Medical research

Skin graft: a new molecular target for activating stem cells

Human skin completely renews itself every month thanks to the presence of stem cells in the deepest layer, which generate all the upper layers of this tissue. The deciphering of genes that regulate stemness remains an enigma ...

Medical research

Signals from skin cells control fat cell specialization

Cells can change to a more specialized type in a process called cellular differentiation. Scientists have revealed that protein secretions by skin cells known as keratinocytes control the differentiation of subsurface skin ...

Medical research

A critical factor for wound healing

The p53 family of transcription factors (p63 and p73) plays critical roles in keratinocyte (skin cell) function.

Medical research

A fully human system to cultivate skin cells for grafting

Breakthrough study to culture human skin cells called keratinocytes to produce skin grafts has been published by a team of researchers from Duke-NUS Medical School and the Singapore General Hospital (SGH). This method is ...

Medical research

Research team lays bare melanin's DNA guarding mechanism

With a little help from chickens and video cameras, scientists have captured live the moment when skin gets darker. In a study appearing in Scientific Reports, a Japanese team has filmed and demystified the process by which ...

Immunology

Closer to the source of the itch

Psoriasis is an inflammatory skin condition that affects some 125 million people worldwide. It is characterized by itchy, scaly skin plaques. The exact cause of psoriasis is unclear. But mounting evidence implicates the immune ...

Oncology & Cancer

Squamous cell carcinoma can develop on verrucous lesions

(HealthDay)—Squamous cell carcinoma (SCC) can develop on long-standing verrucous lesions, according to a report published as a letter to the editor in the October issue of The Journal of Dermatology.

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Keratinocyte

Keratinocytes are the predominant cell type in the epidermis, the outermost layer of the human skin, constituting 95% of the cells found there. Those keratinocytes found in the basal layer (Stratum germinativum) of the skin are sometimes referred to as "basal cells" or "basal keratinocytes". The primary function of keratinocytes is the formation of a barrier against environmental damage such as pathogens (bacteria, fungi, parasites, viruses), heat, UV radiation and water loss. A number of structural proteins (filaggrin, keratin), enzymes (proteases), lipids and antimicrobial peptides (defensins) contribute to maintain the important barrier function of the skin. Once pathogens start to invade the upper layers of the epidermis, keratinocytes can react with the production of proinflammatory mediators and in particular chemokines such as CXCL10, CCL2 which attract leukocytes to the site of pathogen invasion. Keratinization is part of the physical barrier formation cornification, in which the keratinocytes produce more and more keratin and eventually undergo programmed cell death. The fully cornified keratinocytes that form the outermost layer are constantly shed off and replaced by new cells. The average renewal / turnover time for the epidermis is 21 days.

Keratinocytes form tight junctions with the nerves of the skin and hold the Langerhans cells and intra-dermal lymphocytes in position within the epidermis. Keratinocytes also modulate the immune system: apart from the above mentioned antimicrobial peptides and chemokines they are also potent producers of anti-inflammatory mediators such as IL-10 and TGF-β. When activated, they can stimulate cutaneous inflammation and Langerhans cell activation via TNFα and IL-1β secretion.[citation needed]

Keratinocytes contribute to protecting the body from ultraviolet radiation (UVR) by taking up melanosomes, vesicles containing the endogenous photoprotectant melanin, from epidermal melanocytes. Each melanocyte in the epidermis has several dendrites that stretch out to connect it with many keratinocytes. The melanin is then stored in the keratinocytes' nuclei, where it protects the DNA from UVR-induced damage.

Keratinocytes migrate with a rolling motion during the process of wound healing.

This text uses material from Wikipedia, licensed under CC BY-SA