Carney Bonnie C, Chen Jason H, Luker Jenna N, Alkhalil Abdulnaser, Jo Daniel Y, Travis Taryn E, Moffatt Lauren T, Simbulan-Rosenthal Cynthia M, Rosenthal Dean S, Shupp Jeffrey W
Department of Biochemistry and Molecular and Cellular Biology, Georgetown University School of Medicine, Washington, District of Columbia.
Firefighters' Burn and Surgical Research Laboratory, MedStar Health Research Institute, Washington, District of Columbia.
J Burn Care Res. 2019 Jan 1;40(1):58-71. doi: 10.1093/jbcr/iry045.
Hypertrophic scar (HTS) occurs frequently after burn injury. Treatments for some aspects of scar morbidity exist, however, dyspigmentation treatments are lacking due to limited knowledge about why scars display dyschromic phenotypes. Full thickness wounds were created on duroc pigs that healed to form dyschromic HTS. HTS biopsies and primary cell cultures were then used to study pigmentation signaling. Biopsies of areas of both pigment types were taken for analysis. At the end of the experiment, melanocyte-keratinocyte cocultures were established from areas of differential pigmentation. Heterogeneously dyspigmented scars formed with regions of hyperpigmentation and hypopigmentation. Melanocytes were present in both pigment types measured by S100β quantitative real time-polymerase chain reaction (qRT-PCR) and immunostaining, and visualized by dendritic cell presence in primary cultures. P53 expression was not different between the two pigment types. Hyperpigmented scars had upregulated levels of proopiomelanocortin (POMC), adrenocorticotropic hormone (ACTH), α-melanocyte stimulating hormone (α-MSH), stem cell factor (SCF), and c-KIT and melanocortin 1 receptors (MC1R) compared to hypopigmented regions. Many genes involved in dyspigmentation were differentially regulated by microarray analysis including MITF, TYR, TYRP1, and DCT. MiTF expression was not different upon further exploration, but TYR, TYRP1, and DCT were upregulated in intact biopsies measured by qRT-PCR and confirmed by immunostaining. This is the first work to confirm the presence of melanocytes in hypopigmented scar using qRT-PCR and primary cell culture. An understanding of the initial steps in dyspigmentation signaling, as well as the downstream effects of these signals, will inform treatment options for patients with scars and provide insight to where pharmacotherapy may be directed.
肥厚性瘢痕（HTS）在烧伤后经常出现。虽然针对瘢痕发病的某些方面存在治疗方法，但由于对瘢痕为何呈现色素异常表型的了解有限，色素沉着异常的治疗方法仍很缺乏。在杜洛克猪身上制造全层伤口，伤口愈合后形成色素异常的肥厚性瘢痕。然后使用肥厚性瘢痕活检组织和原代细胞培养物来研究色素沉着信号传导。采集两种色素沉着类型区域的活检组织进行分析。在实验结束时，从色素沉着差异区域建立黑素细胞 - 角质形成细胞共培养物。形成了色素沉着不均一的瘢痕，有色素沉着过度和色素沉着不足的区域。通过S100β定量实时聚合酶链反应（qRT-PCR）和免疫染色测量，两种色素沉着类型中均存在黑素细胞，并通过原代培养中树突状细胞的存在来可视化。两种色素沉着类型之间的P53表达没有差异。与色素沉着不足区域相比，色素沉着过度的瘢痕中阿黑皮素原（POMC）、促肾上腺皮质激素（ACTH）、α - 黑素细胞刺激素（α - MSH）、干细胞因子（SCF）、c-KIT和黑素皮质素1受体（MC1R）的水平上调。通过微阵列分析发现，许多参与色素沉着异常的基因受到差异调节，包括小眼畸形相关转录因子（MITF）、酪氨酸酶（TYR）、酪氨酸酶相关蛋白1（TYRP1）和多巴色素互变酶（DCT）。进一步研究发现MITF表达没有差异，但通过qRT-PCR测量并经免疫染色证实，在完整活检组织中TYR、TYRP1和DCT上调。这是第一项使用qRT-PCR和原代细胞培养证实色素沉着不足瘢痕中存在黑素细胞的研究。了解色素沉着异常信号传导的初始步骤以及这些信号的下游效应，将为瘢痕患者提供治疗选择，并为药物治疗的方向提供见解。
