Complex changes in the apoptotic and cell differentiation programs during initiation of the hair follicle response to chemotherapy.

Chemotherapy has severe side effects in normal rapidly proliferating organs, such as hair follicles, and causes massive apoptosis in hair matrix keratinocytes followed by hair loss. To define the molecular signature of hair follicle response to chemotherapy, human scalp hair follicles cultured ex vivo were treated with doxorubicin (DXR), and global microarray analysis was performed 3 hours after treatment. Microarray data revealed changes in expression of 504 genes in DXR-treated hair follicles versus controls.

Bone morphogenetic protein signaling suppresses wound-induced skin repair by inhibiting keratinocyte proliferation and migration.

Bone morphogenetic protein (BMP) signaling plays a key role in the control of skin development and postnatal remodeling by regulating keratinocyte proliferation, differentiation, and apoptosis. To study the role of BMPs in wound-induced epidermal repair, we used transgenic mice overexpressing the BMP downstream component Smad1 under the control of a K14 promoter as an in vivo model, as well as ex vivo and in vitro assays. K14-caSmad1 (transgenic mice overexpressing a constitutively active form of Smad1 under K14 promoter) mice exhibited retarded wound healing associated with significant inhibition of proliferation and increased apoptosis in healing wound epithelium.