Etifoxine promotes glial-derived neurotrophic factor-induced neurite outgrowth in PC12 cells

Abstract

Abstract. Nerve regeneration and functional recovery are major issues following nerve tissue damage. Etifoxine is currently under investigation as a therapeutic strategy for promoting neuroprotection, accelerating axonal regeneration and modulating inflammation. In the present study, a well-defined PC12 cell model was used to explore the underlying mechanism of etifoxine-stimulated neurite outgrowth. Etifoxine was found to promote glial-derived growth factor (GDNF)-induced neurite outgrowth in PC12 cells. Average axon length increased from 50.29±9.73 to 22.46±5.62 µm with the use of etifoxine. However, blockage of GDNF downstream signaling was found to lead to the loss of this phenomenon. The average axon length of the etifoxine group reduces to a normal level after the blockage of the GDNF family receptor α1 (GFRα1) and receptor tyrosine kinase (RETS) receptors (27.46 ± 3.59 vs. 22.46 ± 5.62 µm and 25.31±3.68 µm vs. 22.46±5.62 µm, respectively, p>0.05). In addition, etifoxine markedly increased GDNF mRNA and protein expression (1.55-and 1.36-fold, respectively). However, blockage was not found to downregulate GDNF expression. The results of the current study demonstrated that etifoxine stimulated neurite outgrowth via GDNF, indicating that GDNF represents a key molecule in etifoxine-stimulated neurite outgrowth in PC12 cells. IntroductionTraumatic injury to peripheral nerves results in considerable loss of sensory and motor function, decreasing quality of life in patients (1). Peripheral nerve injuries substantially impact quality of life through loss of function and increased risk of secondary disabilities from falls, fractures and other injuries. Several research groups have attempted to improve the regeneration of traumatized nerves by developing favorable microsurgical techniques. However, clinicians soon noted that despite advancement in these techniques, complete recovery is rarely achieved (2,3). Therefore, complete recovery remains an important clinical challenge for the improvement of functional recovery following peripheral nerve injury. In a discussion of future trends in the management of brachial plexus injuries, Birch hypothesized that the administration of nerve growth factor may represent a useful treatment strategy (4).Neurotrophic factors are important in a number of biological processes, including survival, proliferation, differentiation and apoptosis of neurons in the nervous system (5-7). However, direct use of trophic factors in clinical practice is extremely challenging as they are difficult to administer and have severe side effects (8). However, molecules that easily diffuse into nerve tissues, including ligands of the progesterone and thyroid hormone receptors, and immunophilins, have beneficial effects on peripheral nerves in various experimental lesion and disease models (9-12). We hypothesize that clinically established drugs may be suitable to elevate trophic factor levels to improve the outcome of peripheral nerve injuries.Previous studies have demonstrated that the drug, etifoxi...

A genetic pedigree analysis to identify gene mutations involved in femoral head necrosis

“…Genomic DNA was extracted from 5 ml of peripheral blood using EDTA as an anticoagulant according to a method previously described with little modification (10). The concentration and purity of the genomic DNA were assessed in a UV spectrophotometer (Tecan, San Diego, CA, USA) at 260/280 nm.…”

Neurotrophic Effects of Etifoxine

“…В культуре нейронов этифоксин способствовал росту GDNF-регулируемых нейритов: средняя длина аксона уве-личилась с 22±6 до 50±9 мкм; достоверно повысился и уро-вень мРНК GDNF (в 1,6 раза) и белка GDNF (в 1,4 раза) [14]. При этом ингибирование GDNF-зависимых внутри-клеточных сигнальных каскадов приводило к потере эффе-кта этифоксина.…”

“…торов рецепторов GDNF, фосфоинозитидной фосфолипазы C PI-PLC (блокирует сигнал с помощью GFRα1) и ингиби-тора PRI-1 (блокирует рецептор RET-тирозинкиназу) под-твердило влияние этифоксина через GDNF-рецепторы GFRα1 и RET [14].…”

Etifoxine Promotes Glia-Derived Neurite Outgrowth In Vitro and In Vivo

“…Real-time polymerase chain reaction (RT-PCR) was performed as previously described. 12 Total RNA was extracted from 1 Â 10 6 cells. First strand cDNA was synthesized from total RNA (1 mg) using avian myeloblastosis virus reverse transcriptase (RT) XL primed by 50 pmol of random 9-mers (TaKaRa Biomedicals, Tokyo, Japan).…”

“…11 Zhou et al speculated that TSPO activation will lead to an increase of steroidogenesis and that increased steroids may affect glia-derived neurotrophic factor (GDNF) gene expression through cAMP-response element binding protein (CREB) phosphorylation. Moreover, etifoxine stimulated GDNF-induced neurite outgrowth in PC12 cells, 12 but details surrounding optimal therapeutic etifoxine concentrations are still lacking.…”