Extracellular Matrix Upregulation Research Articles

Thrombospondin-1 promotes fibro-adipogenic stromal expansion and contractile dysfunction of the diaphragm in obesity.

Pulmonary disorders affect 40%-80% of individuals with obesity. Respiratory muscle dysfunction is linked to these conditions; however, its pathophysiology remains largely undefined. Mice subjected to diet-induced obesity (DIO) develop diaphragm muscle weakness. Increased intradiaphragmatic adiposity and extracellular matrix (ECM) content correlate with reductions in contractile force. Thrombospondin-1 (THBS1) is an obesity-associated matricellular protein linked with muscular damage in genetic myopathies. THBS1 induces proliferation of fibro-adipogenic progenitors (FAPs) - mesenchymal cells that differentiate into adipocytes and fibroblasts. We hypothesized that THBS1 drives FAP-mediated diaphragm remodeling and contractile dysfunction in DIO. We tested this by comparing the effects of dietary challenge on diaphragms of wild-type (WT) and Thbs1-knockout (Thbs1-/-) mice. Bulk and single-cell transcriptomics demonstrated DIO-induced stromal expansion in WT diaphragms. Diaphragm FAPs displayed upregulation of ECM and TGF-β-related expression signatures and augmentation of a Thy1-expressing subpopulation previously linked to type 2 diabetes. Despite similar weight gain, Thbs1-/- mice were protected from these transcriptomic changes and from obesity-induced increases in diaphragm adiposity and ECM deposition. Unlike WT controls, Thbs1-/- diaphragms maintained normal contractile force and motion after DIO challenge. THBS1 is therefore a necessary mediator of diaphragm stromal remodeling and contractile dysfunction in overnutrition and a potential therapeutic target in obesity-associated respiratory dysfunction.

The extracellular matrix differentially directs myoblast motility and differentiation in distinct forms of muscular dystrophy

Extracellular matrix (ECM) pathologic remodeling underlies many disorders, including muscular dystrophy. Tissue decellularization removes cellular components while leaving behind ECM components. We generated “on-slide” decellularized tissue slices from genetically distinct dystrophic mouse models. The ECM of dystrophin- and sarcoglycan-deficient muscles had marked thrombospondin 4 deposition, while dysferlin-deficient muscle had excess decorin. Annexins A2 and A6 were present on all dystrophic decellularized ECMs, but annexin matrix deposition was excessive in dysferlin-deficient muscular dystrophy. Muscle-directed viral expression of annexin A6 resulted in annexin A6 in the ECM. C2C12 myoblasts seeded onto decellularized matrices displayed differential myoblast mobility and fusion. Dystrophin-deficient decellularized matrices inhibited myoblast mobility, while dysferlin-deficient decellularized matrices enhanced myoblast movement and differentiation. Myoblasts treated with recombinant annexin A6 increased mobility and fusion like that seen on dysferlin-deficient decellularized matrix and demonstrated upregulation of ECM and muscle cell differentiation genes. These findings demonstrate specific fibrotic signatures elicit effects on myoblast activity.

The cross talk between type II diabetic microenvironment and the regenerative capacities of human adipose tissue-derived pericytes: a promising cell therapy

BackgroundPericytes (PCs) are multipotent contractile cells that wrap around the endothelial cells (ECs) to maintain the blood vessel's functionality and integrity. The hyperglycemia associated with Type 2 diabetes mellitus (T2DM) was shown to impair the function of PCs and increase the risk of diabetes complications. In this study, we aimed to investigate the deleterious effect of the diabetic microenvironment on the regenerative capacities of human PCs.MethodsPCs isolated from human adipose tissue were cultured in the presence or absence of serum collected from diabetic patients. The functionality of PCs was analyzed after 6, 14, and 30 days.ResultsMicroscopic examination of PCs cultured in DS (DS-PCs) showed increased aggregate formation and altered surface topography with hyperbolic invaginations. Compared to PCs cultured in normal serum (NS-PCs), DS-PCs showed more fragmented mitochondria and thicker nuclear membrane. DS caused impaired angiogenic differentiation of PCs as confirmed by tube formation, decreased VEGF-A and IGF-1 gene expression, upregulated TSP1, PF4, actin-related protein 2/3 complex, and downregulated COL21A1 protein expression. These cells suffered more pronounced apoptosis and showed higher expression of Clic4, apoptosis facilitator BCl-2-like protein, serine/threonine protein phosphatase, and caspase-7 proteins. DS-PCs showed dysregulated DNA repair genes CDKN1A, SIRT1, XRCC5 TERF2, and upregulation of the pro-inflammatory genes ICAM1, IL-6, and TNF-α. Further, DS-treated cells also showed disruption in the expression of the focal adhesion and binding proteins TSP1, TGF-β, fibronectin, and PCDH7. Interestingly, DS-PCs showed resistance mechanisms upon exposure to diabetic microenvironment by maintaining the intracellular reactive oxygen species (ROS) level and upregulation of extracellular matrix (ECM) organizing proteins as vinculin, IQGAP1, and tubulin beta chain.ConclusionThese data showed that the diabetic microenvironment exert a deleterious effect on the regenerative capacities of human adipose tissue-derived PCs, and may thus have possible implications on the vascular complications of T2DM. Nevertheless, PCs have shown remarkable protective mechanisms when initially exposed to DS and thus they could provide a promising cellular therapy for T2DM.Graphical abstract

IMG-07. MOLECULAR PROCESSES GIVE RISE TO EMERGENCE OF RADIO-PHENOTYPES ON MRI SCANS OF PEDIATRIC LOW-GRADE GLIOMA

Abstract There is mounting evidence that tumor microenvironmental pressure selects for somatic genetic alterations that contribute to the formation of distinct morphological characteristics, captured on radiology scans as radio-phenotypes. Such phenotypic variations are a source of heterogeneity in clinical manifestation of tumors of the same histology across the patients, and in part, their heterogeneous responses to therapies. Deeper understanding of the associations between genotype and radio-phenotype in pediatric low-grade glioma (pLGG), the most histologically diverse childhood brain tumor, may facilitate precision diagnostic and therapeutic approaches. Here, we categorize pLGGs into distinct and relatively homogeneous imaging subtypes based on radiomic features and further explore the associations of these imaging subtypes with genotype. From multiparametric MRI scans of 167 pLGGs from the Children’s Brain Tumor Network (CBTN), 881 radiomic features and clinical variables (tumor location, age, and gender) were extracted. After dimensionality reduction using principal component analysis (PCA), K-Means clustering was applied on 19 principal components to group the patients into three imaging subtypes. Using whole transcriptomic data from OpenTargets, differential expression and co-expression of network- and pathway-level and immune-related signaling were compared among these three imaging subtypes. Gene Set Enrichment Analysis (GSEA) revealed differentially higher expression of cell cycle regulatory, extracellular matrix (ECM) remodeling, and cell migratory pathways in imaging subtype1 than subtypes 2 and 3, and upregulation of ECM and immune-related pathways in subtypes 1 and 2 compared to subtype3. Based on Gene Sets Net Correlations Analysis (GSNCA), subtype1 exhibited differential co-regulation of TNF/TNFR1 signaling compared to subtype2, and differential co-regulation of RHOG GTPase and TGFB1pathways when compared against subtype3. Subtype2 showed differential co-regulation in NOTCH1 signaling and transcriptional regulatory pathways. Our proposed multi-disciplinary radiomic-genomic analysis approach elucidates the molecular and biological processes in the genotype of the tumors that are associated with emergence of distinct imaging subtypes in pLGG.

Abstract 1116: Spatial distribution of granzyme B to improve the predictive power of response to immunotherapy in operable lung cancer

Abstract Purpose Non-small cell lung cancer (NSCLC) accounts for about 85% of all lung cancers. There is a strong rationale for incorporating immunotherapy into the treatment of early-stage NSCLC, given the breakthrough results with PD-1 checkpoint inhibitors in advanced-stage NSCLC. How immunotherapy should be implemented in patients who are operable is still unclear. Most of the efforts so far to identify clinically useful biomarkers do not preserve spatial information and leave us blind to the critical source of information revealed in the cell-to-cell biology of the tumor microenvironment (TME). In order to overcome these limitations, we used spatial biomarkers assays that preserve this critical information about which cells are influencing treatment response. Method Frozen sections from retrospectively collected surgically resected NSCLC (adenocarcinoma and squamous cell carcinoma) tumors treated with adjuvant pembrolizumab therapy were used. Patients were classified in two groups according to their Objective Response Rate (ORR): Complete Response (CR) and Progression Disease (PD) for spatial transcriptomic and proteomics assays. Associated to RNA In situ hybridization (ISH) technology, the NanoString GeoMx™ Digital Spatial Profiling (DSP) technology was used to determine immune markers within compartment specific defined by fluorescence localization [tumor (panCK) and leucocytes (CD45)]. Wilcoxon, Linear Mixed Model and Mann-Whitney U statistic tests were used to evaluate differences between ORR groups. Results Using the spatial analysis, we identified 4 protein markers from immune cell profiling and immune activation status modules independently associated with benefit from single-agent PD-1 checkpoint blockade in spatial context. High expression of CD4, CD40, Granzyme B and HLA-DR were significantly associated with all favorable clinical outcome, whereas upregulation of extracellular matrix (ECM) proteins related to pro-tumoral reprogramming of the stroma were associated with immunotherapy resistance. We also validated the DSP finding that high granzyme level in the stroma compartment was predictive for response to check point inhibitor in the same set of patients using ISH immunofluorescence, strengthening this marker relevance in antitumor immunity and as a predictive biomarker candidate for immunotherapy in NSCLC. Conclusion This work identifies a number of relevant spatial candidate predictors of immunotherapy outcome in spatial context for operable lung cancer that show promise for future validation in larger independent cohorts. Citation Format: Corinne Ramos, Ophelie Lemieux, Adele Ponzoni, Jonathan Stauber. Spatial distribution of granzyme B to improve the predictive power of response to immunotherapy in operable lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1116.

SPONTANEOUSLY HYPERTENSIVE RATS EXHIBIT ENHANCED CARDIAC CONNEXIN-43 AND REDUCED PRO-FIBROTIC MARKERS IN RESPONSE TO COLD ACCLIMATION

Objective: We have previously shown that down-regulation of myocardial gap junction channel protein, connexin-43 (Cx43), and up-regulation of extracellular matrix (ECM) proteins in hearts of spontaneously hypertensive rats (SHR) promote occurrence of lethal arrhythmia. Cold acclimation has a potential for reducing cardiovascular risk, especially in setting of various pathological conditions, but there is a gap of knowledge concern the heart response to adaptive thermogenesis. The purpose of the study is to explore myocardial Cx43 and ECM proteins in genetically hairless strain of SHR (SHRM) that represents rewarding model of increased adaptive thermogenesis. Design and method: Adult hairless males and females SHRM strain that harbors mutated desmoglein-4 gene and their wild type SHR were housed at standard 22 C (that is below thermo-neutrality for these animals) and 12:12 hour light: dark cycle. WKY control rats were used as reference normotensive strain. Heart samples of the left ventricular tissue from euthanatized rats were used for the proteomics of Cx43, protein kinases, which phosphorylates Cx43, and for ECM markers TGF-, SMAD2/3, MMP-2, collagen-1. Immunofluorescence detection of Cx43 was performed to examine its myocardial topology. Results: Cx43 protein and its phosphorylated status was reduced in males and females SHR vs WKY rat hearts. In contrast, adaptive thermogenesis resulted in increased both parameters in SHRM regardless the sex. Moreover, pathological topology of Cx43 attributed to its enhanced localization at lateral sides of the cardiomyocytes in SHR was attenuated in SHRM. In addition, there were gentle differences in protein levels of PKA, PKG, PKC, MAPK, Akt between SHR and SHRM. Protein level of TGF- and SMAD 2/3 were increased in SHR compare to WKY rat hearts but decreased in SHRM unlike collagen-1 that was not altered in SHRM compare to SHR. Conclusions: Findings revealed beneficial up-regulation of myocardial Cx43 along with down-regulation of extracellular matrix proteins in response of hairless SHR to increased thermogenesis.

High-Fat-Diet-Induced Extracellular Matrix Deposition Regulates Integrin-FAK Signals in Adipose Tissue to Promote Obesity.

High-fat-diet (HFD) is an important factor in obesity. Extracellular matrix (ECM) regulates white adipose tissue (WAT), but its mechanism is unknown. This study uses three models-HFD-fed mice, human with obesity, and 3T3-L1 adipocytes with oleic acid (OA)/macromolecular crowders (MMC) treatment. Glucose and lipids metabolic disorders, increased collagen I/IV and laminin α2/4 (LAMA2/4), and upregulated integrins (ITGA1/ITGA7) - focal adhesion kinase (FAK) - c-Jun N-terminal kinase (JNK)/extracellular regulated protein kinase 1/2 (ERK1/2) signals in obese WAT from mice and human are observed. The upregulation of ECM - integrin - FAK signals is stronger in subcutaneous WAT than that in visceral WAT of mice, but these results are reversed in human. In vitro, oleic acid (OA) promotes lipid accumulation and upregulates collagen IV, LAMA4, and p-JNK. MMC is used to induce ECM deposition in adipocytes. MMC promotes adipocyte differentiation and integrins - FAK - JNK/ERK1/2 signals. When FAK phosphorylation is inhibited, downstream p-JNK is decreased. Inhibition of FAK phosphorylation reduces adipocyte differentiation, but MMC partially reverses this effect. HFD-induced ECM deposition, whose signals are transmitted into adipocytes through upregulating ITGA1/ITGA7, activates the phosphorylation of intracellular FAK - JNK/ERK1/2 signals, and promotes adipogenesis in WAT. This mechanism provides novel therapeutic targets to treat obesity.

Silver sulfadiazine loaded core-shell airbrushed nanofibers for burn wound healing application

Ideal dressing materials for complex and large asymmetric burns should have the dual properties of anti-bacterial and regenerative with advanced applicability of direct deposit on the wound at the patient bedside. In this study, core-shell nanofibers (polycaprolactone; PCL and polyethylene oxide; PEO) with different percent of silver sulfadiazine (SSD) loading (2–10%) were prepared by the airbrushing method using a custom build device. Results indicate a sustained release profile of silver sulfadiazine (SSD) up to 28 days and concentration-dependent anti-bacterial activity. The morphology and proliferation of human dermal fibroblast (HDF) cells and human dental follicle stem cells (HDFSC) on the silver sulfadiazine loaded nanofibers confirm the biocompatibility of airbrushed nanofibers. Moreover, upregulation of extracellular matrix (ECM) proteins (Col I, Col III, and elastin) support the differentiation and regenerative properties of silver sulfadiazine nanofiber mats. This was further confirmed by the complete recovery of rabbit burn wound models within 7 days of silver sulfadiazine loaded nanofiber dressing. Histopathology data show silver sulfadiazine loaded core-shell nanofibers' anti-inflammatory and proliferative activity without any adverse response on the tissue. Overall data display that the airbrushed silver sulfadiazine-loaded core-shell nanofibers are effective dressing material with the possibility of direct fiber deposition on the wound to cover, heal, and regenerate large asymmetric burn wounds.

Collagen Content and Cross‐links Scale with Passive Stiffness in Dystrophic Mouse Diaphragm, but are not Altered with Administration of Collagen Cross‐linking Inhibitor Beta‐aminopropionitrile

In fibrotic skeletal muscle, such as that seen in Duchenne Muscular Dystrophy (DMD), there is upregulation of extracellular matrix (ECM) material, primarily collagen, and a severe change in muscle mechanics that often leads to contracture. Collagen cross-links, which can make the ECM stiffer, are increased in fibrotic models, such as the mdx mouse model of DMD. The objective of this study was to test the effects of cross-link inhibitor beta-aminopropionitrile (BAPN) on skeletal muscle ECM of wildtype (wt) and mdx mice. We hypothesized that BAPN treatment would reduce the amount of collagen cross-links and passive stiffness in skeletal muscle. Wt (N=9) and mdx (N=13) mice were given daily BAPN or phosphate-buffered saline (PBS) injections starting at 16-19 weeks of age for 4 weeks up to sacrifice. Soleus (SOL), extensor digitorum longus (EDL), and diaphragm (DP) muscles were collected for muscle active and passive mechanical measurement and imaged for collagen alignment data. Muscle collagen content and cross-linking were analyzed via hydroxyproline and collagen solubility assay. Across genotypes and muscles, BAPN treatment had no significant effects on collagen content or cross-links. Mdx mice showed reduced specific tension across muscles as expected (Fig 1A). The mdx DP had markedly higher dynamic stiffness than wt (+149%), without genotype differences in EDL and SOL, but BAPN increased stiffness in the mdx SOL (+100%) (Fig 1B). Total collagen content was increased across muscles in mdx mice, with the most dramatic effect again in the DP (+210%) compared to EDL (+62%) and SOL (+30%) (Fig 1C). Mdx mice also had significantly greater collagen cross-linking in DP (+9.3%) and EDL (+38%) muscles as measured by collagen solubility (Fig 2A). The dynamic stiffness of DP muscles was significantly related to total collagen content (R2 = 0.25) (Fig 1D), and cross-linking index of solubility also significantly scaled with dynamic stiffness across the DP (R2=0.19) (Fig 2B). BAPN treatment increased orientation index, a measure for collagen alignment, in wt SOL (+162%), but did not have any other effects on alignment. Orientation index was significantly increased in mdx EDL and SOL compared to wt (EDL: +76%; SOL: +45%), but not in the DP (Fig 2C). Dynamic stiffness across all muscles was significantly related to orientation index (R2 = 0.06), but this relationship was not significant in the DP (Fig 2D). These data show that the relationship between passive muscle stiffness and collagen is muscle-dependent. The DP had the strongest relationships with more collagen and cross-linking related to increased stiffness across conditions while also being the most fibrotic muscle. However, collagen alignment in the DP was not related to stiffness, implicating other factors contributing to stiffness in fibrosis. Overall, administration of BAPN had little or no impact on muscle stiffness, collagen content, cross-linking, and collagen alignment. Thus, the delivery or action of BAPN was not effective in reducing collagen cross-links within muscle.

Gene Expression Profiles Reveal Extracellular Matrix and Inflammatory Signaling in Radiation-Induced Premature Differentiation of Human Fibroblast in vitro.

PurposeFibroblasts are considered to play a major role in the development of fibrotic reaction after radiotherapy and premature radiation-induced differentiation has been proposed as a cellular basis. The purpose was to relate gene expression profiles to radiation-induced phenotypic changes of human skin fibroblasts relevant for radiogenic fibrosis.Materials and MethodsExponentially growing or confluent human skin fibroblast strains were irradiated in vitro with 1–3 fractions of 4 Gy X-rays. The differentiated phenotype was detected by cytomorphological scoring and immunofluorescence microscopy. Microarray analysis was performed on Human Genome U133 plus2.0 microarrays (Affymetrix) with JMP Genomics software, and pathway analysis with Reactome R-package. The expression levels and kinetics of selected genes were validated with quantitative real-time PCR (qPCR) and Western blotting.ResultsIrradiation of exponentially growing fibroblast with 1 × 4 Gy resulted in phenotypic differentiation over a 5-day period. This was accompanied by downregulation of cell cycle-related genes and upregulation of collagen and other extracellular matrix (ECM)-related genes. Pathway analysis confirmed inactivation of proliferation and upregulation of ECM- and glycosaminoglycan (GAG)-related pathways. Furthermore, pathways related to inflammatory reactions were upregulated, and potential induction and signaling mechanisms were identified. Fractionated irradiation (3 × 4 Gy) of confluent cultures according to a previously published protocol for predicting the risk of fibrosis after radiotherapy showed similar downregulation but differences in upregulated genes and pathways.ConclusionGene expression profiles after irradiation of exponentially growing cells were related to radiation-induced differentiation and inflammatory reactions, and potential signaling mechanisms. Upregulated pathways by different irradiation protocols may reflect different aspects of the fibrogenic process thus providing a model system for further hypothesis-based studies of radiation-induced fibrogenesis.

Activated KCNQ1 channel promotes fibrogenic response in hereditary gingival fibromatosis via clustering and activation of Ras.

Activated potassium channels were found to be strongly correlated with gingival overgrowth (GO) phenotype as we reviewed syndromic hereditary gingival fibromatosis (HGF). Nevertheless, the functional roles of potassium channels in gingival fibrosis or gingival overgrowth remained uncovered. The aim of the present study was to explore the pathogenic role of aberrantly activated potassium channel in Hereditary Gingival Fibromatosis (HGF). Gingival tissues were collected from 9 HGF patients and 15 normal controls. Expression of KCNQ1 was detected by immunohistochemistry. Gingival fibroblasts were isolated, and outward K+ currents were detected by whole-cell patch-clamp analysis, transmembrane potential was determined by flow cytometry. Normal human gingival fibroblasts (NHGFs) were transfected with KCNQ1 adenovirus or treated with KCNQ1 selective agonist ML277 and antagonist chromanol 293B. Accumulation of Extracellular Matrix (ECM) was measured by Western blotting and Sircol Soluble Collagen Assay. Content of secreted TGF-β1 was measured by ELISA. Active RAS pull-down assay and cell immunofluorescence were utilized to verify RAS activation. KCNQ1 was upregulated in gingival tissues derived from HGF patients and HGF gingival fibroblasts presented increased outward K+ currents than NHGFs. Overexpression of KCNQ1, or KCNQ1 agonist ML277, promoted fibrotic responses of NHGFs. TGF-β1 and KCNQ1 channels formed a positive feed-back loop. ML277 generated lateral clustering and activation of Ras on plasma membrane, followed by augmented MAPK/AP-1 signaling pathway output. JNK or ERK1/2 inhibitors suppressed ML277-induced AP-1 and ECM upregulation. Activation of KCNQ1 potassium channel promoted fibrogenic responses in NHGFs via Ras/MAPK/AP-1 signaling.

Schwann Cells Contribute to Alveolar Bone Regeneration by Promoting Cell Proliferation.

The plasticity of Schwann cells (SCs) following nerve injury is a critical feature in the regeneration of peripheral nerves as well as surrounding tissues. Here, we show a pivotal role of Schwann cell-derived cells in alveolar bone regeneration through the specific ablation of proteolipid protein 1 (Plp)-expressing cells and the transplantation of teased nerve fibers and associated cells. With inducible Plp specific genetic tracing, we observe that Plp+ cells migrate into wounded alveolar defect and dedifferentiate into repair SCs. Notably, these cells barely transdifferentiate into osteogenic cell lineage in both SCs tracing model and transplant model, but secret factors to enhance the proliferation of alveolar skeletal stem cells (aSSCs). As to the mechanism, this effect is associated with the upregulation of extracellular matrix (ECM) receptors and receptor tyrosine kinases (RTKs) signaling and the downstream extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) pathway and the phosphoinositide 3-kinase-protein kinase B (PI3K-Akt) pathway. Collectively, our data demonstrate that SCs dedifferentiate after neighboring alveolar bone injury and contribute to bone regeneration mainly by a paracrine function. © 2022 American Society for Bone and Mineral Research (ASBMR).

47 Burn-induced Ileal Extracellular Matrix Upregulation Associated with Epithelial to Mesenchymal Transition

Abstract Introduction Severe burns have long been associated with systemic inflammation and intestinal dysfunction. Recent evidence suggests that intestinal fibrosis may be responsible for intestinal dysfunction after burns. In response to inflammatory stimuli, intestinal epithelial cells may undergo epithelial-mesenchymal transition (EMT). EMT is a process by which epithelial cells acquire a mesenchymal-like phenotype, thereby compromising epithelial barrier function. EMT has been implicated in the pathogenesis of intestinal fibrosis. In the present study, we examined the cellular mechanism of burn-induced intestinal dysfunction. Methods Male BALA/c mice (8–12 weeks) received 30% total body surface area full-thickness scald burns or sham procedure. Ileal tissue was collected 5 days after burn for immunofluorescence (IF) and Western blot. Rat intestinal epithelial cell line IEC-6 was treated with cytokines and EMT marker proteins were analyzed by Western blot. Results IF data demonstrated that burn significantly increased extracellular matrix (ECM) protein laminin in ileal tissues, suggesting that burn injury induces ileal fibrogenesis. In IEC-6 cells treated with Tumor necrosis factor (TNF) α, IL-1β dose-dependently upregulated α-smooth muscle actin (α-SMA), a well known marker for myofibroblasts. ECM proteins fibronectin and laminin were found to be significantly increased after TNFα treatment. Tight junction protein E-cadherin was decreased after TNFα treatment. Futhermore, TNF receptor signaling antagonist R-7050 and SM7368 blocked TNFα-induced α-SMA upregulation. Conclusions Burn-induced mouse ileum ECM upregulation may be through TNFα-mediated EMT. Applicability of Research to Practice TNFα receptor antagonism could represent a potential pathway for drug development for treatment of burn-induced intestinal dysfunction.

TMEM45A is involved in renal fibrosis in rats by regulating Jagged1/Notch pathway.

Fibrosis, or the excess deposition of fibrous tissue, is a critical feature of chronic kidney disease. Here, using renal fibrotic rat as a model, which was established via 5/6 nephrectomy (Nx), the role of TMEM45A transmembrane protein in renal fibrosis was investigated. The results indicated that 5/6 Nx gradually led to histopathological abnormalities and loss of kidney function in rats, which correlated with upregulation of TMEM45A and Notch1. Interestingly, in NRK-49F renal cells, overexpression of TMEM45A resulted in up-regulation of extracellular matrix (ECM) components as well as induction of Notch-1 and Jagged-1. These effects were weakened by DAPT, an inhibitor of the Notch pathway, suggesting an important role of Notch signaling in mediating the functions of TMEM45A in NRK-49F cells Moreover, TMEM45A knockdown by TMEM45A siRNA in NRK-49F cells diminished TGF-b1-induced upregulation of ECM components, inflammatory cytokines, Notch-1 and Jagged-1. Correspondingly, TGF-beta 1 exhibited pro-fibrogenic like effect in NRK-49F cells and induced TMEM45A and Jagged1/Notch expression. Collectively, these results demonstrate that TMEM45A plays an important role in renal fibrosis by regulating ECM components and Jagged1/Notch pathway.

Serum extracellular vesicles contain SPARC and LRG1 as biomarkers of colon cancer and differ by tumour primary location.

BackgroundRecently, the distinction between left- and right-sided colon cancer (LCC and RCC) has been brought into focus. RCC is associated with an inferior overall survival and progression-free survival. We aimed to perform a detailed analysis of the diversity of extracellular vesicles (EV) between LCC and RCC using quantitative proteomics and to identify for new diagnostic and prognostic biomarkers.MethodsWe isolated EVs from patients with LCC, RCC and healthy volunteers, and treated colorectal cancer cell line with serum-derived EVs. We then performed a quantitative proteomics analysis of the serum-derived EVs and cell line treated with EVs. Proteomic data are available via ProteomeXchange with the identifiers PXD012283 and PXD012304. In addition, we assessed the performance of EV SPARC and LRG1 as diagnosis and prognosis biomarkers in colon cancer.FindingsThe expression profile of the serum EV proteome in patients with RCC was different from that of patients with LCC. Serum-derived EVs in RCC promoted cellular mobility more significantly than EVs derived from LCC. EV SPARC and LRG1 expression levels demonstrated area under the receiver-operating characteristic curve values of 0.95 and 0.93 for discriminating patients with colon cancer from healthy controls. Moreover, the expression levels of SPARC and LRG1 correlated with tumour sidedness and were predictive of tumour recurrence.InterpretationWe identified differences in EV protein profiles between LCC and RCC. Serum-derived EVs of RCC may promote metastasis via upregulation of extracellular matrix (ECM)-related proteins, especially SPARC and LRG1, which may serve as diagnosis and prognosis biomarkers in colon cancer.

Abstract 415: Electrical Stimulation of Pediatric Cardiac-derived c-kit + Progenitor Cells Improves Retention and Cardiac Function in Right Ventricular Heart Failure

Nearly 1% of babies born in the US will be diagnosed with a congenital heart defect (CHD). While surgical therapy has improved survival, many of these children go on to develop right ventricular heart failure (RVHF). The emergence of cardiovascular regenerative medicine as a potential therapeutic strategy for pediatric HF has provided new avenues for treatment with a focus on repairing or regenerating the diseased myocardium to restore cardiac function. While primarily tried using adult cells and adult disease models, stem cell therapy is relatively untested in the pediatric population. Cardiac-derived c-kit + progenitor cells (CPCs) have been widely studied as a cell-based therapy for cardiac pathologies; however, unless these cells are extracted at a very young age their therapeutic efficacy has been shown to be diminished. Finding novel ways to enhance the reparative potential of these cells is thus of critical significance. We previously reported pediatric CPCs (isolated from patients between 1-5 years of age) respond to electrical stimulation (ES) by initiating intracellular calcium oscillations. Here, we investigate the ability of ES to enhance the retention and therapeutic function of pediatric CPCs in an animal model of RVHF. Human CPCs isolated from pediatric patients were exposed to chronic ES and implanted into the RV myocardium of rats. Cardiac function and cellular retention analysis showed electrically stimulated CPCs (ES-CPCs) were retained in the heart at a significantly higher level and longer time than control CPCs and also significantly improved right ventricular functional parameters. ES also induced upregulation of extracellular matrix and adhesion genes, such as integrins β1 and β5, and significantly increased in vitro survival and adhesion of cells. Lastly, we show that ES induces CPCs to release higher levels of reported pro-reparative factors in vitro, including angiogenin, FGF, HGF, and VEGF. These findings suggest electrical stimulation can be utilized to increase the retention, survival, and therapeutic effect of human c- kit + progenitor cells. Furthermore, our insights into the mechanisms of increased retention and paracrine function of ES-CPCs can have implications on a variety of cell-based therapies.

Elevated H3K27ac in aged skeletal muscle leads to increase in extracellular matrix and fibrogenic conversion of muscle satellite cells.

Epigenetic alterations occur in various cells and tissues during aging, but it is not known if such alterations are also associated with aging in skeletal muscle. Here, we examined the changes of a panel of histone modifications and found H3K27ac (an active enhancer mark) is markedly increased in aged human skeletal muscle tissues. Further analyses uncovered that the H3K27ac increase and enhancer activation are associated with the up‐regulation of extracellular matrix (ECM) genes; this may result in alteration of the niche environment for skeletal muscle stem cells, also called satellite cells (SCs), which causes decreased myogenic potential and fibrogenic conversion of SCs. In mice, treatment of aging muscles with JQ1, an inhibitor of enhancer activation, inhibited the ECM up‐regulation and fibrogenic conversion of SCs and restored their myogenic differentiation potential. Altogether, our findings not only uncovered a novel aspect of skeletal muscle aging that is associated with enhancer remodeling but also implicated JQ1 as a potential treatment approach for restoring SC function in aging muscle.

UPARANT is an effective antiangiogenic agent in a mouse model of rubeosis iridis

Puncture-induced iris neovascularization (rubeosis iridis; RI) in mice is associated with upregulation of extracellular matrix (ECM) degradation and inflammatory factors. The anti-angiogenic and anti-inflammatory efficacy of UPARANT in reducing RI was determined by noninvasive, in vivo iris vascular densitometry, and confirmed in vitro by quantitative vascular-specific immunostaining. Intravitreal administration of UPARANT successfully and rapidly reduced RI to non-induced control levels. Molecular analysis revealed that UPARANT inhibits formyl peptide receptors through a predominantly anti-inflammatory response, accompanied with a significant reduction in ECM degradation and inflammation markers. Similar results were observed with UPARANT administered systemically by subcutaneous injection. These data suggest that the tetrapeptide UPARANT is an effective anti-angiogenic agent for the treatment of RI, both by local and systemic administrations. The effectiveness of UPARANT in reducing RI in a model independent of the canonical vascular endothelial growth factor (VEGF) proposes an alternative for patients that do not respond to anti-VEGF treatments, which could improve treatment in proliferative ocular diseases.Key messagesUPARANT is effective in the treatment of rubeosis iridis, both by local and systemic administrations.UPARANT can reduce VEGF-independent neovascularization.

Bardoxolone ameliorates TGF-β1-associated renal fibrosis through Nrf2/Smad7 elevation

Transforming growth factor-β (TGF-β) is a potent pathogenic factor of renal injury through the upregulation of extracellular matrix (ECM) expression and facilitation of renal fibrosis. Nuclear factor erythroid 2-like 2 (Nfe2l2; Nrf2), a master regulator of antioxidant and detoxifying systems, is mainly controlled by the binding with cytosolic protein Kelch-like ECH-associated protein 1 (Keap1) and subsequent proteasomal degradation. The protective effect of Nrf2 on renal injury has been attributed to its antioxidant role, where it aids in coping with oxidative stress-associated progression of renal disease. In this study, we investigated the effect of Nrf2 activation on ECM production and TGF-β/Smad signaling using Keap1-silenced MES-13 cells (a genetic glomerular mesangial cell model with Nrf2 overexpression). The TGF-β1-inducible expression of fibronectin and α-smooth muscle actin (α-Sma) was suppressed and Smad2/3 phosphorylation was blocked in Nrf2-high mesangial cells as compared with that in control cells. Notably, in these Nrf2-high mesangial cells, levels of TGF-β1 receptor 1 (TβR1) were substantially diminished, and the protein levels of Smad7, an inhibitor TGF-β1/Smad signaling, were increased. Nrf2-mediated Smad7 elevation and its anti-fibrotic role in Keap1-silenced cells were confirmed by studies with Nrf2-or Smad7-silencing. As a molecular link for Smad7 elevation in Nrf2-high cells, the reduction of Smad-ubiquitination-regulatory factor 1 (Smurf1), an E3 ubiquitin ligase for Smad7, was notable. Silencing of Smurf1 increased Smad7 in the control mesangial cells; however, forced expression of Smurf1 repressed Smad7 levels in Keap1-silenced cells. Additionally, we demonstrate that bardoxolone (BARD; CDDO-methyl), a pharmacological activator of Nrf2, increased Smad7 levels and attenuated TGF-β/Smad/ECM expression in MES-13. Moreover, in an aristolochic acid (AA)-mediated nephropathy mouse model, the renal expression of Nrf2 and Smad7 was elevated by BARD treatment, and AA-induced tubular necrosis and interstitial fibrosis were substantially ameliorated by BARD. Collectively, these results indicate that the Nrf2-Smad7 axis plays a key role in the protection of TGF-β-induced renal fibrosis, and further suggest a novel molecular mechanism of beneficial effect of BARD on renal disease.

Metabolic regulation of dermal fibroblasts contributes to skin extracellular matrix homeostasis and fibrosis.

Extracellular matrix (ECM) homeostasis is essential for normal tissue function, and its disruption by iatrogenic injury, trauma, or disease results in fibrosis. Skin ECM homeostasis is maintained by a complex process that involves an integration of cytokine and environmental mediators. However, it is unclear, in both normal and disease states, how these multifactorial processes converge to shift ECM homeostasis towards accumulation or degradation. Here we show a consistent downregulation in fatty acid oxidation (FAO) and upregulation of glycolysis in fibrotic skin and in normal skin with abundant ECM. Perturbation of glycolysis and FAO pathway enzymes reveals their reciprocal effects in ECM upregulation and downregulation, respectively. Increasing peroxisome proliferator-activated receptor (PPAR) signalling, an inducer of the FAO pathway, generates a catabolic fibroblast phenotype characterised by inhibition of ECM transcription and enhanced ECM internalization and lysosomal degradation. In contrast, suppression of glycolysis inhibits ECM gene transcription and protein levels, independently of an intact FAO pathway or PPAR signalling. Moreover, we show that CD36, a multifunctional fatty acid transporter, connects the metabolic state of fibroblasts with their capacity for ECM regulation, as internalization and degradation of collagen-1 is abrogated in fibroblasts lacking CD36. Finally, restoring FAO and upregulating CD36 reduces ECM accumulation in murine skin fibrosis. These findings indicate that metabolic perturbation of ECM homeostasis may have broad implications for therapies aimed at ECM regulation, such as fibrosis, regenerative medicine, and ageing.