Anti-aging Flashcards
UV damage to DNA results in
DNA repair/apoptosis
UV damage to keratinocytes results in
epidermal turnover due to cytokine production, growth and migration
Photoaged skin has extensive damage to
dermal connective tissue
UV irradiation induces expression of certain members of ____ family, which ______
MMP (matrix mellanoproteinase)
degrade collagen and other ECM proteins comprising dermal connective tissue
Major structural protein in dermal extracellular matrix
Collagen I
Dermal fibroblasts synthesize
Procollagen
2 primary pathways by which UV irradiation alters dermal collagen
- stimulation of collagen breakdown->fragment, disorganized collagen
- inhibition of procollagen synthesis–>loss of collagen content
Pathways that control procollagen expression
TGF-b
Collagen-degrading enyzmes ____ are produced in _____ and diffuse to _____, and this diffusion may be aided by
MMP-1, 3, 9
epidermis
dermis
direct binding of MMPs to collagenous ECM
Cells respond to excessive UV-induced damage via activation of
transcription factors
NF-Kappa B
AP-1
p53
Direct absorption of UVB photons leads to
- cyclobutane pyrimidine dimers
- pyrimidine (6-4) pyrimidone photoproduct
replication of damaged DNA –> mutations
UVB induced mutations
C->T, CC->TT at dyprimidine sites
UVA is most commonly associated with
oxidative damage
Main mutations of long wave UVA
G->T transversions
presumably arising through mechanisms involving oxidized DNA bases
main DNA product from UVA damage through oxidative mechanism
production of O2 singlet->8-oxo-guanine
