Files and links (1)
PDFOpen Access (License Unspecified), Open Access
Dissertation
A story of the AGEs: regulation of dermal fibroblast signaling by the precursor of advanced glycation end products 3-deoxyglucosone
Doctor of Philosophy (Ph.D.), Drexel University
Oct 2010
DOI:
https://doi.org/10.17918/00007918
Abstract
Advanced glycation end products occur through nonenzymatic glycation of long lived proteins such as collagens. One precursor to these modifications, 3-deoxyglucosone (3DG), is elevated in patients with diabetes and contributes to the accumulation of advanced glycation end products on collagen and may potentiate the poor wound healing observed in these patients. Since wound repair is dependent on fibroblast migration, proliferation, and expression of extracellular matrix proteins, we examined the role of 3DG-modified type I collagen and the subsequent response of dermal fibroblasts to this modification. Initial studies showed that 3DG-collagen reduced the expression of essential growth factors in fibroblasts. Furthermore, fibroblasts increased their adherence and reduced their migration on 3DG-collagen, which was dependent on the activation of [alpha]1[beta]1 integrin and growth factor receptor signaling. Also, studies showed that 3DG-collagen induced oxidative stress and caspase-3 activation. Oxidative stress was found to be dependent on the upregulation of NAD(P)H oxidase 4, triggering endoplasmic reticulum stress, as assessed by the ER stress-induced apoptosis marker Growth Arrest and DNA Damage-inducible gene 153 (GADD153). 3DG-collagen activated GADD153 and caspase-3 via phosphorylation of p38 mitogen activated protein kinase (MAPK), and this was dependent on upstream reactive oxygen species. Investigations also demonstrated that 3DG-collagen-induced caspase-3 activation did not signal through the canonical receptor for advanced glycation end products but through [alpha]1[beta]1 integrin. Neutralization of [alpha]1[beta]1 integrin prevented 3DG-collagen-induced upregulation of the ER stress pathway; suggesting that 3DG-collagen signaling to the fibroblast was dependent on [alpha]1[beta]1 integrin. Additional studies investigated the role of p38 MAPK in controlling cell growth in fibroblasts cultured on 3DG-collagen. Studies demonstrated that p38 MAPK can promote either cell growth or cell death, and that this was dependent upon activation of upstream H-ras and ASK1. Cell growth on native collagen was dependent on p38 MAPK phosphorylation of AKT and ERK1/2. In contrast, 3DG-collagen decreased fibroblast migration, proliferation, and collagen expression through ER1C1/2 and AKT downregulation via p38 MAPK. Finally, meglumine attenuated the effects of 3DG-collagen on dermal fibroblasts. Taken together, these data indicate that 3DG-collagen negatively impacts dermal fibroblast migration, proliferation, and survival, and may play a significant role in chronic diabetic wounds.
Metrics
20 File views/ downloads
15 Record Views
Details
- Title
- A story of the AGEs
- Creators
- Danielle T. Loughlin
- Contributors
- Carol Artlett (Advisor) - Drexel University, Drexel University (1970-)Elizabeth P. Blankenhorn (Advisor) - Drexel University, Drexel University (1970-)
- Awarding Institution
- Drexel University
- Degree Awarded
- Doctor of Philosophy (Ph.D.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- xix, 246 pages
- Resource Type
- Dissertation
- Language
- English
- Academic Unit
- Drexel University
- Other Identifier
- 991021889072104721