Smad7 effects on TGF-β and ErbB2 restrain myofibroblast activation and protect from postinfarction heart failure

Cardiac tissue-resident vesicles differentially modulate anti-fibrotic phenotype by age and sex through synergistic miRNA effects

Aging is a risk factor for cardiovascular disease, the leading cause of death worldwide. Cardiac fibrosis is a harmful result of repeated myocardial infarction that increases risk of morbidity and future injury. Interestingly, both rates and outcomes of cardiac fibrosis differ between young and aged individuals, as well as men and women. Here, for the first time, we identify and isolate matrix-bound extracellular vesicles from the left ventricles (LVs) of young or aged males and females in both human and murine models. These LV vesicles (LVVs) show differences in morphology and content between these four cohorts in both humans and mice. LVV effects on fibrosis were also investigated in vitro, and aged male LVVs were pro-fibrotic while other LVVs were anti-fibrotic. From these LVVs, we could identify therapeutic miRNAs to promote anti-fibrotic effects. Four miRNAs were identified and together, but not individually, demonstrated significant cardioprotective effects when transfected. This suggests that miRNA synergy can regulate cell response, not just individual miRNAs, and also indicates that biological agent-associated therapeutic effects may be recapitulated using non-immunologically active agents. Furthermore, that chronic changes in LVV miRNA content may be a major factor in sex- and age-dependent differences in clinical outcomes of cardiac fibrosis.

Known pathogenic gene variants and new candidates detected in sudden unexpected infant death using whole genome sequencing

The purpose of this study is to gain insights into potential genetic factors contributing to the infant's vulnerability to Sudden Unexpected Infant Death (SUID). Whole Genome Sequencing (WGS) was performed on 144 infants that succumbed to SUID, and 573 healthy adults. Variants were filtered by gnomAD allele frequencies and predictions of functional consequences. Variants of interest were identified in 88 genes, in 64.6% of our cohort. Seventy-three of these have been previously associated with SIDS/SUID/SUDP. Forty-three can be characterized as cardiac genes and are related to cardiomyopathies, arrhythmias, and other conditions. Variants in 22 genes were associated with neurologic functions. Variants were also found in 13 genes reported to be pathogenic for various systemic disorders and in two genes associated with immunological function. Variants in eight genes are implicated in the response to hypoxia and the regulation of reactive oxygen species (ROS) and have not been previously described in SIDS/SUID/SUDP. Seventy-two infants met the triple risk hypothesis criteria. Our study confirms and further expands the list of genetic variants associated with SUID. The abundance of genes associated with heart disease and the discovery of variants associated with the redox metabolism have important mechanistic implications for the pathophysiology of SUID.

Fibroblast-specific TGF-β signaling mediates cardiac dysfunction, fibrosis, and hypertrophy in obese diabetic mice

AIMS

Transforming growth factor (TGF)-β is up-regulated in the diabetic myocardium and may mediate fibroblast activation. We aimed at examining the role of TGF-β-induced fibroblast activation in the pathogenesis of diabetic cardiomyopathy.

METHODS AND RESULTS

We generated lean and obese db/db mice with fibroblast-specific loss of TbR2, the Type 2 receptor-mediating signaling through all three TGF-β isoforms, and mice with fibroblast-specific Smad3 disruption. Systolic and diastolic function, myocardial fibrosis, and hypertrophy were assessed. Transcriptomic studies and in vitro experiments were used to dissect mechanisms of fibroblast activation. Fibroblast-specific TbR2 loss attenuated systolic and diastolic dysfunction in db/db mice. The protective effects of fibroblast TbR2 loss in db/db mice were associated with attenuated fibrosis and reduced cardiomyocyte hypertrophy, suggesting that in addition to their role in fibrous tissue deposition, TGF-β-stimulated fibroblasts may also exert paracrine actions on cardiomyocytes. Fibroblast-specific Smad3 loss phenocopied the protective effects of fibroblast TbR2 loss in db/db mice. Db/db fibroblasts had increased expression of genes associated with oxidative response (such as Fmo2, encoding flavin-containing monooxygenase 2), matricellular genes (such as Thbs4 and Fbln2), and Lox (encoding lysyl oxidase). Ingenuity pathway analysis (IPA) predicted that neurohumoral mediators, cytokines, and growth factors (such as AGT, TGFB1, and TNF) may serve as important upstream regulators of the transcriptomic profile of diabetic mouse fibroblasts. IPA of scRNA-seq data identified TGFB1, p53, MYC, PDGF-BB, EGFR, and WNT3A/CTNNB1 as important upstream regulators underlying fibroblast activation in db/db hearts. Comparison of the transcriptome of fibroblasts from db/db mice with fibroblast-specific Smad3 loss and db/db Smad3 fl/fl controls identified Thbs4 [encoding thrombospondin-4 (TSP-4), a marker of activated fibroblasts] as a candidate diabetes-induced fibrogenic mediator. However, in vitro experiments showed no significant activating effects of matricellular or intracellular TSP-4 on cardiac fibroblasts.

CONCLUSION

Fibroblast-specific TGF-β/Smad3 signaling mediates ventricular fibrosis, hypertrophy, and dysfunction in Type 2 diabetes.

LIM kinase 2 activates cardiac fibroblasts and exacerbates postinfarction left ventricular remodeling via crosstalk between the canonical and non-canonical Wnt pathways

Ischemic heart failure rates rise despite decreased acute myocardial infarction (MI) mortality. Excessive myofibroblast activation post-MI leads to adverse remodeling. LIM kinases (LIMK1 and LIMK2) regulate cytoskeleton homeostasis and are pro-fibrotic markers in atrial fibrillation. However, their roles and mechanisms in postinfarction fibrosis and ventricular remodeling remain unclear. This study found that the expression of LIMKs elevated in the border zone (BZ) in mice MI models. LIMK1/2 double knockout (DKO) restrained pathological remodeling and reduced mortality by suppressing myofibroblast activation. By using adeno-associated virus (AAV) with a periostin promoter to overexpress LIMK1 or LIMK2, this study found that myofibroblast-specific LIMK2 overexpression diminished these effects in DKO mice, while LIMK1 did not. LIMK2 kinase activity was critical for myofibroblast proliferation by using AAV overexpressing mutant LIMK2 lack of kinase activity. According to phosphoproteome analysis, functional rescue experiments, co-immunoprecipitation, and protein-protein docking, LIMK2 led to the phosphorylation of β-catenin at Ser 552. LIMK2 nuclear translocation also played a role in myofibroblast proliferation after MI with the help of AAV overexpressing mutant LIMK2 without nuclear location signal. Chromatin immunoprecipitation sequencing identified that LIMK2 bound to Lrp6 promoter region in TGF-β treated cardiac fibroblasts, positively regulating Wnt signaling via Wnt receptor internalization. This study demonstrated that LIMK2 promoted myofibroblast proliferation and adverse cardiac remodeling after MI, by enhancing phospho-β-catenin (Ser552) and Lrp6 signaling. This suggested that LIMK2 could be a target for the treatment of postinfarction injury.

Overview of pyroptosis mechanism and in-depth analysis of cardiomyocyte pyroptosis mediated by NF-κB pathway in heart failure

The pyroptosis of cardiomyocytes has become an essential topic in heart failure research. The abnormal accumulation of these biological factors, including angiotensin II, advanced glycation end products, and various growth factors (such as connective tissue growth factor, vascular endothelial growth factor, transforming growth factor beta, among others), activates the nuclear factor-κB (NF-κB) signaling pathway in cardiovascular diseases, ultimately leading to pyroptosis of cardiomyocytes. Therefore, exploring the underlying molecular biological mechanisms is essential for developing novel drugs and therapeutic strategies. However, our current understanding of the precise regulatory mechanism of this complex signaling pathway in cardiomyocyte pyroptosis is still limited. Given this, this study reviews the milestone discoveries in the field of pyroptosis research since 1986, analyzes in detail the similarities, differences, and interactions between pyroptosis and other cell death modes (such as apoptosis, necroptosis, autophagy, and ferroptosis), and explores the deep connection between pyroptosis and heart failure. At the same time, it depicts in detail the complete pathway of the activation, transmission, and eventual cardiomyocyte pyroptosis of the NF-κB signaling pathway in the process of heart failure. In addition, the study also systematically summarizes various therapeutic approaches that can inhibit NF-κB to reduce cardiomyocyte pyroptosis, including drugs, natural compounds, small molecule inhibitors, gene editing, and other cutting-edge technologies, aiming to provide solid scientific support and new research perspectives for the prevention and treatment of heart failure.

Engineered model of heart tissue repair for exploring fibrotic processes and therapeutic interventions

Advancements in human-engineered heart tissue have enhanced the understanding of cardiac cellular alteration. Nevertheless, a human model simulating pathological remodeling following myocardial infarction for therapeutic development remains essential. Here we develop an engineered model of myocardial repair that replicates the phased remodeling process, including hypoxic stress, fibrosis, and electrophysiological dysfunction. Transcriptomic analysis identifies nine critical signaling pathways related to cellular fate transitions, leading to the evaluation of seventeen modulators for their therapeutic potential in a mini-repair model. A scoring system quantitatively evaluates the restoration of abnormal electrophysiology, demonstrating that the phased combination of TGFβ inhibitor SB431542, Rho kinase inhibitor Y27632, and WNT activator CHIR99021 yields enhanced functional restoration compared to single factor treatments in both engineered and mouse myocardial infarction model. This engineered heart tissue repair model effectively captures the phased remodeling following myocardial infarction, providing a crucial platform for discovering therapeutic targets for ischemic heart disease.

Sustained amphiregulin expression in intermediate alveolar stem cells drives progressive fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal fibrotic disease. Recent studies have highlighted the persistence of an intermediate state of alveolar stem cells in IPF lungs. In this study, we discovered a close correlation between the distribution pattern of intermediate alveolar stem cells and the progression of fibrotic changes. We showed that amphiregulin (AREG) expression is significantly elevated in intermediate alveolar stem cells of mouse fibrotic lungs and IPF patients. High levels of serum AREG correlate significantly with profound deteriorations in lung function in IPF patients. We demonstrated that AREG in alveolar stem cells is both required and sufficient for activating EGFR in fibroblasts, thereby driving lung fibrosis. Moreover, pharmacological inhibition of AREG using a neutralizing antibody effectively blocked the initiation and progression of lung fibrosis in mice. Our study underscores the therapeutic potential of anti-AREG antibodies in attenuating IPF progression, offering a promising strategy for treating fibrotic diseases.

A composite patch loaded with 2-Deoxy Glucose facilitates cardiac recovery after myocardial infarction via attenuating local inflammatory response

Local inflammatory microenvironment in the early stage of myocardial infarction (MI) severely impaired cardiac recovery post-MI. Macrophages play a pivotal role in this process. A classical glycolytic inhibitor, 2-Deoxy-Glucose (2-DG), has been found to regulate the excessive pro-inflammatory macrophage polarization in the infarcted myocardium. This study investigated the effect of 2-DG-loaded chitosan/gelatin composite patch on the infarct microenvironment post-MI and its impact on cardiac repair. The results showed that the 2-DG patch significantly inhibited the expression of inflammatory cytokines, alleviated reactive oxygen species (ROS) accumulation, repressed the proinflammatory polarization of macrophages, attenuated local inflammatory microenvironment in the ischemic hearts, as well as improved cardiac function, reduced scar size, and promoted angiogenesis post-MI. In terms of mechanism, 2-DG exerts anti-inflammatory effects through inhibiting the NF-κB signaling pathway and reducing the assembly and activation of the NLRP3 inflammasome. These findings suggest that 2-DG composite patch may represent a promising therapeutic strategy for cardiac repair after MI.

DACT2 modulates atrial fibrillation through TGF/β and Wnt signaling pathways

Atrial fibrillation (AF) is a common cardiac arrhythmia that seriously affects the quality of life of patients. Effective treatment and prevention are important to control the morbidity and mortality of AF. It has been found that cardiac fibrosis promotes the onset and progression of AF. It is now known that transforming growth factor β (TGF-β), an important fibrotic cytokine, plays an important role in cardiac fibrosis by inducing myofibroblast activation via the activation of classical (SMAD-based) and non-classical (non-SMAD-based) signaling pathways. In addition, specific activation of the Wnt/β-catenin pathway has been shown to promote the transformation of fibroblasts into myofibroblasts. In recent years, a new family of proteins, namely Disheveled-associated antagonist of beta-catenin (DACT) 2, can affect the Wnt/β-catenin and TGF-β signaling pathways by regulating the phosphorylation levels of these target proteins, which in turn affects the progression of fibrosis. The present study focuses on the effect of DACT2-guided β-catenin on atrial fibrosis. It is expected that the summarized information can be helpful in the treatment of AF.

Role of TGFβ-producing regulatory T cells in scleroderma and end-stage organ failure

Regulatory T cells (Tregs) are crucial immune cells that initiate a tolerable immune response. Transforming growth factor-beta (TGFβ) is a key cytokine produced by Tregs and plays a significant role in stimulating tissue fibrosis. Systemic sclerosis, an autoimmune disease characterized by organ fibrosis, is associated with an overrepresentation of regulatory T cells. This review aims to identify Treg-dominant tolerable host immune reactions and discuss their association with scleroderma and end-stage organ failure. End-stage organ failures, including heart failure, liver cirrhosis, uremia, and pulmonary fibrosis, are frequently linked to tissue fibrosis. This suggests that TGFβ-producing Tregs are involved in the pathogenesis of these conditions. However, the exact significance of TGFβ and the mechanisms through which it induces tolerable immune reactions during end-stage organ failure remain unclear. A deeper understanding of these mechanisms could lead to improved preventive and therapeutic strategies for these severe diseases.

Ferroptosis in diabetic cardiomyopathy: Advances in cardiac fibroblast-cardiomyocyte interactions

Diabetic cardiomyopathy (DCM) is a common complication of diabetes, and its pathogenesis remains elusive. Ferroptosis, a process dependent on iron-mediated cell death, plays a crucial role in DCM via disrupted iron metabolism, lipid peroxidation, and weakened antioxidant defenses. Hyperglycemia, oxidative stress, and inflammation may exacerbate ferroptosis in diabetes. This review emphasizes the interaction between cardiac fibroblasts and cardiomyocytes in DCM, influencing ferroptosis occurrence. By exploring ferroptosis modulation for potential therapeutic targets, this article offers a fresh perspective on DCM treatment. The study systematically covers the interplay, mechanisms, and targeted drugs linked to ferroptosis in DCM development.

Comprehensive macro and micro views on immune cells in ischemic heart disease

Ischemic heart disease (IHD) is a prevalent cardiovascular condition that remains the primary cause of death due to its adverse ventricular remodelling and pathological changes in end-stage heart failure. As a complex pathologic condition, it involves intricate regulatory processes at the cellular and molecular levels. The immune system and cardiovascular system are closely interconnected, with immune cells playing a crucial role in maintaining cardiac health and influencing disease progression. Consequently, alterations in the cardiac microenvironment are influenced and controlled by various immune cells, such as macrophages, neutrophils, dendritic cells, eosinophils, and T-lymphocytes, along with the cytokines they produce. Furthermore, studies have revealed that Gata6+ pericardial cavity macrophages play a key role in regulating immune cell migration and subsequent myocardial tissue repair post IHD onset. This review outlines the role of immune cells in orchestrating inflammatory responses and facilitating myocardial repair following IHD, considering both macro and micro views. It also discusses innovative immune cell-based therapeutic strategies, offering new insights for further research on the pathophysiology of ischemic heart disease and immune cell-targeted therapy for IHD.

Spatial regulation of substrate adhesion directs fibroblast morphotype and phenotype

The switching of the fibroblast phenotype to myofibroblast is a hallmark of a wide variety of tissue pathologies. This phenotypical switch is known to be influenced not only by humoral factors such as TGF-β, but also by mechanical and physical cues in the cellular environment, and is accompanied by distinctive changes in cell morphology. However, the causative link between these cues, the concomitant morphological changes, and the resulting phenotypic switch remain elusive. Here, we use protein micropatterning to spatially control dermal fibroblast adhesion without invoking exogenous mechanical changes and demonstrate that varying the spatial configuration of focal adhesions (FAs) is sufficient to direct fibroblast phenotype. We further developed an automated morphometry analysis pipeline, which revealed FA eccentricity as the primary determinant of cell-state positioning along the spectrum of fibroblast phenotype. Moreover, linear fibronectin patterns that constrain the FAs were found to promote a further phenotype transition, characterized by dispersed expression of alpha-smooth muscle actin, pointing to an interesting possibility of controlling fibroblast phenotype beyond the canonical fibroblast-myofibroblast axis. Together, our study reveals that the spatial configuration of adhesion to the cellular microenvironment is a key factor governing fibroblast morphotype and phenotype, shedding new light on fibroblast phenotype regulation.

Macrophages in the infarcted heart acquire a fibrogenic phenotype, expressing matricellular proteins, but do not undergo fibroblast conversion

Although some studies have suggested that macrophages may secrete structural collagens, and convert to fibroblast-like cells, macrophage to fibroblast transdifferentiation in infarcted and remodeling hearts remains controversial. Our study uses linage tracing approaches and single cell transcriptomics to examine whether macrophages undergo fibroblast conversion, and to characterize the extracellular matrix expression profile of myeloid cells in myocardial infarction. To examine whether infarct macrophages undergo fibroblast conversion, we identified macrophage-derived progeny using the inducible CX3CR1CreER mice crossed with the PDGFRαEGFP reporter line for reliable fibroblast identification. The abundant fibroblasts that infiltrated the infarcted myocardium after 7 and 28 days of coronary occlusion were not derived from CX3CR1+ macrophages. Infarct macrophages retained myeloid cell characteristics and did not undergo conversion to myofibroblasts, endothelial or vascular mural cells. Single cell RNA-seq of CSF1R+ myeloid cells harvested from control and infarcted hearts showed no significant expression of fibroblast identity genes by myeloid cell clusters. Moreover, infarct macrophages did not express significant levels of genes encoding structural collagens. However, infarct macrophage and monocyte clusters were the predominant source of the fibrogenic growth factors Tgfb1 and Pdgfb, and of the matricellular proteins Spp1/Osteopontin, Thbs1/Thrombospondin-1, Emilin2, and Fn1/fibronectin, while expressing significant amounts of several other matrix genes, including Vcan/versican, Ecm1 and Sparc. ScRNA-seq data suggested similar patterns of matrix gene expression in human myocardial infarction. In conclusion, infarct macrophages do not undergo fibroblast or myofibroblast conversion and do not exhibit upregulation of structural collagens but may contribute to fibrotic remodeling by producing several fibrogenic matricellular proteins.

Fibroblast Smad7 Induction Protects the Remodeling Pressure-Overloaded Heart

BACKGROUND

Cardiac fibroblast activation contributes to adverse remodeling, fibrosis, and dysfunction in the pressure-overloaded heart. Although early fibroblast TGF-β (transforming growth factor-β)/Smad (small mother against decapentaplegic)-3 activation protects the pressure-overloaded heart by preserving the matrix, sustained TGF-β activation is deleterious, accentuating fibrosis and dysfunction. Thus, endogenous mechanisms that negatively regulate the TGF-β response in fibroblasts may be required to protect from progressive fibrosis and adverse remodeling. We hypothesized that Smad7, an inhibitory Smad that restrains TGF-β signaling, may be induced in the pressure-overloaded myocardium and may regulate fibrosis, remodeling, and dysfunction.

METHODS

The effects of myofibroblast-specific Smad7 loss were studied in a mouse model of transverse aortic constriction, using echocardiography, histological analysis, and molecular analysis. Proteomic studies in S7KO (Smad7 knockout) and overexpressing cells were used to identify fibroblast-derived mediators modulated by Smad7. In vitro experiments using cultured cardiac fibroblasts, fibroblasts populating collagen lattices, and isolated macrophages were used to dissect the molecular signals responsible for the effects of Smad7.

RESULTS

Following pressure overload, Smad7 was upregulated in cardiac myofibroblasts. TGF-β and angiotensin II stimulated fibroblast Smad7 upregulation via Smad3, whereas GDF15 (growth differentiation factor 15) induced Smad7 through GFRAL (glial cell line-derived neurotrophic factor family receptor α-like). MFS7KO (myofibroblast-specific S7KO) mice had increased mortality, accentuated systolic dysfunction and dilative remodeling, and accelerated diastolic dysfunction in response to transverse aortic constriction. Increased dysfunction in MFS7KO hearts was associated with accentuated fibrosis and increased MMP (matrix metalloproteinase)-2 activity and collagen denaturation. Secretomic analysis showed that Smad7 loss accentuates secretion of structural collagens and matricellular proteins and markedly increases MMP2 secretion. In contrast, Smad7 overexpression reduced MMP2 levels. In fibroblasts populating collagen lattices, the effects of Smad7 on fibroblast-induced collagen denaturation and pad contraction were partly mediated via MMP2 downregulation. Surprisingly, MFS7KO mice also exhibited significant macrophage expansion caused by paracrine actions of Smad7 null fibroblasts that stimulate macrophage proliferation and fibrogenic activation. Macrophage activation involved the combined effects of the fibroblast-derived matricellular proteins CD5L (CD5 antigen-like), SPARC (secreted protein acidic and rich in cysteine), CTGF (connective tissue growth factor), ECM1 (extracellular matrix protein 1), and TGFBI (TGFB induced).

CONCLUSIONS

The antifibrotic effects of Smad7 in the pressure-overloaded heart protect from dysfunction and involve not only reduction in collagen deposition but also suppression of MMP2-mediated matrix denaturation and paracrine effects that suppress macrophage activation through inhibition of matricellular proteins.

A Multifunctional Nanocomposite Hydrogel Delivery System Based on Dual-Loaded Liposomes for Scarless Wound Healing

Increased inflammatory responses and oxidative stress at the wound site following skin trauma impair healing. Furthermore, skin scarring places fibroblasts under severe mechanical stress and aggravates pathological fibrosis. A novel liposomal composite hydrogel is engineered for wound microenvironment remodeling, incorporating dual-loaded liposomes into gelatin methacrylate to create a nanocomposite hydrogel. Notably, tetrahydrocurcumin (THC) and hepatocyte growth factor (HGF) are encapsulated in the hydrophobic and hydrophilic layers of liposomes, respectively. The composite hydrogel maintains porous nanoarchitecture, demonstrating sustainable THC and HGF release and enhanced mechanical properties and biocompatibility. This system effectively promotes cell proliferation and angiogenesis and attenuates apoptosis. It decreases the expression of the inflammatory factors by inhibiting the high-mobility group box /receptor for advanced glycation end product/NF-κB (HMGB1/RAGE/NF-κB)pathway and increases macrophage polarization from M1 to M2 in vitro, effectively controlling inflammatory responses. It exhibits remarkable antioxidant properties by scavenging excess reactive oxygen species and free radicals. Most importantly, it effectively prevents scar formation by restraining the transforming growth factor beta (TGF-β)/Smads pathway that downregulates associated fibrotic factors. It demonstrates strong therapeutic effects against inflammation and fibrosis in a rat skin wound model with biosafety, advancing the development of innovative hydrogel-based therapeutic delivery strategies for clinical scarless wound therapy.

Integration mapping of cardiac fibroblast single-cell transcriptomes elucidates cellular principles of fibrosis in diverse pathologies

Single-cell technology has allowed researchers to probe tissue complexity and dynamics at unprecedented depth in health and disease. However, the generation of high-dimensionality single-cell atlases and virtual three-dimensional tissues requires integrated reference maps that harmonize disparate experimental designs, analytical pipelines, and taxonomies. Here, we present a comprehensive single-cell transcriptome integration map of cardiac fibrosis, which underpins pathophysiology in most cardiovascular diseases. Our findings reveal similarity between cardiac fibroblast (CF) identities and dynamics in ischemic versus pressure overload models of cardiomyopathy. We also describe timelines for commitment of activated CFs to proliferation and myofibrogenesis, profibrotic and antifibrotic polarization of myofibroblasts and matrifibrocytes, and CF conservation across mouse and human healthy and diseased hearts. These insights have the potential to inform knowledge-based therapies.

Inhibition of miR-25 ameliorates cardiac and skeletal muscle dysfunction in aged mdx/utrn haploinsufficient (+/-) mice

Dystrophic cardiomyopathy is a significant feature of Duchenne muscular dystrophy (DMD). Increased cardiomyocyte cytosolic calcium (Ca2+) and interstitial fibrosis are major pathophysiological hallmarks that ultimately result in cardiac dysfunction. MicroRNA-25 (miR-25) has been identified as a suppressor of both sarcoplasmic reticulum calcium ATPase 2a (SERCA2a) and mothers against decapentaplegic homolog-7 (Smad7) proteins. In this study, we created a gene transfer using an miR-25 tough decoy (TuD) RNA inhibitor delivered via recombinant adeno-associated virus serotype 9 (AAV9) to evaluate the effect of miR-25 inhibition on cardiac and skeletal muscle function in aged dystrophin/utrophin haploinsufficient mice mdx/utrn (+/-), a validated transgenic murine model of DMD. We found that the intravenous delivery of AAV9 miR-25 TuD resulted in strong and stable inhibition of cardiac miR-25 levels, together with the restoration of SERCA2a and Smad7 expression. This was associated with the amelioration of cardiomyocyte interstitial fibrosis as well as recovered cardiac function. Furthermore, the direct quadricep intramuscular injection of AAV9 miR-25 TuD significantly restored skeletal muscle Smad7 expression, reduced tissue fibrosis, and enhanced skeletal muscle performance in mdx/utrn (+/-) mice. These results imply that miR-25 TuD gene transfer may be a novel therapeutic approach to restore cardiomyocyte Ca2+ homeostasis and abrogate tissue fibrosis in DMD.

Repair of the Infarcted Heart: Cellular Effectors, Molecular Mechanisms and Therapeutic Opportunities

The adult mammalian heart has limited endogenous regenerative capacity and heals through the activation of inflammatory and fibrogenic cascades that ultimately result in the formation of a scar. After infarction, massive cardiomyocyte death releases a broad range of damage-associated molecular patterns that initiate both myocardial and systemic inflammatory responses. TLRs (toll-like receptors) and NLRs (NOD-like receptors) recognize damage-associated molecular patterns (DAMPs) and transduce downstream proinflammatory signals, leading to upregulation of cytokines (such as interleukin-1, TNF-α [tumor necrosis factor-α], and interleukin-6) and chemokines (such as CCL2 [CC chemokine ligand 2]) and recruitment of neutrophils, monocytes, and lymphocytes. Expansion and diversification of cardiac macrophages in the infarcted heart play a major role in the clearance of the infarct from dead cells and the subsequent stimulation of reparative pathways. Efferocytosis triggers the induction and release of anti-inflammatory mediators that restrain the inflammatory reaction and set the stage for the activation of reparative fibroblasts and vascular cells. Growth factor-mediated pathways, neurohumoral cascades, and matricellular proteins deposited in the provisional matrix stimulate fibroblast activation and proliferation and myofibroblast conversion. Deposition of a well-organized collagen-based extracellular matrix network protects the heart from catastrophic rupture and attenuates ventricular dilation. Scar maturation requires stimulation of endogenous signals that inhibit fibroblast activity and prevent excessive fibrosis. Moreover, in the mature scar, infarct neovessels acquire a mural cell coat that contributes to the stabilization of the microvascular network. Excessive, prolonged, or dysregulated inflammatory or fibrogenic cascades accentuate adverse remodeling and dysfunction. Moreover, inflammatory leukocytes and fibroblasts can contribute to arrhythmogenesis. Inflammatory and fibrogenic pathways may be promising therapeutic targets to attenuate heart failure progression and inhibit arrhythmia generation in patients surviving myocardial infarction.

Optimized new Shengmai powder inhibits myocardial fibrosis in heart failure by regulating the rat sarcoma/rapidly accelerated fibrosarcoma/mitogen-activated protein kinase kinase/extracellular regulated protein kinases signaling pathway

OBJECTIVE

Exploring the effect of Optimized New Shengmai powder (, ONSMP) on myocardial fibrosis in heart failure (HF) based on rat sarcoma (RAS)/rapidly accelerated fibrosarcoma (RAF)/mitogen-activated protein kinase kinase (MEK)/extracellular regulated protein kinases (ERK) signaling pathway.

METHODS

Randomized 70 Sprague-Dawley rats into sham (n = 10) and operation (n = 60) groups, then established the HF rat by ligating the left anterior descending branch of the coronary artery. We randomly divided the operation group rats into the model, ONSMP [including low (L), medium (M), and high (H) dose], and enalapril groups. After the 4-week drug intervention, echocardiography examines the cardiac function and calculates the ratios of the whole/left heart to the rat's body weight. Finally, we observed the degree of myocardial fibrosis by pathological sections, determined myocardium collagen (COL) I and COL Ⅲ content by enzyme-linked immunosorbent assay, detected the mRNA levels of COL I, COL Ⅲ, α-smooth muscle actin (α-SMA), and c-Fos proto-oncogene (c-Fos) by universal real-time, and detected the protein expression of p-RAS, p-RAF, p-MEK1/2, p-ERK1/2, p-ETS-like-1 transcription factor (p-ELK1), p-c-Fos, α-SMA, COL I, and COL Ⅲ by Western blot.

RESULTS

ONSMP can effectively improve HF rat's cardiac function, decrease cardiac organ coefficient, COL volume fraction, and COL I/Ⅲ content, down-regulate the mRNA of COL I/Ⅲ, α-SMA and c-Fos, and the protein of p-RAS, p-RAF, p-MEK1/ 2, p-ERK1/2, p-ELK1, c-Fos, COL Ⅰ/Ⅲ, and α-SMA.

CONCLUSIONS

ONSMP can effectively reduce myocardial fibrosis in HF rats, and the mechanism may be related to the inhibition of the RAS/RAF/MEK/ERK signaling pathway.

Macrophages in cardiovascular diseases: molecular mechanisms and therapeutic targets

The immune response holds a pivotal role in cardiovascular disease development. As multifunctional cells of the innate immune system, macrophages play an essential role in initial inflammatory response that occurs following cardiovascular injury, thereby inducing subsequent damage while also facilitating recovery. Meanwhile, the diverse phenotypes and phenotypic alterations of macrophages strongly associate with distinct types and severity of cardiovascular diseases, including coronary heart disease, valvular disease, myocarditis, cardiomyopathy, heart failure, atherosclerosis and aneurysm, which underscores the importance of investigating macrophage regulatory mechanisms within the context of specific diseases. Besides, recent strides in single-cell sequencing technologies have revealed macrophage heterogeneity, cell-cell interactions, and downstream mechanisms of therapeutic targets at a higher resolution, which brings new perspectives into macrophage-mediated mechanisms and potential therapeutic targets in cardiovascular diseases. Remarkably, myocardial fibrosis, a prevalent characteristic in most cardiac diseases, remains a formidable clinical challenge, necessitating a profound investigation into the impact of macrophages on myocardial fibrosis within the context of cardiac diseases. In this review, we systematically summarize the diverse phenotypic and functional plasticity of macrophages in regulatory mechanisms of cardiovascular diseases and unprecedented insights introduced by single-cell sequencing technologies, with a focus on different causes and characteristics of diseases, especially the relationship between inflammation and fibrosis in cardiac diseases (myocardial infarction, pressure overload, myocarditis, dilated cardiomyopathy, diabetic cardiomyopathy and cardiac aging) and the relationship between inflammation and vascular injury in vascular diseases (atherosclerosis and aneurysm). Finally, we also highlight the preclinical/clinical macrophage targeting strategies and translational implications.

The isoproterenol-induced myocardial fibrosis: A biochemical and histological investigation

The isoproterenol (ISO)-induced myocardial fibrosis is considered a reliable and repeatable experimental model characterized by a relatively low mortality rate. Although is well-known that ISO stimulates the β1 adrenergic receptors at the myocardial level, a high degree of heterogeneity emerges around the doses and duration of the treatment generating unclear results. Therefore, we propose to gain insights into the progression of ISO-induced myocardial fibrosis, in order to critically analyze and optimize the experimental model. Male Wistar rats (12-14-week-old) were submitted to subcutaneous injection of ISO, in particular, two doses were selected: the commonly used dose of 5 mg/kg and a lower dose of 1 mg/kg, administered for 3 and 6 days. Biochemical and histological examinations were conducted either immediately after the last administration or after a recovering period of 7 or 14 days from the initial administration. Noteworthy, from our investigation emerged that even the lower dose of ISO was able to induce the maximal biochemical and histological alterations, suggesting that lower doses should be considered to control the progression of the damage more precisely and to identify a prodromic phase in which intervention with pharmacological or nutraceutical tools can be effectively attempted.

Macrophages promote the transition from myocardial ischemia reperfusion injury to cardiac fibrosis in mice through GMCSF/CCL2/CCR2 and phenotype switching

Following acute myocardial ischemia reperfusion (MIR), macrophages infiltrate damaged cardiac tissue and alter their polarization phenotype to respond to acute inflammation and chronic fibrotic remodeling. In this study we investigated the role of macrophages in post-ischemic myocardial fibrosis and explored therapeutic targets for myocardial fibrosis. Male mice were subjected to ligation of the left coronary artery for 30 min. We first detected the levels of chemokines in heart tissue that recruited immune cells infiltrating into the heart, and found that granulocyte-macrophage colony-stimulating factor (GMCSF) released by mouse cardiac microvascular endothelial cells (MCMECs) peaked at 6 h after reperfusion, and c-c motif chemokine ligand 2 (CCL2) released by GMCSF-induced macrophages peaked at 24 h after reperfusion. In co-culture of BMDMs with MCMECs, we demonstrated that GMCSF derived from MCMECs stimulated the release of CCL2 by BMDMs and effectively promoted the migration of BMDMs. We also confirmed that GMCSF promoted M1 polarization of macrophages in vitro, while GMCSF neutralizing antibodies (NTABs) blocked CCL2/CCR2 signaling. In MIR mouse heart, we showed that GMCSF activated CCL2/CCR2 signaling to promote NLRP3/caspase-1/IL-1β-mediated and amplified inflammatory damage. Knockdown of CC chemokine receptor 2 gene (CCR2-/-), or administration of specific CCR2 inhibitor RS102895 (5 mg/kg per 12 h, i.p., one day before MIR and continuously until the end of the experiment) effectively reduced the area of myocardial infarction, and down-regulated inflammatory mediators and NLRP3/Caspase-1/IL-1β signaling. Mass cytometry confirmed that M2 macrophages played an important role during fibrosis, while macrophage-depleted mice exhibited significantly reduced transforming growth factor-β (Tgf-β) levels in heart tissue after MIR. In co-culture of macrophages with fibroblasts, treatment with recombinant mouse CCL2 stimulated macrophages to release a large amount of Tgf-β, and promoted the release of Col1α1 by fibroblasts. This effect was diminished in BMDMs from CCR2-/- mice. After knocking out or inhibiting CCR2-gene, the levels of Tgf-β were significantly reduced, as was the level of myocardial fibrosis, and cardiac function was protected. This study confirms that the acute injury to chronic fibrosis transition after MIR in mice is mediated by GMCSF/CCL2/CCR2 signaling in macrophages through NLRP3 inflammatory cascade and the phenotype switching.

Role and molecular mechanisms of SGLT2 inhibitors in pathological cardiac remodeling (Review)

Cardiovascular diseases are caused by pathological cardiac remodeling, which involves fibrosis, inflammation and cell dysfunction. This includes autophagy, apoptosis, oxidative stress, mitochondrial dysfunction, changes in energy metabolism, angiogenesis and dysregulation of signaling pathways. These changes in heart structure and/or function ultimately result in heart failure. In an effort to prevent this, multiple cardiovascular outcome trials have demonstrated the cardiac benefits of sodium‑glucose cotransporter type 2 inhibitors (SGLT2is), hypoglycemic drugs initially designed to treat type 2 diabetes mellitus. SGLT2is include empagliflozin and dapagliflozin, which are listed as guideline drugs in the 2021 European Guidelines for Heart Failure and the 2022 American Heart Association/American College of Cardiology/Heart Failure Society of America Guidelines for Heart Failure Management. In recent years, multiple studies using animal models have explored the mechanisms by which SGLT2is prevent cardiac remodeling. This article reviews the role of SGLT2is in cardiac remodeling induced by different etiologies to provide a guideline for further evaluation of the mechanisms underlying the inhibition of pathological cardiac remodeling by SGLT2is, as well as the development of novel drug targets.

Epigenetic regulation of TGF-β pathway and its role in radiation response

PURPOSE

Transforming growth factor (TGF-β) plays a dual role in tumor progression as well as a pivotal role in radiation response. TGF-β-related epigenetic regulations, including DNA methylation, histone modifications (including methylation, acetylation, phosphorylation, ubiquitination), chromatin remodeling and non-coding RNA regulation, have been found to affect the occurrence and development of tumors as well as their radiation response in multiple dimensions. Due to the significance of radiotherapy in tumor treatment and the essential roles of TGF-β signaling in radiation response, it is important to better understand the role of epigenetic regulation mechanisms mediated by TGF-β signaling pathways in radiation-induced targeted and non-targeted effects.

CONCLUSIONS

By revealing the epigenetic mechanism related to TGF-β-mediated radiation response, summarizing the existing relevant adjuvant strategies for radiotherapy based on TGF-β signaling, and discovering potential therapeutic targets, we hope to provide a new perspective for improving clinical treatment.

The role of matrix metalloproteinase 9 in fibrosis diseases and its molecular mechanisms

Fibrosis is a process of tissue repair that results in the slow creation of scar tissue to replace healthy tissue and can affect any tissue or organ. Its primary feature is the massive deposition of extracellular matrix (mainly collagen), eventually leading to tissue dysfunction and organ failure. The progression of fibrotic diseases has put a significant strain on global health and the economy, and as a result, there is an urgent need to find some new therapies. Previous studies have identified that inflammation, oxidative stress, some cytokines, and remodeling play a crucial role in fibrotic diseases and are essential avenues for treating fibrotic diseases. Among them, matrix metalloproteinases (MMPs) are considered the main targets for the treatment of fibrotic diseases since they are the primary driver involved in ECM degradation, and tissue inhibitors of metalloproteinases (TIMPs) are natural endogenous inhibitors of MMPs. Through previous studies, we found that MMP-9 is an essential target for treating fibrotic diseases. However, it is worth noting that MMP-9 plays a bidirectional regulatory role in different fibrotic diseases or different stages of the same fibrotic disease. Previously identified MMP-9 inhibitors, such as pirfenidone and nintedanib, suffer from some rather pronounced side effects, and therefore, there is an urgent need to investigate new drugs. In this review, we explore the mechanism of action and signaling pathways of MMP-9 in different tissues and organs, hoping to provide some ideas for developing safer and more effective biologics.

Inhibitory effect of microRNA-21 on pathways and mechanisms involved in cardiac fibrosis development

Cardiac fibrosis is a pivotal cardiovascular disease (CVD) process and represents a notable health concern worldwide. While the complex mechanisms underlying CVD have been widely investigated, recent research has highlighted microRNA-21's (miR-21) role in cardiac fibrosis pathogenesis. In this narrative review, we explore the molecular interactions, focusing on the role of miR-21 in contributing to cardiac fibrosis. Various signaling pathways, such as the RAAS, TGF-β, IL-6, IL-1, ERK, PI3K-Akt, and PTEN pathways, besides dysregulation in fibroblast activity, matrix metalloproteinases (MMPs), and tissue inhibitors of MMPs cause cardiac fibrosis. Besides, miR-21 in growth factor secretion, apoptosis, and endothelial-to-mesenchymal transition play crucial roles. miR-21 capacity regulatory function presents promising insights for cardiac fibrosis. Moreover, this review discusses numerous approaches to control miR-21 expression, including antisense oligonucleotides, anti-miR-21 compounds, and Notch signaling modulation, all novel methods of cardiac fibrosis inhibition. In summary, this narrative review aims to assess the molecular mechanisms of cardiac fibrosis and its essential miR-21 function.

Known pathogenic gene variants and new candidates detected in Sudden Unexpected Infant Death using Whole Genome Sequencing

Purpose

To gain insights into potential genetic factors contributing to the infant's vulnerability to Sudden Unexpected Infant Death (SUID).

Methods

Whole Genome Sequencing (WGS) was performed on 145 infants that succumbed to SUID, and 576 healthy adults. Variants were filtered by gnomAD allele frequencies and predictions of functional consequences.

Results

Variants of interest were identified in 86 genes, 63.4% of our cohort. Seventy-one of these have been previously associated with SIDS/SUID/SUDP. Forty-three can be characterized as cardiac genes and are related to cardiomyopathies, arrhythmias, and other conditions. Variants in 22 genes were associated with neurologic functions. Variants were also found in 13 genes reported to be pathogenic for various systemic disorders. Variants in eight genes are implicated in the response to hypoxia and the regulation of reactive oxygen species (ROS) and have not been previously described in SIDS/SUID/SUDP. Seventy-two infants met the triple risk hypothesis criteria (Figure 1).

Conclusion

Our study confirms and further expands the list of genetic variants associated with SUID. The abundance of genes associated with heart disease and the discovery of variants associated with the redox metabolism have important mechanistic implications for the pathophysiology of SUID.

Protective effects of macrophage-specific integrin α5 in myocardial infarction are associated with accentuated angiogenesis

Macrophages sense changes in the extracellular matrix environment through the integrins and play a central role in regulation of the reparative response after myocardial infarction. Here we show that macrophage integrin α5 protects the infarcted heart from adverse remodeling and that the protective actions are associated with acquisition of an angiogenic macrophage phenotype. We demonstrate that myeloid cell- and macrophage-specific integrin α5 knockout mice have accentuated adverse post-infarction remodeling, accompanied by reduced angiogenesis in the infarct and border zone. Single cell RNA-sequencing identifies an angiogenic infarct macrophage population with high Itga5 expression. The angiogenic effects of integrin α5 in macrophages involve upregulation of Vascular Endothelial Growth Factor A. RNA-sequencing of the macrophage transcriptome in vivo and in vitro followed by bioinformatic analysis identifies several intracellular kinases as potential downstream targets of integrin α5. Neutralization assays demonstrate that the angiogenic actions of integrin α5-stimulated macrophages involve activation of Focal Adhesion Kinase and Phosphoinositide 3 Kinase cascades.

[Smeglutide inhibits high glucose-induced proliferation of myocardial fibroblasts by downregulating TGFβ/Smad3 signaling]

OBJECTIVE

To investigate the effect of semaglutide on high glucose-induced proliferation of cardiac fibroblasts (CFs) and explore its possible mechanism.

METHODS

Primary mouse CFs, identified by detecting vimentin expression, were stimulated with 25 mmol/L and treated with 5-20 nmol/L semaglutide, and the cell proliferation was examined with CKK-8 assay for concentration screening.Cultured CFs exposed to high glucose (25 mmol/L) were treated with 5 nmol/L semaglutide, and the changes in cell cycle were detected using Cell Cycle Staining Kit; The mRNA expressions of α-smooth muscle actin (α-SMA), transforming growth factor-β1(TGF-β1) and Smad3 were detected using RT-qPCR, and the levels of type Ⅰ collagen (CoLⅠ) and type Ⅲ collagen (CoLIII) in the cell cultures were determined with ELISA.

RESULTS

Compared with the control cells, the CFs cultured in high glucose exhibited significantly enhanced proliferative activity (P<0.05) with increased percentage of S-phase cells.Semagutide treatment obviously inhibited high glucose-induced proliferation of the CFs (P<0.05) and reduced the percentage of S-phase cells.High glucose stimulation significantly increased the mRNA expressions of α-SMA, CoL Ⅰ and CoLIII in the cells (P<0.01), which were effectively lowered by semaglutide treatment (P<0.01).The expressions of TGF-β1 and Smad3 were significantly increased in high glucose-stimulated CFs (P<0.01) and were lowered by semaglutide treatment (P<0.01).

CONCLUSION

Semaglutide can inhibit high glucose-induced proliferation and collagen synthesis in mouse CFs possibly by downregulating the TGFβ/Smad3 signaling pathway.

CircMACF1 alleviates myocardial fibrosis after acute myocardial infarction by suppressing cardiac fibroblast activation via the miR-16-5p/SMAD7 axis

Circular RNAs (circRNAs) played a pivotal role in myocardial fibrosis after acute myocardial infarction (AMI). The activation of cardiac fibroblasts (CFs) and accumulation of extracellular matrix are the main characteristics of myocardial fibrosis. In our research, we aimed to elucidate the functional roles of circMACF1 in CF activation after AMI as well as the underlying mechanism. Human CFs were activated by TGF-β1 treatment. qPCR and western blotting were performed to investigate gene and protein expression. CCK-8 and transwell assays were carried out to measure cell proliferation, and migration. Immunofluorescence was used to investigate α-SMA level. The interaction between miR-16-5p and circMACF1 or SMAD7 was revealed by RIP or dual luciferase reporter gene assays. CircMACF1 and SMAD7 were repressed in AMI patients and CFs treated with TGF-β1, and miR-16-5p was increased. In addition, circMACF1 was resistant to RNase R and abundantly expressed in the cytoplasm. Overexpression of circMACF1 inhibited cell proliferation and migration and reduced the expression levels of fibrosis-related proteins, including Collagen I, Collagen III, and α-SMA. Furthermore, circMCAF1 could directly bind to miR-16-5p, and SMAD7 was a target gene of miR-16-5p. Knockdown of miR-16-5p suppressed the activation, proliferation, and migration of TGF-β1-treated CFs, but silencing circMACF1 or SMAD7 partially reversed this phenomenon. CircMACF1 attenuated the TGF-β1-induced activation, proliferation and migration of CFs via the miR-16-5p/SMAD7 signaling pathway, indicating that circMACF1 might be a new therapeutic target for AMI.

Comparative Analysis of Heart Regeneration: Searching for the Key to Heal the Heart-Part II: Molecular Mechanisms of Cardiac Regeneration

Cardiovascular diseases are the leading cause of death worldwide, among which ischemic heart disease is the most representative. Myocardial infarction results from occlusion of a coronary artery, which leads to an insufficient blood supply to the myocardium. As it is well known, the massive loss of cardiomyocytes cannot be solved due the limited regenerative ability of the adult mammalian hearts. In contrast, some lower vertebrate species can regenerate the heart after an injury; their study has disclosed some of the involved cell types, molecular mechanisms and signaling pathways during the regenerative process. In this 'two parts' review, we discuss the current state-of-the-art of the main response to achieve heart regeneration, where several processes are involved and essential for cardiac regeneration.

1821-2021: Contributions of physicians and researchers of Greek descent in the advancement of clinical and experimental cardiology and cardiac surgery

While the role of Greeks in the development of early western medicine is well-known and appreciated, the contributions of modern Greek medical practitioners are less known and often overlooked. On the occasion of the 200-year anniversary of the Greek War of Independence, this review article sheds light onto the achievements of modern scientists of Greek descent in the development of cardiology, cardiac surgery, and cardiovascular research, through a short history of the development of these fields and of the related institutions in Greece. In the last decades, the Greek cardiology and Cardiac Surgery communities have been active inside and outside Greece and have a remarkable presence internationally, particularly in the United States. This article highlights the ways in which Greek cardiology and cardiovascular research has been enriched by absorbing knowledge produced in international medical centers, academic institutes and pharmaceutical industries in which generations of Greek doctors and researchers trained prior to their return to the homeland; it also highlights the achievements of medical practitioners and researchers of Greek descent who excelled abroad, producing ground-breaking work that has left a permanent imprint on global medicine.

Genetic and pharmacological inhibition of METTL3 alleviates renal fibrosis by reducing EVL m6A modification through an IGF2BP2-dependent mechanism

BACKGROUND

N6 -methyladenosine (m6A) is of great importance in renal physiology and disease progression, but its function and mechanism in renal fibrosis remain to be comprehensively and extensively explored. Hence, this study will explore the function and potential mechanism of critical regulator-mediated m6A modification during renal fibrosis and thereby explore promising anti-renal fibrosis agents.

METHODS

Renal tissues from humans and mice as well as HK-2 cells were used as research subjects. The profiles of m6A modification and regulators in renal fibrosis were analysed at the protein and RNA levels using Western blotting, quantitative real-time polymerase chain reaction and other methods. Methylation RNA immunoprecipitation sequencing and RNA sequencing coupled with methyltransferase-like 3 (METTL3) conditional knockout were used to explore the function of METTL3 and potential targets. Gene silencing and overexpression combined with RNA immunoprecipitation were performed to investigate the underlying mechanism by which METTL3 regulates the Ena/VASP-like (EVL) m6A modification that promotes renal fibrosis. Molecular docking and virtual screening with in vitro and in vivo experiments were applied to screen promising traditional Chinese medicine (TCM) monomers and explore their mechanism of regulating the METTL3/EVL m6A axis and anti-renal fibrosis.

RESULTS

METTL3 and m6A modifications were hyperactivated in both the tubular region of fibrotic kidneys and HK-2 cells. Upregulated METTL3 enhanced the m6A modification of EVL mRNA to improve its stability and expression in an insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2)-dependent manner. Highly expressed EVL binding to Smad7 abrogated the Smad7-induced suppression of transforming growth factor-β (TGF-β1)/Smad3 signal transduction, which conversely facilitated renal fibrosis progression. Molecular docking and virtual screening based on the structure of METTL3 identified a TCM monomer named isoforsythiaside, which inhibited METTL3 activity together with the METTL3/EVL m6A axis to exert anti-renal fibrosis effects.

CONCLUSIONS

Collectively, the overactivated METTL3/EVL m6A axis is a potential target for renal fibrosis therapy, and the pharmacological inhibition of METTL3 activity by isoforsythiaside suggests that it is a promising anti-renal fibrosis agent.

Identification of TGF-β-related genes in cardiac hypertrophy and heart failure based on single cell RNA sequencing

BACKGROUND

Heart failure (HF) remains a huge medical burden worldwide. Pathological cardiac hypertrophy is one of the most significant phenotypes of HF. Several studies have reported that the TGF-β pathway plays a double-sided role in HF. Therefore, TGF-β-related genes (TRGs) may be potential therapeutic targets for cardiac hypertrophy and HF. However, the roles of TRGs in HF at the single-cell level remain unclear.

METHOD

In this study, to analyze the expression pattern of TRGs during the progress of cardiac hypertrophy and HF, we used three public single-cell RNA sequencing datasets for HF (GSE161470, GSE145154, and GSE161153), one HF transcriptome data (GSE57338), and one hypertrophic cardiomyopathy transcriptome data (GSE141910). Weighted gene co-expression network analysis (WGCNA), functional enrichment analysis and machine learning algorithms were used to filter hub genes. Transverse aortic constriction mice model, CCK-8, wound healing assay, quantitative real-time PCR and western blotting were used to validate bioinformatics results.

RESULTS

We observed that cardiac fibroblasts (CFs) and endothelial cells showed high TGF-β activity during the progress of HF. Three modules (royalblue, brown4, and darkturquoize) were identified to be significantly associated with TRGs in HF. Six hub genes (TANC2, ADAMTS2, DYNLL1, MRC2, EGR1, and OTUD1) showed anomaly trend in cardiac hypertrophy. We further validated the regulation of the TGF-β-MYC-ADAMTS2 axis on CFs activation in vitro.

CONCLUSIONS

This study identified six hub genes (TANC2, ADAMTS2, DYNLL1, MRC2, EGR1, and OTUD1) by integrating scRNA and transcriptome data. These six hub genes might be therapeutic targets for cardiac hypertrophy and HF.

The Chemistry and Biology of Collagen Hybridization

Collagen provides mechanical and biological support for virtually all human tissues in the extracellular matrix (ECM). Its defining molecular structure, the triple-helix, could be damaged and denatured in disease and injuries. To probe collagen damage, the concept of collagen hybridization has been proposed, revised, and validated through a series of investigations reported as early as 1973: a collagen-mimicking peptide strand may form a hybrid triple-helix with the denatured chains of natural collagen but not the intact triple-helical collagen proteins, enabling assessment of proteolytic degradation or mechanical disruption to collagen within a tissue-of-interest. Here we describe the concept and development of collagen hybridization, summarize the decades of chemical investigations on rules underlying the collagen triple-helix folding, and discuss the growing biomedical evidence on collagen denaturation as a previously overlooked ECM signature for an array of conditions involving pathological tissue remodeling and mechanical injuries. Finally, we propose a series of emerging questions regarding the chemical and biological nature of collagen denaturation and highlight the diagnostic and therapeutic opportunities from its targeting.

Integrated bioinformatics and machine learning algorithms reveal the critical cellular senescence-associated genes and immune infiltration in heart failure due to ischemic cardiomyopathy

Heart failure (HF) is the final stage of many cardiovascular illnesses and the leading cause of death worldwide. At the same time, ischemic cardiomyopathy has replaced valvular heart disease and hypertension as the primary causes of heart failure. Cellular senescence in heart failure is currently receiving more attention. In this paper, we investigated the correlation between the immunological properties of myocardial tissue and the pathological mechanisms of cellular senescence during ischemic cardiomyopathy leading to heart failure (ICM-HF) using bioinformatics and machine learning methodologies. Our goals were to clarify the pathogenic causes of heart failure and find new treatment options. First, after obtaining GSE5406 from the Gene Expression Omnibus (GEO) database and doing limma analysis, differential genes (DEGs) among the ICM-HF and control groups were identified. We intersected these differential genes with cellular senescence-associated genes (CSAG) via the CellAge database to obtain 39 cellular senescence-associated DEGs (CSA-DEGs). Then, a functional enrichment analysis was performed to elucidate the precise biological processes by which the hub genes control cellular senescence and immunological pathways. Then, the respective key genes were identified by Random Forest (RF) method, LASSO (Least Absolute Shrinkage and Selection Operator) algorithms, and Cytoscape's MCODE plug-in. Three sets of key genes were taken to intersect to obtain three CSA-signature genes (including MYC, MAP2K1, and STAT3), and these three CSA-signature genes were validated in the test gene set (GSE57345), and Nomogram analysis was done. In addition, we assessed the relationship between these three CSA- signature genes and the immunological landscape of heart failure encompassing immunological infiltration expression profiles. This work implies that cellular senescence may have a crucial role in the pathogenesis of ICM-HF, which may be closely tied to its effect on the immune microenvironment. Exploring the molecular underpinnings of cellular senescence during ICM-HF is anticipated to yield significant advances in the disease's diagnosis and therapy.

The phagocytic role of macrophage following myocardial infarction

Myocardial infarction (MI) is one of the cardiovascular diseases with high morbidity and mortality. MI causes large amounts of apoptotic and necrotic cells that need to be efficiently and instantly engulfed by macrophage to avoid second necrosis. Phagocytic macrophages can dampen or resolve inflammation to protect infarcted heart. Phagocytosis of macrophages is modulated by various factors including proteins, receptors, lncRNA and cytokines. A better understanding of mechanisms in phagocytosis will be beneficial to regulate macrophage phagocytosis capability towards a desired direction in cardioprotection after MI. In this review, we describe the phagocytosis effect of macrophages and summarize the latest reported signals regulating phagocytosis after MI, which will provide a new thinking about phagocytosis-dependent cardiac protection after MI.

Vitamin C Regulates the Profibrotic Activity of Fibroblasts in In Vitro Replica Settings of Myocardial Infarction

Extracellular collagen remodeling is one of the central mechanisms responsible for the structural and compositional coherence of myocardium in patients undergoing myocardial infarction (MI). Activated primary cardiac fibroblasts following myocardial infarction are extensively investigated to establish anti-fibrotic therapies to improve left ventricular remodeling. To systematically assess vitamin C functions as a potential modulator involved in collagen fibrillogenesis in an in vitro model mimicking heart tissue healing after MI. Mouse primary cardiac fibroblasts were isolated from wild-type C57BL/6 mice and cultured under normal and profibrotic (hypoxic + transforming growth factor beta 1) conditions on freshly prepared coatings mimicking extracellular matrix (ECM) remodeling during healing after an MI. At 10 μg/mL, vitamin C reprogramed the respiratory mitochondrial metabolism, which is effectively associated with a more increased accumulation of intracellular reactive oxygen species (iROS) than the number of those generated by mitochondrial reactive oxygen species (mROS). The mRNA/protein expression of subtypes I, III collagen, and fibroblasts differentiations markers were upregulated over time, particularly in the presence of vitamin C. The collagen substrate potentiated the modulator role of vitamin C in reinforcing the structure of types I and III collagen synthesis by reducing collagen V expression in a timely manner, which is important in the initiation of fibrillogenesis. Altogether, our study evidenced the synergistic function of vitamin C at an optimum dose on maintaining the equilibrium functionality of radical scavenger and gene transcription, which are important in the initial phases after healing after an MI, while modulating the synthesis of de novo collagen fibrils, which is important in the final stage of tissue healing.

Post-myocardial infarction fibrosis: Pathophysiology, examination, and intervention

Cardiac fibrosis plays an indispensable role in cardiac tissue homeostasis and repair after myocardial infarction (MI). The cardiac fibroblast-to-myofibroblast differentiation and extracellular matrix collagen deposition are the hallmarks of cardiac fibrosis, which are modulated by multiple signaling pathways and various types of cells in time-dependent manners. Our understanding of the development of cardiac fibrosis after MI has evolved in basic and clinical researches, and the regulation of fibrotic remodeling may facilitate novel diagnostic and therapeutic strategies, and finally improve outcomes. Here, we aim to elaborate pathophysiology, examination and intervention of cardiac fibrosis after MI.

Diabetes Induces Cardiac Fibroblast Activation, Promoting a Matrix-Preserving Nonmyofibroblast Phenotype, Without Stimulating Pericyte to Fibroblast Conversion

Background Interstitial and perivascular fibrosis may contribute to diabetes-associated heart failure. Pericytes can convert to fibroblasts under conditions of stress and have been implicated in the pathogenesis of fibrotic diseases. We hypothesized that in diabetic hearts, pericytes may convert to fibroblasts, contributing to fibrosis and to the development of diastolic dysfunction. Methods and Results Using pericyte:fibroblast dual reporter (NG2^Dsred [neuron-glial antigen 2 red fluorescent protein variant]; PDGFRα^EGFP [platelet-derived growth factor receptor alpha enhanced green fluorescent protein]) mice in a type 2 diabetic db/db background, we found that diabetes does not significantly affect pericyte density but reduces the myocardial pericyte:fibroblast ratio. Lineage tracing using the inducible NG2^CreER driver, along with reliable labeling of fibroblasts with the PDGFRα reporter system, showed no significant pericyte to fibroblast conversion in lean and db/db hearts. In addition, db/db mouse cardiac fibroblasts did not undergo myofibroblast conversion and had no significant induction of structural collagens but exhibited a matrix-preserving phenotype, associated with increased expression of antiproteases, matricellular genes, matrix cross-linking enzymes, and the fibrogenic transcription factor cMyc. In contrast, db/db mouse cardiac pericytes had increased expression of Timp3, without any changes in expression of other fibrosis-associated genes. The matrix-preserving phenotype of diabetic fibroblasts was associated with induction of genes encoding oxidative (Ptgs2/cycloxygenase-2, and Fmo2) and antioxidant proteins (Hmox1, Sod1). In vitro, high glucose partially recapitulated the in vivo changes in diabetic fibroblasts. Conclusions Diabetic fibrosis is not mediated through pericyte to fibroblast conversion but involves acquisition of a matrix-preserving fibroblast program, which is independent of myofibroblast conversion and is only partially explained by the effects of the hyperglycemic environment.

The role of SMAD signaling in hypertrophic obstructive cardiomyopathy: an immunohistopathological study in pediatric and adult patients

Hypertrophic obstructive cardiomyopathy (HOCM) can bring a high risk of sudden cardiac death in young people. It is particularly urgent to understand the development and mechanism of HOCM to prevent unsafe incidents. Here, the comparison between pediatric and adult patients with HOCM has been performed to uncover the signaling mechanism regulating pathological process through histopathological analysis and immunohistochemical analysis. We found SMAD proteins played an important role during myocardial fibrosis for HOCM patients. In patients with HOCM, Masson and HE staining showed that myocardial cells were diffusely hypertrophied with obvious disorganized myocardial fiber alignment, and myocardial tissue was more damaged and collagen fibers increased significantly, which come early in childhood. Increased expressions of SMAD2 and SMAD3 contributed to myocardial fibrosis in patients with HOCM, which happened early in childhood and continued through adulthood. In addition, decreased expression of SMAD7 was closely related to collagen deposition, which negatively expedited fibrotic responses in patients with HOCM. Our study indicated that the abnormal regulation of SMAD signaling pathway can lead to severe myocardial fibrosis in childhood and its fibrogenic effects persist into adulthood, which is a crucial factor in causing sudden cardiac death and heart failure in HOCM patients.

Targeting myeloid cell coagulation signaling blocks MAP kinase/TGF-β1-driven fibrotic remodeling in ischemic heart failure

Despite major advances in acute interventions for myocardial infarction (MI), adverse cardiac remodeling and excess fibrosis after MI causing ischemic heart failure (IHF) remain a leading cause of death worldwide. Here we identify a profibrotic coagulation signaling pathway that can be targeted for improved cardiac function following MI with persistent ischemia. Quantitative phosphoproteomics of cardiac tissue revealed an upregulated mitogen-activated protein kinase (MAPK) pathway in human IHF. Intervention in this pathway with trametinib improves myocardial function and prevents fibrotic remodeling in a murine model of non-reperfused MI. MAPK activation in MI requires myeloid cell signaling of protease-activated receptor 2 linked to the cytoplasmic domain of the coagulation initiator tissue factor (TF). They act upstream of pro-oxidant NOX2 NADPH oxidase, ERK1/2 phosphorylation, and activation of profibrotic TGF-β1. Specific targeting with the TF inhibitor nematode anticoagulant protein c2 (NAPc2) starting 1 day after established experimental MI averts IHF. Increased TF cytoplasmic domain phosphorylation in circulating monocytes from patients with subacute MI identifies a potential thromboinflammatory biomarker reflective of increased risk for IHF and suitable for patient selection to receive targeted TF inhibition therapy.

Mechanism of action of non-coding RNAs and traditional Chinese medicine in myocardial fibrosis: Focus on the TGF-β/Smad signaling pathway

Cardiac fibrosis is a serious public health problem worldwide that is closely linked to progression of many cardiovascular diseases (CVDs) and adversely affects both the disease process and clinical prognosis. Numerous studies have shown that the TGF-β/Smad signaling pathway plays a key role in the progression of cardiac fibrosis. Therefore, targeted inhibition of the TGF-β/Smad signaling pathway may be a therapeutic measure for cardiac fibrosis. Currently, as the investigation on non-coding RNAs (ncRNAs) move forward, a variety of ncRNAs targeting TGF-β and its downstream Smad proteins have attracted high attention. Besides, Traditional Chinese Medicine (TCM) has been widely used in treating the cardiac fibrosis. As more and more molecular mechanisms of natural products, herbal formulas, and proprietary Chinese medicines are revealed, TCM has been proven to act on cardiac fibrosis by modulating multiple targets and signaling pathways, especially the TGF-β/Smad. Therefore, this work summarizes the roles of TGF-β/Smad classical and non-classical signaling pathways in the cardiac fibrosis, and discusses the recent research advances in ncRNAs targeting the TGF-β/Smad signaling pathway and TCM against cardiac fibrosis. It is hoped, in this way, to give new insights into the prevention and treatment of cardiac fibrosis.

MicroRNA-30e-3p reduces coronary microembolism-induced cardiomyocyte pyroptosis and inflammation by sequestering HDAC2 from the SMAD7 promoter

This study investigates the mechanism by which microRNA (miR)-30e-3p reduces coronary microembolism (CME)-induced cardiomyocyte pyroptosis and inflammation. Cardiac function tests, histological staining, and transmission electron microscopy were performed on CME-model rats injected with adeno-associated viral vectors. Cardiomyocytes were transfected 24 h before a cellular model of pyroptosis was established via treatment with 1 μg/mL lipopolysaccharide (LPS) for 4 h and 5 mM ATP for 30 min. Pyroptosis, inflammation, and Wnt/β-catenin signaling in cardiomyocytes were detected. Dual-luciferase reporter assays and/or RNA pull-down assays were performed to verify the binding of miR-30e-3p to HDAC2 mRNA or HDAC2 to the SMAD7 promoter. Chromatin immunoprecipitation was used to assess the level of H3K27 acetylation at the SMAD7 promoter. miR-30e-3p and SMAD7 expression levels were downregulated and HDAC2 expression was upregulated with CME. The overexpression of miR-30e-3p restored cardiac functions in CME-model rats and reduced serum cTnI, IL-18, and IL-1β levels, microinfarcts, inflammatory cell infiltration, apoptosis, collagen content, and GSDMD-N, cleaved caspase-1, and NLRP3 expression in the myocardium, but these effects were reversed by SMAD7 knockdown. The overexpression of miR-30e-3p or knockdown of HDAC2 reduced LDH, IL-18, and IL-1β secretion, propidium iodide intake, and GSDMD-N, NLRP3, cleaved caspase-1, Wnt3a, Wnt5a, and β-catenin expression in the cardiomyocyte model. miR-30e-3p inhibited the expression of HDAC2 by binding HDAC2 mRNA. HDAC2 repressed the expression of SMAD7 by catalyzing H3K27 deacetylation at the SMAD7 promoter. miR-30e-3p, by binding HDAC2 to promote SMAD7 expression, reduces CME-induced cardiomyocyte pyroptosis and inflammation.

Feasibility and mechanism analysis of Reduning in the prevention of sepsis-induced pulmonary fibrosis

Introduction: The increasing mortality in patients with sepsis-induced pulmonary fibrosis owes to a lack of effective treatment options. This study aims to explore the possibility and possible targets of Reduning in the prevention of sepsis-related pulmonary fibrosis. Methods: The active components and targets of Reduning were searched and screened from the database and analysis platform of traditional Chinese medicine (TCM) system pharmacology. GeneCards, human genome database, DisGeNET database, and the OMIM database were checked to determine the targets associated with sepsis-induced pulmonary fibrosis. DAVID Bioinformatics Resources 6.8 was used for GO and KEGG enrichment analysis to predict its possible signaling pathways and explore its molecular mechanism. The protein-protein interaction (PPI) network was used to identify key active components and core targets. Molecular docking technology was applied to screen the complexes with stable binding of key active components and core targets. Molecular dynamics simulations were used to verify the binding stability and molecular dynamics characteristics of the complexes. The protective effect of RDN on sepsis-induced pulmonary fibrosis was verified by in vitro and in vivo experiments. Results: There were 319 shared targets between sepsis-induced pulmonary fibrosis and RDN. GO enrichment analysis showed that they mainly regulated and participated in the positive regulation of kinase activity, mitogen-activated protein kinase (MAPK) cascade, and protein phosphorylation. KEGG enrichment analysis showed that they were mainly enriched in the mitogen-activated protein kinase cascade signaling pathway, the calcium signaling pathway, the apoptosis pathway, and other signaling pathways. The results of molecular docking and molecular dynamics simulations showed that the active components, stigmasterol, beta-sitosterol, and quercetin, had good binding activities with ERBB2, and they exhibited good stability. Molecular validation experiments confirmed RDN could alleviate lung fibrosis induced by cecum ligation and puncture (CLP), in parallel with the inhibition of the ERBB2-p38 MAPK pathway in mouse alveolar macrophages (AMs). Discussion: Reduning may prevent sepsis-induced pulmonary fibrosis by regulating the ERBB2-p38 MAPK signaling pathway, which provides a possibility for the prevention of sepsis-induced pulmonary fibrosis with traditional Chinese medicine.

TGF-beta signal transduction: biology, function and therapy for diseases

The transforming growth factor beta (TGF-β) is a crucial cytokine that get increasing concern in recent years to treat human diseases. This signal controls multiple cellular responses during embryonic development and tissue homeostasis through canonical and/or noncanonical signaling pathways. Dysregulated TGF-β signal plays an essential role in contributing to fibrosis via promoting the extracellular matrix deposition, and tumor progression via inducing the epithelial-to-mesenchymal transition, immunosuppression, and neovascularization at the advanced stage of cancer. Besides, the dysregulation of TGF-beta signal also involves in other human diseases including anemia, inflammatory disease, wound healing and cardiovascular disease et al. Therefore, this signal is proposed to be a promising therapeutic target in these diseases. Recently, multiple strategies targeting TGF-β signals including neutralizing antibodies, ligand traps, small-molecule receptor kinase inhibitors targeting ligand-receptor signaling pathways, antisense oligonucleotides to disrupt the production of TGF-β at the transcriptional level, and vaccine are under evaluation of safety and efficacy for the forementioned diseases in clinical trials. Here, in this review, we firstly summarized the biology and function of TGF-β in physiological and pathological conditions, elaborated TGF-β associated signal transduction. And then, we analyzed the current advances in preclinical studies and clinical strategies targeting TGF-β signal transduction to treat diseases.

Beyond cardiomyocytes: Cellular diversity in the heart's response to exercise

Cardiomyocytes comprise ∼70% to 85% of the total volume of the adult mammalian heart but only about 25% to 35% of its total number of cells. Advances in single cell and single nuclei RNA sequencing have greatly facilitated investigation into and increased appreciation of the potential functions of non-cardiomyocytes in the heart. While much of this work has focused on the relationship between non-cardiomyocytes, disease, and the heart's response to pathological stress, it will also be important to understand the roles that these cells play in the healthy heart, cardiac homeostasis, and the response to physiological stress such as exercise. The present review summarizes recent research highlighting dynamic changes in non-cardiomyocytes in response to the physiological stress of exercise. Of particular interest are changes in fibrotic pathways, the cardiac vasculature, and immune or inflammatory cells. In many instances, limited data are available about how specific lineages change in response to exercise or whether the changes observed are functionally important, underscoring the need for further research.