TGF-beta1-mediated fibroblast-myofibroblast terminal differentiation-the role of Smad proteins

Frequent Premature Atrial Contractions Lead to Adverse Atrial Remodeling and Atrial Fibrillation in a Swine Model

BACKGROUND

Frequent premature atrial complexes (PACs) are associated with future incident atrial fibrillation (AF), but whether PACs contribute to development of AF through adverse atrial remodeling has not been studied. This study aimed to explore the effect of frequent PACs from different sites on atrial remodeling in a swine model.

METHODS

Forty swine underwent baseline electrophysiologic studies and echocardiography followed by pacemaker implantations and paced PACs (50% burden) at 250-ms coupling intervals for 16 weeks in 4 groups: (1) lateral left atrium (LA) PACs by the coronary sinus (Lat-PAC; n=10), (2) interatrial septal PACs (Sep-PAC; n=10), (3) regular LA pacing at 130 beats/min (Reg-130; n=10), and (4) controls without PACs (n=10). At the final study, repeat studies were performed, followed by tissue histology and molecular analyses focusing on fibrotic pathways.

RESULTS

Lat-PACs were associated with a longer P-wave duration (93.0±9.0 versus 74.2±8.2 and 58.8±7.6 ms; P<0.001) and greater echocardiographic mechanical dyssynchrony (57.5±11.6 versus 35.7±13.0 and 24.4±11.1 ms; P<0.001) compared with Sep-PACs and controls, respectively. After 16 weeks, Lat-PACs led to slower LA conduction velocity (1.1±0.2 versus 1.3±0.2 [Sep-PAC] versus 1.3±0.1 [Reg-130] versus 1.5±0.2 [controls] m/s; P<0.001) without significant change in atrial ERP. The Lat-PAC group had a significantly increased percentage of LA fibrosis and upregulated levels of extracellular matrix proteins (lysyl oxidase and collagen 1 and 8), as well as TGF-β1 (transforming growth factor-β1) signaling proteins (latent and monomer TGF-β1 and phosphorylation/total ratio of SMAD2/3; P<0.05). The Lat-PAC group had the longest inducible AF duration (terminal to baseline: 131 [interquartile range 30, 192] seconds versus 16 [6, 26] seconds [Sep-PAC] versus 22 [11, 64] seconds [Reg-130] versus -1 [-16, 7] seconds [controls]; P<0.001).

CONCLUSIONS

In this swine model, frequent PACs resulted in adverse atrial structural remodeling with a heightened propensity to AF. PACs originating from the lateral LA produced greater atrial remodeling and longer induced AF duration than the septal-origin PACs. These data provide evidence that frequent PACs can cause adverse atrial remodeling as well as AF, and that the location of ectopic PACs may be clinically meaningful.

Time course evaluation of collagen type IV in Pectoralis major muscles of broiler chickens selected for different growth-rates

Collagen type IV (COL4) is one of the major components of animals' and humans' basement membranes of several tissues, such as skeletal muscles and vascular endothelia. Alterations in COL4 assembly and secretion are associated to muscular disorders in humans and animals among which growth-related abnormalities such as white striping and wooden breast affecting Pectoralis major muscles (PMs) in modern fast-growing (FG) chickens. Considering the high prevalence of these myopathies in FG broilers and that a worsening is observed as the bird slaughter age is increased, the present study was intended to evaluate the distribution and the expression level of COL4 protein and its coding genes in PMs of FG broilers at different stages of muscle development (i.e., 7, 14, 21, 28, 35, and 42 d of age). Medium-growing (MG) chickens have been considered as the control group in consideration of the lower selection pressure on breast muscle growth rate and hypertrophy. Briefly, 5 PM/sampling time/genotype were selected for western blot, immunohistochemistry (IHC), and gene expression analyses. The normalized expression levels of COL4 coding genes showed an overexpression of COL4A2 in FG than MG at d 28, as well as a significant decrease in its expression over their rearing period. Overall, results obtained through the gene expression analysis suggested that selection for the hypertrophic growth of FG broilers may have led to an altered regulation of fibroblast proliferation and COL4 synthesis. Moreover, western blot and IHC analyses suggested an altered secretion and/or degradation of COL4 protein in FG broilers, as evidenced by the fluctuating trend of 2 bands observed in FG over time. In view of the above, the present research supports the evidence about a potential aberrant synthesis and/or degradation of COL4 and corroborates the hypothesis regarding a likely involvement of COL4 in the series of events underlying the growth-related abnormalities in modern FG broilers.

Attenuated Replication-Competent Herpes Simplex Virus Expressing an ECM-Modifying Transgene Hyaluronan Synthase 2 of Naked Mole Rat in Oncolytic Gene Therapy

Herpes simplex virus (HSV) has proven successful in treating human cancer. Since the approval of talimogene laherparepvec (T-VEC) in 2015, HSV has been thoroughly researched to discover novel mechanisms to combat cancer and treat other diseases. Another HSV-based drug, beremagene geperpavec (B-VEC), received approval in 2023 to treat the rare genetic disease dystrophic epidermolysis bullosa, and was also the first clinically approved HSV vector carrying an extracellular matrix (ECM)-modifying transgene. The ECM is a network of macromolecules surrounding cells, which provides support and regulates cell growth and differentiation, the disruption of which is common in cancer. The naked mole rat (NMR) has a thick ECM and a unique mutation in the hyaluronan synthase 2 (HAS2) gene, which has been linked to the high cancer resistance of the species. To study the effect of this mutation in human cancer, we have developed an attenuated, replication-competent HSV vector expressing the NMR-HAS2 gene. The viral replication, transgene expression and cytotoxic effect of the novel vector was studied in glioma cells. Our results show that an attenuated, replication-competent HSV vector expressing a foreign ECM-modifying transgene, namely HAS2, provides an effective tool to study and combat cancer in humans.

Role of transforming growth factor-β in airway remodelling in bronchiolitis obliterans

Airway remodelling is the main pathological mechanism of bronchiolitis obliterans (BO). Several studies have found that transforming growth factor-β (TGF-β) expression is increased in BO during airway remodelling, where it plays an important role in various biological processes by binding to its receptor complex to activate multiple signalling proteins and pathways. This review examines the role of TGF-β in airway remodelling in BO and its potential as a therapeutic target, highlighting the mechanisms of TGF-β activation and signalling, cellular targets of TGF-β actions, and research progress in TGF-β signalling and TGF-β-mediated processes.

TJ-17 (Goreisan) mitigates renal fibrosis in a mouse model of folic acid-induced chronic kidney disease

BACKGROUND AND PURPOSE

TJ-17 (Goreisan), a traditional Japanese Kampo medicine, has been generally used to treat edema, such as heart failure, due to its diuretic effect. In the present study, we investigate the effects of TJ-17 on chronic kidney disease (CKD).

METHODS

We the preventive action of TJ-17 against acute kidney injury (AKI) transition to CKD in vivo using a folic acid (FA)-induced mouse model. Mice were treated with food containing TJ-17 at 48 h after FA intraperitoneal injection (AKI phase).

RESULTS

Histological analysis, as well as renal function and renal injury markers, deteriorated in mice with FA-induced CKD and were ameliorated by TJ-17 treatment. Increased levels of inflammatory cytokines and macrophage infiltration were also alleviated in mice treated with TJ-17. Renal fibrosis, a crucial factor in CKD, was induced by FA administration and inhibited by TJ-17 treatment. Pretreatment with TJ-17 did not exert an inhibitory effect on FA-induced AKI. The increase in urinary volume in FA-induced CKD mice was ameliorated by TJ-17 treatment, with a concurrent correction of reduced aquaporins expression in the kidney.

CONCLUSION

TJ-17 may have a novel preventive effect against inflammation, oxidative stress, and fibrosis, contributing to innovation in the treatment of CKD.

Smad2/3 signaling involved in urotensin II-induced phenotypic differentiation, collagen synthesis and migration of rat aortic adventitial fibroblasts

Objective. To investigate whether Smad2/3 signaling is involved in urotensin II (UII) induced activation of aortic adventitial fibroblasts. Materials and Methods. Growth-arrested adventitial fibroblasts were stimulated with UII in the presence or absence of urotensin II receptor (UT) antagonist SB710411 or transfected with Smad2/3 small inhibitory RNA (siRNA). UII stimulated Smad2/3 phosphorylation, α-smooth muscle actin (α-SMA), and collagen I expression and migration of adventitial fibroblasts were evaluated by western blot analysis, real-time reverse transcription polymerase chain reaction, immunofluorescence, ELISA, and transwell migration assay, respectively. Results. In cultured adventitial fibroblasts, UII time- and dose-dependently stimulated Smad2/3 protein phosphorylation, with maximal effect at 10-8 mol/l (increased by 147.2%, P<0.001). UII stimulated Smad2/3 upregulation and nuclear translocation. SB710411 significantly inhibited these effects. In addition, UII potently induced α-SMA and procollagen 1 protein or mRNA expression (P<0.01), which were completely blocked by Smad2 (decreased by 75.1%, 54.2% in protein, and by 73.3% and 38.2% in mRNA, respectively, P<0.01) or Smad3 siRNA (decreased by 80.3% and 47.0% in protein, and by 72.3% and 47.7% in mRNA, respectively, P<0.01). Meanwhile, Smad2 or smad3 siRNA significantly inhibited the UII-induced collagen 1 secretion and cell migration. Conclusions. UII may stimulate adventitial-fibroblast phenotype conversion, migration, and collagen I synthesis via phosphorylated-Smad2/3 signal transduction pathways.

Emergent Peptides of the Antifibrotic Arsenal: Taking Aim at Myofibroblast Promoting Pathways

Myofibroblasts are the principal effector cells driving fibrosis, and their accumulation in tissues is a fundamental feature of fibrosis. Essential pathways have been identified as being central to promoting myofibroblast differentiation, revealing multiple targets for intervention. Compared with large proteins and antibodies, peptide-based therapies have transpired to serve as biocompatible and cost-effective solutions to exert biomimicry, agonistic, and antagonistic activities with a high degree of targeting specificity and selectivity. In this review, we summarize emergent antifibrotic peptides and their utilization for the targeted prevention of myofibroblasts. We then highlight recent studies on peptide inhibitors of upstream pathogenic processes that drive the formation of profibrotic cell phenotypes. We also briefly discuss peptides from non-mammalian origins that show promise as antifibrotic therapeutics. Finally, we discuss the future perspectives of peptide design and development in targeting myofibroblasts to mitigate fibrosis.

Chronic activation of human cardiac fibroblasts in vitro attenuates the reversibility of the myofibroblast phenotype

Activation of cardiac fibroblasts and differentiation to myofibroblasts underlies development of pathological cardiac fibrosis, leading to arrhythmias and heart failure. Myofibroblasts are characterised by increased α-smooth muscle actin (α-SMA) fibre expression, secretion of collagens and changes in proliferation. Transforming growth factor-beta (TGF-β) and increased mechanical stress can initiate myofibroblast activation. Reversibility of the myofibroblast phenotype has been observed in murine cells but has not been explored in human cardiac fibroblasts. In this study, chronically activated adult primary human ventricular cardiac fibroblasts and human induced pluripotent stem cell derived cFbs (hiPSC-cFbs) were used to investigate the potential for reversal of the myofibroblast phenotype using either subculture on soft substrates or TGF-β receptor inhibition. Culture on softer plates (25 or 2 kPa Young's modulus) did not alter proliferation or reduce expression of α-SMA and collagen 1. Similarly, culture of myofibroblasts in the presence of TGF-β inhibitor did not reverse myofibroblasts back to a quiescent phenotype. Chronically activated hiPSC-cFbs also showed attenuated response to TGF-β receptor inhibition and inability to reverse to quiescent fibroblast phenotype. Our data demonstrate substantial loss of TGF-β signalling plasticity as well as a loss of feedback from the surrounding mechanical environment in chronically activated human myofibroblasts.

Benzylisoquinoline alkaloids inhibit lung fibroblast activation mainly via inhibiting TGF-β1/Smads and ERK1/2 pathway proteins

Backgrounds

Liensinine (Lien), Neferine (Nef), Isoliensinine (Iso) and Tetrandrine (Tet), benzylisoquinoline alkaloids (BIAs), have been shown inhibitory effects on pulmonary fibrosis (PF) through anti-inflammatory, anti-oxidative activities, inhibition of cytokines and NF-κB. Effects of other similar BIAs, Dauricine (Dau), Papaverine (Pap) and lotusine (Lot), on PF remain unclear. Here, we explored the effects of five bisbenzylisoquinoline (Lien, Nef, Iso, Tet and Dau) and two monobenzylisoquinoline (Pap, Lot) alkaloids on normal and PF fibroblasts.

Methods

Primary normal and PF lung fibroblasts were cultured and treated with these alkaloids. Proliferation, activation, migration and apoptosis changes were detected by MTT, wound healing assay, flow cytometry. Protein level was analyzed by Western blot.

Results

All BIAs inhibited proliferation of normal and PF lung fibroblasts induced by TGF-β. α-SMA protein level in normal and PF lung fibroblasts decreased after Lien, Nef, Iso, Tet and Dau treatment. Pap and Lot had no influence on α-SMA expression. Dau showed the strongest inhibitory effects on proliferation and activation among alkaloids. The migration rates of normal and PF lung fibroblasts were inhibited by Lien, Nef, Iso, and Dau. Lien, Nef, Iso and Dau significantly promoted apoptosis, while Tet had no effect on apoptosis. Pap and Lot had no influence on activation, migration and apoptosis. Dau significantly inhibited Smad3/4 and p-ERK1/2 protein overexpression induced by TGF-β1.

Conclusions

Bisbenzylisoquinoline alkaloids had stronger effects on inhibiting lung fibroblasts than monobenzylisoquinoline alkaloids. Dau expressed the strongest inhibitory effects, which may be related to its inhibition of TGF-β1/Smad3/4 and p-ERK1/2 pathway proteins.

TGF-β Type I Receptor Signaling in Melanoma Liver Metastases Increases Metastatic Outgrowth

Despite advances in treatment for metastatic melanoma patients, patients with liver metastasis have an unfavorable prognosis. A better understanding of the development of liver metastasis is needed. The multifunctional cytokine Transforming Growth Factor β (TGF-β) plays various roles in melanoma tumors and metastasis, affecting both tumor cells and cells from the surrounding tumor microenvironment. To study the role of TGF-β in melanoma liver metastasis, we created a model to activate or repress the TGF-β receptor pathway in vitro and in vivo in an inducible manner. For this, we engineered B16F10 melanoma cells to have inducible ectopic expression of a constitutively active (ca) or kinase-inactive (ki) TGF-β receptor I, also termed activin receptor-like kinase (ALK5). In vitro, stimulation with TGF-β signaling and ectopic caALK5 expression reduced B16F10 cell proliferation and migration. Contrasting results were found in vivo; sustained caALK5 expression in B16F10 cells in vivo increased the metastatic outgrowth in liver. Blocking microenvironmental TGF-β did not affect metastatic liver outgrowth of both control and caALK5 expressing B16F10 cells. Upon characterizing the tumor microenvironment of control and caALk5 expressing B16F10 tumors, we observed reduced (cytotoxic) T cell presence and infiltration, as well as an increase in bone marrow-derived macrophages in caALK5 expressing B16F10 tumors. This suggests that caALK5 expression in B16F10 cells induces changes in the tumor microenvironment. A comparison of newly synthesized secreted proteins upon caALK5 expression by B16F10 cells revealed increased secretion of matrix remodeling proteins. Our results show that TGF-β receptor activation in B16F10 melanoma cells can increase metastatic outgrowth in liver in vivo, possibly through remodeling of the tumor microenvironment leading to altered infiltration of immune cells. These results provide insights in the role of TGF-β signaling in B16F10 liver metastasis and could have implications regarding the use of TGF-β inhibitors for the treatment of melanoma patients with liver metastasis.

Advanced Cell Culture Models Illuminate the Interplay between Mammary Tumor Cells and Activated Fibroblasts

The interaction between tumor cells and activated fibroblasts determines malignant features of desmoplastic carcinomas such as rapid growth, progression towards a metastatic phenotype, and resistance to chemotherapy. On one hand, tumor cells can activate normal fibroblasts and even reprogram them into CAFs through complex mechanisms that also involve soluble factors. Among them, transforming growth factor beta (TGF-β) and Platelet-Derived Growth Factor (PDGF) have an established role in the acquisition of pro-tumorigenic phenotypes by fibroblasts. On the other hand, activated fibroblasts release Interleukin-6 (IL-6), which increases tumor-cell invasiveness and chemoresistance. However, the interplay between breast cancer cells and fibroblasts, as well as the modes of action of TGF-β, PDGF, and IL-6, are difficult to investigate in vivo. Here, we validated the usage of advanced cell culture models as tools to study the interplay between mammary tumor cells and fibroblasts, taking mouse and human triple-negative tumor cells and fibroblasts as a case study. We employed two different settings, one permitting only paracrine signaling, the other both paracrine and cell-contact-based signaling. These co-culture systems allowed us to unmask how TGF-β, PDGF and IL-6 mediate the interplay between mammary tumor cells and fibroblasts. We found that the fibroblasts underwent activation induced by the TGF-β and the PDGF produced by the tumor cells, which increased their proliferation and IL-6 secretion. The IL-6 secreted by activated fibroblasts enhanced tumor-cell proliferation and chemoresistance. These results show that these breast cancer avatars possess an unexpected high level of complexity, which resembles that observed in vivo. As such, advanced co-cultures provide a pathologically relevant tractable system to study the role of the TME in breast cancer progression with a reductionist approach.

Oral Submucous Fibrosis: Etiological Mechanism, Malignant Transformation, Therapeutic Approaches and Targets

Oral submucosal fibrosis (OSF) is a chronic, progressive and potentially malignant oral disorder with a high regional incidence and malignant rate. With the development of the disease, the normal oral function and social life of patients are seriously affected. This review mainly introduces the various pathogenic factors and mechanisms of OSF, the mechanism of malignant transformation into oral squamous cell carcinoma (OSCC), and the existing treatment methods and new therapeutic targets and drugs. This paper summarizes the key molecules in the pathogenic and malignant mechanism of OSF, the miRNAs and lncRNAs with abnormal changes, and the natural compounds with therapeutic effects, which provides new molecular targets and further research directions for the prevention and treatment of OSF.

Homologous recombination deficiency in triple-negative breast cancer: Multi-scale transcriptomics reveals distinct tumor microenvironments and limitations in predicting immunotherapy response

BACKGROUND

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer and has the highest proportion of homologous recombination deficiency (HRD). HRD has been considered a biomarker of response to immune checkpoint inhibitors (ICIs), but the reality is more complicated. A comprehensive comparison of the tumor microenvironment (TME) in HRD and non-HRD TNBC samples may be helpful.

METHODS

Datasets from single-cell, spatial, and bulk RNA-sequencing were collected to explore the role of HRD in the development of TME at multiple scales. Based on the findings in the TME, machine learning algorithms were used to construct a response prediction model in eleven ICI therapy cohorts.

RESULTS

A more exhausted phenotype of T cells and a more tolerogenic phenotype of dendritic cells were found in the non-HRD group. HRD reprograms the predominant phenotype of cancer-associated fibroblasts (CAFs) from myofibroblastic CAFs to inflammatory-like CAFs. As interactions between myofibroblastic CAFs and other cells, DPP4-chemokines associated with reduced immune cell recruitment were unique in the non-HRD group. The prediction model based on DPP4-related genes had acceptable performance in predicting response, prognosis, and immune cell content. Higher HRD scores in bulk RNA-sequencing samples indicated more activated immune cell function, but not higher immune cell content, which may be affected by factors such as antigen-presenting capacity.

CONCLUSIONS

Based on multi-scale transcriptomics, our findings comprehensively reveal differences in the TME between HRD and non-HRD samples. Combining HRD with the prediction model or other methods for assessing immune cell content, may better predict response to ICIs in TNBC.

Biomechanical and Mechanobiological Drivers of the Transition From PostCapillary Pulmonary Hypertension to Combined Pre-/PostCapillary Pulmonary Hypertension

Combined pre-/postcapillary pulmonary hypertension (Cpc-PH), a complication of left heart failure, is associated with higher mortality rates than isolated postcapillary pulmonary hypertension alone. Currently, knowledge gaps persist on the mechanisms responsible for the progression of isolated postcapillary pulmonary hypertension (Ipc-PH) to Cpc-PH. Here, we review the biomechanical and mechanobiological impact of left heart failure on pulmonary circulation, including mechanotransduction of these pathological forces, which lead to altered biological signaling and detrimental remodeling, driving the progression to Cpc-PH. We focus on pathologically increased cyclic stretch and decreased wall shear stress; mechanotransduction by endothelial cells, smooth muscle cells, and pulmonary arterial fibroblasts; and signaling-stimulated remodeling of the pulmonary veins, capillaries, and arteries that propel the transition from Ipc-PH to Cpc-PH. Identifying biomechanical and mechanobiological mechanisms of Cpc-PH progression may highlight potential pharmacologic avenues to prevent right heart failure and subsequent mortality.

Unusual Suspects: Bone and Cartilage ECM Proteins as Carcinoma Facilitators

The extracellular matrix (ECM) is the complex three-dimensional network of fibrous proteins and proteoglycans that constitutes an essential part of every tissue to provide support for normal tissue homeostasis. Tissue specificity of the ECM in its topology and structure supports unique biochemical and mechanical properties of each organ. Cancers, like normal tissues, require the ECM to maintain multiple processes governing tumor development, progression and spread. A large body of experimental and clinical evidence has now accumulated to demonstrate essential roles of numerous ECM components in all cancer types. Latest findings also suggest that multiple tumor types express, and use to their advantage, atypical ECM components that are not found in the cancer tissue of origin. However, the understanding of cancer-specific expression patterns of these ECM proteins and their exact roles in selected tumor types is still sketchy. In this review, we summarize the latest data on the aberrant expression of bone and cartilage ECM proteins in epithelial cancers and their specific functions in the pathogenesis of carcinomas and discuss future directions in exploring the utility of this selective group of ECM components as future drug targets.

The sweet side of wound healing: galectins as promising therapeutic targets in hemostasis, inflammation, proliferation, and maturation/remodeling

INTRODUCTION

Understanding the molecular and cellular processes involved in skin wound healing may pave the way for the development of innovative approaches to transforming the identified natural effectors into therapeutic tools. Based on the extensive involvement of the ga(lactoside-binding)lectin family in (patho)physiological processes, it has been well established that galectins are involved in a wide range of cell-cell and cell-matrix interactions.

AREAS COVERED

In the present paper, we provide an overview of the biological role of galectins in repair and regeneration, focusing on four main phases (hemostasis, inflammation, proliferation, and maturation/remodeling) of skin repair using basic wound models (open excision vs. sutured incision).

EXPERT OPINION

The reported data make a strong case for directing further efforts to treat excisional and incisional wounds differently. Functions of galectins essentially result from their modular presentation. In fact, Gal-1 seems to play a role in the early phases of healing (anti-inflammatory) and wound contraction, Gal-3 accelerates re-epithelization and increases tensile strength (scar inductor). Galectins have also become subject of redesigning by engineering to optimize the activity. Clinically relevant, these new tools derived from the carbohydrate recognition domain platform may also prove helpful for other purposes, such as potent antibacterial agglutinins and opsonins.

Autoimmunity, cancer and COVID-19 abnormally activate wound healing pathways: critical role of inflammation

Recent evidence indicates that targeting IL-6 provides broad therapeutic approaches to several diseases. In patients with cancer, autoimmune diseases, severe respiratory infections [e.g. coronavirus disease 2019 (COVID-19)] and wound healing, IL-6 plays a critical role in modulating the systemic and local microenvironment. Elevated serum levels of IL-6 interfere with the systemic immune response and are associated with disease progression and prognosis. As already noted, monoclonal antibodies blocking either IL-6 or binding of IL-6 to receptors have been used/tested successfully in the treatment of rheumatoid arthritis, many cancer types, and COVID-19. Therefore, in the present review, we compare the impact of IL-6 and anti-IL-6 therapy to demonstrate common (pathological) features of the studied diseases such as formation of granulation tissue with the presence of myofibroblasts and deposition of new extracellular matrix. We also discuss abnormal activation of other wound-healing-related pathways that have been implicated in autoimmune disorders, cancer or COVID-19.

Identification of Key Genes and Molecular Pathways in Keratoconus: Integrating Text Mining and Bioinformatics Analysis

Purpose. To identify the potential key genes and molecular pathways associated with keratoconus and allergic disease. Methods. The pubmed2ensembl database was used to identify the text mining genes (TMGs) collectively involved in keratoconus and allergic disease. The GeneCodis program was used to perform the Gene Ontology (GO) biological process and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of TMGs. The protein-protein interaction (PPI) network of the TMGs was established by STRING; the significant gene modules and hub genes of PPI were further performed using the Cytoscape software. The DAVID database was used to perform the GO and KEGG analyses of the significant module. Results. In total, 98 TMGs collectively involved in keratoconus and allergic disease were identified. 19 enriched biological processes including 71 genes and 25 enriched KEGG pathways including 59 genes were obtained. A TMG PPI network was constructed, and 51 genes/nodes were identified with 110 edges; 3 most significant modules and 12 hub genes were chosen from the PPIs. GO enrichment analysis showed that the TMGs were primarily associated with collagen catabolic process, extracellular matrix organization and disassembly, cell adhesion and migration, collagen-containing extracellular matrix, extracellular matrix, and structure organization. KEGG pathway analysis showed that these DEGs were mainly involved in the IL-17 signaling pathway, inflammatory bowel disease, rheumatoid arthritis, allograft rejection, T cell receptor signaling pathway, cytokine-cytokine receptor interaction, and TNF signaling pathway. Conclusions. The results revealed that IL10, IL6, MMP9, MMP1, HGF, VEGFA, MMP3, MMP2, TGFB1, IL4, IL2, and IFNG were potential key genes involved in keratoconus. IL-17 signaling pathway was the potential pathways accounting for pathogenesis and development of keratoconus.

NHLRC2 expression is increased in idiopathic pulmonary fibrosis

BACKGROUND

Variants of NHL repeat-containing protein 2 (NHLRC2) have been associated with severe fibrotic interstitial lung disease in early childhood and NHLRC2 has been listed as a differentially expressed gene between rapidly and slowly progressing idiopathic pulmonary fibrosis (IPF) patients. However, its cell type-specific localization in human lung tissue is unknown. The aim of this study was to evaluate NHLRC2 mRNA and protein expression in different cell types of lung tissue samples and to investigate the effect of transforming growth factor (TGF)-β1 exposure on NHLRC2 expression in vitro.

METHODS

The NHLRC2 expression in lung tissue samples was studied by immunohistochemistry (50 IPF, 10 controls) and mRNA in situ hybridization (8 IPF, 3 controls). The immunohistochemical NHLRC2 expression was quantified with image analysis software and associated with the clinical and smoking data of the patients. NHLRC2 expression levels in primary stromal and small airway epithelial cell lines after exposure to TGF-β1 was measured by quantitative reverse transcription polymerase chain reaction and Western blot analysis.

RESULTS

NHLRC2 expression was detected especially in bronchiolar epithelial cells, type II pneumocytes and macrophages in normal lung. In the lungs of IPF patients, NHLRC2 was mainly expressed in hyperplastic alveolar epithelial cells lining fibroblast foci and honeycombs. NHLRC2 expression assessed by image analysis was higher in IPF compared to controls (p < 0.001). Ever-smokers had more prominent NHLRC2 staining than non-smokers (p = 0.037) among IPF patients. TGF-β1 exposure did not influence NHLRC2 levels in lung cell lines.

CONCLUSIONS

NHLRC2 expression was higher in IPF compared to controls being widely expressed in type II pneumocytes, macrophages, bronchiolar epithelium, and hyperplastic alveolar epithelium. Additionally, its expression was not regulated by the exposure to TGF-β1 in vitro. Further studies are needed to clarify the role of NHLRC2 in IPF.

Ogerin mediated inhibition of TGF-β(1) induced myofibroblast differentiation is potentiated by acidic pH

Transforming growth factor beta (TGF-β) induced myofibroblast differentiation is central to the pathological scarring observed in Idiopathic Pulmonary Fibrosis (IPF) and other fibrotic diseases. Our lab has recently identified expression of GPR68 (Ovarian Cancer Gene Receptor 1, OGR1), a pH sensing G-protein coupled receptor, as a negative regulator of TGF-β induced profibrotic effects in primary human lung fibroblasts (PHLFs). We therefore hypothesized that small molecule activators of GPR68 would inhibit myofibroblast differentiation. Ogerin is a positive allosteric modulator (PAM) of GPR68, inducing a leftward shift of the dose response curve to proton induced signaling. Using PHLFs derived from patients with both non-fibrotic and IPF diagnoses, we show that Ogerin inhibits, and partially reverses TGF-β induced myofibroblast differentiation in a dose dependent manner. This occurs at the transcriptional level without inhibition of canonical TGF-β induced SMAD signaling. Ogerin induces PKA dependent CREB phosphorylation, a marker of Gαs pathway activation. The ability of Ogerin to inhibit both basal and TGF-β induced collagen gene transcription, and induction of Gαs signaling is enhanced at an acidic pH (pH 6.8). Similar findings were also found using fibroblasts derived from dermal, intestinal, and orbital tissue. The biological role of GPR68 in different tissues, cell types, and disease states is an evolving and emerging field. This work adds to the understanding of Gαs coupled GPCRs in fibrotic lung disease, the ability to harness the pH sensing properties of GPR68, and conserved mechanisms of fibrosis across different organ systems.

Revealing the pathogenic and ageing-related mechanisms of the enigmatic idiopathic pulmonary fibrosis (and chronic obstructive pulmonary disease)

PURPOSE OF REVIEW

Growing evidence suggests that ageing-associated alterations occur in both idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD). Here, we review the most recent literature on dysregulated ageing pathways in IPF and COPD and discuss how they may contribute to disease pathogenesis.

RECENT FINDINGS

Recent studies have shown that alveolar epithelial type II (ATII) cells undergo premature senescence under stress and that senescent ATII cells promote lung fibrogenesis. Some studies have explored the role of mitochondrial dysfunction in IPF. They have provided evidence that dysfunctional mitochondria are important contributors to fibrogenesis through release of damaged DNA and excessive formation of reactive oxygen species, whereas restoration of mitochondrial homeostasis may attenuate lung fibrosis. Insufficient autophagy has been shown to promote epithelial-to-mesenchymal transition and aberrant epithelial-fibroblast crosstalk, suggesting that autophagy augmentation may represent a potential therapeutic strategy. A number of studies have also explored the role of cellular senescence, mitochondrial homeostasis and autophagy in COPD.

SUMMARY

Several ageing mechanisms are dysregulated in the lungs of patients with IPF and COPD, although how they contribute to disease development and progression remains elusive. Genetic or pharmacologic attenuation of senescence-related pathways and elimination of senescent cells may represent a promising therapeutic strategy.

Human primary chronic wound derived fibroblasts demonstrate differential pattern in expression of fibroblast specific markers, cell cycle arrest and reduced proliferation

INTRODUCTION

Although wound refers to simple cut in the skin, most wounds don't heal because of the various local and systemic factors that lead to its complexity and chronicity. Thus, prior understanding of the status of the wound is necessary and methods that can differentiate between the healing and non-healing wounds at a much earlier stage is crucial for a successful treatment.

METHODS

The current study aims at differentiating Acute Wound Fibroblasts (AWFs) and Chronic Wound Fibroblasts (CWFs) based on differential expression of fibroblast specific markers such as Vimentin and Alpha Smooth Muscle Actin (α-SMA) and compare its cell cycle and proliferation.

RESULTS

Immunostaining and western blotting analysis showed that, AWFs and CWFs differentially expressed vimentin and α-SMA, with AWFs and CWFs showing higher expression of vimentin and α-SMA respectively. AWFs showed higher distributions in G0/G1 (67.43% vs. 62.16%), S phase (22.61% vs. 8.51%) compared to CWFs. However, AWFs showed decreased distributions compared to CWFs in G2 + M phase (8.14% vs. 10.6%). Thus, it was observed that CWFs showed cell cycle arrest in the G1/G0 phase and inhibited DNA synthesis, which was further confirmed by reduced proliferation of CWFs. We suggest that, differential expression of the cell specific markers can be attributed to its pathophysiological status and chronicity of the wound and reduced proliferation rate of CWFs is due to lesser expression of vimentin, which is a key protein for in vitro cell proliferation.

CONCLUSIONS

Outcome of the study serve as an immunological tool to guide the chronicity of the wound, which helps to understand the wound towards design of personalized care. The findings also represent a promising opportunity to gain insight into how cell cycle arrest can impact on wound healing and clinical outcomes.

Research on the mechanism of berberine in the treatment of COVID-19 pneumonia pulmonary fibrosis using network pharmacology and molecular docking

Purpose Pulmonary fibrosis caused by COVID-19 pneumonia is a serious complication of COVID-19 infection, there is a lack of effective treatment methods clinically. This article explored the mechanism of action of berberine in the treatment of COVID-19 (Corona Virus Disease 2019, COVID-19) pneumonia pulmonary fibrosis with the help of the network pharmacology and molecular docking. Methods We predicted the role of berberine protein targets with the Pharmmapper database and the 3D structure of berberine in the Pubchem database. And GeneCards database was used in order to search disease target genes and screen common target genes. Then we used STRING web to construct PPI interaction network of common target protein. The common target genes were analyzed by GO and KEGG by DAVID database. The disease-core target gene-drug network was established and molecular docking was used for prediction. We also analyzed the binding free energy and simulates molecular dynamics of complexes. Results Berberine had 250 gene targets, COVID-19 pneumonia pulmonary fibrosis had 191 gene targets, the intersection of which was 23 in common gene targets. Molecular docking showed that berberine was associated with CCl2, IL-6, STAT3 and TNF-α. GO and KEGG analysis reveals that berberine mainly plays a vital role by the signaling pathways of influenza, inflammation and immune response. Conclusion Berberine acts on TNF-α, STAT3, IL-6, CCL2 and other targets to inhibit inflammation and the activation of fibrocytes to achieve the purpose of treating COVID-19 pneumonia pulmonary fibrosis.

Mechanical stretching can modify the papillary dermis pattern and papillary fibroblast characteristics during skin regeneration

Clinical application of mechanical stretching is a reconstructive method for skin repair. Although studies have reported dermal fibroblast heterogeneity, whether stretching affects individual fibroblast subpopulations equally remains unclear. Here, we show the changes in dermal structure and papillary fibroblast (Fp) in regenerated human skin. Exhausted skin regeneration caused dermal-epidermal junction (DEJ) flattening, papillary dermis thinning, and an increase in the type III collagen (COL3)/type I collagen (COL1) ratio with upregulated hallmarks of aging. Well-regenerated skin displayed a notable increase in the Fp population. Consistent changes were observed in the rat expansion model. Moreover, we found that TGFβ1 expression was especially increased in skin showing good regeneration. Activation of the TGFβ1/Smad2/3 pathway improved exhausted skin regeneration and resulted in increased collagen content and Fp proliferation, while pharmacological inhibition of TGFβ1 action impacted well-regenerated skin. Short-term mechanical stretching that promoted skin regeneration enhanced Fp proliferation, extracellular matrix (ECM) synthesis, and increased TGFβ1 expression, leading to good regeneration. Conversely, long-term stretching induced premature Fp senescence, leading to poor regeneration. This work shows the mechanism of mechanical stretching in well skin regeneration that enhances Fp proliferation and ECM synthesis via the TGFβ1/Smad2/3 pathway, and highlights a crucial role of Fps in stretching-induced skin regeneration.

Studying Activated Fibroblast Phenotypes and Fibrosis-Linked Mechanosensing Using 3D Biomimetic Models

Fibrosis and solid tumor progression are closely related, with both involving pathways associated with chronic wound dysregulation. Fibroblasts contribute to extracellular matrix (ECM) remodeling in these processes, a crucial step in scarring, organ failure, and tumor growth, but little is known about the biophysical evolution of remodeling regulation during the development and progression of matrix-related diseases including fibrosis and cancer. A 3D collagen-based scaffold model is employed here to mimic mechanical changes in normal (2 kPa, soft) versus advanced pathological (12 kPa, stiff) tissues. Activated fibroblasts grown on stiff scaffolds show lower migration and increased cell circularity compared to those on soft scaffolds. This is reflected in gene expression profiles, with cells cultured on stiff scaffolds showing upregulated DNA replication, DNA repair, and chromosome organization gene clusters, and a concomitant loss of ability to remodel and deposit ECM. Soft scaffolds can reproduce biophysically meaningful microenvironments to investigate early stage processes in wound healing and tumor niche formation, while stiff scaffolds can mimic advanced fibrotic and cancer stages. These results establish the need for tunable, affordable 3D scaffolds as platforms for aberrant stroma research and reveal the contribution of physiological and pathological microenvironment biomechanics to gene expression changes in the stromal compartment.

Colon stroma mediates an inflammation-driven fibroblastic response controlling matrix remodeling and healing

Chronic inflammation is often associated with the development of tissue fibrosis, but how mesenchymal cell responses dictate pathological fibrosis versus resolution and healing remains unclear. Defining stromal heterogeneity and identifying molecular circuits driving extracellular matrix deposition and remodeling stands to illuminate the relationship between inflammation, fibrosis, and healing. We performed single-cell RNA-sequencing of colon-derived stromal cells and identified distinct classes of fibroblasts with gene signatures that are differentially regulated by chronic inflammation, including IL-11-producing inflammatory fibroblasts. We further identify a transcriptional program associated with trans-differentiation of mucosa-associated fibroblasts and define a functional gene signature associated with matrix deposition and remodeling in the inflamed colon. Our analysis supports a critical role for the metalloprotease Adamdec1 at the interface between tissue remodeling and healing during colitis, demonstrating its requirement for colon epithelial integrity. These findings provide mechanistic insight into how inflammation perturbs stromal cell behaviors to drive fibroblastic responses controlling mucosal matrix remodeling and healing.

CaMKII Mediates TGFβ1-Induced Fibroblasts Activation and Its Cross Talk with Colon Cancer Cells

INTRODUCTION

Cancer-associated fibroblasts (CAFs), as the activated fibroblasts in tumor stroma, are important modifiers of tumor progression. TGFβ1 has been the mostly accepted factor to fuel normal fibroblasts transformation into CAFs. Ca²⁺/calmodulin-dependent protein kinase II (CaMKII) is thought to play an important role in fibroblasts activation induced by TGFβ1. The aim of this study is to investigate the potential role of CaMKII in TGFβ1-induced fibroblasts activation and CAF-like differentiation. Cross talk between CaMKII-dependent fibroblasts and colon cancer in colon cancer progression also was addressed RESULTS: Immunostaining demonstrated that in colon cancer stroma, CaMKII overexpressed in stromal CAFs. In vitro, TGFβ1 increased CAF markers expression in human colon fibroblasts CCD-18Co, but not in CaMKII depletion fibroblasts. CaMKII knockdown by CaMKII shRNA significantly inhibited TGFβ1-induced fibroblasts activation and CAF-like differentiation. Smad3, AKT, and MAPK were targeted in TGFβ1-CaMKII-mediated pathway. Human colon cancer cell line HCT-116 activated fibroblasts directly, whereas CaMKII depletion dragged CCD-18Co fibroblasts undergoing CAF-associated trans-differentiation. Furthermore, increased proliferation, migration, and invasion of colon cancer cells were stimulated when co-cultured with normal fibroblasts, but not with CaMKII depletion fibroblasts.

CONCLUSIONS

These findings provide evidence that CaMKII is a critical mediator in TGFβ1-induced fibroblasts activation and is involved in the cross talk with colon cancer cells. CaMKII is a potentially effective target for future treatment of colon cancer.

Fibroblast Differentiation and Matrix Remodeling Impaired under Simulated Microgravity in 3D Cell Culture Model

Exposure to microgravity affects astronauts' health in adverse ways. However, less is known about the extent to which fibroblast differentiation during the wound healing process is affected by the lack of gravity. One of the key steps of this process is the differentiation of fibroblasts into myofibroblasts, which contribute functionally through extracellular matrix production and remodeling. In this work, we utilized collagen-based three-dimensional (3D) matrices to mimic interstitial tissue and studied fibroblast differentiation under simulated microgravity (sµG). Our results demonstrated that alpha-smooth muscle actin (αSMA) expression and translocation of Smad2/3 into the cell nucleus were reduced upon exposure to sµG compared to the 1g control, which suggests the impairment of fibroblast differentiation under sµG. Moreover, matrix remodeling and production were decreased under sµG, which is in line with the impaired fibroblast differentiation. We further investigated changes on a transcriptomic level using RNA sequencing. The results demonstrated that sµG has less effect on fibroblast transcriptomes, while sµG triggers changes in the transcriptome of myofibroblasts. Several genes and biological pathways found through transcriptome analysis have previously been reported to impair fibroblast differentiation. Overall, our data indicated that fibroblast differentiation, as well as matrix production and remodeling, are impaired in 3D culture under sµG conditions.

A Review of the Molecular Mechanisms Underlying Cardiac Fibrosis and Atrial Fibrillation

The cellular and molecular mechanism involved in the pathogenesis of atrial fibrosis are highly complex. We have reviewed the literature that covers the effectors, signal transduction and physiopathogenesis concerning extracellular matrix (ECM) dysregulation and atrial fibrosis in atrial fibrillation (AF). At the molecular level: angiotensin II, transforming growth factor-β1, inflammation, and oxidative stress are particularly important for ECM dysregulation and atrial fibrotic remodelling in AF. We conclude that the Ang-II-MAPK and TGF-β1-Smad signalling pathways play a major, central role in regulating atrial fibrotic remodelling in AF. The above signalling pathways induce the expression of genes encoding profibrotic molecules (MMP, CTGF, TGF-β1). An important mechanism is also the generation of reactive oxygen species. This pathway induced by the interaction of Ang II with the AT₂R receptor and the activation of NADPH oxidase. Additionally, the interplay between cardiac MMPs and their endogenous tissue inhibitors of MMPs, is thought to be critical in atrial ECM metabolism and fibrosis. We also review recent evidence about the role of changes in the miRNAs expression in AF pathophysiology and their potential as therapeutic targets. Furthermore, keeping the balance between miRNA molecules exerting anti-/profibrotic effects is of key importance for the control of atrial fibrosis in AF.

Convenient Tuning of the Elasticity of Self-Assembled Nano-Sized Triterpenoids to Regulate Their Biological Activities

The impact of the mechanical properties of nanomedicines on their biological functions remains elusive due to the difficulty in tuning the elasticity of the vehicles without changing chemistry. Herein, we report the fabrication of elasticity-tunable self-assembled oleanolic acid (OA) nanoconstructs in an antiparallel zigzag manner and develop rigid nanoparticles (OA-NP) and flexible nanogels (OA-NG) as model systems to decipher the elasticity-biofunction relationship. OA-NG demonstrate less endocytosis and enhanced lysosome escape with deformation compared to OA-NP. Further in vitro and in vivo experiments show the active permeation of OA-NG into the interior of tumor with enhanced antitumor efficacy accompanied by decreased collagen production and eight- to tenfold immune cell infiltration. This study not only presents a facile and green strategy to develop flexible OA-NG for effective cancer treatment but also uncovers the crucial role of elasticity in regulating biological activity, which may provide reference for precise design of efficient nanomedicines.

P300/CBP-Associated Factor Activates Cardiac Fibroblasts by SMAD2 Acetylation

Various heart diseases cause cardiac remodeling, which in turn leads to ineffective contraction. Although it is an adaptive response to injury, cardiac fibrosis contributes to this remodeling, for which the reactivation of quiescent myofibroblasts is a key feature. In the present study, we investigated the role of the p300/CBP-associated factor (PCAF), a histone acetyltransferase, in the activation of cardiac fibroblasts. An intraperitoneal (i.p.) injection of a high dose (160 mg/kg) of isoproterenol (ISP) induced cardiac fibrosis and reduced the amount of the PCAF in cardiac fibroblasts in the mouse heart. However, the PCAF activity was significantly increased in cardiac fibroblasts, but not in cardiomyocytes, obtained from ISP-administered mice. An in vitro study using human cardiac fibroblast cells recapitulated the in vivo results; an treatment with transforming growth factor-β1 (TGF-β1) reduced the PCAF, whereas it activated the PCAF in the fibroblasts. PCAF siRNA attenuated the TGF-β1-induced increase in and translocation of fibrosis marker proteins. PCAF siRNA blocked TGF-β1-mediated gel contraction and cell migration. The PCAF directly interacted with and acetylated mothers against decapentaplegic homolog 2 (SMAD2). PCAF siRNA prevented TGF-β1-induced phosphorylation and the nuclear localization of SMAD2. These results suggest that the increase in PCAF activity during cardiac fibrosis may participate in SMAD2 acetylation and thereby in its activation.

Mechanical stretch sustains myofibroblast phenotype and function in microtissues through latent TGF-β1 activation

Developing methods to study tissue mechanics and myofibroblast activation may lead to new targets for therapeutic treatments that are urgently needed for fibrotic disease. Microtissue arrays are a promising approach to conduct relatively high-throughput research into fibrosis as they recapitulate key biomechanical aspects of the disease through a relevant 3D extracellular environment. In early work, our group developed a device called the MVAS-force to stretch microtissues while enabling simultaneous assessment of their dynamic mechanical behavior. Here, we investigated TGF-β1-induced fibroblast to myofibroblast differentiation in microtissue cultures using our MVAS-force device through assessing α-SMA expression, contractility and stiffness. In doing so, we linked cell-level phenotypic changes to functional changes that characterize the clinical manifestation of fibrotic disease. As expected, TGF-β1 treatment promoted a myofibroblastic phenotype and microtissues became stiffer and possessed increased contractility. These changes were partially reversible upon TGF-β1 withdrawal under a static condition, while, in contrast, long-term cyclic stretching maintained myofibroblast activation. This pro-fibrotic effect of mechanical stretching was absent when TGF-β1 receptors were inhibited. Furthermore, stretching promoted myofibroblast differentiation when microtissues were given latent TGF-β1. Altogether, these results suggest that external mechanical stretch may activate latent TGF-β1 and, accordingly, might be a powerful stimulus for continued myofibroblast activation to progress fibrosis. Further exploration of this pathway with our approach may yield new insights into myofibroblast activation and more effective therapeutic treatments for fibrosis.

The transformation of cancer-associated fibroblasts: Current perspectives on the role of TGF-β in CAF mediated tumor progression and therapeutic resistance

Over the last few years, the Transforming growth factor- β (TGF-β) has been significantly considered as an effective and ubiquitous mediator of cell growth. The cytokine, TGF-β is being increasingly recognized as the most potent inducer of cancer cell initiation, differentiation, migration as well as progression through both the SMAD-dependent and independent pathways. There is growing evidence that supports the role of secretory cytokine TGF-β as a crucial mediator of tumor-stroma crosstalk. Contextually, the CAFs are the prominent component of tumor stroma that helps in tumor progression and onset of chemoresistance. The interplay between the CAFs and the tumor cells through the paracrine signals is facilitated by cytokine TGF-β to induce the malignant progression. Here in this review, we have dissected the most recent advancements in understanding the mechanisms of TGF-β induced CAF activation, their multiple origins, and most importantly their role in conferring chemoresistance. Considering the pivotal role of TGF-β in tumor perogression and associated stemness, it is one the proven clinical targets We have also included the clinical trials going on, targeting the TGF-β and CAFs crosstalk with the tumor cells. Ultimately, we have underscored some of the outstanding issues that must be deciphered with utmost importance to unravel the successful strategies of anti-cancer therapies.

The Multifaceted Role of TGF-β in Gastrointestinal Tumors

Simple Summary

The transforming growth factor β signaling pathway elicits a broad range of physiological re-sponses, and its misregulation has been related to cancer. The secreted cytokine TGFβ exerts a tumor-suppressive effect that counteracts malignant transformation. However, once tumor has developed, TGFβ can support tumor progression regulating epithelial to mesenchymal transition, invasion and metastasis, stimulating fibrosis, angiogenesis and immune suppression. Here we review the dichotomous role of TGF-β in the progression of gastrointestinal tumors, as well as its intricate crosstalk with other signaling pathways. We also discuss about the therapeutic strate-gies that are currently explored in clinical trials to counteract TGF-β functions.

Abstract

Transforming growth factor-beta (TGF-β) is a secreted cytokine that signals via serine/threonine kinase receptors and SMAD effectors. Although TGF-β acts as a tumor suppressor during the early stages of tumorigenesis, it supports tumor progression in advanced stages. Indeed, TGF-β can modulate the tumor microenvironment by modifying the extracellular matrix and by sustaining a paracrine interaction between neighboring cells. Due to its critical role in cancer development and progression, a wide range of molecules targeting the TGF-β signaling pathway are currently under active clinical development in different diseases. Here, we focused on the role of TGF-β in modulating different pathological processes with a particular emphasis on gastrointestinal tumors.

Plumbagin attenuates traumatic tracheal stenosis in rats and inhibits lung fibroblast proliferation and differentiation via TGF-β1/Smad and Akt/mTOR pathways

Traumatic tracheal stenosis (TS) is a serious respiratory disease characterized by hyperplasia of airway granulation. Plumbagin (PLB) is a natural naphthoquinone component with anti-fibrotic properties. This research aimed to explore the roles of PLB in alleviating TS and the underlying mechanisms. For in vitro studies, lung fibroblasts (IMR-90 cells), with/without PLB treatment or TGF-β1 induction, were used. The viability and proliferation of IMR-90 cells were examined by CCK-8 and EdU incorporation assays. The differentiation of IMR-90 cells was assessed by detecting the mRNA and protein expression levels of collagen (COL)-1 and alpha-smooth muscle actin (α-SMA). Besides, immunofluorescence assay was conducted to evaluate the localization of α-SMA in TGF-β1-induced IMR-90 cells. Moreover, the combination of PLB with/without TβRI (SB-431,542), PI3K/Akt (Ly294002) or mTOR (rapamycin) inhibitor was pretreated on IMR-90 cells after TGF-β1 induction. For in vivo studies, a rat model of TS was established. The pathological features and severity of TS were determined by hematoxylin and eosin staining. The protein levels of TGF-β1/Smad and Akt/mTOR pathways were detected for both in vitro and in vivo models. PLB effectively inhibited the proliferation and differentiation of TGF-β1-induced IMR-90 cells, and suppressed TGF-β1/Smad and Akt/mTOR signaling pathways both in vivo and in vitro. Furthermore, PLB reduced the degree of TS in rats. Taken together, our results indicate that PLB regulates lung fibroblast activity and attenuates TS in rats by inhibiting TGF-β1/Smad and Akt/mTOR signaling pathways. In conclusion, this study implies that PLB may serve as a promising therapeutic compound for TS.

Myofibroblasts: Function, Formation, and Scope of Molecular Therapies for Skin Fibrosis

Myofibroblasts are contractile, α-smooth muscle actin-positive cells with multiple roles in pathophysiological processes. Myofibroblasts mediate wound contractions, but their persistent presence in tissues is central to driving fibrosis, making them attractive cell targets for the development of therapeutic treatments. However, due to shared cellular markers with several other phenotypes, the specific targeting of myofibroblasts has long presented a scientific and clinical challenge. In recent years, myofibroblasts have drawn much attention among scientific research communities from multiple disciplines and specialisations. As further research uncovers the characterisations of myofibroblast formation, function, and regulation, the realisation of novel interventional routes for myofibroblasts within pathologies has emerged. The research community is approaching the means to finally target these cells, to prevent fibrosis, accelerate scarless wound healing, and attenuate associated disease-processes in clinical settings. This comprehensive review article describes the myofibroblast cell phenotype, their origins, and their diverse physiological and pathological functionality. Special attention has been given to mechanisms and molecular pathways governing myofibroblast differentiation, and updates in molecular interventions.

TGF-β Signaling: From Tissue Fibrosis to Tumor Microenvironment

Transforming growth factor-β (TGF-β) signaling triggers diverse biological actions in inflammatory diseases. In tissue fibrosis, it acts as a key pathogenic regulator for promoting immunoregulation via controlling the activation, proliferation, and apoptosis of immunocytes. In cancer, it plays a critical role in tumor microenvironment (TME) for accelerating invasion, metastasis, angiogenesis, and immunosuppression. Increasing evidence suggest a pleiotropic nature of TGF-β signaling as a critical pathway for generating fibrotic TME, which contains numerous cancer-associated fibroblasts (CAFs), extracellular matrix proteins, and remodeling enzymes. Its pathogenic roles and working mechanisms in tumorigenesis are still largely unclear. Importantly, recent studies successfully demonstrated the clinical implications of fibrotic TME in cancer. This review systematically summarized the latest updates and discoveries of TGF-β signaling in the fibrotic TME.

Novel factors that activate and deactivate cardiac fibroblasts: A new perspective for treatment of cardiac fibrosis

Heart disease with attendant cardiac fibrosis kills more patients in developed countries than any other disease, including cancer. We highlight the recent literature on factors that activate and also deactivate cardiac fibroblasts. Activation of cardiac fibroblasts results in myofibroblasts phenotype which incorporates aSMA to stress fibres, express ED-A fibronectin, elevated PDGFRα and are hypersecretory ECM components. These cells facilitate both acute wound healing (infarct site) and chronic cardiac fibrosis. Quiescent fibroblasts are associated with normal myocardial tissue and provide relatively slow turnover of the ECM. Deactivation of activated myofibroblasts is a much less studied phenomenon. In this context, SKI is a known negative regulator of TGFb₁ /Smad signalling, and thus may share functional similarity to PPARγ activation. The discovery of SKI's potent anti-fibrotic role, and its ability to deactivate and/or myofibroblasts is featured and contrasted with PPARγ. While myofibroblasts are typically recruited from pools of potential precursor cells in a variety of organs, the importance of activation of resident cardiac fibroblasts has been recently emphasised. Myofibroblasts deposit ECM components at an elevated rate and contribute to both systolic and diastolic dysfunction with attendant cardiac fibrosis. A major knowledge gap exists as to specific proteins that may signal for fibroblast deactivation. As SKI may be a functionally pluripotent protein, we suggest that it serves as a scaffold to proteins other than R-Smads and associated Smad signal proteins, and thus its anti-fibrotic effects may extend beyond binding R-Smads. While cardiac fibrosis is causal to heart failure, the treatment of cardiac fibrosis is hampered by the lack of availability of effective pharmacological anti-fibrotic agents. The current review will provide an overview of work highlighting novel factors which cause fibroblast activation and deactivation to underscore putative therapeutic avenues for improving disease outcomes in cardiac patients with fibrosed hearts.

Extended-release of therapeutic microRNA via a host-guest supramolecular hydrogel to locally alleviate renal interstitial fibrosis

Activated fibroblasts are critical contributors to renal interstitial fibrosis thus becoming the cellular target for fibrosis treatment. Previously, microRNA 29 b (miR-29 b) is shown to be down-regulated in various animal models of renal fibrosis. Herein, we describe a facile strategy to achieve localized and sustained delivery of therapeutic microRNA to the kidney via a host-guest supramolecular hydrogel. Specifically, cationic bovine serum albumin is used to complex with miR-29 b to afford nanocomplexes (cBSA/miR-29 b), which is proven to specifically inhibit fibroblast activation in a dose-dependent manner in vitro. Following unilateral ureteral obstruction in mice, a single injection of the hydrogel loaded with cBSA/miR-29 b in vivo, significantly down-regulated proteins and genes related to fibrosis for up to 21 days without affecting the normal liver or kidney functions. Overall, the localized delivery of cBSA/miR-29 b via a host-guest supramolecular hydrogel represents a safe and effective intervention strategy to delay and reverse the progression of interstitial renal fibrosis.

TGF‑β1: Gentlemanly orchestrator in idiopathic pulmonary fibrosis (Review)

Idiopathic pulmonary fibrosis (IPF) is a worldwide disease characterized by the chronic and irreversible decline of lung function. Currently, there is no drug to successfully treat the disease except for lung transplantation. Numerous studies have been devoted to the study of the fibrotic process of IPF and findings showed that transforming growth factor-β1 (TGF-β1) plays a central role in the development of IPF. TGF-β1 promotes the fibrotic process of IPF through various signaling pathways, including the Smad, MAPK, and ERK signaling pathways. There are intersections between these signaling pathways, which provide new targets for researchers to study new drugs. In addition, TGF-β1 can affect the fibrosis process of IPF by affecting oxidative stress, epigenetics and other aspects. Most of the processes involved in TGF-β1 promote IPF, but TGF-β1 can also inhibit it. This review discusses the role of TGF-β1 in IPF.

Activation of transmembrane receptor tyrosine kinase DDR1-STAT3 cascade by extracellular matrix remodeling promotes liver metastatic colonization in uveal melanoma

Colonization is believed a rate-limiting step of metastasis cascade. However, its underlying mechanism is not well understood. Uveal melanoma (UM), which is featured with single organ liver metastasis, may provide a simplified model for realizing the complicated colonization process. Because DDR1 was identified to be overexpressed in UM cell lines and specimens, and abundant pathological deposition of extracellular matrix collagen, a type of DDR1 ligand, was noted in the microenvironment of liver in metastatic patients with UM, we postulated the hypothesis that DDR1 and its ligand might ignite the interaction between UM cells and their surrounding niche of liver thereby conferring strengthened survival, proliferation, stemness and eventually promoting metastatic colonization in liver. We tested this hypothesis and found that DDR1 promoted these malignant cellular phenotypes and facilitated metastatic colonization of UM in liver. Mechanistically, UM cells secreted TGF-β1 which induced quiescent hepatic stellate cells (qHSCs) into activated HSCs (aHSCs) which secreted collagen type I. Such a remodeling of extracellular matrix, in turn, activated DDR1, strengthening survival through upregulating STAT3-dependent Mcl-1 expression, enhancing stemness via upregulating STAT3-dependent SOX2, and promoting clonogenicity in cancer cells. Targeting DDR1 by using 7rh, a specific inhibitor, repressed proliferation and survival in vitro and in vivo outgrowth. More importantly, targeting cancer cells by pharmacological inactivation of DDR1 or targeting microenvironmental TGF-β1-collagen I loop exhibited a prominent anti-metastasis effect in mice. In conclusion, targeting DDR1 signaling and TGF-β signaling may be a novel approach to diminish hepatic metastasis in UM.

Sulfatase 2-Induced Cancer-Associated Fibroblasts Promote Hepatocellular Carcinoma Progression via Inhibition of Apoptosis and Induction of Epithelial-to-Mesenchymal Transition

Background

Sulfatase 2 (SULF2) removes the 6-O-sulfate groups from heparan sulfate proteoglycans (HSPG) and consequently alters the binding sites for various signaling molecules. Here, we elucidated the role of SULF2 in the differentiation of hepatic stellate cells (HSCs) into carcinoma-associated fibroblasts (CAFs) in the hepatocellular carcinoma (HCC) microenvironment and the mechanism underlying CAF-mediated HCC growth.

Methods

The clinical relevance of SULF2 and CAFs was examined using in silico and immunohistochemical (IHC) analyses. Functional studies were performed to evaluate the role of SULF2 in the differentiation of HSCs into CAFs and elucidate the mechanism underlying CAF-mediated HCC growth. Mechanistic studies were performed using the chromatin immunoprecipitation, luciferase reporter, and RNA immunoprecipitation assays. The in vitro findings were verified using the nude HCC xenograft mouse model.

Results

The Cancer Genome Atlas (TCGA) database and IHC analyses revealed that the expression of CAF markers, which was positively correlated with that of SULF2 in the HCC tissues, predicted unfavorable postsurgical outcomes. Co-culturing HSCs with HCC cells expressing SULF2 promoted CAF differentiation. Additionally, CAFs repressed HCC cell apoptosis by activating the SDF-1/CXCR4/PI3K/AKT signaling pathway. Meanwhile, SULF2-induced CAFs promoted epithelial-to-mesenchymal transition (EMT) of HCC cells by modulating the SDF-1/CXCR4/OIP5-AS1/miR-153-3p/SNAI1 axis. Studies using HCC xenograft mouse models demonstrated that OIP5-AS1 induced EMT by upregulating SNAI1 and promoted HCC growth in vivo.

Conclusion

These data indicated that SULF2 secreted by the HCC cells induced the differentiation of HSCs into CAFs through the TGFβ1/SMAD3 signaling pathway. SULF2-induced CAFs attenuated HCC apoptosis by activating the SDF-1/CXCR4/PI3K/AKT signaling pathway and induced EMT through the SDF-1/CXCR4/OIP5-AS1/miR-153-3p/SNAI1 axis. This study revealed a novel mechanism involved in the crosstalk between HCC cells and CAFs in the tumor microenvironment, which can aid in the development of novel and efficient therapeutic strategies for primary liver cancer.

WWTR1(TAZ)-CAMTA1 gene fusion is sufficient to dysregulate YAP/TAZ signaling and drive epithelioid hemangioendothelioma tumorigenesis

Epithelioid hemangioendothelioma (EHE) is a genetically homogenous vascular sarcoma that is a paradigm for TAZ dysregulation in cancer. EHE harbors a WWTR1(TAZ)-CAMTA1 gene fusion in >90% of cases, 45% of which have no other genetic alterations. In this study, we used a first of its kind approach to target the Wwtr1-Camta1 gene fusion to the Wwtr1 locus, to develop a conditional EHE mouse model whereby Wwtr1-Camta1 is controlled by the endogenous transcriptional regulators upon Cre activation. These mice develop EHE tumors that are indistinguishable from human EHE clinically, histologically, immunohistochemically, and genetically. Overall, these results demonstrate unequivocally that TAZ-CAMTA1 is sufficient to drive EHE formation with exquisite specificity, as no other tumor types were observed. Furthermore, we fully credential this unique EHE mouse model as a valid preclinical model for understanding the role of TAZ dysregulation in cancer formation and for testing therapies directed at TAZ-CAMTA1, TAZ, and YAP/TAZ signaling.

Targeting RGD-binding integrins as an integrative therapy for diabetic retinopathy and neovascular age-related macular degeneration

Integrins are a class of transmembrane receptors that are involved in a wide range of biological functions. Dysregulation of integrins has been implicated in many pathological processes and consequently, they are attractive therapeutic targets. In the ophthalmology arena, there is extensive evidence suggesting that integrins play an important role in diabetic retinopathy (DR), age-related macular degeneration (AMD), glaucoma, dry eye disease and retinal vein occlusion. For example, there is extensive evidence that arginyl-glycyl-aspartic acid (Arg-Gly-Asp; RGD)-binding integrins are involved in key disease hallmarks of DR and neovascular AMD (nvAMD), specifically inflammation, vascular leakage, angiogenesis and fibrosis. Based on such evidence, drugs that engage integrin-linked pathways have received attention for their potential to block all these vision-threatening pathways. This review focuses on the pathophysiological role that RGD-binding integrins can have in complex multifactorial retinal disorders like DR, diabetic macular edema (DME) and nvAMD, which are leading causes of blindness in developed countries. Special emphasis will be given on how RGD-binding integrins can modulate the intricate molecular pathways and regulate the underlying pathological mechanisms. For instance, the interplay between integrins and key molecular players such as growth factors, cytokines and enzymes will be summarized. In addition, recent clinical advances linked to targeting RGD-binding integrins in the context of DME and nvAMD will be discussed alongside future potential for limiting progression of these diseases.

A multi-ethnic genome-wide association study implicates collagen matrix integrity and cell differentiation pathways in keratoconus

Keratoconus is characterised by reduced rigidity of the cornea with distortion and focal thinning that causes blurred vision, however, the pathogenetic mechanisms are unknown. It can lead to severe visual morbidity in children and young adults and is a common indication for corneal transplantation worldwide. Here we report the first large scale genome-wide association study of keratoconus including 4,669 cases and 116,547 controls. We have identified significant association with 36 genomic loci that, for the first time, implicate both dysregulation of corneal collagen matrix integrity and cell differentiation pathways as primary disease-causing mechanisms. The results also suggest pleiotropy, with some disease mechanisms shared with other corneal diseases, such as Fuchs endothelial corneal dystrophy. The common variants associated with keratoconus explain 12.5% of the genetic variance, which shows potential for the future development of a diagnostic test to detect susceptibility to disease.

Organ Fibrosis and Autoimmunity: The Role of Inflammation in TGFβ-Dependent EMT

Recent advances in our understanding of the molecular pathways that control the link of inflammation with organ fibrosis and autoimmune diseases point to the epithelial to mesenchymal transition (EMT) as the common association in the progression of these diseases characterized by an intense inflammatory response. EMT, a process in which epithelial cells are gradually transformed to mesenchymal cells, is a major contributor to the pathogenesis of fibrosis. Importantly, the chronic inflammatory microenvironment has emerged as a decisive factor in the induction of pathological EMT. Transforming growth factor-β (TGF-β), a multifunctional cytokine, plays a crucial role in the induction of fibrosis, often associated with chronic phases of inflammatory diseases, contributing to marked fibrotic changes that severely impair normal tissue architecture and function. The understanding of molecular mechanisms underlying EMT-dependent fibrosis has both a basic and a translational relevance, since it may be useful to design therapies aimed at counteracting organ deterioration and failure. To this end, we reviewed the recent literature to better elucidate the molecular response to inflammatory/fibrogenic signals in autoimmune diseases in order to further the specific regulation of EMT-dependent fibrosis in more targeted therapies.

MKL1 deficiency results in a severe neutrophil motility defect due to impaired actin polymerization

Megakaryoblastic leukemia 1 (MKL1) promotes the regulation of essential cell processes, including actin cytoskeletal dynamics, by coactivating serum response factor. Recently, the first human with MKL1 deficiency, leading to a novel primary immunodeficiency, was identified. We report a second family with 2 siblings with a homozygous frameshift mutation in MKL1. The index case died as an infant from progressive and severe pneumonia caused by Pseudomonas aeruginosa and poor wound healing. The younger sibling was preemptively transplanted shortly after birth. The immunodeficiency was marked by a pronounced actin polymerization defect and a strongly reduced motility and chemotactic response by MKL1-deficient neutrophils. In addition to the lack of MKL1, subsequent proteomic and transcriptomic analyses of patient neutrophils revealed actin and several actin-related proteins to be downregulated, confirming a role for MKL1 as a transcriptional coregulator. Degranulation was enhanced upon suboptimal neutrophil activation, whereas production of reactive oxygen species was normal. Neutrophil adhesion was intact but without proper spreading. The latter could explain the observed failure in firm adherence and transendothelial migration under flow conditions. No apparent defect in phagocytosis or bacterial killing was found. Also, monocyte-derived macrophages showed intact phagocytosis, and lymphocyte counts and proliferative capacity were normal. Nonhematopoietic primary fibroblasts demonstrated defective differentiation into myofibroblasts but normal migration and F-actin content, most likely as a result of compensatory mechanisms of MKL2, which is not expressed in neutrophils. Our findings extend current insight into the severe immune dysfunction in MKL1 deficiency, with cytoskeletal dysfunction and defective extravasation of neutrophils as the most prominent features.