Fibrotic skin disease represents a major global healthcare burden, characterized by fibroblast hyperproliferation and excessive accumulation of extracellular matrix. Fibroblasts are found to be heterogeneous in multiple fibrotic diseases, but fibroblast heterogeneity in fibrotic skin diseases is not well characterized. In this study, we explore fibroblast heterogeneity in keloid, a paradigm of fibrotic skin diseases, by using single-cell RNA-seq. Our results indicate that keloid fibroblasts can be divided into 4 subpopulations: secretory-papillary, secretory-reticular, mesenchymal and pro-inflammatory. Interestingly, the percentage of mesenchymal fibroblast subpopulation is significantly increased in keloid compared to normal scar. Functional studies indicate that mesenchymal fibroblasts are crucial for collagen overexpression in keloid. Increased mesenchymal fibroblast subpopulation is also found in another fibrotic skin disease, scleroderma, suggesting this is a broad mechanism for skin fibrosis. These findings will help us better understand skin fibrotic pathogenesis, and provide potential targets for fibrotic disease therapies.

BackgroundTransplantation of bone marrow-derived mesenchymal stem cells (BMSCs) is one of the new therapeutic strategies for treating ischemic stroke. However, the relatively poor migratory capacity of BMSCs toward infarcted regions limited the therapeutic potential of this approach. Pharmacological preconditioning can increase the expression of CXC chemokine receptor 4 (CXCR4) in BMSCs and enhance cell migration toward the injury site. In the present study, we investigated whether tetramethylpyrazine (TMP) preconditioning could enhance BMSCs migration to the ischemic brain and improve functional recovery through upregulating CXCR4 expression.MethodsBMSCs were identified by flow cytometry analysis. BMSCs migration was evaluated in vitro by transwell migration assay, and CXCR4 expression was measured by quantitative reverse transcription-polymerase chain reaction and western blot analysis. In rats with focal cerebral ischemia, the neurological function was evaluated by the modified neurological severity score, the adhesive removal test and the corner test. The homing BMSCs and angiogenesis were detected by immunofluorescence, and expression of stromal cell-derived factor-1 (SDF-1) and CXCR4 was measured by western blot analysis.ResultsFlow cytometry analysis demonstrated that BMSCs expressed CD29 and CD90, but not CD34 and CD45. TMP pretreatment dose-dependently induced BMSCs migration and CXCR4 expression in vitro, which was significantly inhibited by AMD3100, a CXCR4 antagonist. In rat stroke models, we found more TMP-preconditioned BMSCs homing toward the infarcted regions than nonpreconditioned cells, leading to improved neurological performance and enhanced angiogenesis. Moreover, TMP-preconditioned BMSCs significantly upregulated the protein expression of SDF-1 and CXCR4 in the ischemic boundary regions. These beneficial effects of TMP preconditioning were blocked by AMD3100.ConclusionTMP preconditioning enhances the migration and homing ability of BMSCs, increases CXCR4 expression, promotes angiogenesis, and improves neurological performance. Therefore, TMP preconditioning may be an effective strategy to improve the therapeutic potency of BMSCs for ischemic stroke due to enhanced BMSCs migration to ischemic regions.

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Long non-coding (lnc)RNA hypoxia inducible factor 1α-antisense RNA 1 (HIF1A-AS1) not only participates in different types of malignancies, but also serves pivotal roles in thoracic aortic aneurysms, which suggests its possible involvement in intracranial aneurysms. Therefore, the present study aimed to investigate its involvement in intracranial aneurysms. Expression levels of HIF1A-AS1 and transforming growth factor (TGF)-β1 in the blood of patients with intracranial aneurysms and healthy controls were detected using reverse transcription-quantitative polymerase chain reaction. The diagnostic value of blood HIF1A-AS1 for intracranial aneurysms was analyzed using receiver operating characteristic curve analysis. A HIF1A-AS1 expression vector was constructed and transfected into human vascular smooth muscle cells (VSMCs) and the effects on cell proliferation and TGF-β1 expression were explored using the Cell Counting kit-8 assay and western blot analysis, respectively. Upregulated HIF1A-AS1 expression levels in blood were observed in patients with intracranial aneurysms when compared with controls. Notably, upregulated HIF1A-AS1 expression effectively distinguished patients with intracranial aneurysms from healthy controls. Furthermore, HIF1A-AS1 and TGF-β1 expression levels were positively correlated with intracranial aneurysms. HIF1A-AS1 overexpression also upregulated TGF-β1 expression and inhibited VSMC proliferation. Although TGF-β1 treatment had no significant effect on HIF1A-AS1 expression, TGF-β inhibitor significantly reduced the effects of HIF1A-AS1 overexpression on cell proliferation. It was therefore concluded that HIF1A-AS1 may participate in intracranial aneurysms by regulating VSMC proliferation through the upregulation of TGF-β1.