Ultraviolet radiation effects on skin cell and immune system

Producción CyT

Capítulo de Libro

Autoría

PAZ, MARIELA LAURA

Fecha

2014

Editorial y Lugar de Edición

Nova Science Publishers

Libro

UV Radiation: Applications, Effects and Properties (pp. 145-182)
Nova Science Publishers

ISBN

978-1-63321-090-5

Resumen Información suministrada por el agente en SIGEVA

Human skin is constantly challenged by environmental stimuli, like microorganisms, chemicals and sunlight-contained ultraviolet radiation (UVr). Skin is composed of a stratified epithelium -epidermis- and the underlying connective and adipose tissue -dermis and hypodermis respectively-. There are several structures contained in the dermis like blood and lymphatic vessels, sebaceous and sweat glands, hair follicles and sensitive nerve terminals. Among the different cells belonging to this import... Human skin is constantly challenged by environmental stimuli, like microorganisms, chemicals and sunlight-contained ultraviolet radiation (UVr). Skin is composed of a stratified epithelium -epidermis- and the underlying connective and adipose tissue -dermis and hypodermis respectively-. There are several structures contained in the dermis like blood and lymphatic vessels, sebaceous and sweat glands, hair follicles and sensitive nerve terminals. Among the different cells belonging to this important tissue, keratinocytes are the main epidermal cell type (almost 95% of all epidermal cells). As a consequence, these cells are more frequently exposed to the harmful effects of UVr (especially those induced by UVB), since this radiation has a low penetration capacity. UVr affects keratinocytes producing direct DNA damage (leading to cell cycle arrest and apoptosis) and also alterations in the cellular metabolism, including mitochondrial dysfunction. However, direct cellular alterations are not the unique harmful effect produced on keratinocytes. These cells are capable of producing large quantities of different cytokines, growth factors and lipid-derived inflammatory mediators in response to UVr exposure, leading to both local inflammation and systemic immunosuppression. Taken together, all of these effects can induce abnormal transformation of epidermal cells. Malignant transformed keratinocytes lead to the development of the most common kind of human tumor: non-melanoma skin cancer (being basal cell carcinoma -BCC- and squamous cell carcinoma -SCC- the more frequent types). Cutaneous photosensitivity (CP) is a condition where a skin abnormal reaction to UVr takes place. The mechanisms involved in CP development are mostly related to autoimmunity and there has been great controversy about whether anti-nuclear antibodies produce photosensitive skin lesions, specially anti-Ro/SS-A autoantibodies. In our laboratory, during the last decade, we have been studying UVr effects on the skin and immune system using two different models: a human keratinocyte cell line (HaCaT cells) and a immunocompetitive hairless mice strain (SKH:1). Using these models we have investigated cellular alterations, mitochondrial dysfunction and acute vs chronic inflammation, as well as SCC development and treatment. Treatment strategies included a non-steroidal anti-inflammatory drug, naproxen, and a probiotic-isolated molecule, lipoteichoic acid from Lactobacillus rhamnosus. We have also studied anti-Ro/SS-A autoantibodies in both models, and their relationship with CP.

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Palabras Clave

INFLAMMATIONKERATINOCYTESSQUAMOUS CELL CARCINOMAOXIDATIVE STRESS