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Background: Keloid represents a benign skin tumor with many cancer‐like features. Extracellular vesicles (EVs) derived from human adipose‐derived stem cells (hADSCs) play a role in cell migration of multiple diseases. Aims: This study aimed to investigate the impact of hADSC‐EVs on human keloid fibroblasts (HKFs). Methods: hADSCs were cultured to the 3rd generation, and subsequently assessed for their osteogenic, adipogenic, and chondrogenic differentiative abilities using flow cytometry, alizarin red, oil red O, and alcian blue staining techniques. hADSC‐EVs were isolated through ultracentrifugation and subsequently identified. HKFs at the 3rd generation were subjected to treatment with hADSC‐EVs to observe their endocytosis of EVs by immunofluorescence. CCK‐8, wound healing, and Transwell assays were performed to test HKF proliferation and migration. The levels of autophagy proteins, collagens, and Janus kinase 2 (JAK2) and Signal Transducer and Activator of Transcription 3 (STAT3) were determined through Western blot analysis. Suppressor of cytokine signaling 1 (SOCS1) expression was determined by RT‐qPCR and Western blot. Results: hADSC‐EVs were successfully isolated from hADSCs. PKH67‐labeled hADSC‐EVs were observed to be endocytosed by HKFs, resulting the inhibition of HKF proliferation, migration, as well as a reduction in collagen deposition. hADSC‐EVs carried SOCS1 into HKFs to suppress HKF autophagy. SOCS1 downregulation in hADSC‐EVs partially nullified the inhibitory effect of hADSC‐EVs on HKFs. hADSC‐EV‐carried SOCS1 inhibited the activation of the JAK2/STAT3 pathway. JAK2/STAT3 pathway activation partially abrogated the suppression of hADSC‐EVs on the proliferation, migration, and collagen deposition of HKF. Conclusion: hADSC‐EVs carried SOCS1 into HKFs and suppressed HKF autophagy, proliferation, migration, and collagen deposition by inactivating the JAK2/STAT3 pathway. [ABSTRACT FROM AUTHOR]

Keloid is a fibroproliferative disorder resulting from trauma, characterized by abnormal activation of keloid fibroblasts and excessive deposition of extracellular matrix (ECM). It affects life quality of patients and lacks of effective therapeutic targets. Protein tyrosine phosphatase 1B (PTP1B) belongs to the protein tyrosine phosphatases and participates in many cellular processes such as metabolism, proliferation and motility. It has been reported that PTP1B negatively regulated diabetic wound healing and tumor progression. However, its effects in keloid remain unclear. Here, we aimed to evaluate the effects of PTP1B on keloid fibroblasts which play essential roles in keloids pathogenesis. Our results revealed that PTP1B expression was decreased both in keloid tissues and in keloid fibroblasts compared to healthy controls. Keloid fibroblasts (KFs) showed higher cell proliferation, motility, ECM production and ERK activity than normal fibroblasts (NFs). Overexpression of PTP1B in KFs and NFs inhibited cell proliferation, motility, ECM synthesis and the MAPK/ERK signalling pathway while knockdown of PTP1B showed converse effects. The rescue experiments with ERK inhibitor further verified that MAPK/ERK signalling pathway involved in PTP1B regulatory network. Taken together, our findings indicated that overexpression of PTP1B suppressed keloid fibroblasts bio‐behaviours and promoted their phenotype switch to normal cells via inhibiting the MAPK/ERK signalling pathway, suggesting it may be a potential anti‐keloid therapy. [ABSTRACT FROM AUTHOR]

Apoptosis plays a key role in keloids. Growth arrest and DNA damage‐inducible gene 153 (GADD153) is regulated by apoptosis. Botulinum toxin type A (BTXA) can induce apoptosis in keloid fibroblasts. This research aimed to explore the hypothesis that GADD153 mediates apoptosis in keloid fibroblasts exposed to BTXA. BTXA significantly induced GADD153 protein and mRNA expression in keloid fibroblasts. Treatment with c‐Jun N‐terminal kinase (JNK) inhibitor SP600125, JNK small interfering RNA (siRNA) and tumour necrosis factor‐alpha (TNF‐α) antibodies reversed the BTXA‐induced GADD153 expression. BTXA enhanced the transcriptional activity of GADD153, whereas the GADD153 mutant plasmid, JNK siRNA and anti‐TNF‐α antibody treatment abolished the BTXA‐induced transcriptional activity of GADD153. The addition of TNF‐α to keloid fibroblasts markedly increased GADD153 protein expression. The addition of GADD153 siRNA, SP600125 and anti‐TNF‐α antibodies reversed cell death and caspase 3 and 9 activity induced by BTXA. [ABSTRACT FROM AUTHOR]

Keloids are a common type of pathological skin healing, characterized by the destruction of the vascular network. Thus, keloids often exhibit anoxic conditions. Hypoxia‐inducible factor‐1α (HIF‐1α) is a core factor that mediates hypoxia stress responses and allows the cells to adapt to low‐oxygen conditions. In the current study, we identified that Parkin acted as an E3 ubiquitin ligase, contributing to the degradation of HIF‐1α in keloid fibroblasts (KFs). Silencing of Parkin in KFs upregulated HIF‐1α expression and prolonged its protein half‐life. Furthermore, Parkin influenced transforming growth factor β (TGF‐β)/Smad signaling by targeting HIF‐1α. Under hypoxic conditions, silencing Parkin enhanced KF proliferation and inhibited apoptosis through the TGF‐β/Smad signaling pathway. Notably, metformin, an antidiabetic drug, could significantly induce Parkin expression and enhance the interaction between Parkin and HIF‐1α. As a result, we revealed an important mechanism for Parkin in keloid development and suggested that targeting Parkin could be an alternative method for keloid treatment. [ABSTRACT FROM AUTHOR]

Topography modified cell behavior remains less explored in diseased cells. This study investigated the reversing effect on the pathological phenotype of keloid fibroblasts via culturing cells on a parallel microgrooved surface. The results showed that this particular topography with 3 μm groove depth and 10 μm width could significantly elongate and align the cultured cells with reduced cell (nucleus) area and increased cell (nucleus) body aspect ratio and cell (nucleus) body major axis (p < 0.05). Importantly, the elongated cells gradually lost their fibrotic phenotype with inhibited cell proliferation and cell cycle arrest in S‐phase (p < 0.05), reduced expression of fibrotic markers such as collagen, fibronectin, connective tissue growth factor, α‐smooth muscle actin, transforming growth factor‐β1 (p < 0.05), and increased matrix metalloproteinases/tissue inhibitor‐1 ratio (p < 0.05) along with attenuated Smad and Erk phosphorylation level. All these indicate that this parallel topography is powerful enough to modify keloid cell phenotype, a benign skin tumor with excessive cell proliferation and matrix production. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2019. [ABSTRACT FROM AUTHOR]

Keloids are characterised by the excessive accumulation of extracellular matrix ( ECM), especially overabundant collagen formation. In keloid fibroblasts ( KFs), transforming growth factor ( TGF)-β-dependent signalling is closely associated with a variety of keloid pathologic responses such as ECM production and fibroblast overgrowth. Thus, inhibition of TGF-β signalling would be a potential therapeutic approach to prevent keloid scar formation. Thereby, we aimed to identify a novel TGF-β signalling blocker among natural products using a simplified screening approach. We discovered that the extract of Aneilema keisak ( A. K- Ex) lowered TGF-β-dependent signalling by reducing Smad2 protein levels. Given that KFs showed altered dependency on TGF-β for survival and proliferation, A. K- Ex-mediated reduction in Smad2 protein levels significantly inhibited the major characteristics of KFs such as cell growth, migration and collagen synthesis, suggesting that A. K- Ex exhibits possible therapeutic activity on keloids. [ABSTRACT FROM AUTHOR]