Cardiac fibroblasts regulate the development of heart failure via Htra3-TGF-β-IGFBP7 axis

IGFBP7: A novel biomarker involved in a positive feedback loop with TGF-β1 in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease characterized by irreversible scarring of the lungs, predominantly affecting older adults. The limited therapeutic options available are largely due to an insufficient understanding of IPF etiology and pathogenesis. This study investigated potential biomarkers to enhance IPF diagnosis and treatment strategies. Through single-cell RNA sequencing (scRNA-seq) and bulk RNA sequencing analyses of public datasets, four hub genes-FTH1, FABP5, DCXR, and IGFBP7-were identified as strongly associated with IPF. Subsequent validation in in vivo and in vitro models confirmed IGFBP7 as a novel biomarker. Double immunofluorescence staining and scRNA-seq analysis revealed that IGFBP7 expression is elevated in IPF epithelial cells. IGFBP7 shows potential for early diagnosis of IPF and can differentiate IPF from other diseases. Gene set enrichment analysis revealed the involvement of IGFBP7 in IPF pathogenesis, particularly through its strong connection to the TGF-β signaling pathway, which drives inflammation and fibrosis. In vitro studies with the TGF-β inhibitor SB431542 showed that inhibition of the TGF-β pathway significantly reduced IGFBP7 expression. Furthermore, IGFBP7 knockdown decreased the expression of markers associated with epithelial-mesenchymal transition and fibrosis while suppressing TGF-β1 expression. These results suggest that IGFBP7 forms a positive feedback loop with TGF-β1. In conclusion, this research identified IGFBP7 as a promising biomarker with significant diagnostic and therapeutic potential for IPF. These insights pave the way for improved diagnostics and the development of targeted antifibrosis therapies, while deepening our understanding of IPF mechanisms.

Cellular senescence as a key player in chronic heart failure pathogenesis: Unraveling mechanisms and therapeutic opportunities

Chronic heart failure (CHF) is the final stage of heart disease and is caused by various factors. Unfortunately, CHF has a poor prognosis and a high mortality rate. Recent studies have found that aging is a significant risk factor for the development of CHF and that cellular senescence plays a vital role in its development. This article reviews different types of cellular senescence, mitochondrial dysfunction in senescent cells, autophagy in senescent cells, and senescence-associated secretory phenotype (SASP), and epigenetic regulation, to provide new perspectives on the research and treatment of CHF.

Scar-associated macrophages and biliary epithelial cells interaction exacerbates hepatic fibrosis in biliary atresia

BACKGROUND

Biliary atresia (BA) is a severe pediatric biliary disorder characterized by the progressive obstruction of liver bile ducts. In the absence of treatment, fibrosis advances rapidly in most affected children. Despite the identification of various factors contributing to fibrosis progression, comprehensive investigations into the microenvironmental alterations within the liver are still scarce.

METHODS

Single-cell RNA sequencing (scRNA-seq) was conducted on two normal tissues adjacent to liver tumors, two choledochal cyst liver tissues, and four BA liver tissues. This analysis, combined with spatial localization data, elucidated the heterogeneity of the livers affected by BA. Ultimately, a diagnostic model for BA was developed, leveraging high-resolution fibrosis-related gene signatures.

RESULTS

We identified scar-associated macrophages (SAMs) originating from monocytes, which played a pivotal role in fibrosis progression and may be implicated in the epithelial-mesenchymal transition (EMT) of biliary epithelial cells (BECs). Furthermore, the hub genes CD96, EVL, S100A6, and S100A11 were found to be upregulated in SAMs and regulatory T cells (Tregs), aiding in the diagnosis of BA.

CONCLUSION

SAMs and BECs not only exhibited a pro-fibrotic phenotype but also co-localized within fibrotic regions. Their interaction may facilitate the activation of EMT, highlighting a potential therapeutic target for BA treatment.

IMPACT

Analysis of the immune landscape: Through single-cell and spatial transcriptomic techniques, the paper reveals the complex immune landscape associated with BA fibrosis. Exploration of new therapeutic targets: This paper reveals that SAMs can promote the progression of liver fibrosis by regulating the EMT conversion of BECs, opening up a new therapeutic approach. Application of diagnostic markers: The paper identifies biomarkers that may improve early diagnostic accuracy and postoperative prognosis and recommends their incorporation into clinical practice.

Renal tubular epithelial IGFBP7 interacts with PKM2 to drive renal lipid accumulation and fibrosis

Renal fibrosis serves as a critical pathological mechanism driving the progression of chronic kidney disease (CKD). However, the pathogenesis and therapeutic targets involved in this process remain unclear. Interestingly, we currently found that IGFBP7 is highly expressed in tubular epithelial cells (TECs) from the fibrotic kidneys of human patients and animal models. However, their functional roles in abnormal kidney repair and renal fibrosis remain unclear. Here, we report that IGFBP7 knockout (KO) or TEC conditional KO (cKO) attenuated renal fibrosis in multiple mouse models, whereas IGFBP7 knock-in or restoration in IGFBP7-KO mice enhanced renal fibrosis. These in vivo findings were verified using cultured TECs and organoids generated from IGFBP7-cKO mice. Mechanistically, we found that IGFBP7 bound to pyruvate kinase M2 (PKM2) to promote the acetylation of PKM2 at the K433 site, thereby enhancing PKM2 dimerization and nuclear translocation, and subsequently accelerating lipid production and renal fibrosis via SREBP1-dependent mechanisms. Notably, through drug screening, we identified salmeterol (an asthma medication) as an IGFBP7 antagonist that effectively reduced fibrosis. Our findings reveal the IGFBP7/PKM2/SREBP1 axis as a central regulator of lipogenic fibrosis, offering genetic and pharmacological inhibition of IGFBP7 as promising therapeutic strategies for CKD.

Selective inhibition of stromal mechanosensing suppresses cardiac fibrosis

Matrix-derived biophysical cues are known to regulate the activation of fibroblasts and their subsequent transdifferentiation into myofibroblasts1-6, but whether modulation of these signals can suppress fibrosis in intact tissues remains unclear, particularly in the cardiovascular system7-10. Here we demonstrate across multiple scales that inhibition of matrix mechanosensing in persistently activated cardiac fibroblasts potentiates-in concert with soluble regulators of the TGFβ pathway-a robust transcriptomic, morphological and metabolic shift towards quiescence. By conducting a meta-analysis of public human and mouse single-cell sequencing datasets, we identify the focal-adhesion-associated tyrosine kinase SRC as a fibroblast-enriched mechanosensor that can be targeted selectively in stromal cells to mimic the effects of matrix softening in vivo. Pharmacological inhibition of SRC by saracatinib, coupled with TGFβ suppression, induces synergistic repression of key profibrotic gene programs in fibroblasts, characterized by a marked inhibition of the MRTF-SRF pathway, which is not seen after treatment with either drug alone. Importantly, the dual treatment alleviates contractile dysfunction in fibrotic engineered heart tissues and in a mouse model of heart failure. Our findings point to joint inhibition of SRC-mediated stromal mechanosensing and TGFβ signalling as a potential mechanotherapeutic strategy for treating cardiovascular fibrosis.

Modeling diabetic cardiomyopathy using human cardiac organoids: Effects of high glucose and lipid conditions

Diabetic cardiomyopathy (DCM) is a complex metabolic disorder resulting from chronic hyperglycemia and lipid toxicity, which leads to cardiac dysfunction, fibrosis, inflammation, and mitochondrial impairment. Traditional two-dimensional (2D) cell cultures and animal models have limitations in replicating human cardiac physiology and pathophysiology. In this study, we successfully developed a three-dimensional (3D) model of DCM using cardiac organoids generated from human induced pluripotent stem cells (hiPSCs). These organoids were treated with varying concentrations of glucose and sodium palmitate to mimic the high-glucose and high-lipid environment associated with diabetes. At lower concentrations, glucose and sodium palmitate enhanced cell viability, while higher concentrations induced significant cardiotoxic effects, including apoptosis, oxidative stress, and mitochondrial dysfunction. The cardiac organoids also exhibited increased expression of cardiac injury markers, fibrosis-related genes, and inflammatory cytokines under high-glucose and high-lipid conditions. Treatment with metformin, a widely used antidiabetic drug, mitigated these adverse effects, indicating the model's potential for drug testing and evaluation. Our findings demonstrate that this human-derived 3D cardiac organoid model provides a more physiologically relevant platform for studying DCM and can effectively complement traditional models. This model holds promise for advancing the understanding of diabetic heart disease and for assessing the efficacy of potential therapeutic interventions.

Construction of a deep learning model and identification of the pivotal characteristics of FGF7- and MGST1- positive fibroblasts in heart failure post-myocardial infarction

Dysregulation of fibroblast function is closely associated with the occurrence of heart failure after myocardial infarction (post-MI HF). Myocardial fibrosis is a detrimental consequence of aberrant fibroblast activation and extracellular matrix deposition following myocardial infarction (MI). However, the heterogeneity of fibroblasts in normal cardiac tissue and heart failure tissue remains to be further investigated. We discovered that the abundance of FGF7+MGST1+ fibroblasts were down-regulated in post-MI HF according to scRNA-seq analysis. Key gene characteristics of FGF7+MGST1+ fibroblasts were uncovered through both differential expression analysis and hdWGCNA pipeline. Pseudotime analysis revealed that FGF7+MGST1+ fibroblasts were gradually decreased with the occurrence of heart failure. Cell-cell communication analysis indicated an enhanced secretory ability in FGF7+MGST1+ fibroblasts compared to other fibroblasts. Utilizing machine learning algorithms, we identified 17 feature genes of this cell population. A deep learning model capable of predicting heart failure was successfully built based on these feature genes and immune infiltration levels of post-MI HF. FGF7 was highly related to cardioprotective pathway terms, including "PI3K/AKT pathway" and "protein secretion". Parallelly, mendelian randomization analysis was adopted to better understand the causal relationships between feature genes and post-MI HF. Results indicated that MGST1 was causally associated with heart failure, consistent with single cell data. And the post-MI HF mouse model was constructed and qRT-PCR assays supported that both FGF7 and MGST1 were largely down-regulated in myocardial infarction area than other cardiac tissues. These findings provide new insights into the roles of FGF7+MGST1+ fibroblasts in post MI HF.

Proteome Alterations in Cardiac Fibroblasts: Insights from Experimental Myocardial Infarction and Clinical Ischaemic Cardiomyopathy

Ischaemic heart disease (IHD) is a chronic condition that can cause pathological cardiac remodelling and heart failure (HF). In this study, we sought to determine how cardiac fibroblasts were altered post-experimental myocardial infarction (MI). Female C57BL6 mice underwent experimental MI by permanent left coronary artery ligation. Cardiac fibroblasts were isolated from extracted heart tissue of experimental MI mice and subsequently treated with the pro-fibrotic cytokine, TGF-β, for 24 h and analysed using high throughput LC-MS/MS analysis. Findings were validated using mass spectrometry data generated from human left ventricular tissue analysis, which were collected from patients with ischaemic cardiomyopathy (ISCM) and age/sex-matched patients without clinical HF (NF). Proteomic analysis revealed significant protein expression changes in mouse cardiac fibroblasts after MI. These changes were most pronounced at 1 month post-MI, compared to earlier time points (3 days and 1 week). TGF-β treatment profoundly affected fibroblast cells extracted from MI mice, indicating a heightened sensitivity to pro-fibrotic factors after myocardial injury. Extracellular matrix (ECM) proteins significantly altered in MI fibroblasts following TGF-β treatment were significantly associated with cardiac remodelling. Notably, Lox was significantly changed in both isolated fibroblasts treated with TGF-β from experiment MI mice and human ISCM. Isolated cardiac fibroblasts from MI mice are more susceptible to developing pathogenic traits following TGF-β treatment than isolated fibroblasts from normal heart tissue. ECM proteins associated with these enhanced fibroblast activities and functions are evident. These altered proteins may play a functional role in MI-associated cardiac dysfunction.

Cardiac protection of wogonin in mice with pulmonary fibrosis by regulating Sirt1/ γ-H2AX pathway

Background

Clinical evidence suggests that pulmonary fibrosis (PF) and heart failure (HF) often co-exist; however, the specific impact of PF on HF remains underexplored. This gap in understanding complicates the management and treatment of HF in patients with PF.

Objectives

To investigate the effects of PF on cardiac function and myocardial fibrosis using a mouse PF model and evaluate the therapeutic potential of wogonin, a flavonoid compound known for its anti-PF properties.

Methods

A PF mouse model was established via intratracheal administration of bleomycin (BLM). Starting on day 8 post-BLM treatment, wogonin (50 mg/kg) was intraperitoneally administered every 2 days for 2 weeks. Cardiac function was assessed using echocardiography, while myocardial fibrosis was evaluated through Masson staining. In vitro, H9C2 cardiomyocytes were exposed to CoCl2 or H2O2 for 24 h with or without wogonin (20 μM) treatment. Apoptosis and DNA damage markers were analysed using immunofluorescence, immunoblotting, and the Comet assay. The interaction between wogonin and Sirt1 was examined using biotin-affinity pulldown assays and molecular docking simulations.

Results

Mice with PF exhibited significant cardiac dysfunction and myocardial fibrosis. Wogonin treatment markedly improved ejection fraction and attenuated myocardial fibrosis in PF mice. Mechanistic studies revealed that wogonin alleviated DNA damage and cardiomyocyte apoptosis by upregulating Sirt1 and downregulating γ-H2AX expression. Docking simulations predicted that wogonin forms a stable complex with Sirt1 through hydrogen-bonding and hydrophobic interactions, which was further validated by biotin-affinity pulldown assays.

Conclusion

Wogonin exerts protective effects against cardiac dysfunction and fibrosis in PF mice by modulating Sirt1/γ-H2AX-mediated pathways to reduce DNA damage and apoptosis. These findings suggest the potential of wogonin as a therapeutic agent for managing HF associated with PF.

Spatial genomics: Mapping the landscape of fibrosis

Organ fibrosis causes major morbidity and mortality worldwide. Treatments for fibrosis are limited, with organ transplantation being the only cure. Here, we review how various state-of-the-art spatial genomics approaches are being deployed to interrogate fibrosis across multiple organs, providing exciting insights into fibrotic disease pathogenesis. These include the detailed topographical annotation of pathogenic cell populations and states, detection of transcriptomic perturbations in morphologically normal tissue, characterization of fibrotic and homeostatic niches and their cellular constituents, and in situ interrogation of ligand-receptor interactions within these microenvironments. Together, these powerful readouts enable detailed analysis of fibrosis evolution across time and space.

Decoding the regulatory roles of circular RNAs in cardiac fibrosis

Cardiovascular diseases (CVDs) are the primary cause of death globally. The evolution of nearly all types of CVDs is characterized by a common theme: the emergence of cardiac fibrosis. The precise mechanisms that trigger cardiac fibrosis are still not completely understood. In recent years, a type of non-coding regulatory RNA molecule known as circular RNAs (circRNAs) has been reported. These molecules are produced during back splicing and possess significant biological capabilities, such as regulating microRNA activity, serving as protein scaffolds and recruiters, competing with mRNA, forming circR-loop structures to modulate transcription, and translating polypeptides. Furthermore, circRNAs exhibit a substantial abundance, notable stability, and specificity of tissues, cells, and time, endowing them with the potential as biomarkers, therapeutic targets, and therapeutic agents. CircRNAs have garnered growing interest in the field of CVDs. Recent investigations into the involvement of circRNAs in cardiac fibrosis have yielded encouraging findings. This study aims to provide a concise overview of the existing knowledge about the regulatory roles of circRNAs in cardiac fibrosis.

Cardiac Fibrosis in the Multi-Omics Era: Implications for Heart Failure

Cardiac fibrosis, a hallmark of heart failure and various cardiomyopathies, represents a complex pathological process that has long challenged therapeutic intervention. High-throughput omics technologies have begun revolutionizing our understanding of the molecular mechanisms driving cardiac fibrosis and are providing unprecedented insights into its heterogeneity and progression. This review provides a comprehensive analysis of how techniques-encompassing genomics, epigenomics, transcriptomics, proteomics, and metabolomics-are providing insight into our understanding of cardiac fibrosis. Genomic studies have identified novel genetic variants and regulatory networks associated with fibrosis susceptibility and progression, and single-cell transcriptomics has unveiled distinct cardiac fibroblast subpopulations with unique molecular signatures. Epigenomic profiling has revealed dynamic chromatin modifications controlling fibroblast activation states, and proteomic analyses have identified novel biomarkers and potential therapeutic targets. Metabolomic studies have uncovered important alterations in cardiac energetics and substrate utilization during fibrotic remodeling. The integration of these multi-omic data sets has led to the identification of previously unrecognized pathogenic mechanisms and potential therapeutic targets, including cell-type-specific interventions and metabolic modulators. We discuss how these advances are driving the development of precision medicine approaches for cardiac fibrosis while highlighting current challenges and future directions in translating multi-omic insights into effective therapeutic strategies. This review provides a systems-level perspective on cardiac fibrosis that may inform the development of more effective, personalized therapeutic approaches for heart failure and related cardiovascular diseases.

Whole tissue proteomic analyses of cardiac ATTR and AL unveil mechanisms of tissue damage

BACKGROUND

Cardiac AL and ATTR are potentially fatal cardiomyopathies. Current therapies do not address mechanisms of tissue dysfunction because these remain unknown. Our prior work focused on the amyloid plaque proteome, which may not capture tissue-wide proteomic alterations.

OBJECTIVES

To evaluate mechanisms of tissue dysfunction in cardiac AL and ATTR using a full biopsy tissue proteomics approach.

METHODS

We performed proteomics analysis on 76 ATTR and 27 AL diagnostic endomyocardial biopsies.

RESULTS

Stage-3 AL patients exhibited increased coagulation, extracellular matrix remodelling (ECM), epithelial-to-mesenchymal transition (EMT), complement activation, hypoxia, and clathrin-mediated endocytosis pathways vs. stages-1/2, with decreased healthy cardiac metabolism. In stages-2 and 3 ATTR, immunoglobulin proteins, complement, and keratinisation pathways were increased compared to stage-1. Unsupervised analyses identified an ATTR group with worse survival characterised by upregulated complement and downregulated metabolic pathways. Compared to ATTR, AL had higher clathrin-mediated endocytosis, mRNA splicing, and ribosomal proteins, while ATTR had higher complement levels.

CONCLUSIONS

This study identifies known processes dysregulated in heart failure with preserved ejection fraction as well as novel pathways responsible for tissue damage. Our results support an immune-mediated mechanism of tissue toxicity in cardiac amyloidosis, especially among patients with worse outcomes.

Shared molecular, cellular, and environmental hallmarks in cardiovascular disease and cancer: Any place for drug repurposing?

Cancer and cardiovascular disease (CVD) are the 2 biggest killers worldwide. Specific treatments have been developed for the 2 diseases. However, mutual therapeutic targets should be considered because of the overlap of cellular and molecular mechanisms. Cancer research has grown at a fast pace, leading to an increasing number of new mechanistic treatments. Some of these drugs could prove useful for treating CVD, which realizes the concept of cancer drug repurposing. This review provides a comprehensive outline of the shared hallmarks of cancer and CVD, primarily ischemic heart disease and heart failure. We focus on chronic inflammation, altered immune response, stromal and vascular cell activation, and underlying signaling pathways causing pathological tissue remodeling. There is an obvious scope for targeting those shared mechanisms, thereby achieving reciprocal preventive and therapeutic benefits. Major attention is devoted to illustrating the logic, advantages, challenges, and viable examples of drug repurposing and discussing the potential influence of sex, gender, age, and ethnicity in realizing this approach. Artificial intelligence will help to refine the personalized application of drug repurposing for patients with CVD. SIGNIFICANCE STATEMENT: Cancer and cardiovascular disease (CVD), the 2 biggest killers worldwide, share several underlying cellular and molecular mechanisms. So far, specific therapies have been developed to tackle the 2 diseases. However, the development of new cardiovascular drugs has been slow compared with cancer drugs. Understanding the intersection between pathological mechanisms of the 2 diseases provides the basis for repurposing cancer therapeutics for CVD treatment. This approach could allow the rapid development of new drugs for patients with CVDs.

Complex regulation of cardiac fibrosis: insights from immune cells and signaling pathways

Cardiac fibrosis is a physiological process that involves the formation of scar tissue in the heart in response to injury or damage. This process is initially a protective measure characterized by enhanced fibroblasts, which are responsible for producing extracellular matrix proteins that provide structural support to the heart. However, when fibrosis becomes excessive, it can lead to adverse outcomes, including increasing tissue stiffness and impaired cardiac function, which can ultimately result in heart failure with a poor prognosis. While fibroblasts are the primary cells involved in cardiac fibrosis, immune cells have also been found to play a vital role in its progression. Recent research has shown that immune cells exert multifaceted effects besides regulation of inflammatory response. Advanced research techniques such as single-cell sequencing and multiomics have provided insights into the specific subsets of immune cells involved in fibrosis and the complex regulation of the process. Targeted immunotherapy against fibrosis is gaining traction as a potential treatment option, but it is still unclear how immune cells achieve this regulation and whether distinct subsets are involved in different roles. To better understand the role of immune cells in cardiac fibrosis, it is essential to examine the classical signaling pathways that are closely related to fibrosis formation. We have also focused on the unique properties of diverse immune cells in cardiac fibrosis and their specific intercommunications. Therefore, this review will delve into the plasticity and heterogeneity of immune cells and their specific roles in cardiac fibrosis, which propose insights to facilitate the development of anti-fibrosis therapeutic strategies.

Applications of Single-Cell Omics Technologies for Induced Pluripotent Stem Cell-Based Cardiovascular Research

Single-cell omics technologies have transformed our investigation of genomic, transcriptomic, and proteomic landscapes at the individual cell level. In particular, the application of single-cell RNA sequencing has unveiled the complex transcriptional variations inherent in cardiac cells, offering valuable perspectives into their dynamics. This review focuses on the integration of single-cell omics with induced pluripotent stem cells (iPSCs) in the context of cardiovascular research, offering a unique avenue to deepen our understanding of cardiac biology. By synthesizing insights from various single-cell technologies, we aim to elucidate the molecular intricacies of heart health and diseases. Beyond current methodologies, we explore the potential of emerging paradigms such as single-cell/spatial omics, delving into their capacity to reveal the spatial organization of cellular components within cardiac tissues. Furthermore, we anticipate their transformative role in shaping the future of cardiovascular research. This review aims to contribute to the advancement of knowledge in the field, offering a comprehensive perspective on the synergistic potential of transcriptomic analyses, iPSC applications, and the evolving frontier of spatial omics.

Cardiac Reprogramming and Gata4 Overexpression Reduce Fibrosis and Improve Diastolic Dysfunction in Heart Failure With Preserved Ejection Fraction

BACKGROUND

Heart failure with preserved ejection fraction (HFpEF) is a major health concern. Pathological stimuli and interactions between cardiac fibroblasts (CFs) and other cell types may lead to cardiac fibrosis and diastolic dysfunction, which are hallmarks of HFpEF. Interstitial and perivascular cardiac fibrosis correlates with poor prognosis in HFpEF; however, mechanisms of fibrosis remain poorly elucidated, and targeted therapies are lacking. Cardiac reprogramming is a promising therapeutic approach for myocardial infarction that facilitates cardiac regeneration and antifibrosis action through Mef2c/Gata4/Tbx5/Hand2 (MGTH) overexpression in resident CFs. However, the efficacy of this approach on HFpEF is yet to be established.

METHODS

Herein, we examined the effects of cardiac reprogramming in HFpEF using Tcf21iCre/Tomato/MGTH2A transgenic mice, which expressed both MGTH and reporter expression in CFs for cardiac reprogramming and lineage tracing upon tamoxifen administration. To establish HFpEF model mice, we used a combination of a high-fat diet and nitric oxide synthase inhibition. Bulk RNA-sequencing, single-cell RNA-sequencing, and spatial transcriptomics were conducted to determine fibrotic mechanisms and the efficacy of cardiac reprogramming in HFpEF. We generated new tamoxifen-inducible transgenic mice overexpressing each reprogramming factor in CFs to investigate the effect of single factors. Last, we analyzed the effect of reprogramming factors in human CFs.

RESULTS

Cardiac reprogramming with MGTH overexpression improved diastolic dysfunction, cardiac hypertrophy, fibrosis, inflammation, and capillary loss in HFpEF. Cardiac reprogramming converted approximately 1% of resident CFs into induced cardiomyocytes. Bulk RNA-seq indicated that MGTH overexpression upregulated genes related to heart contraction and suppressed the fetal gene program (Nppa and Nppb) and proinflammatory and fibrotic signatures. Single-cell RNA-sequencing and spatial transcriptomics revealed that multiple CF clusters upregulated fibrotic genes to induce diffuse interstitial fibrosis, whereas distinct CF clusters generated focal perivascular fibrosis in HFpEF. MGTH overexpression reversed these profibrotic changes. Among 4 reprogramming factors, only Gata4 overexpression in CFs reduced fibrosis and improved diastolic dysfunction in HFpEF by suppressing CF activation without generating new induced cardiomyocytes. Gata4 overexpression also suppressed profibrotic signatures in human CFs.

CONCLUSIONS

Overexpressing Gata4 in CFs may be a promising therapeutic approach for HFpEF by suppressing fibrosis and improving diastolic dysfunction.

Left superior cervical ganglia lymph node mimicry and its role in rat ventricular arrhythmias following myocardial infarction

AIM

Sympathetic overactivation may lead to severe ventricular arrhythmias (VAs) post-myocardial infarction (MI). The superior cervical ganglion (SCG) is an extracardiac sympathetic ganglion which regulates cardiac autonomic tone. We aimed to investigate the characteristics and functional significance of SCG on neuro-cardiac communication post-MI.

METHODS

Constructed MI rat model by left anterior descending coronary artery ligation, and electrophysiological, SCG sympathetic nerve activity testing, echocardiography and histology study were performed. The proteins and gene expression were detected using RNA-seq, spatial transcriptomics, quantitative PCR, and western blotting.

RESULTS

The SCG neuronal remodeling was recognized by significant increase in adrenergic tyrosine hydroxylase (TH) (+) neurons and decrease in neuronal size. Top differentially expressed genes enriched in pro-inflammatory profile and nerve regulatory factor in left SCG (LSCG) post-MI. Interleukin (IL)-1β and IL-6 increased significantly at Day 3, ahead of nerve growth factor (NGF) which peaked at Day 7 post-MI. Spatial transcriptomics further identified the relativity of TH enrichment with macrophages and cytokines. Therapeutic LSCG-ectomy successfully triggered cardiac denervation and improved VA vulnerability. Eventually, cardiac denervation attenuated macrophage/mast cell infiltration at para-infarct regions, thus improved cardiac dysfunction. Mechanism study revealed that genetic knockdown of NGF receptor trkA in LSCG reversed sympathetic remodeling and cardiac inflammation, which may be partially mediated by substance P and calcitonin gene-related peptide (CGRP).

CONCLUSION

Extracardiac sympathetic LSCG remodeling participated in arrhythmogenesis and cardiac inflammation/function post-MI. NGF bridged neuro-immune crosstalk between pro-inflammatory shifting and sympathetic overdrive. Targeting LSCG modification facilitated cardiac protection and prevented VAs post-MI.

Qifu yixin prescription ameliorates cardiac fibrosis by activating soluble guanylate cyclase (sGC) in heart failure

ETHNOPHARMACOLOGICAL RELEVANCE

Qifu yixin prescription (QYP), an effective traditional Chinese medicine formula, has been utilized in the clinical treatment of cardiovascular diseases for over two decades and has been granted a national invention patent in China. It has demonstrated the ability to improve clinical symptoms in patients with heart failure. However, its precise effects and underlying molecular mechanisms remain unclear.

AIM OF THE STUDY

To evaluate the efficacy of QYP in treating HF and the underlying mechanisms.

MATERIALS AND METHODS

The heart failure (HF) model in mice was established using transverse aortic constriction (TAC), while neonatal rat cardiac fibroblasts (CFs) were utilized for in vitro experiments. The bioactive compounds in QYP were identified through high-performance liquid chromatography (HPLC). Cardiac hypertrophy, function, and fibrosis were assessed using morphological observations, echocardiography, and histomorphometric analyses. To investigate the underlying mechanisms by which QYP alleviates HF, transcriptomic analysis was conducted, and network pharmacology was employed to explore its potential mechanisms of action. Mechanistically, the expression levels of sGC, PKG, ERK, and p-ERK were analyzed using western blotting, immunohistochemistry, and immunofluorescence. Molecular docking was conducted to assess the binding affinity of the compounds of QYP to sGC. Additionally, the effects of QYP on CFs were investigated through cell-based assays.

RESULTS

We identified 33 bioactive compounds in QYP. Histomorphometric and transcriptomic analyses indicated that QYP alleviates cardiac fibrosis in HF. Network pharmacological analysis suggested that the sGC/cGMP/PKG and MAPK pathways are key mechanisms underlying the effects of QYP on cardiac fibrosis. The findings confirmed that QYP activates sGC, leading to the inhibition of ERK phosphorylation. Molecular docking revealed that the compounds of QYP exhibit strong binding affinity to sGC. Additionally, cell-based experiments demonstrated that QYP effectively suppresses CFs activation by stimulating sGC.

CONCLUSIONS

These results indicate QYP improves cardiac fibrosis in HF by activating sGC to inhibit ERK phosphorylation. We propose that QYP is a potential treatment for HF with anti-fibrotic properties.

Single-Cell Sequencing Reveals PD-L1-Mediated Immune Escape Signaling in Lung Adenocarcinoma

Background: Lung cancer has the highest mortality rate among all cancers, for which immunotherapy can frequently lead to drug resistance. To understand the molecular mechanisms behind immune escape in patients with lung cancer and develop predictive and therapeutic targets, we carried out analytical experiments using single-cell sequencing. Methods: We collected eight tumor tissue samples from eight patients with lung adenocarcinoma and categorized them based on the positive reactions for programmed cell death ligand 1 (PD-L1) expression levels. Single-cell sequencing analysis was employed to create a comprehensive cellular landscape. Uniform Manifold Approximation and Projection was used to show the proportion of immune and endothelial cells, along with a map depicting the distribution of different cell types. Cells were subdivided according to molecular markers; the subpopulations were grouped based on PD-L1 levels and tumor marker-positive reactions. The correlation between the occurrence of the PD-L1 reaction and the response time of immune cells was explored; differential gene expression between the groups was elucidated. Finally, quantitative polymerase chain reaction (qPCR) was used to examine the relationship between key differentially expressed genes and PD-L1 immune escape checkpoint response. Results: A total of 58,810 single cells were analyzed, identifying seven distinct cell types. In the PD-L1-positive sample group, B cells, astrocytes, endothelial cells, outer skin cells, and tissue stem cells were present in higher proportions, whereas T and dendritic cells were the main cells in the PD-L1-negative sample group. According to the molecular markers, the seven cell types were divided into 17 cell clusters, with one cluster classified as tumor cells, showing PD-L1 positivity. Eleven molecular markers with different expression levels were simultaneously screened (NAPSA, MUC1, WFDC2, MYO6, LYZ, IGHG4, IGLL5, IGHM, IGKC, AQP3, and IGFBP7), and their association with the PD-L1/PD-1 immune escape axis response was confirmed by qPCR. Conclusion: Our study suggests that PD-L1-mediated immune escape may occur at a later stage of tumor progression, involving both PD-L1-positive and negative immune cells. Additionally, we identified 11 differentially expressed genes that could provide insights into the potential mechanisms of immune escape in patients with lung cancer. These findings offer promising molecular targets for the detection and treatment of immune escape in clinical settings.

Transient Receptor Potential Canonical Channels in Cardiovascular Pathology and Their Modulators

ABSTRACT

Ion channels play a crucial role in various aspects of cardiac function, such as regulating rhythm and contractility. As a result, they serve as key targets for therapeutic interventions in cardiovascular diseases. Cell function is substantially influenced by the concentration of free cytosolic calcium (Ca 2+ ) and the voltage across the plasma membrane. These characteristics are known to be regulated by Ca 2+ -permeable nonselective cationic channels, although our knowledge of these channels is still inadequate. The transient receptor potential (TRP) superfamily comprises of many nonselective cation channels with diverse Ca 2+ permeability. Canonical or classical TRP (TRPC) channels are a subgroup of the TRP superfamily that are expressed ubiquitously in mammalian cells. TRPC channels are multidimensional signaling protein complexes that play essential roles in a variety of physiological and pathological processes in humans, including cancer, neurological disorders, cardiovascular diseases, and others. The objective of this article was to focus on the role that TRPC channels play in the cardiovascular system. The role of TRPC channels will be deeply discussed in cardiovascular pathology. Together, a critical element in developing novel treatments that target TRPC channels is comprehending the molecular mechanisms and regulatory pathways of TRPC channels in related cardiovascular diseases and conditions.

Persistent hypertension induces atrial remodeling and atrial fibrillation through DNA damage and ATM/CHK2/p53 signaling pathway

Atrial fibrillation (AF) is the most prevalent arrhythmia in clinical practice, with hypertension emerging as an independent risk factor. Previous literature has established associations between DNA damage response (DDR) and autophagy in relation to the pathogenesis of AF. The aim of this study was to evaluate the effect of atrial DNA damage response in persistent hypertension-induced atrial electrical and structural remodeling, and to further explore the potential therapeutic targets. Patient samples, spontaneous hypertensive rats (SHR) and angiotensin II (Ang II)-challenged HL-1 cells were employed to elucidate the detailed mechanisms. Bioinformatics analysis and investigation on human atrial samples revealed a critical role of DDR in the pathogenesis of AF. The markers of atrial DNA damage, DDR, autophagy, inflammation and fibrosis were detected by western blot, immunofluorescence, monodansyl cadaverine (MDC) assay and transmission electron microscopy. Compared with the control group, SHR exhibited significant atrial electrical and structural remodeling, abnormal increase of autophagy, inflammation, and fibrosis, which was accompanied by excessive activation of DDR mediated by the ATM/CHK2/p53 pathway. These detrimental changes were validated by in vitro experiments. Ang II-challenged HL-1 cells also exhibited significantly elevated γH2AX expression, and markers related to autophagy, inflammation as well as structural remodeling. Additionally, inhibition of ATM with KU55933 (a specific ATM inhibitor) significantly reversed these effects. Collectively, these data demonstrate that DNA damage and the subsequently overactivated ATM/CHK2/p53 pathway play critical roles in hypertension-induced atrial remodeling and the susceptibility to AF. Targeting ATM/CHK2/p53 signaling may serve as a potential therapeutic strategy against AF.

Remodeling of the extracellular matrix by serine proteases as a prerequisite for cancer initiation and progression

The extracellular matrix (ECM) serves as a physical scaffold for tissues that is composed of structural proteins such as laminins, collagens, proteoglycans and fibronectin, forming a three dimensional network, and a wide variety of other matrix proteins with ECM-remodeling and signaling functions. The activity of ECM-associated signaling proteins is tightly regulated. Thus, the ECM serves as a reservoir for water and growth regulatory signals. The ECM architecture is dynamically modulated by multiple serine proteases that process both structural and signaling proteins to regulate physiological processes such as organogenesis and tissue homeostasis but they also contribute to pathological events, especially cancer progression. Here, we review the current literature regarding the role of ECM remodeling by serine proteases (KLKs, uPA, furin, HtrAs, granzymes, matriptase, hepsin) in tumorigenesis.

Insulin-like growth factor-binding protein 7 exacerbates inflammatory response and lipid metabolism imbalance in alcohol-associated liver disease

Alcohol-associated liver disease(ALD), caused by excessive alcohol consumption, are often associated with inflammatory outbreaks and lipid deposition in the liver. The role of Insulin-like growth factor-binding protein 7 (IGFBP7), an important metabolic regulator, in ALD, its underlying regulatory mechanism, and its potential implication in anti-ALD therapies remain unknown. We investigated the effects of IGFBP7 on hepatic inflammation and lipid metabolism disruption in a mouse model of ALD. Mice were fed by chronic ethanol feeding plus a single binge of ethanol feeding(chronic-plus-single-binge model). In addition, ethanol exposure modeling studies were performed on cultured hepatocytes to verify molecular correlations. The results showed that IGFBP7 expression was significantly elevated in the livers of mice and hepatocytes after chronic ethanol exposure. Subsequently, the results of a study by specific knockout of IGFBP7(IGFBP7-cKO) in mouse hepatocytes and lentiviral silencing of IGFBP7 in vivo suggested that IGFBP7 deletion could improve liver function levels in alcohol-fed mice; It also attenuated the outbreak of hepatitis factor and the disorder of lipid metabolism in mice.Using RNA-seq sequencing of mouse liver tissue, we found that IGFBP7 affects several downstream metabolic signaling pathways, including PPAR, MAPK, FoxO, etc. Then, we used the PPARα plasmid in hepatocytes and discovered that overexpressing PPARα reversed the impact of IGFBP7 on lipid metabolism disorders in hepatocytes. In conclusion, IGFBP7 deficiency in alcohol-associated liver disease alleviates the decline in liver function and the imbalance of lipid metabolism in mice, attenuates the inflammatory outbreak, and affects a variety of downstream lipid metabolism factors by regulating PPARα. Hence, IGFBP7 may be an effective therapeutic target in the treatment of ALD.

Single-cell spatial transcriptomics in cardiovascular development, disease, and medicine

Cardiovascular diseases (CVDs) impose a significant burden worldwide. Despite the elucidation of the etiology and underlying molecular mechanisms of CVDs by numerous studies and recent discovery of effective drugs, their morbidity, disability, and mortality are still high. Therefore, precise risk stratification and effective targeted therapies for CVDs are warranted. Recent improvements in single-cell RNA sequencing and spatial transcriptomics have improved our understanding of the mechanisms and cells involved in cardiovascular phylogeny and CVDs. Single-cell RNA sequencing can facilitate the study of the human heart at remarkably high resolution and cellular and molecular heterogeneity. However, this technique does not provide spatial information, which is essential for understanding homeostasis and disease. Spatial transcriptomics can elucidate intracellular interactions, transcription factor distribution, cell spatial localization, and molecular profiles of mRNA and identify cell populations causing the disease and their underlying mechanisms, including cell crosstalk. Herein, we introduce the main methods of RNA-seq and spatial transcriptomics analysis and highlight the latest advances in cardiovascular research. We conclude that single-cell RNA sequencing interprets disease progression in multiple dimensions, levels, perspectives, and dynamics by combining spatial and temporal characterization of the clinical phenome with multidisciplinary techniques such as spatial transcriptomics. This aligns with the dynamic evolution of CVDs (e.g., "angina-myocardial infarction-heart failure" in coronary artery disease). The study of pathways for disease onset and mechanisms (e.g., age, sex, comorbidities) in different patient subgroups should improve disease diagnosis and risk stratification. This can facilitate precise individualized treatment of CVDs.

Cardiac Aging in the Multi-Omics Era: High-Throughput Sequencing Insights

Cardiovascular diseases are a leading cause of mortality worldwide, and the risks of both developing a disease and receiving a poor prognosis increase with age. With increasing life expectancy, understanding the mechanisms underlying heart aging has become critical. Traditional techniques have supported research into finding the physiological changes and hallmarks of cardiovascular aging, including oxidative stress, disabled macroautophagy, loss of proteostasis, and epigenetic alterations, among others. The advent of high-throughput multi-omics techniques offers new perspectives on the molecular mechanisms and cellular processes in the heart, guiding the development of therapeutic targets. This review explores the contributions and characteristics of these high-throughput techniques to unraveling heart aging. We discuss how different high-throughput omics approaches, both alone and in combination, produce robust and exciting new findings and outline future directions and prospects in studying heart aging in this new era.

Cinnamaldehyde activates AMPK/PGC-1α pathway via targeting GRK2 to ameliorate heart failure

BACKGROUND

According to recent research, treating heart failure (HF) by inhibiting G protein-coupled receptor kinase 2 (GRK2) to improve myocardial energy metabolism has been identified as a potential approach. Cinnamaldehyde (CIN), a phenylpropyl aldehyde compound, has been demonstrated to exhibit beneficial effects in cardiovascular diseases. However, whether CIN inhibits GRK2 to ameliorate myocardial energy metabolism in HF is still unclear.

PURPOSE

This study examines the effects of CIN on GRK2 and myocardial energy metabolism to elucidate its underlying mechanism to treat HF.

METHODS

The isoproterenol (ISO) induced HF model in vivo and in vitro were constructed using Sprague-Dawley (SD) rats and primary neonatal rat cardiomyocytes (NRCMs). Based on this, the effects of CIN on myocardial energy metabolism and GRK2 were investigated. Additionally, validation experiments were conducted after interfering and over-expressing GRK2 in ISO-induced NRCMs to verify the regulatory effect of CIN on GRK2. Furthermore, binding capacity between GRK2 and CIN was explored by Cellular Thermal Shift Assay (CETSA) and Microscale Thermophoresis (MST).

RESULTS

In vivo and in vitro, CIN significantly improved HF as demonstrated by reversing abnormal changes in myocardial injury markers, inhibiting myocardial hypertrophy and decreasing myocardial fibrosis. Additionally, CIN promoted myocardial fatty acid metabolism to ameliorate myocardial energy metabolism disorder by activating AMPK/PGC-1α signaling pathway. Moreover, CIN reversed the inhibition of myocardial fatty acid metabolism and AMPK/PGC-1α signaling pathway by GRK2 over-expression in ISO-induced NRCMs. Meanwhile, CIN had no better impact on the stimulation of cardiac fatty acid metabolism and the AMPK/PGC-1α signaling pathway in ISO-induced NRCMs when GRK2 was disrupted. Noticeably, CETSA and MST confirmed that CIN binds to GRK2 directly. The binding of CIN and GRK2 promoted the ubiquitination degradation of GRK2 mediated by murine double mimute 2.

CONCLUSION

This study demonstrates that CIN exerts a protective intervention in HF by targeting GRK2 and promoting its ubiquitination degradation to activate AMPK/PGC-1α signaling pathway, ultimately improving myocardial fatty acid metabolism.

m6A modification in non-coding RNAs: Mechanisms and potential therapeutic implications in fibrosis

N6-methyladenosine (m6A) is one of the most prevalent and reversible forms of RNA methylation, with increasing evidence indicating its critical role in numerous physiological and pathological processes. m6A catalyzes messenger RNA(mRNA) as well as regulatory non-coding RNAs (ncRNAs), such as microRNAs, long non-coding RNAs, and circular RNAs. This modification modulates ncRNA fate and cell functions in various bioprocesses, including ncRNA splicing, maturity, export, and stability. Key m6A regulators, including writers, erasers, and readers, have been reported to modify the ncRNAs involved in fibrogenesis. NcRNAs affect fibrosis progression by targeting m6A regulators. The interactions between m6A and ncRNAs can influence multiple cellular life activities. In this review, we discuss the impact of the interaction between m6A modifications and ncRNAs on the pathological mechanisms of fibrosis, revealing the possibility of these interactions as diagnostic markers and therapeutic targets in fibrosis.

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.

Heterogeneity and interplay: the multifaceted role of cancer-associated fibroblasts in the tumor and therapeutic strategies

The journey of cancer development is a multifaceted and staged process. The array of treatments available for cancer varies significantly, dictated by the disease's type and stage. Cancer-associated fibroblasts (CAFs), prevalent across various cancer types and stages, play a pivotal role in tumor genesis, progression, metastasis, and drug resistance. The strategy of concurrently targeting cancer cells and CAFs holds great promise in cancer therapy. In this review, we focus intently on CAFs, delving into their critical role in cancer's progression. We begin by exploring the origins, classification, and surface markers of CAFs. Following this, we emphasize the key cytokines and signaling pathways involved in the interplay between cancer cells and CAFs and their influence on the tumor immune microenvironment. Additionally, we examine current therapeutic approaches targeting CAFs. This article underscores the multifarious roles of CAFs within the tumor microenvironment and their potential applications in cancer treatment, highlighting their importance as key targets in overcoming drug resistance and enhancing the efficacy of tumor therapies.

From Cell to Gene: Deciphering the Mechanism of Heart Failure With Single-Cell Sequencing

Heart failure (HF) is a prevalent cardiovascular disease with significant morbidity and mortality rates worldwide. Due to the intricate structure of the heart, diverse cell types, and the complex pathogenesis of HF, further in-depth investigation into the underlying mechanisms  is required. The elucidation of the heterogeneity of cardiomyocytes and the intercellular communication network is particularly important. Traditional high-throughput sequencing methods provide an average measure of gene expression, failing to capture the "heterogeneity" between cells and impacting the accuracy of gene function knowledge. In contrast, single-cell sequencing techniques allow for the amplification of the entire genome or transcriptome at the individual cell level, facilitating the examination of gene structure and expression with unparalleled precision. This approach offers valuable insights into disease mechanisms, enabling the identification of changes in cellular components and gene expressions during hypertrophy associated with HF. Moreover, it reveals distinct cell populations and their unique roles in the HF microenvironment, providing a comprehensive understanding of the cellular landscape that underpins HF pathogenesis. This review focuses on the insights provided by single-cell sequencing techniques into the mechanisms underlying HF and discusses the challenges encountered in current cardiovascular research.

Cardiac remodeling: novel pathophysiological mechanisms and therapeutic strategies

Morphological and structural remodeling of the heart, including cardiac hypertrophy and fibrosis, has been considered as a therapeutic target for heart failure for approximately three decades. Groundbreaking heart failure medications demonstrating reverse remodeling effects have contributed significantly to medical advancements. However, nearly 50% of heart failure patients still exhibit drug resistance, posing a challenge to the healthcare system. Recently, characteristics of heart failure resistant to ARBs and β-blockers have been defined, highlighting preserved systolic function despite impaired diastolic function, leading to the classification of heart failure with preserved ejection fraction (HFpEF). The pathogenesis and aetiology of HFpEF may be related to metabolic abnormalities, as evidenced by its mimicry through endothelial dysfunction and excessive intake of high-fat diets. Our recent findings indicate a significant involvement of mitochondrial hyper-fission in the progression of heart failure. This mitochondrial pathological remodeling is associated with redox imbalance, especially hydrogen sulphide accumulation due to abnormal electron leak in myocardium. In this review, we also introduce a novel therapeutic strategy for heart failure from the current perspective of mitochondrial redox-metabolic remodeling.

N6-Methyladenosine-mediated phase separation suppresses NOTCH1 expression and promotes mitochondrial fission in diabetic cardiac fibrosis

BACKGROUND

N6-methyladenosine (m6A) modification of messenger RNA (mRNA) is crucial for liquid-liquid phase separation in mammals. Increasing evidence indicates that liquid-liquid phase separation in proteins and RNAs affects diabetic cardiomyopathy. However, the molecular mechanism by which m6A-mediated phase separation regulates diabetic cardiac fibrosis remains elusive.

METHODS

Leptin receptor-deficient mice (db/db), cardiac fibroblast-specific Notch1 conditional knockout (POSTN-Cre × Notch1flox/flox) mice, and Cre mice were used to induce diabetic cardiac fibrosis. Adeno-associated virus 9 carrying cardiac fibroblast-specific periostin (Postn) promoter-driven small hairpin RNA targeting Alkbh5, Ythdf2, or Notch1, and the phase separation inhibitor 1,6-hexanediol were administered to investigate their roles in diabetic cardiac fibrosis. Histological and biochemical analyses were performed to determine how Alkbh5 and Ythdf2 regulate Notch1 expression in diabetic cardiac fibrosis. NOTCH1 was reconstituted in ALKBH5- and YTHDF2-deficient cardiac fibroblasts and mouse hearts to study its effects on mitochondrial fission and diabetic cardiac fibrosis. Heart tissue samples from patients with diabetic cardiomyopathy were used to validate our findings.

RESULTS

In mice with diabetic cardiac fibrosis, decreased Notch1 expression was accompanied by high m6A mRNA levels and mitochondrial fission. Fibroblast-specific deletion of Notch1 enhanced mitochondrial fission and cardiac fibroblast proliferation and induced diabetic cardiac fibrosis in mice. Notch1 downregulation was associated with Alkbh5-mediated m6A demethylation in the 3'UTR of Notch1 mRNA and elevated m6A mRNA levels. These elevated m6A levels in Notch1 mRNA markedly enhanced YTHDF2 phase separation, increased the recognition of m6A residues in Notch1 mRNA by YTHDF2, and induced Notch1 degradation. Conversely, epitranscriptomic downregulation rescues Notch1 expression, resulting in the opposite effects. Human heart tissues from patients with diabetic cardiomyopathy were used to validate the findings in mice with diabetic cardiac fibrosis.

CONCLUSIONS

We identified a novel epitranscriptomic mechanism by which m6A-mediated phase separation suppresses Notch1 expression, thereby promoting mitochondrial fission in diabetic cardiac fibrosis. Our findings provide new insights for the development of novel treatment approaches for patients with diabetic cardiac fibrosis.

Ischemic cardiac stromal fibroblast-derived protein mediators in the infarcted myocardium and transcriptomic profiling at single cell resolution

This article focuses on screening the major secreted proteins by the ischemia-challenged cardiac stromal fibroblasts (CF), the assessment of their expression status and functional role in the post-ischemic left ventricle (LV) and in the ischemia-challenged CF culture and to phenotype CF at single cell resolution based on the positivity of the identified mediators. The expression level of CRSP2, HSP27, IL-8, Cofilin-1, and HSP90 in the LV tissues following coronary artery bypass graft (CABG) and myocardial infarction (MI) and CF cells followed the screening profile derived from the MS/MS findings. The histology data unveiled ECM disorganization, inflammation and fibrosis reflecting the ischemic pathology. CRSP2, HSP27, and HSP90 were significantly upregulated in the LV-CABG tissues with a concomitant reduction ion LV-MI whereas Cofilin-1, IL8, Nrf2, and Troponin I were downregulated in LV-CABG and increased in LV-MI. Similar trends were exhibited by ischemic CF. Single cell transcriptomics revealed multiple sub-phenotypes of CF based on their respective upregulation of CRSP2, HSP27, IL-8, Cofilin-1, HSP90, Troponin I and Nrf2 unveiling pathological and pro-healing phenotypes. Further investigations regarding the underlying signaling mechanisms and validation of sub-populations would offer novel translational avenues for the management of cardiac diseases.

Cardiac macrophages in maintaining heart homeostasis and regulating ventricular remodeling of heart diseases

Macrophages are most important immune cell population in the heart. Cardiac macrophages have broad-spectrum and heterogeneity, with two extreme polarization phenotypes: M1 pro-inflammatory macrophages (CCR2-ly6Chi) and M2 anti-inflammatory macrophages (CCR2-ly6Clo). Cardiac macrophages can reshape their polarization states or phenotypes to adapt to their surrounding microenvironment by altering metabolic reprogramming. The phenotypes and polarization states of cardiac macrophages can be defined by specific signature markers on the cell surface, including tumor necrosis factor α, interleukin (IL)-1β, inducible nitric oxide synthase (iNOS), C-C chemokine receptor type (CCR)2, IL-4 and arginase (Arg)1, among them, CCR2+/- is one of most important markers which is used to distinguish between resident and non-resident cardiac macrophage as well as macrophage polarization states. Dedicated balance between M1 and M2 cardiac macrophages are crucial for maintaining heart development and cardiac functional and electric homeostasis, and imbalance between macrophage phenotypes may result in heart ventricular remodeling and various heart diseases. The therapy aiming at specific target on macrophage phenotype is a promising strategy for treatment of heart diseases. In this article, we comprehensively review cardiac macrophage phenotype, metabolic reprogramming, and their role in maintaining heart health and mediating ventricular remodeling and potential therapeutic strategy in heart diseases.

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.

Plasma Olink Proteomics Reveals Novel Biomarkers for Prediction and Diagnosis in Dilated Cardiomyopathy with Heart Failure

In this study, we utilized the Olink Cardiovascular III panel to compare the expression levels of 92 cardiovascular-related proteins between patients with dilated cardiomyopathy combined with heart failure (DCM-HF) (n = 20) and healthy normal people (Normal) (n = 18). The top five most significant proteins, including SPP1, IGFBP7, F11R, CHI3L1, and Plaur, were selected by Olink proteomics. These proteins were further validated using ELISA in plasma samples collected from an additional cohort. ELISA validation confirmed significant increases in SPP1, IGFBP7, F11R, CHI3L1, and Plaur in DCM-HF patients compared to healthy controls. GO and KEGG analysis indicated that NT-pro BNP, SPP1, IGFBP7, F11R, CHI3L1, Plaur, BLM hydrolase, CSTB, Gal-4, CCL15, CDH5, SR-PSOX, and CCL2 were associated with DCM-HF. Correlation analysis revealed that these 13 differentially expressed proteins have strong correlations with clinical indicators such as LVEF and NT-pro BNP, etc. Additionally, in the GEO-DCM data sets, the combined diagnostic value of these five core proteins AUC values of 0.959, 0.773, and 0.803, respectively indicating the predictive value of the five core proteins for DCM-HF. Our findings suggest that these proteins may be useful biomarkers for the diagnosis and prediction of DCM-HF, and further research is prompted to explore their potential as therapeutic targets.

Ischemic-Preconditioning Induced Serum Exosomal miR-133a-3p Improved Post-Myocardial Infarction Repair via Targeting LTBP1 and PPP2CA

Background

Ischemic preconditioning-induced serum exosomes (IPC-exo) protected rat heart against myocardial ischemia/reperfusion injury. However, whether IPC-exo regulate replacement fibrosis after myocardial infarction (MI) and the underlying mechanisms remain unclear. MicroRNAs (miRs) are important cargos of exosomes and play an essential role in cardioprotection. We aim to investigate whether IPC-exo regulate post-MI replacement fibrosis by transferring cardioprotective miRs and its action mechanism.

Methods

Exosomes obtained from serum of adult rats in control (Con-exo) and IPC groups were identified and analyzed, subsequently intracardially injected into MI rats following ligation. Their miRs profiles were identified using high-throughput miR sequencing to identify target miRs for bioinformatics analysis. Luciferase reporter assays confirmed target genes of selected miRs. IPC-exo transfected with selected miRs antagomir or NC were intracardially administered to MI rats post-ligation. Cardiac function and degree of replacement fibrosis were detected 4 weeks post-MI.

Results

IPC-exo exerted cardioprotective effects against excessive replacement fibrosis. MiR sequencing and RT-qPCR identified miR-133a-3p as most significantly different between IPC-exo and Con-exo. MiR-133a-3p directly targeted latent transforming growth factor beta binding protein 1 (LTBP1) and protein phosphatase 2, catalytic subunit, alpha isozyme (PPP2CA). KEGG analysis showed that transforming growth factor-β (TGF-β) was one of the most enriched signaling pathways with miR-133a-3p. Comparing to injection of IPC-exo transfected with miR-133a-3p antagomir NC, injecting IPC-exo transfected with miR-133a-3p antagomir abolished protective effects of IPC-exo on declining excessive replacement fibrosis and cardiac function enhancement, while increasing the messenger RNA and protein expression of LTBP1, PPP2CA, and TGF-β1in MI rats.

Conclusion

IPC-exo inhibit excessive replacement fibrosis and improve cardiac function post-MI by transferring miR-133a-3p, the mechanism is associated with directly targeting LTBP1 and PPP2CA, and indirectly regulating TGF-β pathway in rats. Our finding provides potential therapeutic effect of IPC-induced exosomal miR-133a-3p for cardiac repair.

IGFBP7 mediates oxLDL-induced human vascular endothelial cell injury by suppressing the expression of SIRT1

Endothelial cell injury plays an important role in initiating atherosclerotic lesion formation. Insulin-like growth factor binding protein 7 (IGFBP7) is known to modulate the behaviors of tumor-associated endothelial cells. This study was conducted to test whether IGFBP7 is involved in endothelial cell injury during atherosclerosis. Oxidized low-density lipoprotein (oxLDL) treatment was used to mimic atherosclerosis-related endothelial cell apoptosis and inflammation response. Small interfering RNA (siRNA) technology was employed to deplete IGFBP7 expression in human aortic endothelial cells (HAECs). HAECs were exposed to recombinant human IGFBP7 protein to evaluate the function of IGFBP7. Notably, IGFBP7 expression in HAECs was induced by oxLDL treatment. Knockdown of IGFBP7 or treatment with anti-IGFBP7 abolished oxLDL-induced apoptosis and inflammation in HAECs. Moreover, recombinant IGFBP7 (40 ng/mL but not 25 ng/mL) promoted apoptosis and inflammation in HAECs. IGFBP7 co-localized with CD93 on the surface of HAECs. A mechanistic investigation uncovered that IGFBP7 induced endothelial cell injury through interaction with CD93 and reduction of SIRT1 expression via an autocrine manner. Overexpression of SIRT1 rescued IGFBP7-induced phenotype in HAECs. Taken together, IGFBP7 is induced by oxLDL and mediates oxLDL-induced endothelial cell apoptosis and inflammation, likely through downregulation of SIRT1. These observations support a rationale to prevent atherosclerosis by targeting IGFBP7 activity.

Combining Bulk and Single Cell RNA-Sequencing Data to Identify Hub Genes of Fibroblasts in Dilated Cardiomyopathy

Background

Dilated cardiomyopathy (DCM) is the second leading cause of heart failure, with intricate pathophysiological underpinnings. In order to shed fresh light on the mechanistic research of DCM, we combined bulk RNA-seq and single-cell RNA-seq (scRNA-seq) data to examine significant cells and genes implicated in the disease.

Methods

This analysis employed publicly accessible bulk RNA-seq and scRNA-seq DCM datasets. The scRNA-seq data underwent normalization, principal component, and t-distribution stochastic neighbor embedding analysis. Cell-to-cell communication networks and activity analysis were conducted using CellChat. Utilizing enrichment analysis, the marker genes' role in the active cells was evaluated. After screening by limma software and weighted gene co-expression network analysis, the differentially expressed genes (DEGs) served as hub genes. Furthermore, these hub genes were subjected to immunological studies, transcription factor expression, and gene set enrichment. Lastly, the expression of the four hub genes and their connection to DCM were verified using the rat models.

Results

Fibroblasts and monocytes were chosen as hub cells from among the eight identified cell clusters; their marker genes intersected with DEGs to yield six hub genes. In addition, the six hub genes and the essential module genes intersected to yield four essential genes (ASPN, SFRP4, LUM, and FRZB) that were connected to the Wnt signaling pathway and highly expressed in fibroblast. The four hub DEGs had an expression pattern in the DCM rat model experiment results that was in line with the findings of the bioinformatics study. Additionally, there was a strong correlation between decreased cardiac function and the up-regulation of ASPN, SFRP4, LUM, and FRZB.

Conclusion

Ultimately, bulk RNA-seq and scRNA-seq data identified fibroblasts and monocytes as the main cell types implicated in DCM. The highly expressed genes ASPN, FRZB, LUM, and SFRP4 in fibroblasts may aid in the mechanistic investigation of DCM.

The role of macrophages in fibrosis of chronic kidney disease

Macrophages are widely distributed throughout various tissues of the body, and mounting evidence suggests their involvement in regulating the tissue microenvironment, thereby influencing disease onset and progression through direct or indirect actions. In chronic kidney disease (CKD), disturbances in renal functional homeostasis lead to inflammatory cell infiltration, tubular expansion, glomerular atrophy, and subsequent renal fibrosis. Macrophages play a pivotal role in this pathological process. Therefore, understanding their role is imperative for investigating CKD progression, mitigating its advancement, and offering novel research perspectives for fibrosis treatment from an immunological standpoint. This review primarily delves into the intrinsic characteristics of macrophages, their origins, diverse subtypes, and their associations with renal fibrosis. Particular emphasis is placed on the transition between M1 and M2 phenotypes. In late-stage CKD, there is a shift from the M1 to the M2 phenotype, accompanied by an increased prevalence of M2 macrophages. This transition is governed by the activation of the TGF-β1/SMAD3 and JAK/STAT pathways, which facilitate macrophage-to-myofibroblast transition (MMT). The tyrosine kinase Src is involved in both signaling cascades. By thoroughly elucidating macrophage functions and comprehending the modes and molecular mechanisms of macrophage-fibroblast interaction in the kidney, novel, tailored therapeutic strategies for preventing or attenuating the progression of CKD can be developed.

Vaccine Therapy for Heart Failure Targeting the Inflammatory Cytokine Igfbp7

BACKGROUND

The heart comprises many types of cells such as cardiomyocytes, endothelial cells (ECs), fibroblasts, smooth muscle cells, pericytes, and blood cells. Every cell type responds to various stressors (eg, hemodynamic overload and ischemia) and changes its properties and interrelationships among cells. To date, heart failure research has focused mainly on cardiomyocytes; however, other types of cells and their cell-to-cell interactions might also be important in the pathogenesis of heart failure.

METHODS

Pressure overload was imposed on mice by transverse aortic constriction and the vascular structure of the heart was examined using a tissue transparency technique. Functional and molecular analyses including single-cell RNA sequencing were performed on the hearts of wild-type mice and EC-specific gene knockout mice. Metabolites in heart tissue were measured by capillary electrophoresis-time of flight-mass spectrometry system. The vaccine was prepared by conjugating the synthesized epitope peptides with keyhole limpet hemocyanin and administered to mice with aluminum hydroxide as an adjuvant. Tissue samples from heart failure patients were used for single-nucleus RNA sequencing to examine gene expression in ECs and perform pathway analysis in cardiomyocytes.

RESULTS

Pressure overload induced the development of intricately entwined blood vessels in murine hearts, leading to the accumulation of replication stress and DNA damage in cardiac ECs. Inhibition of cell proliferation by a cyclin-dependent kinase inhibitor reduced DNA damage in ECs and ameliorated transverse aortic constriction-induced cardiac dysfunction. Single-cell RNA sequencing analysis revealed upregulation of Igfbp7 (insulin-like growth factor-binding protein 7) expression in the senescent ECs and downregulation of insulin signaling and oxidative phosphorylation in cardiomyocytes of murine and human failing hearts. Overexpression of Igfbp7 in the murine heart using AAV9 (adeno-associated virus serotype 9) exacerbated cardiac dysfunction, while EC-specific deletion of Igfbp7 and the vaccine targeting Igfbp7 ameliorated cardiac dysfunction with increased oxidative phosphorylation in cardiomyocytes under pressure overload.

CONCLUSIONS

Igfbp7 produced by senescent ECs causes cardiac dysfunction and vaccine therapy targeting Igfbp7 may be useful to prevent the development of heart failure.

Insulin-like growth factor-binding protein 7 (IGFBP7): A microenvironment-dependent regulator of angiogenesis and vascular remodeling

Insulin-like Growth Factor-Binding Protein 7 (IGFBP7) is an extracellular matrix (ECM) glycoprotein, highly enriched in activated vasculature during development, physiological and pathological tissue remodeling. Despite decades of research, its role in tissue (re-)vascularization is highly ambiguous, exhibiting pro- and anti-angiogenic properties in different tissue remodeling states. IGFBP7 has multiple binding partners, including structural ECM components, cytokines, chemokines, as well as several receptors. Based on current evidence, it is suggested that IGFBP7's bioactivity is strongly dependent on the microenvironment it is embedded in. Current studies indicate that during physiological angiogenesis, IGFBP7 promotes endothelial cell attachment, luminogenesis, vessel stabilization and maturation. Its effects on other stages of angiogenesis and vessel function remain to be determined. IGFBP7 also modulates the pro-angiogenic properties of other signaling factors, such as VEGF-A and IGF, and potentially acts as a growth factor reservoir, while its actual effects on the factors' signaling may depend on the environment IGFBP7 is embedded in. Besides (re-)vascularization, IGFBP7 clearly promotes progenitor and stem cell commitment and may exhibit anti-inflammatory and anti-fibrotic properties. Nonetheless, its role in inflammation, immunomodulation, fibrosis and cellular senescence is again likely to be context-dependent. Future studies are required to shed more light on the intricate functioning of IGFBP7.

Knockout of C1q/tumor necrosis factor-related protein-9 aggravates cardiac fibrosis in diabetic mice by regulating YAP-mediated autophagy

Introduction

Diabetic cardiomyopathy (DCM) is predominantly distinguished by impairment in ventricular function and myocardial fibrosis. Previous studies revealed the cardioprotective properties of C1q/tumor necrosis factor-related protein 9 (CTRP9). However, whether CTRP9 affects diabetic myocardial fibrosis and its underlying mechanisms remains unclear.

Methods

We developed a type 1 diabetes (T1DM) model in CTRP9-KO mice via streptozotocin (STZ) induction to examine cardiac function, histopathology, fibrosis extent, Yes-associated protein (YAP) expression, and the expression of markers for autophagy such LC3-II and p62. Additionally, we analyzed the direct impact of CTRP9 on high glucose (HG)-induced transdifferentiation, autophagic activity, and YAP protein levels in cardiac fibroblasts.

Results

In diabetic mice, CTRP9 expression was decreased in the heart. The absence of CTRP9 aggravated cardiac dysfunction and fibrosis in mice with diabetes, alongside increased YAP expression and impaired autophagy. In vitro, HG induced the activation of myocardial fibroblasts, which demonstrated elevated cell proliferation, collagen production, and α-smooth muscle actin (α-SMA) expression. CTRP9 countered these adverse effects by restoring autophagy and reducing YAP protein levels in cardiac fibroblasts. Notably, the protective effects of CTRP9 were negated by the inhibition of autophagy with chloroquine (CQ) or by YAP overexpression through plasmid intervention. Notably, the protective effect of CTRP9 was negated by inhibition of autophagy caused by chloroquine (CQ) or plasmid intervention with YAP overexpression.

Discussion

Our findings suggest that CTRP9 can enhance cardiac function and mitigate cardiac remodeling in DCM through the regulation of YAP-mediated autophagy. CTRP9 holds promise as a potential candidate for pharmacotherapy in managing diabetic cardiac fibrosis.

IGFBP7 promotes endothelial cell repair in the recovery phase of acute lung injury

IGFBP7 has been found to play an important role in inflammatory diseases, such as acute lung injury (ALI). However, the role of IGFBP7 in different stages of inflammation remains unclear. Transcriptome sequencing was used to identify the regulatory genes of IGFBP7, and endothelial IGFBP7 expression was knocked down using Aplnr-Dre mice to evaluate the endothelial proliferation capacity. The expression of proliferation-related genes was detected by Western blotting and RT-PCR assays. In the present study, we found that knockdown of IGFBP7 in endothelial cells significantly decreases the expression of endothelial cell proliferation-related genes and cell number in the recovery phase but not in the acute phase of ALI. Mechanistically, using bulk-RNA sequencing and CO-IP, we found that IGFBP7 promotes phosphorylation of FOS and subsequently up-regulates YAP1 molecules, thereby promoting endothelial cell proliferation. This study indicated that IGFBP7 has diverse roles in different stages of ALI, which extends the understanding of IGFBP7 in different stages of ALI and suggests that IGFBP7 as a potential therapeutic target in ALI needs to take into account the period specificity of ALI.

Blood-based cardiometabolic phenotypes in atrial fibrillation and their associated risk: EAST-AFNET 4 biomolecule study

AIMS

Atrial fibrillation (AF) and concomitant cardiometabolic disease processes interact and combine to lead to adverse events, such as stroke, heart failure, myocardial infarction, and cardiovascular death. Circulating biomolecules provide quantifiable proxies for cardiometabolic disease processes. The aim of this study was to test whether biomolecule combinations can define phenotypes in patients with AF.

METHODS AND RESULTS

This pre-specified analysis of the EAST-AFNET 4 biomolecule study assigned patients to clusters using polytomous variable latent-class analysis based on baseline concentrations of 13 precisely quantified biomolecules potentially reflecting ageing, cardiac fibrosis, metabolic dysfunction, oxidative stress, cardiac load, endothelial dysfunction, and inflammation. In each cluster, rates of cardiovascular death, stroke, or hospitalization for heart failure or acute coronary syndrome, the primary outcome of EAST-AFNET 4, were calculated and compared between clusters over median 5.1 years follow-up. Findings were independently validated in a prospective cohort of 748 patients with AF (BBC-AF; median follow-up 2.9 years).Unsupervised biomolecule analysis assigned 1586 patients (71 years old, 46% women) into four clusters. The highest risk cluster was dominated by elevated bone morphogenetic protein 10, insulin-like growth factor-binding protein 7, N-terminal pro-B-type natriuretic peptide, angiopoietin 2, and growth differentiation factor 15. Patients in the lowest risk cluster showed low concentrations of these biomolecules. Two intermediate-risk clusters differed by high or low concentrations of C-reactive protein, interleukin-6, and D-dimer. Patients in the highest risk cluster had a five-fold higher cardiovascular event rate than patients in the low-risk cluster. Early rhythm control was effective across clusters (Pinteraction = 0.63). Sensitivity analyses and external validation in BBC-AF replicated clusters and risk gradients.

CONCLUSION

Biomolecule concentrations identify cardiometabolic subphenotypes in patients with AF at high and low cardiovascular risk.

Activated Clec4nhi Neutrophils Aggravate Lung Injury in an Endothelial IGFBP7-Dependent Manner

The role of endothelial cells in acute lung injury (ALI) has been widely elaborated, but little is known about the role of different subtypes of endothelial cells in ALI. ALI models were established by lipopolysaccharide. Single-cell RNA sequencing was used to identify differential molecules in endothelial subtypes and the heterogeneity of lung immune cells. Specific antibodies were used to block insulin-like growth factor binding protein 7 (IGFBP7), and AAVshIGP7 was used to specifically knock down IGFBP7. Here, we found that IGFBP7 was the most differentially expressed molecule in diverse subsets of endothelial cells and that IGFBP7 was strongly associated with inflammatory responses. Elevated IGFBP7 significantly exacerbated barrier dysfunction in ALI, whereas blockade of IGFBP7 partially reversed barrier damage. General capillary cells are the primary source of elevated serum IGFBP7 after ALI. Using single-cell RNA sequencing, we identified significantly increased Clec4nhi neutrophils in mice with ALI, whereas IGFBP7 knockdown significantly reduced infiltration of Clec4nhi cells and mitigated barrier dysfunction in ALI. In addition, we found that IGFBP7 activated the NF-κB signaling axis by promoting phosphorylation and ubiquitination degradation of F-box/WD repeat-containing protein 2 (FBXW2), thereby exacerbating barrier dysfunction in ALI. Taken together, our data indicate that blockade of serum IGFBP7 or IGFBP7 depletion in general capillary cells reversed barrier damage in ALI. Therefore, targeting IGFBP7 depletion could be a novel strategy for treating ALI.

Targeting tumor suppressor p53 for organ fibrosis therapy

Fibrosis is a reparative and progressive process characterized by abnormal extracellular matrix deposition, contributing to organ dysfunction in chronic diseases. The tumor suppressor p53 (p53), known for its regulatory roles in cell proliferation, apoptosis, aging, and metabolism across diverse tissues, appears to play a pivotal role in aggravating biological processes such as epithelial-mesenchymal transition (EMT), cell apoptosis, and cell senescence. These processes are closely intertwined with the pathogenesis of fibrotic disease. In this review, we briefly introduce the background and specific mechanism of p53, investigate the pathogenesis of fibrosis, and further discuss p53's relationship and role in fibrosis affecting the kidney, liver, lung, and heart. In summary, targeting p53 represents a promising and innovative therapeutic approach for the prevention and treatment of organ fibrosis.

Spatial Transcriptomics: A Powerful Tool in Disease Understanding and Drug Discovery

Recent advancements in modern science have provided robust tools for drug discovery. The rapid development of transcriptome sequencing technologies has given rise to single-cell transcriptomics and single-nucleus transcriptomics, increasing the accuracy of sequencing and accelerating the drug discovery process. With the evolution of single-cell transcriptomics, spatial transcriptomics (ST) technology has emerged as a derivative approach. Spatial transcriptomics has emerged as a hot topic in the field of omics research in recent years; it not only provides information on gene expression levels but also offers spatial information on gene expression. This technology has shown tremendous potential in research on disease understanding and drug discovery. In this article, we introduce the analytical strategies of spatial transcriptomics and review its applications in novel target discovery and drug mechanism unravelling. Moreover, we discuss the current challenges and issues in this research field that need to be addressed. In conclusion, spatial transcriptomics offers a new perspective for drug discovery.

The local mechanosensitive response of primary cardiac fibroblasts is influenced by the microenvironment mechanics

Cardiac fibroblasts (CFs) are essential for preserving myocardial integrity and function. They can detect variations in cardiac tissue stiffness using various cellular mechanosensors, including the Ca2+ permeable mechanosensitive channel Piezo1. Nevertheless, how CFs adapt the mechanosensitive response to stiffness changes remains unclear. In this work we adopted a multimodal approach, combining the local mechanical stimulation (from 10 pN to 350 nN) with variations of culture substrate stiffness. We found that primary rat CFs cultured on stiff (GPa) substrates showed a broad Piezo1 distribution in the cell with particular accumulation at the mitochondria membrane. CFs displayed a force-dependent behavior in both calcium uptake and channel activation probability, showing a threshold at 300 nN, which involves both cytosolic and mitochondrial Ca2+ mobilization. This trend decreases as the myofibroblast phenotype within the cell population increases, following a possible Piezo1 accumulation at focal adhesion sites. In contrast, the inhibition of fibroblasts to myofibroblasts transition with soft substrates (kPa) considerably reduces both mechanically- and chemically-induced Piezo1 activation and expression. Our findings shed light on how Piezo1 function and expression are regulated by the substrate stiffness and highlight its involvement in the environment-mediated modulation of CFs mechanosensitivity.