Activation of PI3K/Akt mediates the protective effect of diallyl trisulfide on doxorubicin induced cardiac apoptosis.

Diallyl trisulfide (DATS), an organosulfide compound derived from garlic, is renowned for its potent antioxidant properties, particularly in countering the generation of reactive oxygen species (ROS). It has also gained recognition as a potential agent for preventing heart-related conditions. Doxorubicin (Dox), a commonly used chemotherapeutic drug, is known to induce severe cardiac complications by promoting ROS production. Therefore, it was imperative to investigate whether DATS possesses cardioprotective capabilities against Dox-induced cardiac apoptosis and elucidate the underlying mechanisms. In this study, we observed that the intracellular ROS levels and cardiac apoptosis were heightened in H9c2 cells exposed to Dox (1 µM). However, treatment with 10 µM DATS effectively mitigated the Dox-induced ROS generation and apoptotic signaling, concurrently activating the PI3K/Akt pathway. Notably, the anti-apoptotic effects of DATS were attenuated when PI3K siRNA and the LY294002 PI3K inhibitor were employed. Furthermore, the TUNEL assay results demonstrated a significant reduction in Dox-induced apoptosis with DATS treatment. In summary, our findings indicate that DATS can activate the PI3K/Akt pathway, reducing ROS production in cardiac cells exposed to Dox, and subsequently rescue cardiac cells from apoptosis.

Impact of Type 1 Versus Type 2 Diabetes on Developing Herpes Zoster and Post-herpetic Neuralgia: A Population-based Cohort Study.

Type 2 diabetes is associated with an increased risk of herpes zoster and postherpetic neuralgia. However, the association of type 1 diabetes with herpes zoster or postherpetic neuralgia remains unclear. This retrospective cohort study using Taiwan's Health Insurance Research Database included 199,566 patients with type 1 diabetes and 1,458,331 with type 2 diabetes, identified during the period 2000 to 2012. Patients with type 1 diabetes had a significantly higher risk of developing herpes zoster than those with type 2 diabetes (p < 0.001). Across all age groups, the impact of diabetes on herpes zoster was greater in type 1 than in type 2 diabetes. Patients with both type 1 and type 2 diabetes had a 1.45-fold higher risk of post-herpetic neuralgia than those without diabetes (hazard ratio 1.45, 95% confidence interval 1.28-1.65; hazard ratio 1.45, 95% confidence interval 1.37-1.52, respectively), and there was no difference between the 2 types of diabetes (hazard ratio 1.06; 95% confidence interval 0.93-1.21). The results recommend consideration of herpes zoster vaccination at an earlier age in patients with type 1 diabetes.

Phloem unloading in cultivated melon fruits follows an apoplasmic pathway during enlargement and ripening.

Melon (Cucumis melo L.) has a long history of cultivation worldwide. During cultivation, domestication, and selection breeding, the sugar content of mature melon fruits has been significantly increased. Compared with unsweet melon and wild melon, rapid sucrose accumulation can occur in the middle and late stages of sweet melon fruit development. The phloem unloading pathway during the evolution and development of melon fruit has not been identified and analyzed. In this study, the phloem unloading pathway and the function of related sugar transporters in cultivated and wild melon fruits were analyzed by CFDA [5(6)-carbofluorescein diacetate] and esculin tracing, cytological pathway observation, qRT-PCR, and gene function analysis, etc. Results show that the phloem unloading pathway of wild melon fruit is largely symplastic, whereas the phloem unloading pathway of cultivated melon fruit shifts from symplastic to apoplasmic during development. According to a fruit grafting experiment, the fruit sink accumulates sugars independently. Correlation analysis showed that the expression amounts of several sucrose transporter genes were positively correlated with the sucrose content of melon fruit. Furthermore, CmSWEET10 was proved to be a sucrose transporter located on the plasma membrane of the phloem and highly expressed in the premature stage of sweet melon fruits, which means it may be involved in phloem apoplast unloading and sucrose accumulation in sweet melon fruits. Finally, we summarize a functional model of related enzymes and sugar transporters involved in the apoplast unloading of sweet melon fruits during enlargement and sucrose accumulation.

Paeoniflorin found in Paeonia lactiflora root extract inhibits melanogenesis by regulating melanin-related signal transduction in B16F10 cells.

BACKGROUND: Skin pigmentation is modulated by various processes, with melanogenesis playing a key role. Melanin is synthesized by the catalysis of melanogenesis-related enzymes, such as tyrosinase and tyrosine-related proteins TRP-1 and TRP-2. Paeoniflorin is the main bioactive component of Paeonia suffruticosa Andr., Paeonia lactiflora., or Paeonia veitchii Lynch and has been used for centuries for its anti-inflammatory, anti-oxidant, and anti-carcinogenic properties. AIMS & METHODS: In this study, melanin biosynthesis in mouse melanoma (B16F10) cells was induced using α-melanocyte-stimulating hormone (α-MSH), and then cells were co-treated with paeoniflorin to evaluate its potential anti-melanogenic effect. RESULTS: α-MSH stimulation increased melanin content, tyrosinase activity, and melanogenesis-related markers in a dose-dependent manner. However, treatment with paeoniflorin reversed α-MSH-induced upregulation of melanin content and tyrosinase activity. Furthermore, paeoniflorin inhibited cAMP response element-binding protein activation and TRP-1, TRP-2, and microphthalmia-associated transcription factor protein expression in α-MSH-stimulated B16F10 cells. CONCLUSION: Overall, these findings show the potential of paeoniflorin as a depigmenting agent for cosmetic products.

Doxorubicin induced ROS-dependent HIF1α activation mediates blockage of IGF1R survival signaling by IGFBP3 promotes cardiac apoptosis.

Doxorubicin (Dox) causes the generation of intracellular reactive oxygen species (ROS) and inactivates insulin-like growth factor 1 (IGF1) signaling, leading to cardiomyocyte apoptosis. IGF-binding protein 3 (IGFBP3) is the most abundant circulating IGF1 carrier protein with high affinity, which has been reported to mediate ROS-induced apoptosis. Hypoxia-inducible factor 1α (HIF1A), an upstream protein of IGFBP3 is regulated by prolyl hydroxylase domain (PHD) through hydroxylation. In this study, we investigated the role of IGFBP3, HIF1A, and PHD in Dox-induced cardiac apoptosis.Cells challenged with 1 µM Dox for 24 h increased ROS generation, augmented intracellular and secreted IGFBP3 levels, and reduced IGF1 signaling. Further, we showed that Dox enhanced the extracellular association of IGF1 with IGFBP3. Moreover, echocardiography parameters, especially ejection fraction (EF) and fractional shortening (FS) were significantly reduced in ventricle tissue of Dox challenged rats. Notably, siRNA approach against IGFBP3 or an anti-IGFBP3 antibody rescued Dox-induced cardiac apoptosis, mitochondrial ROS, and the decrease in the IGF1 signaling activity. Furthermore, silencing HIF1A either using siRNA or inhibitor downregulated intracellular IGFBP3, rescued apoptosis, mitochondrial generation, and reduction in IGF1 signaling. Finally, western blot data revealed that ROS scavenger reversed Dox-induced cardiac apoptosis, increased levels of HIF1A and secreted IGFBP3, and decreased IGF1 survival signaling and PHD expression.These findings suggest that Dox-induced ROS generation suppressed PHD, which might stabilize nuclear HIF1A protein, leading to increased IGFBP3 expression and secretion. This in turn results in enhanced extracellular association of the latter with IGF1 and blocks IGF1 pro-survival signaling and may result in inducing cardiac apoptosis.

Reversion of glucocorticoid-induced senescence and collagen synthesis decrease by LY294002 is mediated through p38 in skin.

Glucocorticoids (GCs) are the most common treatment for inflammatory skin disorders; however, they show several adverse side effects, including atrophy and collagen decrease following chronic treatment. In particular, transcription factors and p38 signaling for collagen synthesis have been shown to be suppressed by the active glucocorticoid receptor (GR). LY294002 (LY), a phosphoinositide 3-kinase (PI3K) inhibitor, has been reported to protect keratinocytes in epidermis against GC-induced hypoplasia; however, its protective effect in dermis remains unclear. Furthermore, clobetasol propionate (CP) is the most used commercial synthetic GC, yet studies on how CP causes side effects in dermal fibroblasts are limited. In this study, dermal atrophy was modeled using CP in human dermal fibroblasts (HDFs) and C57BL/6 mice. CP treatment significantly upregulated FK506 binding protein 5 (FKBP51), an atrophy marker (2.4 ± 0.25 and 3.3 ± 0.3 fold in in vitro and in vivo, respectively), phosphorylated GR (1.96 ± 0.08 and 2.29 ± 0.25 fold in in vitro and in vivo, respectively), decreased fibroblast proliferation (82.71 ± 1.95% in in vitro), reduced collagen synthesis (0.36 ± 0.05 and 0.3 ± 0.1 fold in in vitro and in vivo, respectively), and induced aging, all of which were reversed by LY treatment (from 1.43 ± 0.08 to 2.8 ± 0.12 fold) without showing growth inhibition and exerting the anti-inflammation of CP. Interestingly, the protective effect of LY was dose-dependently reversed by treatment with a p38 inhibitor and reached 2.9 ± 0.15 fold at dose 20 µM. Taken together, our results demonstrate that LY reduced CP-induced upregulation of the atrophy marker FKBP51, GR phosphorylation, and GR nuclear translocation via the activation of p38, whilst maintaining the anti-inflammatory effect of glucocorticoids.

Comparative analysis of pumpkin rootstocks mediated impact on melon sensory fruit quality through integration of non-targeted metabolomics and sensory evaluation.

Melon fruits are popular because of sweet taste and pleasant aroma. Grafting has been extensively used for melons to alleviate abiotic stresses and control soil borne diseases. However, use of grafting for vegetable fruit quality improvement is less studies. In modern age fruit quality particularly sensory quality characteristics have key importance from consumer eye lens. We performed liquid chromatography-mass spectrometry and metabonomic analysis to examine sensory fruit quality of melon grafted onto ten different pumpkin rootstocks. Bases on the result of our study, 478 metabolites were detected and 184 metabolites consisting of lipids, amino acids and organic oxygen compounds were differentially expressed in grafted melon fruits. The results from metabolomic, physiochemical and sensory analysis explain the differences in melon fruit flavor from two contrasting rootstocks. In conclusion the fruits from Tianzhen No. 1 rootstock exhibited better organoleptic characteristics and higher soluble sugars content [glucose (19.87 mg/g), fructose (19.68 mg/g) and sucrose (169.45 mg/g)] compared with other rootstocks used in this study. Moreover, the contents of bitterness causing amino acids such as L-arginine, L-asparagine, Histidinyl-histidine and Acetyl-DL-valine were found lower in Tianzhen No. 1-grafted melon fruits compared with Sizhuang No. 12-grafted melon fruits. These fruit quality characteristics made Tianzhen No. 1 rootstock suitable for commercial cultivation of Yuniang melon.

Contributions of sugar transporters to crop yield and fruit quality.

The flux, distribution, and storage of soluble sugars regulate crop yield in terms of starch, oil, protein, and total carbohydrates, and affect the quality of many horticultural products. Sugar transporters contribute to phloem loading and unloading. The mechanisms of phloem loading have been studied in detail, but the complex and diverse mechanisms of phloem unloading and sugar storage in sink organs are less explored. Unloading and subsequent transport mechanisms for carbohydrates vary in different sink organs. Analyzing the transport and storage mechanisms of carbohydrates in important storage organs, such as cereal seeds, fruits, or stems of sugarcane, will provide information for genetic improvements to increase crop yield and fruit quality. This review discusses current research progress on sugar transporters involved in carbohydrate unloading and storage in sink organs. The roles of sugar transporters in crop yield and the accumulation of sugars are also discussed to highlight their contribution to efficient breeding.

Seven traditional Chinese herbal extracts fermented by Lactobacillus rhamnosus provide anti-pigmentation effects by regulating the CREB/MITF/tyrosinase pathway.

Skin pigmentation is resulted from several processes, such as melanin synthesis transportation and abnormal melanin accumulation in keratinocytes. Various studies have suggested that seven traditional Chinese herbal extracts from Atractylodes macrocephala, Paeonia lactiflora, Bletilla striata, Poria cocos, Dictamnus dasycarpus, Ampelopsis japonica and Tribulus terrestris (which we collectively named ChiBai), show several protective effects toward skin-related diseases. Lactobacillus rhamnosus, a lactic acid bacterium, has been reported to treat skin inflammation and atopic dermatitis. In this study, the broth produced by the cofermentation of ChiBai with Lactobacillus rhamnosus was studied for its effects on skin pigmentation through in vitro and in vitro experiments. In the in vitro experiments, we found that the fermented broth of ChiBai (FB-ChiBai) suppressed alpha-melanocyte stimulating hormone (α-MSH)-induced melanogenesis in B16F0 murine melanoma cells without any cytotoxicity at a concentration of 0.5%. FB-ChiBai significantly attenuated melanin production, tyrosinase activities and melanogenesis-related signaling pathways. Treatment with FB-ChiBai also reduced the nuclear translocation and promoter binding activities of MITF. In the in vivo experiments, FB-ChiBai was topically applied to the dorsal skin of C57BL/6J nude mice and concurrently irradiated with UVB, three times a week for 8 weeks. The results indicated that FB-ChiBai alleviated UVB-induced hyperpigmentation by reducing epidermal hyperplasia and inhibiting the CREB/MITF/tyrosinase pathway. In conclusion, our data indicated that the anti-melanogenic effects of FB-ChiBai are mediated by the inhibition of CREB/MITF/tyrosinase signaling pathway. The findings suggest that FB-ChiBai can protect against UV-B irradiation and that it might be used as an agent in cosmetic products to protect against UVB-induced hyperpigmentation.

Extracts of Jasminum sambac flowers fermented by Lactobacillus rhamnosus inhibit H2 O2 - and UVB-induced aging in human dermal fibroblasts.

Ultraviolet (UV) irradiation is a crucial factor that leads to skin photoaging and results in increased DNA damage, oxidative stress, and collagen degradation. Jasmine flowers have been utilized as a traditional medicine in Asia to treat various diseases, including dermatitis, diarrhea, and fever. Furthermore, the fermented broth of Lactobacillus rhamnosus has been reported to exert protective effects on the skin. In the present study, jasmine flower extract was fermented with L. rhamnosus. We investigated the antioxidant and collagen-promoting effects on UVB/H2 O2 -induced HS68 dermal fibroblast cell damage. The results indicated that treatment with the fermented flower extracts of Jasminum sambac (F-FEJS) could enhance the viability of HS68 cells. Furthermore, the UVB/H2 O2 -induced excessive production of reactive oxygen species, degradation of collagen, activation of MAPKs, including P38, ERK, and JNK, and premature senescence were remarkably attenuated by F-FEJS in dermal fibroblast cells. The nuclear accumulation of p-c-jun, which is downstream of MAPK, and the inactivation of p-smad2/3, which is one of the crucial transcription factors that enhance collagen synthesis, were reversed in response to F-FEJS treatment in UVB/H2 O2 -exposed cells. Notably, the expression of antioxidant genes, such as HO-1, and the nuclear translocation of Nrf2 were further enhanced by F-FEJS in UVB/H2 O2 -treated cells. Interestingly, the F-FEJS-induced increase in ARE luciferase activity indicated the activation of Nrf2/ARE signaling. In conclusion, our findings demonstrated that F-FEJS can effectively ameliorate UVB/H2 O2 -induced dermal cell aging and may be considered a promising ingredient in skin aging therapy.

Signal transducer and activator of transcription 3 mediates apoptosis inhibition through reducing mitochondrial ROS and activating Bcl-2 in gemcitabine-resistant lung cancer A549 cells.

Lung cancer is a leading cause of cancer-related death worldwide. In this study, we used lung adenocarcinoma cells as a model, as lung adenocarcinoma has the highest mortality rate among all lung cancers. For the past few years, medical treatments or lung cancer have been limited because of chemotherapy resistance. Therefore, understanding the pathogenesis of the development of drug resistance in lung cancer is urgent. Gemcitabine is widely prescribed in the chemotherapeutic treatment of lung cancers. In this study, we developed gemcitabine-resistant lung adenocarcinoma cells (A549-GR) from the A549 cell line. The results showed that apoptotic protein expression and reactive oxygen species (ROS) generation were reduced in A549-GR cells compared to A549 cells. Interestingly, we found that signal transducer and activator of transcription 3 (STAT3) translocated to the nucleus and mitochondria to affect the apoptotic pathway and ROS generation, respectively. Furthermore, treatment with STAT3 small interfering RNA diminished the increase in ROS production, proliferation and antiapoptotic proteins in A549-GR cells. Taken together, the study demonstrated that STAT3 acts as an essential regulator and moderates apoptosis through two major mechanisms to induce gemcitabine resistance in cells; and these findings provide a potential target for the treatment of gemcitabine-resistant lung cancer.

Overexpression of Melon Tonoplast Sugar Transporter CmTST1 Improved Root Growth under High Sugar Content.

Sugar allocation is based on the source-to-sink and intracellular transport between different organelles, and sugar transporters are usually involved in these processes. Tonoplast sugar transporters (TST) are responsible for transporting sugar into vacuoles; however, the role of TSTs in root growth and the response to abiotic stress is poorly studied. Here, RNA analysis and promoter-ß-glucuronidase staining revealed that a melon TST1 gene (CmTST1) is highly expressed in the roots. The sugar feeding experiment results showed that the expression of CmTST1 in the roots was induced by a relatively high level of sucrose (6%), glucose (3%), and fructose (3%). The ectopic overexpression of CmTST1 in Arabidopsis improved the root and shoot growth of seedlings under high exogenous sugar stress. Furthermore, the ectopic expression of CmTST1 promoted the expression of plasma membrane-located sugar transporters. We proposed that CmTST1 plays a key role in importing sugar transport into the vacuoles of roots in response to metabolic demands to maintain cytosolic sugar homeostasis.

Protective effects of galangin against H2 O2 -induced aging via the IGF-1 signaling pathway in human dermal fibroblasts.

Galangin, a natural flavonol, has anti-inflammatory and antioxidative potential. However, the cytoprotective effects of galangin against oxidative-induced aging in human fibroblasts have not been well studied. IGF-1 signaling pathway is associated with the control of aging and longevity in human. The goal of this study was to investigate the effects of galangin on human skin fibroblast HS68 cells under H2 O2 exposure to induce aging. In this study, we demonstrate that galangin could decrease the levels of pro-inflammatory proteins and enhanced collagen formation through promoting the IGF-1R pathway. Furthermore, aging markers such as senescence-associated ß-galactosidase p53, p21Cip1/WAF1 , and p16INK4A were upregulated under H2 O2 exposure and galangin could reverse its effects. Taken together, these data indicated that anti-inflammatory and antiaging activities of galangin may be mediated through the IGF-1R signaling pathway. These findings may provide the evidence for galangin to develop as an antiwrinkle product on human skin.

Overexpression of hexose transporter CsHT3 increases cellulose content in cucumber fruit peduncle.

Hexose transporters play many important roles in plant development. However, the role of hexose transporter in secondary cell wall growth has not been reported before. Here, we report that the hexose transporter gene CsHT3 is mainly expressed in cells with secondary cell walls in cucumber. Spatiotemporal expression analysis revealed that the transcript of CsHT3 mainly accumulates in the stem, petiole, tendril, and peduncle, all of which contain high cellulose levels. Immunolocalization results show that CsHT3 is localized at the sclereids in young peduncles, shifts to the phloem fiber cells during peduncle development, and then shifts again to the companion cells when the development of secondary cell walls is almost completed. Carboxyfluoresce unloading experiment indicated that carbohydrate unloading in the phloem follows an apoplastic pathway. Overexpression of CsHT3 in cucumber plant can improve the cellulose content and cell wall thickness of phloem fiber cells in the peduncle. The expression of cellulose synthase genes were increased in the CsHT3 overexpression plants. These results indicated that CsHT3 may play an important role in cellulose synthesis through promoting the expression of cellulose synthase genes.

Roles of p38α and p38ß mitogen­activated protein kinase isoforms in human malignant melanoma A375 cells.

Skin cancer is one of the most common cancers worldwide. Melanoma accounts for ~5% of skin cancers but causes the large majority of skin cancer­related deaths. Recent discoveries have shown that the mitogen­activated protein kinase (MAPK) signaling pathway is critical for melanoma development and progression. Many oncogenic pathways that cause melanoma tumorigenesis have been identified, most of which are due to RAF/MEK/ERK (MAPK) pathway activation. However, the precise role of p38 remains unclear. Using specific short hairpin (sh) RNA to silence p38α and p38ß, the present findings demonstrated that p38α was a crucial factor in regulating cell migration in the A375 melanoma cell line. Silencing p38α downregulated the expression of epithelial­mesenchymal transition markers, such as matrix metallopeptidase (MMP) 2, MMP9, twist family bHLH transcription factor 1, snail family transcriptional repressor 1 and vimentin, while mesenchymal­epithelial transition markers, such as E­cadherin, were upregulated. Of note, the results also demonstrated that p38α silencing impaired vascular endothelial growth factor expression, which regulates tumor angiogenesis. Furthermore, p38α knockdown inhibited cell proliferation in melanoma cells. In addition, silencing p38α induced senescence­like features, but not cell cycle arrest. Expression of the senescence markers p16, p21, p53 and ß­galactosidase was upregulated, and an increase in the number of senescence­associated ß­galactosidase­positive cells was observed in a p38α knockdown stable clone. However, no significant difference was found between control and p38ß stable knockdown cells. Taken together, the present results suggested that p38α knockdown impaired migration and proliferation, and increased senescence, in A375 melanoma cells. However, p38ß may not be involved in melanoma tumorigenesis. Therefore, targeting p38α may be a valuable approach towards inhibiting tumor growth and metastasis in patients with melanoma.

ROS- and HIF1α-dependent IGFBP3 upregulation blocks IGF1 survival signaling and thereby mediates high-glucose-induced cardiomyocyte apoptosis.

The prevalence of chronic hyperglycemia and its complications, imposing a critical burden on the worldwide economy and the global healthcare system, is a pressing issue. Mounting evidence indicates that oxidative stress and hypoxia, two noticeable features of hyperglycemia, play a joint crucial role in mediating cellular apoptosis. However, the underlying detailed molecular mechanism remains elusive. Triggered by the observation that insulin-like growth factor (IGF1)-binding protein 3 (IGFBP3) can mediate, in renal cells, high-glucose-induced apoptosis by elevating oxidative stress, we wish to, in this study, know whether or not the similar scenario holds in cardiac cells and, if so, to find its relevant molecular key players, thereby dissecting the underlying molecular pathway. Specifically, we used a combination of three different cellular sources (H9c2 cells, diabetic rats, and neonatal rat ventricular cardiomyocytes) as our model systems of study. We made use of Co-IP assay and western blot analysis in conjunction with loss-of-function reasoning, gain-of-function logic, and inhibitor treatment as our main analytical tools. As a result, briefly, our main findings are that hyperglycemia can induce cardiac IGFBP3 overexpression and secretion, that high levels of IGFBP3 can sequester IGF1 from IGF1 survival pathway, leading to apoptosis, and that IGFBP3 gene upregulation is hypoxia-inducible factor (HIF)1α-dependent and reactive oxygen species dependent. Piecing these findings together allows us to propose the improved molecular regulatory mechanism. In conclusion, we have established the molecular roles of IGFBP3, HIF1, and prolyl hydroxylase domain in connecting oxidative stress with hypoxia and in cellular apoptosis under hyperglycemia.

Overexpression of the tonoplast sugar transporter CmTST2 in melon fruit increases sugar accumulation.

Fruits are an important part of the human diet and sugar content is a major criterion used to evaluate fruit quality. Melon fruit accumulate high sugar concentrations during their development; however, the mechanism through which these sugars are transported into the vacuoles of fruit cells for storage remains unclear. In this study, three tonoplast sugar transporters (TSTs), CmTST1, CmTST2, and CmTST3, were isolated from melon plants. Analysis of subcellular localization revealed that all these proteins were targeted to the tonoplast, and evaluation of spatial expression and promoter-GUS activity indicated that they had different expression patterns in the plant. RT-PCR and qRT-PCR results indicated that CmTST2 exhibited the highest expression level among the TST isoforms during melon fruit development. Histochemical and immunohistochemistry localization experiments were performed to identify the tissue- and cell-type localization of CmTST2 in the fruit, and the results indicated that both its transcription and translation were in the mesocarp and vascular cells. Overexpressing the CmTST2 gene in strawberry fruit and cucumber plants by transient expression and stable transformation, respectively, both increased sucrose, fructose, and glucose accumulation in the fruit. The results indicate that CmTST2 plays an important role in sugar accumulation in melon fruit.

Acute hypoxic preconditioning prevents palmitic acid-induced cardiomyocyte apoptosis via switching metabolic GLUT4-glucose pathway back to CD36-fatty acid dependent.

Metabolic syndrome is a risk factor for the development of cardiovascular diseases. Myocardial cell damage leads to an imbalance of energy metabolism, and many studies have indicated that short-term hypoxia during myocardial cell injury has a protective effect. In our previous animal studies, we found that short-term hypoxia in the heart has a protective effect, but long-term hypoxia increases myocardial cell injury. Palmitic acid (PA)-treated H9c2 cardiomyoblasts and neonatal rat ventricle cardiomyocytes were used to simulate hyperlipidemia model, which suppress cluster of differentiation 36 (CD36) and activate glucose transporter type 4 (GLUT4). We exposed the cells to short- and long-term hypoxia and investigated the protective effects of hypoxic preconditioning on PA-induced lipotoxicity in H9c2 cardiomyoblasts and neonatal rat cardiomyocytes. Preconditioning with short-term hypoxia enhanced both CD36 and GLUT4 metabolism pathway protein levels. Expression levels of phospho-PI3K, phospho-Akt, phospho-AMPK, SIRT1, PGC1α, PPARα, CD36, and CPT1ß induced by PA was reversed by short-term hypoxia in a time-dependent manner. PA-induced increased GLUT4 membrane protein level was reduced in the cells exposed to short-term hypoxia and si-PKCζ. Short-term hypoxia, resveratrol and si-PKCζ rescue H9c2 cells from apoptosis induced by PA and switch the metabolic pathway from GLUT4 dependent to CD36 dependent. We demonstrate short-term hypoxic preconditioning as a more efficient way as resveratrol in maintaining the energy metabolism of hearts during hyperlipidemia and can be used as a therapeutic strategy.

Diallyl trisulfide suppresses doxorubicin-induced cardiomyocyte apoptosis by inhibiting MAPK/NF-κB signaling through attenuation of ROS generation.

BACKGROUND: Doxorubicin (Dox) is an effective anticancer agent. However, its effectiveness is limited by its cardiotoxic effects. It has also been reported that the mitogen-activated protein kinase family and NF-κB can be activated by Dox treatment. DATS has been shown to be a potent antioxidant with cardioprotective effects. We investigate whether Dox induces cardiac apoptosis through JNK- and ERK-dependent NF-κB upregulation that can be reduced by DATS treatment. METHODS AND MATERIAL: H9c2 cells were treated with 0.5-1.5 µM Dox for 24 hours. Dox promoted apoptosis and ROS generation and inhibited viability in a dose-dependent manner. Then, the phosphorylation levels of JNK, ERK, and NF-κB evaluated by western blot were elevated. We used inhibitors of JNK, ERK, and NF-κB to determine which of these proteins were involved in Dox-induced apoptosis. Furthermore, Dox-exposed cells were treated with DATS at doses of 1, 5, and 10 µM, and the data demonstrated that ROS generation and apoptotic proteins were decreased and that ERK and NF-κB were downregulated in a dose-dependent manner. Additionally, six-week-old rats were divided into three groups (n = 6 per group) designed as an eight-week study. Normal, Dox (at dose 3.75 mg/kg by ip) administered with or without DATS (at dose 40 mg/kg by gavage) treatment groups. The results indicate that cardiac dysfunction, apoptosis, and JNK, ERK, and NF-κB activation by Dox were reversed by treatment with DATS. CONCLUSION: DATS appears to suppress Dox-induced cardiomyocyte apoptosis by inhibiting NADPH oxidase-related ROS production and the downstream JNK/ERK/NF-κB signaling pathway; DATS may possess clinical therapeutic potential by blocking Dox-induced cardiotoxicity.