High Expression of SERPINE1 and CTSL in Keratinocytes in Pressure Injury Caused by Ischemia-reperfusion Injury

Pressure Injury (PI) is a complex disease process which is influenced by multiple factors, among which ischemia-reperfusion (I/R) injury is closely related to the progression of PI. But, its biomarkers are still unclearly. Understanding its physiological mechanisms and related molecular biomarkers is the key to developing effective prevention and therapeutic strategies. This study through obtained the candidate genes of the differentially expressed genes (DEGs) from the PI rat model by transcriptome sequencing, PI single-cell sequencing database, and genes related to ischemic-reperfusion (I/R) injury from GeneCards database to analyze and screen prognostic related target genes. There were finally 7 candidate genes obtained from the intersection of the three datasets. Gene Ontology (GO) and Kyoto Encyclopedia of Genomes (KEGG) pathway analysis revealed that the DEGs were enriched in complement and coagulation cascades, and the keratinocyte differentiation is a significant factor. Then, two hub genes Serine protease inhibitor clade E member 1 (SERPINE1) and Cathepsin L (CTSL) were identified through three machine learning algorithms. The two hub genes were assessed using the nomogram and Receiver Operating Characteristic (ROC) approaches, and the findings indicated that these two genes had a high prognosis value. The two genes both play crucial roles in vasculogenesis, coagulation and degradation of the extracellular matrix, which is essential for wound healing. The results of immunohistochemistry demonstrated that SERPINE1 and CTSL are significantly upregulated in skin tissue from PI caused by I/R injury, and their mRNA expression levels significantly correlate with PI outcomes. According to our research we referred that the SERPINE1 and CTSL might be the potential biomarkers of PI.压力性损伤（Pressure Injury, PI）是一种受多重因素影响的复杂病理进程，其中缺血再灌注（ischemia-reperfusion, I/R）损伤与PI的发生发展密切相关，但其生物标志物仍未明确。阐明其生理机制及相关分子生物标志物，是开发有效防治策略的关键。本研究通过转录组测序获取压力性损伤大鼠模型的差异表达基因（differentially expressed genes, DEGs）候选基因、调取PI单细胞测序数据库，并从GeneCards数据库获取缺血再灌注损伤相关基因，以分析筛选预后相关靶基因。最终从三个数据集的交集中共获得7个候选基因。基因本体（Gene Ontology, GO）富集分析与京都基因与基因组百科全书（Kyoto Encyclopedia of Genes and Genomes, KEGG）通路分析结果显示，差异表达基因主要富集于补体与凝血级联反应通路，且角质形成细胞分化为关键影响因素。随后通过三种机器学习算法，筛选得到两个核心基因：丝氨酸蛋白酶抑制剂E家族成员1（Serine protease inhibitor clade E member 1, SERPINE1）与组织蛋白酶L（Cathepsin L, CTSL）。采用列线图与受试者工作特征（Receiver Operating Characteristic, ROC）曲线对这两个核心基因进行评估，结果表明二者均具有较高的预后价值。这两个基因均在血管生成、凝血及细胞外基质降解过程中发挥关键作用，而这些过程对伤口愈合至关重要。免疫组织化学检测结果显示，在缺血再灌注损伤所致PI的皮肤组织中，SERPINE1与CTSL的表达显著上调，且其mRNA表达水平与PI预后显著相关。本研究提示，SERPINE1与CTSL有望成为PI的潜在生物标志物。