Epidermal Stem Cells of the Skin
By raymumme
Abstract
The skin constantly renews itself throughout adult life, and the hair follicle undergoes a perpetual cycle of growth and degeneration. Stem cells (SCs) residing in the epidermis and hair follicle ensure the maintenance of adult skin homeostasis and hair regeneration, but they also participate in the repair of the epidermis after injuries. We summarize here the current knowledge of epidermal SCs of the adult skin. We discuss their fundamental characteristics, the methods recently designed to isolate these cells, the genes preferentially expressed in the multipotent SC niche, and the signaling pathways involved in SC niche formation, SC maintenance, and activation. Finally, we speculate on how the deregulation of these pathways may lead to cancer formation.
Keywords: hair follicle, multipotency, self-renewal, cell fate determination, Wnt signaling, Bmp, cancer
Skin and its appendages ensure a number of critical functions necessary for animal survival. Skin protects animals from water loss, temperature change, radiation, trauma, and infections, and it allows animals to perceive their environment through tactile sense. Through camouflage, the skin provides protection against predators, and it also serves as decoration for social and reproductive behavior.
Adult skin is composed of a diverse organized array of cells emanating from different embryonic origins. In mammals, shortly after gastrulation, the neurectoderm cells that remain at the embryo surface become the epidermis, which begins as a single layer of unspecified progenitor cells. During development, this layer of cells forms a stratified epidermis (sometimes called interfollicular epidermis), the hair follicles (HRs), sebaceous glands, and, in nonhaired skin, the apocrine (sweat) glands. Mesoderm-derived cells contribute to the collagen-secreting fibroblasts of the underlying dermis, the dermovasculature that supplies nutrients to skin, arrector pili muscles that attach to each hair follicle (HF), the subcutaneous fat cells, and the immune cells that infiltrate and reside in the skin. Neural crestderived cells contribute to melanocytes, sensory nerve endings of the skin, and the dermis of the head. Overall, approximately 20 different cell types reside within the skin.
In the adult, many different types of stem cells (SCs) function to replenish these various cell types in skin as it undergoes normal homeostasis or wound repair. Some SCs (e.g., those that replenish lymphocytes) reside elsewhere in the body. Others (e.g., melanoblasts and epidermal SCs) reside within the skin itself. This review concentrates primarily on epidermal SCs, which possess two essential features common to all SCs: They are able to self-renew for extended periods of time, and they differentiate into multiple lineages derived from their tissue origin (Weissman et al. 2001).
Mature epidermis is a stratified squamous epithelium whose outermost layer is the skin surface. Only the innermost (basal) layer is mitotically active. The basal layer produces, secretes, and assembles an extracellular matrix (ECM), which constitutes much of the underlying basement membrane that separates the epidermis from the dermis. The most prominent basal ECM is laminin5, which utilizes 31-integrin for its assembly. As cells leave the basal layer and move outward toward the skin surface, they withdraw from the cell cycle, switch off integrin and laminin expression, and execute a terminal differentiation program. In the early stages of producing spinous and granular layers, the program remains transcriptionally active. However, it culminates in the production of dead flattened cells of the cornified layer (squames) that are sloughed from the skin surface, continually being replaced by inner cells moving outward ().
Epidermal development and hair follicle morphogenesis. The surface of the early embryo is covered by a single layer of ectodermal cells that adheres to an underlying basement membrane of extracellular matrix. As development proceeds, the epidermis progressively ...
The major structural proteins of the epidermis are keratins, which assemble as obligate heterodimers into a network of 10-nm keratin intermediate filaments (IFs) that connect to 64-integrin-containing hemidesmosomes that anchor the base of the epidermis to the laminin5-rich, assembled ECM. Keratin IFs also connect to intercellular junctions called desmosomes, composed of a core of desmosomal cadherins. Together, these connections to keratin IFs provide an extensive mechanical framework to the epithelium (reviewed in Omary et al. 2004). The basal layer is typified by the expression of keratins K5 and K14 (also K15 in the embryo), whereas the intermediate suprabasal (spinous) layers express K1 and K10. Desmosomes connected to K1/K10 IFs are especially abundant in suprabasal cells, whereas basal cells possess a less robust network of desmosomes and K5/K14. Rather, basal cells utilize a more dynamic cytoskeletal network of microtubules and actin filaments that interface through -and -catenins to E-cadherin-mediated cell-cell (adherens) junctions, in addition to the 1-integrin-mediated cell-ECM junctions (reviewed in Green et al. 2005, Perez-Moreno et al. 2003). Filaggrin and loricrin are produced in the granular layer. The cornified envelope seals the epidermal squames and provides the barrier that keeps microbes out and essential fluids in (Candi et al. 2005, Fuchs 1995) (). The program of terminal differentiation in the epidermis is governed by a number of transcription factor families, including AP2, AP1, C/EBPs, Klfs, PPARs, and Notch (reviewed in Dai & Segre 2004).
Although the molecular mechanisms underlying the process of epidermal stratification are still unfolding, several studies have recently provided clues as to how this might happen. Increasing evidence suggests the transcription factor p63 might be involved. Mice null for the gene encoding p63 present an early block in the program of epidermal stratification (Mills et al. 1999, Yang et al. 1999).
Continue reading here:
Epidermal Stem Cells of the Skin
- Jessner's Lymphocytic Infiltration of the Skin Mimicking Rosacea: A Rare Case Presentation - Dermatology Times - April 28th, 2024
- Device improves stem cell generation and chance for accessible Alzheimer's cell therapy | KTH Royal Institute of ... - TT Nyhetsbyrn - April 28th, 2024
- Colossal Creates Elephant Stem Cells for the First Time in Quest to Revive the Woolly Mammoth - Singularity Hub - March 18th, 2024
- Vitamin A could have a key role in both stem cell biology and wound healing: Study - Medical Dialogues - March 10th, 2024
- A dive into the genetic history of India, and the role of vitamin A in skin repair - Science - March 10th, 2024
- Herbosa: Clinic under probe after skin treatments linked to womans death - Philstar.com - January 22nd, 2024
- These Will Be the Biggest Skin-Care Trends of 2024 - Allure - December 28th, 2023
- Sorry, But These 10 Skincare Products Are A Scam - Refinery29 - December 12th, 2023
- Cyclerion Strengthens Board of Directors with Experienced Company Builder and Cutting-edge Innovator - December 4th, 2023
- Aptose Appoints Fletcher Payne Chief Business Officer, Expanding his Executive Role - December 4th, 2023
- Opthea to Present at the FLORetina 2023 Congress - December 4th, 2023
- HUTCHMED Highlights Clinical Data to be Presented at 2023 ESMO Asia and ESMO Immuno-Oncology Congresses - December 4th, 2023
- AC Immune Strengthens Management, Appoints Madiha Derouazi as CSO and Christopher Roberts as CFO - December 4th, 2023
- Publication of a transparency notification received from Tolefi SA (Article 14 §1 of the Law of 2 May 2007) - December 4th, 2023
- Annovis Bio Appoints Andrew Walsh as Vice President Finance - December 4th, 2023
- Foghorn Therapeutics Announces Clinical Data from Phase 1 Study of FHD-286, a Novel BRG1/BRM Inhibitor, in Patients with Advanced Hematologic... - December 4th, 2023
- Akari Therapeutics Appoints Experienced Life Sciences Entrepreneur Samir R. Patel, M.D. to Board of Directors - December 4th, 2023
- Ovid Therapeutics to Present Five Abstracts Supporting its Epilepsy Programs at the 77th American Epilepsy Society Annual Meeting (2023) - December 4th, 2023
- Spectral Medical Announces CFO Departure - December 4th, 2023
- Are STEM CELL EXOSOMES the secret to a 'snatched' jawline? Discover the products that influencers are claiming - Daily Mail - November 18th, 2023
- Defence Mechanisms: Four ways your body is protecting you every time you fall sick - indulgexpress - May 16th, 2023
- Treat Yourself to a Spa Day With a $100 Deal on $600 Worth of Products From Elemis, 111SKIN, Nest & More - E! NEWS - May 16th, 2023
- INTERNATIONAL STEM CELL CORP MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS (form 10-K) - Marketscreener.com - April 5th, 2023
- Skin Regeneration: The Science and How to Boost It - Healthline - March 9th, 2023
- Treat Yourself to a Spa Day With a $100 Deal on $600 Worth of Products From Elemis, U Beauty, Nest & More - E! NEWS - March 1st, 2023
- 7-year-old vows to find a cure for brother in need of bone marrow transplant - WJLA - February 21st, 2023
- World's most radioactive man 'cried blood' as his skin melted in 83-day nightmare - Times Now - February 4th, 2023
- How old are you, really? The answer is written on your face. - National Geographic UK - February 4th, 2023
- Skin: Layers, Structure and Function - Cleveland Clinic - January 27th, 2023
- Human skin | Definition, Layers, Types, & Facts | Britannica - January 27th, 2023
- Skin Disorders: Pictures, Causes, Symptoms, and Treatment - Healthline - January 27th, 2023
- Skin care: 5 tips for healthy skin - Mayo Clinic - January 27th, 2023
- Skin Care and Aging | National Institute on Aging - January 27th, 2023
- Wrinkles - Symptoms and causes - Mayo Clinic - January 27th, 2023
- Dry skin - Symptoms and causes - Mayo Clinic - January 27th, 2023
- Stem cells: a brief history and outlook - Science in the News - January 3rd, 2023
- Still Drinking Green Tea? Doctor Reveals A Healthier Drink With Proven Benefits For Diabetes, Aging, Oxidative Stress, And Cancer - Revyuh - January 3rd, 2023
- RUDN Physician And Russian Scientists Investigate Long-term Effects Of Treating Diabetic Ulcers With Stem Cells - India Education Diary - December 25th, 2022
- The Use of Stem Cells in Burn Wound Healing: A Review - Hindawi - December 1st, 2022
- FACTORFIVE Skincare The Power of Stem Cells for Skin - December 1st, 2022
- Embryonic Stem Cells - The Definitive Guide | Biology Dictionary - December 1st, 2022
- From pro soccer hopeful to hip hop artist with illness and addiction along the way, Tymaz Bagbani releases debut album - Toronto Star - December 1st, 2022
- Stem Cells | The ALS Association - November 22nd, 2022
- What is a stem cell? YourGenome - October 29th, 2022
- Skin Cell - The Definitive Guide | Biology Dictionary - October 29th, 2022
- Explora Journeys Plans Extensive Fitness And Well-Being Initiatives At Sea, Right On Trend - Forbes - October 29th, 2022
- Ahead of the holiday shopping season, Amazon kicks off second annual Holiday Beauty Haul on Oct. 24 - KXAN.com - October 21st, 2022
- Human skin color - Wikipedia - October 13th, 2022
- Mesenchymal Stem Cells | Properties, Process, Functions, & Therapies - October 13th, 2022
- Skin Grafting, Cryopreservation, and Diseases: A Review Article - Cureus - October 13th, 2022
- Anti-ageing cosmetics: Can they turn back the hands of the clock? - The Sunday Guardian Live - The Sunday Guardian - October 13th, 2022
- Brennand named Elizabeth Mears and House Jameson Professor of Psychiatry - Yale News - October 13th, 2022
- The Switch to Regenerative Medicine - Dermatology Times - October 13th, 2022
- Last Chance to Get The Collagen-Infused Massage Oil That Moisturizes Skin & Diminishes Cellulite For Less Than $20 - msnNOW - October 13th, 2022
- Addison's Disease Explained: Causes, Symptoms, And Treatments - Health Digest - October 13th, 2022
- Stem Cells Therapy for Autism: Does it Work? - October 5th, 2022
- Stem-like CD8 T cells mediate response of adoptive cell ... - PubMed - October 5th, 2022
- 6 Under Eye Products You Need To Have STAT - Grazia India - October 5th, 2022
- CellResearch Corporation (CRC) to present promising new stem cell products for the treatment of chronic diabetic foot ulcers at the world's premier... - September 27th, 2022
- Reprogramming pig cells leads way for new regenerative therapies - National Hog Farmer - September 27th, 2022
- A glimpse into Indian consumers expectations for cosmetic treatments and consumption insights - The Financial Express - September 27th, 2022
- Tajmeel redefines beauty to give its patients the best results - Gulf News - September 27th, 2022
- Here Is Why You Heal Slower As You Age - Health Digest - September 27th, 2022
- Creating stem cells from minipigs offers promise for improved treatments - University of Wisconsin-Madison - September 19th, 2022
- Israeli Biotech Firm Plans to Create Human Embryos to Harvest Organs, Field Experts Say There are Ethical Concerns - CBN.com - September 19th, 2022
- CellResearch Corporation (CRC) announces positive results of Phase I study for CorLiCyte - PR Newswire - September 19th, 2022
- The best CBD and hemp products for pampering your skin this fall - Leafly - September 19th, 2022
- Benjamin Button For Real? Scientists Are Close To Cracking The Code To Reverse Aging - Worldcrunch - September 19th, 2022
- I took an international trip with my frozen eggs to learn about the fertility industry - MIT Technology Review - September 19th, 2022
- Propanc Biopharma Reports Significant Effects of PRP Against the Tumor Microenvironment - Business Wire - September 11th, 2022
- 6 Ingredients to Avoid Putting on Your Skin - Healthline - September 3rd, 2022
- Regenerative Properties of the Newborn Heart Offers Hope for Those With Congenital Heart Disease - The Epoch Times - September 3rd, 2022
- Meet White Orange: The Vitamin C Skin Care Brand For Sensitive Skin - Bustle - September 3rd, 2022
- Rejuvenation Roundup August 2022 - Lifespan.io News - September 3rd, 2022
- To better understand Parkinson's disease, this San Diego expert sent her own cells to space - The San Diego Union-Tribune - August 26th, 2022
- Inside the race to make human sex cells in the lab - MIT Technology Review - August 26th, 2022
- Global Biomaterials Market to Reach Value of $372.7 Billion by 2028 | Demand For Biomaterials in the Healthcare Industry will Grow by 53% Over the... - August 26th, 2022
- A Groovy Guide to Anti-Aging Products With CBD and Mushrooms - Out Magazine - August 26th, 2022
- New milestone organoid synthesis will boost disease and drug development research - RegMedNet - August 10th, 2022
- Victoria Beckham and Kim Kardashian are fans of Augustinus Baders skincare range - and you can get 20% off - The Mirror - August 10th, 2022