Identifying the roles of hub gene in keloid formation using single-cell transcriptomics

Introduction: Keloid, a fibroproliferative tumor characterized by excessive collagen deposition and fibroblast hyperplasia, lacks effective therapeutic strategies due to unclear molecular mechanisms. Objective: This study aims to elucidate keloid pathogenesis and identify diagnostic biomarkers through multi-omics integration. Methods: Single-cell RNA sequencing (ScRNA-seq) data (GSE163973) and bulk RNA sequencing datasets (GSE162904/GSE145725) were analyzed. Fibroblast subpopulations were identified using the Seurat R package, and cell–cell interactions were explored using the CellChat R package. Weighted gene co-expression network analysis (WGCNA) was employed to identify key gene modules in fibroblasts. Hub genes were screened using Lasso regression and validated through machine learning algorithms and a gene-immune convolutional neural network (CNN). Immune infiltration patterns were evaluated using the MCP-counter and Immuno-Oncology Biological Research R packages. Results: ScRNA-seq analysis revealed eight distinct cell subtypes within keloid tissues, with fibroblasts significantly enriched compared to normal skin. Fibroblast clusters 1 and 5 exhibited elevated midkine–low-density lipoprotein receptor-related protein 1-mediated interactions and enhanced differentiation activity. WGCNA identified three critical modules—“brown,” “cyan,” and “yellow”—linked to fibroblast activation. Lasso regression produced an eight-gene signature that effectively distinguished keloid from normal skin (area under the curve = 0.885 – 0.889). Nonnegative matrix factorization classified keloids into four subtypes, each with distinct immune infiltration profiles correlated with hub gene expression. The gene-immune CNN model achieved 100% sensitivity and 88.9% specificity in diagnostic classification. Conclusion: This study elucidates the molecular mechanisms underlying keloid formation through integrated single-cell and transcriptomic analysis, proposing an eight-gene signature as a potential diagnostic and therapeutic target. The identified keloid subtypes and associated immune infiltration patterns provide novel insights for advancing precision medicine approaches in keloid management.
- Jing P. The Role of Splicing Factor SRSF2 in Keloid Fibroblasts. [Master’s Thesis]; 2019. p. 79.
- Asilian A, Darougheh A, Shariati F. New combination of triamcinolone, 5-fluorouracil, and pulsed-dye laser for treatment of keloid and hypertrophic scars. Dermatol Surg. 2006;32:907-915. doi: 10.1111/j.1524-4725.2006.32195.x
- Shih B, Bayat A. Genetics of keloid scarring. Arch Dermatol Res. 2010;302:319-339. doi: 10.1007/s00403-009-1014-y
- Supp DM, Hahn JM, Glaser K, McFarland KL, Boyce ST. Deep and superficial keloid fibroblasts contribute differentially to tissue phenotype in a novel in vivo model of keloid scar. Plast Reconstr Surg. 2012;129:1259-1271. doi: 10.1097/PRS.0b013e31824ecaa9
- Lim IJ, Phan TT, Bay BH, et al. Fibroblasts cocultured with keloid keratinocytes: Normal fibroblasts secrete collagen in a keloidlike manner. Am J Physiol Cell Physiol. 2002;283:C212-C222. doi: 10.1152/ajpcell.00555.2001
- Iqbal SA, Sidgwick GP, Bayat A. Identification of fibrocytes from mesenchymal stem cells in keloid tissue: A potential source of abnormal fibroblasts in keloid scarring. Arch Dermatol Res. 2012;304:665-671. doi: 10.1007/s00403-012-1225-5
- Ueda K, Furuya E, Yasuda Y, Oba S, Tajima S. Keloids have continuous high metabolic activity. Plast Reconstr Surg. 1999;104:694-698. doi: 10.1097/00006534-199909030-00012
- Van De Water L, Varney S, Tomasek JJ. Mechanoregulation of the myofibroblast in wound contraction, scarring, and fibrosis: Opportunities for new therapeutic intervention. Adv Wound Care (New Rochelle). 2013;2:122-141. doi: 10.1089/wound.2012.0393
- Tholpady SS, DeGeorge BR Jr., Campbell CA. The effect of local rho-kinase inhibition on murine wound healing. Ann Plast Surg. 2014;72:S213-S219. doi: 10.1097/SAP.0000000000000150
- Kao HK, Chen B, Murphy GF, Li Q, Orgill DP, Guo L. Peripheral blood fibrocytes: Enhancement of wound healing by cell proliferation, re-epithelialization, contraction, and angiogenesis. Ann Surg. 2011;254:1066-1074. doi: 10.1097/SLA.0b013e3182251559
- Wolfram D, Tzankov A, Pulzl P, Piza-Katzer H. Hypertrophic scars and keloids--a review of their pathophysiology, risk factors, and therapeutic management. Dermatol Surg. 2009;35:171-181. doi: 10.1111/j.1524-4725.2008.34406.x
- Van Leeuwen MC, Stokmans SC, Bulstra AJ, Meijer OW, Van Leeuwen PA, Niessen FB. High-dose-rate brachytherapy for the treatment of recalcitrant keloids: A unique, effective treatment protocol. Plast Reconstr Surg. 2014;134:527-534. doi: 10.1097/PRS.0000000000000415
- Halim AS, Emami A, Salahshourifar I, Kannan TP. Keloid scarring: Understanding the genetic basis, advances, and prospects. Arch Plast Surg. 2012;39:184-189. doi: 10.5999/aps.2012.39.3.184
- Wu Y, Wang B, Li YH, et al. Meta-analysis demonstrates association between arg72pro polymorphism in the p53 gene and susceptibility to keloids in the Chinese population. Genet Mol Res. 2012;11:1701-1711. doi: 10.4238/2012.June.29.2
- Messadi DV, Doung HS, Zhang Q, et al. Activation of nfkappab signal pathways in keloid fibroblasts. Arch Dermatol Res. 2004;296:125-133. doi: 10.1007/s00403-004-0487-y
- Lu F, Gao J, Ogawa R, Hyakusoku H, Ou C. Fas-mediated apoptotic signal transduction in keloid and hypertrophic scar. Plast Reconstr Surg. 2007;119:1714-1721. doi: 10.1097/01.prs.0000258851.47193.06
- Hu Z, Lou L, Luo S. [Experimental study of the expression of c-myc, c-fos and proto-oncogenes on hypertrophic and scars]. Zhonghua Zheng Xing Wai Ke Za Zhi. 2002;18:165-167.
- Teofoli P, Barduagni S, Ribuffo M, Campanella A, De Pita’O, Puddu P. Expression of bcl-2, p53, c-jun and c-fos protooncogenes in keloids and hypertrophic scars. J Dermatol Sci. 1999;22:31-37. doi: 10.1016/s0923-1811(99)00040-7
- Jin Z. Increased c-met phosphorylation is related to keloid pathogenesis: Implications for the biological behaviour of keloid fibroblasts. Pathology. 2014;46:25-31. doi: 10.1097/PAT.0000000000000028
- Xiaoyang M. Study on hypoxia/HIF-1α-induced EMT in keloid keratinocytes and its effect on invasiveness [Doctoral dissertation]. Peking Union Medical College; 2015.
- Aran D, Looney AP, Liu L, et al. Reference-based analysis of lung single-cell sequencing reveals a transitional profibrotic macrophage. Nat Immunol. 2019;20:163-172. doi: 10.1038/s41590-018-0276-y
- Morabito S, Reese F, Rahimzadeh N, Miyoshi E, Swarup V. Hdwgcna identifies co-expression networks in high-dimensional transcriptomics data. Cell Rep Methods. 2023;3:100498. doi: 10.1016/j.crmeth.2023.100498
- Jin S, Guerrero-Juarez CF, Zhang L, et al. Inference and analysis of cell-cell communication using cellchat. Nat Commun. 2021;12:1088. doi: 10.1038/s41467-021-21246-9
- Trapnell C, Cacchiarelli D, Grimsby J, et al. The dynamics and regulators of cell fate decisions are revealed by pseudotemporal ordering of single cells. Nat Biotechnol. 2014;32:381-386. doi: 10.1038/nbt.2859
- Lee DD, Seung HS. Learning the parts of objects by non-negative matrix factorization. Nature. 1999;401:788-791. doi: 10.1038/44565
- van Merriënboer B, Bahdanau D, Dumoulin V, et al. Blocks and Fuel: Frameworks for Deep Learning. arXiv preprint arXiv:1506.00619; 2015. doi: 10.48550/arXiv.1506.00619
- Heping H. Study on the Expression of Hedgehog Signaling Pathway and EMT-related lncRNAs in Keloids [Doctoral Dissertation]. Nanchang University; 2018.
- Vincent AS, Phan TT, Mukhopadhyay A, Lim HY, Halliwell B, Wong KP. Human skin keloid fibroblasts display bioenergetics of cancer cells. J Invest Dermatol. 2008;128:702-709. doi: 10.1038/sj.jid.5701107
- Murray JC. Keloids and hypertrophic scars. Clin Dermatol. 1994;12:27-37. doi: 10.1016/0738-081x(94)90254-2
- Slemp AE, Kirschner RE. Keloids and scars: A review of keloids and scars, their pathogenesis, risk factors, and management. Curr Opin Pediatr. 2006;18:396-402. doi: 10.1097/01.mop.0000236389.41462.ef
- Yahong C, Xiaoli W. Research progress in the mechanism of invasive growth of keloid. J Tissue Eng Reconstr Surg. 2015;11:335-338.
- Gang Z, Shaojun L, Shaoming T, Jie L, Qiang Z. Expression of BCL-2 in different parts of keloid and its significance. Guangdong Med. 2006:1811-1812.
- Sidgwick GP, Bayat A. Extracellular matrix molecules implicated in hypertrophic and keloid scarring. J Eur Acad Dermatol Venereol. 2012;26:141-152. doi: 10.1111/j.1468-3083.2011.04200.x
- Placik OJ, Lewis VJ Jr. Immunologic associations of keloids. Surg Gynecol Obstet. 1992;175:185-193.
- Niessen FB, Schalkwijk J, Vos H, Timens W. Hypertrophic scar formation is associated with an increased number of epidermal langerhans cells. J Pathol. 2004;202:121-129. doi: 10.1002/path.1502
- Han B. Study on the Effect and Molecular Mechanism of Paracrine Factors from Adipose-Derived Mesenchymal Stem Cells against Fibrosis of Pathological Scar Fibroblasts [Doctoral Dissertation]. Peking Union Medical College; 2018.