Protection against doxorubicin-induced myocardial dysfunction in mice by cardiac-specific expression of carboxyl terminus of hsp70-interacting protein

Crosstalk between ubiquitin ligases and ncRNAs drives cardiovascular disease progression

Cardiovascular diseases (CVDs) are multifactorial chronic diseases and have the highest rates of morbidity and mortality worldwide. The ubiquitin-proteasome system (UPS) plays a crucial role in posttranslational modification and quality control of proteins, maintaining intracellular homeostasis via degradation of misfolded, short-lived, or nonfunctional regulatory proteins. Noncoding RNAs (ncRNAs, such as microRNAs, long noncoding RNAs, circular RNAs and small interfering RNAs) serve as epigenetic factors and directly or indirectly participate in various physiological and pathological processes. NcRNAs that regulate ubiquitination or are regulated by the UPS are involved in the execution of target protein stability. The cross-linked relationship between the UPS, ncRNAs and CVDs has drawn researchers' attention. Herein, we provide an update on recent developments and perspectives on how the crosstalk of the UPS and ncRNAs affects the pathological mechanisms of CVDs, particularly myocardial ischemia/reperfusion injury, myocardial infarction, cardiomyopathy, heart failure, atherosclerosis, hypertension, and ischemic stroke. In addition, we further envision that RNA interference or ncRNA mimics or inhibitors targeting the UPS can potentially be used as therapeutic tools and strategies.

Pathological mutations reveal the key role of the cytosolic iRhom2 N-terminus for phosphorylation-independent 14-3-3 interaction and ADAM17 binding, stability, and activity

The protease ADAM17 plays an important role in inflammation and cancer and is regulated by iRhom2. Mutations in the cytosolic N-terminus of human iRhom2 cause tylosis with oesophageal cancer (TOC). In mice, partial deletion of the N-terminus results in a curly hair phenotype (cub). These pathological consequences are consistent with our findings that iRhom2 is highly expressed in keratinocytes and in oesophageal cancer. Cub and TOC are associated with hyperactivation of ADAM17-dependent EGFR signalling. However, the underlying molecular mechanisms are not understood. We have identified a non-canonical, phosphorylation-independent 14-3-3 interaction site that encompasses all known TOC mutations. Disruption of this site dysregulates ADAM17 activity. The larger cub deletion also includes the TOC site and thus also dysregulated ADAM17 activity. The cub deletion, but not the TOC mutation, also causes severe reductions in stimulated shedding, binding, and stability of ADAM17, demonstrating the presence of additional regulatory sites in the N-terminus of iRhom2. Overall, this study contrasts the TOC and cub mutations, illustrates their different molecular consequences, and reveals important key functions of the iRhom2 N-terminus in regulating ADAM17.

Upregulation of TRIM16 mitigates doxorubicin-induced cardiotoxicity by modulating TAK1 and YAP/Nrf2 pathways in mice

The clinic application of doxorubicin (DOX) is severely limited by its severe cardiotoxicity. Tripartite motif-containing protein 16 (TRIM16) has E3 ubiquitin ligase activity and is upregulated in cardiomyocytes under pathological stress, yet its role in DOX-induced cardiotoxicity remains elusive. This study aims to investigate the role and mechanism of TRIM16 in DOX cardiotoxicity. Following TRIM16 overexpression in hearts with AAV9-TRIM16, mice were intravenously administered DOX at a dose of 4 mg/kg/week for 4 weeks to assess the impact of TRIM16 on doxorubicin-induced cardiotoxicity. Transfection of OE-TRIM16 plasmids and siRNA-TRIM16 was performed in neonatal rat cardiomyocytes (NRCMs). Our results revealed that DOX challenge elicited a significant upregulation of TRIM16 proteins in cardiomyocytes. TRIM16 overexpression efficiently ameliorated cardiac function while suppressing inflammation, ROS generation, apoptosis and fibrosis provoked by DOX in the myocardium. TRIM16 knockdown exacerbated these alterations caused by DOX in NRCMs. Mechanistically, OE-TRIM16 augmented the ubiquitination and degradation of p-TAK1, thereby arresting JNK and p38MAPK activation evoked by DOX in cardiomyocytes. Furthermore, DOX enhanced the interaction between p-TAK1 and YAP1 proteins, resulting in a reduction in YAP and Nrf2 proteins in cardiomyocytes. OE-TRIM16 elevated YAP levels and facilitated its nuclear translocation, thereby promoting Nrf2 expression and mitigating oxidative stress and inflammation. This effect was nullified by siTRIM16 or TAK1 inhibitor Takinib. Collectively, the current study elaborates that upregulating TRIM16 mitigates DOX-induced cardiotoxicity through anti-inflammation and anti-oxidative stress by modulating TAK1-mediated p38 and JNK as well as YAP/Nrf2 pathways, and targeting TRIM16 may provide a novel strategy to treat DOX-induced cardiotoxicity.

Angiotensin-(1-9) attenuates adriamycin-induced cardiomyopathy in rats via the angiotensin type 2 receptor

Adriamycin (ADR) causes irreversible damage to the heart, leading to ADR-induced cardiomyopathy (ACM). Angiotensin-(1-9) [Ang-(1-9)] is a peptide from the counter-regulatory renin-angiotensin system, but the effects on ACM is unclear. Our study was aimed to explore the effects and underlying molecular mechanisms of Ang-(1-9) against ACM in Wistar rats. Rats were injected intraperitoneally with ADR via six equal doses (each containing 2.5 mg/kg) within a period of 2 weeks to induce ACM. After 2 weeks of ADR treatment, the rats were treated with Ang-(1-9) (200 ng/kg/min) or angiotensin type 2 receptor (AT2R) antagonist PD123319 (100 ng/kg/min) for 4 weeks. Although Ang-(1-9) treatment did not influence blood pressure, it significantly improved left ventricular function and remodeling in ADR-treated rats, by inhibiting collagen deposition, the expression of TGF-β1, inflammatory response, cardiomyocyte apoptosis and oxidative stress. Moreover, Ang-(1-9) reduced ERK1/2 and P38 MAPK phosphorylation. The therapeutic effects of Ang-(1-9) were blocked by the AT2R antagonist PD123319, which also offset the down-regulation protein expression of pERK1/2 and pP38 MAPK induced by Ang-(1-9). These data suggest that Ang-(1-9) improved left ventricular function and remodeling in ADR-treated rats by an AT2R/ ERK1/2 and P38 MAPK-dependent mechanism. Thus, the Ang-(1-9)/AT2R axis may provide a novel and promising target to the prevention and treatment of ACM.

Protective effect of Pueraria lobata leaves on doxorubicin-induced myocardial infarction in experimental Wistar rats

The present study intended to explore the preventive effects of Pueraria lobata leaves against doxorubicin (DOX)-induced myocardial infarction (MI) in Wistar rats. The rats were separated into four groups, with each group containing six rats. Group I control rats; group II received DOX-alone in six equivalent injections for 2 weeks; group III received DOX as abovementioned with P. lobata oral administration for 2 weeks; group IV received P. lobata alone for 2 weeks. At the end of the experiment, postcervical dislocation and MI induced by DOX were determined on the basis of the variations in the animal body and heart weight and further instabilities in cardiac marker enzymes aspartate transaminase, lactate dehydrogenase, creatine kinase, creatine kinase-myoglobin binding, and cardiac troponin I in the serum. At the same time, for group III animals, which were exposed to P. lobata, all the above-denoted marker levels were maintained. Levels of some crucial heart-binding proteins like heart fatty acid binding protein, monocyte chemoattractant protein-1, and transforming growth factor beta were elevated in DOX-alone treated rats. Additionally, group III animals treated with P. lobata showed some preventive downregulated expressions of these binding proteins. Histopathological observations also revealed the preventive effect of P. lobata. Ultimately proteins tangled in the phosphoinositide 3-kinase/protein kinase B pathway were studied by Western blot. P. lobata treatment downregulated the inflammatory markers. The findings suggest that P. lobata exhibits cardioprotective effect on MI.

STUB1/CHIP: New insights in cancer and immunity

The STUB1 gene (STIP1 homology and U-box-containing protein 1), located at 16q13.3, encodes the CHIP (carboxyl terminus of Hsc70-interacting protein), an essential E3 ligase involved in protein quality control. CHIP comprises three domains: an N-terminal tetratricopeptide repeat (TPR) domain, a middle coiled-coil domain, and a C-terminal U-box domain. It functions as a co-chaperone for heat shock protein (HSP) via the TPR domain and as an E3 ligase, ubiquitinating substrates through its U-box domain. Numerous studies suggest that STUB1 plays a crucial role in various physiological process, such as aging, autophagy, and bone remodeling. Moreover, emerging evidence has shown that STUB1 can degrade oncoproteins to exert tumor-suppressive functions, and it has recently emerged as a novel player in tumor immunity. This review provides a comprehensive overview of STUB1's role in cancer, including its clinical significance, impact on tumor progression, dual roles, tumor stem cell-like properties, angiogenesis, drug resistance, and DNA repair. In addition, we explore STUB1's functions in immune cell differentiation and maturation, inflammation, autoimmunity, antiviral immune response, and tumor immunity. Collectively, STUB1 represents a promising and valuable therapeutic target in cancer and immunology.

Upregulation of Biomarker Limd1 Was Correlated with Immune Infiltration in Doxorubicin-Related Cardiotoxicity

Doxorubicin is one of the most common antitumor drugs. However, cardiotoxicity's side effect limits its clinical applicability. In the present study, Gene Expression Omnibus (GEO) datasets were applied to reanalyze differentially expressed genes (DEGs) and construct weighted correlation network analysis (WGCNA) modules of doxorubicin-induced cardiotoxicity in wild-type mice. Several other bioinformatics analyses were performed to pick out the hub gene, and then the correlation between the hub gene and immune infiltration was evaluated. In total, 120 DEGs were discovered in a mouse model of doxorubicin-induced cardiotoxicity, and PF-04217903, propranolol, azithromycin, etc. were found to be potential drugs against this pathological condition. Among all the DEGs, 14 were further screened out by WGCNA modules, of which Limd1 was upregulated and finally regarded as the hub gene after being validated in other GEO datasets. Limd1 was upregulated in the peripheral blood mononuclear cell (PBMC) of the rat model, and the area under curve (AUC) of the receiver operating characteristic curve (ROC) in diagnosing cardiotoxicity was 0.847. The GSEA and PPI networks revealed a potential immunocyte regulatory role of Limd1 in cardiotoxicity. The proportion of "dendritic cells activated" in the heart was significantly elevated, while "macrophage M1" and "monocytes" declined after in vivo doxorubicin application. Finally, Limd1 expression was significantly positively correlated with "dendritic cells activation' and negatively correlated with "monocytes" and "macrophages M1'. In summary, our results suggested that limd1 is a valuable biomarker and a potential inflammation regulator in doxorubicin-induced cardiotoxicity.

The E3 ubiquitin ligase CHIP protects against sepsis-induced myocardial dysfunction by inhibiting NF-κB-mediated inflammation via promoting ubiquitination and degradation of karyopherin-α 2

Cardiac dysfunction has been recognized as a major contributor to mortality in sepsis, which is closely associated with inflammatory reactions. The carboxy terminus of Hsc70-interacting protein (CHIP), a U-box E3 ubiquitin ligase, defends against cardiac injury caused by other factors, but its role in sepsis-induced cardiac dysfunction has yet to be determined. The present study was designed to investigate the effects of CHIP on cardiac dysfunction caused by sepsis and the molecular mechanisms underlying these processes. We discovered that the CHIP level decreased gradually in the heart at different time points after septic model construction. The decline in CHIP expression of lipopolysaccharide (LPS)-stimulated cardiomyocytes was related to c-Jun activation that inhibited the transcription of CHIP. Functional biology experiments indicated that CHIP bound directly to karyopherin-α 2 (KPNA2) and promoted its degradation through polyubiquitination in cardiomyocytes. CHIP overexpression in cardiomyocytes obviously inhibited LPS-initiated release of TNF-α and IL-6 by promoting KPNA2 degradation, reducing NF-κB translocation into the nucleus. Consistent with the in vitro results, data obtained from animal experiments indicated that septic transgenic mice with heart-specific CHIP overexpression showed a weaker proinflammatory response and reduced cardiac dysfunction than septic control mice. Furthermore, we found that the therapeutic effect of compound YL-109 on cardiac dysfunction in septic mice was due to the upregulation of myocardial CHIP expression. These findings demonstrated that sepsis-initiated the activation of c-Jun suppressed CHIP transcription. CHIP directly promoted ubiquitin-mediated degradation of KPNA2, which reduced the production of proinflammatory cytokines by inhibiting the translocation of NF-κB from the cytoplasm into the nucleus in myocardium, thereby attenuating sepsis-induced cardiac dysfunction.

Phagocytosing differentiated cell-fragments is a novel mechanism for controlling somatic stem cell differentiation within a short time frame

Stem cells undergo cytokine-driven differentiation, but this process often takes longer than several weeks to complete. A novel mechanism for somatic stem cell differentiation via phagocytosing ‘model cells’ (apoptotic differentiated cells) was found to require only a short time frame. Pluripotent-like Muse cells, multipotent mesenchymal stem cells (MSCs), and neural stem cells (NSCs) phagocytosed apoptotic differentiated cells via different phagocytic receptor subsets than macrophages. The phagocytosed-differentiated cell-derived contents (e.g., transcription factors) were quickly released into the cytoplasm, translocated into the nucleus, and bound to promoter regions of the stem cell genomes. Within 24 ~ 36 h, the cells expressed lineage-specific markers corresponding to the phagocytosed-differentiated cells, both in vitro and in vivo. At 1 week, the gene expression profiles were similar to those of the authentic differentiated cells and expressed functional markers. Differentiation was limited to the inherent potential of each cell line: triploblastic-, adipogenic-/chondrogenic-, and neural-lineages in Muse cells, MSCs, and NSCs, respectively. Disruption of phagocytosis, either by phagocytic receptor inhibition via small interfering RNA or annexin V treatment, impeded differentiation in vitro and in vivo. Together, our findings uncovered a simple mechanism by which differentiation-directing factors are directly transferred to somatic stem cells by phagocytosing apoptotic differentiated cells to trigger their rapid differentiation into the target cell lineage.

Integrated multi-omics analysis of adverse cardiac remodeling and metabolic inflexibility upon ErbB2 and ERRα deficiency

Functional oncogenic links between ErbB2 and ERRα in HER2+ breast cancer patients support a therapeutic benefit of co-targeted therapies. However, ErbB2 and ERRα also play key roles in heart physiology, and this approach could pose a potential liability to cardiovascular health. Herein, using integrated phosphoproteomic, transcriptomic and metabolic profiling, we uncovered molecular mechanisms associated with the adverse remodeling of cardiac functions in mice with combined attenuation of ErbB2 and ERRα activity. Genetic disruption of both effectors results in profound effects on cardiomyocyte architecture, inflammatory response and metabolism, the latter leading to a decrease in fatty acyl-carnitine species further increasing the reliance on glucose as a metabolic fuel, a hallmark of failing hearts. Furthermore, integrated omics signatures of ERRα loss-of-function and doxorubicin treatment exhibit common features of chemotherapeutic cardiotoxicity. These findings thus reveal potential cardiovascular risks in discrete combination therapies in the treatment of breast and other cancers.

Murine hearts deficient in ErbB2 and/or ERRα are used to profile the adverse cardiac remodeling associated with potential targeted breast cancer treatments by phosphoproteomic, transcriptomic and metabolomic profiling.

Anthracycline-Induced Atrial Structural and Electrical Remodeling Characterizes Early Cardiotoxicity and Contributes to Atrial Conductive Instability and Dysfunction

Aims: Cancer patients treated with anthracyclines are susceptible to atrial fibrillation (AF), while the mechanisms remain unclear. Due to sudden and unpredictable features, prediction of anthracycline-induced AF at early phase is difficult. Clinically, we tested whether anthracycline-induced early atrial remodeling in patients could be detected by echocardiography. Experimentally, we investigated the mechanisms of doxorubicin-induced atrial remodeling and AF in mice, and the protective effects of dexrazoxane and antioxidants. Methods and Results: Postsurgery breast cancer patients with an anthracycline-containing or anthracycline exclusion regimen were recruited for echocardiography before chemotherapy, and 3 and 6 months after chemotherapy. Mice were injected with doxorubicin or vehicle (5 mg/kg/week, 4 weeks), and left atrial diameter, electrical transmission, and AF inducibility were measured. Meanwhile, the level of reactive oxygen species (ROS), activity of antioxidant enzymes, cardiomyocyte size, vacuolization, inflammation, and fibrosis were also measured in mouse atria. The therapeutic effects of dexrazoxane and antioxidants on doxorubicin-induced changes in the aforementioned parameters were also determined. While ventricular parameters and functions were unchanged in cancer patients receiving anthracyclines before and after chemotherapy, left atrial reservoir and conduit function were decreased at 3 months postchemotherapy versus prechemotherapy. Doxorubicin-induced susceptibility to AF occurred in mice before onset of ventricular dysfunction. Doxorubicin-induced AF was via inducing structural remodeling (cardiomyocyte death, hypotrophy, and vacuolization) and electrical remodeling (reduction and redistribution of connexin 43) in atria, which was effectively prevented by dexrazoxane or antioxidants through inhibiting ROS generation or enhancing ROS elimination. Innovation and Conclusion: AF inducibility was induced after doxorubicin injection, which can be inhibited by repressing the ROS level. Antioxid. Redox Signal. 37, 19-39. The Clinical Trial Registration number is PJ-KS-KY-2019-73.

Resolvin D1 Attenuates Doxorubicin-Induced Cardiotoxicity by Inhibiting Inflammation, Oxidative and Endoplasmic Reticulum Stress

Resolvin D1 (RvD1) is a lipid mediator that promotes resolution of inflammation. However, the function of RvD1 in doxorubicin- (Dox-) induced cardiotoxicity remains to be clarified. This study aimed to investigate whether RvD1 could attenuate Dox-induced cardiac injury. The mice were divided into three groups: control, Dox (20 mg/kg, once, intraperitoneally), and Dox + RvD1. RvD1 (2.5 μg/kg, intraperitoneally) was injected daily for 5 days. Echocardiography was performed to evaluate the cardiac function, and the heart tissue and serum samples were collected for further analyses. The results showed that RvD1 attenuated the decreased ratio of heart weight/body weight and heart weight/tibia length, the increased level of creatine kinase and activity of lactate dehydrogenase after Dox treatment. RvD1 improved the ejection fraction and fractional shortening of left ventricular and attenuated the severity of apoptosis induced by Dox. As for the underlying pathways, the results showed that RvD1 reduced the expression of IL-1 and IL-6, and attenuated the phosphorylation of P65 in cardiac tissue. RvD1 attenuated the oxidative stress induced by Dox, as demonstrated by the attenuated levels of superoxide dismutase, glutathione, and malondialdehyde, decreased expression of Nox-2 and Nox-4 and increased expression of Nrf-2 and HO-1. In addition, RvD1 also inhibited the endoplasmic reticulum stress induced by Dox. These results indicate the potential therapeutic benefits of RvD1 in Dox-induced cardiotoxicity in mice, and the mechanism may be related to the attenuated inflammation, oxidative stress and endoplasmic reticulum stress.

CHIP ameliorates cerebral ischemia-reperfusion injury by attenuating necroptosis and inflammation

Blood reperfusion of ischemic cerebral tissue may cause cerebral ischemia-reperfusion (CIR) injury. Necroptosis and inflammation have been demonstrated to be involved in the disease-related process of CIR injury. The E3 ubiquitin ligase carboxyl terminus of Hsp70-interacting protein (CHIP) can modulate multiple cellular signaling processes, including necroptosis and inflammation. Numerous studies have demonstrated the neuroprotective effects of CHIP on multiple central nervous system (CNS) diseases. However, the effects of CHIP on CIR injury have not been fully explored. We hypothesize that CHIP can exert neuroprotective effects by attenuating necroptosis and inflammation during CIR injury. In the present study, adult wild-type (WT) C57BL/6 mice and CHIP knock-in (KI) mice with a C57BL/6 background and CHIP overexpression in neural tissue underwent middle cerebral artery occlusion (MCAO) surgery to simulate CIR onset. Our data indicated that CHIP expression in the peri-infarct tissue was markedly increased after MCAO surgery. Compared with WT mice, CHIP KI mice significantly improved neurological deficit scores, decreased cerebral infarct volume, and attenuated brain edema and neuronal damage. Meanwhile, CHIP overexpression attenuated necroptosis and inflammation induced by MCAO surgery. These findings indicated that overexpression of CHIP might exert neuroprotective effects by attenuating necroptosis and inflammation during CIR injury, and increasing CHIP levels may be a potential strategy in cerebrovascular disease therapy.

E3 ligase activity of Carboxyl terminus of Hsc70 interacting protein (CHIP) in Wharton's jelly derived mesenchymal stem cells improves their persistence under hyperglycemic stress and promotes the prophylactic effects against diabetic cardiac damages

Recent studies indicate that umbilical cord stem cells are cytoprotective against several disorders. One critical limitation in using stem cells is reduction in their viability under stressful conditions, such as diabetes. However, the molecular intricacies responsible for diabetic conditions are not fully elucidated. In this study, we found that high glucose (HG) conditions induced loss of chaperone homeostasis, stabilized PTEN, triggered the downstream signaling cascade, and induced apoptosis and oxidative stress in Wharton's jelly derived mesenchymal stem cells (WJMSCs). Increased Carboxyl terminus of Hsc70 interacting protein (CHIP) expression promoted phosphatase and tensin homolog (PTEN) degradation via the ubiquitin-proteasome system and shortened its half-life during HG stress. Docking studies confirmed the interaction of CHIP with PTEN and FOXO3a with the Bim promoter region. Further, it was found that the chaperone system is involved in CHIP-mediated PTEN proteasomal degradation. CHIP depletion stabilizes PTEN whereas PTEN inhibition showed an inverse effect. CHIP overactivation suppressed the binding of FOXO3a with bim. Coculturing CHIP overexpressed WJMSCs suppressed HG-induced apoptosis and oxidative stress in embryo derived cardiac cell lines. CHIP overexpressing and PTEN silenced WJMSCs ameliorated diabetic effects in streptozotocin (STZ) induced diabetic rats and further improved their body weight and heart weight, and rescued from hyperglycemia-induced cardiac injury. Considering these, the current study suggests that CHIP confers resistance to apoptosis and acts as a potentiation factor in WJMSCs to provide protection from degenerative effects of diabetes.

Chaperone-assisted E3 ligase CHIP: A double agent in cancer

The carboxy-terminus of Hsp70-interacting protein (CHIP) is a ubiquitin ligase and co-chaperone belonging to Ubox family that plays a crucial role in the maintenance of cellular homeostasis by switching the equilibrium of the folding-refolding mechanism towards the proteasomal or lysosomal degradation pathway. It links molecular chaperones viz. HSC70, HSP70 and HSP90 with ubiquitin proteasome system (UPS), acting as a quality control system. CHIP contains charged domain in between N-terminal tetratricopeptide repeat (TPR) and C-terminal Ubox domain. TPR domain interacts with the aberrant client proteins via chaperones while Ubox domain facilitates the ubiquitin transfer to the client proteins for ubiquitination. Thus, CHIP is a classic molecule that executes ubiquitination for degradation of client proteins. Further, CHIP has been found to be indulged in cellular differentiation, proliferation, metastasis and tumorigenesis. Additionally, CHIP can play its dual role as a tumor suppressor as well as an oncogene in numerous malignancies, thus acting as a double agent. Here, in this review, we have reported almost all substrates of CHIP established till date and classified them according to the hallmarks of cancer. In addition, we discussed about its architectural alignment, tissue specific expression, sub-cellular localization, folding-refolding mechanisms of client proteins, E4 ligase activity, normal physiological roles, as well as involvement in various diseases and tumor biology. Further, we aim to discuss its importance in HSP90 inhibitors mediated cancer therapy. Thus, this report concludes that CHIP may be a promising and worthy drug target towards pharmaceutical industry for drug development.

CHIP-overexpressing Wharton's jelly-derived mesenchymal stem cells attenuate hyperglycemia-induced oxidative stress-mediated kidney injuries in diabetic rats

Accumulating studies have demonstrated the protective roles of mesenchymal stem cells against several disorders. However, one of their crucial limitations is reduced viability under stress conditions, including the hyperglycemia induced by diabetes. The molecular mechanisms involved in diabetes-induced kidney injuries are not fully elucidated. In this study, we found that high glucose (HG) reduced human proximal tubular epithelial cell viability. Further, hyperglycemia induced oxidative stress-mediated apoptosis and fibrosis in HK-2 cells via activation of the mitogen-activated protein kinases (MAPKs) including c-Jun N-terminal kinase JNK and p38 kinase. Carboxyl terminus of HSP70 interacting protein (CHIP) overactivation considerably rescued cell viability under HG stress. Moreover, Western blot analysis, flow cytometry, and MitoSOX staining revealed that hyperglycemia-induced mitochondrial oxidative stress production and apoptosis were attenuated in CHIP-overexpressing Wharton's jelly-derived mesenchymal stem cells (WJMSCs). Co-culture with CHIP-expressing WJMSCs maintained HK-2 cell viability, and inhibited apoptosis and fibrosis by attenuating HG-induced ROS-mediated MAPK activation. CHIP-overexpressing WJMSCs also rescued the decreased kidney weight and hyperglycemia-induced kidney damage observed in streptozotocin-induced diabetic rats. Cumulatively, the current research findings demonstrate that CHIP suppresses hyperglycemia-induced oxidative stress and confers resistance to MAPK-induced apoptosis and fibrosis, and suggests that CHIP protects WJMSCs and the high quality WJMSCs have therapeutic effects against diabetes-induced kidney injuries.

8-Formylophiopogonanone B antagonizes doxorubicin-induced cardiotoxicity by suppressing heme oxygenase-1-dependent myocardial inflammation and fibrosis

Doxorubicin (DOX) is a widely used antitumor drug that causes severe cardiotoxicity in patients; no effective strategy yet exists to address this problem. We previously reported that 8-formylophiopogonanone B (8-FOB), a natural isoflavone in Ophiopogon japonicas, antagonizes paraquat-induced hepatotoxicity. Here, we explored the mechanisms underlying DOX-induced cardiotoxicity as well as whether 8-FOB can alleviate DOX-induced cardiotoxicity. Acute cardiotoxicity was established by injecting C57BL/6J mice with a single dose of DOX (20 mg/kg, intraperitoneal). To elucidate the mechanisms underlying DOX-induced cardiotoxicity, differentially expressed genes between hearts from DOX-treated and control mice were identified from the Gene Expression Omnibus (GEO) database via GEO2R. Using the Cytoscape software plugin cytoHubba, five hub genes associated with DOX-induced cardiotoxicity were identified: CD68, PTEN, SERPINE1, AIF1, and HMOX1. However, of these, only HMOX1 protein expression levels were significantly increased after DOX treatment. We also confirmed that HMOX1-dependent myocardial inflammation and fibrosis were closely associated with DOX-induced cardiotoxicity. More importantly, 8-FOB protected against DOX-cardiotoxicity by ameliorating cardiac injury and dysfunction, reducing cardiac fibrosis and inflammatory cytokine release, and inhibiting HMOX1 expression. In conclusion, our results suggest that inhibition of HMOX1-dependent myocardial inflammatory insults and fibrosis is essential for 8-FOB to ameliorate DOX-caused cardiotoxicity.

Mesenchymal Stem Cell-Derived Small Extracellular Vesicles Protect Cardiomyocytes from Doxorubicin-Induced Cardiomyopathy by Upregulating Survivin Expression via the miR-199a-3p-Akt-Sp1/p53 Signaling Pathway

Cardiotoxicity is associated with the long-term clinical application of doxorubicin (DOX) in cancer patients. Mesenchymal stem cell-derived small extracellular vesicles (MSC-sEVs) including exosomes have been suggested for the treatment of various diseases, including ischemic diseases. However, the effects and functional mechanism of MSC-sEVs in DOX-induced cardiomyopathy have not been clarified. Here, MSC-sEVs were isolated from murine embryonic mesenchymal progenitor cell (C3H/10T1/2) culture media, using ultrafiltration. H9c2 cardiac myoblast cells were pretreated with MSC-sEVs and then exposed to DOX. For in vivo studies, male C57BL/6 mice were administered MSC-sEVs intravenously, prior to a single dose of DOX (15 mg/kg, intraperitoneal). The mice were sacrificed 14 days after DOX treatment. The results showed that MSC-sEVs protected cardiomyocytes from DOX-induced cell death. H9c2 cells treated with DOX showed downregulation of both phosphorylated Akt and survivin, whereas the treatment of MSC-sEVs recovered expression, indicating their anti-apoptotic effects. Three microRNAs (miRNAs) (miR 199a-3p, miR 424-5p, and miR 21-5p) in MSC-sEVs regulated the Akt-Sp1/p53 signaling pathway in cardiomyocytes. Among them, miR 199a-3p was involved in regulating survivin expression, which correlated with the anti-apoptotic effects of MSC-sEVs. In in vivo studies, the echocardiographic results showed that the group treated with MSC-sEVs recovered from DOX-induced cardiomyopathy, showing improvement of both the left ventricle fraction and ejection fraction. MSC-sEVs treatment also increased both survivin and B-cell lymphoma 2 expression in heart tissue compared to the DOX group. Our results demonstrate that MSC-sEVs have protective effects against DOX-induced cardiomyopathy by upregulating survivin expression, which is mediated by the regulation of Akt activation by miRNAs in MSC-sEVs. Thus, MSC-sEVs may be a novel therapy for the prevention of DOX-induced cardiomyopathy.

Improving anti-tumour efficacy of PEGylated liposomal doxorubicin by dual targeting of tumour cells and tumour endothelial cells using anti-p32 CGKRK peptide

The aim of this study was to surface-functionalize PEGylated liposomal doxorubicin (PLD) using anti-p32 CGKRK peptide to evaluate its anti-angiogenic and anti-tumour activities. CGKRK was conjugated to DSPE-mPEG₂₀₀₀-maleimide and post-inserted into PLD at 25, 50, 100, 200 and 400 peptides per each liposome and characterised for their size, zeta potential, drug loading, release properties; and cell binding, cell uptake and cytotoxicity on three C26, 4T1 and human umbilical vein endothelial cell (HUVEC) cell lines. The in vitro results indicated the better efficiency of the PLD-100 (PLD with 100 CGKRK) formulation on 4T1 and HUVEC cell lines. The results of anti-tube formation and spheroid assay indicated the efficiencies of the PLD-100 formulation compared with Caelyx^® in vitro. The in vivo studies indicated the higher tumour accumulation of PLD-100 formulation in comparison with Caelyx^® which also implied the higher survival rates in mice treated with PLD-100 formulation. Histological evaluations demonstrated that PLD-100 had no side-effects on major organs. In conclusion, the results of this study indicated that PLD-CGKRK- could efficiently target endothelial and tumour parenchymal cells which enhance the therapeutic efficacy of PLD and merits further investigation.

Fenofibrate attenuates doxorubicin-induced cardiac dysfunction in mice via activating the eNOS/EPC pathway

Endothelial progenitor cells (EPCs) improve endothelial impairment, which in turn restores endothelial function in patients with heart failure (HF). In the present study, we tested whether fenofibrate, with its anti-inflammatory and vasoprotective effects, could improve myocardial function by activating EPCs through the eNOS pathway in a doxorubicin (DOX)-induced cardiomyopathy mouse model. Wild-type mice were divided into 4 groups and treated with vehicle, DOX + saline, DOX + fenofibrate, and DOX + fenofibrate + L-NAME (N(ω)-nitro-L-arginine methyl ester). DOX-induced cardiac atrophy, myocardial dysfunction, the number of circulating EPCs and tissue inflammation were analyzed. Mice in the DOX + fenofibrate group had more circulating EPCs than those in the DOX + saline group (2% versus 0.5% of total events, respectively) after 4 weeks of treatment with fenofibrate. In addition, the inhibition of eNOS by L-NAME in vivo further abolished the fenofibrate-induced suppression of DOX-induced cardiotoxic effects. Protein assays revealed that, after DOX treatment, the differential expression of MMP-2 (matrix metalloproteinase-2), MMP-9 (matrix metalloproteinase-9), TNF-α (tumor necrosis factor-α), and NT-pro-BNP (N-terminal pro-B-type natriuretic peptide) between saline- and DOX-treated mice was involved in the progression of HF. Mechanistically, fenofibrate promotes Akt/eNOS and VEGF (vascular endothelial growth factor), which results in the activation of EPC pathways, thereby ameliorating DOX-induced cardiac toxicity.

Sodium nitrate co-supplementation does not exacerbate low dose metronomic doxorubicin-induced cachexia in healthy mice

The purpose of this study was to determine whether (1) sodium nitrate (SN) treatment progressed or alleviated doxorubicin (DOX)-induced cachexia and muscle wasting; and (2) if a more-clinically relevant low-dose metronomic (LDM) DOX treatment regimen compared to the high dosage bolus commonly used in animal research, was sufficient to induce cachexia in mice. Six-week old male Balb/C mice (n = 16) were treated with three intraperitoneal injections of either vehicle (0.9% NaCl; VEH) or DOX (4 mg/kg) over one week. To test the hypothesis that sodium nitrate treatment could protect against DOX-induced symptomology, a group of mice (n = 8) were treated with 1 mM NaNO₃ in drinking water during DOX (4 mg/kg) treatment (DOX + SN). Body composition indices were assessed using echoMRI scanning, whilst physical and metabolic activity were assessed via indirect calorimetry, before and after the treatment regimen. Skeletal and cardiac muscles were excised to investigate histological and molecular parameters. LDM DOX treatment induced cachexia with significant impacts on both body and lean mass, and fatigue/malaise (i.e. it reduced voluntary wheel running and energy expenditure) that was associated with oxidative/nitrostative stress sufficient to induce the molecular cytotoxic stress regulator, nuclear factor erythroid-2-related factor 2 (NRF-2). SN co-treatment afforded no therapeutic potential, nor did it promote the wasting of lean tissue. Our data re-affirm a cardioprotective effect for SN against DOX-induced collagen deposition. In our mouse model, SN protected against LDM DOX-induced cardiac fibrosis but had no effect on cachexia at the conclusion of the regimen.

Come Together: Protein Assemblies, Aggregates and the Sarcostat at the Heart of Cardiac Myocyte Homeostasis

Homeostasis in vertebrate systems is contingent on normal cardiac function. This, in turn, depends on intricate protein-based cellular machinery, both for contractile function, as well as, durability of cardiac myocytes. The cardiac small heat shock protein (csHsp) chaperone system, highlighted by αB-crystallin (CRYAB), a small heat shock protein (sHsp) that forms ∼3–5% of total cardiac mass, plays critical roles in maintaining proteostatic function via formation of self-assembled multimeric chaperones. In this work, we review these ancient proteins, from the evolutionarily preserved role of homologs in protists, fungi and invertebrate systems, as well as, the role of sHsps and chaperones in maintaining cardiac myocyte structure and function. We propose the concept of the “sarcostat” as a protein quality control mechanism in the sarcomere. The roles of the proteasomal and lysosomal proteostatic network, as well as, the roles of the aggresome, self-assembling protein complexes and protein aggregation are discussed in the context of cardiac myocyte homeostasis. Finally, we will review the potential for targeting the csHsp system as a novel therapeutic approach to prevent and treat cardiomyopathy and heart failure.

Egr-1 functions as a master switch regulator of remote ischemic preconditioning-induced cardioprotection

Despite improved treatment options myocardial infarction (MI) is still a leading cause of mortality and morbidity worldwide. Remote ischemic preconditioning (RIPC) is a mechanistic process that reduces myocardial infarction size and protects against ischemia reperfusion (I/R) injury. The zinc finger transcription factor early growth response-1 (Egr-1) is integral to the biological response to I/R, as its upregulation mediates the increased expression of inflammatory and prothrombotic processes. We aimed to determine the association and/or role of Egr-1 expression with the molecular mechanisms controlling the cardioprotective effects of RIPC. This study used H9C2 cells in vitro and a rat model of cardiac ischemia reperfusion (I/R) injury. We silenced Egr-1 with DNAzyme (ED5) in vitro and in vivo, before three cycles of RIPC consisting of alternating 5 min hypoxia and normoxia in cells or hind-limb ligation and release in the rat, followed by hypoxic challenge in vitro and I/R injury in vivo. Post-procedure, ED5 administration led to a significant increase in infarct size compared to controls (65.90 ± 2.38% vs. 41.00 ± 2.83%, p < 0.0001) following administration prior to RIPC in vivo, concurrent with decreased plasma IL-6 levels (118.30 ± 4.30 pg/ml vs. 130.50 ± 1.29 pg/ml, p < 0.05), downregulation of the cardioprotective JAK-STAT pathway, and elevated myocardial endothelial dysfunction. In vitro, ED5 administration abrogated IL-6 mRNA expression in H9C2 cells subjected to RIPC (0.95 ± 0.20 vs. 6.08 ± 1.40-fold relative to the control group, p < 0.05), resulting in increase in apoptosis (4.76 ± 0.70% vs. 2.23 ± 0.34%, p < 0.05) and loss of mitochondrial membrane potential (0.57 ± 0.11% vs. 1.0 ± 0.14%-fold relative to control, p < 0.05) in recipient cells receiving preconditioned media from the DNAzyme treated donor cells. This study suggests that Egr-1 functions as a master regulator of remote preconditioning inducing a protective effect against myocardial I/R injury through IL-6-dependent JAK-STAT signaling.

Discovery of Inhibitors of Aurora/PLK Targets as Anticancer Agents

Aurora and polo-like kinases control the G2/M phase in cell mitosis, which are both considered as crucial targets for cancer cell proliferations. Here, naphthalene-based Aurora/PLK coinhibitors as leading compounds were designed through in silico approach, and a total of 36 derivatives were synthesized. One candidate (AAPK-25) was selected under in vitro cell based high throughput screening with an IC50 value = 0.4 μM to human colon cancer cell HCT-116. A kinome scan assay showed that AAPK-25 was remarkably selective to both Aurora and PLK families. The relevant genome pathways were also depicted by microarray based gene expression analysis. Furthermore, validated from a set of in vitro and in vivo studies, AAPK-25 significantly inhibited the development of the colon cancer growth and prolonged the median survival time at the end of the administration (p < 0.05). To sum up, AAPK-25 has a great potential to be developed for a chemotherapeutic agent in clinical use.

Ethanol exposure in prenatal and early postnatal induced cardiac injury in rats: involvement of oxidative stress, Hsp70, ERK 1/2, JNK, and apoptosis in a 3-month follow-up study

Alcohol exposure during pregnancy induces a wide range of structural and functional abnormalities in the fetal heart. However, the underlying mechanism of this phenomenon is not well known. This study was undertaken to elucidate probable mechanisms of myocardial damage induced by prenatal and early postnatal ethanol treatment. Pregnant Wistar rats received ethanol 4.5 g/kg BW once per day from the seventh day of gestation (GD7) throughout lactation. The oxidative stress injury of the myocardium in pups was evaluated by measuring levels of oxidative stress biomarkers. Histopathological examinations and Western blot were performed to evaluate histological features, apoptosis, and molecular alterations in the myocardial tissue of male pups on the postnatal day 21 (PN-21) and postnatal day 90 (PN-90). The results showed that maternal ethanol consumption caused oxidative stress (impaired total antioxidant capacity and malondialdehyde), histological changes, and apoptosis of the myocardium in the pups on PN-21 and PN-90. At the molecular levels, Western blot analysis revealed that ethanol modulated the protein expression of p-ERK1/2, p-JNK, and Hsp70 in the myocardial tissue of the pups after 21 and 90 days of birth compared with the controls. These findings revealed that maternal ethanol intake induced cardiac toxicity in part, mediated by oxidative stress and apoptosis in the pups. A further mechanism study revealed that ethanol enhanced ERK1/2 and JNK phosphorylation and Hsp70 protein expression.

Extracorporeal shock waves protect cardiomyocytes from doxorubicin-induced cardiomyopathy by upregulating survivin via the integrin-ILK-Akt-Sp1/p53 axis

Doxorubicin (DOX) is a widely used anti-cancer drug; however, it has limited application due to cardiotoxicity. Extracorporeal shock waves (ESW) have been suggested to treat inflammatory and ischemic diseases, but the concrete effect of ESW in DOX-induced cardiomyopathy remain obscure. After H9c2 cells were subjected to ESW (0.04 mJ/cm²), they were treated with 1 μM DOX. As a result, ESW protected cardiomyocytes from DOX-induced cell death. H9c2 cells treated with DOX downregulated p-Akt and survivin expression, whereas the ESW treatment recovered both, suggesting its anti-apoptotic effect. ESW activated integrin α_vβ₃ and α_vβ₅, cardiomyocyte mechanosensors, followed by upregulation of ILK, p-Akt and survivin levels. Further, Sp1 and p53 were determined as key transcriptional factors mediating survivin expression via Akt phosphorylation by ESW. In in vivo acute DOX-induced cardiomyopathy model, the echocardiographic results showed that group subjected to ESW recovered from acute DOX-induced cardiomyopathy; left ventricular function was improved. The immunohistochemical staining results showed increased survivin and Bcl2 expression in ESW + DOX group compared to those in the DOX-injected group. In conclusion, non-invasive shockwaves protect cardiomyocytes from DOX-induced cardiomyopathy by upregulating survivin via integrin-ILK-Akt-Sp1/p53 pathway. In vivo study proposed ESW as a new kind of specific and safe therapy against acute DOX-induced cardiomyopathy.

Ursolic acid prevents doxorubicin-induced cardiac toxicity in mice through eNOS activation and inhibition of eNOS uncoupling

In addition to the known antitumour effects of ursolic acid (UA), increasing evidence indicates that this molecule plays a role in cardiac protection. In this study, the effects of ursolic acid on the heart in mice treated with doxorubicin (DOX) were assessed. The results showed that ursolic acid improved left ventrical fractional shortening (LVFS) and left ventrical ejection fraction (LVEF) of the heart, increased nitrogen oxide (NO) levels, inhibited reactive oxygen species (ROS) production and decreased cardiac apoptosis in mice treated with doxorubicin. Mechanistically, ursolic acid increased AKT and endothelial nitric-oxide synthase (eNOS) phosphorylation levels, and enhanced eNOS expression, while inhibiting doxorubicin induced eNOS uncoupling through NADPH oxidase 4 (NOX4) down-regulation. These effects of ursolic acid resulted in heart protection from doxorubicin-induced injury. Therefore, ursolic acid may be considered a potential therapeutic agent for doxorubicin-associated cardiac toxicity in clinical practice.

Multifaceted C-terminus of HSP70-interacting protein regulates tumorigenesis via protein quality control

C-terminus of heat shock protein 70 (HSP70)-interacting protein (CHIP) is an E3 ligase involved in a variety of protein homeostasis events implicated in diverse signaling pathways. Its involvement in varied and even opposite signaling circuits might be due to its hallmark signature of associating with molecular chaperones, including HSP90 and HSP70. Together, these proteins may be pivotal in implementing protein quality control. A curious and puzzling aspect of the function of CHIP is its capability to induce protein degradation via the proteasome- or lysosome-dependent pathways. In addition, these pathways are combined with ubiquitin-dependent or -independent pathways. This review focuses on the role of CHIP in the development or suppression of tumorigenesis. CHIP can act as a tumor suppressor by downregulating various oncogenes. CHIP also displays an oncogenic feature involving the inhibition of diverse tumor suppressors, including proteins related to intrinsic and extrinsic apoptotic pathways. The ability of CHIP to exhibit dual roles in determining the fate of cells has not been studied analytically. However, its association with various proteins involved in protein quality control might play a major role. In this review, the mechanistic roles of CHIP in tumor formation based on the regulation of diverse proteins are discussed.

Interleukin-12p35 Knock Out Aggravates Doxorubicin-Induced Cardiac Injury and Dysfunction by Aggravating the Inflammatory Response, Oxidative Stress, Apoptosis and Autophagy in Mice

Background

Recent evidence has demonstrated that interleukin 12p35 knockout (IL-12p35 KO) is involved in cardiac diseases by regulating the inflammatory response. The involvement of inflammatory cells has also been observed in doxorubicin (DOX)-induced cardiac injury. This study aimed to investigate whether IL-12p35 KO affects DOX-induced cardiac injury and the underlying mechanisms.

Methods

First, the effect of DOX treatment on cardiac IL-12p35 expression was assessed. In addition, to investigate the effect of IL-12p35 KO on DOX-induced cardiac injury, IL-12p35 KO mice were treated with DOX. Because IL-12p35 is the mutual subunit of IL-12 and IL-35, to determine the cytokine that mediates the effect of IL-12p35 KO on DOX-induced cardiac injury, mice were given phosphate-buffered saline (PBS), mouse recombinant IL-12 (rIL-12) or rIL-35 before treatment with DOX.

Results

DOX treatment significantly increased the level of cardiac IL-12p35 expression. In addition, IL-12p35 KO mice exhibited higher serum and heart lactate dehydrogenase levels, higher serum and heart creatine kinase myocardial bound levels, and greater cardiac dysfunction than DOX-treated mice. Furthermore, IL-12p35 KO further increased M1 macrophage and decreased M2 macrophage differentiation, aggravated the imbalance of oxidants and antioxidants, and further activated the mitochondrial apoptotic pathway and endoplasmic reticulum stress autophagy pathway. Both rIL-12 and rIL-35 protected against DOX-induced cardiac injury by alleviating the inflammatory response, oxidative stress, apoptosis and autophagy.

Conclusions

IL-12p35 KO aggravated DOX-induced cardiac injury by amplifying the levels of inflammation, oxidative stress, apoptosis and autophagy. (234 words).

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IL-12p35 KO aggravates DOX-induced cardiac injury and dysfunction.

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IL-12p35 further increases the DOX-induced imbalance in inflammation, oxidative stress, apoptosis and autophagy.

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Both exogenous rIL-12 and rIL-35 relieved cardiac injury mediated by DOX.

CD4+ T helper (Th) cells are closely related to cardiac injury; regulatory T cells (Tregs) are a new subset of Th cells, and IL-35 is the functional cytokine of Tregs. Cardiac injury mediated by DOX is the most serious complication during chemotherapy, and there are no good preventive measures. This study aimed to investigate whether IL-35 can reduce cardiac injury induced by DOX during chemotherapy. In addition to IL-35, IL-12p35 KO can cancel the biological effect of IL-12; therefore, we also determined whether IL-12 participates in DOX-induced cardiac injury and the underlying mechanisms.

Cardiomyocyte-specific disruption of Cathepsin K protects against doxorubicin-induced cardiotoxicity

The lysosomal cysteine protease Cathepsin K is elevated in humans and animal models of heart failure. Our recent studies show that whole-body deletion of Cathepsin K protects mice against cardiac dysfunction. Whether this is attributable to a direct effect on cardiomyocytes or is a consequence of the global metabolic alterations associated with Cathepsin K deletion is unknown. To determine the role of Cathepsin K in cardiomyocytes, we developed a cardiomyocyte-specific Cathepsin K-deficient mouse model and tested the hypothesis that ablation of Cathepsin K in cardiomyocytes would ameliorate the cardiotoxic side-effects of the anticancer drug doxorubicin. We used an α-myosin heavy chain promoter to drive expression of Cre, which resulted in over 80% reduction in protein and mRNA levels of cardiac Cathepsin K at baseline. Four-month-old control (Myh-Cre^-; Ctsk^fl/fl) and Cathepsin K knockout (Myh-Cre⁺; Ctsk^fl/fl) mice received intraperitoneal injections of doxorubicin or vehicle, 1 week following which, body and tissue weight, echocardiographic properties, cardiomyocyte contractile function and Ca²⁺-handling were evaluated. Control mice treated with doxorubicin exhibited a marked increase in cardiac Cathepsin K, which was associated with an impairment in cardiac structure and function, evidenced as an increase in end-systolic and end-diastolic diameters, decreased fractional shortening and wall thickness, disruption in cardiac sarcomere and microfilaments and impaired intracellular Ca²⁺ homeostasis. In contrast, the aforementioned cardiotoxic effects of doxorubicin were attenuated or reversed in mice lacking cardiac Cathepsin K. Mechanistically, Cathepsin K-deficiency reconciled the disturbance in cardiac energy homeostasis and attenuated NF-κB signaling and apoptosis to ameliorate doxorubicin-induced cardiotoxicity. Cathepsin K may represent a viable drug target to treat cardiac disease.

Vitamin D attenuates pressure overload-induced cardiac remodeling and dysfunction in mice

Vitamin D (VD) and its analogues play critical roles in metabolic and cardiovascular diseases. Recent studies have demonstrated that VD exerts a protective role in cardiovascular diseases. However, the beneficial effect of VD on pressure overload-induced cardiac remodeling and dysfunction and its underlying mechanisms are not fully elucidated. In this study, cardiac dysfunction and hypertrophic remodeling in mice were induced by pressure overload. Cardiac function was evaluated by echocardiography, and myocardial histology was detected by H&E and Masson's trichrome staining. Cardiomyocyte size was detected by wheat germ agglutinin staining. The protein levels of signaling mediators were examined by western blotting while mRNA expression of hypertrophic and fibrotic markers was examined by qPCR analysis. Oxidative stress was detected by dihydroethidine staining. Our results showed that administration of VD3 significantly ameliorates pressure overload-induced contractile dysfunction, cardiac hypertrophy, fibrosis and inflammation in mice. In addition, VD3 treatment also markedly inhibited cardiac oxidative stress and apoptosis. Moreover, protein levels of calcineurin A, ERK1/2, AKT, TGF-β, GRP78, cATF6, and CHOP were significantly reduced whereas SERCA2 level was upregulated in the VD3-treated hearts compared with control. These results suggest that VD3 attenuates cardiac remodeling and dysfunction induced by pressure overload, and this protective effect is associated with inhibition of multiple signaling pathways.

Angiotensin-converting enzyme 2 overexpression protects against doxorubicin-induced cardiomyopathy by multiple mechanisms in rats

Angiotensin-converting enzyme 2 (ACE2) is considered a potential therapeutic target of the renin-angiotensin system (RAS) for the treatment of cardiovascular diseases. We aimed to explore the effects of ACE2 overexpression on doxorubicin-induced cardiomyopathy in rats. Rats were randomly divided into treatment and control groups. The rats of treatment group were injected intraperitoneally with 6 doses of doxorubicin (2.5 mg/kg) within a period of two weeks. Two weeks after the initial injection of doxorubicin, these rats were randomly divided into Mock, Ad-EGFP, Ad-ACE2, and Cilazapril groups. The rats of Ad-EGFP and Ad-ACE2 groups received intramyocardial injection of Ad-EGFP and Ad-ACE2, respectively. The rats of Cilazapril group received cilazapril (10 mg/kg/day) via intragastric intubation. Apoptosis, inflammation, oxidative stress, cardiac function, the extent of myocardial fibrosis, and levels of ACE2, ACE, angiotensin II (AngII), and angiotensin (1–7) were evaluated. Four weeks after ACE2 gene transfer, the Ad-ACE2 group showed not only reduced apoptosis, inflammatory response, oxidative stress, left ventricular (LV) volume, extent of myocardial fibrosis and mortality of rats, but also increased LV ejection fraction and ACE2 expression level compared with the Mock and Ad-EGFP groups. ACE2 overexpression was superior to cilazapril in improving doxorubicin-induced cardiomyopathy. The putative mechanisms may involve activation of the AMPK and PI3K-AKT pathways, inhibition of the ERK pathway, decrease of TGF-β1 expression, and interactions of shifting RAS components, such as decreased myocardium AngII levels, increased myocardium Ang (1–7) levels, and reduced ACE expression. Thus, ACE2 may be a novel therapeutic approach to prevent and treat doxorubicin-induced cardiomyopathy.

Inhibition of TRPA1 Attenuates Doxorubicin-Induced Acute Cardiotoxicity by Suppressing Oxidative Stress, the Inflammatory Response, and Endoplasmic Reticulum Stress

The transient receptor potential ankyrin 1 (TRPA1) channel is expressed in cardiomyocytes and involved in many cardiovascular diseases. However, the expression and function of TRPA1 in doxorubicin- (Dox-) induced acute cardiotoxicity have not been elucidated. This study aimed at investigating whether blocking the TRPA1 channel with the specific inhibitor HC-030031 (HC) attenuates Dox-induced cardiac injury. The animals were randomly divided into four groups: control, HC, Dox, and Dox + HC. Echocardiography was used to evaluate cardiac function, and the heart was removed for molecular experiments. The results showed that the expression of TRPA1 was increased in the heart after Dox treatment. Cardiac dysfunction and increased serum CK-MB and LDH levels were induced by Dox, but these effects were attenuated by HC treatment. In addition, HC mitigated Dox-induced oxidative stress, as evidenced by the decreased MDA level and increased GSH level and SOD activity in the Dox + HC group. Meanwhile, HC treatment lowered the levels of the proinflammatory cytokines IL-1β, IL-6, IL-17, and TNF-α induced by Dox. Furthermore, HC treatment mitigated endoplasmic reticulum (ER) stress and cardiomyocyte apoptosis induced by Dox. These results indicated that inhibition of TRPA1 could prevent Dox-induced cardiomyocyte apoptosis in mice by inhibiting oxidative stress, inflammation, and ER stress.

Signalling mechanisms underlying doxorubicin and Nox2 NADPH oxidase-induced cardiomyopathy: involvement of mitofusin-2

BACKGROUND AND PURPOSE

The anthracycline doxorubicin (DOX), although successful as a first-line cancer treatment, induces cardiotoxicity linked with increased production of myocardial ROS, with Nox2 NADPH oxidase-derived superoxide reported to play a key role. The aim of this study was to identify novel mechanisms underlying development of cardiac remodelling/dysfunction further to DOX-stimulated Nox2 activation.

EXPERIMENTAL APPROACH

Nox2-/- and wild-type (WT) littermate mice were administered DOX (12 mg·kg-1 over 3 weeks) prior to study at 4 weeks. Detailed mechanisms were investigated in murine HL-1 cardiomyocytes, employing a robust model of oxidative stress, gene silencing and pharmacological tools.

KEY RESULTS

DOX-induced cardiac dysfunction, cardiomyocyte remodelling, superoxide production and apoptosis in WT mice were attenuated in Nox2-/- mice. Transcriptional analysis of left ventricular tissue identified 152 differentially regulated genes (using adjusted P < 0.1) in DOX-treated Nox2-/- versus WT mice, and network analysis highlighted 'Cell death and survival' as the biological function most significant to the dataset. The mitochondrial membrane protein, mitofusin-2 (Mfn2), appeared as a strong candidate, with increased expression (1.5-fold), confirmed by qPCR (1.3-fold), matching clear published evidence of promotion of cardiomyocyte cell death. In HL-1 cardiomyocytes, targeted siRNA knockdown of Nox2 decreased Mfn2 protein expression, but not vice versa. While inhibition of Nox2 activity along with DOX treatment attenuated its apoptotic and cytotoxic effects, reduced apoptosis after Mfn2 silencing reflected a sustained cytotoxic response and reduced cell viability.

CONCLUSIONS AND IMPLICATIONS

DOX-induced and Nox2-mediated up-regulation of Mfn2, rather than contributing to cardiomyocyte dysfunction through apoptotic pathways, appears to promote a protective mechanism.

LINKED ARTICLES

This article is part of a themed section on New Insights into Cardiotoxicity Caused by Chemotherapeutic Agents. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.21/issuetoc.

Oral administration of Ginsenoside Rg1 prevents cardiac toxicity induced by doxorubicin in mice through anti-apoptosis

Although Ginsenoside Rg1 has been reported to have protective cardiac effects, its effects on cardiac toxicity induced by doxorubicin needs to be studied. The present study investigated the effects of oral administration of Rg1 on the heart in mice treated with doxorubicin and found improved fractional shortening and ejection fraction of the heart and decreased cardiac apoptosis in mice treated with doxorubicin. The underlying mechanisms include increased phosphorylation of Akt and Erk by Rg1, increased ratio of Bcl-2 and Bax, and decreased release of cytochrome c from mitochondria, thereby protecting the heart from doxorubicin-induced apoptosis. This phenotype suggested that the oral administration of Rg1 may be a potential method preventing the cardiac toxicity caused by doxorubicin in clinical practice.

Mechanistic clues to the protective effect of chrysin against doxorubicin-induced cardiomyopathy: Plausible roles of p53, MAPK and AKT pathways

Doxorubicin (DOX) is the mainstay chemotherapeutic agent against a variety of human neoplasmas. However, its clinical utility is limited by its marked cardiotoxicity. Chrysin, is a natural flavone which possesses antioxidant, anti-inflammatory and anti-cancer properties. The current study aimed to investigate the potential protective effect of chrysin against DOX-induced chronic cardiotoxicity and the underlying molecular mechanisms. Male Sprague-Dawley rats were treated with either DOX (5 mg/kg, once a week) and/or chrysin (50 mg/kg, four times a week) for four weeks. Chrysin prevented DOX-induced cardiomyopathy which was evident by conduction abnormalities, elevated serum CKMB and LDH and histopathological changes. Chrysin also ameliorated DOX-induced oxidative stress by decreasing lipid peroxidation and upregulating the antioxidant enzymes. Moreover, chrysin attenuated DOX-induced apoptosis via decreasing expression of p53, Bax, Puma, Noxa, cytochrome c and caspase-3 while increasing expression of Bcl-2. DOX induced activation of MAPK; p38 and JNK and increased expression of NF-κB. Meanwhile, DOX suppressed AKT pathway via decreasing expression of its upstream activator VEGF and increasing expression of PTEN. Conversely, chrysin effectively neutralised all these effects. Collectively, these findings indicate that chrysin effectively protected against DOX-induced cardiomyopathy via suppressing oxidative stress, p53-dependent apoptotic pathway, MAPK and NF-κB pathways while augmenting the VEGF/AKT pathway.

The carboxyl terminus of heat shock protein 70-interacting protein (CHIP) participates in high glucose-induced cardiac injury

The carboxyl terminus of heat shock protein 70-interacting protein (CHIP) is confirmed to have a protective effect on the myocardium, but its effect on diabetic cardiomyopathy is unclear. Small interfering RNA (siRNA) was used for knockdown experiments in neonatal rat cardiomyocytes to examine the function of CHIP in high glucose-induced injury. High glucose stimulated the production of reactive oxygen species (ROS), nicotinamide adenine dinucleotide phosphate oxidase (NOX), interleukin-1β (IL-1β), interleukin-6 (IL-6), and monocyte chemoattractant protein-1 (MCP-1) production. However, cardiomyocytes lacking CHIP suffered from increased oxidative stress and inflammatory responses. High glucose increased the expression of Bax and caspase-3 mRNAs, decreased the expression of Bcl-2 mRNA, and up-regulated the expression of the nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) proteins. However, upon CHIP knockdown, the expression of Bax and caspase-3 mRNAs increased even further, and the expression of Bcl-2 mRNA was further suppressed. The expression of the phosphorylated p65 and p38 proteins (p-p65 and p-p38) was also further enhanced. Thus, CHIP is a potent cardioprotective molecule.

UVRAG Deficiency Exacerbates Doxorubicin-Induced Cardiotoxicity

Doxorubicin (DOX) is an effective chemotherapeutic drug in the treatment of various types of cancers. However, its clinical application has been largely limited by potential development of cardiotoxicity. Previously we have shown that ultra-violet radiation resistance-associated gene (UVRAG), an autophagy-related protein, is essential for the maintenance of autophagic flux in the heart under physiological conditions. Here, we sought to determine the role of UVRAG-mediated autophagy in DOX-induced cardiotoxicity. Mouse models of acute or chronic DOX-induced cardiotoxicity were established. UVRAG deficiency exacerbated DOX-induced mortality and cardiotoxicity manifested by increased cytoplasmic vacuolization, enhanced collagen accumulation, elevated serum activities of lactate dehydrogenase and myocardial muscle creatine kinase, higher ROS levels, aggravated apoptosis and more depressed cardiac function. Autophagic flux was impaired in DOX-induced cardiotoxicity. UVRAG deficiency aggravated impaired autophagic flux in DOX-induced cardiotoxicity. Intermittent fasting restored autophagy and ameliorated pathological alterations of DOX-induced cardiotoxicity. Collectively, our data suggest that UVRAG deficiency exacerbates DOX-induced cardiotoxicity, at least in part, through aggravation of DOX-induced impaired autophagic flux. Intermittent fasting, which restores blunted autophagic flux and ameliorates pathology in the mouse models of DOX-induced cardiotoxicity, may be used as a potential preventive or therapeutic approach for DOX cardiotoxicity.