Cystathionine γ-lyase S-sulfhydrates SIRT1 to attenuate myocardial death in isoprenaline-induced heart failure.

OBJECTIVE: Hydrogen sulfide (H2S), the third gasotransmitter, plays a critical role in protecting against heart failure. Sirtuin-1 (SIRT1) is a highly conserved histone deacetylase that has a protective role in the treatment of heart failure by regulating the deacetylation of some functional proteins. This study investigates the interaction between SIRT1 and H2S in heart failure and the underlying mechanisms. METHODS AND RESULTS: Using endogenous H2S-generating enzyme cystathionine γ-lyase (CSE) knockout mice, we found that CSE deficiency aggravated isoprenaline-induced cardiac injury. Treatment with H2S attenuated atrial natriuretic peptide level, brain natriuretic peptide level, improved cardiac function. Moreover, H2S treatment potentiated myocardial SIRT1 expression. Silencing CSE abolished intracellular SIRT1 expression. Furthermore, CSE/ H2S S-sulfhydrated SIRT1 at its zinc finger domains and augmented its zinc ion binding activity to stabilize the alpha-helix structure. DISCUSSION: In conclusion, these results uncover that a novel mechanism that CSE/H2S S-sulfhydrated SIRT1 to prevent heart dysfunction through modulating its activity.

Paris saponin VII extracted from Trillium tschonoskii induces autophagy and apoptosis in NSCLC cells.

ETHNOPHARMACOLOGICAL RELEVANCE: Trillium tschonoskii Maxim, a perennial herb of the Trilliaceae, has been widely used to treat inflammation, hypertension and cancer. We investigated Paris saponin VII's (PS VII), isolated from Trillium tschonoskii Maxim, function in mediating autophagy and apoptosis in NSCLC cells. MATERIALS AND METHODS: We treated various NSCLC cells with different concentrations of PS Ⅶ and then measure the cell apoptosis by using flow cytometry assays and western blot. Autophagy were investigated by using western blot, transmission electron microscopy and immunofluorescence analysis. We also use a xenograft model of nude mice to measure the effect of PS Ⅶ in vivo. RESULTS: Treatment with PS Ⅶ significantly inhibit NSCLC cell growth, especially for A549 (IC50 = 1.53 µM). Moreover, PS VII induces caspase-dependent apoptosis and autophagy through AMPK-ULK1 pathway. After blocking autophagy by 3-methyladenine (3-MA), PS VII induced cell death was significantly increased. In vivo, the co-treatment with PS VII and 3-MA dramatically inhibited A549 tumor growth in immune deficient mice and has similar inhibition rates as cisplatin group. CONCLUSION: Our results suggest that a combination of PS VII and autophagy inhibitor may be a potential anticancer strategy in the NSCLC therapy.

Amelioration of mitochondrial dysfunction in heart failure through S-sulfhydration of Ca2+/calmodulin-dependent protein kinase II.

AIMS: Ca2+/calmodulin-dependent protein kinase II (CaMKII) plays a critical role in the development of heart failure and in the induction of myocardial mitochondrial injury. Recent evidence has shown that hydrogen sulfide (H2S), produced by the enzyme cystathionine γ-lyase (CSE), improves the cardiac function in heart failure. However, the cellular mechanisms for this remain largely unknown. The present study was conducted to determine the functional role of H2S in protecting against mitochondrial dysfunction in heart failure through the inhibition of CaMKII using wild type and CSE knockout mouse models. RESULTS: Treatment with S-propyl-L-cysteine (SPRC) or sodium hydrosulfide (NaHS), modulators of blood H2S levels, attenuated the development of heart failure in animals, reduced lipid peroxidation, and preserved mitochondrial function. The inhibition CaMKII phosphorylation by SPRC and NaHS as demonstrated using both in vivo and in vitro models corresponded with the cardioprotective effects of these compounds. Interestingly, CaMKII activity was found to be elevated in CSE knockout (CSE-/-) mice as compared to wild type animals and the phosphorylation status of CaMKII appeared to relate to the severity of heart failure. Importantly, in wild type mice SPRC was found to promote S-sulfhydration of CaMKII leading to reduced activity of this protein, however, in CSE-/- mice S-sulfhydration was abolished following SPRC treatment. INNOVATION AND CONCLUSIONS: A novel mechanism depicting a role of S-sulfhydration in the regulation of CaMKII is presented. SPRC mediated S-sulfhydration of CaMKII was found to inhibit CAMKII activity and to preserve cardiovascular homeostasis.

Novel H2S-NO hybrid molecule (ZYZ-803) promoted synergistic effects against heart failure.

Therapeutic strategies that increase hydrogen sulfide (H2S) or nitric oxide (NO) are cytoprotective in various models of cardiovascular injury. However, the nature of interaction between H2S and NO in heart failure and the underlying mechanisms for the protective effects remain undefined. The present study tested the cardioprotective effect of ZYZ-803, a novel synthetic H2S-NO hybrid molecule that decomposed to release H2S and NO. ZYZ-803 dose dependently improved left ventricular remodeling and preserved left ventricular function in the setting of isoprenaline-induced heart failure. The cardioprotective effect of ZYZ-803 is significantly more potent than that of H2S and/or NO donor alone. ZYZ-803 stimulated the expression of cystathionine γ-lyase (CSE) for H2S generation and the activity of endothelial NO synthase (eNOS) for NO production. Blocking CSE and/or eNOS suppressed ZYZ-803-induced H2S and NO production and cardioprotection. ZYZ-803 increased vascular endothelial growth factor (VEGF) concentration and cyclic guanosine 5'-monophosphate (cGMP) level. Moreover, ZYZ-803 upregulated the endogenous antioxidants, glutathione peroxidase (GPx) and heme oxygenase 1 (HO-1). These findings indicate that H2S and NO cooperatively attenuates left ventricular remodeling and dysfunction during the development of heart failure through VEGF/cGMP pathway and ZYZ-803 provide expanding insight into strategies for treatment of heart failure.

Nucleotidyl transferase TUT1 inhibits lipogenesis in osteosarcoma cells through regulation of microRNA-24 and microRNA-29a.

Osteosarcoma is the most common type of bone cancer. In the present study, by way of PCR-based microarrays, we found that TUT1, a nucleotidyl transferase, was significantly downregulated in osteosarcoma, compared with adjacent normal tissues. In the current study, we performed PCR-based microarrays using the cDNA prepared from osteosarcoma and adjacent normal tissues. The enforced expression of TUT1 was able to inhibit cell proliferation in U2OS and MG63 cells, while its knockdown using small interfering RNA (siRNA) oligos promoted cell proliferation. At the molecular level, we found that TUT1 could inhibit the expression levels of PPARgamma and SREBP-1c, two key regulators in lipogenesis, through upregulation of microRNA-24 and microRNA-29a. Therefore, our results suggest that TUT1 may act as a tumor suppressor for osteosarcoma, which might provide a novel mechanism for the tumor development.

Sequential arabinosylcytosin with or without fludarabine in paracmastic patients with acute myeloid leukemia.

The purpose of this study is to assess how fludarabine (Fa) influences arabinosylcytosin's (Ara-C) mode of action. Plasma, cerebrospinal and urine samples were withdrawn from two study groups at specific time points and analyzed by HPLC. Group A was treated with Ara-C only whereas Group B was treated with Fa+Ara-C. The two study groups are all undergoing complete remission (CR). The Ara-C dose for Group A was 3g/m2 x 2, and the AUC(0-4) was 5.131 +/- 0.936. The Ara-C dose for Group B was 2g/m2 x 2, and the AUC(0-4) was 12.245 +/- 3.863. The AUC(0-4) for Group B is more than twice the AUC(0-4) for Group A, and these results indicate that Fa conduces a synergistic increase in the concentration and AUC of Ara-C in plasma and in cerebrospinal fluid. The pharmacokinetics between the different dose treatments was statistically different (P = 0.016). The differences in the ratios of C(Ara-u) to C(Ara-C), and in the Tmax between Groups A and B could indicate whether or not Ara-C combined with Fa. Although Group B demonstrates a higher AUC(0-4) with lower doses of Ara-C (2 g/m2 x 2), the adverse drug reaction (ADR) and bone inhibition were not more pronounced in Group B compared to Group A. These results are based on a limited number of case studies, hence, additional studies are necessary to support and prove this hypothesis.

Luteolin inhibits lysophosphatidylcholine-induced apoptosis in endothelial cells by a calcium/mitocondrion/caspases-dependent pathway.

Luteolin, a naturally occurring polyphenol flavonoid, has demonstrated some beneficial modulation toward the endothelium. This study aims to investigate the effects of luteolin on lysophosphatidylcholine (LPC)-induced apoptosis, a key event in the pathogenesis of atherosclerosis, in endothelial cells. Luteolin reduced not only LPC-induced cell death but also lactate dehydrogenase (LDH) leakage. Luteolin inhibition of LPC-induced apoptosis in endothelial cells demonstrated its protection against the cytotoxicity of LPC. LPC-induced apoptosis is characterized by a calcium-dependent mitochondrial pathway, involving calcium influx, activation of calpains, cytochrome C release and caspases activation. Luteolin reduced calcium influx. It also inhibited calpains activation and prevented the release of cytochrome C from mitochondrion. The inhibition of cytochrome C release by luteolin blocked the activation of caspase-3 and thus prevented subsequent endothelial cell apoptosis. These results suggested that luteolin inhibits LPC-induced apoptosis in endothelial cells through the blockage of the calcium-dependent mitochondrial pathway.