Endogenous peptide LYENRL prevents the activation of hypertrophic scar-derived fibroblasts by inhibiting the TGF-β1/Smad pathway

The Role of Tenascin-C in Hypertrophic Scar Formation: Insights from Cell and Animal Experiments

Background

Hypertrophic scars (HS) are dermal diseases characterized by excessive fibroblast proliferation and collagen deposition following burns or trauma. While Tenascin-C (TNC)'s role in promoting visceral fibrosis has been established, its impact on skin tissue fibrosis remains unclear. This study aims to investigate the effects of TNC on HS.

Methods

RNA sequence and IHC techniques were used to examine the upregulation of TNC gene in human hypertrophic scar tissue compared to normal tissues. Knockdown of TNC in Human skin fibroblasts (HFF-1) cells was achieved, and expression of Col1 and Col3 was evaluated using qPCR. Sirius red collagen staining assessed impact on total collagen content and ECM deposition. Effects on cell proliferation and migration were investigated through cck-8 and cell scratch experiments. Lentivirus infection was used to knock out TNC, and resulting samples were injected into ear wound of rabbits. Effects of TNC knockout on ear scar formation were measured using digital morphology, ultrasound, SEI, H&E, and Masson trichrome methods.

Results

Cell experiments: downregulation of TNC decreased Col1 and Col3 expression, leading to reduced collagen production and extracellular matrix deposition. It did not affect HFF-1 cell proliferation and migration. Animal experiments: TNC knockdown promoted wound healing and reduced collagen deposition in rabbit ears.

Conclusion

This study suggests that knocking down TNC inhibits collagen formation and extracellular matrix deposition, thereby inhibiting hypertrophic scar formation. Therefore, TNC can be considered a potential biomarker for HS formation and may offer promising treatment strategies for clinical management of hypertrophic scars.

The recent progress of peptide regulators for the Wnt/β-catenin signaling pathway

Wnt signaling plays an important role in many biological processes such as stem cell self-renewal, cell proliferation, migration, and differentiation. The β-catenin-dependent signaling pathway mainly regulates cell proliferation, differentiation, and migration. In the Wnt/β-catenin signaling pathway, the Wnt family ligands transduce signals through LRP5/6 and Frizzled receptors to the Wnt/β-catenin signaling cascades. Wnt-targeted therapy has garnered extensive attention. The most commonly used approach in targeted therapy is small-molecule regulators. However, it is difficult for small-molecule regulators to make great progress due to their inherent defects. Therapeutic peptide regulators targeting the Wnt signaling pathway have become an alternative therapy, promising to fill the gaps in the clinical application of small-molecule regulators. In this review, we describe recent advances in peptide regulators for Wnt/β-catenin signaling.

Peptide deregulated in hypertrophic scar-1 alleviates hypertrophic scar fibrosis by targeting focal adhesion kinase and pyruvate kinase M2 and remodeling the metabolic landscape

Hypertrophic scarring is a fibrotic skin disease characterized by excessive deposition of collagens. Emerging evidence has suggested important roles for peptides in fibrosis-related diseases. Here, we demonstrate that a skin-derived endogenous peptide, peptide deregulated in hypertrophic scar-1 (PDHS1), with the sequence IATTTASAATAAAIGATPRAK, inhibits cell proliferation, promotes apoptosis, decreases the proportion of cells in S phase, and decreases collagen synthesis in hypertrophic scar fibroblasts. Additionally, treatment with PDHPS1 alleviates hypertrophic scarring in a rabbit ear model. PDHPS1 was found to bind to focal adhesion kinase (FAK) and to decrease its activity. PDHPS1 was also shown to bind to pyruvate kinase M2 (PKM2) and to decreased its expression. Smad2 phosphorylation is also inhibited by treatment with PDHPS1. Overexpression of FAK rescues the decreased expression of COL3A1 induced by PDHPS1 treatment. Targeted metabolomics revealed that PDHPS1 reprogramed metabolism that related to amino acid synthesis, leading to decreases of the key glycolysis intermediates glucose-6-phosphate and fructose-6-phosphate. These results demonstrated that the endogenous peptide PDHPS1 alleviates hypertrophic scar fibrosis in vitro and in vivo by targeting FAK and PKM2 and remodeling the metabolic landscape. Overall, treatment with PDHPS1 is a potential therapeutic strategy for hypertrophic scarring.

Complexing the Pre-assembled Brush-like siRNA with Poly(β-amino ester) for Efficient Gene Silencing

Small interfering RNA (siRNA) has been emerging as a highly selective and effective pharmaceutics for treating broad classes of diseases. However, the practical application of siRNA agent is often hampered by its poor crossing of the cellular membrane barrier and ineffective releasing from endosome to cytoplasm, leading to low gene silencing efficacy for clinical purposes. Thus far, cationic lipid and polymer-based vectors have been extensively explored for gene delivery. Yet condensing the rigid and highly negatively charged siRNA duplex to form a stable complex vehicle usually requires a large load of cationic carriers, prone to raising the toxicity issue for delivery. Herein, we develop a simple strategy that can efficiently condense the siRNAs into nanoparticle vehicles for target gene regulation. In this approach, we first employ a DNA-grafted polycaprolactone (DNA-g-PCL) brush as template to organize the small rigid siRNAs into a large brush-like structure (siRNA-brush) through nucleic acid hybridization. Then, the siRNA-brush assembly is condensed by an ionizable and biodegradable polymer (poly(β-amino ester), PBAE) under acidic buffer condition to form a stable nanoparticle for siRNA delivery. Compared to the free siRNAs with poor complexing capability with PBAE, the large brush-like siRNA assemblies with more complicated topological architecture significantly promotes their electrostatic interaction with PBAE, enabling the formation of complexed nanoparticles at low weight ratio of polymer to siRNA. Additionally, PBAE/siRNA-brush complexes exhibit good biocompatibility and stability under physiological condition, as well as enhanced cellular internalization. When equipped with functional siRNAs, the obtained delivery system demonstrates excellent downregulation of target genes both in vitro and in vivo, through which the progression of hypertrophic scars can be retarded with negligible adverse effects in an xenografted mouse model.

Vitamin C Enema Advances Induction of Remission in the Dextran Sodium Sulfate-Induced Colitis Model in Rats

The current main treatment for ulcerative colitis (UC) is induction therapy by long-term administration of 5-aminosalicylic acid (5-ASA), but various side effects have been reported. Therefore, a radical cure for UC is desired. A vitamin C (VC) has anti-inflammatory effects. Therefore, this study investigated whether a VC solution enema shortens induction of remission in colitis model rats. Wistar rats (6 wk old/male) were allowed to freely ingest a 1% dextran sulfate sodium (DSS) solution for 10 d and then switched to tap water for normal breeding for 10 d (UC group). At the time of switching to tap water, an enema was performed with a 5-ASA solution (40 mg/kg/d) or VC solution (460 mg/kg/d) for 10 d. The neutrophil number, COX-2, which is an index of inflammation, and type III collagen, which is an early healing marker, were significantly increased in the UC group. However, the VC group showed decreases compared with UC groups. Furthermore, compared with UC and 5-ASA groups, the VC group showed increased expression of type I collagen, which is expressed late in healing, and significant epithelial regeneration was observed in colon tissue. The VC solution enema shortened the induction of remission by directly suppressing inflammation of damaged large intestinal tissues and promoting mucosal healing.

Knockdown of lysyl oxidase like 1 inhibits the proliferation and pro-fibrotic effects of Transforming growth factor-β1-induced hypertrophic scar fibroblasts

BACKGROUND

The excessive healing response during wound repair can result in hypertrophic scars (HS). Lysyl oxidase like 1 (LOXL1) has been reported to be associated with fibrosis via targeting TGF-β1 signaling. This study aimed to investigate the effect of LOXL1 on HS formation.

METHODS

The expression of LOXL1 in HS tissues and TGF-β1-induced HSFs was detected via RT-qPCR and western blot. LOXL1 was silenced in HSFs using transfection with short hairpin RNA (shRNA), then wound healing process including cell proliferation, cell cycle distribution, migration and extracellular matrix deposition along with Smad expression were measured by CCK-8, EdU staining, flow cytometry, transwell, immunofluorescence and western blot assays.

RESULTS

LOXL1 was up-regulated in HS tissues and TGF-β1-induced HSFs. Knockdown of LOXL1 inhibited proliferation and migration, but promoted cell cycle G0/G1 phase arrest in TGF-β1-induced HSFs. The increased expression of cyclin D1, CDK4, MMP2, MMP9, COL1A1, COL1A2, fibronectin, COL3A1, α-SMA, but decreased expression of p27, and the phosphorylation of Smad2 and Smad3 caused by TGF-β1 were also blocked by LOXL1 silence.

CONCLUSIONS

Silence of LOXL1 could effectively inhibit TGF-β1-induced proliferation, migration and ECM deposition in HSFs via inactivating Smad pathway. Targeting LOXL1 may have future therapeutic implications for HS treatment.

Purification of Gekko Small Peptide Fraction and Its Effect of Inducing Apoptosis of EC 9706 Esophageal Cancer Cells by Inhibiting PI3K/Akt/GLUT1 Signaling Pathway

This study aimed to isolate and purify a cytotoxic extraction from Gekko japonicus, identify its components and determine its cytotoxic activity in vitro. We isolated and identified the most potent cytotoxic Gekko small peptide LH-20-15. The identification and analysis of peptide sequences of LH-20-15 were performed by de novo peptide sequencing, and two new peptides were found. LH-20-15 significantly inhibited the proliferation of human esophageal squamous carcinoma EC 9706 cells in a dose-dependent manner. Furthermore, LH-20-15 induced apoptosis in esophageal cancer cells by activating the mitochondrial apoptotic pathway. Further research showed that LH-20-15 inhibited the PI3 K/Akt/GLUT1 signaling pathway. In conclusion, LH-20-15 from Gekko japonicus is a peptide mixture and may inhibit EC 9706 cell proliferation and induce apoptosis by activating the mitochondrial apoptotic pathway. It also regulates glucose metabolism by targeting the PI3 K/Akt/GLUT1 signaling pathway. These small peptides could be new sources of natural cytotoxic ingredients against esophageal cancer with potential drug values.

Emerging evidence for the roles of peptide in hypertrophic scar

Hypertrophic scar is a dermal fibroproliferative disorder characterized by excess collagen deposition. There are many existing treatment modalities, but none works perfectly in all individuals. Recently, evidence is increasing that peptides can play crucial roles in the prevention or treatment of hypertrophic scar. The peptides may be derived from growth factors, hormones, and intracellular products of proteolysis. In vitro and in vivo studies have revealed that a number of peptides, usually topically applied, have beneficial effects on fibroblasts in rat, mouse, hamster, pig and rabbit scar models. The length of such peptides typically ranges between 10 and 15 amino acids (aa). Peptides may reduce scar progenitors, prevent excessive scarring, decrease scar growth, speed re-epithelialization and promote scar maturation through multiple mechanisms. They may target TGF-β signaling, fibroblast function or collagen modulation, inflammation, renin angiotensin system, gap junction and other pathways. However, there is a paucity of evidence regarding specific binding sites for these peptides in scar models. Here, we review current research progress on the roles of peptides and underlying mechanisms in hypertrophic scar. We also discuss the clinical potential of peptides as therapeutic agents in scarring. Finally, the functions of several peptide-related compounds in hypertrophic scar are summarized.