Cardiomyocyte Toxicity Research Articles

Cardioprotective Effect of Maternal Supplementation with Resveratrol on Toxicity Induced by Doxorubicin in Offspring Cardiomyocytes.

ResumoFundamentoA doxorrubicina (DOX) é frequentemente usada para tratar muitos tipos de cânceres, apesar da cardiotoxicidade dose-dependente. Como alternativa, o resveratrol é um polifenol que tem demonstrado efeitos cardioprotetores em vários modelos de disfunção cardíaca.ObjetivoEste estudo investigou se o tratamento com resveratrol em ratas gestantes protege contra toxicidade induzida por doxorrubicina em cardiomiócitos da ninhada.MétodosRatas Wistar (n-8) receberam sresveratrol como suplemento alimentar durante a gestação. No nascimento da ninhada, os corações (9-11) foram usados para se obter a cultura primária de cardiomiócitos. A cardiotoxicidade induzida por DOX e os efeitos da suplementação com resveratrol foram avaliados por marcadores de stress oxidativo, tais como oxidação da diclorofluoresceína diacetato, diminuição da atividade de enzimas antioxidantes, e oxidação do teor total de grupos sulfidrila, além da avaliação da viabilidade celular, geração de danos ao DNA, bem como a resposta de reparo aos danos ao DNA. Um valor de p <0,05 foi considerado estatisticamente significativo.ResultadosOs cardiomiócitos de neonatos de ratas que receberam suplemento resveratrol apresentaram um aumento (p <0,01) na viabilidade das células, e diminuição (p <0,0001) de células apoptóticas/necróticas após o tratamento com DOX, o que está correlacionado às atividades de enzimas antioxidantes e produção de diclorofluoresceína. Além disso, o resveratrol protegeu os cardiomiócitos de danos ao DNA induzidos por DOX, apresentando uma diminuição (p <0,05) nas quebras de DNA induzidas por stress oxidativo, avaliadas pela atividade de enzimas reparadoras do DNA endonuclease III e formamidopirimidina glicosilase. A suplementação com resveratrol aumentou (p <0,05) a expressão da proteína reparadora Sirt6 nos cardiomiócitos dos filhotes.ConclusãoEssa pesquisa indica que a suplementação com resveratrol durante o período gestacional tem um efeito cardioprotetor no coração da ninhada contra a toxicidade induzida por DOX, o que pode se dever a sua função antioxidante, e o aumento na resposta de danos ao DNA.

Molecular mechanisms of anthracycline cardiovascular toxicity.

Anthracyclines are effective chemotherapeutic agents, commonly used in the treatment of a variety of hematologic malignancies and solid tumors. However, their use is associated with a significant risk of cardiovascular toxicities and may result in cardiomyopathy and heart failure. Cardiomyocyte toxicity occurs via multiple molecular mechanisms, including topoisomerase II-mediated DNA double-strand breaks and reactive oxygen species (ROS) formation via effects on the mitochondrial electron transport chain, NADPH oxidases (NOXs), and nitric oxide synthases (NOSs). Excess ROS may cause mitochondrial dysfunction, endoplasmic reticulum stress, calcium release, and DNA damage, which may result in cardiomyocyte dysfunction or cell death. These pathophysiologic mechanisms cause tissue-level manifestations, including characteristic histopathologic changes (myocyte vacuolization, myofibrillar loss, and cell death), atrophy and fibrosis, and organ-level manifestations including cardiac contractile dysfunction and vascular dysfunction. In addition, these mechanisms are relevant to current and emerging strategies to diagnose, prevent, and treat anthracycline-induced cardiomyopathy. This review details the established and emerging data regarding the molecular mechanisms of anthracycline-induced cardiovascular toxicity.

Next generation risk assessment (NGRA): Bridging in vitro points-of-departure to human safety assessment using physiologically-based kinetic (PBK) modelling – A case study of doxorubicin with dose metrics considerations

Using the chemical doxorubicin (DOX), the objective of the present study was to evaluate the impact of dose metrics selection in the new approach method of integrating physiologically-based kinetic (PBK) modelling and relevant human cell-based assays to inform a priori the point of departure for human health risk. We reviewed the literature on the clinical consequences of DOX treatment to identify dosing scenarios with no or mild cardiotoxicity observed. Key concentrations of DOX that induced cardiomyocyte toxicity in vitro were derived from studies of our own and others. A human population-based PBK model of DOX was developed and verified against pharmacokinetic data. The model was then used to predict plasma and extracellular and intracellular heart concentrations of DOX under selected clinical settings and compared with in vitro outcomes, based on several dose metrics: Cmax (maximum concentration) or AUC (area under concentration-time curve) in free or total form of DOX. We found when using in vitro assays to predict cardiotoxicity for DOX, AUC is a better indicator. Our study illustrates that when appropriate dose metrics are used, it is possible to combine PBK modelling with in vitro-derived toxicity information to define margins of safety and predict low-risk human exposure levels.

Gastrodin protects against high glucose-induced cardiomyocyte toxicity via GSK-3β-mediated nuclear translocation of Nrf2.

Diabetic cardiomyopathy (DCM) is one of the major complications of diabetes that causes mortality and morbidity in diabetic patients. Gastrodin (GSTD) is a bioactive phenolic glucoside component of an ancient Chinese herb Tianma (Gastrodia elata Bl.), which is widely used for cardiovascular and cerebrovascular diseases by ancient Chinese. Up to now, whether GSTD has a beneficial effect on DCM is unclear. Therefore, this study aimed to investigate the effect of GSTD on high glucose-induced injury in H9c2 rat cardiomyocytes and HL-1 mouse cardiomyocytes, and its underlying mechanisms. High glucose (33 mM) treatment caused cardiomyocyte toxicity, oxidative stress and apoptosis in both H9c2 and HL-1 cells. Under both normal (5.5 mM glucose) and high glucose conditions, GSTD showed protective effect against high glucose-induced cytotoxicity and promoted the nuclear translocation of Nrf2 in a concentration and time-dependent manner in H9c2 and HL-1 cells. Knockdown of Nrf2 expression using siRNA specifically targeting Nrf2 attenuated the protective effect of GSTD. Furthermore, GSTD promoted the nuclear translocation of Nrf2 via activating glycogen synthase kinse-3β (GSK-3β) signaling pathway. 4-benzyl, 2-methyl, 1, 2, 4-thiadiazolidine, 3, 5 dione (TDZD-8), an inhibitor of GSK-3β, inhibited the nuclear translocation of Nrf2 induced by GSTD, and attenuated the protective effect of GSTD as Nrf2 knockdown did. In summary, GSTD could protect against high glucose-induced cardiomyocyte toxicity via GSK-3β-mediated nuclear translocation of Nrf2.

Mitochondrial Fission and Mitophagy Coordinately Restrict High Glucose Toxicity in Cardiomyocytes.

Hyperglycemia-induced mitochondrial dysfunction plays a key role in the pathogenesis of diabetic cardiomyopathy. Injured mitochondrial segments are separated by mitochondrial fission and eliminated by autophagic sequestration and subsequent degradation in the lysosome, a process termed mitophagy. However, it remains poorly understood how high glucose affects the activities of, and the relationship between, mitochondrial fission and mitophagy in cardiomyocytes. In this study, we determined the functional roles of mitochondrial fission and mitophagy in hyperglycemia-induced cardiomyocyte injury. High glucose (30 mM, HG) reduced mitochondrial connectivity and particle size and increased mitochondrial number in neonatal rat ventricular cardiomyocytes, suggesting an enhanced mitochondrial fragmentation. SiRNA knockdown of the pro-fission factor dynamin-related protein 1 (DRP1) restored mitochondrial size but did not affect HG toxicity, and Mdivi-1, a DRP1 inhibitor, even increased HG-induced cardiomyocyte injury, as shown by superoxide production, mitochondrial membrane potential and cell death. However, DRP1 overexpression triggered mitochondrial fragmentation and mitigated HG-induced cardiomyocyte injury, suggesting that the increased mitochondrial fission is beneficial, rather than detrimental, to cardiomyocytes cultured under HG conditions. This is in contrast to the prevailing hypothesis that mitochondrial fragmentation mediates or contributes to HG cardiotoxicity. Meanwhile, HG reduced mitophagy flux as determined by the difference in the levels of mitochondria-associated LC3-II or the numbers of mitophagy foci indicated by the novel dual fluorescent reporter mt-Rosella in the absence and presence of the lysosomal inhibitors. The ability of HG to induce mitochondrial fragmentation and inhibit mitophagy was reproduced in adult mouse cardiomyocytes. Overexpression of Parkin, a positive regulator of mitophagy, or treatment with CCCP, a mitochondrial uncoupler, induced mitophagy and attenuated HG-induced cardiomyocyte death, while Parkin knockdown had opposite effects, suggesting an essential role of mitophagy in cardiomyocyte survival under HG conditions. Strikingly, Parkin overexpression increased mitochondrial fragmentation, while DRP1 overexpression accelerated mitophagy flux, demonstrating a reciprocal activation loop that controls mitochondrial fission and mitophagy. Thus, strategies that promote the mutual positive interaction between mitochondrial fission and mitophagy while simultaneously maintain their levels within the physiological range would be expected to improve mitochondrial health, alleviating hyperglycemic cardiotoxicity.

Stabilization of Mitochondrial Function by Ellagic Acid Prevents Celecoxib-induced Toxicity in Rat Cardiomyocytes and Isolated Mitochondria.

The possible action of polyphenolic compounds in the reduction of reactive oxygen species (ROS) and mitochondrial toxicity may suggest them as putative agents for the treatment of drug-induced mitochondrial dysfunction and cardiotoxicity. This study was designed to explore protective effect of ellagic acid (EA) against celecoxib-induced cellular and mitochondrial toxicity in cardiomyocytes and their isolated mitochondria. In order to do this, isolated cardiomyocytes and mitochondria were pretreated with 3 different concentrations of EA (10, 50 and 100 µM), after which celecoxib (16 µg/ml) was added to promote deleterious effects on cells and mitochondria. Using flow cytometry and biochemical methods, the parameters of cellular and mitochondrial toxicity were investigated. Our results showed that celecoxib (16 µg/ml) caused a significant decrease in cell viability, mitochondrial membrane potential (MMP), glutathione (GSH) in intact cardiomyocytes and succinate dehydrogenase (SDH) activity, MMP collapse, and mitochondrial swelling, and a significant increase in reactive oxygen species (ROS) formation, lipid peroxidation (LP) and oxidative stress in isolated mitochondria. Also, our results revealed that co-administration of EA (50 and 100 µM) with celecoxib significantly attenuated the cellular and mitochondrial toxicity effects. In this study, we showed that simultaneous treatment with of EA ameliorated the cellular and mitochondrial toxicity induced by celecoxib, with cardiomyocytes presenting normal activity compared to the control group, and mitochondria retaining their normal activity.

Studies towards Non‐toxic, Water Soluble, Vasoactive Norbornene Organic Carbon Monoxide Releasing Molecules

AbstractThe optimisation of the aqueous solubility of organic carbon monoxide releasing molecules based on a norborn‐2‐en‐7‐one scaffold is reported. This culminated in the synthesis of oCOm‐54 and oCOm‐56 which contain water solubilising polyethylene oxide groups. Both compounds are highly water soluble and release CO at pH 7.4 with half‐lives of 180 and 320 minutes respectively, to produce a reversible vasodilatory response in isolated, preconstricted tissue. Preliminary analysis indicates these oCOms are capable of forming micellar particles. Both oCOms exhibit significantly less cellular toxicity in AC16 human cardiomyocytes than earlier amine‐containing oCOms.

All-Trans-Retinoic Acid Prevents Carfilzomib-Induced Cardiotoxicity By Decreasing Activation of the Renin-Angiotensin System

INTRODUCTION Bortezomib (BTZ), Carfilzomib (CFZ) and Ixazomib (IXA) are proteasome inhibitors (PI) approved for Multiple Myeloma (MM) treatment. By design, they all target the rate-limiting proteasome ß5 subunit. CFZ treatment increases the survival of patients with relapsed/refractory MM compared to BTZ. However, CFZ treatment is associated with heart failure not commonly observed for BTZ. The molecular basis for CFZ-induced cardiotoxicity is poorly understood. We have shown before that CFZ co-inhibits the ß5 and ß2 proteasome subunits compared to co-inhibition of the ß5/ß1 subunits by BTZ. We hypothesized that the unique ß5/ß2 subunit inhibition pattern of CFZ likewise explains the CFZ related acute cardiotoxicity. METHODS Isolated primary murine cardiomyocytes treated with BTZ, CFZ or ß5, ß2 and ß1 subunit-selective PI were used as in vitro model. Selectivity of proteasome subunit inhibition was confirmed with activity based chemical probes. Cardiomyocyte contractility was assessed in vitro using motion vector image analysis. The accumulation of individual proteins in cardiomyocytes undergoing 1h treatment with different PI was analyzed by liquid chromatography/mass spectrometry (LC/MS). In vivo analysis of the effects of differential proteasome subunit inhibition patterns was performed by electrocardiography (ECG) monitoring and untargeted metabolomics analysis from murine heart and plasma using R v.3.5.1 (2018-07-02) and Matlab 2020a. RESULTS Co-inhibition of ß5/ß2 proteasome subunits by CFZ or by respective subunit-specific PI for 1h resulted in increased proteasome inhibition and proteotoxic stress in cardiomyocytes compared to ß5/ß1 inhibition induced by BTZ. Likewise, CFZ or the ß5/ß2 type co-inhibition of the proteasome impaired contractility of cardiomyocytes in vitro, in contrast to BTZ or to ß5/ß1-selective proteasome inhibition. LC/MS-based proteome analysis of murine primary cardiomyocytes treated with either CFZ-type or BTZ-type proteasome inhibition identified accumulation of Retinal Dehydrogenase 1 (ALDH1A1) in PI-treated cardiomyocytes, with CFZ showing a slightly stronger effect. ALDH1A1 is involved in retinoic acid metabolism. Co-treatment of cardiomyocytes with its enzymatic end-product, all-trans-Retinoic-Acid (atRA), restored contractility of cardiomyocytes undergoing CFZ treatment in vitro. Leucyl-Cistinyl Aminopeptidase (LCAP) was identified as the protein that accumulated in CFZ-versus BTZ-treated cardiomyocytes (Log2 CFZ = 1.1, Log2 BTZ = -0.49, p=0.002). LCAP is involved in the Renin-Angiotensin System (RAS) and its increase suggests selective activation of RAS with increased degradation of RAS metabolites via LCAP in cardiomyocytes undergoing CFZ treatment. Indeed, mRNA expression for angiotensin converting enzyme 2 (Ace2) and angiotensin receptor 1 (Agtr1) was increased in beating cardiomyocytes treated with CFZ. Conversely, treatment with aminopeptidase inhibitor Bestatin prevented CFZ-induced cardiomyocyte toxicity in vitro. Consistent with our model, co-treatment of cardiomyocytes with CFZ and Valsartan, an Agtr1 inhibitor, likewise prevented CFZ- induced toxicity. In vivo, 1h CFZ treatment selectively led to acute bradycardia with local activation of the RAS and accumulation of angiotensin in the heart. CFZ/atRA co-treatment decreased local angiotensin levels and prevented CFZ-induced bradycardia. There were no differences in angiotensin plasma levels in between the treated mice, suggesting that the local RAS in the heart rather than systemic effects of the RAS mediates the cardiotoxicity of CFZ. CONCLUSION Our data suggest that CFZ specifically impairs cardiac contractility in a dose-dependent manner that is caused by its unique ß5/ß2 proteasome subunit co-inhibition pattern. CFZ leads to more efficient functional proteasome inhibition in cardiomyocytes, resulting in accumulation of LCAP that subsequently activates the local RAS and induce acute cardiotoxicity. Based on our findings, CFZ-induced cardiotoxicity may be prevented or mitigated by either blocking RAS activation at the angiotensin II receptor level using selective drugs like Valsartan, or by reducing angiotensin levels with atRA. This provides a rational strategy to prevent CFZ-induced acute cardiac toxicity by modulating the activity of the local RAS with approved drugs. Disclosures No relevant conflicts of interest to declare.

Aloe-emodin relieves zidovudine-induced injury in neonatal rat ventricular myocytes by regulating the p90rsk/p-bad/bcl-2 signaling pathway

Background/AimsZidovudine (3′-azido-2′,3′-deoxythymidine; AZT) is a first-line drug for treatment of human immunodeficiency virus infection (HIV). However, its application is limited by cardiotoxicity due to cardiomyocyte injury. This study investigated whether Aloe-emodin (AE), an anthraquinone compound, protects against AZT-induced cardiomyocyte toxicity. MethodsMTT, JC-1 assays and TUNEL were examined to verify the protective effect of AE against AZT-induced cardiomyocyte injury. Western blotting was performed to explore the anti-apoptotic effect of AE using anti-apoptotic proteins p90rsk, p-bad, and bcl-2 and pro-apoptotic proteins apaf-1, cleaved-caspase-3, and cytochrome c. ResultsWe observed a protective effect of AE against cell viability decrease and TUNEL positive cells increase induced by AZT, which was counteracted by BI-D1870. Western blot analysis found that AE significantly inhibited cardiomyocyte apoptosis by activating p90rsk/p-bad/bcl-2 signaling pathway. Furthermore, BI-D1870 counteracted the anti-apoptotic effect of AE. ConclusionsTaken together, these results indicate that AE attenuated AZT-induced cardiomyocyte apoptosis by activating p90rsk.

Ameliorative effect of Dillenia indica fruits against doxorubicin-induced cardiomyocyte toxicity

Drug-induced cardiotoxicity is a significant concern in cancer patients, and therefore cardio-oncology is gaining more attention. Doxorubicin (Dox) is a potent anticancer drug used against various malignancies, with cardiotoxicity as a dose-limiting factor. Although the mechanism of Dox-mediated cardiotoxicity is not fully understood, it is thought to encompass oxidative stress during the therapy leading to cardiotoxicity in cancer patients. Several oxidative stress-induced diseases and drug-induced toxicities can be effectively ameliorated using bioactive plant constituents. Dillenia indica (DI) is one such plant belonging to the family Dilleniaceae and is used as an ethno-medicinal agent for the treatment of various oxidative stress-mediated diseases like diabetes and cancer. In this study, we have evaluated the protective effect of the hydroalcoholic extract of Dillenia indica fruits (HADI) against the Dox-induced cardiomyocyte toxicity. The HADI was further evaluated for its efficacy in a Dox-induced cardiotoxicity models. Antioxidant assays (ABTS and DPPH) revealed a strong antioxidant potential of HADI. In vitro assay results indicated that pre-treatment with HADI had shown protective activity and reduced the ROS generation in H9c2 cell line. Non-invasive methods like high-frequency ultrasonography and electrocardiography were applied to evaluate the real time cardiac parameters. It was also found that pre-treatment with HADI restored functional parameters like ejection fraction, stroke volume as well as elevation of the T wave induced by Dox. Whereas the Dox treated mice had elevated levels of cardiac functional enzymes like creatinine kinase (CK-MB) and lactate dehydrogenase indicating the severity of cardiomyocyte toxicity. The results indicated that HADI pre-treatment has significantly reduced the upregulated enzyme levels. Taken together, our findings indicated that HADI ameliorated the Dox-induced cardiomyocyte toxicity by modulating the upregulated reactive oxygen species.

Dissecting Cellular Mechanisms of Long-Chain Acylcarnitines-Driven Cardiotoxicity: Disturbance of Calcium Homeostasis, Activation of Ca2+-Dependent Phospholipases, and Mitochondrial Energetics Collapse.

Long-chain acylcarnitines (LCAC) are implicated in ischemia-reperfusion (I/R)-induced myocardial injury and mitochondrial dysfunction. Yet, molecular mechanisms underlying involvement of LCAC in cardiac injury are not sufficiently studied. It is known that in cardiomyocytes, palmitoylcarnitine (PC) can induce cytosolic Ca2+ accumulation, implicating L-type calcium channels, Na+/Ca2+ exchanger, and Ca2+-release from sarcoplasmic reticulum (SR). Alternatively, PC can evoke dissipation of mitochondrial potential (ΔΨm) and mitochondrial permeability transition pore (mPTP). Here, to dissect the complex nature of PC action on Ca2+ homeostasis and oxidative phosphorylation (OXPHOS) in cardiomyocytes and mitochondria, the methods of fluorescent microscopy, perforated path-clamp, and mitochondrial assays were used. We found that LCAC in dose-dependent manner can evoke Ca2+-sparks and oscillations, long-living Ca2+ enriched microdomains, and, finally, Ca2+ overload leading to hypercontracture and cardiomyocyte death. Collectively, PC-driven cardiotoxicity involves: (I) redistribution of Ca2+ from SR to mitochondria with minimal contribution of external calcium influx; (II) irreversible inhibition of Krebs cycle and OXPHOS underlying limited mitochondrial Ca2+ buffering; (III) induction of mPTP reinforced by PC-calcium interplay; (IV) activation of Ca2+-dependent phospholipases cPLA2 and PLC. Based on the inhibitory analysis we may suggest that simultaneous inhibition of both phospholipases could be an effective strategy for protection against PC-mediated toxicity in cardiomyocytes.

Activation of forkhead box O3a by mono(2-ethylhexyl)phthalate and its role in protection against mono(2-ethylhexyl)phthalate-induced oxidative stress and apoptosis in human cardiomyocytes.

Mono(2-ethylhexyl)phthalate (MEHP), the active metabolite of di(2-ethylhexyl)phthalate (DEHP), is known to exert cardiotoxicity. The aim of the present study was to investigate the role of forkhead box O3a (FOXO3a) in MEHP-induced human AC16 cardiomyocyte injuries. MEHP reduced cell viability and mitochondrial membrane potential (ΔΨm), whereas it increased lactate dehydrogenase (LDH) leakage, production of reactive oxygen species (ROS), and apoptosis in cardiomyocytes. The expression of FOXO3a and its target genes, mitochondrial superoxide dismutase (Mn-SOD) and apoptosis repressor with caspase recruitment domain (ARC), increased after MEHP exposure, but the expression of p-FOXO3a protein was decreased. Overexpression of FOXO3a decreased the production of ROS and the apoptosis rate induced by MEHP, and the expression of Mn-SOD and ARC was further increased after MEHP exposure. In contrast, knockdown of FOXO3a resulted in increased ROS production and apoptosis and suppressed the expression of Mn-SOD and ARC in the presence of MEHP. However, overexpression or knockdown of FOXO3a did not affect MEHP-induced loss of ΔΨm. In conclusion, the loss of ΔΨm and apoptosis are involved in MEHP-induced cardiomyocyte toxicity. Activation of FOXO3a defends against MEHP-induced oxidative stress and apoptosis by upregulating the expression of Mn-SOD and ARC in AC16 cardiomyocytes.

Perfluorooctane sulfonate induced toxicity in embryonic stem cell-derived cardiomyocytes via inhibiting autophagy-lysosome pathway

Perfluorooctane sulfonate (PFOS), a classic environmental pollutant, is reported to cause cardiotoxicity in animals and humans. It has been demonstrated that PFOS exposure down-regulates expression of cardiac-development related genes and proteins. However, the related mechanism of PFOS has not been fully elucidated. In the present study, the embryonic stem (ES) cells-derived cardiomyocytes (ESC-CMs) was employed to investigate PFOS-mediated mechanism in developmental toxicity of cardiomyocytes. Our previous study shows that PFOS induces cardiomyocyte toxicity via causing mitochondrial damage. Nevertheless, the underlying mechanism by which PFOS affects the autophagy-related mitochondrial toxicity in ESC-CMs remains unclear. Here, we found that PFOS induced the swelling of mitochondria and the autophagosome accumulation in ESC-CMs at 40 μM concentration. PFOS increased the levels of LC3-II, p62, and ubiquitinated proteins. PFOS also induced an increase of LC3 and p62 localization into mitochondria, indicating that mitophagy degradation was impaired. The results of autophagic flux using chloroquine and RFP-GFP-LC3 analysis showed that the accumulation of autophagosome was not caused by the formation but by the impaired degradation. PFOS was capable of blocking the fusion between autophagosome and lysosome. PFOS caused dysfunction of lysosomes because it down-regulated Lamp2a and cathepsin D, but it did not induced lysosome membrane permeabilization. Meanwhile, PFOS-mediated lysosomal function and the inhibitory effect of autophagic flux could be reversed by PP242 at 40 nM concentration, an mTOR inhibitor. Furthermore, PP242 restored PFOS-induced ATP depletion and mitochondrial membrane potential. In conclusion, PFOS induced mitochondrial dysfunction via blocking autophagy-lysosome degradation, leading to cardiomyocyte toxicity from ES cells.

Quantifying drug-induced structural toxicity in hepatocytes and cardiomyocytes derived from hiPSCs using a deep learning method

Cardiac and hepatic toxicity result from induced disruption of the functioning of cardiomyocytes and hepatocytes, respectively, which is tightly related to the organization of their subcellular structures. Cellular structure can be analyzed from microscopy imaging data. However, subtle or complex structural changes that are not easily perceived may be missed by conventional image-analysis techniques. Here we report the evaluation of PhenoTox, an image-based deep-learning method of quantifying drug-induced structural changes using human hepatocytes and cardiomyocytes derived from human induced pluripotent stem cells. We assessed the ability of the deep learning method to detect variations in the organization of cellular structures from images of fixed or live cells. We also evaluated the power and sensitivity of the method for detecting toxic effects of drugs by conducting a set of experiments using known toxicants and other methods of screening for cytotoxic effects. Moreover, we used PhenoTox to characterize the effects of tamoxifen and doxorubicin—which cause liver toxicity—on hepatocytes. PhenoTox revealed differences related to loss of cytochrome P450 3A4 activity, for which it showed greater sensitivity than a caspase 3/7 assay. Finally, PhenoTox detected structural toxicity in cardiomyocytes, which was correlated with contractility defects induced by doxorubicin, erlotinib, and sorafenib. Taken together, the results demonstrated that PhenoTox can capture the subtle morphological changes that are early signs of toxicity in both hepatocytes and cardiomyocytes.

Human Amnion Membrane Proteins Prevent Doxorubicin-Induced Oxidative Stress Injury and Apoptosis in Rat H9c2 Cardiomyocytes.

Doxorubicin (DOX) is widely used as an effective chemotherapy agent in cancer treatment. Cardiac toxicity in cancer treatment with DOX demand urgent attention and no effective treatment has been established for DOX-induced cardiomyopathy. It has been well documented that human amniotic membrane proteins (AMPs), extracted from amnion membrane (AM), have antioxidant, anti-apoptotic, and cytoprotective properties. Therefore, in this study, we aimed to investigate the protective effects of AMPs against cardiotoxicity induced by DOX in cultured rat cardiomyocyte cells (H9c2). DOX-induced cell injury was evaluated using multi-parametric assay including thiazolyl blue tetrazolium bromide (MTT), the release of lactic dehydrogenase (LDH), intracellular Ca2+ , reactive oxygen species (ROS) levels, cellular antioxidant status, mitochondrial membrane potential (ΔΨm), malondialdehyde (MDA), and NF-κB p65 DNA-binding activity. Moreover, expression profiling of apoptosis-related genes (P53, Bcl-2, and Bax) and Annexin V by flow cytometry were used for cell apoptosis detection. It was shown that AMPs pretreatment inhibited the cell toxicity induced by DOX. AMPs effectively attenuated the increased levels of LDH, Ca2+ , ROS, and MDA and also simultaneously elevated the ΔΨm and antioxidant status such as superoxide dismutase (SOD) and Catalase (CAT) in pretreated H9c2 cardiomyocytes. Besides, the activity of NF-kB p65 was reduced and the p53 and Bax protein levels were inhibited in these myocardial cells subjected to DOX. These findings provide the first evidence that AMPs potently suppressed DOX-induced toxicity in cardiomyocytes through inhibition of oxidative stress and apoptosis. Thus, AMPs can be a potential therapeutic agent against DOX cardiotoxicity.

Protective effect of bacterial lipase on lipopolysaccharide-induced toxicity in rat cardiomyocytes; H9C2 cell line.

Introduction: Cardiovascular system is highly sensitive to LPS-induced oxidative damage. This study aimed to show the inhibitory effect of bacterial Lipase on LPS-induced cardiomyoblasts toxicity. Methods: Rat cardiomyoblasts H9C2 were classified into Control, LPS (cells received 0.1, 1 and 10 μg/mL LPS) and LPS+ Lipase groups. In LPS+Lipase group, different concentrations of lipopolysaccharide were pre-incubated with 5 mg/mL bacterial lipase at 37˚C overnight prior to cell treatment. After 72 hours, cell viability was assessed by MTT assay. The expression of key genes related to toll-like receptor signaling pathways was assessed by real-time PCR assay. Percentage of fatty acids was evaluated in each group using gas chromatography assay. The levels of NO was also measured using the Griess reaction. Results: Data showed H9C2 cells viability was decreased after exposure to LPS in a dose-dependent manner (P < 0.05). Incubation of LPS with lipase increased cell survival rate and closed to near-to-control levels (P < 0.05). Lipase had the potential to blunt the increased expression of IRAK and NF-κB in cells after exposure to the LPS. Compared to the LPS group, lipase attenuated the increased level of NO-induced by LPS (P < 0.05). Gas chromatography analysis showed the reduction of saturated fatty acids in cells from LPS group while the activity of lipase prohibited impact of LPS on cell fatty acid composition. LPS decreased the ability of cardiomyoblasts to form colonies. Incubation of LPS with lipase enhanced clonogenic capacity. Conclusion: Reduction in lipopolysaccharide-induced cytotoxicity is possibly related to lipase activity and reduction of modified lipopolysaccharide with toll-like receptor.

Bruton tyrosine-kinase inhibitor on the rise: acalabrutinib in Waldenström macroglobulinemia

Bruton tyrosine-kinase inhibitor on the rise: acalabrutinib in Waldenström macroglobulinemia

LncRNA PVT1 aggravates doxorubicin-induced cardiomyocyte apoptosis by targeting the miR-187-3p/AGO1 axis

ObjectivesTo investigate the effect of long non-coding (lnc) RNA PVT1 on apoptosis induced by doxorubicin-induced cardiotoxicity. MethodsWe analyzed the expression levels of lncRNA PVT1, miR-187-3p, using reverse transcription real-time quantitative PCR (RT-qPCR) in doxorubicin-treated cardiomyocytes. The mechanism of lncRNA PVT1 in cardiotoxicity was investigated using cell transfection, CCK-8, flow cytometry, Western blot, and dual-luciferase reporter assays. ResultsDoxorubicin promotes H9c2 apoptosis and increased PVT1 expression in cardiomyocytes. Knockdown of PVT1 attenuated doxorubicin-induced cardiomyocyte apoptosis. We found that miR-187-3p is a direct target of PVT1, and that lncRNA PVT1 adsorbs miR-187-3p by sponge action, reducing miR-187-3p levels. miR-187-3p negatively regulates AGO1, and PVT1 regulates AGO1 expression by targeting miR-187-3p, thereby regulating apoptosis. In addition, we knocked down AGO1 in H9c2 cells transfected with the miR-187-3p inhibitor, and found that it inhibited apoptosis. ConclusionIn doxorubicin-induced cardiomyocyte toxicity, the highly expressed lncRNA PVT1 enhances the expression of AGO1 by sponge adsorption of miR-187-3p. Decreasing the expression of lncRNA PVT1 inhibits the adsorption of miR-187-3p through competing endogenous (ce) RNA, thereby reducing the expression of AGO1 and decreasing the apoptosis of cardiomyocytes.

Why the Diagnosis of ATTR-Cardiomyopathy May Be a Challenge for Physicians

Cardiac amyloidosis is a rare but life-threatening group of disorders caused by the extracellular deposition of misfolded amyloid fibrils in cardiac tissue. Amyloid accumulation leads to cardiomyocyte toxicity, extracellular volume expansion, and ventricular pseudohypertrophy. Two types of amyloid protein are thought to be responsible for most disorders: immunoglobulin light chain, which causes light chain amyloidosis (AL); and transthyretin (TTR), which causes transthyretin amyloidosis (ATTR), of which there are two types: hereditary (hATTR) or wild-type (ATTRwt). Despite increasing clinical recognition of the disease, cardiac amyloidosis remains underdiagnosed. This article explores the epidemiology of AL and ATTR and the noninvasive techniques that help to improve diagnosis of the disorder. Cardiac amyloidosis is associated with mixed phenotype symptoms of polyneuropathy and cardiomyopathy which can lead to multiple misdiagnoses. As a result, patients can wait between 2 and 4 years for a correct diagnosis. Early diagnosis may be aided by recognising red flag symptom clusters. These include family history; neuropathy and sensory involvement; bilateral carpal tunnel syndrome; early autonomic dysfunction and gastrointestinal complaints; heart failure (HF) with preserved ejection fraction (HFpEF; without hypertension); cardiac hypertrophy, arrhythmias, ventricular blocks, right-sided or biventricular HF, or cardiomyopathy; renal abnormalities; and vitreous opacities. Noninvasive imaging techniques have increasingly been used as an alternative to biopsy to diagnose cardiac amyloidosis with the hope of allowing physicians to provide targeted therapy for these patients. Techniques include speckle tracking echocardiography, cardiac MRI, and nuclear scintigraphy, together with biomarkers such as N-terminal pro-brain natriuretic peptide and hepatocyte growth factor (HGF). It is hoped that greater understanding of patients with ATTR may lead to increased awareness of the disorder and improve patient outcomes.

Novel Screening Method Identifies PI3Kα, mTOR, and IGF1R as Key Kinases Regulating Cardiomyocyte Survival.

BackgroundSmall molecule kinase inhibitors (KIs) are a class of agents currently used for treatment of various cancers. Unfortunately, treatment of cancer patients with some of the KIs is associated with cardiotoxicity, and there is an unmet need for methods to predict their cardiotoxicity. Here, we utilized a novel computational method to identify protein kinases crucial for cardiomyocyte viability.Methods and ResultsOne hundred forty KIs were screened for their toxicity in cultured neonatal cardiomyocytes. The kinase targets of KIs were determined based on integrated data from binding assays. The key kinases mediating the toxicity of KIs to cardiomyocytes were identified by using a novel machine learning method for target deconvolution that combines the information from the toxicity screen and from the kinase profiling assays. The top kinases identified by the model were phosphoinositide 3‐kinase catalytic subunit alpha, mammalian target of rapamycin, and insulin‐like growth factor 1 receptor. Knockdown of the individual kinases in cardiomyocytes confirmed their role in regulating cardiomyocyte viability.ConclusionsCombining the data from analysis of KI toxicity on cardiomyocytes and KI target profiling provides a novel method to predict cardiomyocyte toxicity of KIs.