Chitosan oligosaccharides prevent doxorubicin-induced oxidative stress and cardiac apoptosis through activating p38 and JNK MAPK mediated Nrf2/ARE pathway

Enhancing impact of dietary nano formulated quercetin on laying performance: egg quality, oxidative stability of stored eggs, intestinal immune and antioxidants related genes expression

BACKGROUND

Nutritional interventions with natural antioxidants can provide a pragmatic solution for modifying hens' performance and maintaining oxidative stability of eggs during storage. Quercetin is the most abundant flavonoids with potent antioxidant and immune stimulant activities. The concept of incorporating of quercetin, as potent antioxidant and immunostimulant, into effective nano-carriers (QNPs) has promoted their bioavailability and stability thus, their effectiveness for the first time were assessed on laying hens' performance and immunity, eggs quality during storage. Four hundred 12-weeks-old Hy-line brown laying hens were distributed to four experimental groups: control group fed basal diets, and other 3 groups fed basal diets fortified with 100, 200 and 300 mg/kg QNPs for 60 weeks.

RESULTS

Laying performance and quality of laid eggs were improved as expressed by elevated laying rate, egg mass %, eggs weight and yolk weight in QNPs200 and 300. Fortification of QNPs300 remarkably decreased layers serum total cholesterol concurrently with decreased egg yolk saturated fatty acids and cholesterol while increased polyunsaturated fatty acids. Over- 45 days storage period, QNPs enhanced phospholipids, total phenolics and flavonoids, total antioxidant activity (T-AOC) simultaneous with decreased MDA content in eggs. Furthermore, enhanced immune response was detected in both in serum and intestine of QNPs fed hens as reflected by higher lysozymes activity, IgM, IgG and phagocytic index and demotion of NO together with AvBD 6-12, IL-10, IgM and ATg 5-7-12 upregulation and downregulation of IL-1β and TNF-α especially at QNPs200 and 300. Intestinal redox balance was modified via decreasing H2O2 and MDA simultaneous with upregulation of catalase, SOD, GSH-Px, HO-1 and NQO1 in groups fed higher doses of QNPs.

CONCLUSIONS

QNPs supplementation provides a new nutritional strategy towards increasing hen performance, fortification of eggs with natural antioxidants that prevents egg quality deterioration during storage.

Targeted biocompatible Zn-metal-organic framework nanocomposites for intelligent chemotherapy of breast cancer cells

Finding a novel drug delivery system (DDS) represents one of the most challenging endeavors in cancer therapy. Hence, in this study, we developed a new biocompatible and biodegradable zinc-based nanoscale metal-organic framework (Zn-NMOF) coated with folic acid (FA) functionalized chitosan (CS) to facilitate targeted delivery of doxorubicin (D), a standard chemotherapeutic agent, into breast cancer cells. The synthesis of the NMOF-CS-FA-D nanocomposite preceded its comprehensive characterization via FT-IR, DLS, XRD, SEM, and TEM analyses. Subsequent in vitro studies were conducted on MCF-7 breast cancer cells and HFF-1 normal cells, encompassing assessments of cell viability, expression levels of apoptotic and autophagy genes, cell cycle arrest, and apoptotic analyses. The size of the NMOF-CS-FA-D particles was determined to be less than 80 nm, with a drug loading efficiency of 72 ± 5%. The release kinetics of DOX from the nanocomposite were investigated, revealing controlled release behavior at pH 7.4 and accelerated release at pH 5.0, which is conducive to drug delivery into cancer cells. In vitro results indicated a 17.39% ± 6.34 cell viability after 24 h of treatment with a 40 nM concentration of the NMOF-CS-FA-D nanocomposite. Furthermore, the expression levels of Caspase-9 and BAX, key apoptotic genes, along with BECLIN1, an autophagy gene, were found to increase by two-fold, four-fold, and two-fold, respectively, following 5 h of treatment with the nanocomposite. Additionally, analysis of cell cycle distribution revealed 15.4 ± 2% of cells in the sub-G1 phase, indicative of apoptotic cells, and 31.9% of cells undergoing early and late apoptosis in MCF-7 cells. Collectively, these findings underscore the potential of the NMOF-CS-FA-D nanocomposite in inhibiting cancer cell proliferation with low side effects.

Influence of Redox-Active Chitosan-Polyaminoxyl Micelles Loaded with Daunorubicin on Activity of Nrf2 Transcription Factor

A new system for delivery of anthracycline antibiotics based on chitosan-polyaminoxyls (CPA) was studied in a model of non-tumor (human embryonic mesenchymal stem cells) and tumor cells (human hepatocellular carcinoma) in vitro. The presence of CPA micelles considerably suppresses daunorubicin-induced ROS generation in normal cells without affecting this process in tumor cells. CPA micelles do not reduce the cytotoxic effect of daunorubicin and do not prevent its accumulation in cells. The use of CPA significantly increases accumulation of Nrf2 transcription factor in the nuclei of both normal and tumor cells in comparison with free daunorubicin. Increased nuclear translocation of Nrf2 leads to a significant increase in the expression of its target gene TXN1, but not the NQO1, GPX1, and HMOX1 genes, the increased expression of which can lead to the development of resistance to anthracycline antibiotics. Redox-active CPA micelles have great potential for the development of nanoparticles for the transport of anthracycline antibiotics in experimental tumor chemotherapy, and also as promising activators of Nrf2 transcription factor.

Programmed death of cardiomyocytes in cardiovascular disease and new therapeutic approaches

Cardiovascular diseases (CVDs) have a complex pathogenesis and pose a major threat to human health. Cardiomyocytes have a low regenerative capacity, and their death is a key factor in the morbidity and mortality of many CVDs. Cardiomyocyte death can be regulated by specific signaling pathways known as programmed cell death (PCD), including apoptosis, necroptosis, autophagy, pyroptosis, and ferroptosis, etc. Abnormalities in PCD can lead to the development of a variety of cardiovascular diseases, and there are also molecular-level interconnections between different PCD pathways under the same cardiovascular disease model. Currently, the link between programmed cell death in cardiomyocytes and cardiovascular disease is not fully understood. This review describes the molecular mechanisms of programmed death and the impact of cardiomyocyte death on cardiovascular disease development. Emphasis is placed on a summary of drugs and potential therapeutic approaches that can be used to treat cardiovascular disease by targeting and blocking programmed cell death in cardiomyocytes.

Comparison of the protective effects of chitosan oligosaccharides and chitin oligosaccharide on apoptosis, inflammation and oxidative stress

Chitin degradation products, especially chitosan oligosaccharides (COSs), are highly valued in various industrial fields, such as food, medicine, cosmetics and agriculture, for their rich resources and high cost-effectiveness. However, little is known about the impact of acetylation on COS cellular bioactivity. The present study aimed to compare the differential effects of COS and highly N-acetylated COS (NACOS), known as chitin oligosaccharide, on H2O2-induced cell stress. MTT assay showed that pretreatment with NACOS and COS markedly inhibited H2O2-induced RAW264.7 cell death in a concentration-dependent manner. Flow cytometry indicated that NACOS and COS exerted an anti-apoptosis effect on H2O2-induced oxidative damage in RAW264.7 cells. NACOS and COS treatment ameliorated H2O2-induced RAW264.7 cell cycle arrest. Western blotting revealed that the anti-oxidation effects of NACOS and COS were mediated by suppressing expression of proteins involved in H2O2-induced apoptosis, including Bax, Bcl-2 and cleaved PARP. Furthermore, the antagonist effects of NACOS were greater than those of COS, suggesting that acetylation was essential for the protective effects of COS.

Precision Treatment of Anthracycline-Induced Cardiotoxicity: An Updated Review

OPINION STATEMENT

Anthracycline (ANT)-induced cardiotoxicity (AIC) is a particularly prominent form of cancer therapy-related cardiovascular toxicity leading to the limitations of ANTs in clinical practice. Even though AIC has drawn particular attention, the best way to treat it is remaining unclear. Updates to AIC therapy have been made possible by recent developments in research on the underlying processes of AIC. We review the current molecular pathways leading to AIC: 1) oxidative stress (OS) including enzymatic-induced and other mechanisms; 2) topoisomerase; 3) inflammatory response; 4) cardiac progenitor cell damage; 5) epigenetic changes; 6) renin-angiotensin-aldosterone system (RAAS) dysregulation. And we systematically discuss current prevention and treatment strategies and novel pathogenesis-based therapies for AIC: 1) dose reduction and change; 2) altering drug delivery methods; 3) antioxidants, dexrezosen, statina, RAAS inhibitors, and hypoglycemic drugs; 4) miRNA, natural phytochemicals, mesenchymal stem cells, and cardiac progenitor cells. We also offer a fresh perspective on the management of AIC by outlining the current dilemmas and challenges associated with its prevention and treatment.

Role of Oxidative Stress and Inflammation in Doxorubicin-Induced Cardiotoxicity: A Brief Account

Cardiotoxicity is the main side effect of several chemotherapeutic drugs. Doxorubicin (Doxo) is one of the most used anthracyclines in the treatment of many tumors, but the development of acute and chronic cardiotoxicity limits its clinical usefulness. Different studies focused only on the effects of long-term Doxo administration, but recent data show that cardiomyocyte damage is an early event induced by Doxo after a single administration that can be followed by progressive functional decline, leading to overt heart failure. The knowledge of molecular mechanisms involved in the early stage of Doxo-induced cardiotoxicity is of paramount importance to treating and/or preventing it. This review aims to illustrate several mechanisms thought to underlie Doxo-induced cardiotoxicity, such as oxidative and nitrosative stress, inflammation, and mitochondrial dysfunction. Moreover, here we report data from both in vitro and in vivo studies indicating new therapeutic strategies to prevent Doxo-induced cardiotoxicity.

Dietary Chitosan Attenuates High-Fat Diet-Induced Oxidative Stress, Apoptosis, and Inflammation in Nile Tilapia (Oreochromis niloticus) through Regulation of Nrf2/Kaep1 and Bcl-2/Bax Pathways

Fatty liver injury is a prevalent condition in most farmed fish, yet the molecular mechanisms underpinning this pathology remain largely elusive. A comprehensive feeding trial spanning eight weeks was conducted to discern the potential of dietary chitosan in mitigating the deleterious effects of a high-fat diet (HFD) while concurrently exploring the underlying mechanism. Growth performance, haemato-biochemical capacity, antioxidant capacity, apoptotic/anti-apoptotic gene expression, inflammatory gene expression, and histopathological changes in the liver, kidney, and intestine were meticulously assessed in Nile tilapia. Six experimental diets were formulated with varying concentrations of chitosan. The first three groups were administered a diet comprising 6% fat with chitosan concentrations of 0%, 5%, and 10% and were designated as F6Ch0, F6Ch5, and F6Ch10, respectively. Conversely, the fourth, fifth, and sixth groups were fed a diet containing 12% fat with chitosan concentrations of 0%, 5%, and 10%, respectively, for 60 days and were termed F12Ch0, F12Ch5, and F12Ch10. The results showed that fish fed an HFD demonstrated enhanced growth rates and a significant accumulation of fat in the perivisceral tissue, accompanied by markedly elevated serum hepatic injury biomarkers and serum lipid levels, along with upregulation of pro-apoptotic and inflammatory markers. In stark contrast, the expression levels of nrf2, sod, gpx, and bcl-2 were notably decreased when compared with the control normal fat group. These observations were accompanied by marked diffuse hepatic steatosis, diffuse tubular damage, and shortened intestinal villi. Intriguingly, chitosan supplementation effectively mitigated the aforementioned findings and alleviated intestinal injury by upregulating the expression of tight junction-related genes. It could be concluded that dietary chitosan alleviates the adverse impacts of an HFD on the liver, kidney, and intestine by modulating the impaired antioxidant defense system, inflammation, and apoptosis through the variation in nrf2 and cox2 signaling pathways.

Fabrication of chitosan-based emulsion as an adjuvant to enhance nasal mucosal immune responses

Nasal vaccine is a non-invasive vaccine that activates systemic and mucosal immunity in the presence of an adjuvant, thereby enhancing immune function. In this work, chitosan/oligochitosan/tween 80 (CS-COS-T80) co-stabilized emulsion was designed and further used as the nasal adjuvant. CS-COS-T80 emulsion exhibited outstanding stability under pH 6-8 with uniformly dispersed droplets and nano-scale particle size (<0.25 μm), and maintained stable at 4 °C for 150-day storage. Addition of model antigen ovalbumin (OVA) had no effect on the stability of CS-COS-T80 emulsion. In vivo nasal immunity indicated that CS-COS-T80 emulsion prolonged the retention time of OVA in the nasal cavity (from 4 to 8 h to >12 h), as compared to T80-emulsion. CS-COS-T80 emulsion produced a stronger mucosal immune response to OVA, with secretory IgA levels 5-fold and 2-fold higher than those of bare OVA and commercial adjuvant MF59, respectively. Compared to MF59, CS-COS-T80 induced a stronger humoral immune response and a mixed Th1/Th2 immune response of OVA after immunization. Furthermore, in the presence of CS-COS-T80 emulsion, the secretion of IL-4 and IFN-γ and the activation of splenocyte memory T-cell differentiation increased from 173.98 to 210.21 pg/mL and from 75.46 to 104.01 pg/mL, respectively. Therefore, CS-COS-T80 emulsion may serve as a promising adjuvant platform.

Dietary supplementation with Neolamarckia cadamba leaf extract improves broiler meat quality by enhancing antioxidant capacity and regulating metabolites

This study was to evaluate the effect of supplementing the diet of broilers with Neolamarckia cadamba leaf extract (NCLE) on meat quality by evaluating antioxidant parameters and the expression of genes in the p38 mitogen-activated protein kinase/nuclear factor-erythroid 2-related factor 2/antioxidant responsive element (p38 MAPK/Nrf2/ARE) signaling pathway, coupled with LC-MS-based metabolomic analysis. A total of 480 one-day-old male broilers were randomly allocated to four treatment groups-a control (CON) group, which was fed a basal diet, and three NCLE treatment groups, which were fed the basal diet supplemented with 100, 200, or 400 mg/kg NCLE (N1, N2, and N3 groups, respectively) for 42 d. Compared with the CON group, meat quality was improved in the N2 and N3 groups, as evidenced by the higher pH45min (P < 0.05) and lower shear force (P < 0.05) in breast muscle (BM) and lower drip loss at 48 h (P < 0.05) in leg muscle (LM). Moreover, BM antioxidant capacity was significantly enhanced in the N3 group, characterized by an increase in the total antioxidant capacity (T-AOC), the concentrations of glutathione peroxidase (GSH-Px) and catalase (CAT), and the relative mRNA expression of p38 MAPK, extracellular-signal regulated kinase (ERK1/2), c-Jun N-terminal kinase (JNK), Nrf2, CAT, and GSH-Px (P < 0.05). Similarly, LM in the N3 group displayed higher T-AOC, increased GSH-Px and CAT concentrations, reduced malonaldehyde contents (P < 0.05), and upregulation of the relative mRNA levels of JNK, Nrf2, heme oxygenase, CAT, and superoxide dismutase (SOD) (P < 0.05). Metabolomics analysis revealed that D-arabinono-1,4-lactone and lyso-PAF C-16-d4 were negatively correlated with shear force and cooking loss (P < 0.05) and displayed increased abundance in BM of the N3 group. L-Serine levels were upregulated while D-fructose 1,6-diphosphate contents were downregulated in the three NCLE groups. Finally, the differential metabolites in both BM and LM were involved in amino acid metabolism pathways. Our results indicated that NCLE supplementation improved meat quality by enhancing antioxidant enzyme activities, promoting the expression of genes in the p38 MAPK/Nrf2/ARE signaling pathway, and regulating amino acid metabolism. The optimal NCLE concentration was found to be 400 mg/kg.

Wine- and stir-frying processing of Cuscutae Semen enhance its ability to alleviate oxidative stress and apoptosis via the Keap 1-Nrf2/HO-1 and PI3K/AKT pathways in H2O2-challenged KGN human granulosa cell line

BACKGROUND

Cuscutae Semen (CS) has been prescribed in traditional Chinese medicine (TCM) for millennia as an aging inhibitor, an anti-inflammatory agent, a pain reliever, and an aphrodisiac. Its three main forms include crude Cuscutae Semen (CCS), wine-processed CS (WCS), and stir-frying-processed CS (SFCS). Premature ovarian insufficiency (POI) is a globally occurring medical condition. The present work sought a highly efficacious multi-target therapeutic approach against POI with minimal side effects. Finally, it analyzed the relative differences among CCS, WCS and SFCS in terms of their therapeutic efficacy and modes of action against H2O2-challenged KGN human granulosa cell line.

METHODS

In this study, ultrahigh-performance liquid chromatography (UPLC)-Q-ExactiveTM Orbitrap-mass spectrometry (MS), oxidative stress indices, reactive oxygen species (ROS), Mitochondrial membrane potential (MMP), real-time PCR, Western blotting, and molecular docking were used to investigate the protective effect of CCS, WCS and SFCS on KGN cells oxidative stress and apoptosis mechanisms.

RESULTS

The results confirmed that pretreatment with CCS, WCS and SFCS reduced H2O2-induced oxidative damage, accompanied by declining ROS levels and malondialdehyde (MDA) accumulation in the KGN cells. CCS, WCS and SFCS upregulated the expression of antioxidative levels (GSH, GSH/GSSG ratio, SOD, T-AOC),mitochondrial membrane potential (MMP) and the relative mRNA(Nrf2, Keap1, NQO-1, HO-1, SOD-1, CAT). They inhibited apoptosis by upregulating Bcl-2, downregulating Bax, cleaved caspase-9, and cleaved caspase-3, and lowering the Bax/Bcl-2 ratio. They also exerted antioxidant efficacy by partially activating the PI3K/Akt and Keap1-Nrf2/HO-1 signaling pathways.

CONCLUSIONS

The results of the present work demonstrated the inhibitory efficacy of CCS, WCS and SFCS against H2O2-induced oxidative stress and apoptosis in KGN cells and showed that the associated mechanisms included Keap1-Nrf2/HO-1 activation, P-PI3K upregulation, and P-Akt-mediated PI3K-Akt pathway induction.

Resveratrol protects against doxorubicin-induced cardiotoxicity by attenuating ferroptosis through modulating the MAPK signaling pathway

Doxorubicin (Dox) is a widely used antitumor agent with dose-dependent and cumulative cardiotoxic effects. Resveratrol (Res) is a natural non-flavonoid polyphenol that can potentially provide cardiovascular benefits. We aimed to estimate the protective effect of Res on Dox-induced cardiotoxicity (DIC) and explore whether it was related to attenuating ferroptosis. We established DIC models in C57BL/6 J mice, H9C2 cardiomyoblasts, and neonatal rat cardiomyocytes (NRCMs). We further treated H9C2 cells with RSL3, a ferroptosis agonist, to investigate whether Res exerted protective effects through inhibiting ferroptosis. Ferrostatin-1 (Fer-1) was applied to suppress ferroptosis. Dox treatment caused cardiac dysfunction and resulted in apparent ferroptotic damage in cardiac tissue, involving increased iron accumulation, glutathione depletion, increased expression of ferroptosis-related proteins, and decreased expression of glutathione peroxidase 4, which were alleviated by Fer-1 and Res administration. These findings were also confirmed in Dox-treated H9C2 cells and NRCMs, with Fer-1 and Res effectively attenuating Dox-induced cytotoxicity and ferroptosis. Furthermore, Res protected H9C2 cells from RSL3-induced ferroptotic cell death, and the protective effect was similar to that of Fer-1. Both Dox and RSL3 treatment increased the phosphorylation levels of mitogen-activated protein kinases (MAPKs), including extracellular signal-regulated kinase, p38, and c-Jun N-terminal kinases; however, these changes were hindered by Res. This study demonstrates that Res effectively alleviates DIC by suppressing ferroptosis possibly through modulating the MAPK signaling pathway. Our results highlight that targeting ferroptosis can be a potential cardioprotective strategy for DIC.

A combination of isoliquiritigenin with Artemisia argyi and Ohwia caudata water extracts attenuates oxidative stress, inflammation, and apoptosis by modulating Nrf2/Ho-1 signaling pathways in SD rats with doxorubicin-induced acute cardiotoxicity

Ohwia caudata (Thunb.) H. Ohashi (Leguminosae) also called as "Evergreen shrub" and Artemisia argyi H.Lév. and Vaniot (Compositae) also named as "Chinese mugwort" those two-leaf extracts frequently used as herbal medicine, especially in south east Asia and eastern Asia. Anthracyclines such as doxorubicin (DOX) are commonly used as effective chemotherapeutic drugs in anticancer therapy around the world. However, chemotherapy-induced cardiotoxicity, dilated cardiomyopathy, and congestive heart failure are seen in patients who receive DOX therapy, with the mechanisms underlying DOX-induced cardiac toxicity remaining unclear. Mitochondrial dysfunction, oxidative stress, inflammatory response, and cardiomyocytes have been shown to play crucial roles in DOX-induced cardiotoxicity. Isoliquiritigenin (ISL, 10 mg/kg) is a bioactive flavonoid compound with protective effects against inflammation, neurodegeneration, cancer, and diabetes. Here, in this study, our aim is to find out the Artemisia argyi (AA) and Ohwia caudata (OC) leaf extract combination with Isoliquiritigenin in potentiating and complementing effect against chemo drug side effect to ameliorate cardiac damage and improve the cardiac function. In this study, we showed that a combination of low (AA 300 mg/kg; OC 100 mg/kg) and high-dose(AA 600 mg/kg; OC 300 mg/kg) AA and OC water extract with ISL activated the cell survival-related AKT/PI3K signaling pathway in DOX-treated cardiac tissue leading to the upregulation of the antioxidant markers SOD, HO-1, and Keap-1 and regulated mitochondrial dysfunction through the Nrf2 signaling pathway. Moreover, the water extract of AA and OC with ISL inhibited the inflammatory response genes IL-6 and IL-1β, possibly through the NFκB/AKT/PI3K/p38α/NRLP3 signaling pathways. The water extract of AA and OC with ISL could be a potential herbal drug treatment for cardiac hypertrophy, inflammatory disease, and apoptosis, which can lead to sudden heart failure.

Nanobiotechnology-based strategies in alleviation of chemotherapy-mediated cardiotoxicity

The cardiovascular diseases have been among the most common malignancies and the first leading cause of death, even higher than cancer. The cardiovascular diseases can be developed as a result of cardiac dysfunction and damages to heart tissue. Exposure to toxic agents and chemicals that induce cardiac dysfunction has been of interest in recent years. The chemotherapy drugs are commonly used for cancer therapy and in these patients, cardiovascular diseases have been widely observed that is due to negative impact of chemotherapy drugs on the heart. These drugs increase oxidative damage and inflammation, and mediate apoptosis and cardiac dysfunction. Hence, nanotechnological approaches have been emerged as new strategies in attenuation of chemotherapy-mediated cardiotoxicity. The first advantage of nanoparticles can be explored in targeted and selective delivery of drugs to reduce their accumulation in heart tissue. Nanostructures can deliver bioactive and therapeutic compounds in reducing cardiotoxicity and alleviation toxic impacts of chemotherapy drugs. The functionalization of nanostructures increases their selectivity against tumor cells and reduces accumulation of drugs in heart tissue. The bioplatforms such as chitosan and alginate nanostructures can also deliver chemotherapy drugs and reduce their cardiotoxicity. The function of nanostructures is versatile in reduction of cardiotoxicity by chemotherapy drugs and new kind of platforms is hydrogels that can mediate sustained release of drug to reduce its toxic impacts on heart tissue. The various kinds of nanoplatforms have been developed for alleviation of cardiotoxicity and their future clinical application depends on their biocompatibility. High concentration level of chitosan nanoparticles can stimulate cardiotoxicity. Therefore, if nanotechnology is going to be deployed for drug delivery and reducing cardiotoxicity, the first pre-requirement is to lack toxicity on normal cells and have high biocompatibility.

Doxorubicin-mediated cardiac dysfunction: Revisiting molecular interactions, pharmacological compounds and (nano)theranostic platforms

Although chemotherapy drugs are extensively utilized in cancer therapy, their administration for treatment of patients has faced problems that regardless of chemoresistance, increasing evidence has shown concentration-related toxicity of drugs. Doxorubicin (DOX) is a drug used in treatment of solid and hematological tumors, and its function is based on topoisomerase suppression to impair cancer progression. However, DOX can also affect the other organs of body and after chemotherapy, life quality of cancer patients decreases due to the side effects. Heart is one of the vital organs of body that is significantly affected by DOX during cancer chemotherapy, and this can lead to cardiac dysfunction and predispose to development of cardiovascular diseases and atherosclerosis, among others. The exposure to DOX can stimulate apoptosis and sometimes, pro-survival autophagy stimulation can ameliorate this condition. Moreover, DOX-mediated ferroptosis impairs proper function of heart and by increasing oxidative stress and inflammation, DOX causes cardiac dysfunction. The function of DOX in mediating cardiac toxicity is mediated by several pathways that some of them demonstrate protective function including Nrf2. Therefore, if expression level of such protective mechanisms increases, they can alleviate DOX-mediated cardiac toxicity. For this purpose, pharmacological compounds and therapeutic drugs in preventing DOX-mediated cardiotoxicity have been utilized and they can reduce side effects of DOX to prevent development of cardiovascular diseases in patients underwent chemotherapy. Furthermore, (nano)platforms are used comprehensively in treatment of cardiovascular diseases and using them for DOX delivery can reduce side effects by decreasing concentration of drug. Moreover, when DOX is loaded on nanoparticles, it is delivered into cells in a targeted way and its accumulation in healthy organs is prevented to diminish its adverse impacts. Hence, current paper provides a comprehensive discussion of DOX-mediated toxicity and subsequent alleviation by drugs and nanotherapeutics in treatment of cardiovascular diseases.

Nrf2: a dark horse in doxorubicin-induced cardiotoxicity

Being a broad-spectrum anticancer drug, doxorubicin is indispensable for clinical treatment. Unexpectedly, its cardiotoxic side effects have proven to be a formidable obstacle. Numerous studies are currently devoted to elucidating the pathological mechanisms underlying doxorubicin-induced cardiotoxicity. Nrf2 has always played a crucial role in oxidative stress, but numerous studies have demonstrated that it also plays a vital part in pathological mechanisms like cell death and inflammation. Numerous studies on the pathological mechanisms associated with doxorubicin-induced cardiotoxicity demonstrate this. Several clinical drugs, natural and synthetic compounds, as well as small molecule RNAs have been demonstrated to prevent doxorubicin-induced cardiotoxicity by activating Nrf2. Consequently, this study emphasizes the introduction of Nrf2, discusses the role of Nrf2 in doxorubicin-induced cardiotoxicity, and concludes with a summary of the therapeutic modalities targeting Nrf2 to ameliorate doxorubicin-induced cardiotoxicity, highlighting the potential value of Nrf2 in doxorubicin-induced cardiotoxicity.

An integrative review of nonobvious puzzles of cellular and molecular cardiooncology

Oncologic patients are subjected to four major treatment types: surgery, radiotherapy, chemotherapy, and immunotherapy. All nonsurgical forms of cancer management are known to potentially violate the structural and functional integrity of the cardiovascular system. The prevalence and severity of cardiotoxicity and vascular abnormalities led to the emergence of a clinical subdiscipline, called cardiooncology. This relatively new, but rapidly expanding area of knowledge, primarily focuses on clinical observations linking the adverse effects of cancer therapy with deteriorated quality of life of cancer survivors and their increased morbidity and mortality. Cellular and molecular determinants of these relations are far less understood, mainly because of several unsolved paths and contradicting findings in the literature. In this article, we provide a comprehensive view of the cellular and molecular etiology of cardiooncology. We pay particular attention to various intracellular processes that arise in cardiomyocytes, vascular endothelial cells, and smooth muscle cells treated in experimentally-controlled conditions in vitro and in vivo with ionizing radiation and drugs representing diverse modes of anti-cancer activity.

Current Status of Obesity: Protective Role of Catechins

Obesity is a growing health concern in today's society. Current estimates indicate that obesity occurs in both adults and young people. Recent research also found that the Hispanic population in the U.S. is 1.9 times more likely to be overweight as compared to their non-Hispanic population. Obesity is a multifactorial disease that has a variety of causes. All current treatment options incorporate dietary changes aimed at establishing a negative energy balance. According to current scientific research, multiple factors are involved with the development of obesity, including genetic, biochemical, psychological, environmental, behavioral, and socio-demographic factors. The people who suffer from obesity are far more likely to suffer serious health problems, such as stroke, diabetes, lung disease, bone and joint disease, cancer, heart disease, neurological disorders, and poor mental health. Studies indicate that multiple cellular changes are implicated in the progression of obesity, mitochondrial dysfunction, deregulated microRNAs, inflammatory changes, hormonal deregulation, and others. This article highlights the role that oxidative stress plays in obesity and current obesity-prevention techniques with an emphasis on the impact of catechins to prevent and treat obesity.

The Anti-inflammatory Effect of Chitosan Oligosaccharide on Heart Failure in Mice

Heart failure is currently one of the leading causes of death worldwide, and the inflammatory factors play an important role in its development. Chitosan oligosaccharide (COS), a low-molecular-weight form of chitosan, has many specific biological activities. In this study, COS effects on heart failure were studied for the first time by performing transverse arch constriction (TAC) surgery in mice, as an animal model of heart failure. Our findings revealed that COS administration (in both 40 mg/kg and 80 mg/kg doses) significantly ameliorated TCA-induced left ventricular (LV) hypertrophy as well as the increase in lung and heart weight in mice, while improving TAC-induced LV dysfunction. Both doses effectively attenuated LV cardiomyocyte hypertrophy, while decreasing heart inflammation after heart failure in mice. In conclusion, our results indicated that the supplementation of COS in normal diet might be an effective way to prevent further myocardial tissue damage in patients suffering from heart failure.

Modulation of integrin receptor by polyphenols: Downstream Nrf2-Keap1/ARE and associated cross-talk mediators in cardiovascular diseases

As a group of heterodimeric and transmembrane glycoproteins, integrin receptors are widely expressed in various cell types overall the body. During cardiovascular dysfunction, integrin receptors apply inhibitory effects on the antioxidative pathways, including nuclear factor erythroid 2-related factor 2 (Nrf2)-Kelch like ECH Associated Protein 1 (Keap1)/antioxidant response element (ARE) and interconnected mediators. As such, dysregulation in integrin signaling pathways influences several aspects of cardiovascular diseases (CVDs) such as heart failure, arrhythmia, angina, hypertension, hyperlipidemia, platelet aggregation and coagulation. So, modulation of integrin pathway could trigger the downstream antioxidant pathways toward cardioprotection. Regarding the involvement of multiple aforementioned mediators in the pathogenesis of CVDs, as well as the side effects of conventional drugs, seeking for novel alternative drugs is of great importance. Accordingly, the plant kingdom could pave the road in the treatment of CVDs. Of natural entities, polyphenols are multi-target and accessible phytochemicals with promising potency and low levels of toxicity. The present study aims at providing the cardioprotective roles of integrin receptors and downstream antioxidant pathways in heart failure, arrhythmia, angina, hypertension, hyperlipidemia, platelet aggregation and coagulation. The potential role of polyphenols has been also revealed in targeting the aforementioned dysregulated signaling mediators in those CVDs.

Acadesine alleviates acute pancreatitis-related lung injury by mediating the barrier protective function of pulmonary microvascular endothelial cells

Severe acute pancreatitis (SAP) is a condition characterized by highly fatal acute inflammation and is usually associated with multiple organ dysfunction syndrome. Acute lung injury (ALI) is the most common complications of SAP, which is the accelerator of other organ dysfunction caused by SAP and the primary cause of early death due to SAP. Acadesine, an adenosine analog and an AMPK activator, has been discovered to modulate glucose and lipid metabolism, and inhibit the production of pro-inflammatory cytokines and iNOS. However, its role in SAP-ALI and its mechanism remains unclear and need to be explored. Herein, we discovered that acadesine mitigated the generation of reactive oxygen species (ROS) in human pulmonary microvascular endothelial cells (HPMECs), alleviated apoptosis and recovered barrier integrity, thereby contributing to anti-inflammatory effects in vitro and in vivo. Moreover, Nrf2 deficiency partially eliminated the effects of acadesine-induced antioxidant effects and thus weakened the protective effects on cells and Nrf2-knockout (Nrf2^-/-) mice. This study demonstrates that acadesine attenuated SAP-ALI associated inflammation and tissue damage by modulating the Nrf2-dependent antioxidant pathway by triggering AMPK. These findings are of great significance for the treatment of SAP-related lung injury.

Paeonol protects against doxorubicin-induced cardiotoxicity by promoting Mfn2-mediated mitochondrial fusion through activating the PKCε-Stat3 pathway

INTRODUCTION

The anti-cancer medication doxorubicin (Dox) is largely restricted in clinical usage due to its significant cardiotoxicity. The only medication approved by the FDA for Dox-induced cardiotoxicity is dexrazoxane, while it may reduce the sensitivity of cancer cells to chemotherapy and is restricted for use. There is an urgent need for the development of safe and effective medicines to alleviate Dox-induced cardiotoxicity.

OBJECTIVES

The objective of this study was to determine whether Paeonol (Pae) has the ability to protect against Dox-induced cardiotoxicity and if so, what are the underlying mechanisms involved.

METHODS

Sprague-Dawley rats and primary cardiomyocytes were used to create Dox-induced cardiotoxicity models. Pae's effects on myocardial damage, mitochondrial function, mitochondrial dynamics and signaling pathways were studied using a range of experimental methods.

RESULTS

Pae enhanced Mfn2-mediated mitochondrial fusion, restored mitochondrial function and cardiac performance both in vivo and in vitro under the Dox conditions. The protective properties of Pae were blunted when Mfn2 was knocked down or knocked out in Dox-induced cardiomyocytes and hearts respectively. Mechanistically, Pae promoted Mfn2-mediated mitochondria fusion by activating the transcription factor Stat3, which bound to the Mfn2 promoter in a direct manner and up-regulated its transcriptional expression. Furthermore, molecular docking, surface plasmon resonance and co-immunoprecipitation studies showed that Pae's direct target was PKCε, which interacted with Stat3 and enabled its phosphorylation and activation. Pae-induced Stat3 phosphorylation and Mfn2-mediated mitochondrial fusion were inhibited when PKCε was knocked down. Furthermore, Pae did not interfere with Dox's antitumor efficacy in several tumor cells.

CONCLUSION

Pae protects the heart against Dox-induced damage by stimulating mitochondrial fusion via the PKCε-Stat3-Mfn2 pathway, indicating that Pae might be a promising therapeutic therapy for Dox-induced cardiotoxicity while maintaining Dox's anticancer activity.

[Islet biomimetic microenvironment constructed by chitosan oligosaccharide protects islets from hypoxia-induced damage by reducing intracellular reactive oxygen species]

Objective

Gelatin methacryloyl (GelMA)/hyaluronic acid methacryloyl (HAMA)/chitosan oligosaccharide (COS) hydrogel was used to construct islet biomimetic microenvironment, and to explore the improvement effect of GelMA/HAMA/COS on islet activity and function under hypoxia.

Methods

Islets cultured on the tissue culture plate was set as the control group, on the GelMA/HAMA/COS hydrogel with COS concentrations of 0, 1, 5, 10, and 20 mg/mL respectively as the experimental groups. Scanning electron microscopy was used to observe the microscopic morphology, rheometer test to evaluate the gel-forming properties, contact angle to detect the hydrophilicity, and the biocompatibility was evaluated by the scaffold extract to L929 cells [using cell counting kit 8 (CCK-8) assay]. The islets were extracted from the pancreas of 8-week-old Sprague Dawley rats and the islet purity and function were identified by dithizone staining and glucose-stimulated insulin secretion (GSIS) assays, respectively. Islets were cultured under hypoxia (1%O 2) for 24, 48, and 72 hours, respectively. Calcein-acetyl methyl/propidium iodide (Calcein-AM/PI) staining was used to evaluate the effect of hypoxia on islet viability. Islets were cultured in GelMA/HAMA/COS hydrogels with different COS concentrations for 48 hours, and the reactive oxygen species kits were used to evaluate the antagonism of COS against islet reactive oxygen species production under normoxia (20%O 2) and hypoxia (1%O 2) conditions. Calcein-AM/PI staining was used to evaluate the effect of COS on islet activity under hypoxia (1%O 2) conditions. Islets were cultured in tissue culture plates (group A), GelMA/HAMA hydrogels (group B), and GelMA/HAMA/COS hydrogels (group C) for 48 hours, respectively. Immunofluorescence and GSIS assays were used to evaluate the effect of COS on islet activity under hypoxia (1%O 2) conditions, respectively.

Results

GelMA/HAMA/COS hydrogel had a porous structure, the rheometer test showed that it had good gel-forming properties, and the contact angle test showed good hydrophilicity. CCK-8 assay showed that the hydrogel in each group had good biocompatibility. The isolated rat islets were almost round, with high islet purity and insulin secretion ability. Islets were treated with hypoxia for 24, 48, and 72 hours, Calcein-AM/PI staining showed that the number of dead cells gradually increased with time, which were significantly higher than those in the non-hypoxia-treated group ( P<0.001). Reactive oxygen staining showed that GelMA/HAMA/COS hydrogels with different COS concentrations could antagonize the production of reactive oxygen under normal oxygen and hypoxia conditions, and this ability was positively correlated with COS concentration. Calcein-AM/PI staining indicated that GelMA/HAMA/COS hydrogels with different COS concentrations could improve islet viability under hypoxia conditions, and cell viability was positively correlated with COS concentration. Immunofluorescence staining showed that GelMA/HAMA/COS hydrogel could promote the expression of islet function-related genes under hypoxia conditions. GSIS assay results showed that the insulin secretion of islets in hypoxia condition of group C was significantly higher than that of groups B and C ( P<0.05).

Conclusion

GelMA/HAMA/COS hydrogel has good biocompatibility, promotes islet survival and function by inhibiting reactive oxygen species, and is an ideal carrier for building islet biomimetic microenvironment for islet culture and transplantation.

Dietary Chitosan Supplementation Improved Egg Production and Antioxidative Function in Laying Breeders

Simple Summary

Chitosan is a natural, non-toxic and biodegradable compound, which has antibacterial, antioxidant and anti-tumor properties. Several studies have shown that chitosan also improve the antioxidant capacity of poultry. Recent research showed that chitosan decreased oxidative damage by activating the nuclear factor erythroid-2 related factor 2 pathway, then elevated the meat quality of broilers. Egg breeders are susceptible to oxidative stress during peak egg production, which increase their susceptibility to diseases and lead performance decline. In addition, previous reports on the effect of chitosan on poultry production performance were inconsistent. Based on above reports, this study explored whether chitosan could promote the production performance, and antioxidant defense of laying hens by affecting the nuclear factor erythroid-2 related factor 2 pathway. The results showed that addition chitosan to layer hen diet could increase egg production and feed conversion ratio, and the effect was better at the level of 250~500 mg/kg; as well as, chitosan promoted the antioxidant status in serum, liver and duodenum tissues and the effect was better at the level of 500 mg/kg. Chitosan was likely to increase antioxidant enzyme activities by enhancing the expression of nuclear factor erythroid-2 related factor 2, thereby improving the antioxidant capacity of laying breeders.

Abstract

This study was conducted to explore the dietary effect of chitosan on the production performance, and antioxidative enzyme activities and corresponding gene expression in the liver and duodenum of laying breeders. A total of 450 laying breeders (92.44% ± 0.030% of hen-day egg production) were randomly assigned to five dietary treatments fed 8 weeks: maize-soybean meal as the basal control diet and the basal diet containing 250, 500, 1000 and 2000 mg/kg of chitosan, respectively. Each treatment was randomly divided into 6 equal replicates, with 15 laying breeders in each replicate. The results showed that dietary chitosan could increase hen-day egg production and feed conversion ratio, especially at the level of 250~500 mg/kg; however, chitosan had no prominent effect on feed intake and average egg weight. Dietary chitosan could dose-dependently promote the antioxidant status in serum, liver and duodenum of layer breeders. It has a better promotion effect at the level of 500 mg/kg; however, the effect was weakened at the level of 2000 mg/kg. Chitosan was likely to enhance the gene expression and activities of Nrf2-mediated phase II detoxification enzyme by up-regulating the expression of Nrf2, thereby improving the antioxidant capacity of laying breeder hens.

Endogenous Hydrogen Sulfide Persulfidates Caspase-3 at Cysteine 163 to Inhibit Doxorubicin-Induced Cardiomyocyte Apoptosis

Doxorubicin (DOX) is an efficient antitumor anthracycline drug, but its cardiotoxicity adversely affects the prognosis of the patients. In this study, we explored whether endogenous gasotransmitter hydrogen sulfide (H₂S) could protect against DOX-induced cardiomyocyte apoptosis and its mechanisms. The results indicated that DOX significantly downregulated endogenous H₂S production and endogenous synthetase cystathionine γ-lyase (CSE) expression and obviously stimulated the apoptosis in H9C2 cells. The supplement of H₂S donor sodium hydrosulfide (NaHS) or overexpression of CSE inhibited DOX-induced H9C2 cell apoptosis. DOX enhanced the activities of caspase family members in cardiomyocytes, while NaHS attenuated DOX-enhanced caspase-3, caspase-2, and caspase-9 activities by 223.1%, 73.94%, and 52.29%, respectively. Therefore, taking caspase-3 as a main target, we demonstrated that NaHS or CSE overexpression alleviated the cleavage of caspase-3, suppressed caspase-3 activity, and inhibited the cleavage of poly ADP-ribose polymerase (PARP). Mechanistically, we found that H₂S persulfidated caspase-3 in H9C2 cells and human recombinant caspase-3 protein, while the thiol-reducing agent dithiothreitol (DTT) abolished H₂S-induced persulfidation of caspase-3 and thereby prevented the antiapoptotic effect of H₂S on caspase-3 in H9C2 cells. The mutation of caspase-3 C148S and C170S failed to block caspase-3 persulfidation by H₂S in H9C2 cells. However, caspase-3 C163S mutation successfully abolished the effect of H₂S on caspase-3 persulfidation and the corresponding protection of H9C2 cells. Collectively, these findings indicate that endogenous H₂S persulfidates caspase-3 at cysteine 163, inhibiting its activity and cardiomyocyte apoptosis. Sufficient endogenous H₂S might be necessary for the protection against myocardial cell apoptosis induced by DOX. The results of the study might open new avenues with respect to the therapy of DOX-stimulated cardiomyopathy.

Ferroptosis-Specific Inhibitor Ferrostatin-1 Relieves H2O2-Induced Redox Imbalance in Primary Cardiomyocytes through the Nrf2/ARE Pathway

Objective

Ischemic heart disease (IHD) has always been the focus of attention of many researchers in cardiovascular disease, and its pathogenesis is also very complicated. Ferroptosis may be involved in the occurrence and development of IHD.

Methods

First, primary cardiomyocytes were treated with H₂O₂ to simulate the IHD in vitro model. After pretreatment with different concentrations of ferrostatin-1, cell survival rate was detected by MTT method, cell apoptosis was detected by TUNEL staining and flow cytometry, and the expression of oxidative stress, ferroptosis, and related molecules of Nrf2/ARE pathway was detected by Western blotting (WB) and quantitative real-time polymerase chain reaction (qRT-PCR).

Results

The mortality of primary cardiomyocytes in the H₂O₂ group was obviously increased. Ferrostatin-1 treatment can effectively inhibit cell death, improve antioxidant enzyme activity, inhibit the expression of ferroptosis-related molecules, and activate Nrf2/ARE pathway expression.

Conclusion

Ferroptosis-specific inhibitor ferrostatin-1 relieves H₂O₂-induced redox imbalance in primary cardiomyocytes through the Nrf2/ARE pathway, inhibits ferroptosis, and thereby slows cardiomyocyte death.

The Role of Flavonoids as a Cardioprotective Strategy against Doxorubicin-Induced Cardiotoxicity: A Review

Doxorubicin is a widely used and promising anticancer drug; however, a severe dose-dependent cardiotoxicity hampers its therapeutic value. Doxorubicin may cause acute and chronic issues, depending on the duration of toxicity. In clinical practice, the accumulative toxic dose is up to 400 mg/m² and increasing the dose will increase the probability of cardiac toxicity. Several molecular mechanisms underlying the pathogenesis of doxorubicin cardiotoxicity have been proposed, including oxidative stress, topoisomerase beta II inhibition, mitochondrial dysfunction, Ca²⁺ homeostasis dysregulation, intracellular iron accumulation, ensuing cell death (apoptosis and necrosis), autophagy, and myofibrillar disarray and loss. Natural products including flavonoids have been widely studied both in cell, animal, and human models which proves that flavonoids alleviate cardiac toxicity caused by doxorubicin. This review comprehensively summarizes cardioprotective activity flavonoids including quercetin, luteolin, rutin, apigenin, naringenin, and hesperidin against doxorubicin, both in in vitro and in vivo models.

Lactobacillus plantarum DP189 Reduces α-SYN Aggravation in MPTP-Induced Parkinson's Disease Mice via Regulating Oxidative Damage, Inflammation, and Gut Microbiota Disorder

This study aimed to evaluate the attenuating effect of Lactobacillus plantarum DP189 on α-synuclein (α-SYN) aggregates in the substantia nigra (SN) of Parkinson's disease (PD) mice via 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced. Our results indicated that L. plantarum DP189 increased the levels of superoxide dismutase (SOD), glutathione peroxide (GSH-Px), and interleukin-10 (IL-10) and decreased the levels of malondialdehyde (MDA), reactive oxygen species (ROS), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β). Moreover, L. plantarum DP189 reduced the α-SYN accumulation in SN. Mechanistically, L. plantarum DP189 activated the expression of nuclear factor erythroid 2-related factor (Nrf2)/ARE and PGC-1α pathways and suppressed the NLRP3 inflammasome. Furthermore, fecal analysis showed that L. plantarum DP189 reshaped the gut microbiota in PD mice by reducing the number of pathogenic bacteria (Proteobacteria and Actinobacteria) and increased the abundance of probiotics (Lactobacillus and Prevotella). Our results suggested that L. plantarum DP189 could delay the neurodegeneration caused by the accumulation of α-SYN in the SN of PD mice via suppressing oxidative stress, repressing proinflammatory response, and modulating gut microbiota.

Nrf2 for protection against oxidant generation and mitochondrial damage in cardiac injury

Myocardial infarction is the most common form of acute coronary syndrome. Blockage of a coronary artery due to blood clotting leads to ischemia and subsequent cell death in the form of necrosis, apoptosis, necroptosis and ferroptosis. Revascularization by coronary artery bypass graft surgery or non-surgical percutaneous coronary intervention combined with pharmacotherapy is effective in relieving symptoms and decreasing mortality. However, reactive oxygen species (ROS) are generated from damaged mitochondria, NADPH oxidases, xanthine oxidase, and inflammation. Impairment of mitochondria is shown as decreased metabolic activity, increased ROS production, membrane permeability transition, and release of mitochondrial proteins into the cytoplasm. Oxidative stress activates Nrf2 transcription factor, which in turn mediates the expression of mitofusin 2 (Mfn 2) and proteasomal genes. Increased expression of Mfn2 and inhibition of mitochondrial fission due to decreased Drp1 protein by proteasomal degradation contribute to mitochondrial hyperfusion. Damaged mitochondria can be removed by mitophagy via Parkin or p62 mediated ubiquitination. Mitochondrial biogenesis compensates for the loss of mitochondria, but requires mitochondrial DNA replication and initiation of transcription or translation of mitochondrial genes. Experimental evidence supports a role of Nrf2 in mitophagy, via up-regulation of PINK1 or p62 gene expression; and in mitochondrial biogenesis, by influencing the expression of PGC-1α, NResF1, NResF2, TFAM and mitochondrial genes. Oxidative stress causes Nrf2 activation via Keap1 dissociation, de novo protein translation, and nuclear translocation related to inactivation of GSK3β. The mechanism of Keap 1 mediated Nrf2 activation has been hijacked for Nrf2 activation by small molecules derived from natural products, some of which have been shown capable of mitochondrial protection. Multiple lines of evidence support the importance of Nrf2 in protecting mitochondria and preserving or renewing energy metabolism following tissue injury.

Salidroside alleviates oxidative stress and apoptosis via AMPK/Nrf2 pathway in DHT-induced human granulosa cell line KGN

In the past few years, emerging evidence established persistent oxidative stress to be a key player in the pathogenesis of polycystic ovary syndrome (PCOS). Particularly, it damages the function of granulosa cells, and thus hinders the development of follicles. The present study aimed to explore and establish the protective effects of salidroside on dihydrotestosterone (DHT)-induced Granulosa-like tumor cell line (KGN), mediated via antioxidant mechanisms. The study assessed the positive effects of salidroside on DHT-induced apoptosis, reactive oxygen species (ROS) accumulation, damage of antioxidant capacity, and mitochondrial membrane potential depolarization. Interestingly, salidroside partly reversed DHT mediated effects, via stimulation of nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway and the downstream antioxidant proteins heme oxygenase-1(HO-1) and quinine oxidoreductase 1(NQO1). Additionally, the knockdown of Nrf2 partly moderated the antioxidant and anti-apoptosis effects of salidroside in DHT-treated KGN cells. Mechanistically, AMP-activated protein kinase (AMPK) was identified to be the upstream signaling involved in salidroside-induced Nrf2 activation, as silencing of AMPK partly prevented the upregulation of Nrf2 and the downstream proteins HO-1 and NQO1. Altogether, the present study is the first to effectively demonstrate the inhibitory effect of salidroside on DHT-stimulated oxidative stress and apoptosis in KGN cells, which was dependent on Nrf2 activation that involved AMPK.

Dietary chitooligosaccharide supplementation alleviates intestinal barrier damage, and oxidative and immunological stress in lipopolysaccharide-challenged laying hens

This study aimed to investigate the effects of chitooligosaccharide (COS) on intestinal barrier, antioxidant capacity, and immunity of lipopolysaccharide (LPS)-challenged laying hens. A total of 360 Hy-line Brown laying hens (80-wk-old) were randomly divided into 5 groups with 6 replicates of 12 birds. Hens were fed a corn-soybean meal basal diet supplemented with different COS levels (0; 5; 10; 15; 20 mg/kg) for 8 wk. The results showed that 15 mg/kg COS administration elevated albumen height and Haugh unit (P < 0.05), and numerically optimized productive performance (P > 0.05), therefore, the dosage of 15 mg/kg was chosen for the subsequent experiment. Thereafter, 12 birds from non-supplemented group were randomly selected and assigned into 2 groups, and birds in each group were administered (1.5 mg/kg BW, i.p.) with saline (control group) or LPS (challenge group). Another 6 hens from 15 mg/kg COS-supplemented group were selected and injected with LPS in the same way. Compared with the control group, LPS-challenged birds exhibited elevated circulating diamine oxidase activity, and reduced jejunal villus height and ratio of villus height to crypt depth, and these indices were reversed to control levels by COS (P < 0.05). Also, LPS increased malondialdehyde accumulation and reduced several antioxidant enzyme activities in the intestinal mucosa (P < 0.05). Additionally, LPS increased jejunal secretory IgA and interferon-γ (IFN-γ), and ileal secretory IgA, IgM, and interleukin-1β (IL-1β) concentrations, whereas COS reduced jejunal IFN-γ and IL-1β, and ileal IgM levels (P < 0.05). Moreover, LPS down-regulated mRNA abundance of jejunal occludin and claudin 2, and upregulated expression of jejunal nuclear factor erythroid-2 related factor 2, superoxide dismutase 1, and IFN-γ as well as ileal IL-1β (P < 0.05). Besides, COS increased jejunal occludin and ileal claudin 2, nuclear factor erythroid-2 related factor 2, and heme oxygenase-1 expression, and decreased jejunal IFN-γ and IL-1β abundance (P < 0.05). These results suggested that COS could alleviate LPS-induced intestinal barrier impairment, and oxidative and immunological stress in laying hens.

Protective Effect of Chitosan Oligosaccharide against Hydrogen Peroxide-Mediated Oxidative Damage and Cell Apoptosis via Activating Nrf2/ARE Signaling Pathway

Chitosan oligosaccharide (COS), hydrolyzed and deacetylated from chitosan, has been reported to possess varieties of biological activities. Alzheimer's disease (AD) is a multifactorial progressive neurodegenerative disorder characterized by cognitive decline and memory loss, where oxidative stress was reported to be an overwhelming cause of the occurrence of AD. We have previously reported that COS could significantly decrease cell death, ROS generation, and lipid peroxidation, though the potential mechanism was yet to be determined. This study was designed to investigate the neuroprotective effect of COS against hydrogen peroxide (H2O2)-induced oxidative stress and apoptosis in neuronal SH-SY5Y cells. Our results indicated that COS could dose-dependently scavenge H2O2 in the cell-free systems. Accordingly, COS markedly decreased H2O2-induced cell apoptosis and intracellular ROS generation, while increased antioxidant capacity in SH-SY5Y cells. Further, COS significantly reduced the expression of Bax and upregulated Bcl-2. The mRNA and protein expression levels of nuclear Nrf2, heme oxygenase 1 (HO-1), and NAD(P)H: quinone oxidoreductase 1 (NQO1) were significantly increased upon COS treatment. Moreover, Nrf2-siRNA evidently reversed the promotive effect of COS on expression levels of HO-1 and NQO1, and ARE-driven transcriptional activity as determined by double-luciferase reporter gene assay. Besides, COS reversed H2O2-mediated increased phosphorylation of ERK1/2 and p38 MAPK. In conclusion, our findings indicate that COS could protect SH-SY5Y cells from oxidative damage and apoptosis via regulating Nrf2/ARE signaling pathway, which may provide new applications for the prevention and treatment of AD.

Chitosan oligosaccharides alleviate acute heat stress-induced oxidative damage by activating ERK1/2-mediated HO-1 and GSH-Px gene expression in breast muscle of broilers

The purpose of this study was to evaluate the effects of chitosan oligosaccharides (COS) on acute heat stress (AHS) induced poor meat quality by alleviating oxidative damage through mitogen-activated protein kinase-nuclear factor-erythroid 2-related factor 2-antioxidant responsive element (MAPK-Nrf2-ARE) signaling pathway. A total of 108 thirty-five-day-old Chinese indigenous broilers (Luhua chicken) was used for this 42-d experiment. The broilers were randomly allocated to 3 treatments: control group (CON), AHS group, and AHS with 400 mg/kg COS supplementation (AHS-C) group. Both CON and AHS groups given the basal diet, and the AHS-C group given the basal diet with 400 mg/kg COS supplementation. On d 42, broilers in the AHS and AHS-C groups treated with AHS (increasing temperature from 24 to 34°C in 2-h and held for another 2-h), and the CON group under normal temperature (24°C). AHS exposure elevated (P < 0.05) body temperature (rectal, comb, eyelids, and feet) of broilers, increased (P < 0.05) breast muscle lightness (L*), drip loss, share force, hydrogen peroxide (H₂O₂) scavenging activity, reactive oxygen species (ROS) production, malondialdehyde (MDA) content, and catalase (CAT) activity, however, decreased (P < 0.05) pH_45min, pH_24h, redness (a*), and relative expression of heme oxygenase-1 (HO-1). Compared to the AHS group, dietary COS supplementation increased (P < 0.05) breast muscle pH_45min, pH_24h, and a*, H₂O₂ scavenging activity, as well as relative expression of HO-1 and glutathione peroxidase (GSH-Px), however, decreased (P < 0.05) drip loss, share force, superoxide anion free radicals (O₂^•−) scavenging activity, ROS production, and MDA content. It was concluded that AHS impaired meat quality, which may be related to oxidative damage, as evidenced by increasing ROS production, MDA content, and decreasing the relative expression of HO-1. Dietary COS supplementation could effectively elevate the meat quality of broilers exposed to AHS via decreasing ROS production, activating the Nrf2 pathway, and Nrf2-mediated HO-1 and GSH-Px gene expression.

MSCs enhances the protective effects of valsartan on attenuating the doxorubicin-induced myocardial injury via AngII/NOX/ROS/MAPK signaling pathway

OBJECTIVE

To verify if AngII/NOX/ROS/MAPK signaling pathway is involved in Doxorubicin (DOX)-induced myocardial injury and if mesenchymal stem cells (MSCs) could enhance the protective effects of valsartan (Val) on attenuating DOX-induced injury in vitro.

METHODS

Reactive oxygen species (ROS) formation and the protein expression of AT1R, NOX2, NOX4, caspase-3, caspase-9 and MAPK signaling were assessed in H9c2 cardiomyocytes exposed to DOX for 24 h in the absence or presence of Val, NADPH oxidase inhibitor DPI or knockdown and overexpression of NADPH oxidase subunit: NOX2 and NOX4, co-culture with MSCs, respectively. Finally, MTT assay was used to determine the cell viability of H9c2 cells, MDA-MB-231 breast cancer cells and A549 pulmonary cancer cells under Val, DOX and Val+ DOX treatments.

RESULTS

DOX increased ROS formation and upregulated proteins expression of AT1R, NOX2, NOX4, caspase-3, caspase-9 and MAPK signaling including p-p38, p-JNK, p-ERK in H9c2 cells. These effects could be attenuated by Val, DPI, NOX2 siRNA and NOX4 siRNA. Meanwhile, overexpression of NOX2 and NOX4 could significantly increase DOX-induced ROS formation and further upregulate apoptotic protein expressions and protein expressions of MAPK signaling. MSCs on top of Val further enhanced the protective effects of Val on reducing the DOX-induced ROS formation and downregulating the expression of apoptotic proteins and MAPK signaling as compared with Val alone in DOX-treated H9c2 cells. Simultaneous Val and DOX treatment did not affect cell viability of DOX-treated MDA-MB-231 breast cancer cells or A549 pulmonary cancer cells but significantly improved cell viability of DOX-treated H9c2 cardiomyocytes.

CONCLUSIONS

AT1R/NOX/ROS/MAPK signaling pathway is involved in DOX-induced cardiotoxicity. Val treatment significantly attenuated DOX-induced cardiotoxicity, without affecting the anti-tumor effect of DOX. MSCs enhance the protective effects of Val on reducing the DOX-induced toxicity in H9c2 cells.

Marine Natural Products and Coronary Artery Disease

Coronary artery disease is the major cause of mortality worldwide, especially in low- and middle-income earners. To not only reduce angina symptoms and exercise-induced ischemia but also prevent cardiovascular events, pharmacological intervention strategies, including antiplatelet drugs, anticoagulant drugs, statins, and other lipid-lowering drugs, and renin-angiotensin-aldosterone system blockers, are conducted. However, the existing drugs for coronary artery disease are incomprehensive and have some adverse reactions. Thus, it is necessary to look for new drug research and development. Marine natural products have been considered a valuable source for drug discovery because of their chemical diversity and biological activities. The experiments and investigations indicated that several marine natural products, such as organic small molecules, polysaccharides, proteins, and bioactive peptides, and lipids were effective for treating coronary artery disease. Here, we particularly discussed the functions and mechanisms of active substances in coronary artery disease, including antiplatelet, anticoagulant, lipid-lowering, anti-inflammatory, and antioxidant activities.

Chitosan oligosaccharide attenuates endoplasmic reticulum stress-associated intestinal apoptosis via the Akt/mTOR pathway

Endoplasmic reticulum stress (ERS) and apoptosis are widely considered as essential factors associated with intestinal disorders, whereas nutritional therapeutic approaches targeting ERS may control disease activity. Thus, we focus on the potential benefit of chitosan oligosaccharide (COS) on repressing ERS and ERS-induced apoptosis. In this study, we used the ERS model with tunicamycin (TM)-induced IPEC-J2 cells in vitro and nutrient deprivation-induced ERS in piglets to evaluate the protective mechanism of COS against ERS and ERS-induced apoptosis. The results showed that cells were characterized by activation of the unfolded protein response (UPR) and increased epithelial apoptosis upon exposure to TM. However, these changes were significantly attenuated by COS and the expressions of Akt and mTORC1 were inhibited. Furthermore, a specific inhibitor of mTOR confirmed the suppression of Akt and reduced the activation of the UPR and apoptosis. In vivo, COS protected against nutrient deprivation-induced ERS in the jejunum of piglets, in which the overexpression of the UPR and apoptosis was rescued. Consistently, COS attenuated nutrient deprivation-induced disruption of intestinal barrier integrity and functional capacity. Together, we provided the first evidence that COS could protect against intestinal apoptosis through alleviating severe ERS, which may be related to the inhibition of the Akt/mTOR signaling pathway.

Cinnamic Acid Derivatives as Cardioprotective Agents against Oxidative and Structural Damage Induced by Doxorubicin

Doxorubicin (DOX) is a widely used anticancer drug. However, its clinical use is severely limited due to drug-induced cumulative cardiotoxicity, which leads to progressive cardiomyocyte dysfunction and heart failure. Enormous efforts have been made to identify potential strategies to alleviate DOX-induced cardiotoxicity; however, to date, no universal and highly effective therapy has been introduced. Here we reported that cinnamic acid (CA) derivatives exert a multitarget protective effect against DOX-induced cardiotoxicity. The experiments were performed on rat cardiomyocytes (H9c2) and human induced-pluripotent-stem-cell-derived cardiomyocytes (hiPSC-CMs) as a well-established model for cardiac toxicity assessment. CA derivatives protected cardiomyocytes by ameliorating DOX-induced oxidative stress and viability reduction. Our data indicated that they attenuated the chemotherapeutic’s toxicity by downregulating levels of caspase-3 and -7. Pre-incubation of cardiomyocytes with CA derivatives prevented DOX-induced motility inhibition in a wound-healing assay and limited cytoskeleton rearrangement. Detailed safety analyses—including hepatotoxicity, mutagenic potential, and interaction with the hERG channel—were performed for the most promising compounds. We concluded that CA derivatives show a multidirectional protective effect against DOX-induced cardiotoxicity. The results should encourage further research to elucidate the exact molecular mechanism of the compounds’ activity. The lead structure of the analyzed CA derivatives may serve as a starting point for the development of novel therapeutics to support patients undergoing DOX therapy.

Cardiac Protective Effect of Kirenol against Doxorubicin-Induced Cardiac Hypertrophy in H9c2 Cells through Nrf2 Signaling via PI3K/AKT Pathways

Kirenol (KRL) is a biologically active substance extracted from Herba Siegesbeckiae. This natural type of diterpenoid has been widely adopted for its important anti-inflammatory and anti-rheumatic properties. Despite several studies claiming the benefits of KRL, its cardiac effects have not yet been clarified. Cardiotoxicity remains a key concern associated with the long-term administration of doxorubicin (DOX). The generation of reactive oxygen species (ROS) causes oxidative stress, significantly contributing to DOX-induced cardiac damage. The purpose of the current study is to investigate the cardio-protective effects of KRL against apoptosis in H9c2 cells induced by DOX. The analysis of cellular apoptosis was performed using the terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining assay and measuring the modulation in the expression levels of proteins involved in apoptosis and Nrf2 signaling, the oxidative stress markers. Furthermore, Western blotting was used to determine cell survival. KRL treatment, with Nrf2 upregulation and activation, accompanied by activation of PI3K/AKT, could prevent the administration of DOX to induce cardiac oxidative stress, remodeling, and other effects. Additionally, the diterpenoid enhanced the activation of Bcl2 and Bcl-xL, while suppressing apoptosis marker proteins. As a result, KRL is considered a potential agent against hypertrophy resulting from cardiac deterioration. The study results show that KRL not only activates the IGF-IR-dependent p-PI3K/p-AKT and Nrf2 signaling pathway, but also suppresses caspase-dependent apoptosis.

Nrf2 Signaling Pathway in Chemoprotection and Doxorubicin Resistance: Potential Application in Drug Discovery

Doxorubicin (DOX) is extensively applied in cancer therapy due to its efficacy in suppressing cancer progression and inducing apoptosis. After its discovery, this chemotherapeutic agent has been frequently used for cancer therapy, leading to chemoresistance. Due to dose-dependent toxicity, high concentrations of DOX cannot be administered to cancer patients. Therefore, experiments have been directed towards revealing underlying mechanisms responsible for DOX resistance and ameliorating its adverse effects. Nuclear factor erythroid 2-related factor 2 (Nrf2) signaling is activated to increase levels of reactive oxygen species (ROS) in cells to protect them against oxidative stress. It has been reported that Nrf2 activation is associated with drug resistance. In cells exposed to DOX, stimulation of Nrf2 signaling protects cells against cell death. Various upstream mediators regulate Nrf2 in DOX resistance. Strategies, both pharmacological and genetic interventions, have been applied for reversing DOX resistance. However, Nrf2 induction is of importance for alleviating side effects of DOX. Pharmacological agents with naturally occurring compounds as the most common have been used for inducing Nrf2 signaling in DOX amelioration. Furthermore, signaling networks in which Nrf2 is a key player for protection against DOX adverse effects have been revealed and are discussed in the current review.

The Protect Effects of Chitosan Oligosaccharides on Intestinal Integrity by Regulating Oxidative Status and Inflammation under Oxidative Stress

The aim of this study was to evaluate the effects of the dietary supplementation of chitosan oligosaccharides (COS) on intestinal integrity, oxidative status, and the inflammation response with hydrogen peroxide (H₂O₂) challenge. In total, 30 rats were randomly assigned to three groups with 10 replications: CON group, basal diet; AS group, basal diet + 0.1% H₂O₂ in drinking water; ASC group, basal diet + 200 mg/kg COS + 0.1% H₂O₂ in drinking water. The results indicated that COS upregulated (p < 0.05) villus height (VH) of the small intestine, duodenum, and ileum; mucosal glutathione peroxidase activity; jejunum and ileum mucosal total antioxidant capacity; duodenum and ileum mucosal interleukin (IL)-6 level; jejunum mucosal tumor necrosis factor (TNF)-α level; duodenum and ileum mucosal IL-10 level; the mRNA expression level of zonula occludens (ZO)-1 in the jejunum and ileum, claudin in the duodenum, nuclear factor-erythroid 2-like 2 in the jejunum, and heme oxygenase-1 in the duodenum and ileum; and the protein expression of ZO-1 and claudin in jejunum; however, it downregulated (p < 0.05) serum diamine oxidase activity and D-lactate level; small intestine mucosal malondialdehyde content; duodenum and ileum mucosal IL-6 level; jejunum mucosal TNF-α level; and the mRNA expression of IL-6 in the duodenum and jejunum, and TNF-α in the jejunum and ileum. These results suggested COS could maintain intestinal integrity under oxidative stress by modulating the intestinal oxidative status and release of inflammatory cytokines.

Effects and Mechanisms of Chitosan and ChitosanOligosaccharide on Hepatic Lipogenesis and Lipid Peroxidation, Adipose Lipolysis, and Intestinal Lipid Absorption in Rats with High-Fat Diet-Induced Obesity

Chitosan and its derivative, chitosan oligosaccharide (CO), possess hypolipidemic and anti-obesity effects. However, it is still unclear if the mechanisms are different or similar between chitosan and CO. This study was designed to investigate and compare the effects of CO and high-molecular-weight chitosan (HC) on liver lipogenesis and lipid peroxidation, adipose lipolysis, and intestinal lipid absorption in high-fat (HF) diet-fed rats for 12 weeks. Rats were divided into four groups: normal control diet (NC), HF diet, HF diet+5% HC, and HF diet+5% CO. Both HC and CO supplementation could reduce liver lipid biosynthesis, but HC had a better effect than CO on improving liver lipid accumulation in HF diet-fed rats. The increased levels of triglyceride decreased lipolysis rate, and increased lipoprotein lipase activity in the perirenal adipose tissue of HF diet-fed rats could be significantly reversed by both HC and CO supplementation. HC, but not CO, supplementation promoted liver antioxidant enzymes glutathione peroxidase and superoxide dismutase activities and reduced liver lipid peroxidation. In the intestines, CO, but not HC, supplementation reduced lipid absorption by reducing the expression of fabp2 and fatp4 mRNA. These results suggest that HC and CO have different mechanisms for improving lipid metabolism in HF diet-fed rats.

Low-Molecular-Weight Chitosan Attenuates Lipopolysaccharide-Induced Inflammation in IPEC-J2 Cells by Inhibiting the Nuclear Factor-κB Signalling Pathway

Low-molecular-weight chitosan (LMWC), a product of chitosan deacetylation, possesses anti-inflammatory effects. In the present study, a porcine small intestinal epithelial cell line, IPEC-J2, was used to assess the protective effects of LMWC on lipopolysaccharide (LPS)-induced intestinal epithelial cell injury. IPEC-J2 cells were pretreated with or without LMWC (400 μg/mL) in the presence or absence of LPS (5 μg/mL) for 6 h. LMWC pretreatment increased (p < 0.05) the occludin abundance and decreased (p < 0.05) the tumour necrosis factor-α (TNF-α) production, apoptosis rate and cleaved cysteinyl aspartate-specific protease-3 (caspase-3) and -8 contents in LPS-treated IPEC-J2 cells. Moreover, LMWC pretreatment downregulated (p < 0.05) the expression levels of TNF receptor 1 (TNFR1) and TNFR-associated death domain and decreased (p < 0.05) the nuclear and cytoplasmic abundance of nuclear factor-κB (NF-κB) p65 in LPS-stimulated IPEC-J2 cells. These results suggest that LMWC exerts a mitigation effect on LPS-induced intestinal epithelial cell damage by suppressing TNFR1-mediated apoptosis and decreasing the production of proinflammatory cytokines via the inhibition of NF-κB signalling pathway.

Efficacy of epicardial implantation of acellular chitosan hydrogels in ischemic and nonischemic heart failure: impact of the acetylation degree of chitosan

This work explores the epicardial implantation of acellular chitosan hydrogels in two murine models of cardiomyopathy, focusing on their potential to restore the functional capacity of the heart. Different chitosan hydrogels were generated using polymers of four degrees of acetylation, ranging from 2.5% to 38%, because the degree of acetylation affects their degradation and biological activity. The hydrogels were adjusted to a 3% final polymer concentration. After complete macromolecular characterization of the chitosans and study of the mechanical properties of the resulting hydrogels, they were sutured onto the surface of the myocardium, first in rat after four-weeks of coronary ligation (n=58) then in mice with cardiomyopathy induced by a cardiac-specific invalidation of serum response factor (n=20). The implantation of the hydrogels was associated with a reversion of cardiac function loss with maximal effects for the acetylation degree of 24%. The extent of fibrosis, the cardiomyocyte length-to-width ratio, as well as the genes involved in fibrosis and stress were repressed after implantation. Our study demonstrated the beneficial effects of chitosan hydrogels, particularly with polymers of high degrees of acetylation, on cardiac remodeling in two cardiomyopathy models. Our findings indicate they have great potential as a reliable therapeutic approach to heart failure.

Research Advances in Chitosan Oligosaccharides: From Multiple Biological Activities to Clinical Applications

Chitosan oligosaccharides (COS), hydrolysed products of chitosan, are low-molecular weight polymers with a positive charge and good biocompatibility. COS have recently been reported to possess various biological activities, including hypoglycaemic, hypolipidaemic, antioxidantantioxidant, immune regulation, anti-inflammatory, antitumour, antibacterial, and tissue engineering activities, exhibiting extensive application prospects. Currently, the biological processes and mechanisms of COS are attractive topics of study, ranging from the genetic, molecular and protein levels. This article reviews the recent discoveries about COS, especially in metabolic regulation, immune function and tissue repair, providing important insights into their multiple biological activities, medical benefits, and therapeutic mechanisms.