Attenuation of inflammatory response by a novel chalcone protects kidney and heart from hyperglycemia-induced injuries in type 1 diabetic mice

Evidence that a Novel Chalcone Derivative, Compound 27, Acts on the Epithelium Via the PI3K/AKT/Nrf2-Keap1 Signaling Pathway, to Mitigate LPS-Induced Acute Lung Injury in Mice

Acute lung injury (ALI) is a highly heterogeneous clinical syndrome and an important cause of mortality in critically ill patients, with limited treatment options currently available. Chalcone, an essential secondary metabolite found in edible or medicinal plants, exhibits good antioxidant activity and simple structure for easy synthesis. In our study, we synthesized a novel chalcone derivative, compound 27 (C27). We hypothesized that C27 could be a potential treatment for acute respiratory distress syndrome (ARDS). Therefore, the protective effects of C27 on lung epithelial cells during ALI and the underlying molecular mechanisms were investigated. In vivo, Intratracheal instillation of LPS (10 mg/kg) was used to induce acute lung injury in mice. In vitro, the bronchial epithelial cell line (Beas-2b) was treated with 30 μM tert-butyl hydroperoxide (t-BHP) to simulate oxidative stress. Our findings demonstrate that pretreatment with C27 reduces LPS-induced oxidative destruction and cellular apoptosis in lung tissues of mice. Furthermore, it significantly attenuates t-BHP-induced cellular reactive oxygen species (ROS) generation, mitochondrial damage, and apoptosis in vitro. Mechanistically, the signaling pathway involving Nrf2-Keap1 and the downstream antioxidative proteins were activated by C27 in vivo. Additionally, PI3K inhibitor LY294002 and Nrf2 inhibitor ML385 abolished the effect of C27 in vitro, indicating that the protective effect of C27 is mediated via the PI3K/AKT/Nrf2-Keap1 pathway. Our study provides evidence that C27 protects against LPS-induced ALI by mitigating oxidative stress via activation of the PI3K/AKT/Nrf2-Keap1 signaling pathway. Therefore, we hypothesize that C27 represents a viable alternative for ALI therapy.

The mechanisms and therapeutic potential of clopidogrel in mitigating diabetic cardiomyopathy in db/db mice

Clopidogrel has been shown to play a protective role against diabetic nephropathy. However, whether clopidogrel exerts a protective effect against diabetic cardiomyopathy (DCM) is unknown. Three-month-old male db/db mice were administered clopidogrel daily at doses of 5, 10, and 20 mg/kg by gavage for 5 months. Here, we showed that clopidogrel effectively attenuated diabetes-induced cardiac hypertrophy and cardiac dysfunction by inhibiting cardiac fibrosis, inflammatory responses, and oxidative stress damage in db/db mice. Diabetes-induced cardiac fibrosis was inhibited by clopidogrel treatment via blockade of the TGF-β1/Smad3/P2RY12 pathway and inhibition of macrophage infiltration in db/db mice. The protective effects of clopidogrel against oxidative damage were mediated by the induction of the Nrf2 signaling pathway. Taken together, our findings provide strong evidence that clopidogrel is a promising effective agent for the treatment of DCM by alleviating diabetes-induced cardiac hypertrophy and dysfunction. P2RY12 might be an effective target for the treatment of DCM.

Type 1 diabetes, its complications, and non-ischemic cardiomyopathy: a mendelian randomization study of European ancestry

BACKGROUND

Type 1 diabetes (T1D) is a significant risk factor for a range of cardiovascular diseases. Nonetheless, the causal relationship between T1D and non-ischemic cardiomyopathy (NICM) remains to be elucidated. Furthermore, the mechanisms responsible for the progression from T1D to NICM have not been definitively characterized.

OBJECTIVE

The aim of this study was to conduct a Mendelian randomization (MR) study to investigate the causal effects of T1D and its complications on the development of NICM. Additionally, this study aimed to conduct a mediation analysis to identify potential mediators within this correlation.

METHODS

Genetic variants were used as instrumental variables for T1D. The summary data for T1D were obtained from two genome-wide association study datasets. The summary data for T1D with complications and NICM were obtained from the Finnish database. Two-sample MR, multivariable MR and mediation MR were conducted in this study.

RESULTS

The study revealed a causal association between T1D, T1D with complications, and NICM (with odds ratios of 1.02, 95% CI 1.01-1.04, p = 1.17e-04 and 1.03, 95% CI 1.01-1.05, p = 3.15e-3). Even after adjusting for confounding factors such as body mass index and hypertension, T1D remained statistically significant (with odds ratio of 1.02, 95% CI 1.01-1.04, p = 1.35e-4). Mediation analysis indicated that monokine induced by gamma interferon may play a mediating role in the pathogenesis of T1D-NICM (mediation effect indicated by odds ratio of 1.005, 95% CI 1.001-1.01, p = 4.9e-2).

CONCLUSION

The study demonstrates a causal relationship between T1D, its complications, and NICM. Additionally, monokine induced by gamma interferon may act as a potential mediator in the pathogenesis of T1D-NICM.

Novel hybrids of quinoline with pyrazolylchalcones as potential antimalarial agents: Synthesis, biological evaluation, molecular docking and ADME prediction

A novel series of pyrazolyl chalcones containing quinoline scaffold, 5 a-v has been synthesized by Claisen Schimdt condensation of aromatic acetophenone with 1-(4-methylquinolin-2-yl)-3-aryl-1H-pyrazole-4-carbaldehyde in quantitative yield. The compounds were characterized using IR, NMR, MS and elemental analysis. An E-configuration about CC ethylenic bond was determined using ¹H NMR spectroscopy. These compounds exhibited significant antimalarial potential against CQ-sensitive and CQ-resistant strain of Plasmodium falciparum. Structure activity relationship has also been established based on outcomes of in vitro schizont inhibition assay. Compound 5u, (Z)-3-(1-(4-methylquinolin-2-yl)-3-p-tolyl-1H-pyrazol-4-yl)-1-p-tolylprop-2-en-1-one, was found to be the most potent among the series of synthetic analogues. In vivo, it demonstrated significant parasitemia suppression of 78.01% at a dose of 200 mg/kg against P. berghei in infected mice without any mortality in 7 days. In silico molecular docking study revealed that this compound 5u bound to the active site of cysteine protease falcipain-2 enzyme. Furthermore, in silico ADME studies, were also performed and physicochemical qualifications of the title compounds were determined. The biological outcomes of newer heterocyclic compounds may pave the new paths for researchers in development of potential antimalarial agents.

Chalcone Derivatives with a High Potential as Multifunctional Antioxidant Neuroprotectors

A systematic, rational search for chalcone derivatives with multifunctional behavior has been carried out, with the support of a computer-assisted protocol (CADMA-Chem). A total of 568 derivatives were constructed by incorporating functional groups into the chalcone structure. Selection scores were calculated from ADME properties, toxicity, and manufacturability descriptors. They were used to select a subset of molecules (23) with the best drug-like behavior. Reactivity indices were calculated for this subset. They were chosen to account for electron and hydrogen atom donating capabilities, which are key processes for antioxidant activity. The indexes showed that four chalcone derivatives (dCHA-279, dCHA-568, dCHA-553, and dCHA-283) are better electron and H donors than the parent molecule and some reference antioxidants (Trolox, ascorbic acid, and α-tocopherol). In addition, based on molecular docking, they are predicted to act as catechol-O-methyltransferase (COMT), acetylcholinesterase (AChE), and monoamine oxidase B (MAO-B) inhibitors. Therefore, these four molecules are proposed as promising candidates to act as multifunctional antioxidants with neuroprotective effects.

Naringenin as a natural immunomodulator against T cell-mediated autoimmune diseases: literature review and network-based pharmacology study

T cells, especially CD4+ T helper (Th) cells, play a vital role in the pathogenesis of specific autoimmune diseases. Naringenin, a citrus flavonoid, exhibits anti-inflammatory, anti-oxidant, and antitumor properties, which have been verified in animal autoimmune disease models. However, naringenin's possible effects and molecular mechanisms in T cell-mediated autoimmune diseases are unclear. This review summarizes the findings of previous studies and predicts the target of naringenin in T cell-mediated autoimmune disorders such as multiple sclerosis, inflammatory bowel disease, and rheumatoid arthritis through network pharmacology analysis. We performed DAVID enrichment analysis, protein-protein interaction analysis, and molecular docking to predict the positive effect of naringenin on T cell-mediated autoimmune disorders. Sixteen common genes were screened, among which the core genes were PTGS2, ESR1, CAT, CASP3, MAPK1, and AKT1. The possible molecular mechanism relates to HIF-1, estrogen, TNF, and NF-κB signaling pathways. Our findings have significance for future naringenin treatment of T cell-mediated autoimmune diseases.

The Cytotoxicity and Nephroprotective Activity of the Ethanol Extracts of Angelica keiskei Koidzumi Stems and Leaves against the NAPQI-Induced Human Embryonic Kidney (HEK293) Cell Line

Materials and Methods

A. keiskei Koidzumi plant was collected from Mount Rinjani, Lombok, Indonesia, and was identified at the School of Biology Sciences and Technology, Bandung Institute of Technology, Indonesia. Extraction of the stems (ASE) and leaves (ALE) was performed by employing ethanol 70% for 3 × 24 h at 26°C. The cytotoxicity study of the extracts was assessed using the water-soluble tetrazolium salt-8 (WST-8) reagent on the HEK293 cell line, while the nephroprotective activity assay was determined on the NAPQI-induced HEK293 cell line.

Results

The WST-8 assay showed that the cytotoxicity IC₅₀ of ASE = 2322 μg/mL and IC₅₀ of ALE = 2283 μg/mL. The nephroprotective activity assay revealed that ASE possesses nephroprotective activity against the NAPQI-induced HEK293 cell line at 1161 μg/mL, while ALE does not show the nephroprotective activity.

Conclusion

Taken together, lower concentrations of ASE and ALE (<2000 μg/mL) are not toxic to the HEK293 cell line, and only ASE indicates the activity to protect the HEK293 cell line against NAPQI damage. This Japanese celery could be further explored for its potential as a plant-based nephroprotective drug.

Isoliquiritigenin attenuates diabetic cardiomyopathy via inhibition of hyperglycemia-induced inflammatory response and oxidative stress

BACKGROUND

Inflammation and oxidative stress play essential roles in the occurrence and progression of diabetic cardiomyopathy (DCM). Isoliquiritigenin (ISL), a natural chalcone, exhibits strong anti-inflammatory and antioxidant activities.

HYPOTHESIS/PURPOSE

In this study, we aimed to investigate the protective effects of ISL on DCM using high glucose (HG)-challenged cultured cardiomyocytes and streptozotocin (STZ)-induced diabetic mice.

STUDY DESIGN AND METHODS

Embryonic rat heart-derived H9c2 cells challenged with a high concentration of glucose were used to evaluate the anti-inflammatory and antioxidant effects of ISL. STZ-induced diabetic mice were used to study the effects of ISL in DCM in vivo. Furthermore, cardiac fibrosis, hypertrophy, and apoptosis were explored both in vitro and in vivo.

RESULTS

ISL effectively inhibited HG-induced hypertrophy, fibrosis, and apoptosis probably by alleviating the inflammatory response and oxidative stress in H9c2 cells. Results from in vivo experiments showed that ISL exhibited anti-inflammatory and antioxidant stress activities that were characterized by the attenuation of cardiac hypertrophy, fibrosis, and apoptosis, which resulted in the maintenance of cardiac function. The protective effects of ISL against inflammation and oxidative stress were mediated by the inhibition of mitogen-activated protein kinases (MAPKs) and induction of nuclear factor-erythroid 2 related factor 2 (Nrf2) signaling pathway, respectively.

CONCLUSION

Our results provided compelling evidence that ISL, by virtue of neutralizing excessive inflammatory response and oxidative stress, could be a promising agent in the treatment of DCM. Targeting the MAPKs and Nrf2 signaling pathway might be an effective therapeutic strategy for the prevention and treatment of DCM.

Role of Flavonoids in The Interactions among Obesity, Inflammation, and Autophagy

Nowadays, obesity is considered as one of the main concerns for public health worldwide, since it encompasses up to 39% of overweight and 13% obese (WHO) adults. It develops because of the imbalance in the energy intake/expenditure ratio, which leads to excess nutrients and results in dysfunction of adipose tissue. The hypertrophy of adipocytes and the nutrients excess trigger the induction of inflammatory signaling through various pathways, among others, an increase in the expression of pro-inflammatory adipocytokines, and stress of the endoplasmic reticulum (ER). A better understanding of obesity and preventing its complications are beneficial for obese patients on two facets: treating obesity, and treating and preventing the pathologies associated with it. Hitherto, therapeutic itineraries in most cases are based on lifestyle modifications, bariatric surgery, and pharmacotherapy despite none of them have achieved optimal results. Therefore, diet can play an important role in the prevention of adiposity, as well as the associated disorders. Recent results have shown that flavonoids intake have an essential role in protecting against oxidative damage phenomena, and presents biochemical and pharmacological functions beneficial to human health. This review summarizes the current knowledge of the anti-inflammatory actions and autophagic flux of natural flavonoids, and their molecular mechanisms for preventing and/or treating obesity.

A chalcone derivative, 1m-6, exhibits atheroprotective effects by increasing cholesterol efflux and reducing inflammation-induced endothelial dysfunction

BACKGROUND AND PURPOSE

Atherosclerosis, resulting from lipid dysregulation and vascular inflammation, causes atherosclerotic cardiovascular disease (ASCVD), which contributes to morbidity and mortality worldwide. Chalcone and its derivatives possess beneficial properties, including anti-inflammatory, antioxidant and antitumour activity with unknown cardioprotective effects. We aimed to develop an effective chalcone derivative with antiatherogenic potential.

EXPERIMENTAL APPROACH

Human THP-1 cells and HUVECs were used as in vitro models. Western blots and real-time PCRs were performed to quantify protein, mRNA and miRNA expressions. The cholesterol efflux capacity was assayed by ³ H labelling of cholesterol. LDL receptor knockout (Ldlr^-/- ) mice fed a high-fat diet were used as an in vivo atherogenesis model. Haematoxylin and eosin and oil red O staining were used to analyse plaque formation.

KEY RESULTS

Using ATP-binding cassette transporter A1 (ABCA1) expression we identified the chalcone derivative, 1m-6, which enhances ABCA1 expression and promotes cholesterol efflux in THP-1 macrophages. Moreover, 1m-6 stabilizes ABCA1 mRNA and suppresses the expression of potential ABCA1-regulating miRNAs through nuclear factor erythroid 2-related factor 2 (Nrf2)/haem oxygenase-1 (HO-1) signalling. Additionally, 1m-6 significantly inhibits TNF-α-induced expression of adhesion molecules, vascular cell adhesion molecule 1 (VCAM-1) and intercellular adhesion molecule 1 (ICAM-1), plus production of proinflammatory cytokines via inhibition of JAK/STAT3 activation and the modulation of Nrf2/HO-1 signalling in HUVECs. In atherosclerosis-prone mice, 1m-6 significantly reduces lipid accumulation and atherosclerotic plaque formation.

CONCLUSION AND IMPLICATIONS

Our study demonstrates that 1m-6 produces promising atheroprotective effects by enhancing cholesterol efflux and suppressing inflammation-induced endothelial dysfunction, which opens a new avenue for treating ASCVD.

LINKED ARTICLES

This article is part of a themed issue on Risk factors, comorbidities, and comedications in cardioprotection. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.23/issuetoc.

Phloretin protects against cardiac damage and remodeling via restoring SIRT1 and anti-inflammatory effects in the streptozotocin-induced diabetic mouse model

Diabetic cardiomyopathy increases the risk of heart failure independent of coronary artery disease and hypertension. Phloretin (PHL) shows anti-inflammatory effects in macrophages. In this study, we explored the protective effects of PHL on high glucose (HG)-induced injury in diabetic cardiomyopathy in vivo and in vitro. Using streptozotocin-induced diabetic mouse model and incubating cardiac cells line under a HG environment, PHL were evaluated of the activities of anti-inflammation and anti-fibrosis. In the study, PHL treatment ameliorated cardiomyocyte inflammation injury, and reduced fibrosis in vivo and in vitro. PHL also improved cardiac biochemical criterions after 8 weeks of induction of diabetes in C57BL/6 mice. Molecular docking results indicated that silent information regulator 2 homolog 1 (SIRT1) bound to PHL directly and that SIRT1 expression was upregulated in the PHL-treated group in HG-induced H9C2 cells. Protective effect of PHL was been eliminated in silence SIRT1 H9C2 cells. Taken together, these results suggested that PHL suppressed HG-induced cardiomyocyte injury via restoring SIRT1 expression.

A novel chalcone derivative exerts anti-inflammatory and anti-oxidant effects after acute lung injury

We explored the effects of compound 33, a synthetic chalcone derivative with antioxidant activity, on lipopolysaccharide (LPS)-induced acute lung injury (ALI). Compound 33, dexamethasone or vehicle was administered intragastrically to mice 6 h before intratracheal instillation of LPS. After 24 h, the effects of compound 33 on alveolar structural damage were evaluated by assessing lung morphology and the wet/dry weight ratio. Protein and proinflammatory cytokine levels and superoxide dismutase activity were also examined in the cell free supernatant of bronchoalveolar lavage fluid. Additionally, we investigated the anti-inflammatory and antioxidant activity of compound 33 in vitro and its effects on the MAPK/NF-κB and Nrf2/HO-1 pathways. Pretreatment with compound 33 prevented LPS-induced structural damage, tissue edema, protein exudation, and overproduction of proinflammatory mediators. The effects of compound 33 were similar to or greater in magnitude than those of the positive control, dexamethasone. Moreover, compound 33 exerted anti-inflammatory and antioxidant effects in vitro by inhibiting the MAPK/NF-κB pathway and activating the Nrf2/HO-1 pathway. Compound 33 may therefore be a promising candidate treatment for ALI.

Blockade of myeloid differentiation 2 attenuates diabetic nephropathy by reducing activation of the renin-angiotensin system in mouse kidneys

BACKGROUND AND PURPOSE

Both innate immunity and the renin-angiotensin system (RAS) play important roles in the pathogenesis of diabetic nephropathy (DN). Myeloid differentiation factor 2 (MD2) is a co-receptor of toll-like receptor 4 (TLR4) in innate immunity. While TLR4 is involved in the development of DN, the role of MD2 in DN has not been characterized. It also remains unclear whether the MD2/TLR4 signalling pathway is associated with RAS activation in diabetes.

EXPERIMENTAL APPROACH

MD2 was blocked using siRNA or the low MW inhibitor, L6H9, in renal proximal tubular cells (NRK-52E cells) exposed to high concentrations of glucose (HG). In vivo, C57BL/6 and MD2^-/- mice were injected with streptozotocin to induce Type 1 diabetes and nephropathy.

KEY RESULTS

Inhibition of MD2 by genetic knockdown or the inhibitor L6H9 suppressed HG-induced expression of ACE and angiotensin receptors and production of angiotensin II in NRK-52E cells, along with decreased fibrosis markers (TGF-β and collagen IV). Inhibition of the MD2/TLR4-MAPKs pathway did not affect HG-induced renin overproduction. In vivo, using the streptozotocin-induced diabetic mice, MD2 was overexpressed in diabetic kidney. MD2 gene knockout or L6H9 attenuated renal fibrosis and dysfunction by suppressing local RAS activation and inflammation.

CONCLUSIONS AND IMPLICATIONS

Hyperglycaemia activated the MD2/TLR4-MAPKs signalling cascade to induce renal RAS activation, leading to renal fibrosis and dysfunction. Pharmacological inhibition of MD2 may be considered as a therapeutic approach to mitigate DN and the low MW inhibitor L6H9 could be a candidate for such therapy.

Flavonoids: Broad Spectrum Agents on Chronic Inflammation

Flavonoids are major plant constituents with numerous biological/pharmacological actions both in vitro and in vivo. Of these actions, their anti-inflammatory action is prominent. They can regulate transcription of many proinflammatory genes such as cyclooxygenase-2/inducible nitric oxide synthase and many cytokines/chemokines. Recent studies have demonstrated that certain flavonoid derivatives can affect pathways of inflammasome activation and autophagy. Certain flavonoids can also accelerate the resolution phase of inflammation, leading to avoiding chronic inflammatory stimuli. All these pharmacological actions with newly emerging activities render flavonoids to be potential therapeutics for chronic inflammatory disorders including arthritic inflammation, meta-inflammation, and inflammaging. Recent findings of flavonoids are summarized and future perspectives are presented in this review.

Deletion of RasGRF1 Attenuated Interstitial Fibrosis in Streptozotocin-Induced Diabetic Cardiomyopathy in Mice through Affecting Inflammation and Oxidative Stress

Background: Diabetic cardiomyopathy (DCM) is characterized by cardiac fibrosis and stiffness, which often develops into heart failure. This study investigated the role of Ras protein-specific guanine nucleotide releasing factor 1 (RasGRF1) in the development of DCM. Methods: Forty-eight mice were divided into four groups (n = 12 per group): Group 1: Wild-type (WT) mice, Group 2: RasGRF1 deficiency (RasGRF1^−/−) mice. Group 3: Streptozotocin (STZ)-induced diabetic WT mice, Group 4: STZ-induced diabetic RasGRF1^−/− mice. Myocardial functions were assessed by cardiac echography. Heart tissues from all of the mice were investigated for cardiac fibrosis, inflammation, and oxidative stress markers. Results: Worse impaired diastolic function with elevation serum interleukin (IL)-6 was found in the diabetic group compared with the non-diabetic groups. Serum IL-6 levels were found to be elevated in the diabetic compared with the non-diabetic groups. However, the diabetic RasGRF1^−/− mice exhibited lower serum IL-6 levels and better diastolic function than the diabetic WT mice. The diabetic RasGRF1^−/− mice were associated with reduced cardiac inflammation, which was shown by lower invading inflammation cells, lower expression of matrix metalloproteinase 9, and less chemokines compared to the diabetic WT mice. Furthermore, less oxidative stress as well as extracellular matrix deposition leading to a reduction in cardiac fibrosis was also found in the diabetic RasGRF1^−/− mice compared with the diabetic WT mice. Conclusion: The deletion of RasGRF1 attenuated myocardial fibrosis and improved cardiac function in diabetic mice through inhibiting inflammation and oxidative stress.

The novel chalcone analog L2H17 protects retinal ganglion cells from oxidative stress-induced apoptosis

Chalcone is a plant metabolite widely found in fruits, vegetables, spices and tea, and has anti-tumor, anti-inflammation, immunomodulation, antibacterial and anti-oxidation activities, as well as many other pharmacological and biological effects. Our team has shown that its analogs have antioxidant activity, and oxidative stress is a pathological hallmark of retinal ischemia/reperfusion injury that can lead to retinal damage and visual loss. This investigation aims to identify a chalcone that protects retinal ganglion cells in vitro from the effects of oxidative stress and examine its mechanism. Rat retinal ganglion cell-5 cells were pretreated with chalcones and then exposed to tert-butyl hydroperoxide that causes oxidative damage. Controls received dimethyl sulfoxide only or tert-butyl hydroperoxide in dimethyl sulfoxide. Only (E)-3,4-dihydroxy-2'-methylether ketone (L2H17), of the five chalcone analogs, markedly increased the survival rate of oxidatively injured RGC-5 cells. Thus, subsequent experiments only analyzed the results of the L2H17 intervention. Cell viability and apoptosis were measured. Intracellular superoxide dismutase and reactive oxygen species levels were used to assess induced oxidative stress. The mechanism of action by L2H17 was explored by measuring the ER stress/UPR pathway and the expression and localization of Nrf2. All results demonstrated that L2H17 could reduce the apoptosis of oxidatively injured cells, inhibit caspase-3 activity, increase Bcl-2 expression, decrease Bad expression, increase the activity of superoxide dismutase, inhibit the production of reactive oxygen species, increase Nrf2 immunoreactivity, and reduce the activating transcription factor 4, phospho-eukaryotic initiation factor 2 and CHOP expression. L2H17 protects retinal ganglion cells induced by oxidative stress by regulating Nrf2, which indicates that it has the potential to become a drug for retinal ischemia/reperfusion.

Mechanistic insights into the augmented effect of bone marrow mesenchymal stem cells and thiazolidinediones in streptozotocin-nicotinamide induced diabetic rats

This study was designed to assess whether the protective effects of bone marrow-derived mesenchymal stem cells (MSCs) against diabetes could be enhanced by pioglitazone (PIO), a PPARγ agonist. Combined MSCs and PIO treatments markedly improved fasting blood glucose, body weight, lipid profile levels, insulin level, insulin resistance, β cell function. Those protective effects also attenuated both pancreatic lesions and fibrosis in diabetic rats and decreased the depletion of pancreatic mediators of glycemic and lipid metabolism including peroxisome proliferator-activated receptor alpha (PPARα), PGC-1α, GLP-1 and IRS-2. Cardiac biogenesis of diabetic groups was also improved with MSCs and/or PIO treatments as reflected by the enhanced up-regulation of the expressions of cardiac IRS1, Glucose transporter 4, PGC-1, PPARα and CPT-1 genes and the down-regulated expression of lipogenic gene SREBP. The combination of MSCs and PIO also potentiated the decrease of abnormal myocardial pathological lesions in diabetic rats. Similarly, the inhibitory effects of MSCs on diabetic cardiac fibrosis and on the up regulations of TGF-β, collagen I and III gene expressions were partial but additive when combined with PIO. Therefore, combined therapy with PIO and BMCs transplantation could further potentiate the protective benefit of MSCs against diabetes and cardiac damage compared to MSCs monotherapy.

Kaempferol attenuates hyperglycemia-induced cardiac injuries by inhibiting inflammatory responses and oxidative stress

PURPOSE

Suppression of inflammation and oxidative stress is an attractive strategy to against diabetic cardiomyopathy (DCM). Kaempferol (KPF) exerts both anti-inflammatory and antioxidant pharmacological properties. However, little is known about the effect of KPF on protecting myocardial injury in diabetes. The present study aimed to investigate the effect of KPF on DCM and underlying mechanism.

METHODS

Anti-inflammation and anti-oxidative stress activities of KPF were evaluated in H9c2 cells or primary cardiomyocytes by real-time quantitate PCR, immunoblotting, immunofluorescence, ELISA, and FACS. Streptozotocin (STZ)-induced type 1 diabetes mellitus mice were constructed. Corresponding to experiments in vitro, the therapeutic effect of KPF was also assessed using heart tissues from mice.

RESULTS

KPF significantly inhibited high glocose (HG) induced expression of inflammatory cytokines and generation of ROS, leading to reduced fibrotic responses and cell apoptosis in vitro. KPF mediated DCM protective effects through inhibiting nuclear factor-κB (NF-κB) nucleus translocation and activating nuclear factor-erythroid 2 p45-related factor-2 (Nrf-2). In STZ-induced type 1 diabetic mouse model, KPF prevented diabetes-induced cardiac fibrosis and apoptosis. These changes were also accompanied by reducing inflammation and oxidative stress in diabetic mice hearts.

CONCLUSION

KPF is a potential therapeutic agent for the treatment of DCM, mechanically linked to inhibition of NF-κB and Nrf-2 activation.

A novel damage mechanism: Contribution of the interaction between necroptosis and ROS to high glucose-induced injury and inflammation in H9c2 cardiac cells

Recently, a novel mechanism known as 'programmed necrosis' or necroptosis has been shown to be another important mechanism of cell death in the heart. In this study, we investigated the role of necroptosis in high glucose (HG)-induced injury and inflammation, as well as the underlying mechanisms. In particular, we focused on the interaction between necroptosis and reactive oxygen species (ROS) in H9c2 cardiac cells. Our results demonstrated that the exposure of H9c2 cardiac cells to 35 mM glucose (HG) markedly enhanced the expression level of receptor-interacting protein 3 (RIP3), a kinase which promotes necroptosis. Importantly, co-treatment of the cells with 100 µM necrostatin-1 (a specific inhibitor of necroptosis) and HG for 24 h attenuated not only the increased expression level of RIP3, but also the HG-induced injury and inflammation, as evidenced by an increase in cell viability, a decrease in ROS generation, the attenuation of the dissipation of mitochondrial membrane potential and a decrese in the secretion levels of inflammatory cytokines, i.e., interleukin (IL)-1β and tumor necrosis factor (TNF)-α. Furthermore, treatment of the cells with 1 mM N-acetyl‑L‑cysteine (a scavenger of ROS) for 60 min prior to exposure to HG significantly reduced the HG-induced increase in the RIP3 expression level, as well as the injury and inflammatory response described above. Taken together, the findings of this study clearly demonstrate a novel damage mechanism involving the positive interaction between necroptosis and ROS attributing to HG-induced injury and inflammation in H9c2 cardiac cells.

miR-200c serves an important role in H5V endothelial cells in high glucose by targeting Notch1

Diabetic vasculopathy is the leading cause of impairment and death in diabetic patients, a variety of factors are involved in its underlying pathological process, however, endothelial cell (EC) dysfunction serves a significant role in the process. MicroRNAs (miRNAs) have emerged as potential therapeutic candidates, due to their ability to regulate multiple targets involved in ECs. The aim of the present study was to investigate the role of miR‑200c in regulating ECs in high glucose condition. To investigate the role of miR‑200c in regulating hyperglycemia induced ECs by targeting Notch1, ECs H5V cells were cultured in high sugar conditions to initiate the inhibition of Notch1, the same cells in normal medium as the control. H5V cells were transfected with miR‑200c mimics, miR‑200c inhibitors or scrambled oligonucleotide controls, respectively. Notch1 and Hes1 mRNA and protein expression level were detected by reverse transcription‑quantitative polymerase chain reaction and western blot analysis. The present study reported that miR‑200c was highly expressed by high glucose stimulation in H5V cells, however Notch1 was inhi-bited by high glucose, and it was also depressed by miR‑200c in high glucose conditions. Notch1 was identified as the target gene of miR‑200c, luciferase reporter assays confirmed the biochemical relationship for miR‑200c decreasing Notch1. The current findings revealed that miR‑200c may inhibit Notch1 expression in high glucose conditions, which suggested that miR‑200c mediating Notch1/Hes1 may involve in the process of vascular damage caused by hyperglycemia.

Effects of resveratrol on diabetes-induced vascular tissue damage and inflammation in male rats

Objective:

The present study aims to investigate the short-term effects of resveratrol on histopathological characteristics and inflammatory cytokines of the heart and thoracic aorta tissues in animal models of streptozotocin (STZ)-induced diabetes.

Methods:

Male Wistar rats were randomly divided into four groups; (1) control/vehicle, (2) control/20 mg/kg resveratrol, (3) diabetic/vehicle, (4) diabetic/20 mg/kg resveratrol. Heart and thoracic aorta were examined histopathologically and the levels of interleukin (IL)-1β, IL-18 and tissue necrosis factor (TNF)-α were analyzed by ELISA. Malondialdehyde (MDA) contents were determined with HPLC.

Results:

Diabetes group had significantly higher vascular MDA content (p<0.05) as compared with the control and resveratrol treated groups. Resveratrol significantly reduced vascular MDA level in diabetic animals (p<0.05). Significant elevation in IL-1β and TNF-α contents in thoracic aorta and IL-18 contents in cardiac and arterial tissues with diabetes were almost normalized with resveratrol treatment. Additionally, diabetic animals demonstrated significant endothelial damage, irregularities in smooth muscle fibers and degeneration of elastic fibers in thoracic aortas together with significant irregularities and hypertrophy in cardiac muscle fibers. Resveratrol significantly improved most of these histopathological alterations.

Conclusion:

Four-week-long intraperitoneal administration of resveratrol may restore the diabetes related inflammation and oxidative stress within the cardiovascular system.

[Irbesartan ameliorates cardiac inflammation in type 2 diabetic db/db mice]

OBJECTIVE

To investigate the protective effects of irbesartan against cardiac inflammation associated with diabetes and obesity in the db/db mouse model of type 2 diabetes and explore the underlying mechanisms.

METHODS

Twenty- four 10-week-old diabetic db/db mice were equally randomized into irbesartan treatment (50 mg/kg per day) group and model group, using 12 nondiabetic littermates (db/+) as the controls, The mice were treated with irbesartan or saline vehicle for 16 consecutive weeks, after which the heart pathology was observed and the heart weight, body weight, and serum levels of fasting blood glucose (FBG), total cholesterol(TC), and triglycerides(TG) were measured. The expression of nuclear factor-kappaB (NF-κB) p65 in the myocardium was assessed with immunohistochemistry, the protein levels of P-IκBα ,IκBα and β-actin were analyzed with Western blotting, and the pro-inflammatory cytokines IL-6 and TNF-α mRNA were detected using quantitative real-time PCR (qPCR).

RESULTS

Compared with db/+ mice, the saline-treated db/db mice developed obesity, hyperglycemia and hyperlipidemia (P<0.01). Histopathological examination of the heart tissue revealed inflammatory cell infiltration, increased myocardial interstitium and disorders of myocardial fiber arrangement. The diabetic mice showed increased P-IαBα and decreased IκBα protein levels, enhanced activity and expression of NF-κB in the hearts, and increased mRNA expression of IL-6 and TNF-α in the myocardium. These abnormalities were all associated with increased inflammatory response. Treatment with irbesartan improved the heart architecture and attenuated high glucose-induced inflammation in the diabetic mice.

CONCLUSION

Treatment with irbesartan attenuates cardiac inflammation in type 2 diabetic db/db mice, and this effect was probably associated with the suppression of cardiac angiotensin II and NF-κB signaling pathway.