PTZ)‐kindled rat models demonstrated that at approximately 28 days, the rats showed obvious spontaneous recurrent seizures, and prominent mossy fiber sprouting appeared in the CA3 area (Song et al., 2019; Tian et al., 2009). Proteomic analysis of the hippocampus of epileptic rats could help to reveal the molecular mechanisms underlying these pathological changes.…”

Silencing miR‐20a‐5p inhibits axonal growth and neuronal branching and prevents epileptogenesis through RGMa‐RhoA‐mediated synaptic plasticity

“…Emerging evidence has indicated that RGMa inhibits MFS and epileptogenesis 7‐9 . To identify the upstream regulators of RGMa, we performed a non‐biased search of in silico databases and intersected this information with publicly available miRNA profiles that potentially bind the 3'UTR of RGMa.…”

“…Through the efforts of several generations of researchers, the mechanisms of epilepsy development have begun to be revealed. For example, RGMa prevents epileptogenesis and reduces seizure severity by inhibiting MFS in epilepsy animal models 7‐9 . However, the upstream regulators of RGMa in epileptogenesis have remained unknown.…”

“…Emerging evidence has indicated that RGMa inhibits MFS and epileptogenesis. [7][8][9] To identify the upstream regulators of RGMa, we performed a non-biased search of in silico databases and intersected this information with publicly available miRNA profiles that potentially bind the 3'UTR of RGMa. Among the twenty-three miRNAs identified in all three databases, four miRNAs with relatively higher scores, including miR-106b-5p, miR-148b-3p, miR-152-3p and miR-20a-5p, were selected as potential candidates ( Figure 1A) and their levels were measured in rats of the NC and PTZ groups by RT-qPCR at 3 and 14 days.…”

“…In patients with epilepsy, a microdeletion of the chromosome encompassing the RGMa gene is a potential candidate contributing to epileptogenesis 5,6 ; in animal epilepsy models, growing evidence has shown that RGMa negatively controls epileptogenesis by inhibiting mossy fibre sprouting (MFS). [7][8][9] In addition, RGMa inhibits synaptic plasticity in the central nervous system 10 and synaptic plasticity promotes epileptogenesis. 11,12 However, whether RGMa is involved in epileptogenesis by regulating synaptic plasticity remains unknown.…”