Expression Of Cardiac Markers Research Articles

The hanging‐heart chip: A portable microfluidic device for high‐throughput generation of contractile embryonic stem cell‐derived cardiac spheroids

AbstractStem cell‐derived cardiac spheroids are promising models for cardiac research and drug testing. However, generating contracting cardiac spheroids remains challenging because of the laborious experimental procedure. Here, we present a microfluidic hanging‐heart chip (HH‐chip) that uses a microchannel and flow‐driven system to facilitate cell loading and culture medium replacement operations to reduce the laborious manual handling involved in the generation of a large quantity of cardiac spheroids. The effectiveness of the HH‐chip was demonstrated by simultaneously forming 50 mouse embryonic stem cell‐derived embryonic bodies, which sequentially differentiated into 90% beating cardiac spheroids within 15 days of culture on the chip. A comparison of our HH‐chip method with traditional hanging‐drop and low‐attachment plate methods revealed that the HH‐chip could generate higher contracting proportions of cardiac spheroids with higher expression of cardiac markers. Additionally, we verified that the contraction frequencies of the cardiac spheroids generated from the HH‐chip were sensitive to cardiotoxic drugs. Overall, our results suggest that the microfluidic hanging drop chip‐based approach is a high‐throughput and highly efficient method for generating contracting mouse embryonic stem cell‐derived cardiac spheroids for cardiac toxicity and drug testing applications.

TMEM100 acts as a TAK1 receptor that prevents pathological cardiac hypertrophy progression

Pathological cardiac hypertrophy is the primary cause of heart failure, yet its underlying mechanisms remain incompletely understood. Transmembrane protein 100 (TMEM100) plays a role in various disorders, such as nervous system disease, pain and tumorigenesis, but its function in pathological cardiac hypertrophy is still unknown. In this study, we observed that TMEM100 is upregulated in cardiac hypertrophy. Functional investigations have shown that adeno-associated virus 9 (AAV9) mediated-TMEM100 overexpression mice attenuates transverse aortic constriction (TAC)-induced cardiac hypertrophy, including cardiomyocyte enlargement, cardiac fibrosis, and impaired heart structure and function. We subsequently demonstrated that adenoviral TMEM100 (AdTMEM100) mitigates phenylephrine (PE)-induced cardiomyocyte hypertrophy and downregulates the expression of cardiac hypertrophic markers in vitro, whereas TMEM100 knockdown exacerbates cardiomyocyte hypertrophy. The RNA sequences of the AdTMEM100 group and control group revealed that TMEM100 was involved in oxidative stress and the MAPK signaling pathway after PE stimulation. Mechanistically, we revealed that the transmembrane domain of TMEM100 (amino acids 53–75 and 85–107) directly interacts with the C-terminal region of TAK1 (amino acids 1–300) and inhibits the phosphorylation of TAK1 and its downstream molecules JNK and p38. TAK1-binding-defective TMEM100 failed to inhibit the activation of the TAK1-JNK/p38 pathway. Finally, the application of a TAK1 inhibitor (iTAK1) revealed that TAK1 is necessary for TMEM100-mediated cardiac hypertrophy. In summary, TMEM100 protects against pathological cardiac hypertrophy through the TAK1-JNK/p38 pathway and may serve as a promising target for the treatment of cardiac hypertrophy.

Low Thyroid Hormones Level Attenuates Mitochondrial Dysfunction and Right Ventricular Failure in Pulmonary Hypertensive Rats.

This study is to investigate the repercussions of hypothyroidism in the pathophysiological progression of pulmonary arterial hypertension (PAH). While the control (CTL, n = 5) male Wistar rats received vehicle, PAH was induced with monocrotaline (MCT group, n = 15). Hypothyroidism was induced in a subset of rats by methimazole 3weeks prior to the MCT injection (MMZ + MCT group, n = 15). Plasma thyroid hormones were measured by radioimmunoassay. Electrocardiographic, echocardiographic, and hemodynamic analyses were performed to evaluate the progression of PAH. Gene expression of antioxidant enzymes and cardiac hypertrophy markers were assessed by qPCR. Mitochondrial respiration, ATP levels, and ROS production were measured in right ventricular (RV) samples. Plasma T3 and T4 decreased in both MCT and MMZ + MCT groups (p < 0.05). Right ventricular systolic pressure (RVSP) increased, and RV - dP/dt, + dP/dt, and contractility index decreased in the MCT versus the CTL group and remained within control levels in the MMZ + MCT group (p < 0.05). Relative RV weight, RV wall thickness, RV diastolic area, and relative lung weight were augmented in the MCT versus the CTL group, whereas all parameters were improved to the CTL levels in the MMZ + MCT group (p < 0.05). Only the MCT group exhibited an increased duration of QTc interval compared to the baseline period (p < 0.05). ADP-induced mitochondrial respiration and ATP levels were decreased, and ROS production was increased in MCT versus the CTL group (p < 0.05), while the MMZ + MCT group exhibited increased mitochondrial respiration versus the MCT group (p < 0.05). Hypothyroidism attenuated the RV mitochondrial dysfunction and the pathophysiological progression of MCT-induced PAH.

Optimizing Cardiomyocyte Differentiation: Comparative Analysis of Bone Marrow and Adipose-Derived Mesenchymal Stem Cells in Rats Using 5-Azacytidine and Low-Dose FGF and IGF Treatment.

Mesenchymal stem cells (MSCs) exhibit multipotency, self-renewal, and immune-modulatory properties, making them promising in regenerative medicine, particularly in cardiovascular treatments. However, optimizing the MSC source and induction method of cardiac differentiation is challenging. This study compares the cardiomyogenic potential of bone marrow (BM)-MSCs and adipose-derived (AD)-MSCs using 5-Azacytidine (5-Aza) alone or combined with low doses of Fibroblast Growth Factor (FGF) and Insulin-like Growth Factor (IGF). BM-MSCs and AD-MSCs were differentiated using two protocols: 10 μmol 5-Aza alone and 10 μmol 5-Aza with 1 ng/mL FGF and 10 ng/mL IGF. Morphological, transcriptional, and translational analyses, along with cell viability assessments, were performed. Both the MSC types exhibited similar morphological changes; however, AD-MSCs achieved 70-80% confluence faster than BM-MSCs. Surface marker profiling confirmed CD29 and CD90 positivity and CD45 negativity. The differentiation protocols led to cell flattening and myotube formation, with earlier differentiation in AD-MSCs. The combined protocol reduced cell mortality in BM-MSCs and enhanced the expression of cardiac markers (MEF2c, Troponin I, GSK-3β), particularly in BM-MSCs. Immunofluorescence confirmed cardiac-specific protein expression in all the treated groups. Both MSC types exhibited the expression of cardiac-specific markers indicative of cardiomyogenic differentiation, with the combined treatment showing superior efficiency for BM-MSCs.

The interplay between doxorubicin chemotherapy, antioxidant system, and cardiotoxicity: Unrevealing of the protective potential of tannic acid.

Cardiotoxicity is the leading side effect of anthracycline-based chemotherapy. Therefore, it has gained importance to reveal chemotherapy-supporting strategies and reliable agents with their mechanisms of action. Tannic acid (TA), a naturally occurring plant polyphenol, has diverse physiological effects, including anti-inflammatory, anticarcinogenic, antioxidant, and radical scavenging properties. Therefore, this study was designed to investigate whether TA exerts a protective effect on mechanisms contributing to anthracycline-induced cardiotoxicity in rat heart tissues exposed to doxorubicin (DOX). Rats were randomly divided into control and experimental groups and treated with (18mg/kg) DOX, TA (50mg/kg), and DOX+TA during the 2 weeks. Cardiac gene markers and mitochondrial DNA (mtDNA) content were evaluated in the heart tissues of all animals. In addition to major metabolites, mRNA expression changes and biological activity responses of components of antioxidant metabolism were examined in the heart tissues of all animals. The expression of cardiac gene markers increased by DOX exposure was significantly reduced by TA treatment, whereas mtDNA content, which was decreased by DOX exposure, was significantly increased. TA also improved antioxidant metabolism members' gene expression and enzymatic activity, including glutathione peroxidase, glutathione s-transferase, superoxide dismutase, catalase, and thioredoxin reductase. This study provides a detailed overview of the current understanding of DOX-induced cardiotoxicity and preventive or curative measures involving TA.

Abstract We041: In vitro characterization of different human-induced pluripotent stem cell-derived cardiac progenitors

Introduction: Myocardial Infarction (MI) is the number one cause of death in the United States. The heart undergoes severe trauma during MI, which results in the death of cardiac cells. Although the cardiac tissue cannot regenerate on its own, regenerative medicine approaches involving cell transplantation have been shown to improve the cardiac function. Among different cell types, human induced pluripotent stem cell-derived cardiac progenitor cells (hiPSCs) have been shown to have the ability to proliferate and differentiate into cardiac lineage cells and therefore, are a promising source for myocardial repair. Here, we characterized two distinct populations of hiPSC-CPCs and assessed their differentiation potential. Methods: We compared hiPSC-CPCs differentiated using the small molecule, isoxazole-9 (ISX-9), ISX9-hiPSC-CPCs with the commercially acquired iCell hiPSC-CPCs (Fujifilm Cellular Dynamics Int.). The expression of different cardiac lineage markers were assessed via immunostaining, qPCR and flow cytometry. Furthermore, we assessed the proliferation of the cells using immunostaining and XTT assays. We also evaluated their in vitro differentiation to cardiomyocytes, via immunostaining and qPCR analysis. Results: Our studies showed similar expression of different cardiac progentior markers (Nkx2.5, GATA4, KFL-4, ISL-1, BRY-T, MESP-1, MYH-6, CTnT) in the two hiPSC-CPC populations. However, while the iCell hiPSC-CPCs predominantly expressed the cell surface marker KDR, the ISX-9-hiPSC-CPCs predominantly expressed SSEA-1. The iCell-hiPSC-CPCs showed higher proliferation rates when compared to the ISX-9-hiPSC-CPCs. However, &gt;95% of both the cell populations expressed the proliferation marker, ki67. Finally, the while both the CPC populations could differentiate into cardiomyocytes (cTNT + ), only a few of these differentiated cardiomyocytes showed spontaneous contractility in vitro. Conclusion: In our study, we have compared and characterized two distinct populations of hiPSC-CPCs to identify a promising candidate for myocardial regeneration therapies.

Abstract Mo106: Inhibition of microRNA-200c promotes regeneration of the ischemic injured myocardium through activation of developmental pathways

Ischemic injury and adverse post-infarction myocardial remodeling are major causes of heart failure worldwide. Strategies designed to offset cell death with cardiomyocyte regeneration have, to date, not translated to routine clinical practice. Mir-200c modulates the transcripts of cardiogenic transcription factors (TFs) Tbx5 , Gata4 , Mef2c to promote myocyte maturation. We hypothesized that inhibition of mir-200c activity would result in postnatal myocyte de-differentiation and replication sufficient to ameliorate post-infarction decompensation after ischemic injury. To test this hypothesis, we preformed left coronary ligation on Wild-Type (WT) and transgenic mice expressing an RNA inhibitor against miR-200c ( PMIS-C ). Echocardiographic left ventricular (LV) ejection fraction (EF) fell from 88.41 ± 1.08% (WT) and 90% ± 1.42% ( PMIS-C ) (p=NS) to 28% ± 11.55% (WT) and 36% ± 9.35% at 1 day post injury (DPI) (p =NS). At 21DPI, LVEF was 27% ± 4.31% (WT) and 64% ± 4.25% ( PMIS-C ) [p ≤ 0.0001]. Post-infarction LV chamber dilation was reversed in PMIS-C mice (1.136 ± 0.19 v 0.67 ± 0.06 p ≤ 0.004 LV Vol/mass). By 9 WPI, PMIS-C heart function within non-significantly levels of sham and function prior to injury. These results indicated that inhibiting miR-200c following ischemic injury can recover cardiac function and prevent LV dilation. Moreover, trichrome stain showed a decrease in fibrosis 3 WPI (WT: 57% ± 17.46 v PMIS-C : 12% ± 3.01 p ≤ 0.001) and 9 WPI. To understand the mechanism causing this phenomenon, we analyzed expression of cardiac progenitor markers. Fold change in expression of TFs Tbx5, Gata4, Mef2c, and Isl1 were increased at 1 and 3 DPI in PMIS-C . At 1 WPI, PMIS-C border zone CMs express markers of a “progenitor-like” cell state seen during cardiogenesis. Conclusions: Inhibiting miR-200c abrogates post-infarction LV remodeling and significantly restores LV systolic function. Ongoing studies are investigating the therapeutic use of PMIS-C through delivery via AAV and nanoparticles.

Inhibition of cytochrome P450 epoxygenase promotes endothelium-to-mesenchymal transition and exacerbates doxorubicin-induced cardiovascular toxicity

BackgroundDoxorubicin (DOX) is a potent chemotherapy widely used in treating various neoplastic diseases. However, the clinical use of DOX is limited due to its potential toxic effect on the cardiovascular system. Thus, identifying the pathway involved in this toxicity may help minimize chemotherapy risk and improve cancer patients’ quality of life. Recent studies suggest that Endothelial-to-Mesenchymal transition (EndMT) and endothelial toxicity contribute to the pathogenesis of DOX-induced cardiovascular toxicity. However, the molecular mechanism is yet unknown. Given that arachidonic acid and associated cytochrome P450 (CYP) epoxygenase have been involved in endothelial and cardiovascular function, we aimed to examine the effect of suppressing CYP epoxygenases on DOX-induced EndMT and cardiovascular toxicity in vitro and in vivo.Methods and ResultsTo test this, human endothelial cells were treated with DOX, with or without CYP epoxygenase inhibitor, MSPPOH. We also investigated the effect of MSPPOH on the cardiovascular system in our zebrafish model of DOX-induced cardiotoxicity. Our results showed that MSPPOH exacerbated DOX-induced EndMT, inflammation, oxidative stress, and apoptosis in our endothelial cells. Furthermore, we also show that MSPPOH increased cardiac edema, lowered vascular blood flow velocity, and worsened the expression of EndMT and cardiac injury markers in our zebrafish model of DOX-induced cardiotoxicity.ConclusionOur data indicate that a selective CYP epoxygenase inhibitor, MSPPOH, induces EndMT and endothelial toxicity to contribute to DOX-induced cardiovascular toxicity.

Interleukin-5 alleviates cardiac remodelling via the STAT3 pathway in angiotensin II-infused mice.

Interleukin-5 (IL-5) has been reported to be involved in cardiovascular diseases, such as atherosclerosis and cardiac injury. This study aimed to investigate the effects of IL-5 on cardiac remodelling. Mice were infused with angiotensin II (Ang II), and the expression and source of cardiac IL-5 were analysed. The results showed that cardiac IL-5 expression was time- and dose-dependently decreased after Ang II infusion, and was mainly derived from cardiac macrophages. Additionally, IL-5-knockout (IL-5-/-) mice were used to observe the effects of IL-5 knockout on Ang II-induced cardiac remodelling. We found knockout of IL-5 significantly increased the expression of cardiac hypertrophy markers, elevated myocardial cell cross-sectional areas and worsened cardiac dysfunction in Ang II-infused mice. IL-5 deletion also promoted M2 macrophage differentiation and exacerbated cardiac fibrosis. Furthermore, the effects of IL-5 deletion on cardiac remodelling was detected after the STAT3 pathway was inhibited by S31-201. The effects of IL-5 on cardiac remodelling and M2 macrophage differentiation were reversed by S31-201. Finally, the effects of IL-5 on macrophage differentiation and macrophage-related cardiac hypertrophy and fibrosis were analysed invitro. IL-5 knockout significantly increased the Ang II-induced mRNA expression of cardiac hypertrophy markers in myocardial cells that were co-cultured with macrophages, and this effect was reversed by S31-201. Similar trends in the mRNA levels of fibrosis markers were observed when cardiac fibroblasts and macrophages were co-cultured. In conclusions, IL-5 deficiency promote the differentiation of M2 macrophages by activating the STAT3 pathway, thereby exacerbating cardiac remodelling in Ang II-infused mice. IL-5 may be a potential target for the clinical prevention of cardiac remodelling.

Global ischemia induces stemness and dedifferentiation in human adult cardiomyocytes after cardiac arrest

Global ischemia has been shown to induce cardiac regenerative response in animal models. One of the suggested mechanisms behind cardiac regeneration is dedifferentiation of cardiomyocytes. How human adult cardiomyocytes respond to global ischemia is not fully known. In this study, biopsies from the left ventricle (LV) and the atrioventricular junction (AVj), a potential stem cell niche, were collected from multi-organ donors with cardiac arrest (N = 15) or without cardiac arrest (N = 6). Using immunohistochemistry, we investigated the expression of biomarkers associated with stem cells during cardiomyogenesis; MDR1, SSEA4, NKX2.5, and WT1, proliferation markers PCNA and Ki67, and hypoxia responsive factor HIF1α. The myocyte nuclei marker PCM1 and cardiac Troponin T were also included. We found expression of cardiac stem cell markers in a subpopulation of LV cardiomyocytes in the cardiac arrest group. The same cells showed a low expression of Troponin T indicating remodeling of cardiomyocytes. No such expression was found in cardiomyocytes from the control group. Stem cell biomarker expression in AVj was more pronounced in the cardiac arrest group. Furthermore, co-expression of PCNA and Ki67 with PCM1 was only found in the cardiac arrest group in the AVj. Our results indicate that a subpopulation of human cardiomyocytes in the LV undergo partial dedifferentiation upon global ischemia and may be involved in the cardiac regenerative response together with immature cardiomyocytes in the AVj.

The impact of high nicotine concentrations on the viability and cardiac differentiation of mesenchymal stromal cells: a barrier to regenerative therapy for smokers.

Background: Current treatment methods are not successful in restoring the lost cardiomyocytes after injury. Stem cell-based strategies have attracted much attention in this regard. Smoking, as a strong cardiovascular risk factor, not only affects the cardiac cells adversely but also deteriorates the function of stem cells. Since mesenchymal stem cells (MSCs) are one of the popular candidates in cardiovascular disease (CVD) clinical trials, we investigated the impact of nicotine on the regenerative properties (viability and cardiac differentiation) of these cells. Methods: MSCs were isolated from rat bone marrow and characterized based on morphology, differentiation capability, and the expression of specific mesenchymal markers. The MTT assay was used to assess the viability of MSCs after being exposed to different concentrations of nicotine. Based on MTT findings and according to the concentration of nicotine in smokers' blood, the growth curve and population doubling time were investigated for eight consecutive days. Cells were treated with 5-azacytidine (an inducer of cardiac differentiation), and then the expressions of cardiac-specific markers were calculated by qPCR. Results: MSCs were spindle-shaped, capable of differentiating into adipocyte and osteocyte, and expressed CD73 and CD90. The viability of MSCs was reduced upon exposure to nicotine in a concentration- and time-dependent manner. The growth curve showed that nicotine reduced the proliferation of MSCs, and treated cells needed more time to double. In addition, the expressions of GATA4 and troponin were downregulated in nicotine-treated cells on day 3. However, these two cardiac markers were overexpressed on day 7. Conclusion: Nicotine decreased normal growth and reduced the expression of cardiac markers in MSCs. This aspect is of eminent importance to smokers with cardiovascular disease who are candidates for stem cell therapy.

Protective activities of silver nanoparticles containing Panax japonicus on apoptotic, inflammatory, and oxidative alterations in isoproterenol-induced cardiotoxicity

Abstract Panax japonicus has long been utilized as an herbal remedy in Chinese traditional medicine for treating various diseases. In this investigation, we present the environmentally friendly silver nanoparticle (AgNP) synthesis by the aqueous extract of P. japonicas to follow its cardioprotective effects. Through various analytical methods, we identified the nanoparticles (NPs). Our XRD findings revealed the formation of Ag@P. japonicus, while FE-SEM imagery indicated a spherical shape, with NPs measuring less than 40 nm. The UV–Vis and FT-IR spectroscopy confirm the green synthesis of Ag@P. japonicus. In the medicinal section, 45 Wistar rats were utilized. These groups consisted of a normal group, a group that was solely treated with isoproterenol for inducing myocardial infarction, and two groups that were pretreated with AgNPs at different doses for 14 days. These pretreated groups were then challenged with isoproterenol. The expression of PI3K/Akt/mTOR and other downstream inflammatory and apoptotic mediators were followed. Additionally, the expression of Keap1, Nrf2, ECG, cardiac markers, and other downstream antioxidant enzymes were assessed. Treatment with AgNPs ameliorated the apoptosis, inflammation, and myocardial autophagy, regulated the PI3K/Akt/mTOR pathway, increased the antioxidant enzyme efficacies, and activated the Keap1/Nrf2/HO-1 pathway. The findings suggest that AgNPs may have a cardioprotective efficacy on myocardial infarction by mitigating the Keap1/Nrf2 pathway, GST, GPx, GSH, SOD, IL-1β, IL-6, TNF-α, NF-κB, Bax, Bcl2, caspase-9, caspase-3, and PI3K/Akt/mTOR pathway. Furthermore, the treatment decreased the infarct region size, attenuated the cardiac indicators levels, and mitigated immune cell infiltration and myocardial necrosis.

Thioredoxin 2 protects mice against experimental myocardial infarction

Graphical abstract Experimental Myocardial infarction (MI) using ligation procedure induces cardiac dysfunction, high level of ROS, inflammation, apoptosis, fibrosis and cardiomyocyte (CM) loss. AAV overexpressing human Trx-2, specifically in CM mitochondria improves mouse cardiac function, reduces the size of cardiac infarct, increases the expression of cardiac anti-inflammatory markers, reduces apoptosis and oxidative stress. However, it does not increase CM proliferation. Abstract Introduction and objective Myocardial infarction (MI), which in general results from complications of atherosclerosis, is characterized by high inflammation and cardiomyocytes (CMs) apoptosis and by major loss of CMs. Regeneration of these lost CMs represents a major challenge for MI therapy. The increase of mitochondrial reactive oxygen species (ROS) is involved in cell cycle arrest which can be restarted by hypoxia or in the presence of ROS scavengers. Among ROS scavengers, mitochondrial thioredoxin 2 (Trx-2), an important antioxidant protein, could play a role in the CMs renewal. Method In this study, we investigated the effect of Trx-2 on mouse heart after an experimental MI. Results Trx-2 improves mouse cardiac function, reduces cardiac infarction size and increases the expression of cardiac anti-inflammatory markers. In addition, it reduces apoptosis and oxidative stress in heart tissue of mice after MI but it does not increase CM proliferation in cell culture or in heart tissue. Conclusion Mitochondrial Trx-2 effectively protects against heart infarction, likely via the reduction of oxidative stress, inflammation and apoptosis but not through CM renewal. Significance statement The current study unveils the complexities of MI and highlights mitochondrial Trx-2 role. Post-MI, marked by inflammation, CM apoptosis and significant CM loss. Trx-2 emerges as a vital protector. Its intervention improves mouse cardiac function, reduces infarction size and fosters an anti-inflammatory environment. By uncovering these mechanisms, the study suggests potential therapeutic strategies for oxidative stress, inflammation and apoptosis in MI, positioning Trx-2 as a promising candidate for future cardiac interventions.

Vascularised cardiac spheroids-on-a-chip for testing the toxicity of therapeutics

Microfabricated organ-on-a-chips are rapidly becoming the gold standard for the testing of safety and efficacy of therapeutics. A broad range of designs has emerged, but recreating microvascularised tissue models remains difficult in many cases. This is particularly relevant to mimic the systemic delivery of therapeutics, to capture the complex multi-step processes associated with trans-endothelial transport or diffusion, uptake by targeted tissues and associated metabolic response. In this report, we describe the formation of microvascularised cardiac spheroids embedded in microfluidic chips. Different protocols used for embedding spheroids within vascularised multi-compartment microfluidic chips were investigated first to identify the importance of the spheroid processing, and co-culture with pericytes on the integration of the spheroid within the microvascular networks formed. The architecture of the resulting models, the expression of cardiac and endothelial markers and the perfusion of the system was then investigated. This confirmed the excellent stability of the vascular networks formed, as well as the persistent expression of cardiomyocyte markers such as cTNT and the assembly of striated F-actin, myosin and α-actinin cytoskeletal networks typically associated with contractility and beating. The ability to retain beating over prolonged periods of time was quantified, over 25 days, demonstrating not only perfusability but also functional performance of the tissue model. Finally, as a proof-of-concept of therapeutic testing, the toxicity of one therapeutic associated with cardiac disfunction was evaluated, identifying differences between direct in vitro testing on suspended spheroids and vascularised models.

Unveiling the Antiviral Properties of Panduratin A through SARS-CoV-2 Infection Modeling in Cardiomyocytes.

Establishing a drug-screening platform is critical for the discovery of potential antiviral agents against SARS-CoV-2. In this study, we developed a platform based on human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) to investigate SARS-CoV-2 infectivity, with the aim of evaluating potential antiviral agents for anti-SARS-CoV-2 activity and cardiotoxicity. Cultured myocytes of iPSC-CMs and immortalized human cardiomyocyte cell line (AC-16) were primarily characterized for the expression of cardiac markers and host receptors of SARS-CoV-2. An infectivity model for the wild-type SARS-CoV-2 strain was then established. Infection modeling involved inoculating cells with SARS-CoV-2 at varying multiplicities of infection (MOIs) and then quantifying infection using immunofluorescence and plaque assays. Only iPSC-CMs, not AC16 cells, expressed angiotensin-converting enzyme 2 (ACE-2), and quantitative assays confirmed the dose-dependent infection of iPSC-CMs by SARS-CoV-2, unlike the uninfectable AC16 cells lacking the expression of ACE2. Cytotoxicity was evaluated using MTT assays across a concentration range. An assessment of the plant-derived compound panduratin A (panA) showed cytotoxicity at higher doses (50% cytotoxic concentration (CC50) 10.09 μM) but promising antiviral activity against SARS-CoV-2 (50% inhibition concentration (IC50) 0.8-1.6 μM), suppressing infection at concentrations 10 times lower than its CC50. Plaque assays also showed decreased viral production following panA treatment. Overall, by modeling cardiac-specific infectivity, this iPSC-cardiomyocyte platform enables the reliable quantitative screening of compound cytotoxicity alongside antiviral efficacy. By combining disease pathogenesis and pharmacology, this system can facilitate the evaluation of potential novel therapeutics, such as panA, for drug discovery applications.

C-C Motif Chemokine 2 Regulates Macrophage Polarization and Contributes to Myocardial Infarction Healing.

Macrophages are crucial immune cells that play essential roles in the healing of myocardial infarction (MI), undergoing continuous polarization throughout this process. C-C motif chemokine 2 (CCL2) is a chemokine that regulates inflammatory responses during MI. However, the extent to which CCL2 influences macrophage polarization and MI healing remains incompletely understood. In this study, we investigate the role of CCL2 in macrophage polarization and MI healing. Our findings reveal that CCL2 is differentially expressed in lipopolysaccharide (LPS)-induced M1 and interleukin (IL)-4-induced M2 RAW264.7 macrophages. Knockdown of CCL2 attenuates TNF-α secretion stimulated by LPS, while overexpression of CCL2 mitigates IL-10 production triggered by IL-4 in these macrophages. Moreover, CCL2 deficiency disrupts LPS-induced M1 polarization, whereas CCL2 overexpression reduces M2 polarization of RAW264.7 macrophages induced by IL-4. Further exploration indicates that the promotion of M1 polarization by CCL2 is significantly impaired by inhibition of the p38-mediated MAPK pathway and NF-κB pathway. In a MI mouse model, CCL2 knockdown remarkably reduces infarct size, collagen synthesis, and the expression of cardiac fibrosis and hypertrophy markers. The activity of the p38-mediated MAPK pathway and NF-κB pathway is downregulated by CCL2 knockdown as well. Additionally, the number of total macrophages and M1 macrophages in the infarct decreases, while the number of M2 macrophages increases upon CCL2 deficiency. In conclusion, these results suggest that CCL2 is a key regulator of macrophage polarization, controlling MI healing in vivo.

Thioredoxin-1 and its mimetic peptide improve systolic cardiac function and remodeling after myocardial infarction.

Myocardial infarction (MI) is characterized by a significant loss of cardiomyocytes (CMs), and it is suggested that reactive oxygen species (ROS) are involved in cell cycle arrest, leading to impaired CM renewal. Thioredoxin-1 (Trx-1) scavenges ROS and may play a role in restoring CM renewal. However, the truncated form of Trx-1, Trx-80, can compromise its efficacy by exerting antagonistic effects. Therefore, a Trx-1 mimetic peptide called CB3 was tested as an alternative way to restore CMs. This study aimed to investigate the effects of Trx-1, Trx-80, and CB3 on mice with experimental MI and study the underlying mechanism of CB3 on CMs. Mouse cardiac parameters were quantified by echocardiography, and infarction size and fibrosis determined using Trichrome and Picro-Sirius Red staining. The study found that Trx-1 and CB3 improved mouse cardiac function, reduced the size of cardiac infarct and fibrosis, and decreased the expression of cardiac inflammatory markers. Furthermore, CB3 polarized macrophages into M2 phenotype, reduced apoptosis and oxidative stress after MI, and increased CM proliferation in cell culture and invivo. CB3 effectively protected against myocardial infarction and could represent a new class of compounds for treating MI.

Phenylacetyl glutamine (PAGln) enhances cardiomyocyte death after myocardial infarction through β1 adrenergic receptor.

This study aims to explore the roles of phenylacetyl glutamine (PAGln) on myocardial infarction (MI) pathogenesis. Here, using targeted metabolomics analysis, it was found that the plasma metabolite PAGln was upregulated in coronary artery disease (CAD) patients and MI mice and could be an independent risk factor for CAD. In vivo and in vitro functional experiments revealed that PAGln pretreatment enhanced MI-induced myocardial injury and cardiac fibrosis, as evident by the increased infarct size, cardiomyocyte death, and the upregulated expression of cardiac fibrosis markers (Col1a1 and α-SMA). Combined with RNA-sequencing analysis and G protein-coupled receptor (GPCR) inhibitor, we found that the GPCR signaling activation is essential for PAGln-mediated effects on cardiomyocyte death. Furthermore, drug affinity responsive target stability and cellular thermal shift assay demonstrated that PAGln could interact with β1-adrenergic receptor (AR). Moreover, β1-AR blocker treatment indeed extended the cardiac remodeling after PAGln-enhanced MI. These results suggest that PAGln might be a potential therapeutic target for extending the cardiac remodeling window in MI patients that signals via β1-AR.

Ameliorating impaired cardiac function in myocardial infarction using exosome-loaded gallic-acid-containing polyurethane scaffolds

Myocardial infarction (MI) can be tackled by implanting cardiac patches which provide mechanical support to the heart. However, most tissue-engineered scaffolds face difficulty in attenuating oxidative stress, maintaining mechanical stability, and regenerating damaged cardiomyocytes. Here, we fabricated elastic cryogels using polyurethane modified with antioxidant gallic acid in its backbone (PUGA) and further coated them with decellularized extracellular matrix (dECM) to improve adhesiveness, biocompatibility and hemocompatibility. The scaffold was functionalized with exosomes (EXO) isolated from adipose-derived stem cells having regenerative potential. PUGA-dECM + EXO was tested in a rat model with induced MI where echocardiography after 8 weeks of implantation showed significant recovery in treatment group. Histological analysis revealed a decrease in fibrosis after application of patch and promotion of angiogenesis with reduced oxidative stress was shown by immunostaining. Expression of cardiac tissue contractile function marker was also observed in treatment groups. Thus, the proposed biomaterial has a promising application to be utilized as a patch for cardiac regeneration. More detailed studies with larger animal species are needed for using these observations for specific applications.

Therapeutic potential of kaempferide against paraquat instigated cardiac toxicity in rats

Paraquat (PQ) is an effective herbicide however, due to its adverse effects on different organs including heart, it is considered as highly toxic to human beings. Kaempferide (KMF) is a plant-based flavonoid with conspicuous pharmacological properties. This experiment was executed to evaluate the palliative actions of KMF on PQ prompted cardiac toxicity in rats. Twenty-four rats were apportioned into 4 equal groups which were designated as control, toxicant (PQ treated), Co-treated (PQ + KMF) and KMF group. After 30 days of treatment, PQ intoxication resulted in a remarkable reduction in antioxidant enzymes activities which include, glutathione reductase (GSH), glutathione S-transferase (GST), catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD), and glutathione disulfide reductase (GSR), whereas an elevation was observed in reactive oxygen species (ROS), & malondialdehyde (MDA) as well as hydrogen peroxide (H2O2) level. Furthermore, concentrations of cardiac injury markers, creatinine phosphokinase (CPK), creatine kinase-myoglobin binding (CK-MB), & lactate dehydrogenase (LDH), as well as troponin I were increased in response to PQ treatment. Moreover, inflammatory cytokines such as tumour necrosis factor alpha (TNF-α), nuclear factor-kappa B (NF-κB), and interleukin-6 (IL-6), interleukin-1 beta (lL-1β), and cyclooxygenase-2 (COX-2) levels were augmented in PQ intoxicated group. PQ exposure reduced the gene expression of cardiac anti-apoptotic markers (Bcl-2), but the gene expression of apoptotic marker (caspase-9, caspase-3 and Bax) was increased. Histopathological damages were also observed in toxicant (PQ) exposed group. However, the administration of KMF significantly palliated PQ induced aforementioned disruptions. In the light of these findings, it is concluded that KMF is a promising bioactive compound that may be used as a curative agent against PQ instigated cardiac damage due to its marvelous antioxidant, anti-apoptotic, anti-inflammatory as well as cardioprotective potential.