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Updated: Oct 4, 2026
Ganglioside Extraction, Purification and Profiling
Published on: March 12, 2021
Enhancement of epidermal growth factor signaling and activation of SRC kinase by gangliosides
1Glycobiology Program, Center for Cancer and Transplantation Biology, Children's Research Institute, Washington, DC 20010, USA. ruixiangli@msn.com
Abstract:
In a recent study, inhibition of cellular ganglioside synthesis blocked growth factor-induced fibroblast proliferation. Conversely, enrichment of cell membrane gangliosides by ganglioside preincubation enhanced growth factor-elicited cell proliferation. In the absence of serum and growth factors, NeuNAcalpha2-3Galbeta1-3GalNAcbeta1-4(NeuNAcalpha2-3)Galbeta1-4Glcbeta1-1Cer (G(D1a)) acted like a growth factor when cells were pretreated with the ganglioside, stimulating proliferation of normal human dermal fibroblasts and Swiss 3T3 fibroblasts. In contrast, growth inhibition was observed when high concentrations of gangliosides were continuously present in the culture medium during incubation of fibroblasts with growth factors (Li, R., Manela, J., Kong, Y., and Ladisch, S. (2000) J. Biol. Chem. 275, 34213-34223). Here, we investigated the mechanisms whereby gangliosides elicit proliferation-coupled signaling in normal human dermal fibroblasts. Incubation of the fibroblasts with G(D1a) enhanced epidermal growth factor (EGF) receptor autophosphorylation and Ras and MAPK activation in a dose-dependent manner. Exposure of the cells to G(D1a) also enhanced the phosphorylation of Elk-1 by the activated MAPK. Brief pretreatment of the cells with PD98059 blocked the enhancing effect of gangliosides on EGF-induced MAPK activation. In the absence of serum and growth factors, G(D1a) incubation induced phosphorylation of Src kinase, Ras activation, and phosphorylation of MAPK and Elk-1 in a dose-dependent manner. The activation of Src kinase was confirmed by enhanced Src kinase activity. Brief treatment of the cells with PP1 blocked the activation of Src kinase and MAPK. Again, PD98059 treatment inhibited ganglioside-elicited MAPK phosphorylation. Among the gangliosides tested, G(D1a), was the most active molecule, whereas lactosylceramide was the least active one, indicating relative structural specificity of the ganglioside action. In conclusion, gangliosides promote fibroblast proliferation through enhancement of growth factor signaling and activation of Src kinase.
Insights
Gangliosides, like G(D1a), stimulate fibroblast proliferation by enhancing growth factor signaling pathways, including epidermal growth factor receptor (EGFR) and mitogen-activated protein kinase (MAPK) activation. This study reveals gangliosides
Area of Science:
- Cell Biology
- Biochemistry
- Molecular Signaling
Background:
- Cellular gangliosides play a role in fibroblast proliferation, with their synthesis inhibition blocking growth factor-induced proliferation.
- Enrichment of cell membrane gangliosides enhances growth factor-elicited fibroblast proliferation.
- Specific gangliosides, such as G(D1a), can act as growth factors in the absence of serum and external growth factors.
Purpose of the Study:
- To investigate the mechanisms by which gangliosides elicit proliferation-coupled signaling in normal human dermal fibroblasts.
- To elucidate the role of gangliosides in epidermal growth factor (EGF) receptor signaling and downstream pathways.
- To determine the involvement of Src kinase and mitogen-activated protein kinase (MAPK) in ganglioside-mediated fibroblast proliferation.
Main Methods:
- Dose-dependent analysis of ganglioside (G(D1a)) effects on EGF receptor autophosphorylation, Ras, and MAPK activation.
- Assessment of Elk-1 phosphorylation by activated MAPK following ganglioside treatment.
- Inhibition studies using PD98059 and PP1 to block specific signaling pathways (MAPK and Src kinase, respectively).
- Evaluation of Src kinase activity and dose-dependent effects of G(D1a) in serum- and growth factor-free conditions.
Main Results:
- G(D1a) enhanced EGF receptor autophosphorylation, Ras, and MAPK activation in a dose-dependent manner.
- Ganglioside treatment led to increased phosphorylation of Elk-1 by MAPK.
- In serum- and growth factor-free conditions, G(D1a) induced Src kinase phosphorylation, Ras activation, and subsequent MAPK and Elk-1 phosphorylation.
- Src kinase activation was confirmed by enhanced kinase activity.
- PD98059 and PP1 treatments effectively blocked ganglioside-induced MAPK and Src kinase activation, respectively.
- G(D1a) demonstrated higher activity than lactosylceramide, indicating structural specificity.
Conclusions:
- Gangliosides promote fibroblast proliferation by enhancing growth factor signaling pathways.
- Activation of Src kinase is a key mechanism in ganglioside-mediated fibroblast proliferation.
- Gangliosides modulate EGF receptor signaling, leading to downstream activation of Ras and MAPK pathways.
- The findings highlight the specific structural requirements of gangliosides for eliciting proliferative signals.
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