scholarly journals Recent Advances in the Pathogenesis of Autoimmune Hair Loss Disease Alopecia Areata

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Taisuke Ito
Keyword(s):  
Hair Follicle ◽  
Alopecia Areata ◽  
Viral Infections ◽  
Cytotoxic T Cells ◽  
Hair Follicles ◽  
Immune Privilege ◽  
Recent Advances ◽  
Associated Proteins ◽  
A Cell ◽  
Anagen Hair

Alopecia areata is considered to be a cell-mediated autoimmune disease, in which autoreactive cytotoxic T cells recognize melanocyte-associated proteins such as tyrosinase. This review discusses recent advances in the understanding of the pathogenesis of alopecia areata, focusing on immunobiology and hormonal aspects of hair follicles (HFs). The HF is a unique “miniorgan” with its own immune and hormonal microenvironment. The immunosuppressive milieu of the anagen hair bulb modulated by immunosuppressive factors is known as “hair follicle immune privilege.” The collapse of the hair follicle immune privilege leads to autoimmune reactions against hair follicle autoantigens. Alopecia areata is sometimes triggered by viral infections such as influenza that causes excess production of interferons (IFN). IFN-γis one of the key factors that lead to the collapse of immune privilege. This paper reviews the interactions between the endocrine and immune systems and hair follicles in the pathogenesis of alopecia areata.

scholarly journals Gene Expression of Indoleamine 2,3 Dioxygenase 1, Insulin-Growth Factor 1 and Red/IK Cytokine in Alopecia Areata

2014 ◽  
Vol 6 (3) ◽  
pp. 263-266
Author(s):  
Simona Corina ȘENILĂ ◽  
Ovidiu BĂLĂCESCU ◽  
Loredana BĂLĂCESCU ◽  
Elisabeta CANDREA ◽  
Loredana UNGUREANU ◽  
...  
Keyword(s):  
Gene Expression ◽  
Hair Follicle ◽  
Mhc Class I ◽  
Alopecia Areata ◽  
Fas Ligand ◽  
Immune Privilege ◽  
Mrna Levels ◽  
Insulin Growth Factor ◽  
Qrt Pcr ◽  
Anagen Hair

Alopecia areata (AA) is a chronic, T-cell mediated autoimmune disease directed against the hair follicle, which partially evolves due to a loss of the immune privilege of the anagen hair follicle. The immune privilege is maintained by several factors, including a downregulation of MHC class I and II, local immunosupressants and expression of Fas ligand. The purpose of the study was to evaluate several factors involved in the collapse and restoration of the immune privilege. We investigated IDO1, IGF1 and red/IK gene expression in lesional and perilesionalscalp biopsies from alopecia areata patients. Seven paired punch-biopsies were taken from the active edge of alopecic plaque and from the perilesional scalp. Expression of IDO1, IGF1 and red/IK genes was performed by qRT-PCR. In lesional tissue, IGF1, IDO1 and red/IK genes showed an increase in the mRNA levels as compared with the perilesional scalp. By comparing the pairs of data for the investigated genes, IDO1was statistically upregulated in the lesional area. No significant differences were observed between the gene expression in mild or severe AA, from the lesional or perilesional areas. IDO1 mRNA expression was higher in patients with a relapse duration of less than 6 months as compared to patients with a relapse duration of more than 6 months; levels of IGF1 and red/IK mRNA are increased in lesionals compared to perilesional scalp area.

scholarly journals Hair Follicles from Alopecia Areata Patients Exhibit Alterations in Immune Privilege-Associated Gene Expression in Advance of Hair Loss

2010 ◽  
Vol 130 (11) ◽  
pp. 2677-2680 ◽  
Author(s):  
Hoon Kang ◽  
Wen-Yu Wu ◽  
Blanche K.K. Lo ◽  
Mei Yu ◽  
Gigi Leung ◽  
...  
Keyword(s):  
Gene Expression ◽  
Hair Loss ◽  
Alopecia Areata ◽  
Hair Follicles ◽  
Immune Privilege

Human hair growth in vitro

1990 ◽  
Vol 97 (3) ◽  
pp. 463-471
Author(s):  
M.P. Philpott ◽  
M.R. Green ◽  
T. Kealey
Keyword(s):  
Hair Follicle ◽  
Human Hair ◽  
Subcutaneous Fat ◽  
Hair Shaft ◽  
Hair Follicles ◽  
Anagen Hair ◽  
Scalpel Blade ◽  
Thymidine Autoradiography

We report for the first time the successful maintenance and growth of human hair follicles in vitro. Human anagen hair follicles were isolated by microdissection from human scalp skin. Isolation of the hair follicles was achieved by cutting the follicle at the dermo-subcutaneous fat interface using a scalpel blade. Intact hair follicles were then removed from the fat using watchmakers' forceps. Isolated hair follicles maintained free-floating in supplemented Williams E medium in individual wells of 24-well multiwell plates showed a significant increase in length over 4 days. The increase in length was seen to be attributed to the production of a keratinised hair shaft, and was not associated with the loss of hair follicle morphology. [methyl-3H]thymidine autoradiography confirmed that in vitro the in vivo pattern of DNA synthesis was maintained; furthermore, [35S]methionine labelling of keratins showed that their patterns of synthesis did not change with maintenance. The importance of this model to hair follicle biology is further demonstrated by the observations that TGF-beta 1 has a negative growth-regulatory effect on hair follicles in vitro and that EGF mimics the in vivo depilatory effects that have been reported in sheep and mice.

scholarly journals Suppression of FGF5 and FGF18 Expression by Cholesterol-Modified siRNAs Promotes Hair Growth in Mice

2021 ◽  
Vol 12 ◽  
Author(s):  
Jungang Zhao ◽  
Haojie Lin ◽  
Lusheng Wang ◽  
Keke Guo ◽  
Rongrong Jing ◽  
...  
Keyword(s):  
Hair Follicle ◽  
Topical Application ◽  
Inhibitory Effect ◽  
Intradermal Injection ◽  
Hair Follicles ◽  
Anagen Phase ◽  
A Cell ◽  
Hair Follicle Cycle

FGF5 and FGF18 are key factors in the regulation of the hair follicle cycle. FGF5 is overexpressed during the late anagen phase and serves as a crucial regulatory factor that promotes the anagen-to-catagen transition in the hair follicle cycle. FGF18, which is overexpressed during the telogen phase, mainly regulates the hair follicle cycle by maintaining the telogen phase and inhibiting the entry of hair follicles into the anagen phase. The inhibition of FGF5 may prolong the anagen phase, whereas the inhibition of FGF18 may promote the transition of the hair follicles from the telogen phase to the anagen phase. In the present study, we used siRNA to suppress FGF5 or FGF18 expression as a way to inhibit the activity of these genes. Using qPCR, we showed that FGF5-targeting siRNA modified by cholesterol was more effective than the same siRNA bound to a cell-penetrating peptide at suppressing the expression of FGF5 both in vitro and in vivo. We then investigated the effects of the cholesterol-modified siRNA targeting either FGF5 or FGF18 on the hair follicle cycle in a depilated area of the skin on the back of mice. The cholesterol-modified siRNA, delivered by intradermal injection, effectively regulated the hair follicle cycle by inhibiting the expression of FGF5 and FGF18. More specifically, intradermal injection of a cholesterol-modified FGF5-targeted siRNA effectively prolonged the anagen phase of the hair follicles, whereas intradermal injection of the cholesterol-modified FGF18-targeted siRNA led to the mobilization of telogen follicles to enter the anagen phase earlier. The inhibitory effect of the cholesterol-modified FGF18-targeted siRNA on FGF18 expression was also evaluated for a topically applied siRNA. Topical application of a cream containing the cholesterol-modified FGF18-targeted siRNA on a depilated area of the skin of the back of mice revealed comparable inhibition of FGF18 expression with that observed for the same siRNA delivered by intradermal injection. These findings suggested that alopecia could be prevented and hair regrowth could be restored either through the intradermal injection of cholesterol-modified siRNA targeting FGF5 or FGF18 or the topical application of FGF18 siRNA.

scholarly journals Hair follicle immune privilege and its collapse in alopecia areata

2020 ◽  
Vol 29 (8) ◽  
pp. 703-725 ◽  
Author(s):  
Marta Bertolini ◽  
Kevin McElwee ◽  
Amos Gilhar ◽  
Silvia Bulfone‐Paus ◽  
Ralf Paus
Keyword(s):  
Hair Follicle ◽  
Alopecia Areata ◽  
Immune Privilege
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