Rapamycin Alleviates 2,4,6-Trinitrobenzene Sulfonic Acid-Induced Colitis through Autophagy Induction and NF-κB Pathway Inhibition in Mice.

Background: Recent genetic studies indicated that variants of autophagy genes were associated with the predisposition of Crohn's disease (CD). The autophagy deficiency may affect the innate and adaptive immunity, which is related to persistent and excessive inflammation of the bowel. However, it remains unclear how autophagy modulates the expression of immune response regulator NF-κB and proinflammatory cytokine TNF-α in CD. Aim: We aimed to investigate the role of rapamycin on the expression of NF-κB p65 and TNF-α in 2, 4, 6-trinitrobenzene sulfonic acid (TNBS)-induced mouse colitis and lipopolysaccharide (LPS)-induced HT-29 cells. Methods: TNBS-induced colitis mice were treated with saline or rapamycin, and the disease activity index (DAI) and histological scores of colonic mucosa were evaluated. The expressions of p65, ATG16L1 and LC3 were detected by western blot and immunohistochemistry staining. The monodansylcadaverine (MDC) staining and transmission electron microscopy were developed to study the autophagy in LPS-induced HT-29 cells. Expression of TNF-α from colon tissue and HT-29 cells were detected by ELISA. The expressions of p65, ATG16L1 and LC3 in active CD patients were also investigated. Results: Significantly more autophagosomes were observed in rapamycin-treated cells than in controls. Rapamycin remarkably upregulated the expression of ATG16L1 and LC3II, inhibited p65 nucleus translocation and secretion of TNF-α both in vivo and in vitro. The expression of both ATG16L1 and LC3II increased in mild to moderate CD specimens, while no significant difference was noted between severe CD and normal controls. The expression of p65 increased notably in severe CD compared to those in mild to moderate patients. Conclusions: In LPS-treated HT-29 cells and TNBS-induced colitis, p65 is overexpressed, which results in exaggerated secretion of TNF-α and induce or worsen the inflammation in the bowel. Rapamycin protects against colitis through induction of autophagy, thus inhibiting the activation of NF-κB pathway and secretion of TNF-α.

A comparative study on roles of natural killer T cells in two diet-induced non-alcoholic steatohepatitis-related fibrosis in mice.

BACKGROUND: Immune responses are important in the progression of non-alcoholic fatty liver disease (NAFLD). Natural killer T (NKT) cells are main components of the innate immune system that modulate immunity. However, the role of NKT cells in NAFLD remains controversial. OBJECTIVE: We aimed to investigate the role of NKT cells in non-alcoholic steatohepatitis (NASH)-related fibrosis in fast food diet (FFD)- and methionine choline-deficient (MCD) diet-induced mouse models. METHODS: Hepatic NKT cells were analysed in wild-type (WT) and CD1d-/- mice fed FFD or MCD diets. Hepatic pathology, cytokine profiles and liver fibrosis were evaluated. Furthermore, the effect of chronic administration of α-galactosylceramide (α-GalCer) on liver fibrosis was investigated in both FFD- and MCD-treated mice. RESULTS: FFD induced a significant depletion of hepatic NKT cells, thus leading to mild to moderate NASH and early-stage fibrosis, while mice fed MCD diets developed severe liver inflammation and progressive fibrosis without a significant change in hepatic NKT cell abundance. FFD induced a similar liver fibrogenic response in CD1d-/- and WT mice, while MCD induced a higher hepatic mRNA expression of Col1α1 and TIMP1 as well as relative fibrosis density in CD1d-/- mice than WT mice (31.8 vs. 16.3, p = .039; 40.0 vs. 22.6, p = .019; 2.24 vs. 1.59, p = .036). Chronic administration of α-GalCer induced a higher hepatic mRNA expression of TIMP1 in MCD-treated mice than controls (36.7 vs. 14.9, p = .005). CONCLUSION: NKT cells have protective roles in NAFLD as the disease progresses. During diet-induced steatosis, mild to moderate NASH and the early stage of fibrosis, hepatic NKT cells are relatively depleted, leading to a proinflammatory status. In severe NASH and the advanced stage of liver fibrosis, NKT cells play a role in inhibiting the NASH-related fibrogenic response. Chronic administration of α-GalCer induces NKT cell anergy and tolerance, which may play a role in promoting the liver fibrogenic response.

Positive regulation of endothelial Tom70 by metformin as a new mechanism against cardiac microvascular injury in diabetes.

Microvascular protection is the main mechanism of metformin against diabetic complications. Cardiac microvascular endothelial cells (CMECs) are the basic component of cardiac microvessels, and they suffer from oxidative stress and mitochondrial dysfunction under type 2 diabetes mellitus (T2DM). Translocase of the outer mitochondrial membrane 70 (Tom70) improves mitochondrial dysfunction, but its role in the hearts of T2DM patients remains unclear. The purpose of this study was to demonstrate the protective effect of metformin on diabetic cardiac microvascular injury and to identify the role of Tom70 in this effect. T2DM mice were established by multiple intraperitoneal injections of low-dose streptozotocin and 12-week high-fat feeding. CMECs were isolated and cultured with normal glucose (NG), high glucose (HG), and HG plus high fat (HG-HF) media. The results indicated that long-term metformin treatment partly reversed cardiovascular complication and mitigated cardiac microvascular injury in T2DM. In addition, exposure to HG-HF led to CMEC damage, aggravated oxidative stress, aggravated mitochondrial dysfunction, and reduced mitochondrial Tom70 expression, whereas upregulation of Tom70 significantly ameliorated these injuries. Furthermore, metformin treatment promoted Tom70 expression and effectively reversed CMEC injury induced by HG-HF. However, all of these effects were interrupted after Tom70 was knocked down. In conclusion, T2DM damages microvascular integrity by activating a cycle of decreased Tom70 expression, mitochondrial dysfunction, and reactive oxygen species (ROS) overload in CMECs. However, metformin suppresses oxidative stress, relieves mitochondrial dysfunction, and promotes the expression of Tom70, ultimately ameliorating diabetic microvascular injury and heart complications.

[Study of the Role and Mechanism of Asprosin/Spartin Pathway in Cardiac Microvascular Endothelial Injury Induced by Diabete Mellitus].

OBJECTIVE: To detect the effects and mechanism of asprosin (Asp) and spartin on the injury of mice cardiac microvascular endothelial cells (CMECs) induced by high glucose. METHODS: The cultured CMECs were divided into 2 groups, one group is normal group (5.5 mmol/L glucose in the medium) and another is HG group (30 mmol/L glucose in the medium). Real-time PCR (qRT-PCR) and Western blot were respectively used to detect the mRNA level of spastic paraplegia 20 (SPG20) and protein expression of spartin in CMECs. Upregulation or downregulation of the expression of spartin was achieved via transfection with adenovirus (Ad) or small interfering RNA (siRNA) respectively. CMECs with downregulation of spartin expression were firstly treated with anti-oxidant N-acetylcysteine (NAC) or Asp respectively for 48 h, and then were interfered with 30 mmol/L glucose for 24 h afterward. The apoptosis of cell was detected by flow cytometry. Nitric oxide (NO) production was detected by NO probe and ELISA kit. The intracellular reactive oxygen species (ROS) levels were tested by DHE staining and ELISA kit. Type 2 diabetic model mice were established and then divided into T2DM group and T2DM+Asp group. After the model mice were established successfully (random blood glucose was more than 16.7 mmol/L), Asp (1 µg/g) was intraperitoneally injected once a day. After 2 weeks, mice echocardiography was performed to test cardiac diastolic function. The integrity of the microvascular endothelium was observed by scanning electron microscopy. RESULTS: Compared with the normal group, the mRNA level of SPG20 and protein expression of spartin in mice CMECs of HG group were significantly reduced (P < 0.05). Under the condition of high glucose, Ad transfection induced significant decrease of the intracellular ROS level and the apoptosis level of the CMECs (P < 0.05), while NO increased after Ad transfection. In contrast, siRNA intervention resulted in opposite effect. In addition, the antioxidant NAC partly reversed the above changes caused by downregulating spartin. Asp upregulated the level of SPG20 mRNA and spartin protein expression in CMECs, reduced ROS production, reduced apoptosis and increased NO production. However, intervention effects of Asp, such as decreasing of ROS production, inhibiting apoptosis of CMECs and increasing of NO production, were partly reversed in spartin downregulated cells. In vivo, we found that Asp can improve cardiac function and increase the integrity and smoothness of cardiac microvascular endothelium in type 2 diabetic mice. CONCLUSION: Asp can inhibit oxidative stress in mice CMECs through upregulating spartin signaling pathway, thereby alleviating the damage of microvascular endothelium in diabetic heart.

Plin5/p-Plin5 Guards Diabetic CMECs by Regulating FFAs Metabolism Bidirectionally.

BACKGROUND: Hyper-free fatty acidemia (HFFA) impairs cardiac capillaries, as well as type 2 diabetes mellitus (T2DM). Perilipin 5 (Plin5) maintains metabolic balance of free fatty acids (FFAs) in high oxidative tissues via the states of nonphosphorylation and phosphorylation. However, when facing to T2DM-HFFA, Plin5's role in cardiac microvascular endothelial cells (CMECs) is not defined. METHODS: In mice of WT or Plin5-/-, T2DM models were rendered by high-fat diet combined with intraperitoneal injection of streptozocin. CMECs isolated from left ventricles were incubated with high glucose (HG) and high FFAs (HFFAs). Plin5 phosphorylation was stimulated by isoproterenol. Plin5 expression was knocked down by small interfering RNA (siRNA). We determined cardiac function by small animal ultrasound, apoptotic rate by flow cytometry, microvessel quantity by immunohistochemistry, microvascular integrity by scanning electron microscopy, intracellular FFAs by spectrophotometry, lipid droplets (LDs) by Nile red staining, mRNAs by quantitative real-time polymerase chain reaction, proteins by western blots, nitric oxide (NO) and reactive oxygen species (ROS) by fluorescent dye staining and enzyme-linked immunosorbent assay kits. RESULTS: In CMECs, HFFAs aggravated cell injury induced by HG and activated Plin5 expression. In mice with T2DM-HFFA, Plin5 deficiency reduced number of cardiac capillaries, worsened structural incompleteness, and enhanced diastolic dysfunction. Moreover, in CMECs treated with HG-HFFAs, both ablation and phosphorylation of Plin5 reduced LDs content, increased intracellular FFAs, stimulated mitochondrial ß-oxidation, added ROS generation, and reduced the expression and activity of endothelial nitric oxide synthase (eNOS), eventually leading to increased apoptotic rate and decreased NO content, all of which were reversed by N-acetyl-L-cysteine. CONCLUSION: Plin5 preserves lipid balance and cell survival in diabetic CMECs by regulating FFAs metabolism bidirectionally via the states of nonphosphorylation and phosphorylation.

Potential Protective Mechanism in the Cardiac Microvascular Injury.

Cardiac microvascular injury often occurs in patients with type 2 diabetes mellitus (T2DM) who develop hyperglycemia and hyperlipidemia. However, besides reported contradictory roles in cardiac diseases, the function of TRPV1 (transient receptor potential vanilloid 1) in cardiac microvessels is not well defined. This study was performed to determine the detailed role of TRPV1 in cardiac microvascular endothelial cells (CMECs) in T2DM. T2DM mice were established by multiple injections of low-dose streptozotocin and high-fat feeding. CMECs were cultured separately in mediums of normal glucose, high glucose (HG), high fatty acid (HF), and HG plus HF (HG-HF). HG-HF inhibited TRPV1 expression in CMECs, reducing cellular Ca2+ content ([Ca2+]i). T2DM impaired cardiac function, disturbed glucose uptake, and damaged microvascular barrier, which were further aggravated by TRPV1-/- Exposure to HG-HF, particularly in TRPV1-/- CMECs, led to a higher level of apoptosis and a lower level of nitric oxide production in viable CMECs. HG-HF markedly enhanced generation of reactive oxygen species and nitrotyrosine, especially in the absence of TRPV1. H2O2 administration reduced TRPV1 expression in CMECs. HG-HF significantly depressed expression of PGC-1α (peroxisome proliferator-activated receptor-γ coactivator-1α) and OPA1 (optic atrophy 1) by reducing [Ca2+]i, whereas OPA1 supplementation partly reversed those detrimental effects induced by TRPV1-/- Furthermore, capsaicin treatment not only attenuated CMECs injury induced by HG-HF but also mitigated cardiac microvascular injury induced by T2DM. Collectively, T2DM leads to cardiac microvascular injury by exacerbating the vicious circle of TRPV1 blockage and reactive oxygen species overload. Long-term capsaicin can protect cardiac microvessels against T2DM via suppressing oxidative/nitrative stress mediated by TRPV1/Ca2+/PGC-1α/OPA1 pathway in CMECs.

Melatonin attenuates postmyocardial infarction injury via increasing Tom70 expression.

Mitochondrial dysfunction leads to reactive oxygen species (ROS) overload, exacerbating injury in myocardial infarction (MI). As a receptor for translocases in the outer mitochondrial membrane (Tom) complex, Tom70 has an unknown function in MI, including melatonin-induced protection against MI injury. We delivered specific small interfering RNAs against Tom70 or lentivirus vectors carrying Tom70a sequences into the left ventricles of mice or to cultured neonatal murine ventricular myocytes (NMVMs). At 48 h post-transfection, the left anterior descending coronary arteries of mice were permanently ligated, while the NMVMs underwent continuous hypoxia. At 24 h after ischemia/hypoxia, oxidative stress was assessed by dihydroethidium and lucigenin-enhanced luminescence, mitochondrial damage by transmission electron microscopy and ATP content, and cell apoptosis by terminal deoxynucleotidyl transferase dUTP nick-end labeling and caspase-3 assay. At 4 weeks after ischemia, cardiac function and fibrosis were evaluated in mice by echocardiography and Masson's trichrome staining, respectively. Ischemic/hypoxic insult reduced Tom70 expression in cardiomyocytes. Tom70 downregulation aggravated post-MI injury, with increased mitochondrial fragmentation and ROS overload. In contrast, Tom70 upregulation alleviated post-MI injury, with improved mitochondrial integrity and decreased ROS production. PGC-1α/Tom70 expression in ischemic myocardium was increased with melatonin alone, but not when combined with luzindole. Melatonin attenuated post-MI injury in control but not in Tom70-deficient mice. N-acetylcysteine (NAC) reversed the adverse effects of Tom70 deficiency in mitochondria and cardiomyocytes, but at a much higher concentration than melatonin. Our findings showed that Tom70 is essential for melatonin-induced protection against post-MI injury, by breaking the cycle of mitochondrial impairment and ROS generation.

Does growth differentiation factor 11 protect against myocardial ischaemia/reperfusion injury? A hypothesis.

The pathogenesis of myocardial ischaemia/reperfusion injury is multifactorial. Understanding the mechanisms of myocardial ischaemia/reperfusion will benefit patients with ischaemic heart disease. Growth differentiation factor 11 (GDF11), a member of the secreted transforming growth factor-ß superfamily, has been found to reverse age-related hypertrophy, revealing the important role of GDF11 in cardiovascular disease. However, the functions of GDF11 in myocardial ischaemia/reperfusion have not been elucidated yet. A number of signalling molecules are known to occur downstream of GDF11, including mothers against decapentaplegic homolog 3 (SMAD3) and forkhead box O3a (FOXO3a). A hypothesis is presented that GDF11 has protective effects in acute myocardial ischaemia/reperfusion injury through suppression of oxidative stress, prevention of calcium ion overload and promotion of the elimination of abnormal mitochondria via both canonical (SMAD3) and non-canonical (FOXO3a) pathways. Since circulating GDF11 may mainly derive from the spleen, the lack of a spleen may make the myocardium susceptible to damaging insults. Administration of GDF11 may be an efficacious therapy to protect against cardiovascular diseases in splenectomized patients.

Melatonin prevents adverse myocardial infarction remodeling via Notch1/Mfn2 pathway.

Mitochondrial dysfunction is linked with myocardial infarction (MI), a disorder in which Notch1 has attracted increasing attention. However, the involvement of Notch1 in mitochondrial impairment after an MI is poorly understood, as is the role of mitochondrial fusion-associated protein 2 (Mfn2). Moreover, whether melatonin potentiates the Notch1/Mfn2 pathway in post-MI cardiac damage remains unclear. In our study, small interfering RNAs against Notch1 or Mfn2 and Jagged1 peptide were delivered via intramyocardial injection. At 3 days after these treatments, MI was induced by ligation of the anterior descending branch. We found that this ablation of Notch1 or Mfn2 aggravated post-MI injury, including worsened mitochondrial damage and increased generation of reactive oxygen species (ROS). In contrast, Jagged1 improved mitochondrial structure and function, decreased ROS production and attenuated post-MI injury. Interestingly, though Mfn2 expression was mildly regulated by Notch1 signaling in myocardium, Mfn2 deficiency nearly eliminated the cardioprotection by Jagged1, as evidenced by suppressed cardiac function, aggravated myocardial fibrosis, increased cell apoptosis, worsened mitochondrial impairment and enhanced oxidative stress. These observations revealed that Mfn2 plays an indispensable role in protection against MI-induced injury by Notch1. The mechanism might involve disrupting a damaging cycle of mitochondrial damage and ROS generation. Furthermore, melatonin activated Notch1 signaling and increased Mfn2 expression were reversed by luzindole, a nonselective antagonist of the melatonin receptor. Notably, melatonin attenuated post-MI injury in normal mice, but not in mice deficient in Notch1 or Mfn2. These results demonstrate that melatonin attenuates post-MI injury via the Notch1/Mfn2 pathway in a receptor-dependent manner.

Meta-analysis of the efficacy of sorafenib for hepatocellular carcinoma.

PURPOSE: By carrying out a meta-analysis of randomized controlled trials that compared sorafenib or combined chemotherapy with placebo or combined chemotherapy, the effectiveness of sorafenib in hepatocellular carcinoma was evaluated in the present study, which also provided clinical practice guidelines of evidence-based-medicine. METHODS: We reviewed PubMed citations concerning sorafenib treating hepatocellular carcinoma in randomized controlled trials from Jan 2000 to July 2012. All the literature was extracted by Cochrane systematic reviews and underwent meta-analysis with RewMan 5.0 software. RESULTS: Finally, four papers documenting randomized controlled studies were included. Compared with controls, sorafenib was shown to significantly increase overall survival (OS), time to progression (TTP), and disease control rates (DCR), but not the time to symptom progression (TTSP) in hepatocellular carcinoma patients. The incidence of grade-III/IV adverse reactions, including hand- foot-skin reactions, diarrhea, hypertension and skin rash or desquamation, in sorafenib treatment group was higher than that in controls. However, there was no significant difference in the incidence of hypodynamia between the two groups. CONCLUSIONS: Sorafenib exerts significant curative effects in hepatocellular carcinoma.