Synthetic sulfonyl-hydrazone-1 positively regulates cardiomyogenic microRNA expression and cardiomyocyte differentiation of induced pluripotent stem cells

Medicinal applications of vanadium complexes with Schiff bases

Many transition metal complexes have been explored for their therapeutic properties after the discovery of cisplatin. Schiff bases have an efficient complexation tendency with the transition metals and several medicinal properties have been reported. However, fewer studies have reported the medicinal utility of vanadium and its Schiff base complexes. This paper provides a comprehensive overview of vanadium complexes with Schiff bases along with their mechanistic insight. Vanadium complexes in + 4 and + 5 oxidation states have exhibited well-defined geometry and found to be thermodynamically stable. The studies have reported the G0/G1 phase cell cycle arrest and decreased delta psi m, inducing mitochondrial membrane depolarization in cancer cell lines along with the alterations in the metabolism of the cancer cells upon dosing with the vanadium complexes. Cancer cell invasion and growth are also found to be markedly reduced by peroxo complexes of vanadium. The studies included in the review paper have been taken from leading indexing databases and focus was laid on recent reports in literature. The biological potential of vanadium complexes of Schiff bases opens new horizons for future interdisciplinary studies and investigation focussed on understanding the biochemistry of these complexes, along with designing new complexes which have better bioavailability, solubility and low or non-toxicity.

Recent Advances in Apoptosis: THE Role of Hydrazones

The process of programmed cell death in higher eukaryotes (apoptosis), is generally characterized by distinct morphological characteristics and energy-dependent biochemical mechanisms. Apoptosis is considered as a vital component of various processes including normal cell turnover, proper development and functioning of the immune system, hormone-dependent atrophy, embryonic development and chemical-induced cell death. Apoptosis seems to play an important key role in the progression of several human diseases like Alzheimer's disease, Parkinson's disease and many types of cancer. Promotion of apoptosis may be a good approach for the prevention of cancer cell proliferation. In early studies, antitumor compounds have been found to induce the apoptotic process in tumor cells. On the other hand, several hydrazones were reported to have lower toxicity than hydrazides due to the blockage of -NH2 group. Therefore, the design of hydrazones that activate and promote apoptosis is an attractive strategy for the discovery and development of potential anticancer agents. The aim of this review is to provide a general overview of current knowledge and the connection between apoptosis and hydrazone. It is also the guide for the apoptotic activities of new hydrazone derivatives.

Cell-Based Therapies for Cardiac Regeneration: A Comprehensive Review of Past and Ongoing Strategies

Despite considerable improvements in the treatment of cardiovascular diseases, heart failure (HF) still represents one of the leading causes of death worldwide. Poor prognosis is mostly due to the limited regenerative capacity of the adult human heart, which ultimately leads to left ventricular dysfunction. As a consequence, heart transplantation is virtually the only alternative for many patients. Therefore, novel regenerative approaches are extremely needed, and several attempts have been performed to improve HF patients’ clinical conditions by promoting the replacement of the lost cardiomyocytes and by activating cardiac repair. In particular, cell-based therapies have been shown to possess a great potential for cardiac regeneration. Different cell types have been extensively tested in clinical trials, demonstrating consistent safety results. However, heterogeneous efficacy data have been reported, probably because precise end-points still need to be clearly defined. Moreover, the principal mechanism responsible for these beneficial effects seems to be the paracrine release of antiapoptotic and immunomodulatory molecules from the injected cells. This review covers past and state-of-the-art strategies in cell-based heart regeneration, highlighting the advantages, challenges, and limitations of each approach.

Vanadyl complexes discriminate between neuroblastoma cells and primary neurons by inducing cell-specific apoptotic pathways

Vanadium compounds have arisen as potential therapeutic agent for the treatment of cancers over the past decades. A few studies suggested that vanadyl complexes may discriminate between the cancerous and the normal cells. Here, we reported the investigation on the pro-apoptotic effect and the underlying mechanism of bis(acetylacetonato) oxovanadium(IV) ([VO(acac)₂]) on SH-SY5Y neuroblastoma cells in comparison with that of mouse primary cortex neurons. The experimental results revealed that [VO(acac)₂] showed about 10-fold higher cytotoxicity (IC50 ~16 μM) on the neuroblastoma cells than on normal neurons (IC50 ~250 μM). Further analysis indicated that the vanadyl complex suppressed the growth of neuroblastoma cells via different pathways depending on its concentration. It induced a special cyclin D-mediated and p53-independent cell apoptosis at <50 μM but cell cycle arrests at >50 μM. In contrast, [VO(acac)₂] promoted cell viability of primary neurons in the concentration range of 0-150 μM; while [VO(acac)₂] at hundreds of μM would cause neuronal death possibly via the reactive oxygen species (ROS)-mediated signal pathways. The extraordinary discrimination between neuroblastoma cells and primary neurons suggests potential application of vanadyl complexes for therapeutic treatment of neuroblastoma. In addition, the p53-independent apoptotic pathways induced by vanadyl complexes may provide new insights for future discovery of new anticancer drugs overcoming the chemo-resistance due to p53 mutation.

A chemical approach to myocardial protection and regeneration

The possibility of generating induced pluripotent stem cells from mouse embryonic fibroblasts and human adult fibroblasts has introduced new perspectives for possible therapeutic strategies to repair damaged hearts. However, obtaining large numbers of adult stem cells is still an ongoing challenge, and the safety of genetic reprogramming with lenti- or retro-viruses has several drawbacks not easy to be addressed. Furthermore, the majority of adult stem cell-based clinical trials for heart regeneration have had generally poor and controversial results. Nonetheless, it is now clear that the injected cells activate the growth and differentiation of progenitor cells that are already present in the heart. This is achieved by the release of signalling factors and/or exosomes carrying them. Along this line, chemistry may play a major role in developing new strategies for activating resident stem cells to regenerate the heart. In particular, this review focuses on small molecule approaches for cell reprogramming, cell differentiation, and activation of cell protection.

Pluripotent reprogramming and lineage reprogramming: promises and challenges in cardiovascular regeneration

Cardiovascular disease is a leading cause of death in industrialized countries. Scientists are trying to generate cardiomyocytes in vitro and in vivo to repair damaged heart tissue. Pluripotent reprogramming brings an alternative source of embryonic-like stem cells, and the possibility of regenerating mammalian tissues by first reverting somatic cells to induced pluripotent stem cells, followed by redifferentiating these cells into cardiomyocytes. More recently, lineage reprogramming of fibroblasts directly into functional cardiomyocytes has been reported. The procedure does not involve reverting cells back to a pluripotent stage, and, thus, would presumably reduce tumorigenic potential. Interestingly, lineage reprogramming could be used for in situ conversion of cell fate. Moreover, zebrafish-like regenerative mechanism in mammalian heart tissue, which was observed in mice within the first week of postpartum, should be further addressed. Here, we review the landmark progresses of the two major reprogramming strategies, compare their pros and cons in cardiovascular regeneration, and forecast the future directions of cardiac repair.

Current status of induced pluripotent stem cells in cardiac tissue regeneration and engineering

Myocardial infarction (MI) is associated with damage to the myocardium which results in a great loss of functional cardiomyocytes. As one of the most terminally differentiated organs, the endogenous regenerative potentials of adult hearts are extremely limited and insufficient to compensate for the myocardial loss occurring after MI. Consequentially, exogenous regenerative strategies, especially cell replacement therapy, have emerged and attracted increasing more attention in the field of cardiac tissue regeneration. A renewable source of seeding cells is therefore one of the most important subject in the field. Induced pluripotent stem cells (iPSCs), embryonic stem cell (ESC)-like cells that are derived from somatic cells by reprogramming, represent a promising candidate due to their high potentials for self-renewal, proliferation, differentiation and more importantly, they provide an invaluable method of deriving patient-specific pluripotent stem cells. Therefore, iPSC-based cardiac tissue regeneration and engineering has been extensively investigated in recent years. This review will discuss the achievements and current status in this field, including development of iPSC derivation, in vitro strategies for cardiac generation from iPSCs, cardiac application of iPSCs, challenges confronted at present as well as perspective in the future.

Cardiomyocyte culture - an update on the in vitro cardiovascular model and future challenges

The success of any work with isolated cardiomyocytes depends on the reproducibility of cell isolation, because the cells do not divide. To date, there is no suitable in vitro model to study human adult cardiac cell biology. Although embryonic stem cells and induced pluripotent stem cells are able to differentiate into cardiomyocytes in vitro, the efficiency of this process is low. Isolation and expansion of human cardiomyocyte progenitor cells from cardiac surgical waste or, alternatively, from fetal heart tissue is another option. However, to overcome various issues related to human tissue usage, especially ethical concerns, researchers use large- and small-animal models to study cardiac pathophysiology. A simple model to study the changes at the cellular level is cultures of cardiomyocytes. Although primary murine cardiomyocyte cultures have their own advantages and drawbacks, alternative strategies have been developed in the last two decades to minimise animal usage and interspecies differences. This review discusses the use of freshly isolated murine cardiomyocytes and cardiomyocyte alternatives for use in cardiac disease models and other related studies.

Inhibition of cardiomyocytes differentiation of mouse embryonic stem cells by CD38/cADPR/Ca2+ signaling pathway

Cyclic adenosine diphosphoribose (cADPR) is an endogenous Ca²⁺ mobilizing messenger that is formed by ADP-ribosyl cyclases from nicotinamide adenine dinucleotide (NAD). The main ADP-ribosyl cyclase in mammals is CD38, a multi-functional enzyme and a type II membrane protein. Here we explored the role of CD38-cADPR-Ca²⁺ in the cardiomyogenesis of mouse embryonic stem (ES) cells. We found that the mouse ES cells are responsive to cADPR and possess the key components of the cADPR signaling pathway. In vitro cardiomyocyte (CM) differentiation of mouse ES cells was initiated by embryoid body (EB) formation. Interestingly, beating cells appeared earlier and were more abundant in CD38 knockdown EBs than in control EBs. Real-time RT-PCR and Western blot analyses further showed that the expression of several cardiac markers, including GATA4, MEF2C, NKX2.5, and α-MLC, were increased markedly in CD38 knockdown EBs than those in control EBs. Similarly, FACS analysis showed that more cardiac Troponin T-positive CMs existed in CD38 knockdown or 8-Br-cADPR, a cADPR antagonist, treated EBs compared with that in control EBs. On the other hand, overexpression of CD38 in mouse ES cells significantly inhibited CM differentiation. Moreover, CD38 knockdown ES cell-derived CMs possess the functional properties characteristic of normal ES cell-derived CMs. Last, we showed that the CD38-cADPR pathway negatively modulated the FGF4-Erks1/2 cascade during CM differentiation of ES cells, and transiently inhibition of Erk1/2 blocked the enhanced effects of CD38 knockdown on the differentiation of CM from ES cells. Taken together, our data indicate that the CD38-cADPR-Ca²⁺ signaling pathway antagonizes the CM differentiation of mouse ES cells.

Generation, characterization, and potential therapeutic applications of cardiomyocytes from various stem cells

Heart failure is one of the leading causes of death worldwide. Myocardial cell transplantation emerges as a novel therapeutic strategy for heart failure, but this approach has been hampered by severe shortage of human cardiomyocytes. We have recently induced mouse embryonic stem cells to differentiate into embryoid bodies and eventually, cardiomyocytes. Here, we address recent advancements in cardiomyocyte differentiation from cardiac stem cells and pluripotent stem cells. We highlight the methodologies, using growth factors, endoderm-like cell cocultures, small molecules, and biomaterials, in directing the differentiation of pluripotent stem cells into cardiomyocytes. The characterization and identification of pluripotent stem cell-derived cardiomyocytes by morphological, phenotypic, and functional features are also discussed. Notably, increasing evidence demonstrates that cardiomyocytes may be generated from the stem cells of several tissues outside the cardiovascular system, including skeletal muscles, bone marrow, testes, placenta, amniotic fluid, and adipose tissues. We further address the potential applications of cardiomyocytes derived from various kinds of stem cells. The differentiation of stem cells into functional cardiomyocytes, especially from an extra-cardiac stem cell source, would circumvent the scarcity of heart donors and human cardiomyocytes, and, most importantly, it would offer an ideal and promising cardiomyocyte source for cell therapy and tissue engineering in treating heart failure.

Prospective in vitro models of channelopathies and cardiomyopathies

An in vitro heart disease model is a promising model used for identifying the genes responsible for the disease, evaluating the effects of drugs, and regenerative medicine. We were interested in disease models using a patient-induced pluripotent stem (iPS) cell-derived cardiomyocytes because of their similarity to a patient's tissues. However, as these studies have just begun, we would like to review the literature in this and other related fields and discuss the path for future models of molecular biology that can help to diagnose and cure diseases, and its involvement in regenerative medicine. The heterogeneity of iPS cells and/or differentiated cardiomyocytes has been recognized as a problem. An in vitro heart disease model should be evaluated using molecular biological analyses, such as mRNA and micro-RNA expression profiles and proteomic analysis.

Pharmacologic and genetic strategies to enhance cell therapy for cardiac regeneration

Cell-based therapy is emerging as an exciting potential therapeutic approach for cardiac regeneration following myocardial infarction (MI). As heart failure (HF) prevalence increases over time, development of new interventions designed to aid cardiac recovery from injury are crucial and should be considered more broadly. In this regard, substantial efforts to enhance the efficacy and safety of cell therapy are continuously growing along several fronts, including modifications to improve the reprogramming efficiency of inducible pluripotent stem cells (iPS), genetic engineering of adult stem cells, and administration of growth factors or small molecules to activate regenerative pathways in the injured heart. These interventions are emerging as potential therapeutic alternatives and/or adjuncts based on their potential to promote stem cell homing, proliferation, differentiation, and/or survival. Given the promise of therapeutic interventions to enhance the regenerative capacity of multipotent stem cells as well as specifically guide endogenous or exogenous stem cells into a cardiac lineage, their application in cardiac regenerative medicine should be the focus of future clinical research. This article is part of a special issue entitled "Key Signaling Molecules in Hypertrophy and Heart Failure."

Development of a New Tool for 3D Modeling for Regenerative Medicine

The effectiveness of therapeutic treatment based on regenerative medicine for degenerative diseases (i.e., neurodegenerative or cardiac diseases) requires tools allowing the visualization and analysis of the three-dimensional (3D) distribution of target drugs within the tissue. Here, we present a new computational procedure able to overcome the limitations of visual analysis emerging by the examination of a molecular signal within images of serial tissue/organ sections by using the conventional techniques. Together with the 3D anatomical reconstitution of the tissue/organ, our framework allows the detection of signals of different origins (e.g., marked generic molecules, colorimetric, or fluorimetric substrates for enzymes; microRNA; recombinant protein). Remarkably, the application does not require the employment of specific tracking reagents for the imaging analysis. We report two different representative applications: the first shows the reconstruction of a 3D model of mouse brain with the analysis of the distribution of theβ-Galactosidase, the second shows the reconstruction of a 3D mouse heart with the measurement of the cardiac volume.