Down-regulation of Beclin1 promotes direct cardiac reprogramming

Crosstalk among Reactive Oxygen Species, Autophagy and Metabolism in Myocardial Ischemia and Reperfusion Stages

Myocardial ischemia is the most common cardiovascular disease. Reperfusion, an important myocardial ischemia tool, causes unexpected and irreversible damage to cardiomyocytes, resulting in myocardial ischemia/reperfusion (MI/R) injury. Upon stress, especially oxidative stress induced by reactive oxygen species (ROS), autophagy, which degrades the intracellular energy storage to produce metabolites that are recycled into metabolic pathways to buffer metabolic stress, is initiated during myocardial ischemia and MI/R injury. Excellent cardioprotective effects of autophagy regulators against MI and MI/R have been reported. Reversing disordered cardiac metabolism induced by ROS also exhibits cardioprotective action in patients with myocardial ischemia. Herein, we review current knowledge on the crosstalk between ROS, cardiac autophagy, and metabolism in myocardial ischemia and MI/R. Finally, we discuss the possible regulators of autophagy and metabolism that can be exploited to harness the therapeutic potential of cardiac metabolism and autophagy in the diagnosis and treatment of myocardial ischemia and MI/R.

Beclin-1-Derived Peptide MP1 Attenuates Renal Fibrosis by Inhibiting the Wnt/β-Catenin Pathway

Renal fibrosis is distinguished by the abnormal deposition of extracellular matrix and progressive loss of nephron function, with a lack of effective treatment options in clinical practice. In this study, we discovered that the Beclin-1-derived peptide MP1 significantly inhibits the abnormal expression of fibrosis and epithelial-mesenchymal transition-related markers, including α-smooth muscle actin, fibronectin, collagen I, matrix metallopeptidase 2, Snail1, and vimentin both in vitro and in vivo. H&E staining was employed to evaluate renal function, while serum creatinine (Scr) and blood urea nitrogen (BUN) were used as main indices to assess pathologic changes in the obstructed kidney. The results demonstrated that daily treatment with MP1 during the 14-day experiment significantly alleviated renal dysfunction and changes in Scr and BUN in mice with unilateral ureteral obstruction. Mechanistic research revealed that MP1 was found to have a significant inhibitory effect on the expression of crucial components involved in both the Wnt/β-catenin and transforming growth factor (TGF)-β/Smad pathways, including β-catenin, C-Myc, cyclin D1, TGF-β1, and p-Smad/Smad. However, MP1 exhibited no significant impact on either the LC3II/LC3I ratio or P62 levels. These findings indicate that MP1 improves renal physiologic function and mitigates the fibrosis progression by inhibiting the Wnt/β-catenin pathway. Our study suggests that MP1 represents a promising and novel candidate drug precursor for the treatment of renal fibrosis. SIGNIFICANCE STATEMENT: This study indicated that the Beclin-1-derived peptide MP1 effectively mitigated renal fibrosis induced by unilateral ureteral obstruction through inhibiting the Wnt/β-catenin pathway and transforming growth factor-β/Smad pathway, thereby improving renal physiological function. Importantly, unlike other Beclin-1-derived peptides, MP1 exhibited no significant impact on autophagy in normal cells. MP1 represents a promising and novel candidate drug precursor for the treatment of renal fibrosis focusing on Beclin-1 derivatives and Wnt/β-catenin pathway.

The nonautophagic functions of autophagy-related proteins

ABBREVIATIONS

ATG: autophagy related; BECN1: beclin 1; cAMP: cyclic adenosine monophosphate; dsDNA: double-stranded DNA; EMT: epithelial-mesenchymal transition; IFN: interferon; ISCs: intestinal stem cells; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MAPK/JNK: mitogen-activated protein kinase/c-Jun N-terminal kinases; MTOR: mechanistic target of rapamycin kinase; STING1: stimulator of interferon response cGAMP interactor 1; UVRAG: UV radiation resistance associated; VPS: vacuolar protein sorting.

Vitamin C facilitates direct cardiac reprogramming by inhibiting reactive oxygen species

BACKGROUND

After myocardial infarction, the lost myocardium is replaced by fibrotic tissue, eventually progressively leading to myocardial dysfunction. Direct reprogramming of fibroblasts into cardiomyocytes via the forced overexpression of cardiac transcription factors Gata4, Mef2c, and Tbx5 (GMT) offers a promising strategy for cardiac repair. The limited reprogramming efficiency of this approach, however, remains a significant challenge.

METHODS

We screened seven factors capable of improving direct cardiac reprogramming of both mice and human fibroblasts by evaluating small molecules known to be involved in cardiomyocyte differentiation or promoting human-induced pluripotent stem cell reprogramming.

RESULTS

We found that vitamin C (VitC) significantly increased cardiac reprogramming efficiency when added to GMT-overexpressing fibroblasts from human and mice in 2D and 3D model. We observed a significant increase in reactive oxygen species (ROS) generation in human and mice fibroblasts upon Doxy induction, and ROS generation was subsequently reduced upon VitC treatment, associated with increased reprogramming efficiency. However, upon treatment with dehydroascorbic acid, a structural analog of VitC but lacking antioxidant properties, no difference in reprogramming efficiency was observed, suggesting that the effect of VitC in enhancing cardiac reprogramming is partly dependent of its antioxidant properties.

CONCLUSIONS

Our findings demonstrate that VitC supplementation significantly enhances the efficiency of cardiac reprogramming, partially by suppressing ROS production in the presence of GMT.

Fibroblast Reprogramming in Cardiac Repair

Cardiovascular disease is one of the major causes of death worldwide. Limited proliferative capacity of adult mammalian cardiomyocytes has prompted researchers to exploit regenerative therapy after myocardial injury, such as myocardial infarction, to attenuate heart dysfunction caused by such injury. Direct cardiac reprogramming is a recently emerged promising approach to repair damaged myocardium by directly converting resident cardiac fibroblasts into cardiomyocyte-like cells. The achievement of in vivo direct reprogramming of fibroblasts has been shown, by multiple laboratories independently, to improve cardiac function and mitigate fibrosis post-myocardial infarction, which holds great potential for clinical application. There have been numerous pieces of valuable work in both basic and translational research to enhance our understanding and continued refinement of direct cardiac reprogramming in recent years. However, there remain many challenges to overcome before we can truly take advantage of this technique to treat patients with ischemic cardiac diseases. Here, we review recent progress of fibroblast reprogramming in cardiac repair, including the optimization of several reprogramming strategies, mechanistic exploration, and translational efforts, and we make recommendations for future research to further understand and translate direct cardiac reprogramming from bench to bedside. Challenges relating to these efforts will also be discussed.

Can we stop one heart from breaking: triumphs and challenges in cardiac reprogramming

Ischemic cardiac injury causes irreversible muscle loss and scarring, but recent years have seen dramatic advances in cardiac reprogramming, the field focused on regenerating cardiac muscle. With SARS-CoV2 increasing the age-adjusted cardiovascular disease mortality rate, it is worth evaluating the state of this field. Here, we summarize novel innovations in reprogramming strategies, insights into their mechanisms, and technologies for factor delivery. We also propose a broad model of reprogramming to suggest directions for future research. Poet Emily Dickinson wrote, "If I can stop one heart from breaking, I shall not live in vain." Today, researchers studying cardiac reprogramming view this line as a call to action to translate this revolutionary approach into life-saving treatments for patients with cardiovascular diseases.

Targeting gut microbiota in aging-related cardiovascular dysfunction: focus on the mechanisms

The global population is aging and age-related cardiovascular disease is increasing. Even after controlling for cardiovascular risk factors, readmission and mortality rates remain high. In recent years, more and more in-depth studies have found that the composition of the gut microbiota and its metabolites, such as trimethylamine N-oxide (TMAO), bile acids (BAs), and short-chain fatty acids (SCFAs), affect the occurrence and development of age-related cardiovascular diseases through a variety of molecular pathways, providing a new target for therapy. In this review, we discuss the relationship between the gut microbiota and age-related cardiovascular diseases, and propose that the gut microbiota could be a new therapeutic target for preventing and treating cardiovascular diseases.

Translational landscape of direct cardiac reprogramming reveals a role of Ybx1 in repressing cardiac fate acquisition

Direct reprogramming of fibroblasts into induced cardiomyocytes holds great promise for heart regeneration. Although considerable progress has been made in understanding the transcriptional and epigenetic mechanisms of iCM reprogramming, its translational regulation remains largely unexplored. Here, we characterized the translational landscape of iCM reprogramming through integrative ribosome and transcriptomic profiling, and found extensive translatome repatterning during this process. Loss of function screening for translational regulators uncovered Ybx1 as a critical barrier to iCM induction. In a mouse model of myocardial infarction, removing Ybx1 enhanced in vivo reprogramming, resulting in improved heart function and reduced scar size. Mechanistically, Ybx1 depletion de-repressed the translation of its direct targets SRF and Baf60c, both of which mediated the effect of Ybx1 depletion on iCM generation. Furthermore, removal of Ybx1 allowed single factor Tbx5-mediated iCM conversion. In summary, this study revealed a new layer of regulatory mechanism that controls cardiac reprogramming at the translational level.

Amending the injured heart by in vivo reprogramming

Ischemic heart injury causes death of cardiomyocyte (CM), formation of a fibrotic scar, and often adverse cardiac remodeling, resulting in chronic heart failure. Therapeutic interventions have lowered myocardial damage and improved heart function, but pharmacological treatment of heart failure has only shown limited progress in recent years. Over the past two decades, different approaches have been pursued to regenerate the heart, by transplantation of newly generated CMs derived from pluripotent stem cells, generation of new CMs by reprogramming of cardiac fibroblasts, or by activating proliferation of preexisting CMs. Here, we summarize recent progress in the development of strategies for in situ generation of new CMs, review recent advances in understanding the underlying mechanisms, and discuss the challenges and future directions of the field.

Autophagy in Heart Failure: Insights into Mechanisms and Therapeutic Implications

Autophagy, a dynamic and complex process responsible for the clearance of damaged cellular components, plays a crucial role in maintaining myocardial homeostasis. In the context of heart failure, autophagy has been recognized as a response mechanism aimed at counteracting pathogenic processes and promoting cellular health. Its relevance has been underscored not only in various animal models, but also in the human heart. Extensive research efforts have been dedicated to understanding the significance of autophagy and unravelling its complex molecular mechanisms. This review aims to consolidate the current knowledge of the involvement of autophagy during the progression of heart failure. Specifically, we provide a comprehensive overview of published data on the impact of autophagy deregulation achieved by genetic modifications or by pharmacological interventions in ischemic and non-ischemic models of heart failure. Furthermore, we delve into the intricate molecular mechanisms through which autophagy regulates crucial cellular processes within the three predominant cell populations of the heart: cardiomyocytes, cardiac fibroblasts, and endothelial cells. Finally, we emphasize the need for future research to unravel the therapeutic potential associated with targeting autophagy in the management of heart failure.

Cellular reprogramming of fibroblasts in heart regeneration

Myocardial infarction causes the loss of cardiomyocytes and the formation of cardiac fibrosis due to the activation of cardiac fibroblasts, leading to cardiac dysfunction and heart failure. Unfortunately, current therapeutic interventions can only slow the disease progression. Furthermore, they cannot fully restore cardiac function, likely because the adult human heart lacks sufficient capacity to regenerate cardiomyocytes. Therefore, intensive efforts have focused on developing therapeutics to regenerate the damaged heart. Several strategies have been intensively investigated, including stimulation of cardiomyocyte proliferation, transplantation of stem cell-derived cardiomyocytes, and conversion of fibroblasts into cardiac cells. Resident cardiac fibroblasts are critical in the maintenance of the structure and contractility of the heart. Fibroblast plasticity makes this type of cells be reprogrammed into many cell types, including but not limited to induced pluripotent stem cells, induced cardiac progenitor cells, and induced cardiomyocytes. Fibroblasts have become a therapeutic target due to their critical roles in cardiac pathogenesis. This review summarizes the reprogramming of fibroblasts into induced pluripotent stem cell-derived cardiomyocytes, induced cardiac progenitor cells, and induced cardiomyocytes to repair a damaged heart, outlines recent findings in utilizing fibroblast-derived cells for heart regeneration, and discusses the limitations and challenges.

Identification of mitophagy-related genes with potential clinical utility in myocardial infarction at transcriptional level

Background

Myocardial infarction (MI) ranks among the most prevalent cardiovascular diseases. Insufficient blood flow to the coronary arteries always leads to ischemic necrosis of the cardiac muscle. However, the mechanism of myocardial injury after MI remains unclear. This article aims to explore the potential common genes between mitophagy and MI and to construct a suitable prediction model.

Methods

Two Gene Expression Omnibus (GEO) datasets (GSE62646 and GSE59867) were used to screen the differential expression genes in peripheral blood. SVM, RF, and LASSO algorithm were employed to find MI and mitophagy-related genes. Moreover, DT, KNN, RF, SVM and LR were conducted to build the binary models, and screened the best model to further external validation (GSE61144) and internal validation (10-fold cross validation and Bootstrap), respectively. The performance of various machine learning models was compared. In addition, immune cell infiltration correlation analysis was conducted with MCP-Counter and CIBERSORT.

Results

We finally identified ATG5, TOMM20, MFN2 transcriptionally differed between MI and stable coronary artery diseases. Both internal and external validation supported that these three genes could accurately predict MI withAUC = 0.914 and 0.930 by logistic regression, respectively. Additionally, functional analysis suggested that monocytes and neutrophils might be involved in mitochondrial autophagy after myocardial infarction.

Conclusion

The data showed that the transcritional levels of ATG5, TOMM20 and MFN2 in patients with MI were significantly different from the control group, which might be helpful to further accurately diagnose diseases and have potential application value in clinical practice.

Autophagy, innate immunity, and cardiac disease

Autophagy is an evolutionarily conserved mechanism of cell adaptation to metabolic and environmental stress. It mediates the disposal of protein aggregates and dysfunctional organelles, although non-conventional features have recently emerged to broadly extend the pathophysiological relevance of autophagy. In baseline conditions, basal autophagy critically regulates cardiac homeostasis to preserve structural and functional integrity and protect against cell damage and genomic instability occurring with aging. Moreover, autophagy is stimulated by multiple cardiac injuries and contributes to mechanisms of response and remodeling following ischemia, pressure overload, and metabolic stress. Besides cardiac cells, autophagy orchestrates the maturation of neutrophils and other immune cells, influencing their function. In this review, we will discuss the evidence supporting the role of autophagy in cardiac homeostasis, aging, and cardioimmunological response to cardiac injury. Finally, we highlight possible translational perspectives of modulating autophagy for therapeutic purposes to improve the care of patients with acute and chronic cardiac disease.

Direct cardiac reprogramming: A new technology for cardiac repair

Cardiovascular disease is one of the leading causes of morbidity and mortality worldwide, with myocardial infarctions being amongst the deadliest manifestations. Reduced blood flow to the heart can result in the death of cardiac tissue, leaving affected patients susceptible to further complications and recurrent disease. Further, contemporary management typically involves a pharmacopeia to manage the metabolic conditions contributing to atherosclerotic and hypertensive heart disease, rather than regeneration of the damaged myocardium. With modern healthcare extending lifespan, a larger demographic will be at risk for heart disease, driving the need for novel therapeutics that surpass those currently available in efficacy. Transdifferentiation and cellular reprogramming have been looked to as potential methods for the treatment of diseases throughout the body. Specifically targeting the fibrotic cells in cardiac scar tissue as a source to be reprogrammed into induced cardiomyocytes remains an appealing option. This review aims to highlight the history of and advances in cardiac reprogramming and describe its translational potential as a treatment for cardiovascular disease.

Direct Reprogramming of Resident Non-Myocyte Cells and Its Potential for In Vivo Cardiac Regeneration

Cardiac diseases are the foremost cause of morbidity and mortality worldwide. The heart has limited regenerative potential; therefore, lost cardiac tissue cannot be replenished after cardiac injury. Conventional therapies are unable to restore functional cardiac tissue. In recent decades, much attention has been paid to regenerative medicine to overcome this issue. Direct reprogramming is a promising therapeutic approach in regenerative cardiac medicine that has the potential to provide in situ cardiac regeneration. It consists of direct cell fate conversion of one cell type into another, avoiding transition through an intermediary pluripotent state. In injured cardiac tissue, this strategy directs transdifferentiation of resident non-myocyte cells (NMCs) into mature functional cardiac cells that help to restore the native tissue. Over the years, developments in reprogramming methods have suggested that regulation of several intrinsic factors in NMCs can help to achieve in situ direct cardiac reprogramming. Among NMCs, endogenous cardiac fibroblasts have been studied for their potential to be directly reprogrammed into both induced cardiomyocytes and induced cardiac progenitor cells, while pericytes can transdifferentiate towards endothelial cells and smooth muscle cells. This strategy has been indicated to improve heart function and reduce fibrosis after cardiac injury in preclinical models. This review summarizes the recent updates and progress in direct cardiac reprogramming of resident NMCs for in situ cardiac regeneration.

Identification of molecular subtypes of ischaemic stroke based on immune-related genes and weighted co-expression network analysis

Immune system has been reported to play a key role in the development of ischaemic stroke (IS). Nevertheless, its exact immune-related mechanism has not yet been fully revealed. Gene expression data of IS and healthy control samples was downloaded from Gene Expression Omnibus database and differentially expressed genes (DEGs) was obtained. Immune-related genes (IRGs) data was downloaded from the ImmPort database. The molecular subtypes of IS were identified based on IRGs and weighted co-expression network analysis (WGCNA). 827 DEGs and 1142 IRGs were obtained in IS. Based on 1142 IRGs, 128 IS samples were clustered into two molecular subtypes: clusterA and clusterB. Based on the WGCNA, the authors found that the blue module had the highest correlation with IS. In the blue module, 90 genes were screened as candidate genes. The top 55 genes were selected as the central nodes according to gene degree in protein-protein interactions network of all genes in blue module. Through taking overlap, nine real hub genes were obtained that might distinguish between clusterA subtype and clusterB subtype of IS. The real hub genes (IL7R, ITK, SOD1, CD3D, LEF1, FBL, MAF, DNMT1, and SLAMF1) may be associated with molecular subtypes and immune regulation of IS.

Development of direct cardiac reprogramming for clinical applications

The incidence of cardiovascular diseases is increasing worldwide, and cardiac regenerative therapy has great potential as a new treatment strategy, especially for ischemic heart disease. Direct cardiac reprogramming is a promising new cardiac regenerative therapy that uses defined factors to induce transdifferentiation of endogenous cardiac fibroblasts (CFs) into induced cardiomyocyte-like cells (iCMs). In vivo reprogramming is expected to restore lost cardiac function without necessitating cardiac transplantation by converting endogenous CFs that exist abundantly in cardiac tissues directly into iCMs. Indeed, we and other groups have demonstrated that in vivo cardiac reprogramming improves cardiac contractile function and reduces scar area after acute myocardial infarction (MI). Recently, we demonstrated that in vivo cardiac reprogramming is an innovative cardiac regenerative therapy that not only regenerates the myocardium, but also reverses fibrosis by inducing the quiescence of pro-fibrotic fibroblasts, thereby improving heart failure in chronic MI. In this review, we summarize the recent progresses in in vivo cardiac reprogramming, and discuss its prospects for future clinical applications and the challenges of direct human reprogramming, which has been a longstanding issue.

Direct cardiac reprogramming: Toward the era of multi-omics analysis

Limited regenerative capacity of adult cardiomyocytes precludes heart repair and regeneration after cardiac injury. Direct cardiac reprograming that converts scar-forming cardiac fibroblasts (CFs) into functional induced-cardiomyocytes (iCMs) offers promising potential to restore heart structure and heart function. Significant advances have been achieved in iCM reprogramming using genetic and epigenetic regulators, small molecules, and delivery strategies. Recent researches on the heterogeneity and reprogramming trajectories elucidated novel mechanisms of iCM reprogramming at single cell level. Here, we review recent progress in iCM reprogramming with a focus on multi-omics (transcriptomic, epigenomic and proteomic) researches to investigate the cellular and molecular machinery governing cell fate conversion. We also highlight the future potential using multi-omics approaches to dissect iCMs conversion for clinal applications.

The heart of cardiac reprogramming: The cardiac fibroblasts

Cardiovascular disease is the leading cause of death worldwide, outpacing pulmonary disease, infectious disease, and all forms of cancer. Myocardial infarction (MI) dominates cardiovascular disease, contributing to four out of five cardiovascular related deaths. Following MI, patients suffer adverse and irreversible myocardial remodeling associated with cardiomyocyte loss and infiltration of fibrotic scar tissue. Current therapies following MI only mitigate the cardiac physiological decline rather than restore damaged myocardium function. Direct cardiac reprogramming is one strategy that has promise in repairing injured cardiac tissue by generating new, functional cardiomyocytes from cardiac fibroblasts (CFs). With the ectopic expression of transcription factors, microRNAs, and small molecules, CFs can be reprogrammed into cardiomyocyte-like cells (iCMs) that display molecular signatures, structures, and contraction abilities similar to endogenous cardiomyocytes. The in vivo induction of iCMs following MI leads to significant reduction in fibrotic cardiac remodeling and improved heart function, indicating reprogramming is a viable option for repairing damaged heart tissue. Recent work has illustrated different methods to understand the mechanisms driving reprogramming, in an effort to improve the efficiency of iCM generation and create an approach translational into clinic. This review will provide an overview of CFs and describe different in vivo reprogramming methods.

The role of Platinum(IV)-based antitumor drugs and the anticancer immune response in medicinal inorganic chemistry. A systematic review from 2017 to 2022

Platinum-based antitumor drugs have been used in many types of tumors due to its broad antitumor spectrum in clinic. Encouraged by the cisplatin's (CDDP) worldwide success in cancer chemotherapy, the research in platinum-based antitumor drugs has evolved from traditional platinum drug to multi-ligand and multifunctional platinum prodrugs over half a century. With the rapid development of metal drugs and the anticancer immune response, challenges and opportunities in platinum drug research have been shifted from traditional platinum-based drugs to platinum-based hybrids and the direction of development is tending toward photodynamic therapy, nano-delivery therapy, drug combination, targeted therapy, diagnostic therapy, immune-combination therapy and tumor stem cell therapy. In this review, we first exhaustively overviewed the role of platinum-based antitumor prodrugs and the anticancer immune response in medicinal inorganic chemistry based on the special nanomaterials, the modification of specific ligands, and the multiple functions obtained that are beneficial for tumor therapy in the last five years. We also categorized them according to drug potency and function. There hasn't been a comprehensive evaluation of precursor platinum drugs in prior articles. And a multifarious approach to distinguish and detail the variety of alterations of platinum-based precursors in various valence states also hasn't been summarized. In addition, this review points out the main problems at the interface of chemistry, biology, and medicine from their action mechanisms for current platinum drug development, and provides up-to-date potential strategies from drug design perspectives to circumvent those drawbacks. And a promising idea is also enlightened for researchers in the development and discovery of platinum prodrugs.

A review of protocols for human iPSC culture, cardiac differentiation, subtype-specification, maturation, and direct reprogramming

The methods for the culture and cardiomyocyte differentiation of human embryonic stem cells, and later human induced pluripotent stem cells (hiPSC), have moved from a complex and uncontrolled systems to simplified and relatively robust protocols, using the knowledge and cues gathered at each step. HiPSC-derived cardiomyocytes have proven to be a useful tool in human disease modelling, drug discovery, developmental biology, and regenerative medicine. In this protocol review, we will highlight the evolution of protocols associated with hPSC culture, cardiomyocyte differentiation, sub-type specification, and cardiomyocyte maturation. We also discuss protocols for somatic cell direct reprogramming to cardiomyocyte-like cells.

p63 silencing induces epigenetic modulation to enhance human cardiac fibroblast to cardiomyocyte-like differentiation

Direct cell reprogramming represents a promising new myocardial regeneration strategy involving in situ transdifferentiation of cardiac fibroblasts into induced cardiomyocytes. Adult human cells are relatively resistant to reprogramming, however, likely because of epigenetic restraints on reprogramming gene activation. We hypothesized that modulation of the epigenetic regulator gene p63 could improve the efficiency of human cell cardio-differentiation. qRT-PCR analysis demonstrated significantly increased expression of a panel of cardiomyocyte marker genes in neonatal rat and adult rat and human cardiac fibroblasts treated with p63 shRNA (shp63) and the cardio-differentiation factors Hand2/Myocardin (H/M) versus treatment with Gata4, Mef2c and Tbx5 (GMT) with or without shp63 (p < 0.001). FACS analysis demonstrated that shp63+ H/M treatment of human cardiac fibroblasts significantly increased the percentage of cells expressing the cardiomyocyte marker cTnT compared to GMT treatment with or without shp63 (14.8% ± 1.4% versus 4.3% ± 1.1% and 3.1% ± 0.98%, respectively; p < 0.001). We further demonstrated that overexpression of the p63-transactivation inhibitory domain (TID) interferes with the physical interaction of p63 with the epigenetic regulator HDAC1 and that human cardiac fibroblasts treated with p63-TID+ H/M demonstrate increased cardiomyocyte marker gene expression compared to cells treated with shp63+ H/M (p < 0.05). Whereas human cardiac fibroblasts treated with GMT alone failed to contract in co-culture experiments, human cardiac fibroblasts treated with shp63+ HM or p63-TID+ H/M demonstrated calcium transients upon electrical stimulation and contractility synchronous with surrounding neonatal cardiomyocytes. These findings demonstrate that p63 silencing provides enhanced rat and human cardiac fibroblast transdifferentiation into induced cardiomyocytes compared to a standard reprogramming strategy. p63-TID overexpression may be a useful reprogramming strategy for overcoming epigenetic barriers to human fibroblast cardio-differentiation.

Direct cardiac reprogramming comes of age: Recent advance and remaining challenges

The adult human heart has limited regenerative capacity. As such, the massive cardiomyocyte loss due to myocardial infarction leads to scar formation and adverse cardiac remodeling, which ultimately results in chronic heart failure. Direct cardiac reprogramming that converts cardiac fibroblast into functional cardiomyocyte-like cells (also called iCMs) holds great promise for heart regeneration. Cardiac reprogramming has been achieved both in vitro and in vivo by using a variety of cocktails that comprise transcription factors, microRNAs, or small molecules. During the past several years, great progress has been made in improving reprogramming efficiency and understanding the underlying molecular mechanisms. Here, we summarize the direct cardiac reprogramming methods, review the current advances in understanding the molecular mechanisms of cardiac reprogramming, and highlight the novel insights gained from single-cell omics studies. Finally, we discuss the remaining challenges and future directions for the field.

Direct reprogramming as a route to cardiac repair

Ischemic heart disease is the leading cause of morbidity, mortality, and healthcare expenditure worldwide due to an inability of the heart to regenerate following injury. Thus, novel heart failure therapies aimed at promoting cardiomyocyte regeneration are desperately needed. In recent years, direct reprogramming of resident cardiac fibroblasts to induced cardiac-like myocytes (iCMs) has emerged as a promising therapeutic strategy to repurpose the fibrotic response of the injured heart toward a functional myocardium. Direct cardiac reprogramming was initially achieved through the overexpression of the transcription factors (TFs) Gata4, Mef2c, and Tbx5 (GMT). However, this combination of TFs and other subsequent cocktails demonstrated limited success in reprogramming adult human and mouse fibroblasts, constraining the clinical translation of this therapy. Over the past decade, significant effort has been dedicated to optimizing reprogramming cocktails comprised of cardiac TFs, epigenetic factors, microRNAs, or small molecules to yield efficient cardiac cell fate conversion. Yet, efficient reprogramming of adult human fibroblasts remains a significant challenge. Underlying mechanisms identified to accelerate this process have been centered on epigenetic remodeling at cardiac gene regulatory regions. Further studies to achieve a refined understanding and directed means of overcoming epigenetic barriers are merited to more rapidly translate these promising therapies to the clinic.

A Balance Between Autophagy and Other Cell Death Modalities in Cancer

Autophagy is an intracellular self-digestive process involved in catabolic degradation of damaged proteins, and organelles, and the elimination of cellular pathogens. Initially, autophagy was considered as a prosurvival mechanism, but the following insights shed light on its prodeath function. Nowadays, autophagy is established as a crucial player in the development of various diseases through interaction with other molecular pathways within a cell. Additionally, disturbance in autophagy is one of the main pathological alterations that lead to resistance of cancer cells to treatment. These autophagy-related pathologies gave rise to the development of new therapeutic drugs. Here, we summarize the current knowledge on the autophagic role in disease pathogenesis, particularly in cancer, and the interplay between autophagy and other cell death modalities in order to combat cancer.

Resuscitating the Field of Cardiac Regeneration: Seeking Answers from Basic Biology

Heart failure (HF) is one of the leading causes for hospital admissions worldwide. HF patients are classified based on the chronic changes in left ventricular ejection fraction (LVEF) as preserved (LVEF ≥ 50%), reduced (LVEF ≤ 40%), or mid-ranged (40% < LVEF < 50%) HFs. Treatments nowadays can prevent HFrEF progress, whereas only a few of the treatments have been proven to be effective in improving the survival of HFpEF. In this review, numerous mediators involved in the pathogenesis of HF are summarized. The regional upstream signaling and their diagnostic and therapeutic potential are also discussed. Additionally, the recent challenges and development in cardiac regenerative therapy that hold opportunities for future research and clinical translation are discussed.

Hippo Pathway Effector Tead1 Induces Cardiac Fibroblast to Cardiomyocyte Reprogramming

Background

The conversion of fibroblasts into induced cardiomyocytes may regenerate myocardial tissue from cardiac scar through in situ cell transdifferentiation. The efficiency transdifferentiation is low, especially for human cells. We explored the leveraging of Hippo pathway intermediates to enhance induced cardiomyocyte generation.

Methods and Results

We screened Hippo effectors Yap (yes‐associated protein), Taz (transcriptional activator binding domain), and Tead1 (TEA domain transcription factor 1; Td) for their reprogramming efficacy with cardio‐differentiating factors Gata4, Mef2C, and Tbx5 (GMT). Td induced nearly 3‐fold increased expression of cardiomyocyte marker cTnT (cardiac troponin T) by mouse embryonic and adult rat fibroblasts versus GMT administration alone (P<0.0001), while Yap and Taz failed to enhance cTnT expression. Serial substitution demonstrated that Td replacement of TBX5 induced the greatest cTnT expression enhancement and sarcomere organization in rat fibroblasts treated with all GMT substitutions (GMTd versus GMT: 17±1.2% versus 5.4±0.3%, P<0.0001). Cell contractility (beating) was seen in 6% of GMTd‐treated cells by 4 weeks after treatment, whereas no beating GMT‐treated cells were observed. Human cardiac fibroblasts likewise demonstrated increased cTnT expression with GMTd versus GMT treatment (7.5±0.3% versus 3.0±0.3%, P<0.01). Mechanistically, GMTd administration increased expression of the trimethylated lysine 4 of histone 3 (H3K4me3) mark at the promoter regions of cardio‐differentiation genes and mitochondrial biogenesis regulator genes in rat and human fibroblast, compared with GMT.

Conclusions

These data suggest that the Hippo pathway intermediate Tead1 is an important regulator of cardiac reprogramming that increases the efficiency of maturate induced cardiomyocytes generation and may be a vital component of human cardiodifferentiation strategies.

Association of DNA methylation and transcriptome reveals epigenetic etiology of heart failure

Epigenetic modifications viz. DNA methylation, histone modifications, and RNA-based alterations play a crucial role in the development of cardiovascular diseases. In this study, we investigated DNA methylation with an aim to reveal the epigenetic etiology of heart failure. Sprague-Dawley rats surviving myocardial infarction developed acute heart failure in 1 week. Genomic DNA methylation changes were profiled by bisulfite sequencing, and gene expression levels were analyzed by RNA-seq in failing and sham-operation hearts. A total of 3480 differentially methylated genes in the promoter regions including transcriptional start site and 1934 transcriptome-altered genes were identified in the defected hearts. Common differential genes were enriched by the gene ontology, Kyoto Encyclopedia of Genes and Genomes pathway, and protein-protein interaction for HF phenotypes. Among these, Mettl11b, HDAC3, HDAC11, ubiquitination-related genes, and snoRNAs are new epigenetic classifiers that had not been reported yet, which may be important regulators in HF.

Advanced Technologies to Target Cardiac Cell Fate Plasticity for Heart Regeneration

The adult human heart can only adapt to heart diseases by starting a myocardial remodeling process to compensate for the loss of functional cardiomyocytes, which ultimately develop into heart failure. In recent decades, the evolution of new strategies to regenerate the injured myocardium based on cellular reprogramming represents a revolutionary new paradigm for cardiac repair by targeting some key signaling molecules governing cardiac cell fate plasticity. While the indirect reprogramming routes require an in vitro engineered 3D tissue to be transplanted in vivo, the direct cardiac reprogramming would allow the administration of reprogramming factors directly in situ, thus holding great potential as in vivo treatment for clinical applications. In this framework, cellular reprogramming in partnership with nanotechnologies and bioengineering will offer new perspectives in the field of cardiovascular research for disease modeling, drug screening, and tissue engineering applications. In this review, we will summarize the recent progress in developing innovative therapeutic strategies based on manipulating cardiac cell fate plasticity in combination with bioengineering and nanotechnology-based approaches for targeting the failing heart.

Cardiac regeneration by direct reprogramming in this decade and beyond

Japan faces an increasing incidence of heart disease, owing to a shift towards a westernized lifestyle and an aging demographic. In cases where conventional interventions are not appropriate, regenerative medicine offers a promising therapeutic option. However, the use of stem cells has limitations, and therefore, “direct cardiac reprogramming” is emerging as an alternative treatment. Myocardial regeneration transdifferentiates cardiac fibroblasts into cardiomyocytes in situ.

Three cardiogenic transcription factors: Gata4, Mef2c, and Tbx5 (GMT) can induce direct reprogramming of fibroblasts into induced cardiomyocytes (iCMs), in mice. However, in humans, additional factors, such as Mesp1 and Myocd, are required. Inflammation and immune responses hinder the reprogramming process in mice, and epigenetic modifiers such as TET1 are involved in direct cardiac reprogramming in humans. The three main approaches to improving reprogramming efficiency are (1) improving direct cardiac reprogramming factors, (2) improving cell culture conditions, and (3) regulating epigenetic factors. miR-133 is a potential candidate for the first approach. For the second approach, inhibitors of TGF-β and Wnt signals, Akt1 overexpression, Notch signaling pathway inhibitors, such as DAPT ((S)-tert-butyl 2-((S)-2-(2-(3,5-difluorophenyl) acetamido) propanamido)-2-phenylacetate), fibroblast growth factor (FGF)-2, FGF-10, and vascular endothelial growth factor (VEGF: FFV) can influence reprogramming. Reducing the expression of Bmi1, which regulates the mono-ubiquitination of histone H2A, alters histone modification, and subsequently the reprogramming efficiency, in the third approach. In addition, diclofenac, a non-steroidal anti-inflammatory drug, and high level of Mef2c overexpression could improve direct cardiac reprogramming.

Direct cardiac reprogramming needs improvement if it is to be used in humans, and the molecular mechanisms involved remain largely elusive. Further advances in cardiac reprogramming research are needed to bring us closer to cardiac regenerative therapy.

In vivo reprogramming as a new approach to cardiac regenerative therapy

Cardiovascular diseases are a common cause of death worldwide. Adult cardiomyocytes have limited regenerative capacity after injury, and there is growing interest in cardiac regeneration as a new therapeutic strategy. There are several limitations of induced pluripotent stem cell-based transplantation therapy with respect to efficiency and risks of tumorigenesis. Direct reprogramming enables the conversion of terminally differentiated cells into target cell types using defined factors. In most cardiac diseases, activated fibroblasts proliferate in the damaged heart and contribute to the progression of heart failure. In vivo cardiac reprogramming, in which resident cardiac fibroblasts are converted into cardiomyocytes in situ, is expected to become a new cardiac regenerative therapy. Indeed, we and other groups have demonstrated that in vivo reprogramming improves cardiac function and reduces fibrosis after myocardial infarction. In this review, we summarize recent discoveries and developments related to in vivo reprogramming. In addition, issues that need to be resolved for clinical application are described.

Correlation of autophagy-related genes for predicting clinical prognosis in colorectal cancer

Aim: Autophagy plays a controversial role in cancer. The role of autophagy-related genes (ARGs) in colorectal cancer (CRC) was evaluated based on publicly available data from The Cancer Genome Atlas and the Human Autophagy Database. Materials & methods: After collecting CRC-related transcript and clinical data and a list of ARGs from public databases, the Wilcoxon test was used to identify the differentially expressed ARGs between CRC and paired normal tissues. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were used to identify the major biological properties and pathways associated with these genes. Univariate Cox regression was used to identify the prognosis-associated ARGs, and a forest plot was used to visualize the results. Kaplan-Meier analysis of the 5-year survival rate was performed. Univariate and multivariate Cox analyses were used to verify the impact of the prognosis-associated ARGs. Results: A total of 36 differentially expressed genes (16 upregulated and 20 downregulated in CRC) were obtained from among 206 ARGs. There were 53 enriched pathways, including the p53 signaling pathway, platinum drug resistance, apoptosis, EGFR tyrosine kinase inhibitor resistance and ErbB signaling pathway (p- and q-values <0.05). Kaplan-Meier analysis showed that the 5-year survival rate was 46.0% (95% CI: 0.335-0.631) and 76.0% (95% CI: 0.651-0.886) in the high- and low-risk groups, respectively. The high-risk patients had worse survival probability (p = 6.256 × 10^-5). Independent-samples t-tests revealed that MAP1LC3C expression was higher in patients aged ≤65 than >65 (p = 0.022); RAB7A expression was higher in patients aged ≤65 than >65 (p = 7.31 × 10^-4), higher in M1 than M0 (p = 0.042), higher in N1-3 than N0 (p = 0.002) and higher in stage III and IV than I and II (p = 0.042); risk score was higher in N1-3 than N0 (p = 0.001) and in stage III and IV than I and II (p = 0.002); and WIPI2 expression was higher in M1 than M0 (p = 0.002), higher in N1-3 than N0 (p = 2.059 × 10^-7) and higher in stage III and IV than I and II (p = 2.299 × 10^-7). There were no differences in risk score between males and females (p = 0.593), T1-2 and T3-4 (p = 0.082) or M0 and M1 (p = 0.072). Univariate and multivariate Cox analyses showed that RAB7A was a lower-risk gene, while MAP1LC3C, WIPI2, DAPK1, ULK3 and PELP1 were high-risk genes. Conclusion: Certain ARGs are potential prognostic molecular markers of poor prognosis in CRC. Additionally, the p53 signaling pathway, platinum drug resistance, apoptosis, EGFR tyrosine kinase inhibitor resistance and ErbB signaling pathway may be critical pathways regulated by ARGs in CRC.

The role of autophagy in cardiovascular pathology

Macroautophagy/autophagy is a conserved catabolic recycling pathway in which cytoplasmic components are sequestered, degraded, and recycled to survive various stress conditions. Autophagy dysregulation has been observed and linked with the development and progression of several pathologies, including cardiovascular diseases, the leading cause of death in the developed world. In this review, we aim to provide a broad understanding of the different molecular factors that govern autophagy regulation and how these mechanisms are involved in the development of specific cardiovascular pathologies, including ischemic and reperfusion injury, myocardial infarction, cardiac hypertrophy, cardiac remodeling, and heart failure.

Cardiac Regeneration: New Insights Into the Frontier of Ischemic Heart Failure Therapy

Ischemic heart disease is the leading cause of morbidity and mortality in the world. While pharmacological and surgical interventions developed in the late twentieth century drastically improved patient outcomes, mortality rates over the last two decades have begun to plateau. Following ischemic injury, pathological remodeling leads to cardiomyocyte loss and fibrosis leading to impaired heart function. Cardiomyocyte turnover rate in the adult heart is limited, and no clinical therapies currently exist to regenerate cardiomyocytes lost following ischemic injury. In this review, we summarize the progress of therapeutic strategies including revascularization and cell-based interventions to regenerate the heart: transiently inducing cardiomyocyte proliferation and direct reprogramming of fibroblasts into cardiomyocytes. Moreover, we highlight recent mechanistic insights governing these strategies to promote heart regeneration and identify current challenges in translating these approaches to human patients.