Stem cells derived exosomes and biomaterials to modulate autophagy and mend broken hearts.

Autophagy maintains cellular homeostasis and plays a crucial role in managing pathological conditions including ischemic myocardial injury leading to heart failure (HF). Despite treatments, no intervention can replace lost cardiomyocytes. Stem cell therapy offers potential for post-myocardial infarction repair but struggles with poor cell retention due to immune rejection. In the search for effective therapies, stem cell-derived extracellular vesicles (EVs), especially exosomes, have emerged as promising tools. These tiny bioactive molecule carriers play vital roles in intercellular communication and tissue engineering. They offer numerous therapeutic benefits including modulating immune responses, promoting tissue repair, and boosting angiogenesis. Additionally, biomaterials provide a conducive 3D microenvironment for cell, exosome, and biomolecule delivery, and enhance heart muscle strength, making it a comprehensive cardiac repair strategy. In this regard, the current review delves into the intricate application of extracellular vesicles (EVs) and biomaterials for managing autophagy in the heart muscle during cardiac injury. Central to our investigation is the exploration of how these elements interact within the context of cardiac repair and regeneration. Additionally, this review also casts light on the formidable challenges that plague this field, such as the issues of safety, efficacy, controlled delivery, and acceptance of these therapeutic strategies for effective clinical translation. Addressing these challenges is crucial for unlocking the full therapeutic potential of EV and biomaterial-based therapies and ensuring their successful translation from bench to bedside.

Immunoengineered MXene nanosystem for mitigation of alloantigen presentation and prevention of transplant vasculopathy.

MXenes are an emerging class of nanomaterials with significant potential for applications in nanomedicine. Amongst MXene technologies, titanium carbide (Ti3C2Tx) nanomaterials are the most mature and have received significant attention to tackle longstanding clinical challenges due to its tailored physical and material properties. Cardiac allograft vasculopathy is an aggressive form of atherosclerosis and a major cause of mortality among patients with heart transplants. Blood vessel endothelial cells (ECs) stimulate alloreactive T-lymphocytes to result in sustained inflammation. Herein, we report the first application of Ti3C2Tx MXene nanosheets for prevention of allograft vasculopathy. MXene nanosheets interacted with human ECs and downregulated the expression of genes involved in alloantigen presentation, and consequently reduced the activation of allogeneic lymphocytes. RNA-Seq analysis of lymphocytes showed that treatment with MXene downregulated genes responsible for transplant-induced T-cell activation, cell-mediated rejection, and development of allograft vasculopathy. In an in vivo rat model of allograft vasculopathy, treatment with MXene reduced lymphocyte infiltration and preserved medial smooth muscle cell integrity within transplanted aortic allografts. These findings highlight the potential of Ti3C2Tx MXene in treatment of allograft vasculopathy and inflammatory diseases.

Low Dose of Ti3 C2 MXene Quantum Dots Mitigate SARS-CoV-2 Infection.

MXene QDs (MQDs) have been effectively used in several fields of biomedical research. Considering the role of hyperactivation of immune system in infectious diseases, especially in COVID-19, MQDs stand as a potential candidate as a nanotherapeutic against viral infections. However, the efficacy of MQDs against SARS-CoV-2 infection has not been tested yet. In this study, Ti3 C2 MQDs are synthesized and their potential in mitigating SARS-CoV-2 infection is investigated.  Physicochemical characterization suggests that MQDs are enriched with abundance of bioactive functional groups such as oxygen, hydrogen, fluorine, and chlorine groups as well as surface titanium oxides. The efficacy of MQDs is tested in VeroE6 cells infected with SARS-CoV-2. These data demonstrate that the treatment with MQDs is able to mitigate multiplication of virus particles, only at very low doses such as 0,15 µg mL-1 . Furthermore, to understand the mechanisms of MQD-mediated anti-COVID properties, global proteomics analysis are performed and determined differentially expressed proteins between MQD-treated and untreated cells. Data reveal that MQDs interfere with the viral life cycle through different mechanisms including the Ca2 + signaling pathway, IFN-α response, virus internalization, replication, and translation. These findings suggest that MQDs can be employed to develop future immunoengineering-based nanotherapeutics strategies against SARS-CoV-2 and other viral infections.

Proteasomal Degradation of TRAF2 Mediates Mitochondrial Dysfunction in Doxorubicin-Cardiomyopathy.

BACKGROUND: Cytokines such as tumor necrosis factor-α (TNFα) have been implicated in cardiac dysfunction and toxicity associated with doxorubicin (DOX). Although TNFα can elicit different cellular responses, including survival or death, the mechanisms underlying these divergent outcomes in the heart remain cryptic. The E3 ubiquitin ligase TRAF2 (TNF receptor associated factor 2) provides a critical signaling platform for K63-linked polyubiquitination of RIPK1 (receptor interacting protein 1), crucial for nuclear factor-κB (NF-κB) activation by TNFα and survival. Here, we investigate alterations in TNFα-TRAF2-NF-κB signaling in the pathogenesis of DOX cardiotoxicity. METHODS: Using a combination of in vivo (4 weekly injections of DOX 5 mg·kg-1·wk-1) in C57/BL6J mice and in vitro approaches (rat, mouse, and human inducible pluripotent stem cell-derived cardiac myocytes), we monitored TNFα levels, lactate dehydrogenase, cardiac ultrastructure and function, mitochondrial bioenergetics, and cardiac cell viability. RESULTS: In contrast to vehicle-treated mice, ultrastructural defects, including cytoplasmic swelling, mitochondrial perturbations, and elevated TNFα levels, were observed in the hearts of mice treated with DOX. While investigating the involvement of TNFα in DOX cardiotoxicity, we discovered that NF-κB was readily activated by TNFα. However, TNFα-mediated NF-κB activation was impaired in cardiac myocytes treated with DOX. This coincided with loss of K63- linked polyubiquitination of RIPK1 from the proteasomal degradation of TRAF2. Furthermore, TRAF2 protein abundance was markedly reduced in hearts of patients with cancer treated with DOX. We further established that the reciprocal actions of the ubiquitinating and deubiquitinating enzymes cellular inhibitors of apoptosis 1 and USP19 (ubiquitin-specific peptidase 19), respectively, regulated the proteasomal degradation of TRAF2 in DOX-treated cardiac myocytes. An E3-ligase mutant of cellular inhibitors of apoptosis 1 (H588A) or gain of function of USP19 prevented proteasomal degradation of TRAF2 and DOX-induced cell death. Furthermore, wild-type TRAF2, but not a RING finger mutant defective for K63-linked polyubiquitination of RIPK1, restored NF-κB signaling and suppressed DOX-induced cardiac cell death. Last, cardiomyocyte-restricted expression of TRAF2 (cardiac troponin T-adeno-associated virus 9-TRAF2) in vivo protected against mitochondrial defects and cardiac dysfunction induced by DOX. CONCLUSIONS: Our findings reveal a novel signaling axis that functionally connects the cardiotoxic effects of DOX to proteasomal degradation of TRAF2. Disruption of the critical TRAF2 survival pathway by DOX sensitizes cardiac myocytes to TNFα-mediated necrotic cell death and DOX cardiotoxicity.

The role of autophagy in the metabolism and differentiation of stem cells.

Autophagy is a very well-coordinated intracellular process that maintains cellular homeostasis under basal conditions by removing unnecessary or dysfunctional components through orderly degradation and recycling. Under pathological conditions, defects in autophagy have been linked to various human disorders, including neurodegenerative disorders and cancer. The role of autophagy in stem cell proliferation, differentiation, self-renewal, and senescence is well documented. Additionally, cancer stem cells (CSCs) play an important role in tumorigenesis, metastasis and tumor relapse and several studies have suggested the involvement of autophagy in the maintenance and invasiveness of CSCs. Hence, considering the modulation of autophagy in normal and cancer stems cells as a therapeutic approach can lead to the development or improvement of regenerative and anti-cancer therapies. Accordingly, modulation of autophagy can be regarded as a target for stem cell-based therapy of diseases with abnormal levels of autophagy. This article is focused on understanding the role of autophagy in stem cell homeostasis with an emphasis on the therapeutic potential of targeting autophagy for future therapies.

Development of iPSC-based clinical trial selection platform for patients with ultrarare diseases.

A "Leap-of-Faith" approach is used to treat patients with previously unknown ultrarare pathogenic mutations, often based on evidence from patients having dissimilar but more prevalent mutations. This uncertainty reflects the need to develop personalized prescreening platforms for these patients to assess drug efficacy before considering clinical trial enrollment. In this study, we report an 18-year-old patient with ultrarare Leigh-like syndrome. This patient had previously participated in two clinical trials with unfavorable responses. We established an induced pluripotent stem cell (iPSC)-based platform for this patient, and assessed the efficacy of a panel of drugs. The iPSC platform validated the safety and efficacy of the screened drugs. The efficacy of three of the screened drugs was also investigated in the patient. After 3 years of treatment, the drugs were effective in shifting the metabolic profile of this patient toward healthy control. Therefore, this personalized iPSC-based platform can act as a prescreening tool to help in decision-making with respect to patient's participation in future clinical trials.

Generation and Evaluation of Isogenic iPSC as a Source of Cell Replacement Therapies in Patients with Kearns Sayre Syndrome.

Kearns Sayre syndrome (KSS) is mitochondrial multisystem disorder with no proven effective treatment. The underlying cause for multisystem involvement is the energy deficit resulting from the load of mutant mitochondrial DNA (mtDNA), which manifests as loss of cells and tissue dysfunction. Therefore, functional organ or cellular replacement provides a promising avenue as a therapeutic option. Patient-specific induced pluripotent stem cells (iPSC) have become a handy tool to create personalized cell -based therapies. iPSC are capable of self-renewal, differentiation into all types of body cells including cardiomyocytes (CM) and neural progenitor cells (NPC). In KSS patients, mutations in mtDNA are largely found in the muscle tissue and are predominantly absent in the blood cells. Therefore, we conceptualized that peripheral blood mononuclear cells (PBMNC) from KSS patients can be reprogrammed to generate mutation free, patient specific iPSC lines that can be used as isogenic source of cell replacement therapies to treat affected organs. In the current study we generated iPSC lines from two female patients with clinical diagnosis of classic KSS. Our data demonstrate that iPSC from these KSS patients showed normal differentiation potential toward CM, NPC and fibroblasts without any mtDNA deletions over passages. Next, we also found that functional studies including ATP production, reactive oxygen species generation, lactate accumulation and mitochondrial membrane potential in iPSC, CM, NPC and fibroblasts of these KSS patients were not different from respective cells from healthy controls. PBMNCs from these KSS patients in the current study did not reproduce mtDNA mutations which were present in muscle biopsies. Furthermore, we demonstrate for the first time that this phenomenon provides opportunities to create isogenic mutation free iPSC with absent or very low level of expression of mtDNA deletion which can be banked for future cell replacement therapies in these patients as the disease progresses.

Human induced pluripotent stem cell (hiPSC) line UOMi006-A derived from PBMCs of a patient with Kearns-Sayre syndrome.

Induced pluripotent stem cell (iPSC) line was derived from peripheral blood mononuclear cells (PBMCs) of a Kearns-Sayre syndrome (KSS) patient with mtDNA deletion of 4.8 kilobase fragment. KSS is an ultrarare multi-organ disorder and is characterized with (1.1 to 10 kilobase) deletion of mitochondrial DNA (mtDNA) with a frequency of ~1 in 100,000 individuals. Heteroplasmy in PBMCs allowed us to generate an iPSC line with normal mitochondrial DNA that can be used to study therapeutic prospective of iPSC and their derivatives and design future cell replacement therapies.

Carbon nanomaterials for cardiovascular theranostics: Promises and challenges.

Cardiovascular diseases (CVDs) are the leading cause of death worldwide. Heart attack and stroke cause irreversible tissue damage. The currently available treatment options are limited to "damage-control" rather than tissue repair. The recent advances in nanomaterials have offered novel approaches to restore tissue function after injury. In particular, carbon nanomaterials (CNMs) have shown significant promise to bridge the gap in clinical translation of biomaterial based therapies. This family of carbon allotropes (including graphenes, carbon nanotubes and fullerenes) have unique physiochemical properties, including exceptional mechanical strength, electrical conductivity, chemical behaviour, thermal stability and optical properties. These intrinsic properties make CNMs ideal materials for use in cardiovascular theranostics. This review is focused on recent efforts in the diagnosis and treatment of heart diseases using graphenes and carbon nanotubes. The first section introduces currently available derivatives of graphenes and carbon nanotubes and discusses some of the key characteristics of these materials. The second section covers their application in drug delivery, biosensors, tissue engineering and immunomodulation with a focus on cardiovascular applications. The final section discusses current shortcomings and limitations of CNMs in cardiovascular applications and reviews ongoing efforts to address these concerns and to bring CNMs from bench to bedside.

Fabrication of Smart Tantalum Carbide MXene Quantum Dots with Intrinsic Immunomodulatory Properties for Treatment of Allograft Vasculopathy.

MXene nanomaterials have sparked significant interest among interdisciplinary researchers to tackle today's medical challenges. In particular, colloidal MXene quantum dots (MQDs) offer the high specific surface area and compositional flexibility of MXene while providing improvements to aqueous stability and material-cell interactions. The current study for the first time reports the development and application of immunoengineered tantalum-carbide (Ta4C3T x ) MQDs for in vivo treatment of transplant vasculopathy. This report comes at a critical juncture in the field as poor long-term safety of other MXene compositions challenge the eventual clinical translatability of these materials. Using rational design and synthesis strategies, the Ta4C3T x MQDs leverage the intrinsic anti-inflammatory and antiapoptotic properties of tantalum to provide a novel nanoplatform for biomedical engineering. In particular, these MQDs are synthesized with high efficiency and purity using a facile hydrofluoric acid-free protocol and are enriched with different bioactive functional groups and stable surface TaO2 and Ta2O5. Furthermore, MQDs are spontaneously uptaken into antigen-presenting endothelial cells and alter surface receptor expression to reduce their activation of allogeneic T-lymphocytes. Finally, when applied in vivo, Ta4C3T x MQDs ameliorate the cellular and structural changes of early allograft vasculopathy. These findings highlight the robust potential of tailored Ta4C3T x MQDs for future applications in medicine.

Hypoxia-induced shift in the phenotype of proteasome from 26S toward immunoproteasome triggers loss of immunoprivilege of mesenchymal stem cells.

Allogeneic mesenchymal stem cells (MSCs) are immunoprivileged and are being investigated in phase I and phase II clinical trials to treat different degenerative and autoimmune diseases. In spite of encouraging outcome of initial trials, the long-term poor survival of transplanted cells in the host tissue has declined the overall enthusiasm. Recent analyses of allogeneic MSCs based studies confirm that after transplantation in the hypoxic or ischemic microenvironment of diseased tissues, MSCs become immunogenic and are rejected by recipient immune system. The immunoprivilege of MSCs is preserved by absence or negligible expression of cell surface antigen, human leukocyte antigen (HLA)-DRα. We found that in normoxic MSCs, 26S proteasome degrades HLA-DRα and maintains immunoprivilege of MSCs. The exposure to hypoxia leads to inactivation of 26S proteasome and formation of immunoproteasome in MSCs, which is associated with upregulation and activation of HLA-DRα, and as a result, MSCs become immunogenic. Furthermore, inhibition of immunoproteasome formation in hypoxic MSCs preserves the immunoprivilege. Therefore, hypoxia-induced shift in the phenotype of proteasome from 26S toward immunoproteasome triggers loss of immunoprivilege of allogeneic MSCs. The outcome of the current study may provide molecular targets to plan interventions to preserve immunoprivilege of allogeneic MSCs in the hypoxic or ischemic environment.

Application of injectable hydrogels for cardiac stem cell therapy and tissue engineering.

Cardiovascular diseases are responsible for approximately one-third of deaths around the world. Among cardiovascular diseases, the largest single cause of death is ischemic heart disease. Ischemic heart disease typically manifests as progressive constriction of the coronary arteries, which obstructs blood flow to the heart and can ultimately lead to myocardial infarction. This adversely affects the structure and function of the heart. Conventional treatments lack the ability to treat the myocardium lost during an acute myocardial infarction. Stem cell therapy offers an excellent solution for myocardial regeneration. Stem cell sources such as adult stem cells, embryonic and induced pluripotent stem cells have been the focal point of research in cardiac tissue engineering. However, cell survival and engraftment post-transplantation are major limitations that must be addressed prior to widespread use of this technology. Recently, biomaterials have been introduced as 3D vehicles to facilitate stem cell transplantation into infarct sites. This has shown significant promise with improved cell survival after transplantation. In this review, we discuss the various injectable hydrogels that have been tried in cardiac tissue engineering. Exploring and optimizing these cell-material interactions will guide cardiac tissue engineering towards developing stem cell based functional 3D constructs for cardiac regeneration.