Functional and molecular effects of TNF-α on human iPSC-derived cardiomyocytes

SERCA2a dysfunction in the pathophysiology of heart failure with preserved ejection fraction: a direct role is yet to be established

With rising incidence, mortality and limited therapeutic options, heart failure with preserved ejection fraction (HFpEF) remains one of the most important topics in cardiovascular medicine today. Characterised by left ventricular diastolic dysfunction partially due to impaired Ca2+ homeostasis, one ion channel in particular, SarcoEndoplasmic Reticulum Ca2+-ATPase (SERCA2a), may play a significant role in its pathophysiology. A better understanding of the complex mechanisms interplaying to contribute to SERCA2a dysfunction will help develop treatments targeting it and thus address the growing clinical challenge HFpEF poses. This review examines the conflicting evidence present for changes in SERCA2a expression and activity in HFpEF, explores potential underlying mechanisms, and finally evaluates the drug and gene therapy trials targeting SERCA2a in heart failure. Recent positive results from trials involving widely used anti-diabetic agents such as sodium-glucose co-transporter protein 2 inhibitors (SGLT2i) and glucagon-like peptide-1 (GLP-1) agonists offer advancement in HFpEF management. The potential interplay between these agents and SERCA2a regulation presents a novel angle that could open new avenues for modulating diastolic function; however, the mechanistic research in this emerging field is limited. Overall, the direct role of SERCA2a dysfunction in HFpEF remains undetermined, highlighting the need for well-designed pre-clinical studies and robust clinical trials.

Targeting the Ca2+ signaling toolkit as an alternative strategy to mitigate SARS-CoV-2-induced cardiovascular adverse events

Ca2+ signaling events are essential for maintaining cardiovascular health, regulating critical functions in both endothelial and cardiac cells. SARS-CoV-2 infection impinges this delicate balance, leading to severe cardiovascular complications. SARS-CoV-2 binds to the ACE2 receptor on endothelial and cardiomyocyte surfaces, triggering abnormal increases in intracellular Ca2+ levels that promote endothelial dysfunction, inflammation, and hypercoagulation. In endothelial cells, this dysregulation activates a pro-inflammatory state and compromises vascular integrity. In cardiomyocytes, SARS-CoV-2-induced Ca2+ imbalances contribute to arrhythmias and heart failure by promoting abnormal Ca2+ cycling and energy metabolism disruptions. Additionally, the cytokine storm associated with COVID-19 amplifies these effects by further altering Ca2+ handling, enhancing inflammatory responses, and promoting thrombosis. Targeting Ca2+ channels, particularly endolysosomal two-pore channels, represents a promising therapeutic approach to counteract SARS-CoV-2's effects on Ca2+ dynamics. Several FDA-approved drugs that modulate Ca2+ signaling could be repurposed to prevent viral entry and mitigate cardiovascular damage. Understanding these Ca2+-related mechanisms offers valuable insights for developing treatments to reduce cardiovascular risk in COVID-19 and potentially future viral infections impacting the cardiovascular system.

Direct effects of prolonged TNF-α and IL-6 exposure on neural activity in human iPSC-derived neuron-astrocyte co-cultures

Cognitive impairment is one of the many symptoms reported by individuals suffering from long-COVID and other post-viral infection disorders such as myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). A common factor among these conditions is a sustained immune response and increased levels of inflammatory cytokines. Tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) are two such cytokines that are elevated in patients diagnosed with long-COVID and ME/CFS. In this study, we characterized the changes in neural functionality, secreted cytokine profiles, and gene expression in co-cultures of human iPSC-derived neurons and primary astrocytes in response to prolonged exposure to TNF-α and IL-6. We found that exposure to TNF-α produced both a concentration-independent and concentration-dependent response in neural activity. Burst duration was significantly reduced within a few days of exposure regardless of concentration (1 pg/mL - 100 ng/mL) but returned to baseline after 7 days. Treatment with low concentrations of TNF-α (e.g., 1 and 25 pg/mL) did not lead to changes in the secreted cytokine profile or gene expression but still resulted in significant changes to electrophysiological features such as interspike interval and burst duration. Conversely, treatment with high concentrations of TNF-α (e.g., 10 and 100 ng/mL) led to reduced spiking activity, which may be correlated to changes in neural health, gene expression, and increases in inflammatory cytokine secretion (e.g., IL-1β, IL-4, and CXCL-10) that were observed at higher TNF-α concentrations. Prolonged exposure to IL-6 led to changes in bursting features, with significant reduction in the number of spikes in bursts across a wide range of treatment concentrations (i.e., 1 pg/mL-10 ng/mL). In combination, the addition of IL-6 appears to counteract the changes to neural function induced by low concentrations of TNF-α, while at high concentrations of TNF-α the addition of IL-6 had little to no effect. Conversely, the changes to electrophysiological features induced by IL-6 were lost when the cultures were co-stimulated with TNF-α regardless of the concentration, suggesting that TNF-α may play a more pronounced role in altering neural function. These results indicate that increased concentrations of key inflammatory cytokines associated with long-COVID can directly impact neural function and may be a component of the cognitive impairment associated with long-COVID and other post-viral infection disorders.

Hypoxia and TNF-alpha modulate extracellular vesicle release from human induced pluripotent stem cell-derived cardiomyocytes

Extracellular vesicles (EVs) have emerged as important mediators of intercellular communication in the heart under homeostatic and pathological conditions, such as myocardial infarction (MI). However, the basic mechanisms driving cardiomyocyte-derived EV (CM-EV) production following stress are poorly understood. In this study, we generated human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) that express NanoLuc-tetraspanin reporters. These modified hiPSC-CMs allow for quantification of tetraspanin-positive CM-EV secretion from small numbers of cells without the need for time-consuming EV isolation techniques. We subjected these cells to a panel of small molecules to study their effect on CM-EV biogenesis and secretion under basal and stress-associated conditions. We observed that EV biogenesis is context-dependent in hiPSC-CMs. Nutrient starvation decreases CM-EV secretion while hypoxia increases the production of CM-EVs in a nSmase2-dependent manner. Moreover, the inflammatory cytokine TNF-α increased CM-EV secretion through a process involving NLRP3 inflammasome activation and mTOR signalling. Here, we detailed for the first time the regulatory mechanisms of EV biogenesis in hiPSC-CMs upon MI-associated stressors.

Pathophysiological Mechanisms of Psychosis-Induced Atrial Fibrillation: The Links between Mental Disorder and Arrhythmia

Atrial fibrillation (AF) is a common phenomenon of sustained arrhythmia leading to heart failure or stroke. Patients with mental disorders (MD), particularly schizophrenia and bipolar disorder, are at a high risk of AF triggered by the dysregulation of the autonomic nervous system, atrial stretch, oxidative stress, inflammation, and electrical or structural remodeling. Moreover, pathophysiological mechanisms underlying MD may also contribute to the genesis of AF. An overactivated hypothalamic-pituitary-adrenal axis, aberrant renin-angiotensin-aldosterone system, abnormal serotonin signaling, disturbed sleep, and genetic/epigenetic factors can adversely alter atrial electrophysiology and structural substrates, leading to the development of AF. In this review, we provide an update of our collective knowledge of the pathophysiological and molecular mechanisms that link MD and AF. Targeting the pathogenic mechanisms of MD-specific AF may facilitate the development of therapeutics that mitigate AF and cardiovascular mortality in this patient population.

Pathophysiological mechanisms underlying increased circulating cardiac troponin in noncardiac surgery: a narrative review

Assay-specific increases in circulating cardiac troponin are observed in 20-40% of patients after noncardiac surgery, depending on patient age, type of surgery, and comorbidities. Increased cardiac troponin is consistently associated with excess morbidity and mortality after noncardiac surgery. Despite these findings, the underlying mechanisms are unclear. The majority of interventional trials have been designed on the premise that ischaemic cardiac disease drives elevated perioperative cardiac troponin concentrations. We consider data showing that elevated circulating cardiac troponin after surgery could be a nonspecific marker of cardiomyocyte stress. Elevated concentrations of circulating cardiac troponin could reflect coordinated pathological processes underpinning organ injury that are not necessarily caused by ischaemia. Laboratory studies suggest that matching of coronary artery autoregulation and myocardial perfusion-contraction coupling limit the impact of systemic haemodynamic changes in the myocardium, and that type 2 ischaemia might not be the likeliest explanation for cardiac troponin elevation in noncardiac surgery. The perioperative period triggers multiple pathological mechanisms that might cause cardiac troponin to cross the sarcolemma. A two-hit model involving two or more triggers including systemic inflammation, haemodynamic strain, adrenergic stress, and autonomic dysfunction might exacerbate or initiate acute myocardial injury directly in the absence of cell death. Consideration of these diverse mechanisms is pivotal for the design and interpretation of interventional perioperative trials.

Myoglobin modulates the Hippo pathway to promote cardiomyocyte differentiation

The endogenous mechanisms that propagate cardiomyocyte differentiation and prevent de-differentiation remain unclear. While the expression of the heme protein myoglobin increases by over 50% during cardiomyocyte differentiation, a role for myoglobin in regulating cardiomyocyte differentiation has not been tested. Here, we show that deletion of myoglobin in cardiomyocyte models decreases the gene expression of differentiation markers and stimulates cellular proliferation, consistent with cardiomyocyte de-differentiation. Mechanistically, the heme prosthetic group of myoglobin catalyzes the oxidation of the Hippo pathway kinase LATS1, resulting in phosphorylation and inactivation of yes-associated protein (YAP). In vivo, myoglobin-deficient zebrafish hearts show YAP dephosphorylation and accelerated cardiac regeneration after apical injury. Similarly, myoglobin knockdown in neonatal murine hearts shows increased YAP dephosphorylation and cardiomyocyte cycling. These data demonstrate a novel role for myoglobin as an endogenous driver of cardiomyocyte differentiation and highlight myoglobin as a potential target to enhance cardiac development and improve cardiac repair and regeneration.

Exploring the mechanism of curcumin in the treatment of doxorubicin-induced cardiotoxicity based on network pharmacology and molecular docking technology

Doxorubicin (DOX) is one of the most effective chemotherapeutic agents. However, the nonselective effect leads to serious cardiotoxicity risk in clinical use. Curcumin is a well-known dietary polyphenol that showed a protective effect against the cardiotoxic effect of DOX. This study aimed to assess the role of curcumin in protection against DOX-induced cardiotoxicity. Potential compound and disease targets were obtained from relevant databases, and common targets were screened. Protein-protein interaction (PPI) was used to predict the core targets. Gene ontology (GO) bioprocess analysis and Kyoto encyclopedia of genes and genome enrichment analysis enriched the possible biological processes (BP), cellular components, molecular function, and signaling pathways involved. Finally, the binding of curcumin to target proteins was evaluated through molecular docking. The docking score verified the reliability of the prediction results. In total, 205 curcumin and 700 disease targets were identified. A topological analysis of the PPI network revealed 10 core targets including TP53, tumor necrosis factor-alpha (TNF), AKT1, vascular endothelial growth factor A (VEGFA), prostaglandin-endoperoxide synthase 2 (PTGS2), signal transducer and activator of the transcription 3 (STAT3), HIF1A, MYC, epidermal growth factor receptor (EGFR), and CASP3 (Caspase-3). Furthermore, the enrichment analyses indicated that the effects of curcumin were mediated by genes related to oxidation, inflammation, toxification, cell proliferation, migration, apoptosis, wounding, metabolism, proteolysis, and the signaling pathway of calcium (Ca2+). Molecular docking showed that curcumin could bind with the target proteins with strong molecular force, exhibiting good docking activity. Curcumin has a multi-cardioprotective effect by modulating the core targets' expression in DOX-induced cardiotoxicity. This study elucidated the key target proteins and provided a theoretical basis for further exploring curcumin in the prevention and treatment of DOX-induced cardiotoxicity.

Progranulin-deficient macrophages cause cardiotoxicity under hypoxic conditions

Myocardial infarction (MI) induces structural and electrical cardiac remodeling in response to ischemic insult, causing lethal arrhythmias and sudden death. Progranulin (PGRN) is a glycoprotein mainly expressed in macrophages that modulates the immune responses. In this study, we investigated the direct influence of PGRN knockout (Grn-/-) macrophages on post-MI pathophysiology. An MI mouse model was established by ligating the left coronary artery for RNA sequencing and electrocardiographic analysis. Bone marrow-derived macrophages (BMDMs) were injected into mice and supernatant was collected for the measurement of reactive oxygen species (ROS) levels and extracellular flux analysis. Administration of Grn-/- BMDMs prolonged the QT intervals in the MI mouse model. Moreover, genes highly expressed in macrophages were upregulated in Grn-/- heart after MI. Post-hypoxic supernatant of Grn-/- BMDMs increased the oxygen-glucose deprivation-induced cardiomyocyte death. Grn-/- BMDMs exhibited increased ROS production, oxygen consumption, and extracellular acidification under hypoxia and inflammatory conditions. These findings suggest that PGRN deficiency causes cardiotoxicity via secretory components of macrophages that exhibit metabolic abnormalities under hypoxia.

Metoprolol disrupts inflammatory response of human cardiomyocytes via β-arrestin2 biased agonism and NF-κB signaling modulation

AIMS

Recent evidence supports non-class cardioprotective effects of metoprolol against neutrophil-mediated ischemia-reperfusion injury during exacerbated inflammation. Whether metoprolol exerts direct anti-inflammatory effect on cardiomyocytes is unknown. Accordingly, we aimed to investigate the direct anti-inflammatory effects of metoprolol in a cellular model of human induced pluripotent stem cell-derived cardiomyocytes (hiCMs) and to explore the role of β-arrestin2 (β-ARR2) biased agonism signaling pathway.

METHODS AND RESULTS

hiCMs were treated with TNF-α for 24 h, followed by 4-hour treatment with metoprolol or esmolol. Electrical response of hiCMs to β1-selective blockade was assessed by microelectrode arrays technology. The effect on inflammatory and adhesion molecule expression was evaluated in wild-type and β-ARR2 silenced hiCMs. To silence β-ARR2 expression, hiCMs were transfected with a specific small interfering RNA targeting β-ARR2 mRNA and preventing its translation. TNF-α stimulation boosted the expression of IκB, NF-κB, IL1β, IL6, and VCAM1 in hiCMs. TNF-α-treated hiCMs showed similar physiological responses to metoprolol and esmolol, with no difference in field potential duration and beat period recorded. Adding metoprolol significantly decreased inflammatory response patterns in wild-type hiCMs by dampening TNF-α induced expression of NF-κB, IL1β, and IL6, but not in β-ARR2-knockout hiCMs. A similar response was not observed in presence of β1-selective blockade with esmolol.

CONCLUSIONS

Metoprolol exerts a non-class direct anti-inflammatory effect on hi-CMs. β1-selective blockade with metoprolol disrupts inflammatory responses induced by TNF-α and induces significant inhibition of NF-κB signaling cascade via β-ARR2 biased agonism. If confirmed at clinical level, metoprolol could be tested and repurposed to treat cardiac inflammatory disorders.

Equine induced pluripotent stem cells are responsive to inflammatory cytokines before and after differentiation into musculoskeletal cell types

Persistent inflammation is associated with the poor regeneration of musculoskeletal tissues. Embryonic stem cells (ESCs) have an attenuated response to inflammatory cytokines, but there are mixed reports on the response of induced pluripotent stem cells (iPSCs) to inflammation. Horses provide a relevant large animal model for studying musculoskeletal tissue diseases and the testing of novel therapies. The aim of this study was to determine if equine iPSCs are responsive to the inflammatory cytokines IL-1β, TNFα and IFN-γ in their undifferentiated state, or following differentiation into tendon and cartilage-like cells. We demonstrated that in undifferentiated iPSCs, the cytokines induce NF-κB P65 and STAT1 nuclear translocation which leads to cell death, decreased OCT4 expression and increased expression of inflammatory genes. Following differentiation towards cartilage-like cells exposure to the cytokines resulted in STAT1 nuclear translocation, changes in cartilage gene expression and increased expression of matrix metalloproteinases (MMPs) and inflammatory genes. Exposure of iPSC-derived tendon-like cells to the cytokines resulted nuclear translocation of NF-κB P65 and STAT1, altered tendon gene expression, increased MMP expression and increased expression of inflammatory genes. Equine iPSCs are therefore capable of responding to inflammatory stimulation and this may have relevance for their future clinical application.

TNF-α Preconditioning Promotes a Proangiogenic Phenotype in hiPSC-Derived Vascular Smooth Muscle Cells

Introduction

hiPSC-VSMCs have been suggested as therapeutic agents for wound healing and revascularization through the secretion of proangiogenic factors. However, methods of increasing cell paracrine secretion and survivability have thus far yielded inconsistent results. This study investigates the effect of pre-conditioning of hiPSC-VSMCs with TNF-α and their integration into 3D collagen scaffolds on cellular viability and secretome.

Methods

hiPSC-VSMCs were dual-plated in a 2D environment. TNF-α was introduced to one plate. Following incubation, cells from each plate were divided and added to type-I collagen scaffolds. TNF-α was introduced to two sets of scaffolds, one from each 2D plate. Following incubation, scaffolds were harvested for their media, tested for cell survivability, cytotoxicity, and imaged. Intra-media VEGF and bFGF levels were evaluated using ELISA testing.

Results

hiPSC-VSMCs exposed to TNF-α during collagen scaffold proliferation and preconditioning showed an increase in cell viability and less cytotoxicity compared to non-exposed cells and solely-preconditioned cells. Significant increases in bFGF expression were found in pre-conditioned cell groups with further increases found in cells subsequently exposed during intra-scaffold conditioning. A significant increase in VEGF expression was found in cell groups exposed during both pre-conditioning and intra-scaffold conditioning. Fibroblasts treated with any conditioned media demonstrated increased migration potential.

Conclusions

Conditioning hiPSC-VSMCs embedded in scaffolds with TNF-α improves cellular viability and increases the secretion of paracrine factors necessary for wound healing mechanisms such as migration.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12195-023-00764-0.

Toxoplasma gondii microneme protein MIC3 induces macrophage TNF-α production and Ly6C expression via TLR11/MyD88 pathway

Toxoplasma gondii is the most successful parasite worldwide. It is of great interest to understand how T. gondii induce different immune responses in different hosts. In this study, we found that a peptide of T. gondii microneme protein MIC3 induced TNF-α production, NF-κB phosphorylation, iNOS transcription and Ly6C expression in mouse macrophage RAW264.7 cells. MyD88 inhibition, small interfering RNA against Tlr11 and CRISPR/Cas9-mediated knock-out of Tlr11 all reduced MIC3-induced TNF-α production, NF-κB phosphorylation, iNOS transcription and Ly6C expression. Additionally, we determined the location of MIC3 peptide in mouse macrophages using immunofluorescence. MIC3 could both adhere to the cell membrane of mouse macrophages and enter the cells. These results suggest that MIC3 triggered the immune responses in mouse macrophages via TLR11/MyD88/NF-κB pathway. It is known that human macrophages lacking TLR11. We predicted that the immune responses induced by MIC3 in human macrophages were significantly different from those in mouse macrophages. As expected, MIC3 peptide failed to induce TNF-α expression, iNOS expression and NF-κB phosphorylation in human THP-1 derived macrophages. MIC3 induced macrophage immune responses via TLR11. Intriguingly, the amino acid sequence of MIC3 is completely different from the well-known TLR11 ligand profilin, which generates a potent IL-12p40, TNF-α and IL-6 response. In marked contrast to profilin, MIC3 could not induce IL-12p40 expression in both mouse RAW264.7 cells and human THP-1 derived macrophages. Furthermore, the simulated tertiary structure of MIC3 peptide shows poor similarity with the crystal structure of profilin, suggesting that MIC3 might be a different ligand from profilin. These findings about MIC3 and TLR11 will provide us with important insights into the pathogenesis of toxoplasmosis and coevolution during host-parasite interaction.

DAMPs Released from Proinflammatory Macrophages Induce Inflammation in Cardiomyocytes via Activation of TLR4 and TNFR

Cardiac dysfunction is a life-threatening complication in sepsis. Upon infection and cardiac stress, the cardiac macrophage population expands. Recruited macrophages exhibit a predominantly proinflammatory phenotype and release danger-associated molecular patterns (DAMPs) that contribute to cardiac dysfunction. However, the underlying pathomechanisms are highly complex and not fully understood. Here, we utilized an indirect macrophage-cardiomyocyte co-culture model to study the effects of proinflammatory macrophages on the activation of different cardiac receptors (TLR3, TLR4, and TNFR) and their role in cardiac inflammation and caspase-3/7 activation. The stimulation of cardiomyocytes with conditioned medium of LPS-stimulated macrophages resulted in elevated IL-6 protein concentrations and relative IL-6 and TNFα mRNA levels. Conditioned medium from LPS-stimulated macrophages also induced NFκB translocation and increased caspase-3/7 activation in cardiomyocytes. Analyzing the role of different cardiac receptors, we found that TLR4 and TNFR inhibition reduces cardiac inflammation and that the inhibition of TNFR prevents NFκB translocation into the nuclei of cardiomyocytes, induced by exposure to conditioned medium of proinflammatory macrophages. Moreover, we demonstrated that TLR3 inhibition reduces macrophage-mediated caspase-3/7 activation. Our results suggest that the immune response of macrophages under inflammatory conditions leads to the release of DAMPs, such as eRNA and cytokines, which in turn induce cardiomyocyte dysfunction. Thus, the data obtained in this study contribute to a better understanding of the pathophysiological mechanisms of cardiac dysfunction.

Genetic Association between Polymorphisms of Interleukin-32 and Dilated Cardiomyopathy in Chinese Han Population

Background

Dilated cardiomyopathy is a primary myocardial disease and one of the critical causes of heart failure. It is the most common indication for heart transplantation worldwide, and most idiopathic dilated cardiomyopathies are sporadic and multifactorial. Evidence has supported that several inflammatory cytokines and immune responses are involved in its pathological process. Interleukin-32 is a proinflammatory cytokine and is elevated during the worsening cardiac function. Herein, we evaluated the correlation between interleukin-32 gene polymorphisms (rs12934561 and rs28372698) and the susceptibility to dilated cardiomyopathy.

Methods

We enrolled 418 dilated cardiomyopathy patients and 437 healthy controls. The polymerase chain reaction-restriction fragment length polymorphism method was used for genotyping the two single-nucleotide polymorphisms (SNPs), and SPSS software was used for statistical analyses.

Results

The C allele and CC genotype frequencies of rs12934561 were remarkably elevated in dilated cardiomyopathy patients compared to controls (both P < 0.001). The A allele and AA genotype frequencies of rs28372698 significantly decreased in dilated cardiomyopathy patients (P = 0.004 and P = 0.02, respectively). Compared to TT/TC genotype carriers of rs12934561, CC homozygotes presented an increased risk of dilated cardiomyopathy when the left ventricular ejection fraction no more than 30% (P = 0.02).

Conclusions

The IL-32 gene polymorphisms might implicate in DCM risk in the Chinese Han population, and rs12934561 could be a potential forecasting factor for screening high-risk population for DCM.

Distress-Mediated Remodeling of Cardiac Connexin-43 in a Novel Cell Model for Arrhythmogenic Heart Diseases

Gap junctions and their expression pattern are essential to robust function of intercellular communication and electrical propagation in cardiomyocytes. In healthy myocytes, the main cardiac gap junction protein connexin-43 (Cx43) is located at the intercalated disc providing a clear direction of signal spreading across the cardiac tissue. Dislocation of Cx43 to lateral membranes has been detected in numerous cardiac diseases leading to slowed conduction and high propensity for the development of arrhythmias. At the cellular level, arrhythmogenic diseases are associated with elevated levels of oxidative distress and gap junction remodeling affecting especially the amount and sarcolemmal distribution of Cx43 expression. So far, a mechanistic link between sustained oxidative distress and altered Cx43 expression has not yet been identified. Here, we propose a novel cell model based on murine induced-pluripotent stem cell-derived cardiomyocytes to investigate subcellular signaling pathways linking cardiomyocyte distress with gap junction remodeling. We tested the new hypothesis that chronic distress, induced by rapid pacing, leads to increased reactive oxygen species, which promotes expression of a micro-RNA, miR-1, specific for the control of Cx43. Our data demonstrate that Cx43 expression is highly sensitive to oxidative distress, leading to reduced expression. This effect can be efficiently prevented by the glutathione peroxidase mimetic ebselen. Moreover, Cx43 expression is tightly regulated by miR-1, which is activated by tachypacing-induced oxidative distress. In light of the high arrhythmogenic potential of altered Cx43 expression, we propose miR-1 as a novel target for pharmacological interventions to prevent the maladaptive remodeling processes during chronic distress in the heart.

SARS-CoV-2 infection in cardiovascular disease: Unmet need of stem cell models

This review aims to summarise new approaches in SARS-CoV-2-related research in cardiology. We provide a head-to-head comparison of models, such as animal research and human pluripotent stem cells, to investigate the pathomechanisms of COVID-19 and find an efficient therapy. In vivo methods were useful for studying systemic processes of the disease; however, due to differences in animal and human biology, the clinical translation of the results remains a complex task. In vitro stem cell research makes cellular events more observable and effective for finding new drugs and therapies for COVID-19, including the use of stem cells. Furthermore, multicellular 3D organoids even make it possible to observe the effects of drugs to treat SARS-CoV-2 infection in human organ models.

Space microgravity improves proliferation of human iPSC-derived cardiomyocytes

In microgravity, cells undergo profound changes in their properties. However, how human cardiac progenitors respond to space microgravity is unknown. In this study, we evaluated the effect of space microgravity on differentiation of human induced pluripotent stem cell (hiPSC)-derived cardiac progenitors compared with 1G cultures on the International Space Station (ISS). Cryopreserved 3D cardiac progenitors were cultured for 3 weeks on the ISS. Compared with 1G cultures, the microgravity cultures had 3-fold larger sphere sizes, 20-fold higher counts of nuclei, and increased expression of proliferation markers. Highly enriched cardiomyocytes generated in space microgravity showed improved Ca²⁺ handling and increased expression of contraction-associated genes. Short-term exposure (3 days) of cardiac progenitors to space microgravity upregulated genes involved in cell proliferation, survival, cardiac differentiation, and contraction, consistent with improved microgravity cultures at the late stage. These results indicate that space microgravity increased proliferation of hiPSC-cardiomyocytes, which had appropriate structure and function.

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Cryopreserved 3D hiPSC-cardiac progenitors differentiated efficiently in space

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Microgravity cultures had increased sphere sizes and cellular proliferation

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Beating cardiomyocytes in microgravity cultures had improved Ca²⁺ handling

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Microgravity cultures had upregulated genes in cardiac contraction

Effect of Alpha-Lipoic Acid on Rat Ventricles and Atria under LPS-Induced Oxidative Stress

Alpha-lipoic acid (α-LA) is a disulfide compound and one of the most effective antioxidants. Many studies have indicated positive effects of α-LA in the prevention of pathologic conditions mediated by oxidative stress, such as cardiovascular diseases. However, the therapeutic potential of α-LA for the heart has not been explored with regards to the ventricles and atria. The aim of our study was to evaluate the effects of α-LA on oxidative stress parameters and inflammation in the ventricles and atria of the heart in rats under LPS-induced oxidative stress. Wistar rats were divided into 4 groups: I—control (received 2 doses of 0.2 mL of 0.9% NaCl i.v., 0.5 h apart); II—α-LA (received 0.2 mL of 0.9% NaCl and 0.5 h later received α-LA 60 mg/kg b.w. i.v.); III—lipopolysaccharide (LPS) (received 0.2 mL of 0.9% NaCl and 0.5 h later received LPS 30 mg/kg b.w. i.v.); and IV—LPS + LA (received LPS 30 mg/kg b.w. i.v. and 0.5 h later received α-LA 60 mg/kg b.w. i.v.). Five hours later, the rats were euthanized. The hearts were surgically removed and weighed to estimate heart edema. The ventricular and atrium tissue was isolated to measure levels of TNF-α, IL-6, superoxide dismutase (SOD), thiobarbituric acid reactive substances (TBARS), hydrogen peroxide (H₂O₂), total sulfhydryl groups (-SH), total glutathione (tGSH), reduced glutathione (GSH), glutathione disulfide (GSSG), and the GSH/GSSG ratio. LPS significantly increased TNF-α, IL-6, TBARS, and H₂O₂ levels and decreased SOD, -SH groups, tGSH, the GSH/GSSG ratio, and GSH levels in rat ventricles and atria while α-LA administered after the injection of LPS significantly decreased TNF-α, IL-6, TBARS, and H₂O₂ levels. α-LA also increased SOD and -SH group levels and ameliorated the glutathione redox status when compared to the LPS group. Our data suggest that α-LA administration 30 min after LPS infusion may effectively prevent inflammation and oxidative stress in the ventricles and atria.

Cardiac ischemia on-a-chip to investigate cellular and molecular response of myocardial tissue under hypoxia

Tissue engineering has enabled the development of advanced and physiologically relevant models of cardiovascular diseases, with advantages over conventional 2D in vitro assays. We have previously demonstrated development of a heart on-a-chip microfluidic model with mature 3D anisotropic tissue formation that incorporates both stem cell-derived cardiomyocytes and cardiac fibroblasts within a collagen-based hydrogel. Using this platform, we herein present a model of myocardial ischemia on-a-chip, that recapitulates ischemic insult through exposure of mature 3D cardiac tissues to hypoxic environments. We report extensive validation and molecular-level analyses of the model in its ability to recapitulate myocardial ischemia in response to hypoxia, demonstrating the 1) induction of tissue fibrosis through upregulation of contractile fibers, 2) dysregulation in tissue contraction through functional assessment, 3) upregulation of hypoxia-response genes and downregulation of contractile-specific genes through targeted qPCR, and 4) transcriptomic pathway regulation of hypoxic tissues. Further, we investigated the complex response of ischemic myocardial tissues to reperfusion, identifying 5) cell toxicity, 6) sustained contractile irregularities, as well as 7) re-establishment of lactate levels and 8) gene expression, in hypoxic tissues in response to ischemia reperfusion injury.

MicroRNA-181b Serves as a Circulating Biomarker and Regulates Inflammation in Heart Failure

Heart failure (HF) is the typical terminal stage of cardiac diseases involving inflammatory states. The function of microRNAs (miRNAs) in the progress of HF remains poorly understood. In this study, real-time PCR results showed a decreased expression of miRNA-181b (miR-181b) in HF patients compared with healthy individuals. Besides, miR-181b expressions were negatively correlated with hypersensitive C-reactive protein (hsCRP) levels in the serum of HF patients. Receiver operator characteristic (ROC) curve analysis showed that miR-181b was a diagnostic predictor of HF, and the area under the curve was 0.970 (DCM-induced HF group) and 0.962 (ICM-induced HF group). Strikingly, in HF rats induced by isoproterenol (ISO), the expression of miR-181b of heart tissue was suppressed before tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) increase, as revealed by western blot and real-time PCR. Besides, the overexpression of miR-181b also decreased the expression of TNF-α, IL-1β, and IL-6 in lipopolysaccharide- (LPS-) induced neonatal cardiomyocytes. In conclusion, our results revealed that miR-181b might be a potential biomarker for HF and provided a novel target for anti-inflammatory therapy.