Myofibroblast-like Cells Research Articles

Helicobacter pylori Infection-Induced Hepatoma-Derived Growth Factor Regulates the Differentiation of Human Mesenchymal Stem Cells to Myofibroblast-Like Cells.

Hepatoma-derived growth factor (HDGF) plays a critical role in tumor cell proliferation, anti-apoptosis, VEGF expression, lymph node metastasis and poor prognosis in human gastric cancer. Gastric cancer, as one of the most prevalent cancers worldwide, is the second leading cause of cancer-related mortality in the world for the prognosis of gastric cancer is generally poor, especially in patients with advanced stage. Helicobacter pylori (H. pylori) infection causes the chronic inflammation of stomach as well as the development of gastric cancer, with a three to six-fold increased risk of gastric cancer. Carcinoma-associated fibroblasts (CAFs) are myofibroblasts in tumor microenvironment, which possess various abilities to promote the progression of cancer by stimulating neoangiogenesis, proliferation, migration, invasion and therapy resistance of tumor cell. Mesenchymal stem cells (MSCs) are reported to promote tumor malignance through differentiation of MSCs toward CAFs. In the present study, we demonstrated that H. pylori infection promotes HDGF expression in human gastric cancer cells. HBMMSCs treated with HDGF assume properties of CAF-like myofibroblastic phenotypes, including expression of myofibroblast markers (α-smooth muscle actin (α-SMA), procollagen α1, tropomyoson I, desmin, fibroblast activation protein (FAP)), and fibroblast markers (prolyl-4-hydroxylase A1 (PHA1) and fibroblast specific protein-1 (FSP-1)/S100A4). HDGF recruits HBMMSCs, and then HBMMSCs further contributes to cell survival and invasive motility in human gastric cancer cells. Treatment of HDGF neutralizing antibody (HDGF-NAb) and serum significantly inhibit HDGF-regulated differentiation and recruitment of HBMMSCs. These findings suggest that HDGF might play a critical role in gastric cancer progress through stimulation of HBMMSCs differentiation to myofibroblast-like cells.

57 - Aerobic glycolysis is necessary for smooth muscle to myofibroblast transition in response to PDGF

Atherosclerosis is the most prevalent cause of death across the world. Numerous clinical studies have concluded that decreased plaque stability, not greater lesion size, is a better determinant of rupture and adverse thrombotic events with unstable plaques being characterized by a high ratio of macrophages to smooth muscle cells (SMCs) and little ECM deposition. During the development of atherosclerotic lesions, SMCs from the arterial wall proliferate and migrate to form a protective fibrous cap. This cap is composed of ACTA2+ SMCs and myofibroblast-like cells of undetermined origin, which secrete collagen to maintain a lesion-stabilizing extracellular matrix. Using SMC-lineage tracing mice, our lab and others have shown that SMCs undergo phenotypic transitions during atherosclerosis, fundamentally changing into myofibroblasts, macrophage-like cells, and others. After exposure to mitogens such as platelet-derived growth factor (PDGF), SMCs undergo de-differentiation causing marker genes such as Acta2 to be downregulated while collagen genes are upregulated. SMCs rely on oxidative phosphorylation to provide energy for contraction, but the energetic requirement for SMCs to undergo a phenotypic transition to a myofibroblast-like cell is not well understood. Thus, we hypothesized that fibrogenic and mitogenic stimuli force a metabolic shift in SMCs, necessary to energetically support a phenotypic transition to an atheroprotective myofibroblast-like state. Using extracellular flux analysis, we found that cultured SMCs significantly increase their capacity for aerobic glycolysis in response to PDGF and transforming growth factor-β (TGFβ). Furthermore, pharmacologically inhibiting lactate dehydrogenase, using galloflavin, not only prevents PDGF-induced aerobic glycolysis, but also abrogates PDGF-driven downregulation of Acta2. Additionally, galloflavin abrogates PDGF-induced expression of collagen genes. We conclude that a metabolic shift to aerobic glycolysis is necessary for SMCs to undergo a phenotypic transition to a myofibroblast state, and suggest that modifying SMC metabolism represents a previously undiscovered mechanism for strengthening the fibrous cap and stabilizing atherosclerotic lesions.

Retinoids Issued from Hepatic Stellate Cell Lipid Droplet Loss as Potential Signaling Molecules Orchestrating a Multicellular Liver Injury Response.

Hepatic stellate cells (HSCs) serve as the main body storage compartment for vitamin A through retinyl ester (RE)-filled lipid droplets (LDs). Upon liver injury, HSCs adopt a myofibroblastic phenotype characterized by an elevated expression of extracellular matrix proteins and a concomitant loss of LDs. On the one hand, LD breakdown has been suggested to provide the energy required for HSC activation into myofibroblast-like cells. On the other hand, this process could mitigate HSC activation following the transformation of released REs into retinoic acids (RAs), ligands for nuclear receptors exerting antifibrotic transcriptional regulatory activities in HSCs. Importantly, RAs may also constitute a means for HSCs to orchestrate the liver response to injury by triggering transcriptional effects in multiple additional surrounding liver cell populations. We envision that new approaches, such as single-cell technologies, will allow to better define how RAs are issued from LD loss in HSCs exert a multicellular control of the liver (patho)physiology.

Chrysin Inhibits Advanced Glycation End Products-Induced Kidney Fibrosis in Renal Mesangial Cells and Diabetic Kidneys.

Advanced glycation end products (AGEs) play a causative role in the development of diabetic nephropathy via induction of matrix protein deposition in kidneys. This study investigated inhibitory effects of chrysin, present in bee propolis and herbs, on glomerulosclerosis in db/db mice and AGEs-exposed renal mesangial cells. The in vivo study explored the demoting effects of 10 mg/kg chrysin on glomerular fibrosis in a type 2 diabetic model. Oral supplementation of chrysin inhibited the collagen fiber accumulation and α-smooth muscle actin (α-SMA) induction in periodic acid schiff-positive renal tissues of db/db mice. Moreover, treating db/db mice with chrysin diminished the level of AGEs increased in diabetic glomeruli. The in vitro study employed human mesangial cells exposed to 100 μg/mL AGE-BSA for 72 h in the presence of 1–20 μM chrysin. Glucose increased mesangial AGE production via induction of receptor for AGEs. Chrysin suppressed the induction of collagens, α-SMA, fibroblast-specific protein-1 and matrix metalloproteinases enhanced by AGE-bovine serum albumin. Furthermore, chrysin blunted transforming growth factor-β1 induction and Smad 2/3 activation in AGEs-exposed mesangial cells. These results demonstrate that chrysin attenuated accumulation of myofibroblast-like cells and matrix proteins in AGEs-laden diabetic glomeruli. Therefore, chrysin may be a potential renoprotective agent targeting glucose-mediated AGEs-associated glomerulosclerosis and fibrosis.

The Role of Adipocyte Fatty Acid Binding Protein in the Development of Liver Fibrosis

Liver fibrosis is the result of chronic liver injury and the first step toward the development of liver cirrhosis and hepatic carcinoma. Under the stress of damage factors, quiescent hepatic stellate cells (qHSCs) trans-differentiate into myofibroblast-like cells, and take the main role of extracellular matrix secretion contributing to the development of liver fibrosis. In recent clinical study, circulating level of A-FABP, was found to positively correlate with the stages of liver fibrosis and liver cirrhosis. Here, we investigate the role of A-FABP in the development of liver fibrosis. A-FABP knockout (A-FABP KO) mice and their wild type (WT) littermates were subjected to bile duct ligation (BDL) for two weeks to induce liver fibrosis. Plasma and hepatic A-FABP were significantly elevated in BDL treated WT mice. Liver sinusoidal endothelial cell (LSEC) was identified as the major cellular source of hepatic A-FABP in response to BDL. In the BDL treated groups, comparing to the WT mice, A-FABP KO mice showed significantly reduced collagen formation and HSC activation which were accompanied by an attenuated induction of hepatic expression of transforming growth factor beta 1 (TGFβ1), a central regulator in hepatic fibrogenesis. As the LSECs and HSCs are closely attached to each other, we hypothesize that LSECs-derived A-FABP may act in a paracrine manner to stimulate the expression of TGFβ1 in HSCs. Our in vitro study demonstrated that treatment of recombinant A-FABP protein (rA-FABP) significantly induced the expression of TGFβ1 in primary HSCs. Mechanistically, BDL induces the release of A-FABP from LSECs which stimulates the TGFβ1 gene transcription through enhancing the activator protein-1 (AP-1) activity on its promoter via upregulating the phosphorylation of c-Jun, a component of AP-1. In conclusion, A-FABP contributes to the development of liver fibrosis via enhancing the expression of TGFβ1 in HSCs. Disclosure X. Wu: None. L. Shu: None. K.S. Lam: None. A. Xu: None. R. Hoo: None.

A Rising Star in Pancreatic Diseases: Pancreatic Stellate Cells.

Pancreatic stellate cell (PSC) is a type of pluripotent cell located between pancreatic lobules and the surrounding area of acinars. When activated, PSC can be transformed into myofibroblast-like cell. A number of evidences suggest that activated PSC is the main source of the accumulation of extracellular matrix (ECM) protein under the pathological conditions, which lead to pancreatic fibrosis in chronic pancreatitis and pancreatic cancer. Recent studies have found that PSC also plays an important role in the endocrine cell function, islet fibrosis and diabetes. In order to provide new strategies for the treatment of pancreatic diseases, this paper systematically summarizes the recent researches about the biological behaviors of PSC, including its stem/progenitor cell characteristics, secreted exosomes, cellular senescence, epithelial mesenchymal transformation (EMT), energy metabolism and direct mechanical reprogramming.

Cardiac fibrosis can be attenuated by blocking the activity of transglutaminase 2 using a selective small-molecule inhibitor

Cardiac fibrosis is implicit in all forms of heart disease but there are no effective treatments. In this report, we investigate the role of the multi-functional enzyme Transglutaminase 2 (TG2) in cardiac fibrosis and assess its potential as a therapeutic target. Here we describe the use a highly selective TG2 small-molecule inhibitor to test the efficacy of TG2 inhibition as an anti-fibrotic therapy for heart failure employing two different in vivo models of cardiac fibrosis: Progressively induced interstitial cardiac fibrosis by pressure overload using angiotensin II infusion: Acutely induced focal cardiac fibrosis through myocardial infarction by ligation of the left anterior descending coronary artery (AMI model). In the AMI model, in vivo MRI showed that the TG2 inhibitor 1–155 significantly reduced infarct size by over 50% and reduced post-infarct remodelling at 20 days post insult. In both models, Sirius red staining for collagen deposition and levels of the TG2-mediated protein crosslink ε(γ-glutamyl)lysine were significantly reduced. No cardiac rupture or obvious signs of toxicity were observed. To provide a molecular mechanism for TG2 involvement in cardiac fibrosis, we show that both TGFβ1-induced transition of cardiofibroblasts into myofibroblast-like cells and TGFβ1-induced EndMT, together with matrix deposition, can be attenuated by the TG2 selective inhibitor 1–155, suggesting a new role for TG2 in regulating TGFβ1 signalling in addition to its role in latent TGFβ1 activation. In conclusion, TG2 has a role in cardiac fibrosis through activation of myofibroblasts and matrix deposition. TG2 inhibition using a selective small-molecule inhibitor can attenuate cardiac fibrosis.

A humanized mouse model of liver fibrosis following expansion of transplanted hepatic stellate cells

Hepatic stellate cells (HSCs) are major contributors to liver fibrosis, as hepatic injuries may cause their transdifferentiation into myofibroblast-like cells capable of producing excessive extracellular matrix proteins. Also, HSCs can modulate engraftment of transplanted hepatocytes and contribute to liver regeneration. Therefore, understanding the biology of human HSCs (hHSCs) is important, but effective methods have not been available to address their fate in vivo. To investigate whether HSCs could engraft and repopulate the liver, we transplanted GFP-transduced immortalized hHSCs into immunodeficient NOD/SCID mice. Biodistribution analysis with radiolabeled hHSCs showed that after intrasplenic injection, the majority of transplanted cells rapidly translocated to the liver. GFP-immunohistochemistry demonstrated that transplanted hHSCs engrafted alongside hepatic sinusoids. Prior permeabilization of the sinusoidal endothelial layer with monocrotaline enhanced engraftment of hHSCs. Transplanted hHSCs remained engrafted without relevant proliferation in the healthy liver. However, after CCl4 or bile duct ligation-induced liver damage, transplanted hHSCs expanded and contributed to extracellular matrix production, formation of bridging cell-septae and cirrhosis-like hepatic pseudolobules. CCl4-induced injury recruited hHSCs mainly to zone 3, whereas after bile duct ligation, hHSCs were mainly in zone 1 of the liver lobule. Transplanted hHSCs neither transdifferentiated into other cell types nor formed tumors in these settings. In conclusion, a humanized mouse model was generated by transplanting hHSCs, which proliferated during hepatic injury and inflammation, and contributed to liver fibrosis. The ability to repopulate the liver with transplanted hHSCs will be particularly significant for mechanistic studies of cell-cell interactions and fibrogenesis within the liver.

Adjunct Targeted Biologic Inhibition Agents to Treat Aggressive Multivessel Intraluminal Pediatric Pulmonary Vein Stenosis

To evaluate the use of imatinib mesylate with or without bevacizumab targeting neoproliferative myofibroblast-like cells with tyrosine kinase receptor expression, as adjuncts to modern interventional therapies for the treatment of multivessel intraluminal pulmonary vein stenosis (PVS). We describe the 48- and 72-week outcomes among patients receiving imatinib mesylate with or without bevacizumab for multivessel intraluminal PVS. This single-arm, prospective, open-label US Food and Drug Administration approved trial enrolled patients with ≥2 affected pulmonary veins after surgical or catheter-based relief of obstruction between March 2009 and December 2014. Drug therapy was discontinued at 48 weeks, or after 24 weeks of stabilization, whichever occurred later. Among 48 enrolled patients, 5 had isolated PVS, 26 congenital heart disease, 5 lung disease, and 12 both. After the 72-week follow-up, 16 patients had stabilized, 27 had recurred locally without stabilization, and 5 had progressed. Stabilization was associated with the absence of lung disease (P = .03), a higher percentage of eligible drug doses received (P = .03), and was not associated with age, diagnosis, disease laterality, or number of veins involved. Survival to 72 weeks was 77% (37 of 48). Adverse events were common (n = 1489 total), but only 16 were definitely related to drug treatment, none of which were serious. Survival to 72 weeks was 77% in a referral population with multivessel intraluminal PVS undergoing multimodal treatment, including antiproliferative tyrosine kinase blockade. Toxicity specific to tyrosine kinase blockade was minimal.

Increased Substrate Stiffness Elicits a Myofibroblastic Phenotype in Human Lamina Cribrosa Cells.

Alteration in the extracellular matrix (ECM) of the optic nerve head (ONH) causes lamina cribrosa (LC) fibrosis and affects the mechanical integrity of the ONH. Increased ECM tissue stiffness drives myofibroblast activation leading to tissue fibrosis throughout the body. Here using primary human LC cells, we investigate the effect of substrate stiffness on profibrotic changes, which might be a key molecular mechanism driving ECM remodeling of the LC in primary open-angle glaucoma (POAG) glaucoma. Primary human LC cells from normal and age-matched POAG glaucoma donors were cultured on substrates with defined mechanical properties of 5 and 100 kPa to replicate the range of mechanical microenvironments that cells may experience in vivo. Cell morphology, spread area, actin stress fibers, vinculin-focal adhesion formation, and α-smooth muscle actin (α-SMA) signal were examined using immunofluorescence staining. The elastic modulus of cells was measured using atomic force microscopy (AFM). Significantly greater cell spread area along with increased actin filament development, and vinculin-focal adhesion formation (number and size) were found in both normal and glaucoma LC cells cultured on stiff substrates. These changes were positively associated with elevated cell stiffness measured by AFM. Changes in spreading and cytoskeleton organization of glaucoma LC cells were significantly more pronounced than those in normal cells. The transformation to a myofibroblast-like cell phenotype was identified in both LC cells exposed to stiffer substrates, as indicated by an increased α-SMA signal and its colocalization with the actin stress fibers. These findings demonstrated that a stiffer cell microenvironment activates a myofibroblastic transformation in human LC cells, and therefore contributes to LC remodelling and fibrosis in glaucoma.

Hamartoma fibroso de la infancia umbilical: Reporte de un caso

Introduction: Fibrous hamartoma of infancy (FHI) is a benign, soft tissue tumor that usually occurs in children and has a characteristic histological morphology. Objective: To describe a case of congenital FHI with atypical histological and clinical characteristics. Clinical case: Full-term male newborn, with no perinatal morbid history was referred to dermatology due to a congenital erythematous plaque in the umbilical region. The histological study showed a fusocelullar proliferation in dermis and hypodermis of biphasic distribution, with an infiltrative, swirling pattern and bundles of spindle fibroblast-like and myofibroblast-like cells, associated in depth with a mature adipose tissue component. The immunohistochemical study revealed diffuse positivity for CD34, and focal positivity for FXIIIa, without immunoreactivity for actin, desmin, MyoD1, S100, HMB45, Melan-A, or EMA. Fluorescent in situ hybridization (FISH) was negative for platelet-derived growth factor receptor beta (PDGFR-beta) and for ETV6 gene. PDGFR-beta and ETV6 gene are present in congenital dermatofibrosarcoma protuberans and infantile fibrosarcoma, respectively. This history, in addition to previous histological findings, supported the diagnosis of FHI. Surgical resection was performed, without signs of recurrence during clinical follow-up. Conclusion: It is important to consider the FHI within the differential diagnosis of subcutaneous tumors in children, especially in those under two years of age. Although its behavior is benign, it is similar to multiple benign and malignant lesions, which makes it imperative to perform a histological study in front of suspicious clinical lesions.

Development and characterization of human iPSC-derived myofibroblast-like cells

Development and characterization of human iPSC-derived myofibroblast-like cells

Improving the biological function of decellularized heart valves through integration of protein tethering and three-dimensional cell seeding in a bioreactor.

Decellularized xenogeneic heart valves (DHVs) are promising products for valve replacement. However, the widespread clinical application of such products is limited due to the risk of immune reaction, progressive degeneration, inflammation, and calcification. Here, we have developed an optimized decellularization protocol for a xenogeneic heart valve. We improved the biological function of DHVs by protein tethering onto DHV and three-dimensional (3D) cell seeding in a bioreactor. Our results showed that heart valves treated with a Triton X-100 and sodium deoxycholate-based protocol were completely cell-free, with preserved biochemical and biomechanical properties. The immobilization of stromal derived factor-1α (SDF-1α) and basic fibroblast growth factor on DHV significantly improved recellularization with endothelial progenitor cells under the 3D culture condition in the bioreactor compared to static culture conditions. Cell phenotype analysis showed higher fibroblast-like cells and less myofibroblast-like cells in both protein-tethered DHVs. However, SDF-DHV significantly enhanced recellularization both in vitro and in vivo compared to basic fibroblast growth factor DHV and demonstrated less inflammatory cell infiltration. SDF-DHV had less calcification and platelet adhesion. Altogether, integration of SDF-1α immobilization and 3D cell seeding in a bioreactor might provide a novel, promising approach for production of functional heart valves.

Stromal Lkb1 deficiency leads to gastrointestinal tumorigenesis involving the IL-11-JAK/STAT3 pathway.

Germline mutations in the gene encoding tumor suppressor kinase LKB1 lead to gastrointestinal tumorigenesis in Peutz-Jeghers syndrome (PJS) patients and mouse models; however, the cell types and signaling pathways underlying tumor formation are unknown. Here, we demonstrated that mesenchymal progenitor- or stromal fibroblast-specific deletion of Lkb1 results in fully penetrant polyposis in mice. Lineage tracing and immunohistochemical analyses revealed clonal expansion of Lkb1-deficient myofibroblast-like cell foci in the tumor stroma. Loss of Lkb1 in stromal cells was associated with induction of an inflammatory program including IL-11 production and activation of the JAK/STAT3 pathway in tumor epithelia concomitant with proliferation. Importantly, treatment of LKB1-defcient mice with the JAK1/2 inhibitor ruxolitinib dramatically decreased polyposis. These data indicate that IL-11-mediated induction of JAK/STAT3 is critical in gastrointestinal tumorigenesis following Lkb1 mutations and suggest that targeting this pathway has therapeutic potential in Peutz-Jeghers syndrome.

Upregulation of the actin cytoskeleton via myocardin leads to increased expression of type 1 collagen

Liver fibrosis, a model wound healing system, is characterized by excessive deposition of extracellular matrix (ECM) in the liver. Although many fibrogenic cell types may express ECM, the hepatic stellate cell (HSC) is currently considered to be the major effector. HSCs transform into myofibroblast-like cells, also known as hepatic myofibroblasts in a process known as activation; this process is characterized in particular by de novo expression of smooth muscle alpha actin (SM α-actin) and type 1 collagen. The family of actins, which form the cell's cytoskeleton, are essential in many cellular processes. β-actin and cytoplasmic γ-actin (γ-actin) are ubiquitously expressed, whereas SM α-actin defines smooth muscle cell and myofibroblast phenotypes. Thus, SM α-actin is tightly associated with multiple functional properties. However, the regulatory mechanisms by which actin isoforms might regulate type 1 collagen remain unclear. In primary HSCs from normal and fibrotic rat liver, we demonstrate that myocardin, a canonical SRF cofactor, is upregulated in hepatic myofibroblasts and differentially regulates SM α-actin, γ-actin, and β-actins through activation of an ATTA box in the SM α-actin and a CCAAT box in γ-actin and β-actin promoters, respectively; moreover, myocardin differentially activated serum response factor (SRF) in CArG boxes of actin promoters. In addition, myocardin-stimulated Smad2 phosphorylation and RhoA expression, leading to increased expression of type 1 collagen in an actin cytoskeleton-dependent manner. Myocardin also directly enhanced SRF expression and stimulated collagen 1α1 and 1α2 promoter activities. In addition, overexpression of myocardin in vivo during carbon tetrachloride-induced liver injury led to increased HSC activation and fibrogenesis. In summary, our data suggest that myocardin plays a critical role in actin cytoskeletal dynamics during HSC activation, in turn, specifically regulating type I collagen expression in hepatic myofibroblasts.

Ultrastructural analyses of internal limiting membrane excised from highly myopic eyes with myopic traction maculopathy.

To evaluate the ultrastructure of the internal limiting membranes (ILMs) excised during vitrectomy from highly myopic eyes with myopic traction maculopathy (MTM). The clinical findings before and after the vitrectomy were compared. Seven eyes of 7 patients with macular retinoschisis were studied. Four of these eyes also had a foveal detachment but without a retinal break. All the eyes underwent vitrectomy with the creation of a posterior vitreous detachment and ILM peeling. The excised ILMs were examined by transmission electron microscopy (TEM). The retinas were reattached in all eyes after the vitrectomy. No retinal breaks including macular holes were identified intraoperatively. Transmission electron microscopy showed glial cells in 4 eyes, retinal pigment epithelium-like cells in 4 eyes, and myofibroblast-like cells in 4 eyes on the excised ILMs. A newly produced basement membrane appeared to merge with the ILM in 5 eyes. Thick collagen was seen in 2 eyes, and fibrous long-spacing collagen in the newly synthesized collagen fibers was seen in 3 eyes. The cellular components of the glial cells appeared to have migrated through the thinner parts of the retina or through a defect of the ILM in 2 eyes. Cells that migrate onto the surface of the ILM synthesize new collagen, which can create tangential traction. This may explain the success of vitrectomy with ILM peeling in treating MTM in highly myopic eyes.

Induced pluripotent stem cell-conditioned medium suppresses pulmonary fibroblast-to-myofibroblast differentiation via the inhibition of TGF-β1/Smad pathway.

Therapeutic strategies based on stem cells have been shown to have potential in improving the condition of severe lung diseases. In this study, the suppressive effects of conditioned medium (CM) of induced pluripotent stem cells (iPSCs) on pulmonary fibroblast differentiation were investigated in a series of in vitro and in vivo experiments. Moreover, the underlying mechanisms through which iPSC-CM inhibited the differentiation of fibroblasts into myofibroblasts were explored as well. iPSCs were generated using a mouse 3-gene transfection method, myofibroblast-like cells were induced by incubating human fibroblasts with transforming growth factor-β1 (TGF-β1) and mouse models of pulmonary fibrosis (PF) were established by an injection of bleomycin. Based on these experiments, the effects of iPSC-CM on collagen accumulation, lung structure and the TGF-β1-mediated pathway were determined. It was found that treatment with iPSC-CM markedly reduced the proliferation of TGF-β1-exposed cells, and the activities of TGF-β1, Smad-2 and Smad-3. Accompanied by alterations in the expression of the indicated molecules, the lung structure of mice with PF was also markedly ameliorated. The present study confirmed the protective effects of iPSC-CM on lung tissue against PF, and it was also inferred that the ameliorating function of iPSC-CM on PF may be exerted through the blocking of TGF-β1/Smad signal transduction pathway.

The functional relationship between transglutaminase 2 and transforming growth factor \u03b21 in the regulation of angiogenesis and endothelial\u2013mesenchymal transition

The importance of transglutaminase 2 (TG2) in angiogenesis has been highlighted in recent studies, but other roles of this multi-functional enzyme in endothelial cell (EC) function still remains to be fully elucidated. We previously showed that the extracellular TG2 is involved in maintaining tubule formation in ECs by a mechanism involving matrix-bound vascular endothelial growth factor (VEGF) signalling. Here, by using the ECs and fibroblast co-culture and ECs 3D culture models, we demonstrate a further role for TG2 in both endothelial tubule formation and in tubule loss, which involves its role in the regulation of transforming growth factor β1 (TGFβ1) and Smad signalling. We demonstrate that inhibition of tubule formation by TG2 inhibitors can be restored by add-back of exogenous TGFβ1 at pg/ml levels and show that TG2 −/− mouse ECs are unable to form tubules in 3D culture and display negligible Smad signalling compared to wild-type cells. Loss of tubule formation in the TG2 −/− ECs can be reconstituted by transduction with TG2. We demonstrate that extracellular TG2 also has an important role in TGFβ1-induced transition of ECs into myofibroblast-like cells (endothelial–mesenchymal transition), resulting in loss of EC tubules and tubule formation. Our data also indicate that TG2 may have a role in regulating TGFβ signalling through entrapment of active TGFβ1 into the extracellular matrix. In conclusion, our work demonstrates that TG2 has multi-functional roles in ECs where its ability to fine-tune of TGFβ1 signalling means it can be involved in both endothelial tubule formation and tubule rarefaction.

CREB3L2-mediated expression of Sec23A/Sec24D is involved in hepatic stellate cell activation through ER-Golgi transport

Hepatic fibrosis is caused by exaggerated wound healing response to chronic injury, which eventually leads to hepatic cirrhosis. Differentiation of hepatic stellate cells (HSCs) to myofibroblast-like cells by inflammatory cytokines is the critical step in fibrosis. This step is accompanied by enlargement of the endoplasmic reticulum (ER) and Golgi apparatus, suggesting that protein synthesis and secretion are augmented in the activated HSCs. However, the process of rearrangement of secretory organelles and their functions remain to be fully elucidated. Here, we revealed that differentiation alters early secretory gene expression. We observed significant isoform-specific upregulation of the inner coat protein complex II (COPII) components, Sec23A and Sec24D, via the transmembrane bZIP transcription factor, CREB3L2/BBF2H7, during HSC activation. Moreover, knockdown of these components abrogated the activation, suggesting that Sec23A/Sec24D-mediated ER to Golgi trafficking is required for HSC activation.

Antifibrotic effects of cyclosporine A on TGF-β1-treated lung fibroblasts and lungs from bleomycin-treated mice: role of hypoxia-inducible factor-1α.

Idiopathic pulmonary fibrosis (IPF) is a chronic lung disorder that is characterized by aberrant tissue remodeling and the formation of fibroblastic foci that are composed of fibrogenic myofibroblasts. TGF-β1 is one of the factors that are responsible for fibrosis as it promotes fibroblast to myofibroblast differentiation (FMD) and is associated with up-regulation of α-smooth muscle actin. Therefore, inhibition of FMD may represent an effective strategy for the treatment of IPF. Here, we describe the treatment of human lung fibroblasts (WI-38 and HFL-1 cells) with cyclosporine A (CsA), which reduces TGF-β1-induced FMD via degradation of hypoxia-inducible factor-1α (HIF-1α). In addition, in primary myofibroblast-like cells that were obtained from a patient with pulmonary fibrosis, treatment with CsA and an HIF-1α inhibitor (HIFi) decreased the expression levels of α-smooth muscle actin and fibronectin, which indicated that CsA and HIFi promote dedifferentiation of myofibroblasts. In mice intratracheally administered CsA or HIFi at an early fibrotic stage [7, 8, and 9 d postinstillation (dpi) of bleomycin], marked alleviation of lung fibrosis was observed at 14 dpi. These results suggest that CsA exhibits antifibrotic effects by degrading HIF-1α and that the CsA-HIF-1α axis provides new insights into therapeutic options for the treatment of IPF.-Yamazaki, R., Kasuya, Y., Fujita, T., Umezawa, H., Yanagihara, M., Nakamura, H., Yoshino, I., Tatsumi, K., Murayama, T. Antifibrotic effects of cyclosporine A on TGF-β1-treated lung fibroblasts and lungs from bleomycin-treated mice: role of hypoxia-inducible factor-1α.