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Immunolocalization of beta 1 integrins in human gingival epithelium and cultured keratinocytes
1Department of Periodontics, University of Alabama School of Dentistry, Birmingham.
Insights
Beta 1 integrins, crucial for cell adhesion, are found in human gingival keratinocytes. These receptors play a key role in cell-cell binding, especially in high calcium conditions.
Area of Science:
- Cell Biology
- Dermatology
- Integrin Biology
Background:
- Beta 1 integrins are cell surface receptors primarily known for extracellular matrix binding.
- Recent findings suggest a role for beta 1 integrins in cell-cell binding within human epidermal keratinocytes.
Purpose of the Study:
- To investigate the localization and role of beta 1 integrins in human gingival keratinocytes.
- To understand how calcium levels influence beta 1 integrin distribution and function in these cells.
Main Methods:
- Immunofluorescence microscopy
- Confocal laser scanning microscopy (CLSM)
- Analysis of human gingival tissue and cultured keratinocytes under varying calcium conditions
Main Results:
- Beta 1 integrins were primarily detected in the basal layer of the keratinized epithelium and at lateral cell membranes of basal keratinocytes.
- In low calcium, beta 1 integrins appeared in trails, dots, and cell-cell contacts, with trails containing fibronectin and type IV collagen.
- High calcium conditions promoted cell-cell contacts strongly positive for beta 1 integrins, but lacking fibronectin and type IV collagen.
Conclusions:
- Beta 1 integrins are present in human gingival keratinocytes and are involved in cell-cell adhesion.
- Calcium concentration significantly impacts the localization and function of beta 1 integrins in keratinocyte interactions.
Abstract:
Beta 1 integrins are cell surface receptors for extracellular matrix binding. We have recently shown that these receptors may also play a role in cell-cell binding of human epidermal keratinocytes. In this study we used immunofluorescence and confocal laser scanning microscopy to localize beta 1 integrins in frozen sections of human gingiva and cultures of human gingival keratinocytes. The results show that beta 1 integrin polypeptides, localized by monoclonal and polyclonal antibodies, were detected mainly in the basal layer of the keratinized epithelium. There was also scattered staining in connective tissue fibroblasts, nerves, and blood vessel walls. In the basal layer, the integrins were found around the entire periphery of the basal keratinocytes. Furthermore, confocal laser scanning microscopy (CLSM) revealed that most of the staining was in fact localized in dot-like structures at the lateral cell membranes of neighboring basal cells. In cultured human gingival keratinocytes maintained in low calcium (0.15 mM) conditions beta 1 integrins were localized in several different structures: trails which were left behind when the cells moved in culture, dots underneath the cells, around the nucleus, and in cell-cell contacts. The trails were also found to contain fibronectin and type IV collagen but not laminin. Switching the keratinocytes to high calcium (1.2 mM) conditions induced the formation of cell-cell contacts which were strongly positive for beta 1 integrins. No fibronectin or type IV collagen was found in cell-cell contact sites.(ABSTRACT TRUNCATED AT 250 WORDS)