Cheng Yi, Gao Yang, Zhao Lu, Gao Shunqiang, Zhang Guoqiang, Zhang Yan
Department of Dermatology, the Fourth Hospital of Hebei Medical University, Shi Jiazhuang, Hebei Province, China.
Department of Interventional Radiology, Hebei Children's Hospital, Shi Jiazhuang, Hebei Province, China.
Rev Assoc Med Bras (1992). 2017 Oct;63(10):883-889. doi: 10.1590/1806-9282.63.10.883.
Dermal papilla cells (DPCs) are located in the hair follicles and play an important role in hair growth. These cells have the ability to induce hair follicle formation when they display aggregative behavior. DPCs derived from the androgenetic alopecia (AGA) area undergo premature senescence in vitro, associated with p16INK4a expression. The aim of the current study was to investigate the expression of p16INK4a in aggregative and non-aggregative DPCs and the effect of p16INK4a down-regulation in these cells by adenovirus-mediated RNA interference (RNAi).
DPCs were isolated and cultured from healthy human scalp. p16INK4a gene and protein were detected in aggregative and non-aggregative cells. Expression of p16INK4a in DPCs was silenced by infection with rAd5-CDKN1A-1p2shRNA. Cell fate was monitored after infection. The growth of cells was measured by MTT assay. Cell cycle was evaluated by flow cytometry (FCM).
DPCs were isolated by digestion and showed aggregative behavior for six passages. The expression of p16INK4a showed a clear upward trend in non-aggregative cells when compared with aggregative group. p16INK4a expression was silenced by rAd5-CDKN1A-1p2shRNA (p<0.05). The p16INK4a-silenced cells grew more rapidly and exhibited a trend towards aggregative growth. There was an increase in the proportion of cells in G1 phase, while those in S phase were reduced after p16INK4a gene silencing (p<0.05).
Our results suggest that p16INK4a plays an important role in the premature senescence and aggregative behavior of DPCs. These observations can lead to novel therapeutic strategies for treatment of AGA.
真皮乳头细胞（DPCs）位于毛囊中，在头发生长中起重要作用。当这些细胞表现出聚集行为时，它们具有诱导毛囊形成的能力。源自雄激素性脱发（AGA）区域的DPCs在体外会过早衰老，这与p16INK4a的表达有关。本研究的目的是调查p16INK4a在聚集型和非聚集型DPCs中的表达情况，以及通过腺病毒介导的RNA干扰（RNAi）下调这些细胞中p16INK4a的作用。
从健康人头皮中分离并培养DPCs。检测聚集型和非聚集型细胞中p16INK4a基因和蛋白的表达。用rAd5-CDKN1A-1p2shRNA感染使DPCs中p16INK4a的表达沉默。感染后监测细胞命运。通过MTT法测量细胞生长情况。通过流式细胞术（FCM）评估细胞周期。
通过消化分离出DPCs，并在传代6次时表现出聚集行为。与聚集组相比，非聚集型细胞中p16INK4a的表达呈明显上升趋势。rAd5-CDKN1A-1p2shRNA使p16INK4a的表达沉默（p<0.05）。p16INK4a沉默的细胞生长更快，并呈现出聚集生长的趋势。p16INK4a基因沉默后，G1期细胞比例增加，而S期细胞比例减少（p<0.05）。
我们的数据表明，p16INK4a在DPCs的过早衰老和聚集行为中起重要作用。这些观察结果可能会为AGA的治疗带来新的治疗策略。
