Stem Cell-Derived Cardiomyocyte-Like Cells in Myocardial Regeneration

Myocardial infarction results in the significant loss of cardiomyocytes (CMs) due to the ischemic injury following coronary occlusion leading to impaired contractility, fibrosis, and ultimately heart failure. Stem cell therapy emerged as a promising regenerative strategy to replenish the otherwise terminally differentiated CM to restore cardiac function. Multiple strategies have been applied to successfully differentiate diverse stem cell populations into CM-like phenotypes characterized by the expression status of signature biomarkers and observable spontaneous contractions. This article discusses the current understanding and applications of various stem cell phenotypes to drive the differentiation machinery toward CM-like lineage. Impact Statement Ischemic heart disease (IHD) extensively affects a large proportion of the population worldwide. Unfortunately, current treatments for IHD are insufficient to restore cardiac effectiveness and functionality. A growing field in regenerative cardiology explores the potential for stem cell therapy following cardiovascular ischemic episodes. The thorough understanding regarding the potential and shortcomings of translational approaches to drive versatile stem cells to cardiomyocyte lineage paves the way for multiple opportunities for next-generation cardiac management.

Spatial transcriptomic profiling of coronary endothelial cells in SARS-CoV-2 myocarditis

Objectives

Our objective was to examine coronary endothelial and myocardial programming in patients with severe COVID-19 utilizing digital spatial transcriptomics.

Background

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has well-established links to thrombotic and cardiovascular events. Endothelial cell infection was initially proposed to initiate vascular events; however, this paradigm has sparked growing controversy. The significance of myocardial infection also remains unclear.

Methods

Autopsy-derived cardiac tissue from control (n = 4) and COVID-19 (n = 8) patients underwent spatial transcriptomic profiling to assess differential expression patterns in myocardial and coronary vascular tissue. Our approach enabled transcriptional profiling in situ with preserved anatomy and unaltered local SARS-CoV-2 expression. In so doing, we examined the paracrine effect of SARS-CoV-2 infection in cardiac tissue.

Results

We observed heterogeneous myocardial infection that tended to colocalize with CD31 positive cells within coronary capillaries. Despite these differences, COVID-19 patients displayed a uniform and unique myocardial transcriptional profile independent of local viral burden. Segmentation of tissues directly infected with SARS-CoV-2 showed unique, pro-inflammatory expression profiles including upregulated mediators of viral antigen presentation and immune regulation. Infected cell types appeared to primarily be capillary endothelial cells as differentially expressed genes included endothelial cell markers. However, there was limited differential expression within the endothelium of larger coronary vessels.

Conclusion

Our results highlight altered myocardial programming during severe COVID-19 that may in part be associated with capillary endothelial cells. However, similar patterns were not observed in larger vessels, diminishing endotheliitis, and endothelial activation as key drivers of cardiovascular events during COVID-19.

Expression and Change of miRs 145, 221 and 222 in Hypertensive Subjects Treated with Enalapril, Losartan or Olmesartan

miR profile could be associated to CV risk, and also to prognosis/outcome in response to therapeutic approach. We aimed to evaluate if anti-hypertensive drugs enalapril, losartan or olmesartan have effects on monocyte miR profile in essential hypertensives without target organ involvement. For this purpose, 82 hypertensives and 49 controls were included; we evaluated SBP/DBP, lipid profile, glucose, CRP, fibrinogen, arterial stiffness indices (PWV; AIx), and cIMT at baseline (T0) and after 24 weeks of treatment (T1). Subjects with LDL-C ≥ 160 mg/dL, TG ≥ 200 mg/dL, BMI ≥ 30, and other additional CV risk factors were excluded. Patients who were prescribed to receive once-a-day enalapril 20 mg, losartan 100 mg or olmesartan 20 mg were eligible for the study. At T1, we found a significant improvement of SBP (-18.5%), DBP (-18%), HDL-C and LDL-C (+3% and -5.42%), glucose (-2.15%), BMI (-3.23%), fibrinogen (-11%), CRP (-17.5%,), AIx (-49.1%) PWV (-32.2%), and monocyte miR expression (miR-221: -28.4%; miR-222: -36%; miR-145: +41.7%) with respect to baseline. miR profile was compared to control subjects at baseline and at T1. We found some little difference in the behaviour of the three treatments on some variables: olmesartan was the most effective in reducing fibrinogen, DBP, CRP, and AIx (-13.1%, -19.3%, -21.4%, and -56.8%, respectively). Enalapril was the drug more significantly increasing the expression of miR-145. In conclusion, enalapril, losartan and olmesartan are effective in improving mechanical and humoral factors associated to AS and atherogenesis. These drugs appear to be able to modify miRs 221/222 and miR-145 expression in drug-naïve hypertensives, making it closer to that of control subjects; additionally, this provides a good blood pressure compensation, contributing to slow the progression of vascular damage.

Programming of Cell Resistance to Genotoxic and Oxidative Stress

Different organisms, cell types, and even similar cell lines can dramatically differ in resistance to genotoxic stress. This testifies to the wide opportunities for genetic and epigenetic regulation of stress resistance. These opportunities could be used to increase the effectiveness of cancer therapy, develop new varieties of plants and animals, and search for new pharmacological targets to enhance human radioresistance, which can be used for manned deep space expeditions. Based on the comparison of transcriptomic studies in cancer cells, in this review, we propose that there is a high diversity of genetic mechanisms of development of genotoxic stress resistance. This review focused on possibilities and limitations of the regulation of the resistance of normal cells and whole organisms to genotoxic and oxidative stress by the overexpressing of stress-response genes. Moreover, the existing experimental data on the effect of such overexpression on the resistance of cells and organisms to various genotoxic agents has been analyzed and systematized. We suggest that the recent advances in the development of multiplex and highly customizable gene overexpression technology that utilizes the mutant Cas9 protein and the abundance of available data on gene functions and their signal networks open new opportunities for research in this field.

Transcription factor-induced lineage programming of noradrenaline and motor neurons from embryonic stem cells

An important goal in stem cell biology is to develop methods for efficient generation of clinically interesting cell types from relevant stem cell populations. This is particularly challenging for different types of neurons of the central nervous system where hundreds of distinct neuronal cell types are generated during embryonic development. We previously used a strategy based on forced transcription factor expression in embryonic stem cell-derived neural progenitors to generate specific types of neurons, including dopamine and serotonin neurons. Here, we extend these studies and show that noradrenergic neurons can also be generated from pluripotent embryonic stem cells by forced expression of the homeobox transcription factor Phox2b under the signaling influence of fibroblast growth factor 8 (FGF8) and bone morphogenetic proteins. In neural progenitors exposed to FGF8 and sonic hedgehog both Phox2b and the related Phox2a instead promoted the generation of neurons with the characteristics of mid- and hindbrain motor neurons. The efficient generation of these neuron types enabled a comprehensive genome-wide gene expression analysis that provided further validation of the identity of generated cells. Moreover, we also demonstrate that the generated cell types are amenable to drug testing in vitro and we show that variants of the differentiation protocols can be applied to cultures of human pluripotent stem cells for the generation of human noradrenergic and visceral motor neurons. Thus, these studies provide a basis for characterization of yet an additional highly clinically relevant neuronal cell type.