Myofibroblast Marker Research Articles

The epigenetic regulator BRD4 is required for myofibroblast differentiation of knee fibroblasts.

Arthrofibrosis, which is characterized by excessive scar tissue and limited motion, can complicate the daily functioning of patients after total knee arthroplasty (TKA). Molecular hallmarks of arthrofibrosis include pathologic accumulation of myofibroblasts and disproportionate collagen deposition. Epigenetic mechanisms, including posttranslation modification of histones, control gene expression and may regulate fibrotic events. This study assessed the role of the bromodomain and extra-terminal (BET) proteins on myofibroblast differentiation. This group of epigenetic regulators recognize acetylated lysines and are targeted by a class of drugs known as BET inhibitors. RNA-seq analysis revealed robust mRNA expression of three BET members (BRD2, BRD3, and BRD4) while the fourth member (BRDT) is not expressed in primary TKA knee outgrowth fibroblasts. RT-qPCR and western blot analyses revealed that BET inhibition with the small molecule JQ1 impairs TGFβ1-induced expression of ACTA2, a key myofibroblast marker, in primary outgrowth knee fibroblasts. Similarly, JQ1 administration also reduced COL3A1 mRNA levels and collagen deposition as monitored by picrosirius red staining. Interestingly, the inhibitory effects of JQ1 on ACTA2 mRNA and protein expression, as well as COL3A1 expression and collagen deposition, were paralleledby siRNA-mediated depletion of BRD4. Together, these data reveal that BRD4-mediated epigenetic events support TGFβ1-mediated myofibroblast differentiation and collagen deposition as seen in arthrofibrosis. To our knowledge, these are the first studies that assess epigenetic regulators and their downstream events in the context of arthrofibrosis. Future studies may reveal clinical utility for drugs that target epigenetic pathways, specifically BET proteins, in the prevention and treatment of arthrofibrosis.

Cepharanthine Ameliorates Pulmonary Fibrosis by Inhibiting the NF-κB/NLRP3 Pathway, Fibroblast-to-Myofibroblast Transition and Inflammation.

Pulmonary fibrosis (PF) is one of the sequelae of Corona Virus Disease 2019 (COVID-19), and currently, lung transplantation is the only viable treatment option. Hence, other effective treatments are urgently required. We investigated the therapeutic effects of an approved botanical drug, cepharanthine (CEP), in a cell culture model of transforming growth factor-β1 (TGF-β1) and bleomycin (BLM)-induced pulmonary fibrosis rat models both in vitro and in vivo. In this study, CEP and pirfenidone (PFD) suppressed BLM-induced lung tissue inflammation, proliferation of blue collagen fibers, and damage to lung structures in vivo. Furthermore, we also found increased collagen deposition marked by α-smooth muscle actin (α-SMA) and Collagen Type I Alpha 1 (COL1A1), which was significantly alleviated by the addition of PFD and CEP. Moreover, we elucidated the underlying mechanism of CEP against PF in vitro. Various assays confirmed that CEP reduced the viability and migration and promoted apoptosis of myofibroblasts. The expression levels of myofibroblast markers, including COL1A1, vimentin, α-SMA, and Matrix Metallopeptidase 2 (MMP2), were also suppressed by CEP. Simultaneously, CEP significantly suppressed the elevated Phospho-NF-κB p65 (p-p65)/NF-κB p65 (p65) ratio, NOD-like receptor thermal protein domain associated protein 3 (NLRP3) levels, and elevated inhibitor of NF-κB Alpha (IκBα) degradation and reversed the progression of PF. Hence, our study demonstrated that CEP prevented myofibroblast activation and treated BLM-induced pulmonary fibrosis in a dose-dependent manner by regulating nuclear factor kappa-B (NF-κB)/ NLRP3 signaling, thereby suggesting that CEP has potential clinical application in pulmonary fibrosis in the future.

A Modified Suture Technique to Improve Scar Appearance in Wounds Under High Tension.

The purpose of this study was to introduce a modified suture technique and to compare its effects on skin scar formation with 2 traditional suture methods: simple interrupted suture (SIS) and vertical mattress suture (VMS). Three groups of healthy adult female Sprague-Dawley rats were selected (6 replicates in each group), and the full-thickness skin of 5 cm × 0.2 cm was cut off on the back of the rats after anesthesia. The wounds were then sutured using 1 of the 3 methods for each group: SIS, VMS, and a newly introduced modified vertical mattress suture (M-VMS) technique with the needle reinsertion at the exit point. A traction device was installed on the back of the rats to achieve high tension wounds. The tensile distance was increased by 1 mm every day for 20 days. After 20 days of healing, the hematoxylin-eosin staining method was used for observation of scar morphology. The collagen production rate was measured by Masson staining, and the type I collagen and type III collagen were detected by the immunofluorescence method. Immunohistochemical staining was used to detect the expression of myofibroblast marker α-smooth muscle actin, and real-time quantitative polymerase chain reaction and Western blot techniques were used to detect the expressions of transforming growth factors TGFβ1, TGFβ2, and TGFβ3 to understand the mechanisms of scar formation. Results showed that the quantity and density of collagen fibers were both lower in the M-VMS group than in the other 2 groups. Immunofluorescence results showed that type I collagen was significantly lower, whereas type III collagen was significantly higher in the M-VMS group than in the other 2 groups. The expressions of α-smooth muscle actin and TGFβ1 both were lower in the M-VMS group than in the other 2 groups. The expression of TGFβ2 and TGFβ3 had no obvious difference among the 3 groups. For wounds under high tension, compared with SIS and VMS methods, the M-VMS technique we proposed can reduce scar formation due to the reduction of collagen formation, myofibroblast expression, and TGFβ1 expression.

Neuron-Glial Antigen 2 Participates in Liver Fibrosis via Regulating the Differentiation of Bone Marrow Mesenchymal Stem Cell to Myofibroblast

Neuron-glial antigen 2 (NG2, gene name: Cspg4) has been characterized as an important factor in many diseases. However, the pathophysiological relevance of NG2 in liver disease specifically regarding bone marrow mesenchymal stem cell (BMSC) differentiation to myofibroblast (MF) and the molecular details remain unknown. Human liver tissues were obtained from patients with different chronic liver diseases, and mouse liver injury models were induced by feeding a methionine-choline-deficient and high-fat diet, carbon tetrachloride administration, or bile duct ligation operation. NG2 expression was increased in human and mouse fibrotic liver and positively correlated with MF markers α-smooth muscle actin (αSMA) and other fibrotic markers in the liver. There was a co-localization between NG2 and αSMA, NG2 and EGFP (BMSC-derived MF) in the fibrotic liver determined by immunofluorescence analysis. In vitro, TGFβ1-treated BMSC showed a progressive increase in NG2 levels, which were mainly expressed on the membrane surface. Interestingly, there was a translocation of NG2 from the cell membrane into cytoplasm after the transfection of Cspg4 siRNA in TGFβ1-treated BMSC. siRNA-mediated inhibition of Cspg4 abrogated the TGFβ1-induced BMSC differentiation to MF. Importantly, inhibition of NG2 in vivo significantly attenuated the extent of liver fibrosis in methionine-choline-deficient and high fat (MCDHF) mice, as demonstrated by the decreased mRNA expression of fibrotic parameters, collagen deposition, serum transaminase levels, liver steatosis and inflammation after the administration of Cspg4 siRNA in MCDHF mice. We identify the positive regulation of NG2 in BMSC differentiation to MF during liver fibrosis, which may provide a promising target for the treatment of liver disease.

Notch Blockade Specifically in Bone Marrow-Derived FSP-1-Positive Cells Ameliorates Renal Fibrosis

The infiltration of inflammatory cells during a kidney injury stimulates myofibroblast activation leading to kidney fibrosis. Fibroblast-specific protein 1 (FSP-1) positive cells have been reported as either myofibroblasts or monocytes during tissue fibrosis. The functions of FSP-1+ cells that are associated with the development of renal fibrosis and the signaling pathways that regulate FSP-1+ cell activation have not been well defined. In mice with unilateral ureteral obstruction (UUO), we characterized FSP-1+ cells and determined the role of the Notch signaling pathway in the activation of bone marrow-derived FSP-1+ cells during kidney fibrosis. In kidneys from mice with UUO, the FSP-1+ cells accumulated significantly in the tubulointerstitial area. By using immunostaining and FSP-1 reporter mice, we found that FSP-1 was co-stained with inflammatory cell markers, but not myofibroblast markers. Results from mice with bone marrow transplantations showed that FSP-1+ cells in obstructed kidneys represent a bone marrow-derived population of inflammatory cells. In cultured FSP-1+ cells, the inhibition of Notch signaling suppressed the activation and cytokine secretion of FSP-1+ cells that were induced by LPS but not by IL-4. The specific KO or blockade of Notch signaling in bone marrow-derived FSP-1+ cells suppressed UUO-induced ECM deposition, the infiltration of FSP-1+ inflammatory cells, and cytokine production. These responses ameliorated myofibroblast accumulation and renal fibrosis in obstructed kidneys. Our study reveals that most FSP-1+ cells in obstructed kidneys are activated macrophages that are derived from bone marrow and that Notch signaling activates the production of M1 cytokines in FSP-1+ monocytes/macrophages, which is important for renal inflammation and fibrosis.

PS-B03-10: EPLERENONE INHIBITS ICAM-1 FROM MACROPHAGES AND MACROPHAGE-TO-MYOFIBROBLAST TRANSITION IN TYPE 4 CARDIORENAL SYNDROME RATS INDUCED WITH UUO

Objective: The type 4 cardiorenal syndrome (CRS) represents the kidney-heart relationship in a pathological situation where cardiovascular complications dominate all causes of death in patients with chronic kidney disease (CKD), but the underlying mechanism of CKD-induced cardiac disease have not been fully clarified. We reported that aldosterone directly stimulates cardiac fibrosis, whereas macrophage-to-myofibroblast (MMT) is associated with fibrosis. However, the mechanistic basis of this pathogenic pathway that promotes cardiac fibrosis remains to be elucidated. Design and method: We used a 180-day rat model of unilateral ureteral obstruction (UUO) to replicate the CRS model and RAW264.7 cells in-vitro studies. Using eplerenone, a blocker of mineralocorticoid receptor (MR), to test the effect of aldosterone in cardiac fibrosis induced by UUO. The levels of intercellular adhesion molecule (ICAM)-1 and monocyte chemoattractant protein (MCP)-1 were examined to verify the role of macrophage infiltration and inflammatory injury. Co-expression of macrophage marker CD68 and myofibroblast marker -SMA to identify MMT contributing to cardiac fibrosis. Results: We identified cardiac injury in UUO rats, and eplerenone can inhibit UUO-induced cardiac fibrosis. We found that macrophages can co-express the myofibroblast marker alpha-SMA for phenotypic transformation and participate in cardiac fibrosis by secreting collagen III, while eplerenone inhibits this process. Activated MR enhanced macrophage infiltration and secretion of ICAM-1 and MCP-1, which stimulated inflammatory injury in the heart, whereas aldosterone stimulation and eplerenone treatment with RAW264.7 revealed a role for aldosterone in cardiac fibrosis. Conclusions: Our results identified the role of aldosterone in promoting macrophage infiltration and MMT through MR/SGK-1 pathway. These findings provide a new mechanism for macrophage involvement in the pathogenesis of UUO-induced cardiac fibrosis and reveal novel therapeutic targets.

PS-B01-7: VASCULAR SMOOTH MUSCLE CELL NOX5 REGULATES FIBROBLAST PHENOTYPIC SWITCH AND CARDIOVASCULAR FIBROSIS

Objective: We previously observed that mice expressing human Nox5 (hNox5) in VSMC exhibit vascular dysfunction and cardio-renal fibrosis, where mechanisms are unknown. Here we postulated that VSMC-Nox5 promotes fibroblast phenotypic changes leading to myofibroblast differentiation and pro-fibrotic responses. Design and Methods: Fibroblasts were cultured from wildtype (WT) and hNOX5 mice (Nox5 + SM22 +). Mice (20 weeks old) were infused with Ang II (600 ng/Kg/day) for 28 days and renal fibrosis/inflammation studied. Markers of myofibroblasts, pro-fibrotic and inflammatory phenotypes were assessed by qPCR and immunoblotting. Results: Fibroblasts from Nox5 + SM22 + mice exhibited increased mRNA of pro-fibrotic markers, such as Col1A1 (2-ddC:1.74 ± 0.16 vs. WT 0.67 ± 0.11), Col3A1 (2-ddC:1.74 ± 0.18 vs. WT 0.96 ± 0.24) and TIMP3 (2-ddC:2.65 ± 0.25 vs. WT 0.38 ± 0.07), p < 0.05. Myofibroblast phenotype (SMC) markers mRNA, aSMA (2-ddC:1.54 ± 0.05 vs. WT 0.78 ± 0.17) and Myocd (2-ddC:1.36 ± 0.17 vs. WT 0.39 ± 0.22) were also increased, p < 0.05. mRNA expression of CD36 (2-ddC:1.37 ± 0.07 vs. WT 86 ± 0.24), TNFa (2-ddC:1.32 ± 0.2 vs. WT 0.71 ± 0.17) and TNFR1 (2-ddC:1.26 ± 0.04 vs. WT 1.02 ± 0.10) were increased, while CD68 expression was decreased (2-ddC:0.82 ± 0.11 vs. WT 1.36 ± 0.18) in fibroblasts from Nox5+SM22+ mice (p < 0.05). In Nox5 mice fibroblasts, ROS production and TGFb protein expression (AU:1.8 ± 0.05 vs. WT 1.4 ± 0.06), as well as TGFbR2 gene expression (2-ddC:2.04 ± 0.17 vs. WT 0.57 ± 0.12), were increased (p < 0.05). Kidneys from Ang II-infused Nox5+SM22+ mice exhibited significant perivascular fibrosis and inflammatory cell infiltration compared to WT. Kidney expression of vimentin (AU:1.01 ± 0.05 vs WT 0.85 ± 0.03) and aSMA (AU:0.44 ± 0.03 vs WT 0.33 ± 0.01), markers of myofibroblast differentiation, were increased in Nox5 mice (p < 0.05). Gene expression of DNMT3a and TET2, DNA methylation regulatory enzymes, were also increased in fibroblasts from Nox5+SM22+ mice, p < 0.05. Conclusion: VSMC-Nox5 regulates fibroblast phenotypic switch leading to fibrosis; a process that may involve increased production of ROS and TGFb, and activation of DNA methylation pathways.

Modulating Myofibroblastic Differentiation of Fibroblasts through Actin-MRTF Signaling Axis by Micropatterned Surfaces for Suppressed Implant-Induced Fibrosis.

Myofibroblasts, the primary effector cells for implant-induced fibrosis, contribute to this process by secreting excessive collagen-rich matrix and contracting. Thus, approaches that suppress myofibroblasts may achieve desirable suppression effects in the fibrotic process. As one of the important physical properties of materials, material topographical structures have been proven to affect various aspects of cell behaviors, so is it possible to manipulate the formation of myofibroblasts by tailoring the topographical properties of medical devices? In this study, polycaprolactone (PCL) surfaces with typical micropatterns (micro column and micro pit) were fabricated. The regulatory effects of surface micropatterns on the myofibroblastic differentiation of fibroblasts were investigated. Compared to the flat surfaces and surfaces with micro pit, surfaces with micro columns triggered the F- to G-actin transition, inhibiting the nuclear transfer of myocardin-related transcription factor-A. Subsequently, the downstream gene α-smooth muscle actin, which is a marker of myofibroblasts, was suppressed. Further in vivo investigation showed that PCL implants with micro-column-patterned surfaces inhibited the formation of peri-implant fibrotic capsules. Our results demonstrate that surface topographical properties are a potent regulator of fibroblast differentiation into myofibroblasts and highlight the antifibrotic potential of modifying surfaces with micro-column patterns.

PS-B12-1: EPLERENONE INHIBITS UUO-INDUCED LYMPHANGIOGENESIS AND CARDIAC FIBROSIS BY ATTENUATING INFLAMMATORY INJURY

Objective: Cardiorenal syndrome (CRS) is the leading cause of death associated with chronic kidney disease (CKD) and end-stage renal disease (ESRD), however, the underlying mechanism of CKD-induced cardiac injury is incompletely understood. We reported that aldosterone is associated with cardiac fibrosis, and that inflammatory injury and lymphangiogenesis are involved. This pathogenic mechanism CKD-induced cardiac fibrosis still needs further investigation. Design and method: The unilateral ureteral obstruction (UUO) model was used to replicate the CRS type 4 model. Following induction of renal injury, the rats received eplerenone for 180-day. For in-vitro studies, we exposed human lymphatic endothelial cells (hLEC) to aldosterone and eplerenone. Changes in cardiac tissue related to lymphangiogenesis and inflammatory were analyzed in vivo. Changes in lymphangiogenesis, LEC phenotypic transformation and activation of mineralocorticoid receptor (MR)/ transforming growth factor (TGF)-beta/ vascular endothelial growth factor C (VEGFC) signaling axis involved in these changes were analyzed in vivo and in vitro. Results: We found that eplerenone ameliorated cardiac inflammation and fibrosis in UUO rats. Moreover, eplerenone inhibited MR activation, attenuated lyphangiogenesis and LEC phenotypic transformation, and regulated TGF-beta/CTGF/VEGFC signaling axis in vivo and in vitro. The levels of podoplanin, VEGFR-3 and VEGFC confirmed the role of lymphangiogenesis and inflammatory injury. Co-expression of LEC marker LYVE-1 and myofibroblast marker alpha-SMA validated EndMT in cardiac fibrosis. Treatment with eplerenone, clarified the role of aldosterone in UUO-induced cardiac fibrosis. Conclusions: We confirmed that eplerenone can alleviate UUO-induced cardiac fibrosis by inhibiting inflammation and lymphangiogenesis via MR/TGF-beta/VEGFC signaling axis. These findings provide an in-depth understanding of pathogenesis of UUO-induced cardiac injury and reveal novel therapeutic targets.

Single-cell transcriptome analysis identifies Versican(+) myofibroblast as a hallmark for thoracic aortic aneurysm marked by activation of PI3K-AKT signaling pathway

BackgroundThoracic aortic aneurysm (TAA) is a silent but dangerous cardiovascular disease. Understanding molecular mechanisms of TAA on single-cell level might provide new strategies for preventing and treating TAA. MethodsSingle-cell RNA sequencing was performed on control and aneurysmal thoracic aorta to find out specific cell clusters and cell types. Western blot and histological staining were used to verify the findings of single-cell transcriptome analysis. Characteristics of Versican (VCAN) overexpressed myofibroblast was evaluated through bioinformatic methods and experimental validation. ResultsA total of 3 control and 8 TAA specimens were used for single-cell transcriptome analysis including 48,128 thoracic aortic cells. Among these cells, we found out a specific cell cluster containing both hallmarks of smooth muscle cell (SMC) and fibroblast. Thus, we defined these cells as myofibroblast. Further single-cell transcriptome analysis identified VCAN as a cellular marker of myofibroblast. Western blot and histological staining revealed that VCAN(+) myofibroblast was significantly increased in TAA specimens compared with control individuals. Differential analysis, functional, pathway enrichment analysis and cell-cell communication analysis demonstrated that VCAN(+) myofibroblast was closely associated with previous reported TAA associated pathological process including SMC proliferation, SMC migration and extracellular matrix (ECM) disruption. Pathway analysis found out significant activation of PI3K-AKT signaling pathway within VCAN(+) myofibroblast, which was further confirmed by experimental validation. ConclusionsSingle-cell RNA sequencing identified VCAN(+) myofibroblast as a typical cellular hallmark of TAA. These cells might participate in the pathogenesis of TAA through activation of PI3K-AKT signaling pathway to link SMC proliferation, SMC migration and ECM disruption.

Crosstalk between myofibroblasts and macrophages: A regulative factor of valvular fibrosis in calcific aortic valve disease

Inflammation and fibrosis are highly correlated with the progression of calcific aortic valve disease (CAVD). As one of the differentiated forms of valvular interstitial cells, myofibroblasts play a critical role in CAVD's development as do macrophages. Although numerous studies have been conducted on them separately, their communication and interaction remain unclear. We used porcine aortic valves to isolate valve interstitial cells (VICs). VICs were induced to differentiate into myofibroblasts by transforming growth factor-β1 (TGF-β1). After successful activation was determined, the myofibroblast-conditioned medium (CM) was collected and used to act on RAW264.7, a macrophage cell line. A migration and adhesion assay estimated the recruitment capability of myofibroblasts on macrophages. We used flow cytometry, quantitative polymerase chain reaction (qPCR), and Western blot analysis to investigate myofibroblasts' polarity promotion function in macrophages. Finally, we used macrophage-CM on VICs to explore the differentiation induction function of polarized macrophages. Myofibroblast marker alpha-smooth muscle actin and M2 macrophage marker CD163 were detected as upregulated in CAVD patients, and their expression has a certain correlation. The Smad3/HA/CD44 axis activated the differentiation of myofibroblasts by Western blot. The myofibroblast-CM can promote chemotaxis and adhesion of macrophages through protein kinase B/chemokine (C-C motif) ligand5 and Smad3/HA/CD44, respectively. Hyaluronic acid (HA) inside the myofibroblast-CM stimulates macrophages to polarize into M2 macrophages. In turn, M2 macrophage-CM has the promotive ability to activate myofibroblasts but fails to induce the osteoblast differentiation of VICs directly. The crosstalk between myofibroblasts and macrophages causes the excessive activation of myofibroblasts. This positive feedback loop may play a vital role in CAVD progression.

Induction of premature senescence and a less-fibrogenic phenotype by programmed cell death 4 knockdown in the human hepatic stellate cell line Lieming Xu-2

Although programmed cell death 4 (PDCD4) was initially reported as a tumor suppressor and has been shown to inhibit cancer cell growth and metastasis, recent studies have demonstrated that loss of PDCD4 expression also induces growth inhibition by inducing apoptosis and/or cellular senescence. At present, the roles of PDCD4 in the activation and profibrogenic properties of myofibroblasts, which are critically involved in organ fibrosis, such as that in the liver, are unclear. We, therefore, investigated the roles of PDCD4 in myofibroblasts using human hepatic stellate cell line Lieming Xu-2 (LX-2). PDCD4 knockdown inhibited LX-2 proliferation and induced a senescent phenotype with increased β-galactosidase staining and p21 expression in a p53-independent manner together with downregulation of the notch signaling mediator RBJ-κ/CSL. During PDCD4 knockdown, alpha smooth muscle actin (α-SMA; an activation marker of myofibroblasts), matrix metalloproteinases MMP-1 and MMP-9, and collagen IV were upregulated, but the expression of collagen1α1 and collagen III was markedly downregulated without any marked change in the expression of tissue inhibitor of metalloproteinase-1 (TIMP-1). These results demonstrated that knockdown of PDCD4 induced the cellular senescence phenotype and activated myofibroblasts while suppressing the profibrogenic phenotype, suggesting roles of PDCD4 in cellular senescence and fibrogenesis in the liver.

Catalpol inhibits hepatic stellate cell activation by reducing the formation and changing the contents of hepatocyte-derived extracellular vesicles.

Hepatic stellate cell (HSC) activation is the central event in hepatic fibrosis. The cross-talk between HSCs and hepatocytes, which is mediated by extracellular vesicles (EVs), affects HSC activation. This study aimed to investigate whether Catalpol (CTP) attenuated hepatic fibrosis via modulating EVs. Mice were injected intraperitoneally with CCl4 for 4weeks to induce hepatic fibrosis. They were gavaged with CTP daily. Mouse serum EVs were isolated and identified using nanoparticle tracking analysis and transmission electron microscopy. Mouse hepatocytes (AML12) and primary HSCs were used to investigate the cell-to-cell crosstalk. The autophagosome-autolysosome fusion was determined using the autophagic flux assay. Hepatic fibrosis was attenuated by CTP, with a decrease of the myofibroblast marker, alpha-smooth muscle actin. The CTP treatment lowered the serum EVs. The co-culture of HSCs and the EVs derived from the CTP-treated mice or hepatocytes reduced HSC proliferation and the expressions of ACTA2 and Col1a1. After the CCl4 treatment, the autophagosomes in AML12 cells were increased, while the autolysosomes were reduced. The decrease of autophagic cargo receptor SQSTM1 in the CTP group suggested that autophagic degradation was sustained. After inhibiting the endogenous Rac1-GTP of hepatocytes, the co-culture of EVs and HSCs reduced Rac1-GTP. The Rac1-GTP level in serum EVs from the CTP-treated mice was reduced in vivo. CTP inhibited autophagy in hepatocytes by reducing Rac1-GTP and thus affect the amount of Rac1-GTP in hepatocyte-derived EVs and the formation of EVs, which attenuated hepatic fibrosis via inhibiting HSC activation.

Phenotypic screening of 1,953 FDA-approved drugs reveals 26 hits with potential for repurposing for Peyronie's disease.

Drug repurposing has been shown to bring safe medications to new patient populations, as recently evidenced by the COVID-19 pandemic. We investigated whether we could use phenotypic screening to repurpose drugs for the treatment of Peyronie's disease (PD). PD is a fibrotic disease characterised by continued myofibroblast presence and activity leading to formation of a plaque in the penile tunica albuginea (TA) that can cause pain during erection, erectile dysfunction, and penile deformity. PD affects 3-9% of men with treatment options limited to surgery or injection of collagenase which can only be utilised at late stages after the plaque is formed. Currently there are no approved medications that can be offered to patients presenting with early disease before the formation of the plaque. Drug repurposing may therefore be the ideal strategy to identify medical treatments to address this unmet medical need in early PD. We used primary human fibroblasts from PD patients in a phenotypic screening assay that measures TGF-β1-induced myofibroblast transformation which is the main cellular phenotype that drives the pathology in early PD. A library of FDA-approved 1,953 drugs was screened in duplicate wells at a single concentration (10 μM) in presence of TGF-β1. The myofibroblast marker α-SMA was quantified after 72h incubation. A positive control of SB-505124 (TGF-β1 receptor antagonist) was included on each plate. Hits were defined as showing >80% inhibition, whilst retaining >80% cell viability. 26 hits (1.3%) were identified which were divided into the following main groups: anti-cancer drugs, anti-inflammation, neurology, endocrinology, and imaging agents. Five of the top-ten drugs that increase myofibroblast-transformation appear to act on VEGFR. This is the first phenotypic screening of FDA-approved drugs for PD and our results suggest that it is a viable method to predict drugs with potential for repurposing to treat early PD.

A Novel In Vitro Disease Model for Systemic Sclerosis Using Polyisocyanide Hydrogels

AbstractSystemic sclerosis (SSc) is a rare autoimmune disease with limited treatment options that is characterized by fibrosis in various organs. To screen the effectiveness of new therapies, there is an urgent need for reliable in vitro models. Key is that diseased cells' characteristics are maintained, which is challenging in currently used setups. In this study, an in vitro 3D culture system is described using the biocompatible polyisocyanide (PIC‐RGD) hydrogel and SSc patient‐derived fibroblasts from affected (lesional cells) and from healthy‐skin (healthy cells). In contrast to the standard collagen‐coated 2D cultures, the cells in the 3D PIC‐RGD gels maintain the native phenotype and functionality of the primary cells. The functionality of the model is studied in the presence of the fibrosis stimulator transforming growth factor β1 (TGFβ1) and the suppressor tumor necrosis factor (TNFα). In this study, it is observed that lesional cells have a stronger fibrotic character with increased contraction, proliferation, and expression of collagen, and myofibroblast markers α‐smooth muscle actin and fibroblast activation protein. The high tunability of the hydrogel, which can maintain the native functionality of fibroblasts in in vitro cultures, delivers a crucial step in developing these materials into an effective tool for personalized medicine approaches of SSc patients.

Oral Squamous Cell Carcinoma-Derived ANGPTL3 Induces Cancer Associated Fibroblastic Phenotypes in Surrounding Fibroblasts

Angiopoietin-like proteins (ANGPTLs) have emerged as both important regulator of lipid and glucose metabolism as well as insulin sensitivity. In particular, ANGPTL3 activity is one of the most important factors in cancer growth and invasion. Although ANGPTL3 have been studied in OSCC, but the role of ANGPTL3 between OSCC and CAFs has yet to be clearly defined. Thus, this study aimed to investigate the roles of ANGPTL3 in the differentiation of CAFs. For our study, we used hTERT-hNOFs to replace CAFs by coculturing them with oral squamous cell carcinoma (OSCC) cells. We did a microarray dataset analysis to investigate what factors secreted from OSCC cells can induce cancer associated fibroblastic phenotype in surrounding fibroblasts. The secreted factors were confirmed by RT-PCR, real-time PCR, and Western blot. ANGPTL3 has the most secreted factor derived from various oral cancer cells. To investigate the role of ANGPTL3 in CAFs, we treated rhANGPTL3 in hTERT-hNOFs. The fibroblasts showed an increase of tumor-promoting cytokines (IL-6 and IL-8) and myofibroblastic markers, such as α-SMA and FAP. In conclusion, our study reports the first evidence that ANGPTL3 plays a crucial role in tumor microenvironments by inducing CAF. Therefore, targeting ANGPTL3 may be promising treatment strategy for CAF-targeted therapy in CAF-rich tumors.

Losartan Inhibition of Myofibroblast Generation and Late Haze (Scarring Fibrosis) After PRK in Rabbits

To study the effect of topical losartan compared to vehicle on the generation of myofibroblasts and development of late haze scarring fibrosis after photorefractive keratectomy (PRK) in rabbits. Twelve rabbits had -9.00 diopter (D) PRK in one eye followed by 50 µL of topical 0.2 mg/mL losartan or 50 µL of vehicle six times per day for 1 month. Standardized slit-lamp photographs were obtained prior to death. Duplex immunohistochemistry was performed on cryofixed corneas for myofibroblast marker alpha-smooth muscle actin (α-SMA) and keratocyte marker keratocan or collagen type IV and transforming growth factor (TGF)-β1. ImageJ software (National Institutes of Health) was used for quantitation. Topical losartan compared to vehicle significantly decreased corneal opacity (P = .04) and anterior stromal myofibroblast generation (P = .01) at 1 month after PRK. Topical losartan compared to vehicle also decreased anterior stromal non-basement membrane collagen type IV at 1 month after PRK (P = .004). Topical angiotensin converting enzyme II receptor inhibitor losartan, a known inhibitor of TGF-β signaling, decreased late haze scarring fibrosis and myofibroblast generation after -9.00 D PRK in rabbits compared to vehicle. It also decreases TGF-β-modulated, corneal fibroblast-produced, non-basement membrane stromal collagen type IV-likely also through inhibition of TGF-β signaling. [J Refract Surg. 2022;38(12):820-829.].

Three‐dimensional study on morphological changes of arterioles in Cerebral Amyloid Angiopathy

AbstractBackgroundThe accumulation of β‐amyloid plaques in the brain is a hallmark of Alzheimer’s disease. Vascular involvement is also common in the form of cerebral amyloid angiopathy (CAA), a vasculopathy that is produced when the β‐amyloid forms toxic deposits on vessels wall. The accumulation of β‐amyloid makes blood vessels stiff and increases the thickness of the vessel wall, reducing the blood flow and energy supply for the tissue. This predisposes to hemorrhage and contribute to cognitive decline and stroke.MethodWe used the CLARITY method to analyze tissue samples from patients with CAA to characterize changes to vessel morphology associated with vascular degeneration. The blood vessels were stained with isolectin, β‐amyloid with thiazine red, and proteins with primary antibodies associated with the vascular structure. We conducted 3D microscopy using a light sheet microscope and performed surface volume reconstruction to assess the morphology of rupturing vessel. We also measured arteriolar stiffness of vessels damaged using atomic force microscopy (AFM). Finally, we assessed cerebral blood flow and autoregulation in vivo in a novel mouse model of CAA using laser speckle flowetry.ResultVessels with CAA demonstrate an organized ring‐shaped deposits β‐amyloid. At sites, these rings are shattered and the vessel diameter increase. Degenerating vessels also demonstrate depletion of vascular smooth muscle, circumferential luminal dilation, and thickening of the vessel wall. Lysyl oxidase levels and markers of fibrosis are increased in vessels with degenerating features. We found that the arteriolar wall was more than 400% stiffer in CAA than in arterioles without CAA in the mice model. Finally, in a novel mouse model of CAA we are terming the VASC‐FAD model, resting cerebral blood flow and vasoreactivity are both reduced.ConclusionCombining the CLARITY technique associated with surface volume rendering and AFM we have a better overview of microhemorrhages to understand the vascular fragility and morphological changes, and accumulation of myofibroblast markers caused by the β‐amyloid deposition and stiffness. These features combine to alter the physiology of cerebral blood flow. Defining mechanism of microvascular degeneration in AD and CAA may lead to novel treatment targets to restore the ECM and vascular network integrity.

The Human Myofibroblast Marker Xylosyltransferase-I: A New Indicator for Macrophage Polarization.

Chronic inflammation and excessive synthesis of extracellular matrix components, such as proteoglycans (PG), by fibroblast- or macrophage-derived myofibroblasts are the hallmarks of fibrotic diseases, including systemic sclerosis (SSc). Human xylosyltransferase-I (XT-I), which is encoded by the gene XYLT1, is the key enzyme that is involved in PG biosynthesis. Increased cellular XYLT1 expression and serum XT-I activity were measured in SSc. Nothing is known so far about the regulation of XT-I in immune cells, and their contribution to the increase in measurable serum XT-I activity. We utilized an in vitro model, with primary human CD14+CD16+ monocyte-derived macrophages (MΦ), in order to investigate the role of macrophage polarization on XT-I regulation. The MΦ generated were polarized towards two macrophage phenotypes that were associated with SSc, which were classified as classical pro-inflammatory (M1-like), and alternative pro-fibrotic (M2-like) MΦ. The fully characterized M1- and M2-like MΦ cultures showed differential XT-I gene and protein expressions. The fibrotic M2-like MΦ cultures exhibited higher XT-I secretion, as well as increased expression of myofibroblast marker α-smooth muscle actin, indicating the onset of macrophage-to-myofibroblast transition (MMT). Thus, we identified XT-I as a novel macrophage polarization marker for in vitro generated M1- and M2-like MΦ subtypes, and broadened the view of XT-I as a myofibroblast marker in the process of MMT.

Cathelicidin Treatment Silences Epithelial-Mesenchymal Transition Involved in Pulmonary Fibrosis in a Murine Model of Hypersensitivity Pneumonitis.

Pulmonary fibrosis is becoming an increasingly common pathology worldwide. Unfortunately, this disorder is characterized by a bad prognosis: no treatment is known, and the survival rate is dramatically low. One of the most frequent reasons for pulmonary fibrosis is hypersensitivity pneumonitis (HP). As the main mechanism of pulmonary fibrosis is a pathology of the repair of wounded pulmonary epithelium with a pivotal role in epithelial-mesenchymal transition (EMT), we assumed that EMT silencing could prevent disease development. Because of several biological features including wound healing promotion, an ideal candidate for use in the treatment of pulmonary fibrosis seems to be cathelicidin. The aim of the studies was to understand the influence of cathelicidin on the EMT process occurring during lung fibrosis development in the course of HP. Cathelicidin's impact on EMT was examined in a murine model of HP, wherein lung fibrosis was induced by chronic exposure to extract of Pantoea agglomerans (SE-PA) by real-time PCR and Western blotting. Studies revealed that mouse exposure to cathelicidin did not cause any side changes in the expression of investigated genes/proteins. Simultaneously, cathelicidin administered together or after SE-PA decreased the elevated level of myofibroblast markers (Acta2/α-smooth muscle actin, Cdh2/N-cadherin, Fn1/Fibronectin, Vim/vimentin) and increased the lowered level of epithelial markers (Cdh1/E-cadherin, Ocln/occludin). Cathelicidin provided with SE-PA or after cessation of SE-PA inhalations reduced the expression of EMT-associated factors (Ctnnd1/β-catenin, Nfkb1/NFκB, Snail1/Snail, Tgfb1/TGFβ1 Zeb1/ZEB1, Zeb2/ZEB2) elevated by P. agglomerans. Cathelicidin's beneficial impact on the expression of genes/proteins involved in EMT was observed during and after the HP development; however, cathelicidin was not able to completely neutralize the negative changes. Nevertheless, significant EMT silencing in response to cathelicidin suggested the possibility of its use in the prevention/treatment of pulmonary fibrosis.