Synergistic effects of osteonectin and brain-derived neurotrophic factor on axotomized retinal ganglion cells neurite outgrowth via the mitogen-activated protein kinase-extracellular signal-regulated kinase1/2 pathways

Neuroscience ◽  
2010 ◽  
Vol 165 (2) ◽  
pp. 463-474 ◽  
Author(s):  
C.H.E. Ma ◽  
E.T.W. Bampton ◽  
M.J. Evans ◽  
J.S.H. Taylor
Keyword(s):  
Protein Kinase ◽  
Neurite Outgrowth ◽  
Retinal Ganglion Cells ◽  
Neurotrophic Factor ◽  
Ganglion Cells ◽  
Synergistic Effects ◽  
Mitogen Activated Protein Kinase ◽  
Retinal Ganglion ◽  
Extracellular Signal ◽  
Mitogen Activated Protein

scholarly journals The Insulin Receptor: A Potential Target of Amarogentin Isolated from Gentiana rigescens Franch That Induces Neurogenesis in PC12 Cells

Biomedicines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 581
Author(s):  
Lihong Cheng ◽  
Hiroyuki Osada ◽  
Tianyan Xing ◽  
Minoru Yoshida ◽  
Lan Xiang ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Insulin Receptor ◽  
Signaling Pathways ◽  
Neurite Outgrowth ◽  
Pc12 Cells ◽  
Mitogen Activated Protein Kinase ◽  
Potential Target ◽  
Extracellular Signal ◽  
Mitogen Activated Protein ◽  
Gentiana Rigescens

Amarogentin (AMA) is a secoiridoid glycoside isolated from the traditional Chinese medicine, Gentiana rigescens Franch. AMA exhibits nerve growth factor (NGF)-mimicking and NGF-enhancing activities in PC12 cells and in primary cortical neuron cells. In this study, a possible mechanism was found showing the remarkable induction of phosphorylation of the insulin receptor (INSR) and protein kinase B (AKT). The potential target of AMA was predicted by using a small-interfering RNA (siRNA) and the cellular thermal shift assay (CETSA). The AMA-induced neurite outgrowth was reduced by the siRNA against the INSR and the results of the CETSA suggested that the INSR showed a significant thermal stability-shifted effect upon AMA treatment. Other neurotrophic signaling pathways in PC12 cells were investigated using specific inhibitors, Western blotting and PC12(rasN17) and PC12(mtGAP) mutants. The inhibitors of the glucocorticoid receptor (GR), phospholipase C (PLC) and protein kinase C (PKC), Ras, Raf and mitogen-activated protein kinase (MEK) significantly reduced the neurite outgrowth induced by AMA in PC12 cells. Furthermore, the phosphorylation reactions of GR, PLC, PKC and an extracellular signal-regulated kinase (ERK) were significantly increased after inducing AMA and markedly decreased after treatment with the corresponding inhibitors. Collectively, these results suggested that AMA-induced neuritogenic activity in PC12 cells potentially depended on targeting the INSR and activating the downstream Ras/Raf/ERK and PI3K/AKT signaling pathways. In addition, the GR/PLC/PKC signaling pathway was found to be involved in the neurogenesis effect of AMA.

scholarly journals 7,8-Dihydroxiflavone Protects Adult Rat Axotomized Retinal Ganglion Cells through MAPK/ERK and PI3K/AKT Activation

2021 ◽  
Vol 22 (19) ◽  
pp. 10896
Author(s):  
Caridad Galindo-Romero ◽  
Beatriz Vidal-Villegas ◽  
Javier Asís-Martínez ◽  
Fernando Lucas-Ruiz ◽  
Alejandro Gallego-Ortega ◽  
...  
Keyword(s):  
Retinal Ganglion Cells ◽  
Ganglion Cells ◽  
Mitogen Activated Protein Kinase ◽  
Retinal Ganglion ◽  
Sprague Dawley ◽  
Akt Activation ◽  
Adult Rat ◽  
Phosphorylated Akt ◽  
Mitogen Activated Protein ◽  
Signaling Activation

We analyze the 7,8-dihydroxyflavone (DHF)/TrkB signaling activation of two main intracellular pathways, mitogen-activated protein kinase (MAPK)/ERK and phosphatidylinositol 3 kinase (PI3K)/AKT, in the neuroprotection of axotomized retinal ganglion cells (RGCs). Methods: Adult albino Sprague-Dawley rats received left intraorbital optic nerve transection (IONT) and were divided in two groups. One group received daily intraperitoneal DHF (5 mg/kg) and another vehicle (1%DMSO in 0.9%NaCl) from one day before IONT until processing. Additional intact rats were employed as control (n = 4). At 1, 3 or 7 days (d) after IONT, phosphorylated (p)AKT, p-MAPK, and non-phosphorylated AKT and MAPK expression levels were analyzed in the retina by Western blotting (n = 4/group). Radial sections were also immunodetected for the above-mentioned proteins, and for Brn3a and vimentin to identify RGCs and Müller cells (MCs), respectively (n = 3/group). Results: IONT induced increased levels of p-MAPK and MAPK at 3d in DHF- or vehicle-treated retinas and at 7d in DHF-treated retinas. IONT induced a fast decrease in AKT in retinas treated with DHF or vehicle, with higher levels of phosphorylation in DHF-treated retinas at 7d. In intact retinas and vehicle-treated groups, no p-MAPK or MAPK expression in RGCs was observed. In DHF- treated retinas p-MAPK and MAPK were expressed in the ganglion cell layer and in the RGC nuclei 3 and 7d after IONT. AKT was observed in intact and axotomized RGCs, but the signal intensity of p-AKT was stronger in DHF-treated retinas. Finally, MCs expressed higher quantities of both MAPK and AKT at 3d in both DHF- and vehicle-treated retinas, and at 7d the phosphorylation of p-MAPK was higher in DHF-treated groups. Conclusions: Phosphorylation and increased levels of AKT and MAPK through MCs and RGCs in retinas after DHF-treatment may be responsible for the increased and long-lasting RGC protection afforded by DHF after IONT.

scholarly journals A Safe GDNF and GDNF/BDNF Controlled Delivery System Improves Migration in Human Retinal Pigment Epithelial Cells and Survival in Retinal Ganglion Cells: Potential Usefulness in Degenerative Retinal Pathologies

2021 ◽  
Vol 14 (1) ◽  
pp. 50
Author(s):  
Alicia Arranz-Romera ◽  
Maria Hernandez ◽  
Patricia Checa-Casalengua ◽  
Alfredo Garcia-Layana ◽  
Irene T. Molina-Martinez ◽  
...  
Keyword(s):  
Cell Viability ◽  
Retinal Ganglion Cells ◽  
Neurotrophic Factor ◽  
Retinal Pigment Epithelial ◽  
Ganglion Cells ◽  
Retinal Pigment ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Retinal Ganglion ◽  
Pigment Epithelial

We assessed the sustained delivery effect of poly (lactic-co-glycolic) acid (PLGA)/vitamin E (VitE) microspheres (MSs) loaded with glial cell-derived neurotrophic factor (GDNF) alone (GDNF-MSs) or combined with brain-derived neurotrophic factor (BDNF; GDNF/BDNF-MSs) on migration of the human adult retinal pigment epithelial cell-line-19 (ARPE-19) cells, primate choroidal endothelial (RF/6A) cells, and the survival of isolated mouse retinal ganglion cells (RGCs). The morphology of the MSs, particle size, and encapsulation efficiencies of the active substances were evaluated. In vitro release, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cell viability, terminal deoxynucleotidyl transferase (TdT) deoxyuridine dUTP nick-end labelling (TUNEL) apoptosis, functional wound healing migration (ARPE-19; migration), and (RF/6A; angiogenesis) assays were conducted. The safety of MS intravitreal injection was assessed using hematoxylin and eosin, neuronal nuclei (NeuN) immunolabeling, and TUNEL assays, and RGC in vitro survival was analyzed. MSs delivered GDNF and co-delivered GDNF/BDNF in a sustained manner over 77 days. The BDNF/GDNF combination increased RPE cell migration, whereas no effect was observed on RF/6A. MSs did not alter cell viability, apoptosis was absent in vitro, and RGCs survived in vitro for seven weeks. In mice, retinal toxicity and apoptosis was absent in histologic sections. This delivery strategy could be useful as a potential co-therapy in retinal degenerations and glaucoma, in line with future personalized long-term intravitreal treatment as different amounts (doses) of microparticles can be administered according to patients’ needs.

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