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Background: Keloid, a fibroproliferative disorder, significantly impacts patients' quality of life, yet effective therapies remain elusive. This study explored the role of silent information regulator 6 (SIRT6) in modulating the proliferation, invasion, and collagen synthesis of keloid fibroblasts., Methods: Keloid and normal skin specimens were collected, and fibroblasts were isolated from the keloid tissue. SIRT6 recombinant adenovirus (Ad) was constructed to infect keloid fibroblasts to overexpress SIRT6. This study entails three groups: Control group, adenovirus-Negative Control (Ad-NC) group, and Ad-SIRT6 group. SIRT6 protein and mRNA levels were measured via Western blotting and Quantitative reverse transcription polymerase chain reaction (qRT-PCR), respectively. Cell viability was determined using 5-ethynyl-2'-deoxyuridine (EdU) assay. Flow cytometry was exploited to measure cell apoptosis. To investigate cell migration, wound healing assay and Transwell assay were employed. Western blotting was also utilized to study the expression levels of apoptotic proteins, collagen deposition-related proteins, and Mitogen-Activated Protein Kinases (MAPK)/extracellular regulated protein kinases (ERK) pathway-related proteins., Results: Compared to the control and Ad-NC groups, the Ad-SIRT6 group exhibited significantly elevated SIRT6 level; diminished cell proliferation, migration and invasion; reduced protein levels of α-smooth muscle actin (α-SMA), collagen I, collagen III, phospho SMAD Family Member 3 (p-Smad3), transforming growth factor-β 1 (TGF-β1), and MAPK/ERK pathway proteins (phospho extracellular signal-regulated protein kinase 1/2 (p-ERK1/2), phospho MAP kinase-ERK kinase (p-MEK) and phospho-c-Raf (p-c-Raf)). Treatment with epidermal growth factor (EGF), an MAPK/ERK pathway agonists, reversed the inhibitory effect of SIRT6 on cell activity and inhibited apoptosis in keloid fibroblasts., Conclusion: SIRT6 overexpression in keloid fibroblasts attenuates proliferation, invasion, and collagen synthesis, while fostering apoptosis, likely through the suppression of MAPK/ERK pathway activity. This suggests a potential therapeutic target for keloid treatment.

Poly L-lactic acid (PLLA) fillers stimulate collagen synthesis by activating various immune cells and fibroblasts. Piezo1, an ion channel, responds to mechanical stimuli, including changes in extracellular matrix stiffness, by mediating Ca 2+ influx. Given that elevated intracellular Ca 2+ levels trigger signaling pathways associated with fibroblast proliferation, Piezo1 is a pivotal regulator of collagen synthesis and tissue fibrosis. The aim of the present study was to investigate the impact of PLLA on dermal collagen synthesis by activating Piezo1 in both an H 2 O 2 -induced cellular senescence model in vitro and aged animal skin in vivo. PLLA elevated intracellular Ca 2+ levels in senescent fibroblasts, which was attenuated by the Piezo1 inhibitor GsMTx4. Furthermore, PLLA treatment increased the expression of phosphorylated ERK1/2 to total ERK1/2 (pERK1/2/ERK1/2) and phosphorylated AKT to total AKT (pAKT/AKT), indicating enhanced pathway activation. This was accompanied by upregulation of cell cycle-regulating proteins (CDK4 and cyclin D1), promoting the proliferation of senescent fibroblasts. Additionally, PLLA promoted the expression of phosphorylated mTOR/S6K1/4EBP1, TGF-β, and Collagen I/III in senescent fibroblasts, with GsMTx4 treatment mitigating these effects. In aged skin, PLLA treatment similarly upregulated the expression of pERK1/2/ERK1/2, pAKT/AKT, CDK4, cyclin D1, mTOR/S6K1/4EBP1, TGF-β, and Collagen I/III. In summary, our findings suggest Piezo1's involvement in PLLA-induced collagen synthesis, mediated by heightened activation of cell proliferation signaling pathways such as pERK1/2/ERK1/2, pAKT/AKT, and phosphorylated mTOR/S6K1/4EBP1, underscoring the therapeutic potential of PLLA in tissue regeneration.

Arsenic exposure is connected with lung toxicity and is related to lung fibrotic changes. Idiopathic pulmonary fibrosis (IPF) is characterized by extracellular matrix (ECM) deposition. Various genetic mechanisms and environmental factors induce or exacerbate pulmonary fibrosis. Collagen synthesis induced by sodium arsenite (NaAsO 2 ) is closely associated with IPF. Fibroblasts tend to fine-tune their metabolic networks to support their synthetic requirements in response to environmental stimuli. Alterations in metabolism have an influential role in the pathogenesis of IPF. However, it is unclear how arsenic affects the metabolism in IPF. The urea cycle (UC) is needed for collagen formation, which provides adequate levels of proline (Pro) for biosynthesis of collagen. Carbamoyl phosphate synthetase 1 (CPS1) converts the ammonia to carbamoyl phosphate, which controls the first reaction of the UC. We show that, in arsenite-exposed mice, high amounts of ammonia in the lung microenvironment promotes the expression levels of CPS1 and the Pro metabolism. Reduction of ammonia and CPS1 ablation inhibit collagen synthesis and ameliorate IPF phenotypes induced by arsenite. This work takes advantage of multi-omics data to enhance understanding of the underlying pathogenic mechanisms, the key molecules and the complicated cellular responses to this pollutant, which provide a target for the prevention of pulmonary fibrosis caused by arsenic., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Objective: The aim of this study was to comprehensively examine and summarize the available in vitro evidence regarding the relationship between mechanical stimulation and biomarkers of collagen synthesis in human-derived tendon cells., Methods: Systematic review with narrative analyses and risk of bias assessment guided by the Health Assessment and Translation tool. The electronic databases MEDLINE (Ovid), EMBASE (Ovid), CENTRAL (Ovid) and COMPENDEX (Engineering Village) were systematically searched from inception to 3 August 2023. Inclusion criteria encompassed English language, original experimental, or quasi-experimental in vitro publications that subjected human tendon cells to mechanical stimulation, with collagen synthesis (total collagen, type I, III, V, XI, XII, and XIV) and related biomarkers (matrix metalloproteinases, transforming growth factor β, scleraxis, basic fibroblast growth factor) as outcomes., Results: Twenty-one publications were included. A pervasive definite high risk of bias was evident in all included studies. Owing to incomplete outcome reporting and heterogeneity in mechanical stimulation protocols, planned meta-analyses were unfeasible. Reviewed data suggested that human tendon cells respond to mechanical stimulation with increased synthesis of collagen (e.g., COL1A1, procollagen, total soluble collagen, etc.), scleraxis and several matrix metalloproteinases. Results also indicate that mechanical stimulation dose magnitude may influence synthesis in several biomarkers., Conclusions: A limited number of studies, unfortunately characterized by a definite high risk of bias, suggest that in vitro mechanical stimulation primarily increases type I collagen synthesis by human tendon cells. Findings from this systematic review provide researchers and clinicians with biological evidence concerning the possible beneficial influence of exercise and loading on cellular-level tendon adaptation.

Excessive deposition of extracellular matrix, mainly collagen protein, is the hallmark of organ fibrosis. The molecular mechanisms regulating fibrotic protein biosynthesis are unclear. Here, we find that chemoattractant receptor homologous molecule expressed on TH2 cells (CRTH2), a plasma membrane receptor for prostaglandin D2, is trafficked to the endoplasmic reticulum (ER) membrane in fibroblasts in a caveolin-1-dependent manner. ER-anchored CRTH2 binds the collagen mRNA recognition motif of La ribonucleoprotein domain family member 6 (LARP6) and promotes the degradation of collagen mRNA in these cells. In line, CRTH2 deficiency increases collagen biosynthesis in fibroblasts and exacerbates injury-induced organ fibrosis in mice, which can be rescued by LARP6 depletion. Administration of CRTH2 N-terminal peptide reduces collagen production by binding to LARP6. Similar to CRTH2, bumetanide binds the LARP6 mRNA recognition motif, suppresses collagen biosynthesis, and alleviates bleomycin-triggered pulmonary fibrosis in vivo. These findings reveal a novel anti-fibrotic function of CRTH2 in the ER membrane via the interaction with LARP6, which may represent a therapeutic target for fibrotic diseases., (© 2021 The Authors.)

Endothelial cell injury is an early event in systemic sclerosis (SSc) pathogenesis and several studies indicate oxidative stress as the trigger of SSc-associated vasculopathy. Here, we show that circulating factors present in sera of SSc patients increased reactive oxygen species (ROS) production and collagen synthesis in human pulmonary microvascular endothelial cells (HPMECs). In addition, the possibility that iloprost, a drug commonly used in SSc therapy, might modulate the above-mentioned biological phenomena has been also investigated. In this regard, as compared to sera of SSc patients, sera of iloprost-treated SSc patients failed to increased ROS levels and collagen synthesis in HPMEC, suggesting a potential antioxidant mechanism of this drug.

A hydrogel containing exocellular (1 → 6)-β-D-glucan (lasiodiplodan, LAS) was developed and its wound healing potential was evaluated. β-Glucans have attracted much interest by the cosmetic industry sector because of their bioactive and functional properties and in promoting skin health. In the present work an β-glucan was studied as a healing biomaterial that has not hitherto been reported in the scientific literature. LAS produced by the ascomycete Lasiodiplodia theobromae MMPI was used in the formulation of a healing hydrogel. Physicochemical and microbiological quality parameters, antioxidant potential and stability of the formulation was evaluated. FTIR, thermal analysis and SEM techniques were also employed in the characterization. Wistar rats were used as a biological model to investigate the wound healing potential. Histological analyses of cutaneous tissue from the dorsal region were conducted after 4, 7, 10 and 14 days of treatment, and evaluated re-epithelialization, cell proliferation and collagen production. Physicochemical stability, microbiological quality and antioxidant potential, especially in relation to its ability to scavenge hydroxyl radicals were found. The hydrogel stimulated cell re-epithelialization and proliferation during all days of the treatment, and stimulated an increase of collagen fibers. Lasiodiplodan showed immunomodulatory activity in wound healing and this biomacromolecule could be an alternative compound in wound care., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Inhibiting myocardial fibrosis can help prevent cardiovascular diseases, including heart failure. Magnolol (Mag), a natural component of Magnoliae officinalis, has been reported to inhibit fibrosis. However, the mechanism of Mag activity and its effects on myocardial fibrosis remain unclear. Here, we investigated the involvement of ALDH2, an endogenous protective agent against myocardial fibrosis, in the Mag-mediated inhibition of cardiac fibroblast proliferation and collagen synthesis. We found that Mag significantly inhibited cardiac fibroblast proliferation and collagen synthesis, based on the results of MTT, EdU and western blot assays. Moreover, molecular docking, molecular dynamics simulation and surface plasmon resonance (SPR) assays showed that Mag could bind directly and stably to ALDH2. Further analysis of the mechanism of these effects indicated that treatment with Mag dose-dependently enhanced ALDH2 activity without altering protein expression. Mag could enhance the activity of recombinant human ALDH2 proteins with a half-maximal effective concentration of 5.79 × 10 -5 M. In addition, ALDH2 activation via Alda-1 inhibited cardiac fibroblast proliferation and collagen synthesis, while ALDH2 inhibition via daidzin partially blocked the suppressive effects of Mag. In summary, Mag may act as a natural ALDH2 agonist and inhibit cardiac fibroblast proliferation and collagen synthesis., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The development of safe and practical strategies to prevent weakening of bone tissue is vital, yet attempts to achieve this have been hindered by a lack of understanding of the short-term (days-weeks) physiology of bone collagen turnover. To address this, we have developed a method to quantify bone collagen synthesis in vivo, using deuterium oxide (D 2 O) tracer incorporation techniques combined with gas chromatography pyrolysis isotope-ratio mass spectrometry (GC-pyrolysis-IRMS). Forty-six male and female rats from a selectively bred model ingested D 2 O for 3 weeks. Femur diaphyses (FEM), tibia proximal (T-PRO), and distal (T-DIS) epiphyses-metaphyses and tibia mid-shaft diaphyses (T-MID) were obtained from all rats after necropsy. After demineralisation, collagen proteins were isolated and hydrolysed and collagen fractional synthetic rates (FSRs) determined by incorporation of deuterium into protein-bound alanine via GC-pyrolysis-IRMS. The collagen FSR for the FEM (0.131 ± 0.078%/day; 95% CI [0.106-0.156]) was greater than the FSR at T-MID (0.055 ± 0.049%/day; 95% CI [0.040-0.070]; p < 0.001). The T-PRO site had the highest FSR (0.203 ± 0.123%/day; 95% CI [0.166-0.241]) and T-DIS the lowest (0.027 ± 0.015%/day; 95% CI [0.022-0.031]). The three tibial sites exhibited different FSRs (p < 0.001). Herein, we have developed a sensitive method to quantify in vivo bone collagen synthesis and identified site-specific rates of synthesis, which could be applicable to studies of human bone collagen turnover., (© 2021 The Authors. Physiological Reports published by Wiley Periodicals LLC on behalf of The Physiological Society and the American Physiological Society.)

MicroRNAs (miRNAs) have been corroborated to engage in the process of cellular activities in osteoporosis. However, few researches have been conducted to expose the integrated role of miR-497, leucine-rich alpha-2-glycoprotein-1 (LRG1) and transforming growth factor beta 1 (TGF-β1)/Smads signalling pathway in osteoporosis. Thereafter, the study is set out to delve into miR-497/LRG1/TGF-β1/Smads signalling pathway axis in osteoporosis. Osteoporosis bone tissues and normal bone tissues were collected. Rat osteoporosis models were constructed via ovariectomy. Model rats were injected with restored miR-497 or depleted LRG1 to explore their roles in osteoporosis. Rat osteoblasts were extracted from osteoporosis rats and transfected with restored miR-497 or depleted LRG1 for further verification. MiR-497 and LRG1 expression in femoral head tissues and osteoblasts of osteoporosis rats were detected. TGF-β1/Smads signalling pathway-related factors were detected. MiR-497 was poorly expressed while LRG1 was highly expressed and TGF-β1/Smads signalling pathway activation was inhibited in osteoporosis. MiR-497 up-regulation or LRG1 down-regulation activated TGF-β1/Smads signalling pathway, promoted collagen type 1 synthesis and suppressed oxidative stress in femoral head tissues in osteoporosis. MiR-497 restoration or LRG1 knockdown activated TGF-β1/Smads signalling pathway, promoted viability and suppressed apoptosis of osteoblasts in osteoporosis. Our study suggests that miR-497 up-regulation or LRG1 down-regulation promotes osteoblast viability and collagen synthesis via activating TGF-β1/Smads signalling pathway, which may provide a novel reference for osteoporosis treatment., (© 2020 The Authors. Journal of Cellular and Molecular Medicine published by Foundation for Cellular and Molecular Medicine and John Wiley & Sons Ltd.)

The purpose of this study was to examine the effects of 12 weeks collagen peptide (CP) supplementation on knee pain and function in individuals with self-reported knee pain. Healthy physically active individuals ( n = 167; aged 63 [interquartile range = 56-68] years) with self-reported knee pain received 10 g/day of CP or placebo for 12 weeks. Knee pain and function were measured with the Visual Analog Scale (VAS), the Lysholm questionnaire, and the Knee injury and Osteoarthritis Outcome Score (KOOS). Furthermore, we assessed changes in inflammatory, cartilage, and bone (bio)markers. Measurements were conducted at baseline and after 12 weeks of supplementation. Baseline VAS did not differ between CP and placebo (4.7 [2.5-6.1] vs. 4.7 [2.8-6.2], p = 0.50), whereas a similar decrease in VAS was observed after supplementation (-1.6 ± 2.4 vs. -1.9 ± 2.6, p = 0.42). The KOOS and Lysholm scores increased after supplementation in both groups ( p values < 0.001), whereas the increase in the KOOS and Lysholm scores did not differ between groups ( p = 0.28 and p = 0.76, respectively). Furthermore, CP did not impact inflammatory, cartilage, and bone (bio)markers ( p values > 0.05). A reduced knee pain and improved knee function were observed following supplementation, but changes were similar between groups. This suggests that CP supplementation over a 12-week period does not reduce knee pain in healthy, active, middle-aged to elderly individuals. Novelty CP supplementation over a 12-week period does not reduce knee pain in healthy, active, middle-aged to elderly individuals. CP supplementation over a 12-week period does not impact on inflammatory, cartilage, and bone (bio)markers in healthy, active, middle-aged to elderly individuals.

The direct causes of idiopathic carpal tunnel syndrome (CTS) still remain obscure. It has been suggested that the pathology of tendons and other connective tissue structures within the carpal tunnel may be involved in its etiology. The objective of this study was to review the literature about the potential role of genetic factors in the etiology of CTS. Three different mechanisms are suspected to be involved in genetic predisposition to CTS: collagen synthesis, collagen degradation and protection against oxidative stress effect in connective tissue. Several gene groups are involved in the regulation and modulation of these mechanisms, and the research reviewed in this study showed their possible effect on the development of CTS. Variants within the COL1A1, COL5A1 and COL11A1 genes - encoding the synthesis of minor collagen subtypes - may potentially be involved, as they alter the mechanical properties of tendons and other connective tissue structures within the carpal tunnel. The collagen within connective tissue structures is also remodeled by matrix metalloproteinases (MMPs), so variants of these genes have also been investigated for their possible role in the risk of CTS development. Next, the variants of genes encoding glutathione S-transferase (GST) synthesis were found to be involved in the etiology of CTS. The findings from the abovementioned studies provide reliable information on the potential role of genetic risk factors in the development of CTS.

Background: Inguinal hernia disease is associated with an imbalanced collagen metabolism. Surgical stress has a negative impact on nutrients important for collagen synthesis., Objective: We hypothesized that supplementation with a combination of nutrients would enhance collagen biosynthesis in inguinal hernia disease patients when undergoing hernia repair., Methods: In this exploratory randomized controlled trial, 21 men (age: 55.2 ± 2.8 y; BMI: 25.0 ± 0.7 kg/m2) scheduled for Lichtenstein inguinal hernia repair were assigned to multinutrient supplementation (n = 10; multinutrient group) or no multinutrient supplementation (n = 11; control group). The multinutrient group received 14 g l-arginine, 14 g l-glutamine, 1250 mg vitamin C, and 55 mg zinc daily starting 14 d before surgery and ending 14 d after surgery. The multinutrient and control groups received high-quality protein to ensure a daily intake of 1.5 g protein/kg. Collagen biosynthesis was measured by the biomarkers type I procollagen propeptide (CICP), type III procollagen propeptide (PRO-C3), and type V procollagen propeptide (PRO-C5) in the sera on days -14, 0, and 1, and in the wound fluids on postoperative days 1 and 2. Compliance was recorded after the 28-d intervention period., Results: Serum PRO-C5 concentrations decreased (P < 0.05) postoperatively in the control but not the multinutrient group. Neither CICP nor PRO-C3 serum concentrations differed significantly between the 2 groups. In wound fluid, the CICP concentrations increased (P < 0.05) from days 1 to 2 in the multinutrient group and were 49% higher (P = 0.10) than those in the control group on day 2. Wound fluid concentrations PRO-C3 and PRO-C5 showed no significant time or group differences. The 28-d compliance was similar (P = 0.27) in the 2 groups., Conclusion: Oral supplementation with arginine, glutamine, vitamin C, and zinc augment collagen synthesis during the first 2 d after inguinal hernia repair. This trial was registered at clinicaltrials.gov as NCT03221686., (Copyright © The Author(s) 2020.)

Background: The dermis, composed predominantly of dermal fibroblasts and extracellular matrix (ECM), consists of fibrous proteins such as collagen and elastin and is associated with wrinkle formation and dermal elasticity. As the major constituent of the dermal matrix, collagen strengthens the skin, enhances its elasticity and protects it from external factors, such as ultraviolet (UV) rays, skin inflammation, intracellular metabolites, and aging., Aims: Economic growth and long-life expectancy have increased the interest in beauty, with extensive studies conducted to evaluate the anti-aging and health-promoting benefits of bioactive substances., Methods: In this study, we used natural ingredients, Trapa japonica fruit is a hard, aquatic plant that grows in ponds or marshes and contains protein and starch. To develop the ingredients for comprehensive skin improvement, this study investigated the effects of the trapa japonica fruit extract on the improvement of skin cells., Conclusion: We investigated the role of the fermented hot-water trapa japonica fruit extract to isolate the active ingredients with antiwrinkle effects in vitro and ex vivo situation through human dermal fibroblast cell proliferation via activating TGF-β1/GSK-3β/β-catenin pathway., (© 2020 Wiley Periodicals, Inc.)

Background/aim: The exploration of substances that stimulate collagen synthesis and retard the aging process of the skin is an active field of current research. The natural environment and plants used in traditional medicine have been a source of such substances. The aim of this study was to compare the stimulatory effect of betulin (BE), betulinic acid (BA) and the new derivative - betulin ester with diaminobutyl acid (BE-Dab-NH 2 ) on collagen synthesis in human normal fibroblasts., Materials and Methods: Primary fibroblast cultures were obtained from the gums of a healthy patient. The effect of the above-mentioned compounds was assessed by Sircol collagen assay, immunocytochemistry, and proliferation test., Results: Fibroblasts cultured in the presence of BE-Dab-NH 2 produced 6.85 times more collagen than control cells, 7.85 times more than those cultured in the presence of BA and 6.31 times more than those cultured in the presence of BE. An intense immunocytochemical reaction for collagen type I and III was found in fibroblasts cultured in the presence of BE-Dab-NH 2 Conclusion: BE-Dab-NH 2 stimulates significantly more collagen synthesis in normal human fibroblasts than its precursor., (Copyright© 2019, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Background: Cardiac remodelling is a dynamic process whereby structural and functional changes occur within the heart in response to injury or inflammation. Recent studies have demonstrated reactive oxygen species sensitive MAPK, apoptosis signal-regulating kinase 1 (ASK1) plays a critical role in cardiac remodelling. This study aims to determine the effectiveness of small molecule ASK1 inhibitors on these processes and their therapeutic potential., Methods: Neonatal rat cardiac fibroblasts (NCF) were pre-treated with ASK1 inhibitors, G2261818A (G226) and G2358939A (G235), for 2hours before stimulated with 100nM angiotensin II (AngII), 10μM indoxyl sulphate (IS) or 10ng/ml transforming growth factor β 1 (TGFβ 1 ) for 48hours. Neonatal rat cardiac myocytes (NCM) were pre-treated with G226 and G235 for 2hours before being stimulated with 100nM AngII for 60hours, 10μM IS, 10ng/ml interleukin 1β (IL-1β) or tumour necrosis factor α (TNFα) for 48hours. 3 H-proline and 3 H-leucine incorporation was used to assess collagen turnover and hypertrophy, respectively. Pro-fibrotic, pro-hypertrophic and THP-1 inflammatory cytokine gene expressions were determined by RT-PCR., Results: Both G226 and G235 dose-dependently attenuated AngII-, IS-, IL-1β- and TNFα-stimulated NCM hypertrophy and hypertrophic gene expression, IS-, AngII- and TGFβ 1 -stimulated NCF collagen synthesis and AngII- and TGFβ 1 -stimulated pro-fibrotic gene expression. Inhibition of ASK1 by G226 and G235 inhibited lipopolysaccharides-stimulated inflammatory cytokine gene expression in THP-1 cells., Conclusions: Selective ASK1 inhibition confers anti-hypertrophic and anti-fibrotic effects in cardiac cells, and anti-inflammation in monocytic cells. ASK1 inhibitors may represent novel therapeutic agents to alleviate cardiac remodelling post cardiac injury where hypertrophy, fibrosis and inflammation play critical roles., (Copyright © 2017 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.)

Aims: Keloids are a dermal fibrotic disease whose etiology remains totally unknown and for which there is no successful treatment. Mechanical tension, in addition, is closely associated with the germination and development of keloids. In this study, we investigated the influence of human keloid-derived mesenchymal stem cells (KD-MSCs) on cell proliferation, collagen synthesis, and expressions of integrin αvβ3 under tension., Main Methods: KD-MSCs and human normal skin-derived mesenchymal stem cells (NS-MSCs) were isolated and cultured in stem cell medium with a gradual increase in the serum concentration. Cell proliferation and collagen synthesis were detected by Cell Counting Kit-8 (CCK-8) assay and hydroxyproline content analysis under tension respectively. We investigated the messenger RNA expressions of nine integrin subunits, including integrin units α2, α3, α5, αv, α8, α10, α11, β1, and β3, in KD-MSCs stimulated with tension. Identification of differentially expressed genes was performed by Western blot analysis and immunocytochemistry staining., Key Findings: We obtained high-purity KD-MSCs and NS-MSCs using the culture method of decreasing serum concentration gradient gradually. Furthermore, we found that tension enhances cell proliferation and collagen synthesis and promotes expressions of integrin αvβ3 in KD-MSCs. In addition, blocking experiments showed that increased integrin αvβ3 expression affects cell proliferation and collagen synthesis of KD-MSCs under tension., Significance: Our results suggest that integrin αvβ3 receptor may be sensitive molecules of mechanical tension and could contribute to the occurrence and development of keloids. It could lead to novel targets for therapeutic intervention, treatment, and prevention of recurrence for keloid disorders., (Copyright © 2018. Published by Elsevier Inc.)

The skin consists mostly of extracellular matrix (ECM) composed mainly of collagen, which provides a protective barrier from the environment. The skin continuously experiences harmful stress and damage. As aging progresses, the expression of various genes declines, and physiological functional deterioration occurs. The reduction of collagen accompanying aging impairs the barrier function of the skin and weakens protection from stressors. In the nematode Caenorhabditis elegans, ECM proteins turn over during aging. Older worms of longevity mutants exhibit increased collagen expression, whereas knockdown of collagen genes shortens lifespan. However, it is unclear whether the progression of aging can be delayed by increasing collagen production via an external stimulus. In this study, we examined the effects of collagen tripeptide (CTP), a collagen-derived compound, on lifespan and aging. Our results showed that CTP upregulated collagen genes via the p38 mitogen-activated protein kinase (MAPK)/SKN-1 pathway. Moreover, CTP extended lifespan and delayed aging through p38 MAPK/SKN-1 pathway. In addition, CTP also induced collagen expression via the p38 MAPK pathway in mammals. Our findings supported that external stimuli such as CTP could promote ECM youthfulness using a conserved signaling pathway, thereby contributing to suppression of aging., (Copyright © 2018 Elsevier Inc. All rights reserved.)

The age-related reduction in the function of osteoblasts plays a central role in the pathogenesis of bone loss and osteoporosis. Collagen synthesis is a primary function of differentiated osteoblasts, however, the mechanisms for age-related changes in collagen synthesis in human osteoblasts remain elusive. We use Gene Ontology (GO) analysis and Gene Set Enrichment Analysis (GSEA) analysis to exploit the transcriptional profiles of osteoblasts from young and old donors. A panel of collagen members was downregulated in aged osteoblasts, including COL12A1, COL5A1, COL5A3, COL8A1 and COL8A2. Co-expression analysis followed by GO analysis revealed that oxidoreductase activity and kinase activity were inversely correlated with collagen synthesis in osteoblasts. GESA analysis further showed that JNK signaling was upregulated in aged osteoblasts. Consistently, MAP3K4 and MAP4K2, upstream of JNK, were also increased in aged osteoblasts. Moreover, expression levels of MAP3K4 were significantly inversely correlated with levels of the collagen genes. Those transcriptomic results were further verified by examining clinical specimens of osteoporosis by immunohistochemistry. These results provide transcriptomic evidence that deregulated JNK signaling may impair collagen synthesis in osteoblasts and imply a therapeutic value of JNK inhibitors for treating osteoporosis and preventing skeletal aging by counteracting the age-related reduction in the function of osteoblasts., (Copyright © 2018. Published by Elsevier Inc.)

Background and Aims: Collagen synthesis in vascular smooth muscle cells (VSMCs) is very important in atherosclerosis, as it affects plaque stability. In this study, we aim to assess whether miR-124-3p is involved in the collagen synthesis process in VSMCs and the role it might play in atherosclerotic development., Methods: We modulated the miR-124-3p expression in the aortic root plaques of high-fat-diet fed ApoE -/- mice by lentivirus injection. To determine plaque size and the content of plaque-stability-related cells or molecules, stainings, including hematoxylin and eosin, Oil red O, Sirius Red and immunohistochemical staining, were performed. Fluorescence in situ hybridization (FISH) was used to locate miR-124-3p in atherosclerotic plaques. Western blotting and RT-qPCR were carried out to determine the level of P4HA1 as well as type I and type III collagen protein and mRNA expression., Results: Results showed that collagen and VSMC content of plaques was inversely correlated with miR-124-3p levels. By FISH, we identified that miR-124-3p was primarily expressed by VSMCs. We also found that protein levels of type I and type III collagen in aortas and atherosclerotic plaques were decreased by miR-124-3p. We modulated miR-124-3p level in vitro and found it could inhibit collagen expression in HASMCs. This might be caused by the downregulation of P4HA1. P4HA1 was predicted as miR-124-3p's direct target, which was verified with a dual luciferase reporter assay and RIP test., Conclusions: The results presented here provide evidence that miR-124-3p inhibits VSMC collagen synthesis by directly targeting P4HA1, which might decrease atherosclerotic plaque stability., (Copyright © 2018. Published by Elsevier B.V.)

Tendons are essential weight-bearing structures that are often affected by tendinopathy, which leads to pain and impaired mobility. In healthy Achilles tendons, no significant renewal of the weight-bearing collagen matrix seems to occur during adult life, but tendinopathy may lead to increased turnover. The carbon-14 ([ 14 C]) bomb pulse method was used to measure lifelong replacement rates of collagen in tendinopathic and healthy Achilles tendons (tendinopathic: n = 25, born 1937-1972. Healthy: n = 10, born 1929-1966). As expected, the healthy tendon collagen had not been replaced during adulthood, but in tendinopathic tendon, a substantial renewal had occurred. Modeling of the [ 14 C] data suggested that one half of the collagen in tendinopathic matrix had undergone continuous slow turnover for years before the presentation of symptoms. This finding allows for a new concept in tendon pathogenesis because it suggests that either the symptoms of tendinopathy represent a late phase of a very prolonged disease process, or an abnormally high collagen exchange could be a risk factor for tendon disorders rather than being a result of disease.-Heinemeier, K. M., Schjerling, P., Øhlenschlæger, T. F., Eismark, C., Olsen, J., Kjær, M. Carbon-14 bomb pulse dating shows that tendinopathy is preceded by years of abnormally high collagen turnover.

Background/aims: Diabetes is associated with increased incidence of myocardial dysfunction, which is partly characterized by interstitial and perivascular fibrosis. Cardiac fibroblasts have been identified as an important participant in the development of cardiac fibrosis. Exposure of cultured cardiac fibroblasts to high glucose resulted in increased collagen synthesis. Tanshinone IIA can alleviate the ventricular fibrosis that develops in a number of different experimental conditions. However, whether tanshinone IIA can prevent high glucose-induced collagen synthesis in cardiac fibroblasts remains unknown. The aim of this study was to evaluate the effects of tanshinone IIA on high glucose-induced collagen synthesis in cardiac fibroblasts., Methods: Rat cardiac fibroblasts were cultured in high glucose (25 mM) media in the absence or presence of tanshinone IIA and the changes in collagen synthesis, transforming growth factor-β1 (TGF-β1) production and related signaling molecules were assessed by 3H-proline incorporation, quantitative polymerase chain reaction, enzyme linked immunosorbent assay, and Western blotting., Results: The results indicate cardiac fibroblasts exposed to high glucose condition show increased cell proliferation and collagen synthesis and these effects were abolished by tanshinone IIA treatment. Furthermore, the inhibitory effect of tanshinone IIA on high glucose induced cell proliferation and collagen synthesis may be associated with its activation of the nuclear factor erythroid 2-related factor 2 (Nrf2) and the inhibition of TGF-β1 production and Smad2/3 phosphorylation., Conclusion: In summary, our results highlights the critical role tanshinone IIA plays as an antioxidant in attenuating high glucose-mediated collagen synthesis through inhibiting TGF-β1/Smad signaling in cardiac fibroblasts which provide a mechanistic basis for the clinical application of tanshinone IIA in the treating diabetic-related cardiac fibrosis., (© 2018 The Author(s). Published by S. Karger AG, Basel.)

It has been reported that Dickkopf-3 (DKK3) down-regulation was examined in keloid fibroblasts, but the biological functions of DKK3 have not yet been investigated. In this study, we examined the expression of DKK3 in human keloid tissues, further evaluated the biological function of DKK3 and explored its potential molecular mechanism in transforming growth factor-β1 (TGF-β1)-induced keloid fibroblasts. Our results showed that DKK3 mRNA expression in human keloid tissues is down-regulated. DKK3 overexpression inhibited cell proliferation in TGF-β1-induced keloid fibroblasts transfected with pcDNA3.1-DKK3. Furthermore, DKK3 overexpression remarkably upregulated the protein expression levels of Bax and caspase-3, but decreased the protein expression of Bcl-2. In addition, DKK3 overexpression dramatically inhibited the protein and mRNA levels of collagen I (Col-I), collagen III (Col-III) and α-smooth muscle actin (α-SMA). Moreover, the protein expression of TGF-β receptor I (TGF-β RI), TGF-β receptor II (TGF-β RII), the phosphorylation of Smad2 (p-Smad2) and Smad3 (p-Smad3) was dramatically inhibited by pcDNA3.1-DKK3. LY2109761, a TGF-β receptor inhibitor, also suppressed cell proliferation, apoptosis and collagen synthesis in TGF-β1-induced keloid fibroblasts. Taken together, DKK3 overexpression could inhibit cell proliferation, induced cell apoptosis, and suppressed collagen synthesis through TGF-β1/Smad signaling in TGF-β1-induced keloid fibroblasts. Our findings suggest that DKK3 is a novel and promising molecular target for keloid treatment., (Copyright © 2017. Published by Elsevier Masson SAS.)

Injured anterior cruciate ligament (ACL) is hard to heal due to the poor proliferative potential of ACL fibroblasts. To verify whether mechano-growth factor (MGF) E peptide can restore the cell proliferation of injured ACL fibroblasts, ACL fibroblasts pretreated with MGF E peptide were subjected to injurious stretch and the outcomes were evaluated at 0 and 24 h. After injured, the type III collagen synthesis was increased at 0 h while inhibited at 24 h. The matrix metalloproteinase-2 (MMP-2) activity/expression was up-regulated, but the cell proliferation was inhibited. Fortunately, exogenous MGF E peptide decreased the type I/III collagen synthesis at 0 h but improved the type III collagen synthesis at 24 h. It decreased the MMP-2 activity/expression of injured ACL fibroblasts. Besides, MGF E peptide accelerated the cell proliferation via MEK-ERK1/2 signaling pathway. Our results implied that MGF E peptide pretreatment could provide a new efficient approach for ACL regeneration.

Background: The formation of intraarticular adhesion is a common complication after total knee arthroplasty or anterior cruciate ligament reconstruction. Previously, little research was reported regarding whether the local application of rapamycin (RAPA) could reduce intraarticular adhesion following knee surgery. In our present study, we determined the therapeutic effect of RAPA by local application on the reduction of intraarticular adhesion following knee surgery in rabbits., Methods: In this study, we built the model of knee surgery according to a previous study. The decorticated areas of the cortical bone were exposed and covered with cotton pads soaked with different concentrations of RAPA or physiological saline for 10 min. All of the rabbits were euthanized 4 weeks after the surgery. Macroscopic evaluation of the hydroxyproline content, the histological morphological analysis and collagen density and fibroblast density were used to evaluate the effect of RAPA on reducing intraarticular adhesion., Results: The results shown that RAPA could significantly inhibit the proliferation of fibroblasts and reduce collagen synthesis; in the rabbit model of knee surgery, there were weak scar tissues around the decorticated areas in the 0.2 mg/ml RAPA group; moderate scar tissues were found in the 0.1 mg/ml RAPA group. However, severe fibrous adhesions were found in the 0.05 mg/ml RAPA group and the control group. The hydroxyproline content and the fibroblast density in the 0.2 mg/ml and 0.1 mg/ml RAPA groups were significantly less than those of the control group., Conclusions: We concluded that the local application of RAPA could reduce intraarticular adhesion after knee surgery in the rabbit model; this effect was mediated by inhibition of fibroblast proliferation and collagen synthesis, which may provide a new method for reducing intraarticular adhesion after clinical knee surgery.

Aim: The objective of this study was to investigate the effects of urotensin II (UII) treatment on the proliferation and collagen synthesis of cultured rat pulmonary arterial smooth muscle cells (PASMCs) and to explore whether these effects are mediated by mitogen-activated protein kinase (MAPK) signaling pathways and early growth response 1 (Egr-1)., Methods: The proliferation of cultured PASMCs stimulated with different doses of UII was detected by BrdU incorporation. The mRNA expression levels of procollagen I (procol I), procollagen III (procol III), extracellular regulated protein kinase 1/2 (ERK1/2), stress-stimulated protein kinase (Sapk), p38 MAPK (p38), and Egr-1 mRNA in cultured PASMCs after treatment with UII, the UII-specific antagonist urantide, and the ERK1/2 inhibitor PD98059 were detected by real-time polymerase chain reaction (PCR), and the protein expression levels of procol I, procol III, phosphorylated (p)-ERK1/2, p-Sapk, p-p38, and Egr-1 were detected by Western blotting., Results: Treatment with UII increased the proliferation of cultured PASMCs in a dose-dependent manner (P<0.05). However, treatment with urantide and PD98059 inhibited the promoting effect of UII on PASMC proliferation (P<0.05). Real-time PCR analysis showed that UII up-regulated the expression of procol I, procol III, ERK1/2, Sapk, and Egr-1 mRNA (P<0.05), but not p38 mRNA. However, the up-regulating effect of UII was inhibited by PD98059 and urantide. Western blotting analysis showed that UII increased the synthesis of collagen I, collagen III, p-ERK1/2, p-Sapk, and Egr-1, and these effects also were inhibited by PD98059 and urantide (P<0.05)., Conclusions: Egr-1 participates in the UII-mediated proliferation and collagen synthesis of cultured rat PASMCs via activation of the ERK1/2 signaling pathway., (Copyright © 2015 Elsevier Inc. All rights reserved.)

In this study, tilapia skin collagen sponge and electrospun nanofibers were developed for wound dressing. The collagen sponge was composed of at least two α-peptides, and its denaturation temperature was 44.99 °C. It did not change the number of spleen-derived lymphocytes in BALB/c mice, the ratio of CD4+/CD8+ lymphocytes, and the level of IgG or IgM in Sprague-Dawley rat. The contact angle, tensile strength, and weight loss temperature of collagen nanofibers were 21.2°, 6.72±0.44 MPa, and 300 °C, respectively. The nanofibers could promote the viabilities of human keratinocytes (HaCaTs) and human dermal fibroblasts (HDFs), inducing epidermal differentiation through the gene expression of involucrin, filaggrin, and type I transglutaminase of HaCaTs, and they could also accelerate migration of HaCaTs with the expression of matrix metalloproteinase-9 and transforming growth factor-β1 (TGF-β1). Besides, the nanofibers could upregulate the protien level of Col-I in HDFs both via a direct effect and TGF-β1 secreted from HaCaTs, thus facilitating the formation of collagen fibers. Furthermore, the collagen nanofibers stimulated the skin regeneration rapidly and effectively in vivo. These biological effects could be explained as the contributions from the biomimic extracellular cell matrix structure, hydrophilicity, and the multiple amino acids of the collagen nanofibers.

Vascular endothelial growth factor (VEGF)-C is a key mediator of lymphangiogenesis. Our recent study shows that VEGF-C/VEGF receptors (VEGFR)-3 are significantly increased in the infarcted rat myocardium, where VEGFR-3 is expressed not only in lymph ducts but also in myofibroblasts, indicating that VEGF-C has an unrevealed role in fibrogenesis during cardiac repair. The current study is to explore the regulation and molecular mechanisms of VEGF-C in fibrogenesis. The potential regulation of VEGF-C on myofibroblast differentiation/growth/migration, collagen degradation/synthesis, and transforming growth factor (TGF)-β and ERK pathways was detected in cultured cardiac myofibroblasts. Our results showed that VEGF-C significantly increased myofibroblast proliferation, migration, and type I/III collagen production. Matrix metalloproteinase (MMP)-2 and -9 were significantly elevated in the medium of VEGF-C-treated cells, coincident with increased tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2. Furthermore, VEGF-C activated the TGF-β1 pathway and ERK phosphorylation, which was significantly suppressed by TGF-β or ERK blockade. This is the first study indicating that in addition to lymphangiogenesis, VEGF-C is also involved in fibrogenesis through stimulation of myofibroblast proliferation, migration, and collagen synthesis, via activation of the TGF-β1 and ERK pathways.

Regulation of collagen synthesis and matrix metalloproteinases (MMPs) expression levels has been an important issue in medicinal, pharmaceutical and cosmetic industries. Herein, α-Resorcylic acid-phenylalanine amide (α-RA-F) was prepared and its biological activities were observed. We found that α-RA-F boosted collagen synthesis and reduced MMPs expression levels in human fibroblasts without cytotoxicity., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Corneal fibroblasts maintain homeostasis of the corneal stroma by mediating the synthesis and degradation of extracellular collagen, and these actions are promoted by transforming growth factor-β (TGF-β) and interleukin-1β (IL-1β), respectively. The cornea is densely innervated with sensory nerve fibers that are not only responsible for sensation but also required for physiological processes such as tear secretion and wound healing. Loss or dysfunction of corneal nerves thus impairs corneal epithelial wound healing and can lead to neurotrophic keratopathy. The sensory neurotransmitter substance P (SP) promotes corneal epithelial wound healing by enhancing the stimulatory effects of growth factors and fibronectin. We have now investigated the role of SP in collagen metabolism mediated by human corneal fibroblasts in culture. Although SP alone had no effect on collagen synthesis or degradation by these cells, it promoted the stimulatory effect of TGF-β on collagen type I synthesis without affecting that of IL-1β on the expression of matrix metalloproteinase-1. This effect of SP on TGF-β-induced collagen synthesis was accompanied by activation of p38 mitogen-activated protein kinase (MAPK) signaling and was attenuated by pharmacological inhibition of p38 or of the neurokinin-1 receptor. Our results thus implicate SP as a modulator of TGF-β-induced collagen type I synthesis by human corneal fibroblasts, and they suggest that loss of this function may contribute to the development of neurotrophic keratopathy. NEW & NOTEWORTHY: This study investigates the role of substance P (SP) in collagen metabolism mediated by human corneal fibroblasts in culture. We found that, although SP alone had no effect on collagen synthesis or degradation by corneal fibroblasts, it promoted the stimulatory effect of transforming growth factor-β on collagen type I synthesis without affecting that of interleukin-1β on the expression of matrix metalloproteinase-1. [ABSTRACT FROM AUTHOR]

Background: Hyaluronic acid presents a valuable cosmetic ingredient that occurs naturally. Its direct links to skin aging has led to its broad application. The aim of this study was to improve the cosmetic efficacy of high molecular weight hyaluronic acid (HMWHA) without chemical modifications and evaluate such improvements through clinical and in vitro studies. Methods: A novel formulation of HMWHA (SCAI‐HA) was prepared and investigated to comparatively assess 6 clinical and 2 in vitro parameters concerning its dermatological cosmetic efficacy and biological properties. The dermatological and cellular parameters examined in this study include skin hydration, transepidermal water loss (TEWL), skin elasticity, wrinkles, facial sagging, dermal density, cytotoxicity, and collagen synthesis. Results: SCAI‐HA exhibited the ability to improve the tested dermatological parameters (hydration, elasticity, wrinkles, and density) to magnitudes comparable to those of HMWHA. In addition, SCAI‐HA showed notably improved capacities for attenuating facial sagging and TEWL and promoting cellular collagen synthesis in normal human dermal fibroblasts. Conclusion: SCAI‐HA presents a novel conformation of HMWHA with improved cosmetic efficacy in mitigating (i) facial sagging, (ii) TEWL, and promoting, and (iii) collagen synthesis. These findings denote the enhancement of SCAI‐HA as a cosmetic ingredient with potential anti‐aging properties. [ABSTRACT FROM AUTHOR]

This study relates to the Alteromonas ferment extract, a by-product of a marine bacteria, Alteromonas macleodii, is used in anti-aging cream formulation. Alteromonas ferment extract is an innovative anti-pollution ingredient that chelates heavy metals and has non-toxic anionic polysaccharides, which are used as thickening or structuring agent in tissue engineering, wound management or drug delivery applications. Aging is a physiological process, it is undesirable especially on the skin. Aging leads to weakening of facial muscles and loss of subcutaneous fat and skin laxity, along with wrinkles, prominent lines and sagging skin. Changes in collagen play an important role in reducing skin elasticity. In this case, fibroblast decreases, matrix metalloproteinase increases (responsible for collagen breakdown), and glycosaminoglycans decrease. The objective of the study was to evaluate effects of the anti-aging cosmetic face cream including Alteromonas ferment extract on human dermal fibroblast cells. The outcomes of the characterization analysis have indicated the development of a successful cream formulation with optimum characteristics. No microbial growth was observed. Given the results obtained in the tested conditions, the anti-aging cream is not cytotoxic against fibroblasts 0.5% or less concentration. The dilutions of 0.1% and 0.2% were chosen for evaluation of collagen concentration, because they were the most appropriate concentrations in terms of solubility and lack of cytotoxicity. The treatment with anti-aging cream formulation at 0.1% and 0.2% increased collagen synthesis 57% and 67%, respectively in cell culture. [ABSTRACT FROM AUTHOR]

Connective tissue growth factor (Ctgf) is a matricellular protein with diverse biological function. It is regarded as a central regulator of tissue fibrosis and collagen synthesis in mammals. However, its roles in fish remain elusive. Here, a ctgf gene was cloned (NcCtgf), characterized and functionally studied in the chu's croaker (Nibea coibor). NcCtgf encoded a protein containing 346 amino acids, 38 conserved cysteine residues, 4 functional domains and a signal peptide. NcCtgf shared highest identity (99.4 %) to the Larimichthys crocea Ctgf protein. Phylogenetic tree revealed that NcCtgf clustered with the teleost Ctgfa and Ctgf of higher vertebrates, instead of teleost Ctgfb. NcCtgf was expressed with higher level in gonad, spleen, gill and swimming bladder than other tissues, and was up-regulated in swim bladder synchronously with collagen I genes by hydroxyproline and TGF-β1 treatment. NcCtgf knockdown/overexpression inhibited/promoted collagen synthesis in swim bladder cell, respectively. Notably, NcCtgf protein could be secreted to cell culture medium and up-regulated collagen I expression in swim bladder cell. These findings indicate NcCtgf plays vital roles in collagen synthesis in swim bladder of Nibea coibor , and provide basis for further understanding of ctgf evolution and exploring new approach for enhancing collagen deposition in fish products during aquaculture. [ABSTRACT FROM AUTHOR]

Background: Nutrient regulation has been proven to be an effective way to improve the flesh quality in fish. As a necessary nutrient for fish growth, protein accounts for the highest proportion in the fish diet and is expensive. Although our team found that the effect of protein on the muscle hardness of grass carp was probably related to an increased collagen content, the mechanism for this effect has not been deeply explored. Moreover, few studies have explored the protein requirements of sub-adult grass crap (Ctenopharyngodon idella). Therefore, the effects of different dietary protein levels on the growth performance, nutritional value, muscle hardness, muscle fiber growth, collagen metabolism and related molecule expression in grass carp were investigated. Methods: A total of 450 healthy grass carp (721.16 ± 1.98 g) were selected and assigned randomly to six experimental groups with three replicates each (n = 25/replicate), and were fed six diets with 15.91%, 19.39%, 22.10%, 25.59%, 28.53% and 31.42% protein for 60 d. Results: Appropriate levels of dietary protein increased the feed intake, percentage weight gain, specific growth rate, body composition, unsaturated fatty acid content in muscle, partial free amino acid content in muscle, and muscle hardness of grass carp. These protein levels also increased the muscle fiber density, the frequency of new muscle fibers, the contents of collagen and IGF-1, and the enzyme activities of prolyl 4-hydroxylases and lysyloxidase, and decreased the activity of matrix metalloproteinase-2. At the molecular level, the optimal dietary protein increased collagen type I α1 (Colα1), Colα2, PI3K, Akt, S6K1, La ribonucleoprotein domain family member 6a (LARP6a), TGF-β1, Smad2, Smad4, Smad3, tissue inhibitor of metalloproteinase-2, MyoD, Myf5, MyoG and MyHC relative mRNA levels. The levels of the myostatin-1 and myostatin-2 genes were downregulated, and the protein expression levels of p-Smad2, Smad2, Smad4, p-Akt, Akt, LARP6 and Smad3 were increased. Conclusions: The appropriate levels of dietary protein promoted the growth of sub-adult grass carp and improved muscle hardness by promoting the growth of muscle fibers, improving collagen synthesis and depressing collagen degradation. In addition, the dietary protein requirements of sub-adult grass carp were 26.21% and 24.85% according to the quadratic regression analysis of growth performance (SGR) and the muscle hardness (collagen content), respectively. [ABSTRACT FROM AUTHOR]

Background: Salvianolic acid B (SAB) is one of the main active ingredients of Salvia Miltiorrhiza. It has significant skin anti‐aging, whitening, and sun protection properties. Aims: The study aimed at studying the mechanism underlying the effect of salvianolic acid Bon collagen synthesis, which has good anti‐aging efficacy and modulates microcirculation. Methods: This study employed available public databases, bioinformatics methodologies, and the inverse docking approach to explore the effectiveness of SAB in the regulating collagen synthesis, and then used an human dermal fibroblast (HDF)– Human dermal microvascular endothelial cell (HDMEC) in vitro model to validate the predicted mechanism of SAB in influencing collagen synthesis. Results: The results showed that NO production in SAB‐treated HDMEC‐conditioned medium was increased compared to that in control media, and the same tendency was also observed for growth factor production. SAB also upregulated HDMEC cellular eNOS and VEGF. When SAB‐treated HDMEC conditioned medium was transferred to HDFs, the expression of collagen I, collagen III, and elastin in HDFs was upregulated and MMP‐1 was downregulated. Conclusions: The results show that SAB regulates collagen through the HDMEC–HDF pathway. Furthermore, the mechanisms might be closely related to the microcirculation factors NO and VEGF. [ABSTRACT FROM AUTHOR]

An eight-week experiment was undertaken to examine the effect of dietary hydroxyproline (Hyp) supplementation on growth performance, collagen synthesis, muscle quality of an improved triploid crucian carp (Carassius auratus Triploid) (ITCC). Six isonitrogenous (340 g/kg diet), isolipidic (60 g/kg diet) and isocaloric (17.80 MJ/kg diet) diets were formulated containing a certain amount of Hyp: 0.09% (the control group), 0.39, 0.76, 1.14, 1.53 and 1.90%. Each diet was randomly assigned to three tanks and each group was fed two times daily until apparent satiation. The results showed that growth performance and feed utilization of ITCC were significantly improved with the dietary Hyp level was increased from 0.09 to 0.76%. Crude protein, threonine and arginine content in the dorsal muscle in 0.76% hydroxyproline group were significantly higher than those in basic diet group (p < 0.05). The muscle textural characteristics increased remarkably with the amount of Hyp in the diet rising from 0.09 to 1.53% (p < 0.05). Meanwhile, the contents of type I collagen (Col I) and Pyridinium crosslink (PYD) in the muscle of fish were significantly increased by dietary Hyp (p < 0.05). The muscle fiber diameter and density of the fish were significantly increased when fed with 0.76% Hyp (p < 0.05). Furthermore, dietary supplementation with an appropriate concentration of Hyp substantially increased the expression of genes involved in collagen synthesis (col1a1 , col1a2 , p4hα1 , p4hβ , smad4 , smad5 , smad9, and tgf-β) and muscle growth (igf-1 , tor , myod , myf5, and myhc) (p < 0.05). In conclusion, dietary supplementation of Hyp can enhance fish growth performance, collagen production, muscle textural characteristics and muscle growth of ITCC. According to the SGR broken-line analysis, the recommended supplementation level of Hyp was 0.74% in the diet for ITCC, corresponding to 2.2% of dietary protein. [ABSTRACT FROM AUTHOR]

[Display omitted] Tendon injuries typically display limited reparative capacity, often resulting in suboptimal outcomes and an elevated risk of recurrence or rupture. While cytokines of the IL-6 family are primarily recognised for their inflammatory properties, they also have multifaceted roles in tissue regeneration and repair. Despite this, studies examining the association between IL-6 family cytokines and tendon repair remained scarce. gp130, a type of glycoprotein, functions as a co-receptor for all cytokines in the IL-6 family. Its role is to assist in the transmission of signals following the binding of ligands to receptors. RCGD423 is a gp130 modulator. Phosphorylation of residue Y759 of gp130 recruits SHP2 and SOCS3 and inhibits activation of the STAT3 pathway. In our study, RCGD423 stimulated the formation of homologous dimers of gp130 and the phosphorylation of Y759 residues without the involvement of IL-6 and IL-6R. Subsequently, the phosphorylated residues recruited SHP2, activating the downstream ERK and AKT pathways. These mechanisms ultimately promoted the migration ability of tenocytes and matrix synthesis, especially collagen I. Moreover, RCGD423 also demonstrated significant improvements in collagen content, alignment of collagen fibres, and biological and biomechanical function in a rat Achilles tendon injury model. In summary, we demonstrated a promising gp130 modulator (RCGD423) that could potentially enhance tendon injury repair by redirecting downstream signalling of IL-6, suggesting its potential therapeutic application for tendon injuries. [ABSTRACT FROM AUTHOR]

Microencapsulation is an available and effective therapeutic option for entrapping targeted bioactive components. In this study, biomineralization-mediated separation and encapsulation of food-derived bioactive materials in organic materials were conducted, and the storage stability and effectiveness of these materials in the promotion of skin wound healing were assessed. To generate fine-textured and mechanically stable hexagonal particles, the hybrid materials were assembled using CaCO 3 mineralized with an amphiphilic copolymer coupled with curcumin (CUR). The synthesized products were characterized using field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and particle size analysis. The hybrid microparticles contained 1.58 wt% of CUR, and 91% of its initial concentration was retained after storage at four different temperatures. Based on the crystallization mechanism, CUR with an amphiphilic copolymer could be the core component that provides the surface for CaCO 3 crystal growth, causing independent formation of the organic–inorganic structures and preventing CUR leaching. Furthermore, the induced hybrid particles were found to promote skin wound healing by stimulating collagen synthesis without inducing cytotoxicity. To the best of our knowledge, this is the first study to demonstrate the potential use of bioactive ingredients with an amphiphilic copolymer combined with biomineralization for formulation purposes and to achieve a skin wound healing effect. [ABSTRACT FROM AUTHOR]

Chronic wounds including diabetic foot ulcers are clinical emergencies that need careful management. Exosomes from human adipose-derived mesenchymal stem cells (hADSCs-Ex) are a new promising cell-free therapy for the regeneration of dermal wounds. We established a delayed wound healing model using diabetic female mice. A 1.5 cm2 full-thickness cutaneous wound was made ventrally in 6-week-old db/db mice. After treatment with phosphate-buffered saline, recombinant human epidermal growth factor, hADSCs-CM, or hADSCs-Ex three times a day for 2 weeks, we measured wound healing closure rates and performed histological analysis. Human dermal fibroblasts (WS1) were evaluated by PKH26-Exo co-localization test, CCK-8 test, cell scratch test, and the transwell test, while the expression of matrix metalloproteinase-1 (MMP1), MMP3, Collagen I, and Collagen III were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR) and western blot. Wound closure and re-epithelialization were accelerated by hADSCs-Ex. Besides, hADSCs-Ex enhanced skin collagen production, angiogenesis, cell proliferation, inhibited apoptosis, promoted skin barrier function repair, and reduced inflammation in skin lesions. Furthermore, negative regulation of MMP1 and MMP3 enhanced collagen synthesis wound healing-promoting effects of hADSCs-Ex. hADSCs-Ex treatment for diabetic wounds provided a novel cell-free therapeutic strategy. [ABSTRACT FROM AUTHOR]

Background: Our previous research found that Q‐switched 1064‐nm Nd: YAG laser (1064‐QSNYL) induces skin collagen synthesis by activating TGFβ1/Smad3/p38MAPKs pathway. Moreover, a lot of studies shown that MicroRNAs (miRNAs) contribute to regulate collagen synthesis and skin barrier. Therefore, we intend to explore the mechanism of 1064‐QSNYL on collagen synthesis and skin barrier through miRNAs. Methods: We predicted the upstream miRNAs of TGFβ1 by bioinformatics databases, and verified them through dual‐luciferase reporter genes and Western blotting. The expression of collagen, skin barrier‐related protein K10 and filaggrin, TIMP‐1, and MMP‐2 were detected by RT‐qPCR and Western blotting, respectively. Moreover, we detected moisture content, elasticity value, TEWL value, SOD vitality, and hydroxyproline content to evaluate skin barrier of mice. H&E staining to observe the change of dermis thickness and inflammation and infiltration of mice skin. Results: The results shown that TGFβ1 was target gene of miR‐663a. Moreover, we found that 1064‐QSNYL activated TGFβ1/smad3/p38MAPK pathway by down‐regulating the expression of miR‐663a in HaCaT, HDF cells, and mice, thereby promoting expression of Collagen I, Collagen IV, TIMP‐1, K10, and filaggrin and inhibiting MMP‐2. Furthermore, 1064‐QSNYL contributed to moisture content, elasticity, SOD vitality, and hydroxyproline content via miR‐663a to activate TGFβ1/smad3/p38MAPK pathway. Conclusions: In summary, this study found for the first time that 1064‐QSNYL contributed to collagen synthesis and skin repair via miR‐663a to regulate TGFβ1/smad3/p38MAPK pathway, thereby achieving skin rejuvenation. [ABSTRACT FROM AUTHOR]

In the current research, a 60-d experiment was conducted with the purpose of exploring the impacts of methionine (Met) on growth performance, muscle nutritive deposition, muscle fibre growth and type I collagen synthesis as well as the related signalling pathway. Six diets (iso-nitrogenous) differing in Met concentrations (2·54, 4·85, 7·43, 10·12, 12·40 and 15·11 g/kg diets) were fed to 540 grass carp (178·47 (SD 0·36) g). Results showed (P < 0·05) that compared with Met deficiency, optimal level of dietary Met (1) increased feed intake, feed efficiency, specific growth rate and percentage weight gain (PWG); (2) increased fish muscle protein, lipid and free amino acid contents and improved fish muscle fatty acid profile as well as increased protein content in part associated with the target of rapamycin complex 1 (TORC1)/S6K1 signalling pathway; (3) increased the frequency distribution of muscle fibre with >50 µm of diameter; (4) increased type I collagen synthesis partly related to the transforming growth factor-β1/Smads and CK2/TORC1 signalling pathways. In conclusion, dietary Met improved muscle growth, which might be due to the regulation of muscle nutritive deposition, muscle fibre growth and type I collagen synthesis-related signal molecules. Finally, according to PWG and muscle collagen content, the Met requirements for on-growing grass carp (178–626 g) were estimated to be 9·56 g/kg diet (33·26 g/kg protein of diet) and 9·28 g/kg diet (32·29 g/kg of dietary protein), respectively. [ABSTRACT FROM AUTHOR]

One major goal in tissue engineering is to create functional materials, mimicking scaffolds in native tissues, to modulate cell function for tissue repair. Collagen is the most abundant structural protein in human body. Though collagen I (COLI) and collagen III (COLIII) are the predominant collagen types in connective tissues and they form stable hybrid fibrils at varied ratios, cell responses to the hybrid matrices are underinvestigated. In this work, we aim to explicate the distinctive roles of COLI and COLIII in fibroblast activation. Unidirectionally aligned COLI, COLIII and COLI-COLIII hybrid nanofibrils were generated via epitaxial growth of collagen on mica. AFM analyses revealed that, with the increase of COLI/COLIII ratio, the fibril width and stiffness increased and the binding affinity of cells to the matrix decreased. A hybrid matrix was found to activate fibroblasts the most effectively, characterized by extensive cell polarization with rigid stress fiber bundles and high α-SMA expression, and by the highest-level of collagen synthesis. It is ascribed to the fine balance between biochemical and biophysical cues achieved on the hybrid matrix. Thus, matrices of aligned COLI-COLIII hybrid fibrils and their derived multifunctional composites can be good candidates of implantation scaffolds for tissue regeneration. • Collagen I and collagen III have distinctive roles in fibroblast activation. • Unidirectionally aligned collagen nano-fibrils prompted cell polarization. • The stiffer COLI fibrils exert a higher force to cells. • α1β1-integrin binds stronger to COLIII than to COLI. • COLI-COLIII hybrid fibrils promoted collagen synthesis the most effectively. [ABSTRACT FROM AUTHOR]

Background: Protocatechuic acid has reported containing antioxidant effects. However, information on its other biological activities such as anti‐wrinkle properties is limited Aims: The objective of this study was to evaluate an antioxidant, collagen synthesis, MMP‐1 inhibition (in vitro), and anti‐wrinkle (in vivo) effects of protocatechuic acid (PCA) as a potent ingredient for wrinkle‐care cosmetic. Methods: Antioxidant effect was evaluated based on its scavenging activity for free radicals (DPPH, ABTS+). To evaluate the anti‐skin aging potency of PCA, levels of MMP‐1 and type I procollagen were measured using an ELISA kit in cultured human dermal fibroblasts. To further investigate if PCA could increase collagen synthesis, full‐thickness human skin explants were immunostained with an anti‐collagen I antibody. In an in vivo study, 22 female subjects were enrolled in a placebo‐controlled trial. Facial wrinkle, especially crow's feet around eyes, was treated with lotion‐containing 0.02% PCA for 8 weeks and compared with the placebo. Results: In in vitro study, PCA showed high antioxidant activ ity. PCA also showed potential to induce the synthesis of type I collagen in human dermal fibroblast and skin explants. It inhibited MMP‐1 secretion from UVA‐irradiated human dermal fibroblast. An in vivo study, treatment with lotion‐containing 0.02% PCA for 8 weeks significantly reduced the percentage of all skin wrinkle parameters. Conclusion: Based on the results of in vitro assays and in vivo skin testing in human subjects, PCA shows potential in anti‐wrinkle or anti‐skin aging treatments. [ABSTRACT FROM AUTHOR]

Hydroxyproline (Hyp) may play an important role in collagen metabolism, as it is almost exclusively found in collagen. To examine this possibility, a 56‐day feeding trial was conducted to evaluate the effect of graded supplementaries of Hyp (0, 2.5, 5, 7.5, 10 and 12.5 g/kg dry diet weight) on growth performance, feed utilization, biochemical composition and collagen synthesis of chu's croaker, Nibea coibor (13.6 ± 0.28 g). The growth performance and feed utilization were improved with increased levels of dietary Hyp, reaching a maximum at 5 g/kg (diet H2) followed by a slight decrease. Polynomial regression analysis showed that the maximum specific growth rate (SGR) was attained at 7.177 g/kg dietary Hyp. Increasing levels of Hyp did not affect body composition of juvenile Nibea coibor. However, dietary Hyp supplementation significantly affected the levels of Leu, Ile, Met, Lys, Ser, Glu and Pro in muscle and the levels of Met, Lys, Glu, Pro and Gly in swim bladder. The serum calcium (SC) level decreased significantly with increasing levels of dietary Hyp. However, the triglycerides (TG) and total cholesterol (T‐CH) levels in serum and liver were relatively stable. Importantly, the acid‐soluble collagen (ASC) and total collagen (TC) levels in swim bladder increased significantly initially and then decreased after reaching a maximum. Polynomial regression analysis revealed that the maximum TC level in swim bladder was attained at 9.736 g/kg of dietary Hyp. Collectively, these results suggest that the appropriate provision of hydroxyproline is essential for maximal collagen synthesis and growth. [ABSTRACT FROM AUTHOR]

Objectives: We aimed to investigate the effects of icariside II (ICS II) on myocardial fibrosis in spontaneously hypertensive rats (SHRs) and to explore the possible mechanisms. Methods: We used SHRs as animal models, and we administered ICS II (4, 8 or 16 mg/kg) orally by gavage for 12 consecutive weeks (Fu et al., Biomed Pharmacother 2018; 100: 64). The left ventricular morphology of the rats was observed using haematoxylin–eosin (HE) staining. The occurrence of myocardial interstitial fibrosis was detected by Masson's trichrome staining. The protein levels of alpha smooth muscle actin (α‐SMA), Collagen I, III, matrix metalloproteinases 2 and 9 (MMP‐2 and MMP‐9, respectively), tissue inhibitor of metalloproteinase 1 (TIMP‐1), transforming growth factor‐β1 (TGF‐β1), phospho‐Smad2 (p‐Smad2), phospho‐Smad3 (p‐Smad3) and phospho‐p38 (p‐p38) were examined by Western blotting. Key findings: The results suggested that ICS II improved myocardial interstitial and perivascular collagen deposition and decreased Collagen I/III and α‐SMA expression. ICS II (8 and 16 mg/kg) downregulated the expression of MMP‐2 and MMP9 and upregulated the expression of TIMP1. In addition, the protein levels of p‐Smad2/3, TGF‐β1 and p‐p38 were decreased by ICS II treatment. Conclusions: The results suggest that ICS II can inhibit the expression of Collagen I and Collagen III through the MMP/TIMP‐1 and TGF‐β1/Smad2,3/p‐p38 signalling pathways and that it has therapeutic effects on myocardial fibrosis. [ABSTRACT FROM AUTHOR]

Autologous split thickness skin graft is necessary for the survival of patients with large burns and skin defects. It is not clear how a thin split thickness skin graft becomes remarkably thicker within a few weeks following transplantation. Here, we hypothesized that growth of split thickness graft should be from bottom up probably through conversion of immune cells into collagen producing skin cells. We tested this hypothesis in a preclinical porcine model by grafting split thickness meshed skin (0.508 mm thickness, meshed at 3:1 ratio) on full thickness wounds in pigs. New tissue formation was evaluated on days 10 and 20 postoperation through histological analysis and co-staining for immune cell markers (CD45) and type I collagen. The findings revealed that a split thickness graft grew from bottom up and reached to almost the same level as uninjured skin within 60 days postoperation. The result of immune-staining identified a large number of cells, which co-expressed immune cell marker (CD45) and collagen on day 10 postoperation. Interestingly, as the number of these cells reduced on day 20, most of these cells became positive for collagen production. In another set of experiments, we tested whether immune cells can convert to collagen producing cells in vitro. The results showed that mouse adherent immune cells started to express type 1 procollagen and α-smooth muscle actin when cultured in the presence of fibroblast conditioned media. In conclusion, the early thickening of split thickness graft is likely happening through a major contribution of infiltrated immune cells that convert into mainly collagen producing fibroblasts in large skin injuries. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effect of microRNA-152 (miR-152)-targeted angiotensin receptor (AT1R) on angiotensin II (Angll)-induced rat cardiac fibroblast proliferation and collagen synthesis. Methods: Rat cardiac fibroblasts were cultured in vitro and stimulated with 1 μmoI/L Align. The proliferation of fibroblast was detected by MTT assay, the expression of collagen I (Collagen I), collagen I (Collagen El) and AT1R protein in the fibroblasts were detected by western blotting, real-time quantitative polymerase chain reaction (qRT-PC'R) was performed to detect the expression of miR-152 and AT1R mRNA in the fibroblasts. MiR-152 mimic and mimic control. AT1R siRNA and siRNA control were transfected and co-transfected with miR-152 mimic and AT1R overexpression vectors in AngH-induced cardiac fibroblasts, respectively, the cell proliferation and collagen synthesis were detected in the same manner. The dual luciferase reporter gene assay was used to detect the targeted binding relationship of miR-152 and AT1R. Results: AngE stimulation can promote the proliferation of cardiac fibroblasts, up-regulate the expression of collagen Collagen I and Collagen El in the fibroblasts, and inhibit the expression of miR-152 and promote the expression of ATIR mRNA and protein. Overexpression of miR-152 or silencing AT1R in AngE-induced cardiac fibroblasts can upregulate cell proliferation and promote collagen synthesis. The results of the dual luciferase reporter gene assay showed that AT1R is a miR-152 target gene, and miR-152 can negatively regulate the expression of ATI R. Simultaneous overexpression of miR-152 and AT1R in AngE-induced cardiac fibroblasts can reverse the inhibition of cell proliferation induced by overexpression of miR-152 alone, and up-regulate the inhibition of collagen Collagen I and Collagen El synthesis. Conclusion: miR-152 can inhibit the proliferation and collagen synthesis of cardiac fibroblasts induced by AngE. and its mechanism may be related to target the expression of ATI R. [ABSTRACT FROM AUTHOR]

Large joint arthrofibrosis and scarring, involving the shoulder, elbow, hip, and knee, can result in the loss of function and immobility. The pathway of joint contracture formation is still being elucidated and is due to aberrations in collagen synthesis and misorientation of collagen fibrils. Novel antibodies are being developed to prevent arthrofibrosis, and current treatment methods for arthrofibrosis include medical, physical, and surgical treatments. This article describes the biology of joint contracture formation, along with current and future pharmacologic, biologic, and medical interventions. [ABSTRACT FROM AUTHOR]

Adipose-derived stem cells (ASCs) have been shown to enhance wound healing by human dermal fibroblasts; however, the interactions between ASCs and fibroblasts during injury remain unclear. Fibroblasts were treated with ASC-conditioned medium (ASC-CM) with and without transforming growth factor-β1 (TGF-β1) stimulation. Fibroblast proliferation, apoptosis, differentiation and expression of extracellular matrix genes and proteins, type I collagen, and type III collagen were measured. Also, wound-healing effect of ASC-CM was verified with in vivo animal study. ASC-CM inhibited proliferation and enhanced apoptosis of fibroblasts under TGF-β1 stimulation. Furthermore, 10% ASC-CM inhibited α-smooth muscle actin expression in fibroblasts, whereas 100% ASC-CM increased collagen, especially type III, expression in fibroblasts. ASC-CM was found to contain more basic fibroblast growth factor than hepatocyte growth factor, and 100% ASC-CM increased hepatocyte growth factor gene expression in fibroblasts. These results suggest ASCs affect fibrogenesis by dermal fibroblasts stimulated with TGF-β1 via paracrine signaling by adipocytokines present in ASC-CM. These results also suggest that higher concentrations of ASC-CM increase collagen production and inhibit fibroblast proliferation to avoid excessive fibrogenesis. We demonstrated that a lower ASC-CM concentration attenuated fibroblast differentiation. Additionally, 100% ASC-CM significantly reduced the wound size in an in vivo wound-healing model. In this study, we provided evidence that ASCs modulate fibrogenesis by fibroblasts via paracrine signaling, suggesting that application of ASCs during wound healing may improve the quality of wound repair. [ABSTRACT FROM AUTHOR]