Related Experiment Videos
Defects in keratinocyte activation during wound healing in the syndecan-1-deficient mouse
Mary Ann Stepp1, Heather E Gibson, Purvi H Gala
1Department of Anatomy and Cell Biology, The George Washington University Medical School, Washington DC 20037, USA. mastepp@gwu.edu
Abstract:
Mice lacking syndecan-1 are viable, fertile and have morphologically normal skin, hair and ocular surface epithelia. While studying the response of these mice to corneal epithelial and skin wounding, we identified defects in epithelial cell proliferation and regulation of integrin expression. mRNA profiling of corneal epithelial tissues obtained from wild-type and syndecan-1(-/-) mice suggest that these defects result from differences in overall gene transcription. In the cornea, syndecan-1(-/-) epithelial cells migrate more slowly, show reduced localization of alpha9 integrin during closure of wounds and fail to increase their proliferation rate 24 hours after wounding. In the skin, we did not document a migration defect after full thickness wounds but did observe cell proliferation delays and reduced localization of alpha9 integrin in the syndecan-1(-/-) epidermis after dermabrasion. Despite increased cell proliferation rates in the uninjured syndecan-1(-/-) epidermis and the corneal epithelium, morphologically normal epithelial thickness is maintained prior to injury; however, wounding is accompanied by prolonged hypoplasia in both tissues. Analyses of integrin protein levels in extracts from full thickness skin, revealed increased levels of alpha3 and alpha9 integrins both prior to injury and after hair removal in syndecan-1(-/-) mice but no increase 2 days after dermabrasion. These data for the first time show involvement of alpha9 integrin in skin wound healing and demonstrate essential roles for syndecan-1 in mediating cell proliferation and regulation of integrin expression in normal and wounded epithelial tissues.
Insights
Mice lacking syndecan-1 show impaired epithelial wound healing, with delayed cell proliferation and altered alpha9 integrin expression in both skin and cornea. This highlights syndecan-1's crucial role in tissue repair.
Area of Science:
- Epithelial biology
- Wound healing research
- Integrin signaling
Background:
- Syndecan-1 is a cell surface proteoglycan involved in cell adhesion and signaling.
- Its specific role in epithelial wound repair, particularly in conjunction with integrins, remains incompletely understood.
Purpose of the Study:
- To investigate the function of syndecan-1 in epithelial wound healing.
- To determine the impact of syndecan-1 deficiency on cell proliferation, migration, and integrin expression during tissue repair.
Main Methods:
- Utilized genetically modified mice lacking syndecan-1 (syndecan-1-/-).
- Assessed corneal and skin wound healing responses, including cell proliferation, migration, and alpha9 integrin localization.
- Performed mRNA profiling and analyzed integrin protein levels in epithelial tissues.
Main Results:
- Syndecan-1 deficient mice exhibited delayed corneal epithelial cell proliferation and slower wound closure.
- Reduced alpha9 integrin localization was observed in wounded corneas and dermabraded skin of syndecan-1-/- mice.
- While basal proliferation was increased, wounding led to prolonged hypoplasia in syndecan-1 deficient tissues.
Conclusions:
- Syndecan-1 is essential for regulating epithelial cell proliferation and integrin expression during wound healing.
- The study demonstrates a novel involvement of alpha9 integrin in skin wound healing.
- These findings underscore syndecan-1's critical role in maintaining epithelial integrity and facilitating tissue repair.