Hierarchical Classification And Transcriptome Analysis Of Variable Hair Miniaturization In Androgenetic Alopecia

BackgroundAndrogenetic alopecia is the most common type of hair loss diseases among male population.It would do harm to the mental health of the patients,especially for the youngsters.AGA features hair miniaturization which starts from the frontotemporal area through the "M" shape to form the final "U" shape.However,the variations of hair miniaturization during the development of AGA have not been studied wellObjective1.To hierarchically classify variable miniaturized hair follicles2.To evaluate the differences between upper part and lower part of variable miniaturized hair follicles3.To explore the transcriptional profile of variable miniaturized hair follicles MethodsMethods1.To hierarchically classify variable miniaturized hair folliclesThe hair diameter in the balding area and non-balding area of AGA patients was measured,compared with normal people.Hair cycle and length of the variable miniaturized hair follicles were assessed.Structures of hair follicles were evaluated through H&E staining2.to evaluate the differences between upper part and lower part of variable miniaturized hair folliclesProliferative epithelial was evaluated in the variable miniaturized hair follicles through immunostaining.Then followed the distribution of hair follicle stem cells and progenitors.Expression of pathological molecules were assessed in the upper portion and lower portion of variable miniaturized hair follicles through Q-PCR3.to explore the transcriptional profile of variable miniaturized hair folliclesRNA-sequencing was conducted to the upper portion and lower portion of variable miniaturized hair follicles.Then,bioinformatic analysis was performed to the differential expressed genes based on the pubmed database and GO database.Results1.to hierarchically classify variable miniaturized hair folliclesAccording to the hair diameter analysis,variable miniaturized hair follicle could be classified as early miniaturized hair follicle(EMHF),mediate miniaturized hair follicle(MMHF),advanced miniaturized hair follicle(AMHF)and occipital control hair follicle(OCHF)2.to evaluate the differences between upper part and lower part of variable miniaturized hair folliclesThe upper portion is different from the lower portion in many aspects.Firstly,the proliferative epithelial was located in the lower portion instead of the upper portion Secondly,the hair follicle stem cells which remained throughout miniaturization were distributed in the upper portion and the progenitors which vanished gradually during miniaturization in the lower portion.Thirdly,the pathological molecules such as AR and PTGDS were upregulated stepwise in the lower portion of variable miniaturized hair follicles other than in the upper portion.3.to explore the transcriptional profile of variable miniaturized hair folliclesCompared with OCHF,inflammatory infiltration was observed in the upper portion of EMHF and MMHF.For the AMHF,inflammatory infiltration and disruption of stem cell homeostasis were observed in the upper portion,and growth inhibition,apoptosis,inflammation,disturbed differentiation and pigmentation were observed in the lower portion.Lipid metabolism and epithelialization were observed in the lower portion of all variable miniaturized hair follicle.ConclusionIn the development AGA,there exists variations in the miniaturization of hair follicle which could be assessed by the hair diameter.What's more,the upper portion is distinct from the lower portion during miniaturization.Inflammation,disruption of stem cell homeostasis,hair differentiation and pigmentation,lipid metabolism and epithelialization may play important roles in the variable miniaturization.According to the current research,miniaturization could be assessed by analysis of hair diameter.What's more,new medications could be developed to target the exact molecules.