Decreased Collagen Production Research Articles

Inhibition of penile tunica albuginea myofibroblasts activity by adipose-derived stem cells.

The activation of tunica albuginea myofibroblasts (MFs) serves an essential role in Peyronie's disease (PD). Increasing evidence has reported that adipose tissue-derived stem cells (ADSCs) have been demonstrated to attenuate the symptoms of PD in animal models. However, the mechanisms of the antifibrotic effects of ADSCs in PD remain to be fully elucidated. In the present study, the inhibitory effects and possible mechanism of ADSCs on the activation of MFs derived from rat penile tunica albuginea were investigated. ADSCs were obtained from the paratesticular fat of Sprague Dawley rats. MFs were transformed from rat penile tunica albuginea fibroblasts through stimulation with 5 ng/ml tumor growth factor-β1. Transwell cell cultures were adopted for co-culture of ADSCs and MFs. Western blot analysis was used to assess changes in the expression levels of α smooth muscle actin (αSMA), collagen I, phosphorylated (p)-SMAD family member 2 (Smad2), Smad2, ras homolog family member A (RhoA), Rho associated coiled-coil containing protein kinase (ROCK)1 and ROCK2, caspase3, caspase9, and matrix metalloproteinases (MMPs). Collagen gel assays were used to assess cell contractility. Additionally, the concentration of hydroxyproline in the culture medium was detected using commercially available kits. It was demonstrated that ADSCs reduced the expression of αSMA and collagen I of MFs. Furthermore, p-Smad2, RhoA, ROCK1 and ROCK2 expression was significantly reduced in the MFs+ADSCs group compared with that in the MFs-only culture, while the expression of MMPs (MMP2, MMP3, MMP9 and MMP13) and caspases (caspase3 and caspase9) was upregulated. In addition, ADSCs were able to downregulate the concentration of hydroxyproline in the culture medium of MFs and reverse the contraction of MFs. Collectively, these results suggested that ADSCs inhibited the activation of MFs, decreased collagen production, and suppressed the contraction of myofibroblasts, via Smad and RhoA/ROCK signaling pathways. Furthermore, ADSCs reduced the deposition of collagen and promoted the apoptosis of MFs via MMPs, and caspases. Accordingly, the application of ADSCs may provide a novel therapeutic strategy for PD.

Abstract 1679: BET inhibitors suppress PD-L1 expression in pancreatic stellate cells

Abstract Single agent treatment with T-cell checkpoint inhibitors has not been effective in pancreatic ductal adenocarcinoma (PDAC) patients. The PDAC stroma, which can account for as much as 80-90% of the tumor mass, can act as a physical and an immunologic barrier to T-cell-mediated therapies. Transgenic mouse models have shown that ablation of pancreatic stellate cells (PSCs), key regulators of fibrosis in vivo, can sensitize PDAC tumors to immune checkpoint therapies. Recently, inhibitors targeting bromodomains and extra-terminal (BET) proteins, a number of which are currently being evaluated in clinical trials for solid tumors, were shown to induce stellate cells to become quiescent and decrease collagen production. The BET family of proteins binds to acetylation motifs present in histones and enables recruitment of transcription factors and other chromatin regulators during RNA transcription. We have found that PSCs express significantly increased PD-L1 levels compared to pancreatic cancer cell lines. We show that BET inhibitors, and in particular specific knockdown of BRD4 protein, decrease basal and IFN-γ-mediated PD-L1 expression in primary stellate cells. We also show that, in contrast to a recent report using cancer cells, c-MYC does not mediate basal or IFN-γ-mediated PD-L1 expression in stellate cells. Instead, we show that the IFN-γ-mediated PD-L1 expression is regulated by IRF1, suggesting cross talk between BRD4 and IRF1 in the regulation of PD-L1 expression. Ongoing in vivo experiments will evaluate the role of BET inhibitors in the regulation of PD-L1 in mouse models of pancreatic cancer. Citation Format: Kazumi Ebine, Brian T. DeCant, Katharine A. Collier, Thao N. Pham, Krishan Kumar, Hidayatullah G. Munshi. BET inhibitors suppress PD-L1 expression in pancreatic stellate cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1679. doi:10.1158/1538-7445.AM2017-1679

Impaired collagen synthesis in the rectum may be a molecular target in anastomotic leakage prophylaxis.

The underlying molecular mechanisms for anastomotic leakage (AL) after colorectal surgery are unknown and there are no therapeutics for AL prevention. Our aim was to correlate endogenous matrix metalloproteinase (MMP) activity, collagen concentration, and collagen/MMP/cytokine mRNA levels with anatomic location in human colorectal tissue. We enrolled 22 patients in this prospective study: 7 underwent elective laparoscopic sigmoid resection and 15 underwent low anterior resection for colorectal cancer. Full-thickness intestinal tissue rings from anastomoses constructed with a circular stapler were used for the determination of the MMP activity, tissue collagen concentration and mRNA levels. COL1A1 (p = 0.017) and COL3A1 (p = 0.0013) mRNA levels were lower in rectal tissue than in colonic samples. Neither MMP activities nor collagen concentrations differed significantly between the two anatomic locations. By elucidating the factors responsible for the decreased collagen production we may identify specific molecular targets in AL prophylaxis.

Methylparaben-induced decrease in collagen production and viability of cultured human dermal fibroblasts.

Parabens owing to their many advantageous properties are widely applied in cosmetics, food products and pharmaceuticals. However, recent research results have shown that they possess the ability to accumulate in the human body and exert many adverse effects. In this study, the impact of methylparaben (MP) as the most frequently used preservative in cosmetics, on human dermal fibroblasts and collagen production was evaluated. In cells treated with 0.01, 0.03 and 0.05% MP a dose-dependent decrease in collagen biosynthesis was revealed, which was positively correlated with the activity of prolidase responsible for the recovery of proline. Consequently, the concentration of total collagen secreted into the medium was markedly diminished. A similar reduction in expression of the major skin collagen type I at both the protein and mRNA level as well as collagen type III and VI at the mRNA level was also detected. The decrease in the collagen level may result not only from the reduced synthesis but also increased degradation owing to MP-induced activation of pro-MMP-2 (72 kDa). The increase in activity of MMP-2 (66 kDa) was accompanied by a reduction in the inhibitory activity of TIMP-2. In addition, an inhibitory effect of MP on cell survival and proliferation was revealed in this study. The increased expression and nuclear translocation of caspase-3 as well as increased Bax and decreased Bcl-2 expression may suggest MP-induced cell apoptosis. In summary, we have provided new data on the adverse effects of methylparaben on human dermal fibroblasts and the main structural protein of the skin. Further studies on the mechanisms responsible for its action are in progress. Copyright © 2017 John Wiley & Sons, Ltd.

Platelets in liver disease, cancer and regeneration.

Although viral hepatitis treatments have evolved over the years, the resultant liver cirrhosis still does not completely heal. Platelets contain proteins required for hemostasis, as well as many growth factors required for organ development, tissue regeneration and repair. Thrombocytopenia, which is frequently observed in patients with chronic liver disease (CLD) and cirrhosis, can manifest from decreased thrombopoietin production and accelerated platelet destruction caused by hypersplenism; however, the relationship between thrombocytopenia and hepatic pathogenesis, as well as the role of platelets in CLD, is poorly understood. In this paper, experimental evidence of platelets improving liver fibrosis and accelerating liver regeneration is summarized and addressed based on studies conducted in our laboratory and current progress reports from other investigators. In addition, we describe our current perspective based on the results of these studies. Platelets improve liver fibrosis by inactivating hepatic stellate cells, which decreases collagen production. The regenerative effect of platelets in the liver involves a direct effect on hepatocytes, a cooperative effect with liver sinusoidal endothelial cells, and a collaborative effect with Kupffer cells. Based on these observations, we ascertained the direct effect of platelet transfusion on improving several indicators of liver function in patients with CLD and liver cirrhosis. However, unlike the results of our previous clinical study, the smaller incremental changes in liver function in patients with CLD who received eltrombopag for 6 mo were due to patient selection from a heterogeneous population. We highlight the current knowledge concerning the role of platelets in CLD and cancer and anticipate a novel application of platelet-based clinical therapies to treat liver disease.

Abstract B17: BET inhibitors block pancreatic stellate cell collagen production and attenuate fibrosis in vivo

Abstract The fibrotic reaction, which can account for over 70% of the tumor mass, is a characteristic feature of the majority of human pancreatic ductal adenocarcinoma (PDAC) tumors. It is associated with proliferation of pancreatic stellate cells (PSCs), which are key regulators of collagen production and fibrosis in vivo. In this report we show that bromodomain-containing protein 4 (BRD4), a member of bromodomain and extraterminal (BET) family of proteins, is expressed in activated PSCs in human PDAC tumors. We also show that BET inhibitors and specific targeting of BRD4, in contrast to targeting of BRD2 and BRD3, decrease collagen production by primary PSCs isolated from human PDAC tumors. While BET inhibitors do not induce apoptosis of primary PSCs or affect α-SMA expression, BET inhibitors disrupt α-SMA filament organization in stellate cells. Additionally, BET inhibitors attenuate stellate cell activation, fibrosis and collagen production in vivo in a Kras mouse model of pancreatic tumorigenesis. Our results demonstrate that BET inhibitors regulate fibrosis partly by modulating PSC activation and function. Citation Format: Krishan Kumar, Brian DeCant, Hattaway Z. Hattaway, Paul J. Grippo, David J. Bentrem, Kazumi Ebine, Hidayatullah G. Munshi.{Authors}. BET inhibitors block pancreatic stellate cell collagen production and attenuate fibrosis in vivo. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2016 May 12-15; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2016;76(24 Suppl):Abstract nr B17.

Prostaglandin E2 inhibits collagen synthesis in dermal fibroblasts and prevents hypertrophic scar formation in vivo.

Hypertrophic scarring is a common dermal fibroproliferative disorder characterized by excessive collagen deposition. Prostaglandin E2 (PGE2 ), an important inflammatory product synthesized via the arachidonic acid cascade, has been shown to act as a fibroblast modulator and to possess antifibroblastic activity. However, the mechanism underlying the antifibrotic effect of PGE2 remains unclear. In this study, we explored the effects of PGE2 on TGF-β1-treated dermal fibroblasts in terms of collagen production and to determine the regulatory pathways involved, as well as understand the antiscarring function of PGE2 in vivo. We found that PGE2 inhibited TGF-β1-induced collagen synthesis by regulating the balance of matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinase (TIMP). It did so by upregulating cAMP through the E prostanoid (EP)2 receptor. We determined that inhibition of the TGF-β1/Smad pathway by PGE2 is associated with its ability to inhibit collagen synthesis. An in vivo study further confirmed that PGE2 inhibits hypertrophic scar formation by decreasing collagen production. Our results demonstrate that the novel anti-scarring function of PGE2 is achieved by balancing MMPs/TIMP expression and decreasing collagen production.

Human amniotic epithelial cells attenuate TGF-β1-induced human dermal fibroblast transformation to myofibroblasts via TGF-β1/Smad3 pathway

Background aimsKeloids are raised dermal scars that extend beyond the boundaries of the initial injury. To date, there is no treatment to erase scars completely in humans. Growing evidence has shown that the human amniotic epithelial cells have anti-fibrotic properties and can reduce the fibrosis of lung and liver. However, it is unknown whether and how they can influence human keloids. The aim of this study was to investigate whether factors secreted by human amniotic epithelial cells have anti-fibrotic effects on human keloids and to clarify the potential transduction mechanism. MethodsHuman amniotic epithelial cells were isolated and identified both with flow cytometry and immunofluorescent. The α-smooth muscle actin, collagen-I and III gene and protein expression of transforming growth factor (TGF)-β1-treated human adult dermal fibroblasts were partly abolished by human amniotic epithelial cells conditioned medium through stimulating the expression of matrix metalloproteinase (MMP). Furthermore, human amniotic epithelial cells conditioned medium effectively attenuated nuclear import of the Smad2/3 complex. ResultsSoluble human leukocyte antigen G, a human amniotic epithelial cell–derived factor, significantly decreased collagen production in TGF-β1–induced human dermal fibroblasts, although the effect on collagen production was less than that of human amniotic epithelial cell–conditioned medium. ConclusionsThis study demonstrates that human amniotic epithelial cells conditioned medium could down-regulate the expression of fibrosis-related molecules by regulating MMP and tissue inhibitor of metalloproteinase levels, and suppress TGF-β1–induced fibroblast transition, in which the TGF-β1/Smad3 pathway is likely involved. These findings suggest that human amniotic epithelial cells are a potential therapeutic compound for the treatment of keloids.

Novel functions of platelets in the liver.

Platelets contain not only proteins needed for hemostasis but also many growth factors that are required for organ development, tissue regeneration, and repair. Thrombocytopenia, which is frequently observed in patients with chronic liver disease (CLD) and cirrhosis, is due to various causes, such as decreased thrombopoietin production and accelerated platelet destruction caused by hypersplenism; however, the relationship between thrombocytopenia and hepatic pathogenesis and the role of platelets in CLD are poorly understood. Thus, in this paper, the experimental evidence for platelets improving liver fibrosis and accelerating liver regeneration is summarized and addressed based on studies conducted in our laboratory and current progress reports from other investigators. Platelets improve liver fibrosis by inactivating hepatic stellate cells to decrease collagen production. The level of intracellular cAMP is increased by adenosine through its receptors on hepatic stellate cells, thereby resulting in inactivation of these cells. Adenosine is produced by degradation of adenine nucleotides, which are stored in abundance within the dense granules of platelets. The regenerative effect of platelets in the liver consists of three mechanisms: a direct effect on hepatocytes, a cooperative effect with liver sinusoidal endothelial cells, and a collaborative effect with Kupffer cells. Based on these experiments, a clinical trial suggested that the increase in platelets induced by platelet transfusion improved liver function in patients with CLD in a clinical setting.We highlight the current knowledge concerning the role of platelets in CLD and expect to open a novel avenue for application of these clinical therapies to treat liver disease.

Bee Venom Accelerates Wound Healing in Diabetic Mice by Suppressing Activating Transcription Factor‐3 (ATF‐3) and Inducible Nitric Oxide Synthase (iNOS)‐Mediated Oxidative Stress and Recruiting Bone Marrow‐Derived Endothelial Progenitor Cells

Multiple mechanisms contribute to impaired diabetic wound healing including impaired neovascularization and deficient endothelial progenitor cell (EPC) recruitment. Bee venom (BV) has been used as an anti-inflammatory agent for the treatment of several diseases. Nevertheless, the effect of BV on the healing of diabetic wounds has not been studied. Therefore, in this study, we investigated the impact of BV on diabetic wound closure in a type I diabetic mouse model. Three experimental groups were used: group 1, non-diabetic control mice; group 2, diabetic mice; and group 3, diabetic mice treated with BV. We found that the diabetic mice exhibited delayed wound closure characterized by a significant decrease in collagen production and prolonged elevation of inflammatory cytokines levels in wounded tissue compared to control non-diabetic mice. Additionally, wounded tissue in diabetic mice revealed aberrantly up-regulated expression of ATF-3 and iNOS followed by a marked elevation in free radical levels. Impaired diabetic wound healing was also characterized by a significant elevation in caspase-3, -8, and -9 activity and a marked reduction in the expression of TGF-β and VEGF, which led to decreased neovascularization and angiogenesis of the injured tissue by impairing EPC mobilization. Interestingly, BV treatment significantly enhanced wound closure in diabetic mice by increasing collagen production and restoring the levels of inflammatory cytokines, free radical, TGF-β, and VEGF. Most importantly, BV-treated diabetic mice exhibited mobilized long-lived EPCs by inhibiting caspase activity in the wounded tissue. Our findings reveal the molecular mechanisms underlying improved diabetic wound healing and closure following BV treatment. J. Cell. Physiol. 231: 2159-2171, 2016. © 2016 Wiley Periodicals, Inc.

MTOR Inhibition With Rapamycin Mitigates Radiation-Induced Pulmonary Fibrosis in a Murine Model

Fibrosis is a late toxicity of radiation in lung. Radiation-induced pulmonary fibrosis (RIPF) is characterized by parenchymal cell depletion, inflammation, fibroblast proliferation, and collagen deposition. mTOR signaling has been implicated in inflammatory cytokine production, fibroblast proliferation, and epithelial stem cell senescence. We sought to determine if mTOR inhibition with rapamycin would mitigate RIPF. C57Bl/6 mice received a diet with rapamycin (14 mg/kg food; 0.056 mg/mouse/day) or control diet beginning one day prior to radiation and continuing until tissue collection or death. Cohorts of mice treated with rapamycin or control diet were exposed to thoracic irradiation in 5 daily fractions of 6 Gy (RT), and followed for survival (n=8 per group) and tissue collection (n=3 per time point). Histologic changes were evaluated by Masson-Trichrome staining at 16 weeks after RT. Inflammatory cytokine expression was evaluated by quantitative real time PCR. Senescence was assessed by staining for beta-galactosidase activity. To define the role of rapamycin in the fibroproliferative response, cell proliferation (MTT assay) and collagen deposition (Hydroxyproline assay) were examined in a mouse fibroblast cell line. Administration of rapamycin increased the median survival of irradiated mice from 116 days to 156 days (log rank p=0.006). At 16 weeks after irradiation, treatment with rapamycin reduced hydroxyproline content compared to vehicle treated irradiated controls (RT+vehicle: 45.9±11.8, RT+rapamycin: 21.4±6.0, or unirradiated+control chow: 25.7±5.0 μg/lung respectively, p=0.001). Mice exposed to RT+vehicle had dense foci of subpleural fibrosis at 16 weeks, a finding largely absent in RT+rapamycin treated mice. Rapamycin treatment attenuated IL-1β and TGF-β induction in lung in response to RT at multiple time points. Cellular senescence was significantly decreased by rapamycin treatment in primary type 2 pneumocytes (4-fold reduction at 5 days after RT, p=0.012) and in lung tissue at 16 weeks after RT (3-fold decrease, p<0.001). Treatment of NIH3T3 fibroblasts with rapamycin (50 ng/ml) resulted in decreased collagen production (1.3-fold decrease at 3 days after RT, p=0.013) and decreased proliferation (1.2-fold decrease, p=0.019). Rapamycin protected against RIPF in murine lungs through a reduction in inflammatory cytokine expression, extra cellular matrix production, and senescence in type2 pneumocytes. Rapamycin has the potential to be an effective therapy option for pulmonary fibrosis following thoracic radiation.

Abstract 1803: A truncated Plasminogen Activator Inhibitor-1 protein protects from pulmonary fibrosis mediated by irradiation in a murine model

Abstract Background: Fibrosis can develop as a late side effect of radiation exposure in a variety of tissues, including lung and skin. Late radiation injury and fibrosis are characterized by parenchymal cell depletion, inflammation, senescence, fibroblast proliferation, and excessive deposition of collagen. Plasminogen activator inhibitor 1 (PAI-1) is a critical mediator of cellular senescence and fibrin stabilization, and its expression is increased in experimental fibrosis models. We sought to determine if inhibition of PAI-1 signaling with a recombinant truncated protein (rPAI-123) would protect from the development of radiation-induced lung injury. Methods: C57Bl/6 mice received intraperitoneal injections of rPAI-123 (5.4 μg/kg/day) or vehicle (PBS) for 18 weeks beginning two days prior to radiation exposure. Cohorts of mice treated with rPAI-123 or vehicle were exposed to thoracic irradiation in 5 daily fractions of 6 Gy (RT), and followed for survival (n = 8 per group) and tissue collection (n = 3 per each time point). Histologic changes in irradiated lungs were evaluated by Masson-Trichrome staining at 19 weeks after RT. Senescence was assessed with staining for beta-galactosidase activity in lung tissue and primary pneumocytes. To define the roles of rPAI-123 in the fibroproliferative response, cell proliferation (MTT assay) and collagen deposition (Hydroxyproline assay) were examined in a mouse fibroblast cell line in vitro. Results: Administration of rPAI-123 increased C57Bl/6 mice survival from 37.5% to 62.5% at 19 weeks after radiation exposure. At 19 weeks after irradiation, hydroxyproline content was markedly decreased in mice received rPAI-123 compared to mice received vehicle (RT+rPAI-123: 56.2±10.79, RT+vehicle: 84.97±2.98, μg/lung respectively, p = 0.001 between RT+vehicle and RT+rPAI-123). C57Bl/6 mice exposed to RT+vehicle had dense foci of subplueral fibrosis at 19 weeks, whereas the lungs of mice exposed to RT+rPAI-123 were largely devoid of fibrotic foci. Cellular senescence in response to radiation was significantly decreased by rPAI-123 treatment in primary type2 pneumocyte culture (2-fold reduction at 5 days after RT, p = 0.036), and in lung tissues (&amp;gt;2-fold reduction at 4, 8, and 16 weeks after RT, p&amp;lt;0.001 at each time point). Treatment of NIH-3T3 fibroblasts with rPAI-123 resulted in decreased collagen production, but had no effect on proliferation.Conclusions: These studies identify that rPAI-123 has a novel protection mechanism against radiation-induced fibrosis in murine lungs due to its ability to reduce senescence in type2 pneumocytes, and the potential to be an effective therapy option for radiation induced fibrosis. Citation Format: Eunjoo Chung, Ayla White, Bradley T. Scroggins, Grace B. McKay-Corkum, Mary Jo Mulligan-Kehoe, Deborah E. Citrin. A truncated Plasminogen Activator Inhibitor-1 protein protects from pulmonary fibrosis mediated by irradiation in a murine model. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1803. doi:10.1158/1538-7445.AM2015-1803

Increased FGF1-FGFRc expression in idiopathic pulmonary fibrosis.

BackgroundRecent clinical studies show that tyrosine kinase inhibitors slow the rate of lung function decline and decrease the number of acute exacerbations in patients with Idiopathic Pulmonary Fibrosis (IPF). However, in the murine bleomycin model of fibrosis, not all tyrosine kinase signaling is detrimental. Exogenous ligands Fibroblast Growth Factor (FGF) 7 and 10 improve murine lung repair and increase survival after injury via tyrosine kinase FGF receptor 2b-signaling. Therefore, the level and location of FGF/FGFR expression as well as the exogenous effect of the most highly expressed FGFR2b ligand, FGF1, was analyzed on human lung fibroblasts.MethodsFGF ligand and receptor expression was evaluated in donor and IPF whole lung homogenates using western blotting and qPCR. Immunohistochemistry for FGF1 and FGFR1/2/3/4 were performed on human lung tissue. Lastly, the effects of FGF1, a potent, multi-FGFR ligand, were studied on primary cultures of IPF and non-IPF donor fibroblasts. Western blots for pro-fibrotic markers, proliferation, FACS for apoptosis, transwell assays and MetaMorph analyses on cell cultures were performed.ResultsWhole lung homogenate analyses revealed decreased FGFR b-isoform expression, and an increase in FGFR c-isoform expression. Of the FGFR2b-ligands, FGF1 was the most significantly increased in IPF patients; downstream targets of FGF-signaling, p-ERK1/2 and p-AKT were also increased. Immunohistochemistry revealed FGF1 co-localization within basal cell sheets, myofibroblast foci, and Surfactant protein-C positive alveolar epithelial type-II cells as well as co-localization with FGFR1, FGFR2, FGFR3, FGFR4 and myofibroblasts expressing the migratory marker Fascin. Both alone and in the presence of heparin, FGF1 led to increased MAPK-signaling in primary lung fibroblasts. While smooth muscle actin was unchanged, heparin + FGF1 decreased collagen production in IPF fibroblasts. In addition, FGF1 + heparin increased apoptosis and cell migration. The FGFR inhibitor (PD173074) attenuated these effects.ConclusionsStrong expression of FGF1/FGFRs in pathogenic regions of IPF suggest that aberrant FGF1-FGFR signaling is increased in IPF patients and may contribute to the pathogenesis of lung fibrosis by supporting fibroblast migration and increased MAPK-signaling.Electronic supplementary materialThe online version of this article (doi:10.1186/s12931-015-0242-2) contains supplementary material, which is available to authorized users.

P47phox contributes to albuminuria and kidney fibrosis in mice

Reactive oxygen species (ROS) play an important pathogenic role in the development of many diseases, including kidney disease. Major ROS generators in the glomerulus of the kidney are the p47phox-containing NAPDH oxidases NOX1 and NOX2. The cytosolic p47phox subunit is a key regulator of the assembly and function of NOX1 and NOX2 and its expression and phosphorylation are up-regulated in the course of renal injury, and have been shown to exacerbate diabetic nephropathy. However, its role in non-diabetic-mediated glomerular injury is unclear. To address this, we subjected p47phox-null mice to either adriamycin-mediated or partial renal ablation-mediated glomerular injury. Deletion of p47phox protected the mice from albuminuria and glomerulosclerosis in both injury models. Integrin α1-null mice develop more severe glomerulosclerosis than wild type mice in response to glomerular injury mainly due to increased production of ROS. Interestingly, the protective effects of p47phox knockout were more profound in p47phox/integrin α1 double knockout mice. In vitro analysis of primary mesangial cells showed that deletion of p47phox led to reduced basal levels of superoxide and collagen IV production. Thus, p47phox-dependent NADPH oxidases are a major glomerular source of ROS, contribute to kidney injury, and are potential targets for antioxidant therapy in fibrotic disease.

Functional and mechanistic investigation of Shikonin in scarring

Scarring is a significant medical burden; financially to the health care system and physically and psychologically for patients. Importantly, there have been numerous case reports describing the occurrence of cancer in burn scars. Currently available therapies are not satisfactory due to their undesirable side-effects, complex delivery routes, requirements for long-term use and/or expense. Radix Arnebiae (Zi Cao), a perennial herb, has been clinically applied to treat burns and manage scars for thousands of years in Asia. Shikonin, an active component extracted from Radix Arnebiae, has been demonstrated to induce apoptosis in cancer cells. Apoptosis is an essential process during scar tissue remodelling. It was therefore hypothesized that Shikonin may induce apoptosis in scar-associated cells. This investigation presents the first detailed in vitro study examining the functional responses of scar-associated cells to Shikonin, and investigates the mechanisms underlying these responses. The data obtained suggests that Shikonin inhibits cell viability and proliferation and reduces detectable collagen in scar-derived fibroblasts. Further investigation revealed that Shikonin induces apoptosis in scar fibroblasts by differentially regulating the expression of caspase 3, Bcl-2, phospho-Erk1/2 and phospho-p38. In addition, Shikonin down-regulates the expression of collagen I, collagen III and alpha-smooth muscle actin genes hence attenuating collagen synthesis in scar-derived fibroblasts. In summary, it is demonstrated that Shikonin induces apoptosis and decreases collagen production in scar-associated fibroblasts and may therefore hold potential as a novel scar remediation therapy.

Hsp70 Knockdown by siRNA Decreased Collagen Production in Keloid Fibroblasts.

PurposeThere are currently no consistently effective treatments for the excessive collagen produced by keloid fibroblasts. Previously, we reported that heat shock protein 70 (Hsp70) is up-regulated in keloid fibroblasts and keloid tissue. We, therefore, investigated whether Hsp70 is related to excessive collagen production in keloid fibroblasts.Materials and MethodsWe inhibited Hsp70 in keloid fibroblasts by RNA interference and examined the resulting collagen expression. Thus, we selected small interfering RNAs (siRNAs) specific for human Hsp70, transfected them into keloid fibroblasts, and evaluated the resulting phenotypes and protein production using real-time polymerase chain reaction (PCR), Western blot, and a collagen assay.ResultsThe siRNAs dramatically suppressed Hsp70 mRNA expression, resulting in a decrease in collagen production in the keloid fibroblasts compared with controls. The siRNAs did not influence the viability of the keloid fibroblasts.ConclusionHsp70 overexpression likely plays an important role in the excessive collagen production by keloid fibroblasts. RNA interference has therapeutic potential for the treatment of keloids.

The four-herb Chinese medicine ANBP enhances wound healing and inhibits scar formation via bidirectional regulation of transformation growth factor pathway.

The four-herb Chinese medicine ANBP is a pulverized mixture of four herbs including Agrimonia Eupatoria (A), Nelumbo Nucifera Gaertn (N), Boswellia Carteri (B) and Pollen Typhae Angustifoliae (P). The combination of the four herbs was first described in Chinese canonical medicine about 2000 years ago for treatment of various trauma disorders, such as hemostasis, antiinflammatory, analgesia, and wound healing, etc. However, the precise mechanisms of ANBP are still unclear. In our study, using rabbit ear hypertrophic scar models of full-thickness skin defect, we showed that local ANBP treatment not only significantly enhanced wound healing by relieving inflammation, increasing formation of granulation tissue and accelerating re-epithelialization, but also reduced scar formation by decreasing collagen production, protuberant height and volume of scars, and increasing collagen maturity. We demonstrated that these effects of ANBP are associated with transforming growth factor (TGF)-β1-mediated signalling pathways through Smad-dependent pathways. ANBP treatment significantly increased expression of TGF-β1 and Smad2/3 mRNA at the early stage of wound healing, and led to markedly decrease expression of TGF-β1 and Smad2/3 compared with the control group after 14 days post-wounding. Taken together, our results defined a bidirectional regulation role of ANBP for TGF-β1/Smad pathway in promoting wound healing and alleviating scar formation, which may be an effective therapy for human wounds at the earliest stage.

Aspirin-triggered 15-epi-lipoxin A4 signals through FPR2/ALX in vascular smooth muscle cells and protects against intimal hyperplasia after carotid ligation

Aspirin-triggered 15-epi-lipoxin A4 signals through FPR2/ALX in vascular smooth muscle cells and protects against intimal hyperplasia after carotid ligation

The role of the FPR2/ALX receptor in atherosclerosis development and plaque stability.

AimsThe formyl peptide receptor (FPR) subtype FPR2/ALX transduces pro-inflammatory responses and participates in the resolution of inflammation depending on activation. The aim of the present study was to unravel the role of FPR2/ALX signalling in atherosclerosis.Methods and resultsExpression of FPR2/ALX was analysed in 127 human carotid atherosclerotic lesions and revealed that this receptor was expressed on macrophages, smooth muscle cells (SMCs), and endothelial cells. Furthermore, FPR2/ALX mRNA levels were significantly up-regulated in atherosclerotic lesions compared with healthy vessels. In multiple regression, age, creatinine, and clinical signs of increased cerebral ischaemia were independent predictors of FPR2/ALX expression. To provide mechanistic insights into these observations, we generated Ldlr−/−xFpr2−/− mice, which exhibited delayed atherosclerosis development and less macrophage infiltration compared with Ldlr−/−xFpr2+/+ mice. These findings were reproduced by transplantation of Fpr2−/− bone marrow into Ldlr−/− mice and further extended by in vitro experiments, demonstrating a lower inflammatory state in Fpr2−/− macrophages. FPR2/ALX expression correlated with chemo- and cytokines in human atherosclerotic lesions and leucocytes. Finally, atherosclerotic lesions in Ldlr−/−xFpr2−/− mice exhibited decreased collagen content, and Fpr2−/− SMCs exhibited a profile of increased collagenase and decreased collagen production pathways.ConclusionFPR2/ALX is proatherogenic due to effects on bone marrow-derived cells, but promoted a more stable plaque phenotype through effects on SMCs. Taken together, these results suggest a dual role of FPR2/ALX signalling in atherosclerosis by way of promoting disease progression and but increasing plaque stability.

Engineering cellular response using nanopatterned bulk metallic glass.

Nanopatterning of biomaterials is rapidly emerging as a tool to engineer cell function. Bulk metallic glasses (BMGs), a class of biocompatible materials, are uniquely suited to study nanopattern–cell interactions as they allow for versatile fabrication of nanopatterns through thermoplastic forming. Work presented here employs nanopatterned BMG substrates to explore detection of nanopattern feature sizes by various cell types, including cells that are associated with foreign body response, pathology, and tissue repair. Fibroblasts decreased in cell area as the nanopattern feature size increased, and fibroblasts could detect nanopatterns as small as 55 nm in size. Macrophages failed to detect nanopatterns of 150 nm or smaller in size, but responded to a feature size of 200 nm, resulting in larger and more elongated cell morphology. Endothelial cells responded to nanopatterns of 100 nm or larger in size by a significant decrease in cell size and elongation. On the basis of these observations, nondimensional analysis was employed to correlate cellular morphology and substrate nanotopography. Analysis of the molecular pathways that induce cytoskeletal remodeling, in conjunction with quantifying cell traction forces with nanoscale precision using a unique FIB-SEM technique, enabled the characterization of underlying biomechanical cues. Nanopatterns altered serum protein adsorption and effective substrate stiffness, leading to changes in focal adhesion density and compromised activation of Rho-A GTPase in fibroblasts. As a consequence, cells displayed restricted cell spreading and decreased collagen production. These observations suggest that topography on the nanoscale can be designed to engineer cellular responses to biomaterials.