ObjectivePancreatic ductal adenocarcinoma (PDAC) shows a remarkable predilection for liver metastasis. Pro-oncogenic secretome delivery and trafficking via exosomes are crucial for pre-metastatic microenvironment formation and metastasis. This study aimed to explore the underlying mechanisms of how PDAC-derived exosomes (Pex) modulate the liver microenvironment and promote metastasis.DesignC57BL/6 mice were ‘educated’ by tail vein Pex injection. The intrasplenic injection liver metastasis and PDAC orthotopic transplantation models were used to evaluate liver metastasis. Stable cell lines CD44v6 (CD44 variant isoform 6) or C1QBP (complement C1q binding protein) knockdown or overexpression was established using lentivirus transfection or gateway systems. A total of 142 patients with PDAC in Huashan Hospital were retrospectively enrolled. Prognosis and liver metastasis were predicted using Kaplan-Meier survival curves and logistic regression models.ResultsPex tail vein injection induced the deposition of liver fibrotic extracellular matrix, which promoted PDAC liver metastasis. Specifically, the exosomal CD44v6/C1QBP complex was delivered to the plasma membrane of hepatic satellite cells (HSCs), leading to phosphorylation of insulin-like growth factor 1 signalling molecules, which resulted in HSC activation and liver fibrosis. Expression of Pex CD44v6 and C1QBP in PDAC patients with liver metastasis was significantly higher than in PDAC patients without liver metastasis, and simultaneous high expression of exosomal CD44v6 and C1QBP correlated with a worse prognosis and a higher risk of postoperative PDAC liver metastasis.ConclusionThe Pex-derived CD44v6/C1QBP complex is essential for the formation of a fibrotic liver microenvironment and PDAC liver metastasis. Highly expressed exosomal CD44v6 and C1QBP are promising biomarkers for predicting prognosis and liver metastasis in patients with PDAC.

Background: Postoperative hypertrophic scarring of the medial canthal area is a common phenomenon and deterrent for patients considering epicanthoplasty. Botulinum toxin type A has been reported for hypertrophic scar and keloid treatment. However, there is a lack of high-level evidence regarding the effects of botulinum toxin type A in the medial canthal area. Methods: In this split-face, double-blind, randomized trial, 43 consecutive consenting patients undergoing Park Z-epicanthoplasty were randomized to receive 5 U of botulinum toxin type A or the same volume of saline injections at days 6 to 7 postoperatively. Scars were assessed independently using the Vancouver Scar Scale, the visual analogue scale, and patient satisfaction rating at the 1-, 3-, and 6-month follow-ups. Results: Overall, 30 patients completed this trial. The botulinum toxin type A–treated side achieved significantly improved Vancouver Scar Scale scores. The most obvious improvements were observed at the 3-month follow-up visit. Among the four subscores of the Vancouver Scar Scale, the most significantly improved subscores were the height and pliability. The visual analogue scale scores also decreased significantly on the botulinum toxin type A–treated side at all three follow-up visits. Approximately 86.7 percent of the patients were satisfied with the scar and epicanthoplasty outcomes. No severe complications were reported. Conclusions: Early postoperative botulinum toxin type A injection in the medial canthal region efficiently reduces hypertrophic scarring and improves the outcome of epicanthoplasty. Therefore, botulinum toxin type A injection can be used as a routine method to prevent hypertrophic scarring and improve the outcome of epicanthoplasty. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, II.

Biomechanical force and pathological angiogenesis are dominant features in fibro-proliferative disorders. Understanding the role and regulation of the mechanical microenvironment in which pathological angiogenesis occurs is an important challenge when investigating numerous angiogenesis-related diseases. In skin fibrosis, dermal fibroblasts and vascular endothelial cells are integral to hypertrophic scar formation. However, few studies have been conducted to closely investigate their relationship. Here we show, that leucine-rich-alpha-2-glycoprotein 1 (LRG-1) a regulator of pathological angiogenesis, links biomechanical force to angiogenesis in skin fibrosis. We discover that LRG-1 is overexpressed in hypertrophic scar tissues, and that depletion of Lrg-1 in mouse skin causes mild neovascularization and skin fibrosis formation in a hypertrophic scarring model. Inhibition of FAK or ERK attenuates LRG-1 expression through the ELK1 transcription factor, which binds to the LRG-1 promoter region after transcription initiation by mechanical force. Using LRG-1 to uncouple mechanical force from angiogenesis may prove clinically successful in treating fibro-proliferative disorders.

Recombinant human bone morphogenetic protein-2 (rhBMP-2) is widely used in the clinic for bone defect reconstruction because of its powerful osteoinductive capacity. However, commercially available rhBMP-2 requires a high concentration in the clinical setting for consistent bone formation. A high dose of rhBMP-2 induces a promising bone formation yield but also leads to inflammation-related events, deteriorated bone quality, and fatty tissue formation. We hypothesize that the seemingly contradictory phenomenon of coformation of new bone and excessive adipose tissue in rhBMP-2-induced bone voids may be associated with interleukin-6 (IL-6), which is significantly elevated after application of rhBMP-2/absorbable collagen sponge (rhBMP-2/ACS). Here, we show that IL-6 injection enhances new bone regeneration and induces excessive adipose tissue formation in an rhBMP-2/ACS-induced ectopic bone formation model in rats. In vitro data further show that IL-6 and its soluble receptor sIL-6R synergistically augment rhBMP-2-induced osteogenic and adipogenic differentiation of human BMSCs (hBMSCs) by promoting cell surface translocation of BMPR1A and then amplifying BMPR1A-mediated BMP/Smad and p38 MAPK pathways, respectively. Our study suggests elevated IL-6 may be responsible for coformation of new bone and excessive adipose tissue in rhBMP-2-induced bone voids.

Re-epithelialization is a complex process during skin wound healing, and cell migration is an integral part of this phenomenon. Here we identified a role for LRG1 as a key regulator of epidermal keratinocyte migration where LRG1 acts via enhancement of HIF-1a stability. We showed that LRG1 is upregulated at murine skin wound edges and that addition of recombinant human LRG1 accelerates keratinocyte migration and skin wound healing. Furthermore, we identified transcription factor ELK3 as a downstream effector of LRG1. We confirmed that elevated ELK3 levels manipulated by LRG1 can promote cell migration through upregulation of HIF-1a stability. Because hyperglycemia complicatedly affects HIF-1a stability and activation, our findings provide insights into the molecular controls of wound-associated cell migration and identify potential therapeutic targets for the treatment of chronic diabetic wounds. In conclusion, we demonstrated that LRG1 promotes wound repair through keratinocyte migration and is important for normalization of an abnormal process of diabetic wound healing where HIF-1a stability is insufficient.

Obesity and its associated metabolic disorders such as diabetes, hepatic steatosis and chronic heart diseases are affecting billions of individuals. However there is no satisfactory drug to treat such diseases. In this study, we found that alisol A, a major active triterpene isolated from the Chinese traditional medicine Rhizoma Alismatis, could significantly attenuate high‐fat‐diet‐induced obesity. Our biochemical detection demonstrated that alisol A remarkably decreased lipid levels, alleviated glucose metabolism disorders and insulin resistance in high‐fat‐diet‐induced obese mice. We also found that alisol A reduced hepatic steatosis and improved liver function in the obese mice model.In addition, protein expression investigation revealed that alisol A had an active effect on AMPK/ACC/SREBP‐1c pathway. As suggested by the molecular docking study, such bioactivity of alisol A may result from its selective binding to the catalytic region of AMPK.Therefore, we believe that Alisol A could serve as a promising agent for treatment of obesity and its related metabolic diseases.

The in vivo bioreactor principle, which focuses on using the body as a living bioreactor to cultivate stem cells, bioscaffolds, and growth factors and leveraging the body’s self-regenerative capacity to regenerate new tissue, has been considered a potential approach for bone defect reconstruction. The histological characteristics of the periosteum allow it to possess a remarkable capacity to induce bone growth and remodeling, making it suitable as an in vivo bioreactor strategy for bone graft prefabrication. The present study was designed to prefabricate vascularized bone grafts using pedicled periosteal flaps and decellularized bone matrix (DBM) scaffolds in a rabbit model. The muscular pouches created in the femoral muscle were acted as a control. Our histological results revealed that both the periosteal flap group and muscular pouch group induced bone tissue formation on the DBM surface at both 8 and 16 weeks postoperatively. However, micro-computed tomography (microCT) scanning, biomechanical, and histomorphometric findings indicated that bone grafts from the periosteal flap group showed larger bone mass, faster bone formation rates, higher vascular density, and stronger biomechanical properties than in the muscular pouch group. We suggest that using the pedicled periosteal flap as an in vivo bioreactor is a promising approach for functional bone graft prefabrication.

Transforming growth factor-β (TGF-β) signaling plays a key role in excessive fibrosis. As a class IIa family histone deacetylase (HDAC), HDAC5 shows a close relationship with TGF-β signaling and fibrosis. However, the effect and regulatory mechanism of HDAC5 in hypertrophic scar (HS) formation remain elusive. We show that HDAC5 was overexpressed in HS tissues and depletion of HDAC5 attenuated HS formation in vivo and inhibited fibroblast activation in vitro. HDAC5 knockdown (KD) significantly downregulated TGF-β1 induced Smad2/3 phosphorylation and increased Smad7 expression. Meanwhile, Smad7 KD rescued the Smad2/3 phosphorylation downregulation and scar hyperplasia inhibition mediated by HDAC5 deficiency. Luciferase reporter assays and ChIP-qPCR assays revealed that HDAC5 interacts with myocyte enhancer factor 2A (MEF2A) suppressing MEF2A binding to the Smad7 promoter region, which results in Smad7 promoter activity repression. HDAC4/5 inhibitor, LMK235, significantly alleviated hypertrophic scar formation. Our study provides clues for the development of HDAC5 targeting strategies for the therapy or prophylaxis of fibrotic diseases.