Direct in vivo reprogramming with non-viral sequential targeting nanoparticles promotes cardiac regeneration

Exposure to serum from exclusive heated tobacco product smokers induces mTOR activation and fibrotic features in human cardiac stromal cells

Chronic smokers have increased risk of fibrosis-related atrial fibrillation. The use of heated-tobacco products (HTPs) is increasing exponentially, and their health impact is still uncertain. We aim to investigate the effects of circulating molecules in exclusive HTP chronic smokers on the fibrotic behavior of human atrial cardiac stromal cells (CSCs). CSCs were isolated from atrial tissue of elective cardiac surgery patients, and exposed to serum lots from young healthy subjects, stratified in exclusive HTP smokers, tobacco combustion cigarette (TCC) smokers, or nonsmokers (NS). CSCs treated with TCC serum displayed impaired migration and increased expression of pro-inflammatory cytokines. Cells cultured with HTP serum showed increased levels of pro-fibrotic markers, and reduced expression of connexin-43. Both TCC and HTP sera increased collagen release and reduced secretion of angiogenic protective factors from CSCs, compared to NS serum. Paracrine support to tube-formation by endothelial cells and to viability of cardiomyocytes was significantly impaired. Treatment with sera of both smokers groups impaired H2O2/NO release balance by CSCs and reduced early phosphorylation of several pathways compared to NS serum, leading to mTOR activation. Cotreatment with rapamycin was able to reduce mTOR phosphorylation and differentiation into aSMA-positive myofibroblasts in CSCs exposed to TCC and HTP sera. In conclusion, the circulating molecules in the serum of chronic exclusive HTP smokers induce fibrotic behavior in CSCs through activation of the mTOR pathway, and reduce their beneficial paracrine effects on endothelial cells and cardiomyocytes. These results point to a potential risk for cardiac fibrosis in chronic HTP users.

Nanomedicine: A great boon for cardiac regenerative medicine

Cardiovascular disease (CVD) represents a significant global health challenge, remaining the leading cause of illness and mortality worldwide. The adult heart's limited regenerative capacity poses a major obstacle in repairing extensive damage caused by conditions like myocardial infarction. In response to these challenges, nanomedicine has emerged as a promising field aimed at improving treatment outcomes through innovative drug delivery strategies. Nanocarriers, such as nanoparticles (NPs), offer a revolutionary approach by facilitating targeted delivery of therapeutic agents directly to the heart. This precise delivery system holds immense potential for treating various cardiac conditions by addressing underlying mechanisms such as inflammation, oxidative stress, cell death, extracellular matrix remodeling, prosurvival signaling, and angiogenic pathways associated with ischemia-reperfusion injury. In this review, we provide a concise summary of the fundamental mechanisms involved in cardiac remodeling and regeneration. We explore how nanoparticle-based drug delivery systems can effectively target the afore-mentioned mechanisms. Furthermore, we discuss clinical trials that have utilized nanoparticle-based drug delivery systems specifically designed for cardiac applications. These trials demonstrate the potential of nanomedicine in clinical settings, paving the way for future advancements in cardiac therapeutics through precise and efficient drug delivery. Overall, nanomedicine holds promise in revolutionizing the treatment landscape of cardiovascular diseases by offering targeted and effective therapeutic strategies that address the complex pathophysiology of cardiac injuries.

Biomimetic nanoplatform treats myocardial ischemia/reperfusion injury by synergistically promoting angiogenesis and inhibiting inflammation

After myocardial ischemia/reperfusion injury (MI/RI), endothelial cell injury causes impaired angiogenesis and obstruction of microcirculation, resulting in an inflammatory outburst that exacerbates the damage. Therefore, synergistic blood vessel repair and inflammation inhibition are effective therapeutic strategies. In this study, we developed a platelet membrane (PM)-encapsulated baicalin nanocrystalline (BA NC) nanoplatform with a high drug load, BA NC@PM, which co-target to endothelial cells and macrophages through the transmembrane proteins of the PM to promote angiogenesis and achieve anti-inflammatory effects. In vitro cell scratch assays and transwell assay manifested that BA NC@PM could promote endothelial cell migration, as well as increase mRNA expression of CD31 and VEGF in the heart after treatment of MI/RI mice, suggesting its favorable vascular repair function. In addition, the preparation significantly reduced the expression of pro-inflammatory factors and increased the expression of anti-inflammatory factors in plasma, promoting the polarization of macrophages. Our study highlights a strategy for enhancing the treatment of MI/RI by promoting angiogenesis and regulating macrophage polarization via the biomimetic BA NC@PM nanoplatform.

Acid Neutralization by Composite Lysine Nanoparticles for Spinal Cord Injury Recovery through Mitigating Mitochondrial Dysfunction

After spinal cord injury (SCI), significant alterations in the tissue microenvironment lead to mitochondrial dysfunction, inducing apoptosis and inhibiting the remodeling of neural circuits, thereby impeding recovery. Although previous studies have demonstrated a marked decrease in pH at the injury site, creating an acidic microenvironment, the impact of improving this acidic microenvironment on SCI recovery has not been investigated. This study prepared a lysine@hollow mesoporous silica nanoparticle/gelatin methacrylate (GelMA) (L@H/G) composite hydrogel. The L@H/G composite hydrogel was demonstrated to release lysine and efficiently improve the acidic microenvironment slowly. Significantly, the composite hydrogel reduced cell apoptosis, promoted nerve regeneration, inhibited glial scar formation, and ultimately enhanced motor function recovery in mice with SCI. Mechanistically, the L@H/G hydrogel improved the mitochondrial tricarboxylic acid (TCA) cycle and fatty acid metabolism, restoring energy supply and facilitating mitochondrial function recovery. To the best of our knowledge, this is the first report confirming that improving the acidic microenvironment could promote SCI repair, providing a potential therapeutic strategy for SCI.

Biomimetic Nano-Degrader Based CD47-SIRPα Immune Checkpoint Inhibition Promotes Macrophage Efferocytosis for Cardiac Repair

CD47-SIRPα axis is an immunotherapeutic target in tumor therapy. However, current monoclonal antibody targeting CD47-SIRPα axis is associated with on-target off-tumor and antigen sink effects, which significantly limit its potential clinical application. Herein, a biomimetic nano-degrader is developed to inhibit CD47-SIRPα axis in a site-specific manner through SIRPα degradation, and its efficacy in acute myocardial infarction (AMI) is evaluated. The nano-degrader is constructed by hybridizing liposome with red blood cell (RBC) membrane (RLP), which mimics the CD47 density of senescent RBCs and possesses a natural high-affinity binding capability to SIRPα on macrophages without signaling capacity. RLP would bind with SIRPα and induce its lysosomal degradation through receptor-mediated endocytosis. To enhance its tissue specificity, Ly6G antibody conjugation (aRLP) is applied, enabling its attachment to neutrophils and accumulation within inflammatory sites. In the myocardial infarction model, aRLP accumulated in the infarcted myocardium blocks CD47-SIRPα axis and subsequently promoted the efferocytosis of apoptotic cardiomyocytes by macrophage, improved heart repair. This nano-degrader efficiently degraded SIRPα in lysosomes, providing a new strategy for immunotherapy with great clinical transformation potential.

Nanotechnology-based non-viral vectors for gene delivery in cardiovascular diseases

Gene therapy is a technique that rectifies defective or abnormal genes by introducing exogenous genes into target cells to cure the disease. Although gene therapy has gained some accomplishment for the diagnosis and therapy of inherited or acquired cardiovascular diseases, how to efficiently and specifically deliver targeted genes to the lesion sites without being cleared by the blood system remains challenging. Based on nanotechnology development, the non-viral vectors provide a promising strategy for overcoming the difficulties in gene therapy. At present, according to the physicochemical properties, nanotechnology-based non-viral vectors include polymers, liposomes, lipid nanoparticles, and inorganic nanoparticles. Non-viral vectors have an advantage in safety, efficiency, and easy production, possessing potential clinical application value when compared with viral vectors. Therefore, we summarized recent research progress of gene therapy for cardiovascular diseases based on commonly used non-viral vectors, hopefully providing guidance and orientation for future relevant research.

Direct cellular reprogramming techniques for cardiovascular regenerative therapeutics

Cardiovascular diseases remain a leading cause of hospitalization affecting approximately 38 million people worldwide. While pharmacological and revascularization techniques can improve the patient's survival and quality of life, they cannot help reversing myocardial infarction injury and heart failure. Direct reprogramming of somatic cells to cardiomyocyte and cardiac progenitor cells offers a new approach to cellular reprogramming and paves the way for translational regenerative medicine. Direct reprogramming can bypass the pluripotent stage with the potential advantage of non-immunogenic cell products, reduced carcinogenic risk, and no requirement for embryonic tissue. The process of directly reprogramming cardiac cells was first achieved through the overexpression of transcription factors such as GATA4, MEF2C, and TBX5. However, over the past decade, significant work has been focused on enhancing direct reprogramming using a mixture of transcription factors, microRNAs, and small molecules to achieve cardiac cell fate. This review discusses the evolution of direct reprogramming, recent progress in achieving efficient cardiac cell fate conversion, and describes the reprogramming mechanisms at a molecular level. We also explore various viral and non-viral delivery methods currently being used to aid in the delivery of reprogramming factors to improve efficiency. However, further studies will be needed to overcome molecular and epigenetic barriers to successfully achieve translational cardiac regenerative therapeutics.

Bioactive materials for in vivo sweat gland regeneration

Loss of sweat glands (SwGs) commonly associated with extensive skin defects is a leading cause of hyperthermia and heat stroke. In vivo tissue engineering possesses the potential to take use of the body natural ability to regenerate SwGs, making it more conducive to clinical translation. Despite recent advances in regenerative medicine, reconstructing SwG tissue with the same structure and function as native tissue remains challenging. Elucidating the SwG generation mechanism and developing biomaterials for in vivo tissue engineering is essential for understanding and developing in vivo SwG regenerative strategies. Here, we outline the cell biology associated with functional wound healing and the characteristics of bioactive materials. We critically summarize the recent progress in bioactive material-based cell modulation approaches for in vivo SwG regeneration, including the recruitment of endogenous cells to the skin lesion for SwG regeneration and in vivo cellular reprogramming for SwG regeneration. We discussed the re-establishment of microenvironment via bioactive material-mediated regulators. Besides, we offer promising perspectives for directing in situ SwG regeneration via bioactive material-based cell-free strategy, which is a simple and effective approach to regenerate SwG tissue with both fidelity of structure and function. Finally, we discuss the opportunities and challenges of in vivo SwG regeneration in detail. The molecular mechanisms and cell fate modulation of in vivo SwG regeneration will provide further insights into the regeneration of patient-specific SwGs and the development of potential intervention strategies for gland-derived diseases.

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.

Nanocarrier-Mediated Delivery of MicroRNAs for Fibrotic Diseases

MicroRNAs (miRNAs) are endogenous noncoding RNAs that mediate the fibrotic process by regulating multiple targets. MicroRNA-based therapy can restore or inhibit miRNA expression and is expected to become an effective approach to prevent and alleviate fibrotic diseases. However, the safe, targeted, and effective delivery of miRNAs is a major challenge in translating miRNA therapy from bench to bedside. In this review, we briefly describe the pathophysiological process of fibrosis and the mechanism by which miRNAs regulate the progression of fibrosis. Additionally, we summarize the miRNA nanodelivery tools for fibrotic diseases, including chemical modifications and polymer-based, lipid-based, and exosome-based delivery systems. Further clarification of the role of miRNAs in fibrosis and the development of a novel nanodelivery system may facilitate the prevention and alleviation of fibrotic diseases in the future.

Precision cardiac targeting: empowering curcumin therapy through smart exosome-mediated drug delivery in myocardial infarction

Nanoparticle-mediated drug delivery has emerged as a highly promising and effective therapeutic approach for addressing myocardial infarction. However, clinical translation tends to be a failure due to low cardiac retention as well as liver and spleen entrapment in previous therapies. Herein, we report a two-step exosome delivery system, which precludes internalization by the mononuclear phagocyte system before the delivery of therapeutic cardiac targeting exosomes (ExoCTP). Importantly, curcumin released by ExoCTP diminishes reactive oxygen species over-accumulation in ischemic myocardium, as well as serum levels of lactate dehydrogenase, malonyldialdehyde, superoxide dismutase and glutathione, indicating better antioxidant capacity than free curcumin. Finally, our strategy was proven to greatly potentiate the delivery and therapeutic efficacy of curcumin without systemic toxicity. Taken together, our smart exosome-mediated drug delivery strategy can serve either as therapeutics alone or in combination with other drugs for effective heart targeting and subsequent wound healing.

Nanocarriers for gene delivery to the cardiovascular system

Cardiovascular diseases have posed a great threat to human health. Fortunately, gene therapy holds great promise in the fight against cardiovascular disease (CVD). In gene therapy, it is necessary to select the appropriate carriers to deliver the genes to the target cells of the target organs. There are usually two types of carriers, viral carriers and non-viral carriers. However, problems such as high immunogenicity, inflammatory response, and limited loading capacity have arisen with the use of viral carriers. Therefore, scholars turned their attention to non-viral carriers. Among them, nanocarriers are highly valued because of their easy modification, targeting, and low toxicity. Despite the many successes of gene therapy in the treatment of human diseases, it is worth noting that there are still many problems to be solved in the field of gene therapy for the treatment of cardiovascular diseases. In this review, we give a brief introduction to the common nanocarriers and several common cardiovascular diseases (arteriosclerosis, myocardial infarction, myocardial hypertrophy). On this basis, the application of gene delivery nanocarriers in the treatment of these diseases is introduced in detail.

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.

Biomimetic nanoparticles loaded lutein functionalized by macrophage membrane for targeted amelioration pressure overload-induced cardiac fibrosis

Lutein is a strong antioxidant with anti-inflammatory, anti-oxidative and cardioprotective effects and could be a promising candidate for the treatment of hypertensive heart disease (HHD), but is not clinically appealing because of its low oral bioavailability and main distribution in the eyes. To address this, a biomimetic drug delivery system-MMLNPs was established by coating macrophage membranes (MMs) onto lutein-loaded poly (lactic-co-glycolic acid) (PLGA) nanoparticles (LNPs). This study characterized the physical properties of biomimetic nanoparticles and examined the targeting capability, therapeutic effects and mechanism, and biosecurity of administering them for cardiac fibrosis therapy in the transverse aortic constriction (TAC) model and in vitro. Transmission electron microscope mapping and dynamic light scattering analysis proved that MMLNPs were spherical nanoparticles camouflaged by a layer of cell membrane and had negative zeta potential. Confocal laser scanning microscopy and flow cytometry analysis showed that MMs on the biomimetic nanoparticles hindered the phagocytosis of macrophages and facilitated the targeting of activated endothelial cells. Ex vivo fluorescence imaging experiments demonstrated the targeting of biomimetic nanoparticles to the injured heart. EdU assay indicated that MMLNPs have the same potential to inhibit angiotensin (Ang) II-induced cardiac fibroblast proliferation as free lutein. Furthermore, echocardiography showed that MMLNPs improved cardiac function and structure, and Masson staining and western blotting showed that MMLNPs ameliorated cardiac fibrosis. We found MMLNPs inhibited the interleukin (IL)-11/ERK signaling pathway which was up-regulated in the TAC model compared to the sham-operated mouse. Biochemical testing and hematoxylin and eosin staining proved that the long-term use of MMLNPs lacked biological toxicity. Collectively, MMLNPs might be a promising nanodrug delivery approach to attenuate pressure overload (PO)-induced cardiac fibrosis.

Nanotechnology in coronary heart disease

Coronary heart disease (CHD) is one of the major causes of death and disability worldwide, especially in low- and middle-income countries and among older populations. Conventional diagnostic and therapeutic approaches have limitations such as low sensitivity, high cost and side effects. Nanotechnology offers promising alternative strategies for the diagnosis and treatment of CHD by exploiting the unique properties of nanomaterials. In this review, we use bibliometric analysis to identify research hotspots in the application of nanotechnology in CHD and provide a comprehensive overview of the current state of the art. Nanomaterials with enhanced imaging and biosensing capabilities can improve the early detection of CHD through advanced contrast agents and high-resolution imaging techniques. Moreover, nanomaterials can facilitate targeted drug delivery, tissue engineering and modulation of inflammation and oxidative stress, thus addressing multiple aspects of CHD pathophysiology. We discuss the application of nanotechnology in CHD diagnosis (imaging and sensors) and treatment (regulation of macrophages, cardiac repair, anti-oxidative stress), and provide insights into future research directions and clinical translation. This review serves as a valuable resource for researchers and clinicians seeking to harness the potential of nanotechnology in the management of CHD. STATEMENT OF SIGNIFICANCE: Coronary heart disease (CHD) is the one of leading cause of death and disability worldwide. Nanotechnology offers new strategies for diagnosing and treating CHD by exploiting the unique properties of nanomaterials. This review uses bibliometric analysis to uncover research trends in the use of nanotechnology for CHD. We discuss the potential of nanomaterials for early CHD detection through advanced imaging and biosensing, targeted drug delivery, tissue engineering, and modulation of inflammation and oxidative stress. We also offer insights into future research directions and potential clinical applications. This work aims to guide researchers and clinicians in leveraging nanotechnology to improve CHD patient outcomes and quality of life.

Delivery of Therapeutic miRNA via Plasma-Polymerised Nanoparticles Rescues Diabetes-Impaired Endothelial Function

MicroRNAs (miRNAs) are increasingly recognised as key regulators of the development and progression of many diseases due to their ability to modulate gene expression post-translationally. While this makes them an attractive therapeutic target, clinical application of miRNA therapy remains at an early stage and in part is limited by the lack of effective delivery modalities. Here, we determined the feasibility of delivering miRNA using a new class of plasma-polymerised nanoparticles (PPNs), which we have recently isolated and characterised. We showed that PPN-miRNAs have no significant effect on endothelial cell viability in vitro in either normal media or in the presence of high-glucose conditions. Delivery of a miRNA inhibitor targeting miR-503 suppressed glucose-induced miR-503 upregulation and restored the downstream mRNA expression of CCNE1 and CDC25a in endothelial cells. Subsequently, PPN delivery of miR-503 inhibitors enhanced endothelial angiogenesis, including tubulogenesis and migration, in culture conditions that mimic diabetic ischemia. An intramuscular injection of a PPN-miR-503 inhibitor promoted blood-perfusion recovery in the hindlimb of diabetic mice following surgically induced ischemia, linked with an increase in new blood vessel formation. Together, this study demonstrates the effective use of PPN to deliver therapeutic miRNAs in the context of diabetes.

Gene Therapy Using Efficient Direct Lineage Reprogramming Technology for Neurological Diseases

Gene therapy is an innovative approach in the field of regenerative medicine. This therapy entails the transfer of genetic material into a patient's cells to treat diseases. In particular, gene therapy for neurological diseases has recently achieved significant progress, with numerous studies investigating the use of adeno-associated viruses for the targeted delivery of therapeutic genetic fragments. This approach has potential applications for treating incurable diseases, including paralysis and motor impairment caused by spinal cord injury and Parkinson's disease, and it is characterized by dopaminergic neuron degeneration. Recently, several studies have explored the potential of direct lineage reprogramming (DLR) for treating incurable diseases, and highlighted the advantages of DLR over conventional stem cell therapy. However, application of DLR technology in clinical practice is hindered by its low efficiency compared with cell therapy using stem cell differentiation. To overcome this limitation, researchers have explored various strategies such as the efficiency of DLR. In this study, we focused on innovative strategies, including the use of a nanoporous particle-based gene delivery system to improve the reprogramming efficiency of DLR-induced neurons. We believe that discussing these approaches can facilitate the development of more effective gene therapies for neurological disorders.

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.

Mapping research performance and hotspots on nanoparticles in cardiovascular diseases

Nanoparticles have broad prospects and profound academic significance in cardiovascular diseases. This study aimed to comprehensively summarize the global scientific achievements of nanoparticles in cardiovascular diseases research. Articles on the application of nanoparticles in cardiovascular diseases published from 2002 to 2021 were retrieved from the science citation index expanded of the Web of Science Core Collection, and knowledge maps were generated by Cite Space, VOS viewer, and Hist Cite for further bibliometric analysis. A total of 4321 records were retrieved, and only reviews and articles were retained with a total of 4258 studies. The number of publications on nanoparticles in the cardiovascular field has steadily increased from 2002 to 2021. China and the US contribute the most to this field, producing nearly all the most influential authors and institutions in the top 10 list. The Chinese Academy of Medical Sciences and Harvard University have obtained many high-quality research results. Targeted drug delivery via nanoparticles, myocardial infarction and atherosclerosis are research hotspots. This is the first time to analyze the application of nanoparticles in the cardiovascular field by using multiple bibliometric software. This study provides evidence for researchers to understand the hotspots and directions in this area.

Emerging technologies for cardiac tissue engineering and artificial hearts

Heart diseases, especially cardiovascular diseases, have brought heavy burden on society for their high morbidity and mortality. In clinical, heart transplantation is recognized as an effective strategy to rescue the lives of patients, while it may suffer from lack of donors and possible immune responses. In view of this, tremendous efforts have been devoted to developing alternative strategies to recover the function and promote the regeneration of cardiac tissues. As an emerging field blending cell biology and material science, tissue engineering technique allows the construction of biomimetic living complexes as organ substitutes for heart repair. In this review, we will present the recent progress in cardiac tissue engineering and artificial hearts. After introducing the critical elements in cardiac tissue engineering, we will present advanced fabrication methods to achieve scaffolds with desired micro/nanostructure design as well as the applications of these bioinspired scaffolds. We will also discuss the current dilemma and possible development direction from a biomedical perspective.

Cardiac regeneration: Options for repairing the injured heart

Cardiac regeneration is one of the grand challenges in repairing injured human hearts. Numerous studies of signaling pathways and metabolism on cardiac development and disease pave the way for endogenous cardiomyocyte regeneration. New drug delivery approaches, high-throughput screening, as well as novel therapeutic compounds combined with gene editing will facilitate the development of potential cell-free therapeutics. In parallel, progress has been made in the field of cell-based therapies. Transplantation of human pluripotent stem cell (hPSC)-derived cardiomyocytes (hPSC-CMs) can partially rescue the myocardial defects caused by cardiomyocyte loss in large animals. In this review, we summarize current cell-based and cell-free regenerative therapies, discuss the importance of cardiomyocyte maturation in cardiac regenerative medicine, and envision new ways of regeneration for the injured heart.

Can Extracellular Vesicles as Drug Delivery Systems Be a Game Changer in Cardiac Disease?

Cardiac diseases such as myocardial infarction and heart failure have been the leading cause of death worldwide for more than 20 years, and new treatments continue to be investigated. Heart transplantation, a curative treatment for severe cardiac dysfunction, is available to only a small number of patients due to the rarity of donors and high costs. Cardiac regenerative medicine using embryonic stem cells and induced pluripotent stem cells is expected to be a new alternative to heart transplantation, but it has problems such as induction of immune response, tumor formation, and low survival rate of transplanted cells. On the other hand, there has been a focus on cell-free therapy using extracellular vesicles (EVs) due to their high biocompatibility and target specificity. Exosomes, one type of EV, play a role in the molecular transport system in vivo and can be considered a drug delivery system (DDS) innate to all living things. Exosomes contain nucleic acids and proteins, which are transported from secretory cells to recipient cells. Molecules in exosomes are encapsulated in a lipid bilayer, which allows them to exist stably in body fluids without being affected by nuclease degradation enzymes. Therefore, the therapeutic use of exosomes as DDSs has been widely explored and is being used in clinical trials and other clinical settings. This review summarizes the current topics of EVs as DDSs in cardiac disease.

Advances in Cellular Reprogramming-Based Approaches for Heart Regenerative Repair

Continuous loss of cardiomyocytes (CMs) is one of the fundamental characteristics of many heart diseases, which eventually can lead to heart failure. Due to the limited proliferation ability of human adult CMs, treatment efficacy has been limited in terms of fully repairing damaged hearts. It has been shown that cell lineage conversion can be achieved by using cell reprogramming approaches, including human induced pluripotent stem cells (hiPSCs), providing a promising therapeutic for regenerative heart medicine. Recent studies using advanced cellular reprogramming-based techniques have also contributed some new strategies for regenerative heart repair. In this review, hiPSC-derived cell therapeutic methods are introduced, and the clinical setting challenges (maturation, engraftment, immune response, scalability, and tumorigenicity), with potential solutions, are discussed. Inspired by the iPSC reprogramming, the approaches of direct cell lineage conversion are merging, such as induced cardiomyocyte-like cells (iCMs) and induced cardiac progenitor cells (iCPCs) derived from fibroblasts, without induction of pluripotency. The studies of cellular and molecular pathways also reveal that epigenetic resetting is the essential mechanism of reprogramming and lineage conversion. Therefore, CRISPR techniques that can be repurposed for genomic or epigenetic editing become attractive approaches for cellular reprogramming. In addition, viral and non-viral delivery strategies that are utilized to achieve CM reprogramming will be introduced, and the therapeutic effects of iCMs or iCPCs on myocardial infarction will be compared. After the improvement of reprogramming efficiency by developing new techniques, reprogrammed iCPCs or iCMs will provide an alternative to hiPSC-based approaches for regenerative heart therapies, heart disease modeling, and new drug screening.

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.

Multifunctional biomaterial platforms for blocking the fibrosis process and promoting cellular restoring effects in myocardial fibrosis therapy

Myocardial fibrosis is the result of abnormal healing after acute and chronic myocardial damage and is a direct cause of heart failure and cardiac insufficiency. The clinical approach is to preserve cardiac function and inhibit fibrosis through surgery aimed at dredging blood vessels. However, this strategy does not adequately address the deterioration of fibrosis and cardiac function recovery. Therefore, numerous biomaterial platforms have been developed to address the above issues. In this review, we summarize the existing biomaterial delivery and restoring platforms, In addition, we also clarify the therapeutic strategies based on biomaterial platforms, including general strategies to block the fibrosis process and new strategies to promote cellular restoring effects. The development of structures with the ability to block further fibrosis progression as well as to promote cardiomyocytes viability should be the main research interests in myocardial fibrosis, and the reestablishment of structures necessary for normal cardiac function is central to the treatment of myocardial fibrosis. Finally, the future application of biomaterials for myocardial fibrosis is also highlighted.

Graphene Nanosheets Mediate Efficient Direct Reprogramming into Induced Cardiomyocytes

In vivo cardiac reprogramming is a potential therapeutic strategy to replace cardiomyocytes in patients with myocardial infarction. However, low conversion efficiency is a limitation of In vivo cardiac reprogramming for heart failure. In this study, we showed that graphene nanosheets mediated efficient direct reprogramming into induced cardiomyocytes In vivo. We observed that the administration of graphene nanosheets led to the accumulation of H3K4me3, which resulted in direct cardiac reprogramming. Importantly, the administration of graphene nanosheets combined with cardiac reprogramming factors in a mouse model of myocardial infarction enhanced the effectiveness of directly reprogrammed cell-based cardiac repair. Collectively, our findings suggest that graphene nanosheets can be used as an excellent biomaterial to promote cardiac cell fate conversion and provide a robust reprogramming platform for cardiac regeneration in ischemic heart disease.

Material Engineering in Gut Microbiome and Human Health

Tremendous progress has been made in the past decade regarding our understanding of the gut microbiome's role in human health. Currently, however, a comprehensive and focused review marrying the two distinct fields of gut microbiome and material research is lacking. To bridge the gap, the current paper discusses critical aspects of the rapidly emerging research topic of "material engineering in the gut microbiome and human health." By engaging scientists with diverse backgrounds in biomaterials, gut-microbiome axis, neuroscience, synthetic biology, tissue engineering, and biosensing in a dialogue, our goal is to accelerate the development of research tools for gut microbiome research and the development of therapeutics that target the gut microbiome. For this purpose, state-of-the-art knowledge is presented here on biomaterial technologies that facilitate the study, analysis, and manipulation of the gut microbiome, including intestinal organoids, gut-on-chip models, hydrogels for spatial mapping of gut microbiome compositions, microbiome biosensors, and oral bacteria delivery systems. In addition, a discussion is provided regarding the microbiome-gut-brain axis and the critical roles that biomaterials can play to investigate and regulate the axis. Lastly, perspectives are provided regarding future directions on how to develop and use novel biomaterials in gut microbiome research, as well as essential regulatory rules in clinical translation. In this way, we hope to inspire research into future biomaterial technologies to advance gut microbiome research and gut microbiome-based theragnostics.

Manipulating Cardiomyocyte Plasticity for Heart Regeneration

Pathological heart injuries such as myocardial infarction induce adverse ventricular remodeling and progression to heart failure owing to widespread cardiomyocyte death. The adult mammalian heart is terminally differentiated unlike those of lower vertebrates. Therefore, the proliferative capacity of adult cardiomyocytes is limited and insufficient to restore an injured heart. Although current therapeutic approaches can delay progressive remodeling and heart failure, difficulties with the direct replenishment of lost cardiomyocytes results in a poor long-term prognosis for patients with heart failure. However, it has been revealed that cardiac function can be improved by regulating the cell cycle or changing the cell state of cardiomyocytes by delivering specific genes or small molecules. Therefore, manipulation of cardiomyocyte plasticity can be an effective treatment for heart disease. This review summarizes the recent studies that control heart regeneration by manipulating cardiomyocyte plasticity with various approaches including differentiating pluripotent stem cells into cardiomyocytes, reprogramming cardiac fibroblasts into cardiomyocytes, and reactivating the proliferation of cardiomyocytes.

LSD1 regulates the expressions of core cardiogenic transcription factors and cardiac genes in oxygen and glucose deprivation injured mice fibroblasts in vitro

Cardiac reprogramming has emerged as a novel therapeutic approach to regenerating the damaged heart by directly converting endogenous cardiac fibroblasts (CFs) into induced cardiomyocytes (iCMs). Cardiac reprogramming requires the activation of the cardiogenic transcriptional program in concert with the repression of the fibroblastic transcriptional program. Lysine-specific demethylase 1 (LSD1) plays an instrumental role in many physiological processes such as cell growth, differentiation and metabolism. The epigenetic modifications of histones are essential for the accurate expression of genes in cardiomyocytes and the normal functioning of the heart. However, the effect of LSD1 in regulating the cardiogenic transcriptional program under myocardial ischemia/reperfusion (I/R) injury remains unclear. Thus, mice I/R injury was induced by 4 and 24 h reperfusion after 1-h occlusion of the left anterior descending coronary artery. The primary CFs and CMs were exposed under oxygen and glucose deprivation (OGD) to mimic I/R injury. The expression of LSD1 significantly decreased in I/R injured heart tissue and OGD-injured primary CFs and CM, and methylated histone presented a notable increase in OGD-injured primary CFs. Overexpression of LSD1 inhibited the injury of primary CFs induced by OGD, but showed limited inhibition on injured primary CMs. Under the OGD condition, LSD1 overexpression significantly increased cell viability, decreased cell apoptosis and reactive oxygen species (ROS) production of primary CFs. The expression of core cardiogenic transcription factors and cardiac genes were significantly decreased in OGD injured primary CFs, whereas LSD1 overexpression reversed the decrease of transcription factors and cardiac genes under the OGD condition. In conclusion, the overexpression of LSD1 has a protective role in I/R injury by inhibiting the histone methylation of primary CFs and regulates the expressions of core cardiogenic transcription factors and cardiac genes, which can prove to be a potential approach for direct cardiac reprogramming.

Designer Functional Nanomedicine for Myocardial Repair by Regulating the Inflammatory Microenvironment

Acute myocardial infarction is a major global health problem, and the repair of damaged myocardium is still a major challenge. Myocardial injury triggers an inflammatory response: immune cells infiltrate into the myocardium while activating myofibroblasts and vascular endothelial cells, promoting tissue repair and scar formation. Fragments released by cardiomyocytes become endogenous “danger signals”, which are recognized by cardiac pattern recognition receptors, activate resident cardiac immune cells, release thrombin factors and inflammatory mediators, and trigger severe inflammatory responses. Inflammatory signaling plays an important role in the dilation and fibrosis remodeling of the infarcted heart, and is a key event driving the pathogenesis of post-infarct heart failure. At present, there is no effective way to reverse the inflammatory microenvironment in injured myocardium, so it is urgent to find new therapeutic and diagnostic strategies. Nanomedicine, the application of nanoparticles for the prevention, treatment, and imaging of disease, has produced a number of promising applications. This review discusses the treatment and challenges of myocardial injury and describes the advantages of functional nanoparticles in regulating the myocardial inflammatory microenvironment and overcoming side effects. In addition, the role of inflammatory signals in regulating the repair and remodeling of infarcted hearts is discussed, and specific therapeutic targets are identified to provide new therapeutic ideas for the treatment of myocardial injury.

Small molecules facilitate single factor-mediated sweat gland cell reprogramming

BACKGROUND

Large skin defects severely disrupt the overall skin structure and can irreversibly damage sweat glands (SG), thus impairing the skin's physiological function. This study aims to develop a stepwise reprogramming strategy to convert fibroblasts into SG lineages, which may provide a promising method to obtain desirable cell types for the functional repair and regeneration of damaged skin.

METHODS

The expression of the SG markers cytokeratin 5 (CK5), cytokeratin 10 (CK10), cytokeratin 18 (CK18), carcino-embryonic antigen (CEA), aquaporin 5 (AQP5) and α-smooth muscle actin (α-SMA) was assessed with quantitative PCR (qPCR), immunofluorescence and flow cytometry. Calcium activity analysis was conducted to test the function of induced SG-like cells (iSGCs). Mouse xenograft models were also used to evaluate the in vivo regeneration of iSGCs. BALB/c nude mice were randomly divided into a normal group, SGM treatment group and iSGC transplantation group. Immunocytochemical analyses and starch-iodine sweat tests were used to confirm the in vivo regeneration of iSGCs.

RESULTS

EDA overexpression drove HDF conversion into iSGCs in SG culture medium (SGM). qPCR indicated significantly increased mRNA levels of the SG markers CK5, CK18 and CEA in iSGCs, and flow cytometry data demonstrated (4.18 ± 0.04)% of iSGCs were CK5 positive and (4.36 ± 0.25)% of iSGCs were CK18 positive. The addition of chemical cocktails greatly accelerated the SG fate program. qPCR results revealed significantly increased mRNA expression of CK5, CK18 and CEA in iSGCs, as well as activation of the duct marker CK10 and luminal functional marker AQP5. Flow cytometry indicated, after the treatment of chemical cocktails, (23.05 ± 2.49)% of iSGCs expressed CK5⁺ and (55.79 ± 3.18)% of iSGCs expressed CK18⁺, respectively. Calcium activity analysis indicated that the reactivity of iSGCs to acetylcholine was close to that of primary SG cells [(60.79 ± 7.71)% vs. (70.59 ± 0.34)%, ns]. In vivo transplantation experiments showed approximately (5.2 ± 1.1)% of the mice were sweat test positive, and the histological analysis results indicated that regenerated SG structures were present in iSGCs-treated mice.

CONCLUSION

We developed a SG reprogramming strategy to generate functional iSGCs from HDFs by using the single factor EDA in combination with SGM and small molecules. The generation of iSGCs has important implications for future in situ skin regeneration with SG restoration.

Nanoparticles Targeting the Molecular Pathways of Heart Remodeling and Regeneration

Cardiovascular diseases are the main cause of death worldwide, a trend that will continue to grow over the next decade. The heart consists of a complex cellular network based mainly on cardiomyocytes, but also on endothelial cells, smooth muscle cells, fibroblasts, and pericytes, which closely communicate through paracrine factors and direct contact. These interactions serve as valuable targets in understanding the phenomenon of heart remodeling and regeneration. The advances in nanomedicine in the controlled delivery of active pharmacological agents are remarkable and may provide substantial contribution to the treatment of heart diseases. This review aims to summarize the main mechanisms involved in cardiac remodeling and regeneration and how they have been applied in nanomedicine.

MicroRNA Roles in Cell Reprogramming Mechanisms

Cell reprogramming is a groundbreaking technology that, in few decades, generated a new paradigm in biomedical science. To date we can use cell reprogramming to potentially generate every cell type by converting somatic cells and suitably modulating the expression of key transcription factors. This approach can be used to convert skin fibroblasts into pluripotent stem cells as well as into a variety of differentiated and medically relevant cell types, including cardiomyocytes and neural cells. The molecular mechanisms underlying such striking cell phenotypes are still largely unknown, but in the last decade it has been proven that cell reprogramming approaches are significantly influenced by non-coding RNAs. Specifically, this review will focus on the role of microRNAs in the reprogramming processes that lead to the generation of pluripotent stem cells, neurons, and cardiomyocytes. As highlighted here, non-coding RNA-forced expression can be sufficient to support some cell reprogramming processes, and, therefore, we will also discuss how these molecular determinants could be used in the future for biomedical purposes.

Lyotropic Liquid Crystals: A Biocompatible and Safe Material for Local Cardiac Application

The regeneration of cardiac tissue is a multidisciplinary research field aiming to improve the health condition of the post-heart attack patient. Indeed, myocardial tissue has a poor ability to self-regenerate after severe damage. The scientific efforts focused on the research of a biomaterial able to adapt to heart tissue, thus guaranteeing the in situ release of active substances or growth promoters. Many types of hydrogels were proposed for this purpose, showing several limitations. The aim of this study was to suggest a new usage for glyceryl monooleate-based lyotropic liquid crystals (LLCs) as a biocompatible and inert material for a myocardial application. The main advantages of LLCs are mainly related to their easy in situ injection as lamellar phase and their instant in situ transition in the cubic phase. In vivo studies proved the biocompatibility and the inertia of LLCs after their application on the myocardial tissue of mice. In detail, the cardiac activity was monitored through 28 days, and no significant alterations were recorded in the heart anatomy and functionality. Moreover, gross anatomy showed the ability of LLCs to be bio-degraded in a suitable time frame. Overall, these results permitted us to suppose a potential use of LLCs as materials for cardiac drug delivery.

Reprogramming cellular identity in vivo

Cellular identity is established through complex layers of genetic regulation, forged over a developmental lifetime. An expanding molecular toolbox is allowing us to manipulate these gene regulatory networks in specific cell types in vivo. In principle, if we found the right molecular tricks, we could rewrite cell identity and harness the rich repertoire of possible cellular functions and attributes. Recent work suggests that this rewriting of cell identity is not only possible, but that newly induced cells can mitigate disease phenotypes in animal models of major human diseases. So, is the sky the limit, or do we need to keep our feet on the ground? This Spotlight synthesises key concepts emerging from recent efforts to reprogramme cellular identity in vivo. We provide our perspectives on recent controversies in the field of glia-to-neuron reprogramming and identify important gaps in our understanding that present barriers to progress.

The Role of Matrix Proteins in Cardiac Pathology

The extracellular matrix (ECM) and ECM-regulatory proteins mediate structural and cell-cell interactions that are crucial for embryonic cardiac development and postnatal homeostasis, as well as organ remodeling and repair in response to injury. These proteins possess a broad functionality that is regulated by multiple structural domains and dependent on their ability to interact with extracellular substrates and/or cell surface receptors. Several different cell types (cardiomyocytes, fibroblasts, endothelial and inflammatory cells) within the myocardium elaborate ECM proteins, and their role in cardiovascular (patho)physiology has been increasingly recognized. This has stimulated robust research dissecting the ECM protein function in human health and disease and replicating the genetic proof-of-principle. This review summarizes recent developments regarding the contribution of ECM to cardiovascular disease. The clear importance of this heterogeneous group of proteins in attenuating maladaptive repair responses provides an impetus for further investigation into these proteins as potential pharmacological targets in cardiac diseases and beyond.

Membrane-fusogenic biomimetic particles: a new bioengineering tool learned from nature

Membrane fusion, a fundamental biological process of the fusion of the membrane composition between cells within natural organisms, is vital for cell-cell communication and cargo transport between the living cells....

Improving Cardiac Reprogramming for Heart Regeneration in Translational Medicine

Direct reprogramming of fibroblasts into CM-like cells has emerged as an attractive strategy to generate induced CMs (iCMs) in heart regeneration. However, low conversion rate, poor purity, and the lack of precise conversion of iCMs are still present as significant challenges. In this review, we summarize the recent development in understanding the molecular mechanisms of cardiac reprogramming with various strategies to achieve more efficient iCMs. reprogramming. Specifically, we focus on the identified critical roles of transcriptional regulation, epigenetic modification, signaling pathways from the cellular microenvironment, and cell cycling regulation in cardiac reprogramming. We also discuss the progress in delivery system optimization and cardiac reprogramming in human cells related to preclinical applications. We anticipate that this will translate cardiac reprogramming-based heart therapy into clinical applications. In addition to optimizing the cardiogenesis related transcriptional regulation and signaling pathways, an important strategy is to modulate the pathological microenvironment associated with heart injury, including inflammation, pro-fibrotic signaling pathways, and the mechanical properties of the damaged myocardium. We are optimistic that cardiac reprogramming will provide a powerful therapy in heart regenerative medicine.

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.