Bone morphogenetic proteins differentially regulate pigmentation in human skin cells
Bone Morphogenetic Protein 4; Antagonists & inhibitors; Metabolism; Pharmacology
Bone Morphogenetic Protein 6; Antagonists & inhibitors; Metabolism; Pharmacology
Bone Morphogenetic Protein Receptors
Epidermis; Drug effects; Radiation effects
Gene knockdown techniques
p38 Mitogen-Activated Protein Kinases
MetadataShow full item record
AbstractBone morphogenetic proteins (BMPs) are a large family of multi-functional secreted signalling molecules. Previously BMP2/4 were shown to inhibit skin pigmentation by downregulating tyrosinase expression and activity in epidermal melanocytes. However, a possible role for other BMP family members and their antagonists in melanogenesis has not yet been explored. In this study we show that BMP4 and BMP6, from two different BMP subclasses, and their antagonists noggin and sclerostin were variably expressed in melanocytes and keratinocytes in human skin. We further examined their involvement in melanogenesis and melanin transfer using fully matched primary cultures of adult human melanocytes and keratinocytes. BMP6 markedly stimulated melanogenesis by upregulating tyrosinase expression and activity, and also stimulated the formation of filopodia and Myosin-X expression in melanocytes, which was associated with increased melanosome transfer from melanocytes to keratinocytes. BMP4, by contrast, inhibited melanin synthesis and transfer to below baseline levels. These findings were confirmed using siRNA knockdown of BMP receptors BMPR1A/1B or of Myosin-X, as well as by incubating cells with the antagonists noggin and sclerostin. While BMP6 was found to use the p38MAPK pathway to regulate melanogenesis in human melanocytes independently of the Smad pathway, p38MAPK, PI3-K and Smad pathways were all involved in BMP6-mediated melanin transfer. This suggests that pigment formation may be regulated independently of pigment transfer. These data reveal a complex involvement of regulation of different members of the BMP family, their antagonists and inhibitory Smads, in melanocytes behaviour.
CitationSingh, S. K., Abbas, W. A., Tobin, D. J. (2012) Bone morphogenetic proteins differentially regulate pigmentation in human skin cells. Journal of Cell Science, 125 (Pt 18), 4306-19.
Link to publisher’s versionhttp://dx.doi.org/10.1242/jcs.102038
Showing items related by title, author, creator and subject.
Enhanced DNA binding capacity on up-regulated epidermal wild-type p53 in vitiligo by H2O2-mediated oxidation: a possible repair mechanism for DNA damageSalem, Mohamed M.A.; Shalbaf, Mohammad; Gibbons, Nick C.; Chavan, Bhavan; Thornton, M. Julie; Schallreuter, Karin U. (2009)Vitiligo is characterized by a patchy loss of inherited skin color affecting approximately 0.5% of individuals of all races. Despite the absence of the protecting pigment and the overwhelming evidence for hydrogen peroxide (H(2)O(2))-induced oxidative stress in the entire epidermis of these patients, there is neither increased photodamage/skin aging nor a higher incidence for sun-induced nonmelanoma skin cancer. Here we demonstrate for the first time increased DNA damage via 8-oxoguanine in the skin and plasma in association with epidermal up-regulated phosphorylated/acetylated p53 and high levels of the p53 antagonist p76(MDM2). Short-patch base-excision repair via hOgg1, APE1, and polymerasebeta DNA repair is up-regulated. Overexpression of Bcl-2 and low caspase 3 and cytochrome c levels argue against increased apoptosis in this disease. Moreover, we show the presence of high epidermal peroxynitrite (ONOO(-)) levels via nitrotyrosine together with high nitrated p53 levels. We demonstrate by EMSA that nitration of p53 by ONOO(-) (300 x 10(-6) M) abrogates DNA binding, while H(2)O(2)-oxidized p53 (10(-3) M) enhances DNA binding capacity and prevents ONOO(-)-induced abrogation of DNA binding. Taken together, we add a novel reactive oxygen species to the list of oxidative stress inducers in vitiligo. Moreover, we propose up-regulated wild-type p53 together with p76(MDM2) as major players in the control of DNA damage/repair and prevention of photodamage and nonmelanoma skin cancer in vitiligo.
Bone morphogenetic protein antagonist noggin promotes skin tumorigenesis via stimulation of the Wnt and Shh signaling pathwaysSharov, A.A.; Mardaryev, Andrei N.; Sharova, T.Y.; Grachtchouk, M.; Atoyan, R.; Byers, H.R.; Seykora, J.T.; Overbeek, P.; Dlugosz, A.; Botchkarev, Vladimir A. (2009)Bone morphogenetic proteins (BMPs) play pivotal roles in the regulation of skin development. To study the role of BMPs in skin tumorigenesis, BMP antagonist noggin was used to generate keratin 14-targeted transgenic mice. In contrast to wild-type mice, transgenic mice developed spontaneous hair follicle-derived tumors, which resemble human trichofolliculoma. Global gene expression profiles revealed that in contrast to anagen hair follicles of wild-type mice, tumors of transgenic mice showed stage-dependent increases in the expression of genes encoding the selected components of Wnt and Shh pathways. Specifically, expression of the Wnt ligands increased at the initiation stage of tumor formation, whereas expression of the Wnt antagonist and tumor suppressor Wnt inhibitory factor-1 decreased, as compared with fully developed tumors. In contrast, expression of the components of Shh pathway increased in fully developed tumors, as compared with the tumor placodes. Consistent with the expression data, pharmacological treatment of transgenic mice with Wnt and Shh antagonists resulted in the stage-dependent inhibition of tumor initiation, and progression, respectively. Furthermore, BMP signaling stimulated Wnt inhibitory factor-1 expression and promoter activity in cultured tumor cells and HaCaT keratinocytes, as well as inhibited Shh expression, as compared with the corresponding controls. Thus, tumor suppressor activity of the BMPs in skin epithelium depends on the local concentrations of noggin and is mediated at least in part via stage-dependent antagonizing of Wnt and Shh signaling pathways.
MSK1 regulates homeostatic and experience-dependent synaptic plasticityCorrêa, Sonia A.L.; Hunter, C.J.; Palygin, O.; Wauters, S.C.; Martin, K.J.; McKenzie, C.; McKelvey, K.; Morris, R.G.; Pankratov, Y.; Arthur, J.S.; et al. (2012)The ability of neurons to modulate synaptic strength underpins synaptic plasticity, learning and memory, and adaptation to sensory experience. Despite the importance of synaptic adaptation in directing, reinforcing, and revising the behavioral response to environmental influences, the cellular and molecular mechanisms underlying synaptic adaptation are far from clear. Brain-derived neurotrophic factor (BDNF) is a prime initiator of structural and functional synaptic adaptation. However, the signaling cascade activated by BDNF to initiate these adaptive changes has not been elucidated. We have previously shown that BDNF activates mitogen- and stress-activated kinase 1 (MSK1), which regulates gene transcription via the phosphorylation of both CREB and histone H3. Using mice with a kinase-dead knock-in mutation of MSK1, we now show that MSK1 is necessary for the upregulation of synaptic strength in response to environmental enrichment in vivo. Furthermore, neurons from MSK1 kinase-dead mice failed to show scaling of synaptic transmission in response to activity deprivation in vitro, a deficit that could be rescued by reintroduction of wild-type MSK1. We also show that MSK1 forms part of a BDNF- and MAPK-dependent signaling cascade required for homeostatic synaptic scaling, which likely resides in the ability of MSK1 to regulate cell surface GluA1 expression via the induction of Arc/Arg3.1. These results demonstrate that MSK1 is an integral part of a signaling pathway that underlies the adaptive response to synaptic and environmental experience. MSK1 may thus act as a key homeostat in the activity- and experience-dependent regulation of synaptic strength.