Extracellular Matrix Turnover Research Articles

Retinal Protection from LED-Backlit Screen Lights by Short Wavelength Absorption Filters.

(1) Background: Ocular exposure to intense light or long-time exposure to low-intensity short-wavelength lights may cause eye injury. Excessive levels of blue light induce photochemical damage to the retinal pigment and degeneration of photoreceptors of the outer segments. Currently, people spend a lot of time watching LED screens that emit high proportions of blue light. This study aims to assess the effects of light emitted by LED tablet screens on pigmented rat retinas with and without optical filters. (2) Methods: Commercially available tablets were used for exposure experiments on three groups of rats. One was exposed to tablet screens, the other was exposed to the tablet screens with a selective filter and the other was a control group. Structure, gene expression (including life/death, extracellular matrix degradation, growth factors, and oxidative stress related genes), and immunohistochemistry in the retina were compared among groups. (3) Results: There was a reduction of the thickness of the external nuclear layer and changes in the genes involved in cell survival and death, extracellular matrix turnover, growth factors, inflammation, and oxidative stress, leading decrease in cell density and retinal damage in the first group. Modulation of gene changes was observed when the LED light of screens was modified with an optical filter. (4) Conclusions: The use of short-wavelength selective filters on the screens contribute to reduce LED light-induced damage in the rat retina.

Abstract 12186: The Role of Extracellular Matrix Turnover in Early Diastolic Recoil Efficiency

Introduction: Diastolic recoil is an important component of cardiac relaxation and depends on the efficient recovery of energy stored in cardiac tissue during systolic deformation. Abnormalities in the cardiac extracellular matrix (ECM) have been implicated in cardiovascular remodeling and diastolic dysfunction. Matrix metalloproteinases (MMPs) and their endogenous inhibitors, tissue inhibitors of MMPs (TIMPs) regulate protein deposition and degradation in the ECM. We compared MMP and TIMP profiles in healthy seniors to study the role of ECM turnover in diastolic recoil efficiency. Hypothesis: Increased levels of MMPs and TIMPs involved in ECM protein turnover will be associated with improved diastolic recoil efficiency. Methods: Healthy but sedentary seniors (13 men, 9 women; age 68 ± 8 yrs) underwent echocardiogram and plasma biomarker assay for human MMP 1, 2, 3, 7, 9 and TIMP 1, 2, 3, 4. Diastolic recoil efficiency was modeled as an elastic spring and measured as the ratio of systolic longitudinal excursion (Sexc) and early diastolic excursion (EDexc) obtained from tissue doppler velocity-time integrals. Results: Increasing EDexc/Sexc ratios were directly associated with TIMP-1 levels (R=0.45, p=0.035) and TIMP-4 levels (R=0.50, p=0.019). There was a trend towards an association with MMP-2 (R=0.76, p=0.076). There were no significant correlations between the EDexc/Sex ratio and MMPs 1, 3, 7 or 9, TIMPs 2 or 3, MMP2/TIMP1, MMP2/TIMP4, MMP9/TIMP1, or MMP9/TIMP4 ratios. Conclusions: Abnormalities in ECM deposition and degradation via MMPs and TIMPs may impact cardiac relaxation by altering the efficiency of energy recovery in the transition from systole to diastole. TIMP-1 and -4 may preserve diastolic efficiency by attenuating fibrillar collagen fragmentation and pathologic remodeling of the ECM. MMP-2 trended towards a positive association with diastolic recoil efficiency and likely mediates a beneficial effect outside of its proteolytic action.

Takotsubo syndrome: a way to reach a straightforward diagnosis

Abstract Background/Introduction Acute stress-induced cardiomyopathy, also known as Takotsubo Syndrome (TTS), was originally classified as a benign disease. Nowadays, this assumption has changed, especially in its long-term outcome, due to TTS clinical presentation, that often mirrors the acute myocardial infarction (MI) phenotype. Current knowledge already delineate clinical features distinctive of TTS and MI patients, however, diagnosis requires multiple, expansive, and invasive medical examinations. Moreover, concerning the biological panorama, very slight is known and the lack of a tailored therapy is resented. Therefore, a biological profile for this clinical category could provide easier and less invasive diagnostic tools, leading edge towards novel therapeutic pathways. Purpose The aim of the study is to perform a biological profile of the TTS group compared to the ST Segment Elevation Myocardial Infarction (STEMI) in order to explore the molecular peculiarities attendant the pathophysiologic mechanisms. Methods We performed a gene expression array on two groups of pooled cDNA from peripheral blood mononuclear cells, from TTS (n=11) and STEMI (n=19) patients. We conducted gene expression validations for each enrolled patient through qPCR. Results Our preliminary data displayed several differences in gene expression levels of a grand number of cell adhesion signaling molecule between the two groups. As shown in figure 1, three gene were more expressed in TTS group: Nitric Oxide Synthase 3, also known as endothelial NOS (NOS3; p=0.002), Superoxide dismutase 1 (SOD1; p=0.03) and transferrin receptor (TFRC; p=0.005). Meanwhile, five gene displayed a higher expression in STEMI patients compared to TTS: phospholipase A2 Group 7 (PLA2G7; p=0.04), Galectin 8 (LGALS8; p=0.02), Intercellular Adhesion Molecule 1 (ICAM1; p=0.002), Hyaluronidase 2 (HYAL2; p=0.01) and Hyaluronan Receptor (CD44; p=0.0002). Conclusions The earliest results of this study led us to focus on fewer genes related to endothelial and oxidative stress pathways. TTS is habitually triggered by intense emotional or physical stress. Indeed, our results showed how TTS patients present higher expression of NOS3, SOD1 and TFRC, all components involved in the oxidative stress pathways. In STEMI patients, top expressed genes, such as HYAL2, CD44 and ICAM1, are all associated with extracellular matrix turnover, likely due to the presence of a stenotic plaque and the consequent endothelial derangement. The uncovering of diagnostic biomarkers in TTS might improve the early, non-invasive, stratification of this group of patients, thus facilitating novel and personalized therapeutics design. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The present study was supported by the Italian National Project Grant PRIN 2017.

Biomarker-Based Guideline-Directed Medical Therapy of Heart Failure: The Gap Between Guidelines and Clinical Practice

Current clinical recommendations provided by the 2016 European Society of Cardiology (ESC) and 2017 American College of Cardiology (ACC)/American Heart Association (AHA)/Heart Failure Society of America (HFSA) are substantially distinguished in the use of circulating biomarkers in the management of heart failure (HF). To date, natriuretic peptides continue being the universal biomarkers used in diagnosis, risk stratification, and prediction of cardiovascular death, all-cause mortality, and HF-related outcomes for patients with both phenotypes of HF. However, biomarkers of fibrosis and inflammation, including soluble suppressor of tumourgenicity 2 and galectin-3, were able to increase predictive ability of natriuretic peptides in HF patients regardless of cardiovascular risk-factor presentation and HF phenotypes. Therefore, there are many various biomarkers describing several pathophysiological processes such as fibrosis, inflammation, oxidative stress, neurohumoral activation, extracellular matrix turnover, and vascular reparation, that play a pivotal role in the natural evolution of HF. This review discusses whether multiple biomarker models are more effective than a single biomarker in improving risk stratification strategies in patients with HF. It emphasises how in routine clinical practice, the multiple biomarker approach to elicit response to therapy of HF and predict clinical outcomes is rare, probably because of the relatively high cost, low affordability, lack of clear recommendations for clinical implementation, and significant disagreements in the interpretation of the data obtained.

Biomarker-Based Guideline-Directed Medical Therapy of Heart Failure: The Gap Between Guidelines and Clinical Practice

Current clinical recommendations provided by the 2016 European Society of Cardiology (ESC) and 2017 American College of Cardiology (ACC)/American Heart Association (AHA)/Heart Failure Society of America (HFSA) are substantially distinguished in the use of circulating biomarkers in the management of heart failure (HF). To date, natriuretic peptides continue being the universal biomarkers used in diagnosis, risk stratification, and prediction of cardiovascular death, all-cause mortality, and HF-related outcomes for patients with both phenotypes of HF. However, biomarkers of fibrosis and inflammation, including soluble suppressor of tumourgenicity 2 and galectin-3, were able to increase predictive ability of natriuretic peptides in HF patients regardless of cardiovascular risk-factor presentation and HF phenotypes. Therefore, there are many various biomarkers describing several pathophysiological processes such as fibrosis, inflammation, oxidative stress, neurohumoral activation, extracellular matrix turnover, and vascular reparation, that play a pivotal role in the natural evolution of HF. This review discusses whether multiple biomarker models are more effective than a single biomarker in improving risk stratification strategies in patients with HF. It emphasises how in routine clinical practice, the multiple biomarker approach to elicit response to therapy of HF and predict clinical outcomes is rare, probably because of the relatively high cost, low affordability, lack of clear recommendations for clinical implementation, and significant disagreements in the interpretation of the data obtained.

GYY4137 Regulates Extracellular Matrix Turnover in the Diabetic Kidney by Modulating Retinoid X Receptor Signaling.

Diabetic kidney is associated with an accumulation of extracellular matrix (ECM) leading to renal fibrosis. Dysregulation of retinoic acid metabolism involving retinoic acid receptors (RARs) and retinoid X receptors (RXRs) has been shown to play a crucial role in diabetic nephropathy (DN). Furthermore, RARs and peroxisome proliferator-activated receptor γ (PPARγ) are known to control the RXR-mediated transcriptional regulation of several target genes involved in DN. Recently, RAR and RXR have been shown to upregulate plasminogen activator inhibitor-1 (PAI-1), a major player involved in ECM accumulation and renal fibrosis during DN. Interestingly, hydrogen sulfide (H2S) has been shown to ameliorate adverse renal remodeling in DN. We investigated the role of RXR signaling in the ECM turnover in diabetic kidney, and whether H2S can mitigate ECM accumulation by modulating PPAR/RAR-mediated RXR signaling. We used wild-type (C57BL/6J), diabetic (C57BL/6-Ins2Akita/J) mice and mouse mesangial cells (MCs) as experimental models. GYY4137 was used as a H2S donor. Results showed that in diabetic kidney, the expression of PPARγ was decreased, whereas upregulations of RXRα, RXRβ, and RARγ1 expression were observed. The changes were associated with elevated PAI-1, MMP-9 and MMP-13. In addition, the expressions of collagen IV, fibronectin and laminin were increased, whereas elastin expression was decreased in the diabetic kidney. Excessive collagen deposition was observed predominantly in the peri-glomerular and glomerular regions of the diabetic kidney. Immunohistochemical localization revealed elevated expression of fibronectin and laminin in the glomeruli of the diabetic kidney. GYY4137 reversed the pathological changes. Similar results were observed in in vitro experiments. In conclusion, our data suggest that RXR signaling plays a significant role in ECM turnover, and GYY4137 modulates PPAR/RAR-mediated RXR signaling to ameliorate PAI-1-dependent adverse ECM turnover in DN.

FKBP51 promotes invasion and migration by increasing the autophagic degradation of TIMP3 in clear cell renal cell carcinoma

The occurrence of metastasis is a serious risk for renal cell carcinoma (RCC) patients. In order to develop novel therapeutic approaches to control the progression of metastatic RCC, it is of urgent need to understand the molecular mechanisms underlying RCC metastasis and identify prognostic markers of metastatic risk. Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) have been known to be closely associated with extracellular matrix (ECM) turnover, which plays a highly active role in tumor metastasis. Recent studies have shown that immunophilin FK-506-binding protein 51 (FKBP51) may be important for the regulation of ECM function, and exert effects on the invasion and migration of tumor cells. However, the mechanisms underlying these activities remain unclear. The present study detected the role of FKBP51 in clear cell renal cell carcinoma (ccRCC), the most common subtype of RCC, and found that FKBP51 significantly promotes ccRCC invasion and migration by binding with the TIMP3, connecting TIMP3 with Beclin1 complex and increasing autophagic degradation of TIMP3. Given the important roles that TIMPs/MMPs play in ECM regulation and remodeling, our findings will provide new perspective for future investigation of the regulation of metastasis of kidney cancer and other types of cancer.

Matrix metalloproteinase-1 as a non-invasive biomarker to assess liver fibrosis in children with chronic liver disease

BackgroundAbnormal extracellular matrix (ECM) turnover is linked to liver fibrosis as it reflects an imbalance between repair and progressive substitution of the liver parenchyma by scar tissue. Matrix metalloproteinases (MMPs) are the primary enzymes involved in ECM breakdown. So, this study aims to measure the value of serum matrix metalloproteinase-1 (MMP-1) in children with chronic liver diseases (CLD) in comparison with liver biopsy and serum biomarkers. A hundred twenty children with chronic liver diseases and sixty healthy children as a control group were included in this study. Both groups were evaluated via medical history, clinical, radiological, laboratory investigations, and serum MMP-1 level was measured by ELISA. Liver biopsy was performed for studied patients only.ResultsThe mean MMP-1 was 15.2 ± 5.1 ng/ml in children with CLD, and 64.7 ± 27.4 ng/ml in the control group. MMP-1 was statistically lower in the children with CLD than controls (p < 0.001). The mean ± SD of aspartate aminotransferase to platelet ratio index (APRI) and fibrosis-4 (FIB-4) scores in all studied cases showed a significant trend of increase with progressive fibrosis stage evident with histological METAVIR scoring system, while serum MMP-1 concentration was decreased significantly with increasing the degree of fibrosis in CLD group (P 0.001). Serum MMP-1 was indirectly correlated with serum biomarkers and the degree of fibrosis in patients.ConclusionsMMP-1 is a useful non-invasive marker for detection of the stage of liver fibrosis in children with chronic liver diseases.

Cardiovascular Drugs and Osteoarthritis: Effects of Targeting Ion Channels

Osteoarthritis (OA) and cardiovascular diseases (CVD) share many similar features, including similar risk factors and molecular mechanisms. A great number of cardiovascular drugs act via different ion channels and change ion balance, thus modulating cell metabolism, osmotic responses, turnover of cartilage extracellular matrix and inflammation. These drugs are consumed by patients with CVD for many years; however, information about their effects on the joint tissues has not been fully clarified. Nevertheless, it is becoming increasingly likely that different cardiovascular drugs may have an impact on articular tissues in OA. Here, we discuss the potential effects of direct and indirect ion channel modulating drugs, including inhibitors of voltage gated calcium and sodium channels, hyperpolarization-activated cyclic nucleotide-gated channels, β-adrenoreceptor inhibitors and angiotensin-aldosterone system affecting drugs. The aim of this review was to summarize the information about activities of cardiovascular drugs on cartilage and subchondral bone and to discuss their possible consequences on the progression of OA, focusing on the modulation of ion channels in chondrocytes and other joint cells, pain control and regulation of inflammation. The implication of cardiovascular drug consumption in aetiopathogenesis of OA should be considered when prescribing ion channel modulators, particularly in long-term therapy protocols.

Transcriptomic Analysis of the Differential Nephrotoxicity of Diverse Brominated Flame Retardants in Rat and Human Renal Cells.

Brominated flame retardants (BFRs) are environmentally persistent, are detected in humans, and some have been banned due to their potential toxicity. BFRs are developmental neurotoxicants and endocrine disruptors; however, few studies have explored their potential nephrotoxicity. We addressed this gap in the literature by determining the toxicity of three different BFRs (tetrabromobisphenol A (TBBPA), hexabromocyclododecane (HBCD), and tetrabromodiphenyl ether (BDE-47)) in rat (NRK 52E) and human (HK-2 and RPTEC) tubular epithelial cells. All compounds induced time- and concentration-dependent toxicity based on decreases in MTT staining and changes in cell and nuclear morphology. The toxicity of BFRs was chemical- and cell-dependent, and human cells were more susceptible to all three BFRs based on IC50s after 48 h exposure. BFRs also had chemical- and cell-dependent effects on apoptosis as measured by increases in annexin V and PI staining. The molecular mechanisms mediating this toxicity were investigated using RNA sequencing. Principal components analysis supported the hypothesis that BFRs induce different transcriptional changes in rat and human cells. Furthermore, BFRs only shared nine differentially expressed genes in rat cells and five in human cells. Gene set enrichment analysis demonstrated chemical- and cell-dependent effects; however, some commonalities were also observed. Namely, gene sets associated with extracellular matrix turnover, the coagulation cascade, and the SNS-related adrenal cortex response were enriched across all cell lines and BFR treatments. Taken together, these data support the hypothesis that BFRs induce differential toxicity in rat and human renal cell lines that is mediated by differential changes in gene expression.

Fibronectin: Molecular Structure, Fibrillar Structure and Mechanochemical Signaling.

The extracellular matrix (ECM) plays a key role as both structural scaffold and regulator of cell signal transduction in tissues. In times of ECM assembly and turnover, cells upregulate assembly of the ECM protein, fibronectin (FN). FN is assembled by cells into viscoelastic fibrils that can bind upward of 40 distinct growth factors and cytokines. These fibrils play a key role in assembling a provisional ECM during embryonic development and wound healing. Fibril assembly is also often upregulated during disease states, including cancer and fibrotic diseases. FN fibrils have unique mechanical properties, which allow them to alter mechanotransduction signals sensed and relayed by cells. Binding of soluble growth factors to FN fibrils alters signal transduction from these proteins, while binding of other ECM proteins, including collagens, elastins, and proteoglycans, to FN fibrils facilitates the maturation and tissue specificity of the ECM. In this review, we will discuss the assembly of FN fibrils from individual FN molecules; the composition, structure, and mechanics of FN fibrils; the interaction of FN fibrils with other ECM proteins and growth factors; the role of FN in transmitting mechanobiology signaling events; and approaches for studying the mechanics of FN fibrils.

Abnormal B-cell development in TIMP-deficient bone marrow

AbstractBone marrow (BM) is the primary site of hematopoiesis and is responsible for a lifelong supply of all blood cell lineages. The process of hematopoiesis follows key intrinsic programs that also integrate instructive signals from the BM niche. First identified as an erythropoietin-potentiating factor, the tissue inhibitor of metalloproteinase (TIMP) protein family has expanded to 4 members and has widely come to be viewed as a classical regulator of tissue homeostasis. By virtue of metalloprotease inhibition, TIMPs not only regulate extracellular matrix turnover but also control growth factor bioavailability. The 4 mammalian TIMPs possess overlapping enzyme-inhibition profiles and have never been studied for their cumulative role in hematopoiesis. Here, we show that TIMPs are critical for postnatal B lymphopoiesis in the BM. TIMP-deficient mice have defective B-cell development arising at the pro-B-cell stage. Expression analysis of TIMPless hematopoietic cell subsets pointed to an altered B-cell program in the Lineage−Sca-1+c-Kit+ (LSK) cell fraction. Serial and competitive BM transplants identified a defect in TIMP-deficient hematopoietic stem and progenitor cells for B lymphopoiesis. In parallel, reverse BM transplants uncovered the extrinsic role of stromal TIMPs in pro- and pre-B-cell development. TIMP deficiency disrupted CXCL12 localization to LepR+ cells, and increased soluble CXCL12 within the BM niche. It also compromised the number and morphology of LepR+ cells. These data provide new evidence that TIMPs control the cellular and biochemical makeup of the BM niche and influence the LSK transcriptional program required for optimal B lymphopoiesis.

Molecular Insights in Atrial Fibrillation Pathogenesis and Therapeutics: A Narrative Review.

The prevalence of atrial fibrillation (AF) is bound to increase globally in the following years, affecting the quality of life of millions of people, increasing mortality and morbidity, and beleaguering health care systems. Increasingly effective therapeutic options against AF are the constantly evolving electroanatomic substrate mapping systems of the left atrium (LA) and ablation catheter technologies. Yet, a prerequisite for better long-term success rates is the understanding of AF pathogenesis and maintenance. LA electrical and anatomical remodeling remains in the epicenter of current research for novel diagnostic and treatment modalities. On a molecular level, electrical remodeling lies on impaired calcium handling, enhanced inwardly rectifying potassium currents, and gap junction perturbations. In addition, a wide array of profibrotic stimuli activates fibroblast to an increased extracellular matrix turnover via various intermediaries. Concomitant dysregulation of the autonomic nervous system and the humoral function of increased epicardial adipose tissue (EAT) are established mediators in the pathophysiology of AF. Local atrial lymphomononuclear cells infiltrate and increased inflammasome activity accelerate and perpetuate arrhythmia substrate. Finally, impaired intracellular protein metabolism, excessive oxidative stress, and mitochondrial dysfunction deplete atrial cardiomyocyte ATP and promote arrhythmogenesis. These overlapping cellular and molecular alterations hinder us from distinguishing the cause from the effect in AF pathogenesis. Yet, a plethora of therapeutic modalities target these molecular perturbations and hold promise in combating the AF burden. Namely, atrial selective ion channel inhibitors, AF gene therapy, anti-fibrotic agents, AF drug repurposing, immunomodulators, and indirect cardiac neuromodulation are discussed here.

Biomarkers of extracellular matrix formation are associated with acute-on-chronic liver failure

Background & AimsAcute-on-chronic liver failure (ACLF) is characterised by organ failure(s), high short-term mortality, and, pathophysiologically, deranged inflammatory responses. The extracellular matrix (ECM) is critically involved in regulating the inflammatory response. This study aimed to determine alterations in biomarkers of ECM turnover in ACLF and their association with inflammation, organ failures, and mortality.MethodsWe studied 283 patients with cirrhosis admitted for acute decompensation (AD) with or without ACLF, 64 patients with stable cirrhosis, and 30 healthy controls. A validation cohort (25 ACLF, 9 healthy controls) was included. Plasma PRO-C3, PRO-C4, PRO-C5, PRO-C6, and PRO-C8 (i.e. collagen type III–VI and VIII formation) and C4M and C6M (i.e. collagen type IV and VI degradation) were measured. Immunohistochemistry of PRO-C6 was performed on liver biopsies (AD [n = 7], ACLF [n = 5]). A competing-risk regression analysis was performed to explore the prognostic value of biomarkers of ECM turnover with 28- and 90-day mortality.ResultsPRO-C3 and PRO-C6 were increased in ACLF compared to AD (p = 0.089 and p <0.001, respectively), whereas collagen degradation markers C4M and C6M were similar. Both PRO-C3 and PRO-C6 were strongly associated with liver function and inflammatory markers. Only PRO-C6 was associated with extrahepatic organ failures and 28- and 90-day mortality (hazard ratio [HR; on log-scale] 6.168, 95% CI 2.366–16.080, p <0.001, and 3.495, 95% CI 1.509–8.093, p = 0.003, respectively). These findings were consistent in the validation cohort. High PRO-C6 expression was observed in liver biopsies of patients with ACLF.ConclusionsThis study shows, for the first time, evidence of severe net interstitial collagen deposition in ACLF and makes the novel observation of the association between PRO-C6 and (extrahepatic) organ failures and mortality. Further studies are needed to define the pathogenic significance of these observations.Lay summaryThis study describes a disrupted turnover of collagen type III and VI in Acute-on-chronic liver failure (ACLF). Plasma biomarkers of these collagens (PRO-C3 and PRO-C6) are associated with the severity of liver dysfunction and inflammation. PRO-C6, also known as the hormone endotrophin, has also been found to be associated with multi-organ failure and prognosis in acute decompensation and ACLF.

Activation of Pancreatic Stellate Cells Is Beneficial for Exocrine but Not Endocrine Cell Differentiation in the Developing Human Pancreas.

Pancreatic stellate cells (PaSCs) are non-endocrine, mesenchymal-like cells that reside within the peri-pancreatic tissue of the rodent and human pancreas. PaSCs regulate extracellular matrix (ECM) turnover in maintaining the integrity of pancreatic tissue architecture. Although there is evidence indicating that PaSCs are involved in islet cell survival and function, its role in islet cell differentiation during human pancreatic development remains unclear. The present study examines the expression pattern and functional role of PaSCs in islet cell differentiation of the developing human pancreas from late 1st to 2nd trimester of pregnancy. The presence of PaSCs in human pancreata (8–22 weeks of fetal age) was characterized by ultrastructural, immunohistological, quantitative RT-PCR and western blotting approaches. Using human fetal PaSCs derived from pancreata at 14–16 weeks, freshly isolated human fetal islet-epithelial cell clusters (hIECCs) were co-cultured with active or inactive PaSCs in vitro. Ultrastructural and immunofluorescence analysis demonstrated a population of PaSCs near ducts and newly formed islets that appeared to make complex cell-cell dendritic-like contacts. A small subset of PaSCs co-localized with pancreatic progenitor-associated transcription factors (PDX1, SOX9, and NKX6-1). PaSCs were highly proliferative, with significantly higher mRNA and protein levels of PaSC markers (desmin, αSMA) during the 1st trimester of pregnancy compared to the 2nd trimester. Isolated human fetal PaSCs were identified by expression of stellate cell markers and ECM. Suppression of PaSC activation, using all-trans retinoic acid (ATRA), resulted in reduced PaSC proliferation and ECM proteins. Co-culture of hIECCs, directly on PaSCs or indirectly using Millicell® Inserts or using PaSC-conditioned medium, resulted in a reduction the number of insulin+ cells but a significant increase in the number of amylase+ cells. Suppression of PaSC activation or Notch activity during the co-culture resulted in an increase in beta-cell differentiation. This study determined that PaSCs, abundant during the 1st trimester of pancreatic development but decreased in the 2nd trimester, are located near ductal and islet structures. Direct and indirect co-cultures of hIECCs with PaSCs suggest that activation of PaSCs has opposing effects on beta-cell and exocrine cell differentiation during human fetal pancreas development, and that these effects may be dependent on Notch signaling.

DNA Methylation of Fibroblast Phenotypes and Contributions to Lung Fibrosis

Fibroblasts are an integral part of connective tissue and play a crucial role in developing and modulating the structural framework of tissues by acting as the primary source of extracellular matrix (ECM). A precise definition of the fibroblast remains elusive. Lung fibroblasts orchestrate the assembly and turnover of ECM to facilitate gas exchange alongside performing immune functions including the secretion of bioactive molecules and antigen presentation. DNA methylation is the covalent attachment of a methyl group to primarily cytosines within DNA. DNA methylation contributes to diverse cellular phenotypes from the same underlying genetic sequence, with DNA methylation profiles providing a memory of cellular origin. The lung fibroblast population is increasingly viewed as heterogeneous with between 6 and 11 mesenchymal populations identified across health and lung disease to date. DNA methylation has been associated with different lung fibroblast populations in health and with alterations in lung disease, but to varying extents. In this review, we will discuss lung fibroblast heterogeneity and the evidence for a contribution from DNA methylation to defining cell populations and alterations in disease.

Identification of Broad-Spectrum MMP Inhibitors by Virtual Screening.

Matrix metalloproteinases (MMPs) are the family of proteases that are mainly responsible for degrading extracellular matrix (ECM) components. In the skin, the overexpression of MMPs as a result of ultraviolet radiation triggers an imbalance in the ECM turnover in a process called photoaging, which ultimately results in skin wrinkling and premature skin ageing. Therefore, the inhibition of different enzymes of the MMP family at a topical level could have positive implications for photoaging. Considering that the MMP catalytic region is mostly conserved across different enzymes of the MMP family, in this study we aimed to design a virtual screening (VS) workflow to identify broad-spectrum MMP inhibitors that can be used to delay the development of photoaging. Our in silico approach was validated in vitro with 20 VS hits from the Specs library that were not only structurally different from one another but also from known MMP inhibitors. In this bioactivity assay, 18 of the 20 compounds inhibit at least one of the assayed MMPs at 100 μM (with 5 of them showing around 50% inhibition in all the tested MMPs at this concentration). Finally, this VS was used to identify natural products that have the potential to act as broad-spectrum MMP inhibitors and be used as a treatment for photoaging.

Matrix Metalloproteinases (MMPs) and Inhibitors of MMPs in the Avian Reproductive System: An Overview.

Many matrix metalloproteinases (MMPs) are produced in the mammalian reproductive system and participate in the regulation of its functions. In birds, the limited information available thus far indicates that MMPs are significant regulators of avian ovarian and oviductal functions, too. Some MMPs and inhibitors of MMPs are present in the hen reproductive tissues and their abundances and/or activities change according to the physiological state. The intraovarian role of MMPs likely includes the remodeling of the extracellular matrix (ECM) during folliculogenesis, follicle atresia, and postovulatory regression. In the oviduct, MMPs are also involved in ECM turnover during oviduct development and regression. This study provides a review of the current knowledge on the presence, activity, and regulation of MMPs in the female reproductive system of birds.

Dual integrin αvβ3 and αvβ5 blockade attenuates cardiac dysfunction by reducing fibrosis in a rat model of doxorubicin-induced cardiomyopathy

Objective The present study aimed to evaluate the protective role of cilengitide (CGT), an integrin αvβ3 and αvβ5 inhibitor, on doxorubicin (DOX)-induced myocardial fibrosis and cardiac dysfunction in a rat model. Methods. Forty male rats were randomly divided into four groups: DOX (n = 12), intraperitoneal (i.p.) injection of DOX 0.8 ∼ 1.0 mg/kg three times a week for up to 6 weeks, then saline i.p. three times a week for another 3 weeks; CGT (n = 8), CGT 10 mg/kg, i.p. three times a week for 9 weeks; DOX + CGT (n = 12), DOX and CGT co-administration as above for 6 weeks, then CGT alone for another 3 weeks; Control (n = 8), saline i.p. three times a week for 9 weeks. Echocardiography, serum procollagen I C-terminal propeptide (PICP) procollagen III N-terminal propeptide (PIIINP) and C telopeptide type I (CTX-I) were evaluated at baseline and 3, 6 and 9 weeks after initial DOX administration for all surviving rats. The heart tissues were then harvested for myocardial hydroxyproline (HYP) evaluation, qRT-PCR, and western blotting. Results. CGT attenuated DOX-induced eccentric remodeling by improving relative wall thickness at the 9th week. CGT also improved systolic function at the 9th week and diastolic function at the 6th and 9th week. CGT reduced myocardial HYP and serum PICP, PIIINP, CTX-I, and the PICP/PIIINP ratio. RT-PCR and western blot showed that CGT blocked the TGF-β1/SMAD3 pathway and mitigating extracellular matrix turnover. Conclusions. CGT exerted a cardioprotective effect against doxorubicin-induced fibrosis and improved cardiac function.

Primary angle closure glaucoma is characterized by altered extracellular matrix homeostasis in the iris.

To characterize the proteome of the iris in primary angle closure glaucoma (PACG). In this cross-sectional study, iris samples were obtained from surgical iridectomy of 48 adults with PACG and five normal controls. Peptides from iris were analysed using liquid chromatography-tandem mass spectrometry on an Orbitrap Q Exactive Plus mass spectrometer. Verification of proteins of interest was conducted using selected reaction monitoring on a triple quadrupole mass spectrometer. The main outcome was proteins with a log2 two-fold difference in expression in iris between PACG and controls. There were 3,446 non-redundant proteins identified in human iris, of which 416 proteins were upregulated and 251 proteins were downregulated in PACG compared with controls. Thirty-two upregulated proteins were either components of the extracellular matrix (ECM) (fibrillar collagens, EMILIN-2, fibrinogen, fibronectin, matrilin-2), matricellular proteins (thrombospondin-1), proteins involved in cell-matrix interactions (integrins, laminin, histidine-rich glycoprotein, paxillin), or protease inhibitors known to modulate ECM turnover (α-2 macroglobulin, tissue factor pathway inhibitor 2, papilin). Two giant proteins, titin and obscurin, were up- and down-regulated, respectively, in the iris in PACG compared with controls. This proteomic study shows that ECM composition and homeostasis are altered in the iris in PACG.