Tranilast prevents doxorubicin-induced myocardial hypertrophy and angiotensin II synthesis in rats

Molecular mechanisms of endothelial remodeling under doxorubicin treatment

Doxorubicin (DOX) is an effective antineoplastic agent used to treat various types of cancers. However, its use is limited by the development of cardiotoxicity, which may result in heart failure. The exact mechanisms underlying DOX-induced cardiotoxicity are not fully understood, but recent studies have shown that endothelial-mesenchymal transition (EndMT) and endothelial damage play a crucial role in this process. EndMT is a biological process in which endothelial cells lose their characteristics and transform into mesenchymal cells, which have a fibroblast-like phenotype. This process has been shown to contribute to tissue fibrosis and remodeling in various diseases, including cancer and cardiovascular diseases. DOX-induced cardiotoxicity has been demonstrated to increase the expression of EndMT markers, suggesting that EndMT may play a critical role in the development of this condition. Furthermore, DOX-induced cardiotoxicity has been shown to cause endothelial damage, leading to the disruption of the endothelial barrier function and increased vascular permeability. This can result in the leakage of plasma proteins, leading to tissue edema and inflammation. Moreover, DOX can impair the production of nitric oxide, endothelin-1, neuregulin, thrombomodulin, thromboxane B2 etc. by endothelial cells, leading to vasoconstriction, thrombosis and further impairing cardiac function. In this regard, this review is devoted to the generalization and structuring of information about the known molecular mechanisms of endothelial remodeling under the action of DOX.

Tranilast reduces cardiomyocyte injury induced by ischemia‑reperfusion via Nrf2/HO‑1/NF‑κB signaling

Tranilast, a synthetic derivative of a tryptophan metabolite, can be used to treat heart diseases. However, the specific mechanism underlying the effect of tranilast on ischemia-reperfusion (I/R) injury-induced cardiomyocyte apoptosis remains unclear. Therefore, the present study aimed to determine if tranilast could attenuate I/R-induced cardiomyocyte injury. A hypoxia/reoxygenation (H/R) model of H9c2 cardiomyocytes was established to simulate I/R-induced cardiomyocyte injury. The viability, apoptosis, inflammation and oxidative stress in H/R-induced H9c2 cells following treatment with tranilast were evaluated by Cell Counting Kit-8 and TUNEL assay. Commercially available kits were used to detect the levels of inflammatory markers and oxidative stress indicators. In addition, the expression levels of the apoptosis- and nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1)/NF-κB signalling pathway-associated proteins were detected by western blotting. The levels of reactive oxygen species were determined using 2',7'-dichlorofluorescin diacetate assay kit. The viability of H9c2 cells was decreased following induction with H/R. However, treatment with tranilast increased viability while decreasing apoptosis, oxidative stress and inflammatory response in H/R-induced H9c2 cells by activating Nrf2/HO-1/NF-κB signalling. Furthermore, treatment with ML-385, an Nrf2 inhibitor, reversed the effects of tranilast on H/R-induced H9c2 cells. In conclusion, the results of the present study suggested that tranilast could attenuate I/R-induced cardiomyocyte injury via the Nrf2/HO-1/NF-κB signalling pathway.

Metformin Alleviates Epirubicin-Induced Endothelial Impairment by Restoring Mitochondrial Homeostasis

Vascular endothelial injury is important in anthracycline-induced cardiotoxicity. Anthracyclines seriously damage the mitochondrial function and mitochondrial homeostasis. In this study, we investigated the damage of epirubicin to vascular endothelial cells and the protective role of metformin from the perspective of mitochondrial homeostasis. We found that epirubicin treatment resulted in DNA double-strand breaks (DSB), elevated reactive oxygen species (ROS) production, and excessive Angiotensin II release in HUVEC cells. Pretreatment with metformin significantly mitigated the injuries caused by epirubicin. In addition, inhibited expression of Mitochondrial transcription factor A (TFAM) and increased mitochondria fragmentation were observed in epirubicin-treated cells, which were partially resumed by metformin pretreatment. In epirubicin-treated cells, knockdown of TFAM counteracted the attenuated DSB formation due to metformin pretreatment, and inhibition of mitochondrial fragmentation with Mdivi-1 decreased DSB formation but increased TFAM expression. Furthermore, epirubicin treatment promoted mitochondrial fragmentation by stimulating the expression of Dynamin-1-like protein (DRP1) and inhibiting the expression of Optic atrophy-1(OPA1) and Mitofusin 1(MFN1), which could be partially prevented by metformin. Finally, we found metformin could increase TFAM expression and decrease DRP1 expression in epirubicin-treated HUVEC cells by upregulating the expression of calcineurin/Transcription factor EB (TFEB). Taken together, this study provided evidence that metformin treatment was an effective way to mitigate epirubicin-induced endothelial impairment by maintaining mitochondrial homeostasis.

Network Pharmacology and In Vitro Experimental Verification Reveal the Mechanism of the Hirudin in Suppressing Myocardial Hypertrophy

Background: Myocardial hypertrophy is a complex pathological process, which is a common manifestation during the development of various cardiovascular diseases. Hirudin has been shown to have therapeutic effects on a variety of cardiovascular diseases, however, its therapeutic effect on myocardial hypertrophy is still unknown, and its chemical and pharmacological characteristics remain to be elucidated.

Methods: In this study, the network pharmacology method was used to characterize the mechanism of hirudin on myocardial hypertrophy. The potential protein targets of hirudin and myocardial hypertrophy were both obtained from the Genecards database, and potential pathways associated with genes were identified by Gene Ontology and pathway enrichment analysis, and the data were displayed in a visual manner. Subsequently, the potential mechanism of action of hirudin on myocardial hypertrophy predicted by network pharmacology analysis was verified by molecular docking, and finally, the main findings were further verified by in vitro experiments by molecular biology techniques. Based on the results obtained from the study of H9c2 cell line, the inhibitory effect of hirudin on myocardial hypertrophy was further proved in the primary rat cardiomyocytes.

Results: A total of 250 targets of hirudin, and 5,376 targets related to myocardial hypertrophy after deduplication were collected. The drug-disease network showed the relationship between hirudin, myocardial hypertrophy, and the targets. Further, systematic analysis from the PPI network indicated that blood coagulation, vesicle lumen, and signaling receptor activator activity may be the potential mechanisms of hirudin in the treatment of myocardial hypertrophy, and the PI3K/AKT signaling pathway may be the most relevant to the therapeutic effect of hirudin. Then, three therapeutic targets that were highly related to myocardial hypertrophy were extracted. Hirudin can be highly bound to STAT3, IL-6, and MAPK1 and found by molecular docking, which may be the basis for its inhibitory effect on myocardial hypertrophy. In addition, in vitro experiments showed that hirudin could inhibit AngII-induced hypertrophy and death of H9c2 cells, and significantly reduce the mRNA and protein expression levels of STAT3, MAPK1, and IL-6. The above conclusions were verified in primary rat cardiomyocytes.

Conclusion: Hirudin can be used to treat myocardial hypertrophy through a complex mechanism. The application of network pharmacology and experimental validation can promote the application of hirudin in cardiovascular diseases and the interpretation and understanding of molecular biological mechanisms.

Hydrogen Attenuates Thyroid Hormone-Induced Cardiac Hypertrophy in Rats by regulating angiotensin II type 1 receptor and NADPH oxidase 2 mediated oxidative stress

Cardiac hypertrophy occurs as a result of high levels of thyroid hormone, which may contribute to heart failure and is closely related to oxidative stress. Hydrogen is a good antioxidant. In this study, we found that intragastric levothyroxine administration for two weeks caused obvious cardiac hypertrophy without reduced systolic function. Additionally, hydrogen inhalation ameliorated the levothyroxine-induced metabolic increase and cardiac hypertrophy in rats. Serum brain natriuretic peptide expression was also attenuated by hydrogen treatment. However, hydrogen had no significant effect on levothyroxine -induced serum troponin I and serum thyroid hormone changes. Hydrogen treatment also reduced the levothyroxine-induced increase in cardiac malondialdehyde, 8-hydroxy-2-deoxyguanosine and serum hydrogen peroxide levels and upregulated superoxide dismutase and glutathione peroxidase activity. Additionally, western blotting results showed that hydrogen inhalation inhibited the expression of cardiac nicotinamide adenine dinucleotide phosphate oxidase 2 (NOX2), angiotensin II type 1 receptor, sarcoplasmic reticulum Ca²⁺-ATPase (SERCA2), phospho-phospholamban and α-myosin heavy chain proteins. In conclusion, the present study revealed a protective effect of hydrogen on levothyroxine -induced cardiac hypertrophy by regulating angiotensin II type 1 receptors and NOX2-mediated oxidative stress in rats.

Tranilast abrogates cisplatin-induced testicular and epididymal injuries: An insight into its modulatory impact on apoptosis/proliferation

Cisplatin is a chemotherapeutic agent whose therapeutic use is greatly limited by the associated organs' toxicity and particularly, testicular toxicity. Cisplatin-induced testicular damage reported being mediated through mitochondria-mediated apoptosis, inflammation, and oxidative stress. Evidence showed that tranilast (TRN) has the ability to restore the oxidative status and modulate TRAIL/caspase-8 signaling. This led us to hypothesize that TRN could abrogate cisplatin-induced testicular and epididymal injuries via inhibiting oxidative stress and modulating proliferation and TRAIL/caspase-8/cJNK signaling. Cisplatin injection induced oligospermia and abnormalities in testicular and epididymal structure along with impaired oxidative status. TRN administration (100 or 300 mg/kg) for 7 days post-cisplatin injection preserved spermatogenesis and restored testicular and epididymal architecture, but restoration was more so in TRN300 than TRN100. This was in line with the restoration of balanced oxidative status as indicated by the increased total antioxidant capacity, glutathione and superoxide dismutase activity, and the decreased malondialdehyde content in testes (p < 0.05 vs. cisplatin). TRN increased the cell proliferation revealed by the increased expression of proliferating cell nuclear antigen in a dose-dependent manner (p < 0.05 vs. cisplatin) whereas only TRN300 decreased testicular cJNK, TRAIL, and caspase-8 expression (p < 0.05 vs. cisplatin). Moreover, TRN dose-dependently inhibited the pro-inflammatory transcription factor NF-kB and the cytokine TNF-α expressions in testes. In conclusion, TRN300 was more effective than TRN100 in alleviating cisplatin-induced testicular and epididymal injuries and in enhancing spermatogenesis. This curative effect of TRN might be mediated through its antioxidant and anti-inflammatory impacts along with its modulatory impact on cJNK/TRAIL/caspase-8 signaling favoring proliferation rather than apoptosis.

Doxorubicin-induced cardiotoxicity: An update on the molecular mechanism and novel therapeutic strategies for effective management

Doxorubicin (Dox) is a secondary metabolite of the mutated strain of Streptomyces peucetius var. Caesius and belongs to the anthracyclines family. The anti-cancer activity of Dox is mainly exerted through the DNA intercalation and inhibiting topoisomerase II enzyme in fast-proliferating tumors. However, Dox causes cumulative and dose-dependent cardiotoxicity, which results in increased risks of mortality among cancer patients and thus limiting its wide clinical applications. There are several mechanisms has been proposed for doxorubicin-induced cardiotoxicity and oxidative stress, free radical generation and apoptosis are most widely reported. Apart from this, other mechanisms are also involved in Dox-induced cardiotoxicity such as impaired mitochondrial function, a perturbation in iron regulatory protein, disruption of Ca²⁺ homeostasis, autophagy, the release of nitric oxide and inflammatory mediators and altered gene and protein expression that involved apoptosis. Dox also causes downregulation of DNA methyltransferase 1 (DNMT1) enzyme activity which leads to a reduction in the DNA methylation process. This hypomethylation causes dysregulation in the mitochondrial genes like peroxisome proliferator-activated receptor-gamma coactivator (PGC)-1-alpha (PGC-1α), nuclear respiratory factor 1 (NRF-1) and mitochondrial transcription factor A (TFAM) unit in the heart. Apart from DNA methylation, Dox treatment also alters the micro RNAs levels and histone deacetylase (HDAC) activity. Therefore, in the current review, we have provided a detailed update on the current understanding of the pathological mechanisms behind the well-known Dox-induced cardiotoxicity. Further, we have provided some of the most plausible pharmacological strategies which have been tested against Dox-induced cardiotoxicity.

Effects of Tranilast on Inflammasome and Macrophage Phenotype in a Mouse Model of Myocardial Infarction

Acute myocardial infarction (AMI) has been a devastating actuality and accounts for half of cardiovascular emergency department visits. Nucleotide oligomerization domain, leucine-rich repeat, and pyrin domain-containing protein 3 (NLRP3) inflammasome participates in the mediation of myocardial inflammation during AMI. Therefore, this study aimed to reveal the therapeutic function of tranilast, an agent targeting NLRP3, for AMI. AMI mouse model was first established by transient myocardial ischemia. Western blot and quantitative reverse transcription polymerase chain reaction assay were performed to estimate the expression levels of related genes. Flow cytometry was used to analyze the macrophage types, and the therapeutic effects of tranilast were estimated by echocardiographic analysis and Masson's trichrome stain. We demonstrated that AMI induced the activation of NLRP3 inflammasome in the heart tissues of mice with AMI. Tranilast decreased the expression of interleukin-1β and cleaved caspase-1 in bone marrow-derived macrophages and thus re-educated M1-macrophages toward the M2-phenotype both in vitro and in vivo. Tranilast inhibited the activation in the heart tissues of AMI mice and thus improved cardiac functional recovery in the AMI mouse model. In conclusion, we revealed that tranilast ameliorated myocardial infarction by inhibiting NLRP3 inflammasome and re-educating macrophage phenotype in this study.