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PLoS Biology Dec 2017Sixty-five years after Turing first revealed the potential of systems with local activation and long-range inhibition to generate pattern, we have only recently begun to... (Review)
Review
Sixty-five years after Turing first revealed the potential of systems with local activation and long-range inhibition to generate pattern, we have only recently begun to identify the biological elements that operate at many scales to generate periodic patterns in nature. In this Primer, we first review the theoretical framework provided by Turing, Meinhardt, and others that suggests how periodic patterns could self-organize in developing animals. This Primer was developed to provide context for recent studies that reveal how diverse molecular, cellular, and physical mechanisms contribute to the establishment of the periodic pattern of hair or feather buds in the developing skin. From an initial emphasis on trying to disambiguate which specific mechanism plays a primary role in hair or feather bud development, we are beginning to discover that multiple mechanisms may, in at least some contexts, operate together. While the emergence of the diverse mechanisms underlying pattern formation in specific biological contexts probably reflects the contingencies of evolutionary history, an intriguing possibility is that these mechanisms interact and reinforce each other, producing emergent systems that are more robust.
Topics: Animals; Body Patterning; Feathers; Hair; Models, Biological; Signal Transduction; Skin
PubMed: 29261650
DOI: 10.1371/journal.pbio.2004412 -
Biomedicine & Pharmacotherapy =... Jun 2022CXCL12 and its receptors, which are highly expressed in the skin, are associated with various cutaneous diseases, including androgenic alopecia. However, their...
CXCL12 and its receptors, which are highly expressed in the skin, are associated with various cutaneous diseases, including androgenic alopecia. However, their expression and role during the hair cycle are unknown. This study aims to investigate the expression of CXCL12 and its receptor, CXCR4, in the vicinity of hair follicles and their effect on hair growth. CXCL12 was highly expressed in dermal fibroblasts (DFs) and its level was elevated throughout the catagen and telogen phases of the hair cycle. CXCR4 is expressed in the dermal papilla (DP) and outer root sheath (ORS). In hair organ culture, hair loss was induced by recombinant CXCL12 therapy, which delayed the telogen-to-anagen transition and decreased hair length. In contrast, the suppression of CXCL12 using a neutralizing antibody and siRNA triggered the telogen-to-anagen transition and increased hair length in hair organ culture. Neutralization of CXCR7, one of the two receptors for CXCL12, only slightly affected hair growth. However, inhibition of CXCR4, the other receptor for CXCL12, increased hair growth to a considerable extent. In addition, in hair organ culture, the conditioned medium from DFs with CXCL12 siRNA considerably increased the hair length and induced proliferation of DP and ORS cells. CXCL12, through CXCR4 activation, increased STAT3 and STAT5 phosphorylation in DP and ORS cells. In contrast, blocking CXCL12 and CXCR4 decreased the phosphorylation of STAT3 and STAT5. In summary, these findings suggest that CXCL12 inhibits hair growth via the CXCR4/STAT signaling pathway and that CXCL12/CXCR4 pathway inhibitors are a promising treatment option for hair growth.
Topics: Alopecia; Chemokine CXCL12; Hair; Hair Follicle; Humans; RNA, Small Interfering; Receptors, CXCR4; STAT5 Transcription Factor; Signal Transduction
PubMed: 35462338
DOI: 10.1016/j.biopha.2022.112996 -
Acta Dermatovenerologica Alpina,... Jun 2022Uncombable hair syndrome presents with frizzy hair in early childhood. Isolated hair manifestations are usually observed; however, systemic involvement of the nervous...
Uncombable hair syndrome presents with frizzy hair in early childhood. Isolated hair manifestations are usually observed; however, systemic involvement of the nervous system, eyes, and ears have also been reported. The syndrome has been classified into three subtypes, correlating with the three mutated genes: peptidyl arginine deiminase, type III; transglutaminase 3; and trichohyalin. This article presents the clinical picture of uncombable hair syndrome with special attention to its systemic manifestations. It also addresses its molecular aspects. Google Scholar was used to retrieve relevant publications. Clinical and molecular data were tabulated and frequencies were calculated. At least 127 cases were identified. Congenital hair defects were reported in two-thirds of cases, in which hair texture (83%), color (52%), density (15%), and growth (11%) were impaired. Uncombable hair rarely involves the eyebrows and eyelashes, and it may co-occur with loose anagen hair syndrome, androgenic alopecia, alopecia areata, and scarring alopecia. Pathologies of the skin, nails, and teeth were reported among 63%, 28%, and 25%, respectively. Systemic abnormalities were not uncommon. Dysmorphic features (n = 8), and neuropsychiatric/developmental (n = 8), ophthalmic (n = 7), otic (n = 4), and cardiopulmonary (n = 3) manifestations were also reported. Molecular genetic analysis of all patients is recommended to identify genotype-phenotype correlation. A general pediatric review might be needed to rule out any potential systemic association.
Topics: Alopecia Areata; Child; Child, Preschool; Hair; Hair Diseases; Humans; Syndrome
PubMed: 35751533
DOI: No ID Found -
International Journal of Molecular... Nov 2021Sheep () and goats () have, for more than a millennia, been a source of fibres for human use, be it for use in clothing and furnishings, for insulation, for decorative... (Review)
Review
Sheep () and goats () have, for more than a millennia, been a source of fibres for human use, be it for use in clothing and furnishings, for insulation, for decorative and ceremonial purposes, or for combinations thereof. While use of these natural fibres has in some respects been superseded by the use of synthetic and plant-based fibres, increased accounting for the carbon and water footprint of these fibres is creating a re-emergence of interest in fibres derived from sheep and goats. The keratin-associated proteins (KAPs) are structural components of wool and hair fibres, where they form a matrix that cross-links with the keratin intermediate filaments (KIFs), the other main structural component of the fibres. Since the first report of a complete KAP protein sequence in the late 1960s, considerable effort has been made to identify the KAP proteins and their genes in mammals, and to ascertain how these genes and proteins control fibre growth and characteristics. This effort is ongoing, with more and more being understood about the structure and function of the genes. This review consolidates that knowledge and suggests future directions for research to further our understanding.
Topics: Amino Acid Sequence; Animals; Goats; Hair; Humans; Keratins; Sequence Homology, Amino Acid; Sheep; Wool
PubMed: 34884644
DOI: 10.3390/ijms222312838 -
Scientific Reports Oct 2020Necrostatins (Necs) have been developed as a receptor-interacting protein kinase 1 (RIPK1) inhibitor, thus inhibiting necroptosis. In this current study, we have...
Necrostatins (Necs) have been developed as a receptor-interacting protein kinase 1 (RIPK1) inhibitor, thus inhibiting necroptosis. In this current study, we have investigated the possible involvement of necroptosis in the hair cycle regulation and further examined its underlying molecular mechanisms. Diverse RIPK1/3 inhibitors and siRNA were tested in the human outer-root sheath (ORS) cells and animal models. The expression and hair cycle-dependent expression of RIPK 1, respectively, were investigated in the hair follicles (HF) of human, pig, and the mouse. Resulting from the experiment, Nec-1s was most effective in the hair growth promotion among several inhibitors. Nec-1s induced the ORS cell proliferation and migration, and increased the HF length in mouse and pig organ cultures. In addition, it accelerated the telogen-to-anagen transition and elongated the anagen period in the mouse model. Both apoptosis and necroptosis were detected in hair cycle. RIPK1 and RIPK3 were highly expressed in ORS cells during the hair regression period. Nec-1s upregulated the mRNA expression of Wnt3a and Wnt5b, and the activity of β-catenin. Collectively, Nec-1s promotes hair growth through inhibiting necroptosis and activating the Wnt/β-catenin pathway. Necroptosis is involved in hair cycle regression, and Nec-1s is a promising target for hair-loss treatment.
Topics: Animals; Apoptosis; Cell Line; Cell Movement; Cell Proliferation; Hair; Hair Follicle; Humans; Imidazoles; Indoles; Male; Mice; Necroptosis; Swine; Wnt Signaling Pathway
PubMed: 33077863
DOI: 10.1038/s41598-020-74796-1 -
Revue Medicale de Liege Feb 2015Hair is influenced by the effects of the daily environment. Some toxic xenobiotics slow down or block the cell renewal of the hair matrix, thus inhibiting hair growth.... (Review)
Review
Hair is influenced by the effects of the daily environment. Some toxic xenobiotics slow down or block the cell renewal of the hair matrix, thus inhibiting hair growth. The ultraviolet light obviously influences the physical structure and physiology of the hair follicle. Tobacco is similarly responsible for negative influences on the evolution of various alopecias. Several cosmetic procedures for maintaining and making hair more attractive are not always harmless, and they occasionally represent a possible origin for alopecia.
Topics: Alopecia; Environment; Hair; Hair Follicle; Hair Preparations; Humans; Hygiene; Tobacco Use Disorder; Ultraviolet Rays; Xenobiotics
PubMed: 26011990
DOI: No ID Found -
Expert Opinion on Drug Discovery Mar 2015Hair loss or alopecia affects the majority of the population at some time in their life, and increasingly, sufferers are demanding treatment. Three main types of... (Review)
Review
INTRODUCTION
Hair loss or alopecia affects the majority of the population at some time in their life, and increasingly, sufferers are demanding treatment. Three main types of alopecia (androgenic [AGA], areata [AA] and chemotherapy-induced [CIA]) are very different, and have their own laboratory models and separate drug-discovery efforts.
AREAS COVERED
In this article, the authors review the biology of hair, hair follicle (HF) cycling, stem cells and signaling pathways. AGA, due to dihydrotesterone, is treated by 5-α reductase inhibitors, androgen receptor blockers and ATP-sensitive potassium channel-openers. AA, which involves attack by CD8(+)NK group 2D-positive (NKG2D(+)) T cells, is treated with immunosuppressives, biologics and JAK inhibitors. Meanwhile, CIA is treated by apoptosis inhibitors, cytokines and topical immunotherapy.
EXPERT OPINION
The desire to treat alopecia with an easy topical preparation is expected to grow with time, particularly with an increasing aging population. The discovery of epidermal stem cells in the HF has given new life to the search for a cure for baldness. Drug discovery efforts are being increasingly centered on these stem cells, boosting the hair cycle and reversing miniaturization of HF. Better understanding of the molecular mechanisms underlying the immune attack in AA will yield new drugs. New discoveries in HF neogenesis and low-level light therapy will undoubtedly have a role to play.
Topics: Administration, Topical; Alopecia; Animals; Drug Discovery; Hair; Hair Follicle; Humans; Immunotherapy; Pharmaceutical Preparations; Stem Cells
PubMed: 25662177
DOI: 10.1517/17460441.2015.1009892 -
Journal of Optometry 2018The primary role of eyelashes is to protect and maintain the health of the lid margin. However, the mechanisms to fulfill this role are not fully understood. Unraveling... (Review)
Review
The primary role of eyelashes is to protect and maintain the health of the lid margin. However, the mechanisms to fulfill this role are not fully understood. Unraveling these mechanisms will stand to greatly improve the efficiency of eye care professionals' interventions in anomalies of the eyelashes. The aim of this article is to provide a review on eyelashes including highlights and new avenues for research; the biology of both the lash and its follicle; the pathophysiology and management of lash anomalies by eye care professionals; and the effect of iatrogenic factors on lashes. Using the database of Ovid MEDLINE, we reviewed studies specifically directed on human/mammalian eyelashes and key articles on current trends in scalp hair methodologies that can be applicable to lash research. The eyelash morphology, pigmentation and growth rate have been documented using techniques ranging from lash imaging to follicle immunohistochemistry. Furthermore, studies have demonstrated that the lash follicle is sensitive to many factors of the external environment, a variety of systemic/topical medications and cosmetics. Recently, aerodynamic studies using a mammalian eye model confirmed that an optimal lash length was needed so that eyelashes serve a protective role in reducing the number of particles that can reach the eye. Despite recent advances in lash research, studies are still scarce, due to the limited availability of the human lid for sampling. This review brings awareness that further research is needed with respect to eyelashes and will hopefully reduce the gap with scalp hair research.
Topics: Aging; Eyelashes; Eyelid Diseases; Hair Diseases; Hair Follicle; Humans; Iatrogenic Disease
PubMed: 30017866
DOI: 10.1016/j.optom.2018.05.003 -
Environmental Health Perspectives Aug 1974Extensive ambient extraction of several metals from human hair compromises some assumptions concerning the binding of metals to hair and the biochemical process of metal...
Extensive ambient extraction of several metals from human hair compromises some assumptions concerning the binding of metals to hair and the biochemical process of metal incorporation into hair. Hair metal concentrations can reveal metal intoxications and metal deficiencies.The scalp hair selected for investigation included specimens of different colors from both sexes for various donor ages and from different geographic exposure areas. The hair samples were washed by agitation for 30 min with a 1% solution of sodium lauryl sulfate in a pH 7.2 buffer, rinsed repeatedly with deionized water, and oven-dried at 110 degrees C before 2-g portions were taken for extraction and digestion. Extraction involved agitation of the washed hair samples for 21 hr with 40 ml of 1% nitric acid at room temperature (23 degrees C). The extracted hair was digested in order to quantitate the amount of metal that was not extracted. Metal measurements were made by conventional flame atomic absorption spectroscopy. Potential interferences were investigated. Extraction varied between 82 and 100% for Na, Mg, K, Ca, Mn, Zn, Cd, and Pb. Removal of Fe, Ni, and Cu was 33-54%. Anatomical location, binding chemistry, biochemical incorporation, and mass screening are discussed.
Topics: Adolescent; Adult; Binding Sites; Child; Color; Female; Hair; Humans; Male; Metals; Middle Aged; Nitrates; Perchlorates; Scalp; Sodium Dodecyl Sulfate; Spectrophotometry, Atomic; Trace Elements
PubMed: 4377869
DOI: 10.1289/ehp.748191 -
Molecules (Basel, Switzerland) Dec 2021Hair can record chemical information reflecting our living conditions, and, therefore, strands of hair have become a potent analytical target within the biological and... (Review)
Review
Hair can record chemical information reflecting our living conditions, and, therefore, strands of hair have become a potent analytical target within the biological and forensic sciences. While early efforts focused on analyzing complete hair strands in bulk, high spatial resolution mass spectrometry imaging (MSI) has recently come to the forefront of chemical hair-strand analysis. MSI techniques offer a localized analysis, requiring fewer de-contamination procedures per default and making it possible to map the distribution of analytes on and within individual hair strands. Applying the techniques to hair samples has proven particularly useful in investigations quantifying the exposure to, and uptake of, toxins or drugs. Overall, MSI, combined with optimized sample preparation protocols, has improved precision and accuracy for identifying several elemental and molecular species in single strands of hair. Here, we review different sample preparation protocols and use cases with a view to make the methodology more accessible to researchers outside of the field of forensic science. We conclude that-although some challenges remain, including contamination issues and matrix effects-MSI offers unique opportunities for obtaining highly resolved spatial information of several compounds simultaneously across hair surfaces.
Topics: Forensic Sciences; Hair; Humans; Mass Spectrometry
PubMed: 34946604
DOI: 10.3390/molecules26247522