UV Radiation and DNA Repair Flashcards
Describe the role of UV radiation effects on the skin
- Damage to RNA, DNA, lipids, proteins
- Pro-inflammatory
- Immunosuppressive
- Innate defense induction
- Apoptosis induction
- Vitamin D synthesis
Describe vitamin D metabolism in the skin
- UVR => non-enzymatic synthesis of cholecalciferol (VitD3) and ergocalciferol (VitD2)
- VitD2&3 converted to active form in liver and kidney (di-hydroxyVitD3)
Also have dietary supplements that contain VitD3 and VitD2
Define SPF
Sun Protective Factor for UVB
- Most sunscreens don’t include UVA protection
What does it mean to increase or decrease SPF?
Increase/decrease of UVB protection
What is the rationale for sunscreen agent use?
Protection against sunburn, DNA damage
What are the composition and effects of solar radiation?
a
Which types of UV radiation causes sunburn?
UVB
Which types of UV radiation causes photoaging?
UVA
Which types of UV radiation causes corneal burns?
UVB
What are the skin’s defense against UV radiation?
- Apoptosis of cells w/DNA damage
- DNA repair
- Defenses against ROS
- Melanin
What is the function of a melanocyte?
Produce melanosomes (filled w/ melanin)
Deposit melanin into keratinocytes
What is the function of melanogenesis?
Process of producing melanin in melanosomes
Albino = lack tyrosinase (can’t produce melanin)
What is the function of melanin?
- Absorb UVB radiation
- Block UVB passing through skin layers
Persons w/ darker skin are better protected against UVB
Which types of skin diseases are caused by UV radiation?
- Basal/squamous cell carcinomas, melanomas
- Solar urticaria (hives b/c of UVR)
- Xeroderma pigmentosum (DNA repair defect)
- Psoriasis, lupus (exacerbated by UVR)
