Keratinocytes express fibrillin and assemble microfibrils: implications for dermal matrix organization

Area of Science:

• Dermatology
• Cell Biology
• Extracellular Matrix Biology

Background:

• Fibrillin-containing microfibrils are vital for the upper dermis and elastic fiber network.
• These microfibrils connect the dermal elastic network to the epidermis at the dermal-epithelial junction.
• The cellular source of microfibrils at the dermal-epidermal junction was previously undefined.

Purpose of the Study:

• To investigate the potential role of keratinocytes in depositing microfibril bundles at the dermal-epidermal junction.
• To determine if keratinocytes synthesize fibrillin-1 and fibrillin-2.

Main Methods:

• Analysis of fresh human and porcine skin tissues.
• Isolation and culture of primary human and porcine keratinocytes.
• Immunohistochemical studies to detect fibrillin-1, fibrillin-2, and basement membrane collagen.

Main Results:

• Keratinocytes in vivo and in vitro synthesize both fibrillin-1 and fibrillin-2.
• Keratinocytes assemble beaded microfibrils.
• Microfibril assembly occurs concurrently with the expression of basement membrane collagen by keratinocytes.

Conclusions:

• Keratinocytes are responsible for the synthesis and deposition of fibrillin-containing microfibrils at the dermal-epidermal junction.
• Keratinocytes coordinate the secretion, deposition, and assembly of dermal matrix components.
• These findings have significant implications for understanding skin remodeling processes.