Gnrh Migration Is Influenced By The Interaction Of Myo X And N-Cadherin

Gonadotropin-releasing hormone (GnRH) neurons arise from the olfactory placode, along olfactory axons,move through the cribriform plate, migrate past the olfactory bulb (OB), and then proceed deeper into the developing forebrain. In the forebrain, the GnRH cells secrete the hormone of GnRH, which is an important regulatory factor to reproductive axis in brain and plays an essential role to regulate the pituitary-gonadal axis function. Therefore, it's very important for the development of vertebrate reproductive maturation and maintenance of reproductive function that GnRH neurons migrate to the correct location. As a non-traditional form of myosin, Myo X plays important roles in some processes, such as filopodia formation, cell adhesion, polarity establishment and cell migration. Previous studies in our lab have demonstrated that inhibition the expression of Myo X lead to the loss of cell polarity. Studies have shown that MyoX interacted, via its FERM domain, with the VE-Cadherin complex, then transported it along flopodia to the tip. The accumulation of VE-Cadherin at flopodium tips is an important event probably involved in the early stage of adhesion. N-Cadherin is one important member of the transmembrane glycoprotein cadherin family, has a high degree of homology with VE-Cadherin . So we speculated that N-Cadherin might have similar functions as VE-Cadherin , play an important role in the establishment of adhesion formation and polarity establishment by interacting with Myo X. So we want to explore the roles of Myo X and N-Cadherin in the process of GnRH neuronal migration, then reveal the molecule mechanism of GnRH neuronal migration.In our study, firstly we detected Myo X interacts with N-Cadherin via its FERM domain by co-immunoprecipitation; Secondly we inhibited the expression of Myo X in NLT cells, then found cell adhesion and cell cytoskeleton are affected, and the cell adhesion between cells and matrix are weaken, the density of vinculin in scramble miRNA-NLT cells was 0.097±0.00021piece/μm2, however the density depressed to 0.052±0.00017piece/μm2 in MyoΧmiRNA-NLT cells; The density of F-actin in scramble miRNA-NLT cells was 0.0043±0.00012 piece/μm2, however, it depressed to 0.0027±0.00015 piece/μm2 by knockdown Myo X. Real-time PCR was used to analyze differential expression of N-cadherin mRNA in Scramble miRNA-NLT cells and MyoΧmiRNA-NLT cells, mRNA of N-Cadherin reduced to 52.40% compared to Scramble miRNA-NLT cells; Moreover, western blot analysising revealed that expression of N-cadherin was down regulation in Myo X miRNA cells. Cell aggregate assay indicated that silence the expression of Myo X decreased cells migrate from cell aggregation by radial way and then reduced migration distance, but the phenotype variation caused by knockdown of Myo X could be rescued by the over-expression of N-Cadherin. These results suggested that Myo X interacted with N-Cadherin and then regulated the migration of GnRH neurons, these results provided some theoretical basis for further clarify the mechanism of GnRH neuron migration.