miRNA-Guided Regulation of Mesenchymal Stem Cells Derived from the Umbilical Cord: Paving the Way for Stem-Cell Based Regeneration and Therapy.

The human body is an abundant source of multipotent cells primed with unique properties that can be exploited in a multitude of applications and interventions. Mesenchymal stem cells (MSCs) represent a heterogenous population of undifferentiated cells programmed to self-renew and, depending on their origin, differentiate into distinct lineages. Alongside their proven ability to transmigrate toward inflammation sites, the secretion of various factors that participate in tissue regeneration and their immunoregulatory function render MSCs attractive candidates for use in the cytotherapy of a wide spectrum of diseases and conditions, as well as in different aspects of regenerative medicine. In particular, MSCs that can be found in fetal, perinatal, or neonatal tissues possess additional capabilities, including predominant proliferation potential, increased responsiveness to environmental stimuli, and hypoimmunogenicity. Since microRNA (miRNA)-guided gene regulation governs multiple cellular functions, miRNAs are increasingly being studied in the context of driving the differentiation process of MSCs. In the present review, we explore the mechanisms of miRNA-directed differentiation of MSCs, with a special focus on umbilical cord-derived mesenchymal stem cells (UCMSCs), and we identify the most relevant miRNAs and miRNA sets and signatures. Overall, we discuss the potent exploitations of miRNA-driven multi-lineage differentiation and regulation of UCMSCs in regenerative and therapeutic protocols against a range of diseases and/or injuries that will achieve a meaningful clinical impact through maximizing treatment success rates, while lacking severe adverse events.

Suitability of Human Mesenchymal Stem Cells Derived from Fetal Umbilical Cord (Wharton's Jelly) as an Alternative In Vitro Model for Acute Drug Toxicity Screening.

Preclinical toxicity screening is the first and most crucial test that assesses the safety of new candidate drugs before their consideration for further evaluation in clinical trials. In vitro drug screening using stem cells has lately arisen as a promising alternative to the "gold standard" of animal testing, but their suitability and performance characteristics in toxicological studies have so far not been comprehensively investigated. In this study, we focused on the evaluation of human mesenchymal stem cells isolated from the matrix (Wharton's jelly) of fetal umbilical cord (WJSCs), which bear enhanced in vitro applicability due to their unique biological characteristics. In order to determine their suitability for drug-related cytotoxicity assessment, we adopted a high-throughput methodology that evaluated their sensitivity to a selected panel of chemicals in different culture environments. Cytotoxicity was measured within 48 h by means of MTS and/or NRU viability assays, and was compared directly (in vitro) or indirectly (in silico) to adult human mesenchymal stem cells and to reference cell lines of human and murine origin. Our data clearly suggest that human WJSCs can serve as a robust in vitro alternative for acute drug toxicity screening by uniquely combining rapid and versatile assay setup with high-throughput analysis, good representation of human toxicology, high reproducibility, and low cost.

Protective role of taurine against oxidative stress (Review).

Taurine is a fundamental mediator of homeostasis that exerts multiple roles to confer protection against oxidant stress. The development of hypertension, muscle/neuro­â€‹associated disorders, hepatic cirrhosis, cardiac dysfunction and ischemia/reperfusion are examples of some injuries that are linked with oxidative stress. The present review gives a comprehensive description of all the underlying mechanisms of taurine, with the aim to explain its anti­oxidant actions. Taurine is regarded as a cytoprotective molecule due to its ability to sustain normal electron transport chain, maintain glutathione stores, upregulate anti­oxidant responses, increase membrane stability, eliminate inflammation and prevent calcium accumulation. In parallel, the synergistic effect of taurine with other potential therapeutic modalities in multiple disorders are highlighted. Apart from the results derived from research findings, the current review bridges the gap between bench and bedside, providing mechanistic insights into the biological activity of taurine that supports its potential therapeutic efficacy in clinic. In the future, further clinical studies are required to support the ameliorative effect of taurine against oxidative stress.

Potential Relationship Between Lifestyle Changes and Incidence of Hospital Admissions for Acute Coronary Syndrome During the COVID-19 Lockdown.

Aims: To evaluate the impact of lockdown during the COVID-19 pandemic on lifestyle changes of the general population, and on admissions for acute coronary syndrome (ACS). Methods and Results: All ACS admissions during the COVID-19 lockdown (10 March to 4 May, 2020), in 3 municipalities (3 spoke, and 1 hub hospital), in Southwestern Greece (411,576 inhabitants), were prospectively recorded and compared to the equivalent periods during 2018, and 2019. A telephone survey of 1014 participants was conducted to explore the lifestyle habits of citizens aged ≥35-years-old before and during lockdown. The median ACS incidence rate decreased from 19.0 cases per week in 2018 and 21.5 in 2019 down to 13.0 in 2020 (RR: 0.66 during the Covid-19 lockdown; 95%CI: 0.53-0.82; P = 0.0002). This was driven by a significant reduction of admissions for Non-ST elevation myocardial infarction (NSTEMI) (RR: 0.68; 95%CI: 0.52-0.88; P = 0.0037), mainly in patients with a lower burden of cardiovascular risk factors, as we noticed an inverse association between the reduction of the incidence of ACS during the Covid-19 lockdown period and the number of registered patient risk factors. There was no difference in the rates of STEMI and population-based all-cause mortality across the examined time periods. The telephone survey demonstrated reduction of passive smoking, working hours, alcohol, junk food and salt consumption, and an increase in sleeping hours, mainly in participants with a lower burden of cardiovascular risk factors. Conclusions: A significant decline in ACS admissions during the COVID-19 lockdown was noted, affecting mainly NSTEMI patients with a lower burden of cardiovascular risk factors. This was accompanied by significant lifestyle changes. Thus, it is tempting to speculate that to some extend the latter might be associated with the observed decline in ACS admissions.

Ameliorative effect of taurine against diabetes and renal-associated disorders (Review).

To develop novel therapeutic methods for both diabetic and renal disorders, scientists had initially focused on elucidating the molecular mechanisms of taurine in established cell lines and mouse models. Although a large amount of data have been revealed, taurine has been confirmed to be the next step of novel promising therapeutic interventions against diabetic disorders. Taurine appears to ameliorate diabetes 1-related complications in various organs through its antioxidant, anti-inflammatory and anti-hormonal actions. In type 2 diabetes, taurine has been positively implicated in glucose homeostasis, exerting potent hypoglycemic, anti-obesity, hypotensive and hypolipidemic effects. Of particular interest is that taurine provides protection against renal dysfunction, including hypertension and proteinuria, specific glomerular and tubular disorders, acute and chronic renal conditions, and diabetic nephropathy. The ameliorative effects of taurine against renal disorders are based on its osmoregulatory properties, its association with signaling pathways and its association with the renin-angiotensin-aldosterone system (RAAS). Further clinical studies are required to ensure the importance of research findings.

Of numbers and movement - understanding transcription factor pathogenesis by advanced microscopy.

Transcription factors (TFs) are life-sustaining and, therefore, the subject of intensive research. By regulating gene expression, TFs control a plethora of developmental and physiological processes, and their abnormal function commonly leads to various developmental defects and diseases in humans. Normal TF function often depends on gene dosage, which can be altered by copy-number variation or loss-of-function mutations. This explains why TF haploinsufficiency (HI) can lead to disease. Since aberrant TF numbers frequently result in pathogenic abnormalities of gene expression, quantitative analyses of TFs are a priority in the field. In vitro single-molecule methodologies have significantly aided the identification of links between TF gene dosage and transcriptional outcomes. Additionally, advances in quantitative microscopy have contributed mechanistic insights into normal and aberrant TF function. However, to understand TF biology, TF-chromatin interactions must be characterised in vivo, in a tissue-specific manner and in the context of both normal and altered TF numbers. Here, we summarise the advanced microscopy methodologies most frequently used to link TF abundance to function and dissect the molecular mechanisms underlying TF HIs. Increased application of advanced single-molecule and super-resolution microscopy modalities will improve our understanding of how TF HIs drive disease.

Yorkie controls tube length and apical barrier integrity during airway development.

Epithelial organ size and shape depend on cell shape changes, cell-matrix communication, and apical membrane growth. The Drosophila melanogaster embryonic tracheal network is an excellent model to study these processes. Here, we show that the transcriptional coactivator of the Hippo pathway, Yorkie (YAP/TAZ in vertebrates), plays distinct roles in the developing Drosophila airways. Yorkie exerts a cytoplasmic function by binding Drosophila Twinstar, the orthologue of the vertebrate actin-severing protein Cofilin, to regulate F-actin levels and apical cell membrane size, which are required for proper tracheal tube elongation. Second, Yorkie controls water tightness of tracheal tubes by transcriptional regulation of the δ-aminolevulinate synthase gene (Alas). We conclude that Yorkie has a dual role in tracheal development to ensure proper tracheal growth and functionality.

Towards sustainable business models for electric vehicle battery second use: A critical review.

A global mass market adoption of electric vehicles (EVs) is still hindered by the high costs of lithium-ion batteries (LIBs). Repurposing degraded EV batteries in second use applications holds the potential to reduce first-cost impediments of EVs. New business models are emerging rapidly within the EV and battery second use (B2U) industries but they focus on economic aspects without integrating social and environmental dimensions. Simultaneously, the emerging research topic around sustainable business models (SBMs) seem to be able to bridge the environmental management concerns in conjunction with economic and social changes. This paper addresses this paucity in the literature by offering an interdisciplinary approach by drawing upon key perspectives from the emerging sustainable technology of EVs and its underlying B2U market in relation to SBMs. Findings reveal major contributions to theorists and practitioners. B2U holds the potential to facilitate current unsustainable practices in the EV industry. This in turn, will lead towards a faster EV market uptake and improvements of overall sustainability performance through SBM perspectives. Accordingly, a B2U business model framework is conceptualised that embodies the cross-sector multi-stakeholder impact and the shared value creation mechanism for the EV industry and emerging B2U market. We finally conclude that as such B2U holds the potential to prove itself to be a viable and efficient case for sustainability. This can be implemented by taking a multi-stakeholder network centric business model design compared to traditionally firm-centric models, which ultimately refreshes the traditional business models on sustainability.

DPS-2: A Novel Dual MEK/ERK and PI3K/AKT Pathway Inhibitor with Powerful Ex Vivo and In Vivo Anticancer Properties.

Development of novel bioactive compounds against KRAS and/or BRAF mutant colorectal cancer (CRC) is currently an urgent need in oncology. In addition, single or multitarget kinase inhibitors against MEK/ERK and PI3K/AKT pathways are of potential therapeutic advantage. A new compound based on the benzothiophene nucleus was synthesized, based on previous important outcomes on other pharmaceutical preparations, to be tested as potential anticancer agent. Treatments by 2-5 µM DPS-2 of several CRC and melanoma cell lines bearing either BRAF or KRAS mutations have shown a remarkable effect on cell viability in 2D and 3D cultures. More detailed analysis has shown that DPS-2 can kill cancer cells by apoptosis, reducing at the same time their autophagy properties. After testing activities of several signaling pathways, the compound was found to have a dual inhibition of two major proliferative/survival pathways, MEK/ERK and PI3K/AKT, in both CRC and melanoma, thus providing a mechanistic evidence for its potent anticancer activity. Antitumor activity of DPS-2 was further validated in vivo, as DPS-2 treatment of mouse xenografts of Colo-205 colorectal cancer cells remarkably reduced their tumor formation properties. Our findings suggest that DPS-2 has significant anti-KRAS/ anti-BRAF mutant CRC activity in preclinical models, potentially providing a novel treatment strategy for these difficult-to-treat tumors, which needs to be further exploited.

Mesenchymal stem cells in preclinical cancer cytotherapy: a systematic review.

Mesenchymal stem cells (MSC) comprise a heterogeneous population of rapidly proliferating cells that can be isolated from adult (e.g., bone marrow, adipose tissue) as well as fetal (e.g., umbilical cord) tissues (termed bone marrow (BM)-, adipose tissue (AT)-, and umbilical cord (UC)-MSC, respectively) and are capable of differentiation into a wide range of non-hematopoietic cell types. An additional, unique attribute of MSC is their ability to home to tumor sites and to interact with the local supportive microenvironment which rapidly conceptualized into MSC-based experimental cancer cytotherapy at the turn of the century. Towards this purpose, both naïve (unmodified) and genetically modified MSC (GM-MSC; used as delivery vehicles for the controlled expression and release of antitumorigenic molecules) have been employed using well-established in vitro and in vivo cancer models, albeit with variable success. The first approach is hampered by contradictory findings regarding the effects of naïve MSC of different origins on tumor growth and metastasis, largely attributed to inherent biological heterogeneity of MSC as well as experimental discrepancies. In the second case, although the anti-cancer effect of GM-MSC is markedly improved over that of naïve cells, it is yet apparent that some protocols are more efficient against some types of cancer than others. Regardless, in order to maximize therapeutic consistency and efficacy, a deeper understanding of the complex interaction between MSC and the tumor microenvironment is required, as well as examination of the role of key experimental parameters in shaping the final cytotherapy outcome. This systematic review represents, to the best of our knowledge, the first thorough evaluation of the impact of experimental anti-cancer therapies based on MSC of human origin (with special focus on human BM-/AT-/UC-MSC). Importantly, we dissect the commonalities and differences as well as address the shortcomings of work accumulated over the last two decades and discuss how this information can serve as a guide map for optimal experimental design implementation ultimately aiding the effective transition into clinical trials.

CRISPR therapeutic tools for complex genetic disorders and cancer (Review).

One of the fundamental discoveries in the field of biology is the ability to modulate the genome and to monitor the functional outputs derived from genomic alterations. In order to unravel new therapeutic options, scientists had initially focused on inducing genetic alterations in primary cells, in established cancer cell lines and mouse models using either RNA interference or cDNA overexpression or various programmable nucleases [zinc finger nucleases (ZNF), transcription activator-like effector nucleases (TALEN)]. Even though a huge volume of data was produced, its use was neither cheap nor accurate. Therefore, the clustered regularly interspaced short palindromic repeats (CRISPR) system was evidenced to be the next step in genome engineering tools. CRISPR-associated protein 9 (Cas9)-mediated genetic perturbation is simple, precise and highly efficient, empowering researchers to apply this method to immortalized cancerous cell lines, primary cells derived from mouse and human origins, xenografts, induced pluripotent stem cells, organoid cultures, as well as the generation of genetically engineered animal models. In this review, we assess the development of the CRISPR system and its therapeutic applications to a wide range of complex diseases (particularly distinct tumors), aiming at personalized therapy. Special emphasis is given to organoids and CRISPR screens in the design of innovative therapeutic approaches. Overall, the CRISPR system is regarded as an eminent genome engineering tool in therapeutics. We envision a new era in cancer biology during which the CRISPR-based genome engineering toolbox will serve as the fundamental conduit between the bench and the bedside; nonetheless, certain obstacles need to be addressed, such as the eradication of side-effects, maximization of efficiency, the assurance of delivery and the elimination of immunogenicity.

Genetically­modified stem cells in treatment of human diseases: Tissue kallikrein (KLK1)­based targeted therapy (Review).

The tissue kallikrein­kinin system (KKS) is an endogenous multiprotein metabolic cascade which is implicated in the homeostasis of the cardiovascular, renal and central nervous system. Human tissue kallikrein (KLK1) is a serine protease, component of the KKS that has been demonstrated to exert pleiotropic beneficial effects in protection from tissue injury through its anti­inflammatory, anti­apoptotic, anti­fibrotic and anti­oxidative actions. Mesenchymal stem cells (MSCs) or endothelial progenitor cells (EPCs) constitute populations of well­characterized, readily obtainable multipotent cells with special immunomodulatory, migratory and paracrine properties rendering them appealing potential therapeutics in experimental animal models of various diseases. Genetic modification enhances their inherent properties. MSCs or EPCs are competent cellular vehicles for drug and/or gene delivery in the targeted treatment of diseases. KLK1 gene delivery using adenoviral vectors or KLK1 protein infusion into injured tissues of animal models has provided particularly encouraging results in attenuating or reversing myocardial, renal and cerebrovascular ischemic phenotype and tissue damage, thus paving the way for the administration of genetically modified MSCs or EPCs with the human tissue KLK1 gene. Engraftment of KLK1­modified MSCs and/or KLK1­modified EPCs resulted in advanced beneficial outcome regarding heart and kidney protection and recovery from ischemic insults. Collectively, findings from pre­clinical studies raise the possibility that tissue KLK1 may be a novel future therapeutic target in the treatment of a wide range of cardiovascular, cerebrovascular and renal disorders.

Role of the CRISPR system in controlling gene transcription and monitoring cell fate (Review).

Even though the accrual of transcripts is implicated in distinct disease states, our knowledge regarding their functional role remains obscure. The CRISPR system has surged at the forefront of genome engineering tools in the field of RNA modulation. In the present review, we discuss some exciting applications of the CRISPR system, including the manipulation of RNA sequences, the visualization of chromosomal loci in living cells and the modulation of transcription. The CRISPR system has been documented to be very reliable and specific in altering gene expression, via leveraging inactive catalytically dead CRISPR-associated protein 9 (Cas9). In the present review, the CRISPR system is presented as an eminent tool for the meticulous analysis of gene regulation, loci mapping and complex pathways.

Homeobox Gene Involvement in Normal Hematopoiesis and in the Pathogenesis of Childhood Leukemias.

Homeobox (HOX) genes are a superfamily of highly conserved genes with essential functions in many aspects of mammalian development. Their expression is tightly regulated throughout the duration of definitive hematopoiesis, so the pathogenetic mechanism that leads to leukemia suggests that malignant transformation is directly intertwined with the deregulation of HOX gene expression. Even though HOX gene involvement has been reviewed extensively in adult leukemias, childhood leukemias have received much less attention and mainly in the context of leukemias harboring MLL (mixed-lineage leukemia) gene translocations. In recent years, scientific evidence has highlighted HOX gene involvement in the development of other subtypes of childhood leukemias and added HOX gene family members that were previously unrelated to the pathogenesis of childhood leukemia. This has significant implications when considering both the risk stratification of pediatric patients and potential targets for successful therapy. Through the identification of HOX target genes, their resulting interactions, and the cognate signaling pathways, we hope to gain a better understanding of the molecular mechanism(s) underlying the ectopic activation of these genes in childhood leukemias and subsequently to reveal new molecular targets for successful therapy in cases of poor prognosis or resistant disease.

The Ideological Frame of the Genetic Basis of Cancer: The Important Role of miRNAs.

The elucidation of the genetic basis of cancer is the result of the research conducted since the beginning of the previous century, which peaked during the decades of 1960s and 1970s. It has been achieved through two different but convergent routes: the first includes the study of oncogenic viruses in rodents and birds and the second includes the use of chemical carcinogens in cells or in animal model systems (mice). Within this framework, the identification of genes that present mutations, alterations in expression levels, and epigenetic modifications has been facilitated through the development of animal carcinogenesis models. One of these models is the well-characterized mouse multistage skin cancer system discussed in this review. In addition, recent evidence shows the great significance that cancer stem cells seem to have in the emergence and progression of carcinogenesis. Finally, herein we discuss the critical role that miRNAs have emerged to play in cancer progression. miRNAs emerged as molecules with an impact on most cancer-related cellular processes, involving cell proliferation, cell death (apoptosis), angiogenesis, migration/motility, and rearrangement of the cytoskeleton. Their discovery has given rise to studies with a focus on miRNAs as key players in crucial oncogenesis-related processes and thus as potential targets in cancer therapeutics.

Vascular Complications Following Transradial and Transulnar Coronary Angiography in 1600 Consecutive Patients.

BACKGROUND: Major, noncoronary complications are rarely encountered following transradial coronary procedures. METHODS AND RESULTS: Among 1600 prospectively studied patients with complete follow-up, 7 patients experienced major complications following coronary forearm procedures corresponding to an incidence of 0.44%. We found inadvertent symptomatic intramyocardial contrast medium injection, 2 cases with compartment syndrome of which 1 was managed surgically, exertional hand ischemia due to radial artery occlusion, a large ulnar artery pseudoaneurysm, an ulnar arteriovenous fistula, and 1 critical hand ischemia due to late occlusion of the distal brachial artery. CONCLUSIONS: Although infrequent, surveillance for major complications should be encouraged after forearm coronary procedures.

A comparison of low versus standard heparin dose for prevention of forearm artery occlusion after 5 French coronary angiography.

BACKGROUND: Radial artery occlusion (RAO) remains the Achilles' heel of transradial coronary procedures. Standard over lower systemic anticoagulation levels are believed to reduce RAO rates but this is ill-supported by scientific evidence. We compared whether standard in comparison with less intensive anticoagulation was superior in preventing vessel closure. METHODS AND RESULTS: The two arms of this analysis included 731 pooled patients with the same inclusion and exclusion criteria. We assessed forearm arterial access site occlusion rate by unfractionated heparin (UFH) dose in an individual participant data meta-analysis of this randomized study and of consecutive eligible patients from our previous trial. We randomized 308 consecutive patients undergoing transradial coronary angiography with 5 French (5 Fr) catheters without need to crossover to receive 2500 or 5000 UFH units. The primary end-point was the ultrasonographically determined vessel occlusion rate. Incident RAOs in the randomized arm were 15.9% vs. 14%, in the low and standard UFH dose, respectively (p=0.7). Corresponding figures for forearm arterial occlusion rates in the pooled population were 13.0% vs. 9.9% (relative risk: 1.3, 95% confidence interval - CI: 0.88-1.98; p=0.2). Procedural and fluoroscopy duration was less than 15 and 3 min, respectively. The mean UFH dose difference was 3.52 (95% CI: -0.45 to 7.49) units per kilo body weight between occluded (n=84) and patent forearm arteries (n=647); (p=0.053). CONCLUSIONS: Incident forearm arterial occlusions were high despite using 5 Fr catheters for a short-lasting procedure. Systemic anticoagulation with standard over lower UFH dose did not reduce the frequency of RAOs after coronary angiography.

Progression of mouse skin carcinogenesis is associated with increased ERα levels and is repressed by a dominant negative form of ERα.

Estrogen receptors (ER), namely ERα and ERß, are hormone-activated transcription factors with an important role in carcinogenesis. In the present study, we aimed at elucidating the implication of ERα in skin cancer, using chemically-induced mouse skin tumours, as well as cell lines representing distinct stages of mouse skin oncogenesis. First, using immunohistochemical staining we showed that ERα is markedly increased in aggressive mouse skin tumours in vivo as compared to the papilloma tumours, whereas ERß levels are low and become even lower in the aggressive spindle tumours of carcinogen-treated mice. Then, using the multistage mouse skin carcinogenesis model, we showed that ERα gradually increases during promotion and progression stages of mouse skin carcinogenesis, peaking at the most aggressive stage, whereas ERß levels only slightly change throughout skin carcinogenesis. Stable transfection of the aggressive, spindle CarB cells with a dominant negative form of ERα (dnERα) resulted in reduced ERα levels and reduced binding to estrogen responsive elements (ERE)-containing sequences. We characterized two highly conserved EREs on the mouse ERα promoter through which dnERα decreased endogenous ERα levels. The dnERα-transfected CarB cells presented altered protein levels of cytoskeletal and cell adhesion molecules, slower growth rate and impaired anchorage-independent growth in vitro, whereas they gave smaller tumours with extended latency period of tumour onset in vivo. Our findings suggest an implication of ERα in the aggressiveness of spindle mouse skin cancer cells, possibly through regulation of genes affecting cell shape and adhesion, and they also provide hints for the effective targeting of spindle cancer cells by dnERα.

Misdirected antibody responses against an N-terminal epitope on human rhinovirus VP1 as explanation for recurrent RV infections.

Rhinoviruses (RVs) are the primary cause of upper respiratory tract infections, generally known as the common cold. Moreover, RV infections can trigger severe exacerbations of asthma and chronic obstructive pulmonary disease (COPD). We expressed the 4 major RV capsid proteins, VP1-VP4, in Escherichia coli and used these proteins as well as recombinant and synthetic VP1 fragments to study and map antibody responses in RV-infected humans. VP1, which on infection binds to ICAM 1, was identified as a major target for the memory immune response, residing in the IgG1 subclass and IgA class. Interestingly, this response was mainly directed against an N-terminal 20 mer peptide in VP1, P1a, which becomes exposed on intact RV only when it docks to its receptor ICAM 1. Molecular modeling using the 3-dimensional RV capsid structures revealed that P1a was localized inside the capsid and outside the areas involved in receptor binding or RV neutralization. Our results suggest misdirection of antibody responses against a nonprotective epitope as a mechanism how RV escapes immunity and causes recurrent infections. Based on these findings, it may be possible to design vaccines against RV infections and RV-induced respiratory diseases.