Role of epidermal primary cilia in the homeostasis of skin and hair follicles

2011 ◽  
Vol 124 (9) ◽  
pp. e1-e1
Author(s):  
M. J. Croyle ◽  
J. M. Lehman ◽  
A. K. O'Connor ◽  
S. Y. Wong ◽  
E. B. Malarkey ◽  
...  
Keyword(s):  
Primary Cilia ◽  
Hair Follicles

scholarly journals Role of epidermal primary cilia in the homeostasis of skin and hair follicles

Development ◽  
2011 ◽  
Vol 138 (9) ◽  
pp. 1675-1685 ◽  
Author(s):  
M. J. Croyle ◽  
J. M. Lehman ◽  
A. K. O'Connor ◽  
S. Y. Wong ◽  
E. B. Malarkey ◽  
...  
Keyword(s):  
Primary Cilia ◽  
Hair Follicles

scholarly journals Functional Specificity of the Members of the Sos Family of Ras-GEF Activators: Novel Role of Sos2 in Control of Epidermal Stem Cell Homeostasis

Cancers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 2152
Author(s):  
Fernando C. Baltanás ◽  
Cynthia Mucientes-Valdivieso ◽  
L. Francisco Lorenzo-Martín ◽  
Natalia Fernández-Parejo ◽  
Rósula García-Navas ◽  
...  
Keyword(s):  
Stem Cell ◽  
Layer Structure ◽  
3D Culture ◽  
Hair Follicles ◽  
Specific Cell ◽  
Epidermal Stem Cell ◽  
Primary Keratinocytes ◽  
Cell Homeostasis ◽  
Primary Mouse

Prior reports showed the critical requirement of Sos1 for epithelial carcinogenesis, but the specific functionalities of the homologous Sos1 and Sos2 GEFs in skin homeostasis and tumorigenesis remain unclear. Here, we characterize specific mechanistic roles played by Sos1 or Sos2 in primary mouse keratinocytes (a prevalent skin cell lineage) under different experimental conditions. Functional analyses of actively growing primary keratinocytes of relevant genotypes—WT, Sos1-KO, Sos2-KO, and Sos1/2-DKO—revealed a prevalent role of Sos1 regarding transcriptional regulation and control of RAS activation and mechanistic overlapping of Sos1 and Sos2 regarding cell proliferation and survival, with dominant contribution of Sos1 to the RAS-ERK axis and Sos2 to the RAS-PI3K/AKT axis. Sos1/2-DKO keratinocytes could not grow under 3D culture conditions, but single Sos1-KO and Sos2-KO keratinocytes were able to form pseudoepidermis structures that showed disorganized layer structure, reduced proliferation, and increased apoptosis in comparison with WT 3D cultures. Remarkably, analysis of the skin of both newborn and adult Sos2-KO mice uncovered a significant reduction of the population of stem cells located in hair follicles. These data confirm that Sos1 and Sos2 play specific, cell-autonomous functions in primary keratinocytes and reveal a novel, essential role of Sos2 in control of epidermal stem cell homeostasis.

scholarly journals Localisation and regulation of cholesterol transporters in the human hair follicle: mapping changes across the hair cycle

2021 ◽  
Author(s):  
Megan A. Palmer ◽  
Eleanor Smart ◽  
Iain S. Haslam
Keyword(s):  
Hair Follicle ◽  
Human Hair ◽  
Vital Role ◽  
Transport Proteins ◽  
Hair Follicles ◽  
Regulatory Control ◽  
Cholesterol Transport ◽  
Hair Cycle ◽  
Human Hair Follicle

AbstractCholesterol has long been suspected of influencing hair biology, with dysregulated homeostasis implicated in several disorders of hair growth and cycling. Cholesterol transport proteins play a vital role in the control of cellular cholesterol levels and compartmentalisation. This research aimed to determine the cellular localisation, transport capability and regulatory control of cholesterol transport proteins across the hair cycle. Immunofluorescence microscopy in human hair follicle sections revealed differential expression of ATP-binding cassette (ABC) transporters across the hair cycle. Cholesterol transporter expression (ABCA1, ABCG1, ABCA5 and SCARB1) reduced as hair follicles transitioned from growth to regression. Staining for free cholesterol (filipin) revealed prominent cholesterol striations within the basement membrane of the hair bulb. Liver X receptor agonism demonstrated active regulation of ABCA1 and ABCG1, but not ABCA5 or SCARB1 in human hair follicles and primary keratinocytes. These results demonstrate the capacity of human hair follicles for cholesterol transport and trafficking. Future studies examining the role of cholesterol transport across the hair cycle may shed light on the role of lipid homeostasis in human hair disorders.

scholarly journals Centrin2 regulates CP110 removal in primary cilium formation

2015 ◽  
Vol 208 (6) ◽  
pp. 693-701 ◽  
Author(s):  
Suzanna L. Prosser ◽  
Ciaran G. Morrison
Keyword(s):  
Calcium Binding ◽  
Primary Cilia ◽  
Reverse Genetics ◽  
Cell Types ◽  
Serum Starvation ◽  
Basal Bodies ◽  
Cilium Formation ◽  
Cellular Quiescence ◽  
Retinal Pigmented Epithelial Cells

Primary cilia are antenna-like sensory microtubule structures that extend from basal bodies, plasma membrane–docked mother centrioles. Cellular quiescence potentiates ciliogenesis, but the regulation of basal body formation is not fully understood. We used reverse genetics to test the role of the small calcium-binding protein, centrin2, in ciliogenesis. Primary cilia arise in most cell types but have not been described in lymphocytes. We show here that serum starvation of transformed, cultured B and T cells caused primary ciliogenesis. Efficient ciliogenesis in chicken DT40 B lymphocytes required centrin2. We disrupted CETN2 in human retinal pigmented epithelial cells, and despite having intact centrioles, they were unable to make cilia upon serum starvation, showing abnormal localization of distal appendage proteins and failing to remove the ciliation inhibitor CP110. Knockdown of CP110 rescued ciliation in CETN2-deficient cells. Thus, centrin2 regulates primary ciliogenesis through controlling CP110 levels.

Regulation of hair follicle development by the TNF signal ectodysplasin and its receptor Edar

Development ◽  
2002 ◽  
Vol 129 (10) ◽  
pp. 2541-2553 ◽  
Author(s):  
Johanna Laurikkala ◽  
Johanna Pispa ◽  
Han-Sung Jung ◽  
Pekka Nieminen ◽  
Marja Mikkola ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Hair Follicles ◽  
Wild Type ◽  
Mutant Mouse Embryos ◽  
Anhidrotic Ectodermal Dysplasia ◽  
Embryonic Morphogenesis ◽  
Hair Follicle Development ◽  
And Function ◽  
Insight Into

X-linked and autosomal forms of anhidrotic ectodermal dysplasia syndromes (HED) are characterized by deficient development of several ectodermal organs, including hair, teeth and exocrine glands. The recent cloning of the genes that underlie these syndromes, ectodysplasin (ED1) and the ectodysplasin A receptor (EDAR), and their identification as a novel TNF ligand-receptor pair suggested a role for TNF signaling in embryonic morphogenesis. In the mouse, the genes of the spontaneous mutations Tabby (Ta) and downless (dl) were identified as homologs of ED1 and EDAR, respectively. To gain insight into the function of this signaling pathway in development of skin and hair follicles, we analyzed the expression and regulation of Eda and Edar in wild type as well as Tabby and Lef1 mutant mouse embryos. We show that Eda and Edar expression is confined to the ectoderm and occurs in a pattern that suggests a role of ectodysplasin/Edar signaling in the interactions between the ectodermal compartments and the formation and function of hair placodes. By using skin explant cultures, we further show that this signaling pathway is intimately associated with interactions between the epithelial and mesenchymal tissues. We also find that Ta mutants lack completely the placodes of the first developing tylotrich hairs, and that they do not show patterned expression of placodal genes, including Bmp4, Lef1, Shh, Ptch and Edar, and the genes for β-catenin and activin A. Finally, we identified activin as a mesenchymal signal that stimulates Edar expression and WNT as a signal that induces Eda expression, suggesting a hierarchy of distinct signaling pathways in the development of skin and hair follicles. In conclusion, we suggest that Eda and Edar are associated with the onset of ectodermal patterning and that ectodysplasin/edar signaling also regulates the morphogenesis of hair follicles.

Polaris, a protein disrupted inorpkmutant mice, is required for assembly of renal cilium

2002 ◽  
Vol 282 (3) ◽  
pp. F541-F552 ◽  
Author(s):  
Bradley K. Yoder ◽  
Albert Tousson ◽  
Leigh Millican ◽  
John H. Wu ◽  
Charles E. Bugg ◽  
...  
Keyword(s):  
Primary Cilia ◽  
Collecting Duct ◽  
Physiological Role ◽  
Duct Cell ◽  
Cystic Kidney Disease ◽  
Cystic Kidney ◽  
Apical Surface ◽  
Cystic Disease ◽  
Cortical Collecting Duct

Cilia are organelles that play diverse roles, from fluid movement to sensory reception. Polaris, a protein associated with cystic kidney disease in Tg737°rpkmice, functions in a ciliogenic pathway. Here, we explore the role of polaris in primary cilia on Madin-Darby canine kidney cells. The results indicate that polaris localization and solubility change dramatically during cilia formation. These changes correlate with the formation of basal bodies and large protein rafts at the apical surface of the epithelia. A cortical collecting duct cell line has been derived from mice with a mutation in the Tg737 gene. These cells do not develop normal cilia, which can be corrected by reexpression of the wild-type Tg737 gene. These data suggest that the primary cilia are important for normal renal function and/or development and that the ciliary defect may be a contributing factor to the cystic disease in Tg737°rpkmice. Further characterization of these cells will be important in elucidating the physiological role of renal cilia and in determining their relationship to cystic disease.

scholarly journals The Role of Sonic Hedgehog in Human Holoprosencephaly and Short-Rib Polydactyly Syndromes

2021 ◽  
Vol 22 (18) ◽  
pp. 9854
Author(s):  
Christine Loo ◽  
Michael Pearen ◽  
Grant Ramm
Keyword(s):  
Human Development ◽  
Sonic Hedgehog ◽  
Mammalian Cells ◽  
Animal Studies ◽  
Primary Cilia ◽  
Genetic Mutation ◽  
Wide Variability ◽  
Using Data ◽  
Differentiation And Proliferation

The Hedgehog (HH) signalling pathway is one of the major pathways controlling cell differentiation and proliferation during human development. This pathway is complex, with HH function influenced by inhibitors, promotors, interactions with other signalling pathways, and non-genetic and cellular factors. Many aspects of this pathway are not yet clarified. The main features of Sonic Hedgehog (SHH) signalling are discussed in relation to its function in human development. The possible role of SHH will be considered using examples of holoprosencephaly and short-rib polydactyly (SRP) syndromes. In these syndromes, there is wide variability in phenotype even with the same genetic mutation, so that other factors must influence the outcome. SHH mutations were the first identified genetic causes of holoprosencephaly, but many other genes and environmental factors can cause malformations in the holoprosencephaly spectrum. Many patients with SRP have genetic defects affecting primary cilia, structures found on most mammalian cells which are thought to be necessary for canonical HH signal transduction. Although SHH signalling is affected in both these genetic conditions, there is little overlap in phenotype. Possible explanations will be canvassed, using data from published human and animal studies. Implications for the understanding of SHH signalling in humans will be discussed.

scholarly journals A Model for Primary Cilium Biogenesis by Polarized Epithelial Cells: Role of the Midbody Remnant and Associated Specialized Membranes

2021 ◽  
Vol 8 ◽  
Author(s):  
Leticia Labat-de-Hoz ◽  
Armando Rubio-Ramos ◽  
Javier Casares-Arias ◽  
Miguel Bernabé-Rubio ◽  
Isabel Correas ◽  
...  
Keyword(s):  
Cell Surface ◽  
Primary Cilium ◽  
Primary Cilia ◽  
Control Cell ◽  
Future Research ◽  
Alternative Route ◽  
Ciliary Membrane ◽  
Cilium Formation ◽  
Membrane Compartmentalization

Primary cilia are solitary, microtubule-based protrusions surrounded by a ciliary membrane equipped with selected receptors that orchestrate important signaling pathways that control cell growth, differentiation, development and homeostasis. Depending on the cell type, primary cilium assembly takes place intracellularly or at the cell surface. The intracellular route has been the focus of research on primary cilium biogenesis, whereas the route that occurs at the cell surface, which we call the “alternative” route, has been much less thoroughly characterized. In this review, based on recent experimental evidence, we present a model of primary ciliogenesis by the alternative route in which the remnant of the midbody generated upon cytokinesis acquires compact membranes, that are involved in compartmentalization of biological membranes. The midbody remnant delivers part of those membranes to the centrosome in order to assemble the ciliary membrane, thereby licensing primary cilium formation. The midbody remnant's involvement in primary cilium formation, the regulation of its inheritance by the ESCRT machinery, and the assembly of the ciliary membrane from the membranes originally associated with the remnant are discussed in the context of the literature concerning the ciliary membrane, the emerging roles of the midbody remnant, the regulation of cytokinesis, and the role of membrane compartmentalization. We also present a model of cilium emergence during evolution, and summarize the directions for future research.

Sign in / Sign up

Export Citation Format

Share Document