Role of oxidative stress in the balding dermal papilla
Abstract
The dermal papillae of the hair follicle control its growth, differentiation and
apoptosis via a range of growth factors. These secreted growth factors are known to
differ between those of non-balding scalp and those of balding scalp and can even
differ in response to a common stimuli – androgen. In balding scalp androgen
stimulates the secretion of negative growth factors, while in non-balding scalp
androgen is found to exert little or no effect. Dermal papilla cells (DPCs) can be
cultured in vitro, however those from balding scalp have been found to undergo
premature senescence compared to those from non-balding scalp. A major cause of
premature senescence is oxidative stress – the gradual accumulation of reactive
oxygen species within the cell causing deleterious loss of function. Reactive oxygen
species are known to be mediated in response to androgens and growth factors and
in turn may affect growth factor signalling within the cell. Using low oxygen cell
culture as a means of reducing oxidative stress, balding and non-balding DPCs were
grown and characterised. It was confirmed that low oxygen culture could increase
proliferation, delay senescence and reduce reactive oxygen species with both DPC
types and that balding DPCs showed a higher sensitivity to oxidative stress. It was
also found that secretions of growth factors by the balding DPCs in response to
different oxygen conditions differed greatly to that of the occipital DPCs.
Androgen, but not TGF-β was found to modulate DPC production of catalase, an
antioxidant, under low oxygen conditions and this caused a reduction in reactive
oxygen species in the balding DPCs. Balding DPCs also demonstrated an
upregulation of the antioxidant total glutathione, however had a reduced fraction of
the active reduced form of the molecule. In addition, it was shown for the first time
3
that under cell culture conditions balding DPCs express TGF-β receptors and it was
shown that proliferation and migration of the balding DPCs could be affected by
addition of exogenous TGF-β, highlighting a potential role for TGF-β as an
autocrine growth factor in the balding dermal papilla.
Authors
Upton, JamieCollections
- Theses [4116]