Anti‐Thy‐1 antibody‐induced neurite outgrowth in cultured dorsal root ganglionic neurons is mediated by the c‐Src‐MEK signaling pathway

Abstract

Our previous study has shown that anti-Thy-1 antibody promotes neurite outgrowth of cultured dorsal root ganglion (DRG) neurons in a protein kinase A (PKA)-dependent manner. The present study provided another intracellular signaling pathway for the neurotrophic effect of anti-Thy-1 antibody. In DMSO-treated control cells, Thy-1 was enriched in microdomain-like structures on cell membranes by immunofluorescence observation. Treatment of DRG neurons with anti-Thy-1 antibody not only stimulated neurite outgrowth, but also increased the branching complexity of the neurites in both small and large neurons. We have previously shown that anti-Thy-1 antibody causes a time-dependent activation of mitogen-activated protein kinase (MEK) and of cyclic AMP response-element binding protein (CREB). Here, anti-Thy-1 antibody elicited a transient activation of c-Src kinase, and the activation of c-Src kinase appeared occurring upstream of the activation of MEK and CREB, since pretreatment with the Src kinase inhibitor, PP2, effectively abolished the anti-Thy-1 antibody-induced neurite outgrowth and the phosphorylation of MEK and CREB. CREB phosphorylation might result in upregulation of certain neurite outgrowth-related proteins. We therefore conclude that anti-Thy-1 antibody activates the c-Src kinase-MEK-CREB cascade and overcomes the inhibitory effect of Thy-1 on neurite outgrowth in DRG neurons.

Daidzein induces neuritogenesis in DRG neuronal cultures

“…Src kinase, which is activated by various molecules like NGF, laminin, artemin, and anti-Thy-1 antibody, has been shown to be an important signaling pathway involved in the process of DRG neurite outgrowth [27,36,37]. Downstream signaling of Src includes MEK/ERK and PI3K/Akt pathways, which can be activated by NGF to induce neurite extension and branching of DRG neurons [38].…”

“…To further understand the diversity of the intracellular signaling mechanisms of daidzein, in the current study we focused on daidzein-induced neurite outgrowth in cultured DRG neurons. DRG culture is a well-characterized system for investigating the mechanism of neuritogenesis [25-27], and for screening neuroprotective drugs for peripheral neuropathies [28]. Studies using DRG cultures have shed light on the pathogenic mechanisms of peripheral nervous system diseases and the regeneration of spinal cord injury [29-31].…”

Roles and regulation of Thy‐1, a context‐dependent modulator of cell phenotype

“…For instance, Thy-1 is expressed on both peripheral T cells and thymocytes of mice; whereas in humans, Thy-1 is absent in the former and developmentally regulated in the latter [59]. Thy-1 modulates the phenotypes of cells implicated in several disease states including neuronal injury [30, 50, 68], pulmonary fibrosis [42, 47, 48], certain cancers [1, 14, 31], Graves' disease ophthalmopathy [22], and glomerulonephritis [34]. …”

Thy-1 Modulates Neurological Cell–Cell and Cell–Matrix Interactions Through Multiple Molecular Interactions

“…Signaling pathways leading to neurite outgrowth in this case include the activation of both protein kinase A (PKA) and Src, which affect the activation of the mitogen-activated protein kinase kinase/extracellular signal-regulated kinase/cAMP response element-binding protein (MEK/Erk/CREB) pathway, although a direct link between Thy-1 engagement by antibodies and these signaling cascades has not been confi rmed (Chen et al 2007 ;Yang et al 2008 ). Improved understanding of the molecular mechanisms involved in Thy-1-mediated neurite outgrowth inhibition may help in designing interventions to block the negative effects of Thy-1 on the repair of neuronal processes.…”