Hydrogen sulfide functions as a micro-modulator bound at the copper active site of Cu/Zn-SOD to regulate the catalytic activity of the enzyme.

The present study examines whether there is a mechanism beyond the current concept of post-translational modifications to regulate the function of a protein. A small gas molecule, hydrogen sulfide (H2S), was found to bind at active-site copper of Cu/Zn-SOD using a series of methods including radiolabeled binding assay, X-ray absorption near-edge structure (XANES), and crystallography. Such an H2S binding enhanced the electrostatic forces to guide the negatively charged substrate superoxide radicals to the catalytic copper ion, changed the geometry and energy of the frontier molecular orbitals of the active site, and subsequently facilitated the transfer of an electron from the superoxide radical to the catalytic copper ion and the breakage of the copper-His61 bridge. The physiological relevance of such an H2S effect was also examined in both in vitro and in vivo models where the cardioprotective effects of H2S were dependent on Cu/Zn-SOD.

Pharmacological treatment of neuropsychiatric symptoms of dementia: a network meta-analysis.

BACKGROUND: Pharmacological treatments are very common to be used for alleviating neuropsychiatric symptoms (NPS) in dementia. However, decision on drug selection is still a matter of controversy. AIMS: To summarise the comparative efficacy and acceptability of currently available monotherapy drug regimens for reducing NPS in dementia. METHOD: We searched PubMed, MEDLINE, EMBASE and Cochrane Central Register of Controlled Trials between inception and 26 December 2022 without language restrictions; and reference lists scanned from selected studies and systematic reviews. Double-blind randomised controlled trials were identified from electronic databases for reporting NPS outcomes in people with dementia. Primary outcomes were efficacy and acceptability. Confidence in the evidence was assessed using Confidence in Network Meta-Analysis (CINeMA). RESULTS: We included 59 trials (15,781 participants; mean age, 76.6 years) and 15 different drugs in quantitative syntheses. Risperidone (standardised mean difference [SMD] -0.20, 95% credible interval [CrI] -0.40 to -0.10) and galantamine (-0.20, -0.39 to -0.02) were more effective than placebo in short-term treatment (median duration: 12 weeks). Galantamine (odds ratio [OR] 1.95, 95% CrI 1.38-2.94) and rivastigmine (1.87, 1.24-2.99) were associated with more dropouts than placebo, and some active drugs. Most of the results were rated as low or very low according to CINeMA. CONCLUSIONS: Despite the scarcity of high-quality evidence, risperidone is probably the best pharmacological option to consider for alleviating NPS in people with dementia in short-term treatment when considering the risk-benefit profile of drugs.

Study on the medication rule of traditional Chinese medicine in the treatment of acute pancreatitis based on machine learning technology.

BACKGROUND: To analyze the rule of traditional Chinese medicine in the treatment of acute pancreatitis (AP). METHODS: Using machine learning technology and artificial intelligence, we collected 516 traditional Chinese medicine compounds for treating AP in the recent past 20 years, and analyzed the application of Chinese medicine in the field of AP. The data set was established by the ingredients of each prescription and its corresponding effectiveness. 90% of the data was divided into the training set, and the remaining 10% of the data was used as the test set. We employed random forest method to build a model to predict the efficacy of the prescriptions in the treatment of AP. The R-squared score and mean absolute error was used to evaluate the model's performance. RESULTS: The most frequently used drugs were rhubarb, Radix Bupleuri, Fructus Aurantii Immaturus, and Mirabilite. Rhubarb and Rhizoma Corydalis had the greatest curative effect. The random forest model that fit all data showed that its R-squared score reached 0.8021. And the results predicted on the test set showed that the R-squared score reached 0.7318. CONCLUSIONS: Soothing the liver, promoting qi, clearing heat, removing obstructions of organs, activating blood, and resolving stagnation are the treatment methods for AP.

Associations of Anxiety with Amyloid, Tau, and Neurodegeneration in Older Adults without Dementia: A Longitudinal Study.

BACKGROUND: The pathophysiological process of amyloid-ß, tau deposition, and neurodegeneration of Alzheimer's disease (AD) begin in a preclinical phase, while anxiety is associated with an increased risk of AD in preclinical phase. OBJECTIVE: To examine the relationships between anxiety and amyloid-ß, tau deposition, and neurodegeneration. To test the hypothesis that anxiety could predict clinical progression in the elderly without dementia. METHODS: 1,400 participants from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database were included in the study and were studied over a median period of 3 years. In multivariable models, the cross-sectional and longitudinal associations between anxiety and amyloid-ß PET, tau PET, and FDG PET SUVRs in participants without dementia were explored using Spearman rank correlation, logistic regression model, multiple linear regression model, Kaplan-Meier survival curves, and Cox proportional hazards model. The association between baseline anxiety and clinical progression was also explored. RESULTS: There was a positive correlation between anxiety and amyloid-ß deposition (r = 0.11, p = 0.0017) and a negative correlation between anxiety and neurodegeneration (r = -0.13, p = 0.00022). MCI participants with anxiety showed a faster clinical progression of dementia (HR = 1.56, p = 0.04). Non-anxious participants with more amyloid-ß deposition or more severe neurodegeneration displayed accelerated development into anxiety (HR = 2.352, p < 0.0001; HR = 2.254, p < 0.0001). CONCLUSION: Anxiety was associated with amyloid-ß deposition and neurodegeneration in non-dementia elderly. Anxiety in MCI predicted conversion to dementia. Anxiety may play a selective role and prediction of disease progression in the early phase of AD.

Genome-Wide Association Study of Cerebral Microbleeds on MRI.

Cerebral microbleeds are the presence of a group of pathological processes affecting the small arteries, arterioles, capillaries, and venules of the brain. Previous studies showed that cerebral microbleeds were associated with higher risk of dementia and stroke. We conducted a genome-wide association study of cerebral microbleeds to identify novel loci associated with the presence and progression of cerebral microbleeds. This study included 454 individuals composed by 176 subjects with cerebral microbleeds and 278 subjects without cerebral microbleeds in a non-Hispanic/Latino white population. Association of genetic variants with the presence and progression of cerebral microbleeds was assessed by logistic regression model. Potential genetic risk variants Apolipoprotein E (ApoE) polymorphisms were independently genotyped and checked the association with the presence and progression of cerebral microbleeds. No single-nucleotide polymorphisms (SNPs) associated with the presence or progression of cerebral microbleeds were identified at genome-wide significant level (P < 1 × 10-8). A total of 19 SNPs were associated with the presence of microbleeds at suggestive level (P < 1 × 10-5). One SNP was associated with lower progression risk for cerebral microbleeds with suggestive evidence (P < 1 × 10-5). ApoE ε4ε4 was independently associated with the presence and progression of cerebral microbleeds (odds ratio = 2.54, 95% confidence interval 1.08-6.00 and odds ratio = 5.1, 95% confidence interval 1.36-19.16). We highlighted 19 novel SNPs associated with the presence of cerebral microbleeds and one novel SNP associated with the progression of cerebral microbleeds for the first time. ApoE ε4ε4 was confirmed independently associated with the presence and progression of cerebral microbleeds.

Associations of White Matter Hyperintensities with Cognitive Decline: A Longitudinal Study.

White matter hyperintensities (WMHs), mainly caused by cerebrovascular injury, may lead to cognitive impairment. In order to identify whether the volume of WMHs is associated with cognitive decline over years, this longitudinal study involved 818 individuals from the ADNI-2 dataset from August 2010 to May 2017. Cross-sectional and longitudinal associations of WMHs with 8 cognitive domains were explored, using Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), Clinical Dementia Rating Sum of Boxes (CDRSB), Alzheimer Disease Assessment Scale-Cognitive (ADAS-Cog13), Rey Auditory Verbal Learning Test (RAVLT), Functional Assessment Questionnaire (FAQ), executive function (ADNI-EF), and memory function (ADNI-Mem). The association analyses were performed using multiple linear regression models, linear mixed models, Spearman rank correlation, and Kaplan-Meier survival curves. The volumes of WMHs were greater in patients with Alzheimer's disease (AD) dementia compared with controls (p < 0.001) and mild cognitive impairment (p = 0.006) patients at baseline. The bigger volumes of WMHs correlated with worse performances on ADAS-Cog13 and ADNI-EF (p = 0.029; p = 0.003) at baseline and MMSE, MoCA, CDRSB, ADAS-Cog13, FAQ, and ADNI-Mem (overall p < 0.05) longitudinally, after adjusting for age, sex, educational level, apolipoprotein E ɛ4 genotype, hypertension, hyperlipidemia, diabetes, smoking, infarction, and diagnosis. Additionally, the correlations between the change rate of WMHs and change rates of MMSE, MoCA, CDRSB, FAQ, ADNI-EF, and ADNI-Mem were statistically significant. Furthermore, patients with high WMH volumes showed an increased likelihood of dementia. The results of the study suggest that WMH volume is associated with cognitive decline, and it contributes to the conversion to AD.

[The Molecular Switches and Atomic Biological Mechanisms Underlying the Physiological and Pathophysio-logical Effects of Hydrogen Sulfide to Regulate Its "Receptors"].

Hydrogen sulfide (H2S)has emerged as pivotal signaling molecules since it is recognized as the third gasotransmitter together with nitric oxide and carbon monoxide. The development of detecting technologies contributed to the research in H2S biology.H2S plays significant roles in human body systems, such as the cardiovascular system, nervous system, respiratory system etc.. Alterations of H2S concentrations have been connected with many diseases. Hypertension, atherosclerosis, neurodegenerative disorder, asthma and many other diseases are found to be related with abnormal H2S metabolism. It has become a potential drug for therapeutic purposes. Understanding the mechanism of H2S biology, including a molecular switch contained in its "receptor", has deepened the research on how small molecules regulate big molecules, as well as providing new strategy for the therapeutic approaches for varies of diseases.

The mitochondrion interfering compound NPC-26 exerts potent anti-pancreatic cancer cell activity in vitro and in vivo.

The development of novel anti-pancreatic cancer agents is extremely important. Here, we investigated the anti-pancreatic cancer activity by NPC-26, a novel mitochondrion interfering compound. We showed that NPC-26 was anti-proliferative and cytotoxic to human pancreatic cancer cells, possibly via inducing caspase-9-dependent cell apoptosis. Pharmacological inhibition or shRNA-mediated silence of caspase-9 attenuated NPC-26-induced pancreatic cancer cell death and apoptosis. Further, NPC-26 treatment led to mitochondrial permeability transition pore (mPTP) opening in the cancer cells, which was evidenced by mitochondrial depolarization, ANT-1(adenine nucleotide translocator-1)-Cyp-D (cyclophilin-D) association and oxidative phosphorylation disturbance. mPTP blockers (cyclosporin and sanglifehrin A) or shRNA-mediated knockdown of key mPTP components (Cyp-D and ANT-1) dramatically attenuated NPC-26-induced pancreatic cancer cell apoptosis. Importantly, we showed that NPC-26, at a low concentration, potentiated gemcitabine-induced mPTP opening and subsequent pancreatic cancer cell apoptosis. In vivo, NPC-26 intraperitoneal injection significantly suppressed the growth of PANC-1 xenograft tumors in nude mice. Meanwhile, NPC-26 sensitized gemcitabine-mediated anti-pancreatic cancer activity in vivo. In summary, the results of this study suggest that NPC-26, alone or together with gemcitabine, potently inhibits pancreatic cancer cells possibly via disrupting mitochondrion.

Hydrogen sulphide in cardiovascular system: A cascade from interaction between sulphur atoms and signalling molecules.

As a gasotransmitter, hydrogen sulphide exerts its extensive physiological and pathophysiological effects in mammals. The interaction between sulphur atoms and signalling molecules forms a cascade that modulates cellular functions and homeostasis. In this review, we focus on the signalling mechanism underlying the effect of hydrogen sulphide in the cardiovascular system and metabolism as well as the biological relevance to human diseases.

H2S Is a Promoter of Angiogenesis: Identification of H2S "Receptors" and Its Molecular Switches in Vascular Endothelial Cells.

Angiogenesis is a physiological process in organ development and also a compensatory response in ischemia. When ischemia occurs, oxygen sensors in vascular endothelial cells sense the decrease in oxygen, thus activating downstream signaling pathways to promote the proliferation, migration, and tube formation of the endothelial cells. The new vasculatures are formed by sprouting from preexisting vessels, in order to maintain oxygen homeostasis in ischemic tissues (Folkman and Shing 1992). Collateral circulation is sometimes established under chronic ischemic conditions such as chronic myocardial ischemia (Banai et al. 1994). However, naturally occurring angiogenesis is usually not sufficient to compensate for ischemia in ischemic tissues. Proangiogenic drugs may be useful to promote angiogenesis in these diseases.

The directional response of chemotactic cells depends on a balance between cytoskeletal architecture and the external gradient.

Polarized migrating cells display signal transduction events, such as activation of phosphatidylinositol 3-kinase (PI3K) and Scar/Wave, and respond more readily to chemotactic stimuli at the leading edge. We sought to determine the basis of this polarized sensitivity. Inhibiting actin polymerization leads to uniform sensitivity. However, when human neutrophils were "stalled" by simultaneously blocking actin and myosin dynamics, they maintained the gradient of responsiveness to chemoattractant and also displayed noise-driven PIP3 flashes on the basal membrane, localized toward the front. Thus, polarized sensitivity does not require migration or cytoskeletal dynamics. The threshold for response is correlated with the static F-actin distribution, but not cell shape or volume changes, membrane fluidity, or the preexisting distribution of PI3K. The kinetics of responses to temporal and spatial stimuli were consistent with the local excitation global inhibition model, but the overall direction of the response was biased by the internal axis of polarity.

ERCC1 single nucleotide polymorphism C8092A, but not its expression is associated with survival of esophageal squamous cell carcinoma patients from Fujian province, China.

Esophageal carcinoma is one of the world's deadliest cancers. Esophageal squamous cell carcinoma (ESCC) is more frequent than adenocarcenoma (AC) in China. Platinum-based chemotherapy with surgical resection is a common treatment approach for ESCC; however, the treatment response is uncertain. Evidence suggests polymorphisms in genes encoding excision repair cross-complementing group 1 (ERCC1), a protein involved in nuclear excision repair (NER), may help predict response to cisplatin and other platinum-based chemotherapeutics. Multiple ERCC1 single nucleotide polymorphisms (SNPs) have been associated with platinum chemotherapy response. Two common SNPs occur at the C8092A and C118T loci. Our study aimed to determine if 1) an association exists between ERCC1 tumor expression and patient survival, 2) whether adjuvant therapy influence on survival is related to histological ERCC1 presence in tumor cell nuclei, and 3) whether other clinicopathological characteristics in a cohort of patients following surgery for various stages of ESCC are associated with tumor ERCC1 expression. One hundred eight patients were included in the study, and tumor biopsy was collected for genotyping and immunohistochemical analysis of ERCC1. Sixty-seven patients (62%) received no adjuvant therapy, and the rest had either platinum-based chemotherapy (28.5%), radiotherapy (6.5%) or both treatments (2.8%). Log-rank analysis revealed no significant connection between tumor ERCC1 expression (P = 0.12) or adjuvant therapy (P = 0.56) on patient survival. Also, non-parametric Mann-Whitney analysis showed no significant link between tumor size or nodus tumor formation and ERCC1 presence in patients in the study. Interestingly, C8092A SNP showed significant association with patient survival (P = 0.01), with patients homozygous for the mutant allele showing the most significantly reduced survival (P = 0.04) compared to those homozygous for the dominant allele (CC). Our results provide novel insight into the genotypic variation of patients from Quanzhou, Fujian province China.

Hydrogen sulfide targets EGFR Cys797/Cys798 residues to induce Na(+)/K(+)-ATPase endocytosis and inhibition in renal tubular epithelial cells and increase sodium excretion in chronic salt-loaded rats.

AIMS: The role of hydrogen sulfide (H2S) in renal sodium and water homeostasis is unknown. We investigated whether H2S promoted Na(+)/K(+)-ATPase endocytosis via the H2S/EGFR/gab1/PI3K/Akt pathway in renal tubular epithelial cells. RESULTS: H2S decreased Na(+)/K(+)-ATPase activity and induced its endocytosis in renal tubular epithelial cells, which was abrogated by small interfering RNA (siRNA) knockdown of epidermal growth factor receptor (EGFR) and gab1, a dominant-negative mutant of Akt and PI3K inhibitors. H2S increased EGFR, gab1, PI3K, and Akt phosphorylation in both renal tubular epithelial cells and kidneys of chronic salt-loaded rats. These increases were abrogated by siRNA knockdown of EGFR, but not of c-Src. Radiolabeled H2S exhibited transient, direct binding to EGFR and directly activated EGFR. Some disulfide bonds in EGFR intracellular kinase domain were susceptible to H2S-induced cleavage. Mutations of EGFR Cys797 (human) or Cys798 (rat) residues increased EGFR activity and prevented H2S-induced Na(+)/K(+)-ATPase endocytosis. H2S also inhibited sodium hydrogen exchanger-3 (NHE3) activity in renal tubular epithelial cells. H2S treatment increased sodium excretion in chronic and acute salt-loaded rats and decreased blood pressure in chronic salt-loaded rats. INNOVATION AND CONCLUSION: H2S directly targets some disulfide bonds in EGFR, which activates the EGFR/gab1/PI3K/Akt pathway and subsequent Na(+)/K(+)-ATPase endocytosis and inhibition in renal tubular epithelial cells. EGFR Cys797/Cys798 residues are essential for an intrinsic inhibitory mechanism and for H2S actions in renal tubular epithelial cells. Other pathways, including NHE3, may be involved in mediating the renal effects of H2S. Our results reveal a new renal sodium homeostasis mechanism, which may provide for novel treatment approaches for diseases related to renal sodium homeostasis dysfunction.

VEGFR2 functions as an H2S-targeting receptor protein kinase with its novel Cys1045-Cys1024 disulfide bond serving as a specific molecular switch for hydrogen sulfide actions in vascular endothelial cells.

AIMS: The potential receptor for hydrogen sulfide (H2S) remains unknown. RESULTS: H2S could directly activate vascular endothelial growth factor receptor 2 (VEGFR2) and that a small interfering RNA (siRNA)-mediated knockdown of VEGFR2 inhibited H2S-induced migration of human vascular endothelial cells. H2S promoted angiogenesis in Matrigel plug assay in mice and this effect was attenuated by a VEGF receptor inhibitor. Using tandem mass spectrometry (MS), we identified a new disulfide complex located between Cys1045 and Cys1024 within VEGFR2 that was labile to H2S-mediated modification. Kinase activity of the mutant VEGFR2 (C1045A) devoid of the Cys1045-Cys1024 disulfide bond was significantly higher than wild-type VEGFR2. Transfection with vectors expressing VEGFR2 (C1045A) caused a significant increase in cell migration, while the migration-promoting effect of H2S disappeared in the cells transfected with VEGFR2 (C1045A). Therefore, the Cys1045-Cys1024 disulfide bond serves as an intrinsic inhibitory motif and functions as a molecular switch for H2S. The formation of the Cys1045-Cys1024 disulfide bond disrupted the integrity of the active conformation of VEGFR2. Breaking the Cys1045-Cys1024 disulfide bond recovered the active conformation of VEGFR2. This motif was prone to a nucleophilic attack by H2S via an interaction of their frontier molecular orbitals. siRNA-mediated knockdown of cystathionine γ-lyase attenuated migration of vascular endothelial cells induced by VEGF or moderate hypoxia. INNOVATION AND CONCLUSION: The study provides the first piece of evidence of a molecular switch in H2S-targeting receptor protein kinase in H2S-induced angiogenesis and that may be applicable to additional kinases containing functionally important disulfide bonds in mediating various H2S actions.

Pattern of relapse in surgical treated patients with thoracic esophageal squamous cell carcinoma and its possible impact on target delineation for postoperative radiotherapy.

OBJECTIVE: To provide a reference for determination of the postoperative radiotherapy target volume for thoracic esophageal squamous cell carcinoma. BACKGROUND DATA: The irradiation target volume is important for effective postoperative treatment of thoracic esophageal squamous cell carcinoma. METHODS: One hundred forty patients with recurrent or metastatic thoracic esophageal squamous cell carcinoma who had been treated with radical surgery but not with postoperative radiotherapy were enrolled in this study. The information of locoregional recurrence and distant metastasis for these patients was analyzed. RESULTS: The median time to progression in the 140 patients with recurrence or metastasis was 18.3 months (range 15.4-21.1 months). Anastomotic recurrence accounted for 13.6% of treatment failures. The supraclavicular and station 1-5 and 7 lymph nodes had high metastasis rates for esophageal squamous cell carcinomas in all locations. The order from highest to lowest metastasis rate for the station 3 and 4 lymph nodes was middle, upper and lower thoracic esophageal regions and the order for upper abdominal lymph nodes was lower, middle, and upper thoracic esophageal regions. Locoregional recurrence was the most common type of recurrence. CONCLUSIONS: For upper and middle thoracic esophageal squamous cell carcinomas, the anastomosis, supraclavicular, and station 1-5 and 7 lymph nodes should be delineated as the postoperative prophylactic irradiation target volume with upper abdominal lymph nodes excluded; for lower thoracic esophageal squamous cell carcinomas, anastomosis, supraclavicular, station 1-5 and 7 lymph nodes and upper abdominal lymph nodes should be delineated as the postoperative prophylactic irradiation target volume.

Hydrogen sulfide induces human colon cancer cell proliferation: role of Akt, ERK and p21.

H(2)S (hydrogen sulfide), regarded as the third gaseous transmitter, is implicated in ulcerative colitis and colorectal cancers. The present study investigates the effects of H(2)S on cell proliferation in human colon cancer HCT 116 cells and SW480 cells. We identified the two key enzymes, CBS and CSE, for H(2)S synthesis in HCT 116 cells. An exogenously administered H(2)S donor NaHS induced cell proliferation in a concentration-dependent manner, with optimal proliferative concentration at 200 micromol/l. NaHS administration increased Akt and ERK phosphorylation. Blockade of Akt and ERK activation attenuated NaHS-induced cell proliferation. Cell-cycle analysis showed that NaHS treatment for 6 h decreased the proportion of cells in G(0)-G(1) phase and increased the proportion of cells in S phase. Protein expressions of Cyclin D1 and PCNA (proliferating cell nuclear antigen) were not altered, but the cyclin-dependent kinase inhibitor p21(Waf1/Cip1) was inhibited significantly by NaHS treatment. NaHS significantly reduced NO metabolite levels. In conclusion, NaHS induced human colon cancer cell proliferation. This effect might be mediated by the increase of Akt and ERK phosphorylation and the decrease of p21(Waf1/Cip1) expression and NO production. The results suggested a role for H(2)S in human colonic cancer development.

Mechanisms of angiogenesis: role of hydrogen sulphide.

1. Hydrogen sulphide (H(2)S) has recently been recognized as a gasotransmitter that regulates angiogenesis in vitro and in vivo under physiological and ischaemic conditions. 2. In the present review, the mechanisms underlying angiogenesis are summarized briefly and the most recent progress in H(2)S-induced angiogenesis in vivo and in vitro is described. The anti-angiogenic effects of garlic extracts, which may serve as substrates for H(2)S-generating enzymes in vivo, are also discussed. 3. Hydrogen sulphide increases cell growth, migration and the formation of tube-like structures in cultured endothelial cells. These effects are dependent on activation of the phosphatidylinositol 3-kinase-Akt-survivin signalling pathway. Neovascularization in vivo has also been demonstrated to be promoted in the mouse Matrigel plug assay, as well as in chicken chorioallantoic membranes. In a rat unilateral hindlimb ischaemic model, treatment with sodium hydrosulphide (NaHS), an H(2)S donor, promotes significant angiogenesis and improves regional blood flow. These effects may be mediated by interactions between upregulated vascular endothelial growth factor (VEGF) in skeletal muscle cells and VEGF receptor 2 and the downstream signalling element Akt in vascular endothelial cells. However, H(2)S does not exhibit a pro-angiogenic effect at a high concentrations/doses. 4. Based on the studies reviewed in the present article, we assume that, at physiologically relevant doses/concentrations, H(2)S/HS(-) promote angiogenesis at least partly via the VEGF signalling pathway. At high doses, H(2)S/HS(-) may act on additional cellular targets to evoke mechanisms that counteract the pro-angiogenic pathways. More studies need to be performed analysing the general interactions between H(2)S/HS(-) and other molecules, including other gasotransmitters, such as nitric oxide and carbon monoxide (CO).

The hydrogen sulfide donor NaHS promotes angiogenesis in a rat model of hind limb ischemia.

It is not known whether H(2)S can promote angiogenesis with improvement of regional blood flow in ischemic organs. Sodium hydrosulfide (NaHS, a H(2)S donor) was administered once a day for 4 w following femoral artery ligation. Collateral vessel growth, capillary density, regional tissue blood flow, the expression of endothelial growth factor (VEGF), VEGF receptor 2 (VEGFR2) and Akt were examined during or at the end of the treatment period. NaHS treatment significantly increased collateral vessel growth, capillary density, and regional tissue blood flow in ischemic hind limb muscles compared with the controls. These effects were associated with an increase in VEGF expression in the skeletal muscles and VEGFR2 phosphorylation in the neighboring vascular endothelial cells, suggesting a role of VEGF in mediating the NaHS effects in a cell-cell interaction pattern. Moreover, NaHS treatment also resulted in an increase in Akt phosphorylation in ischemic hind limb muscles. In conclusion, our observations with NaHS strongly suggest that H(2)S is a proangiogenic factor in chronic ischemia. The proangiogenic effect of NaHS may be mediated by interaction between the upregulated VEGF in the skeletal muscle cells and the VEGFR2 as well as its downstream signaling element Akt in the vascular endothelial cells.

The novel proangiogenic effect of hydrogen sulfide is dependent on Akt phosphorylation.

OBJECTIVE: Hydrogen sulfide (H(2)S) has been reported to be a gasotransmitter which regulates cardiovascular homeostasis. The present study aims to examine the hypothesis that hydrogen sulfide is able to promote angiogenesis. METHODS: Angiogenesis was assessed using in vitro parameters (i.e. endothelial cell proliferation, adhesion, transwell migration assay, scratched wound healing and formation of tube-like structure) and in vivo by assessing neovascularization in mice. Phosphorylation of Akt was measured using Western blot analysis. RESULTS: Exogenously administered NaHS (H(2)S donor) concentration-dependently (10-20 micromol/l) increased cell growth, migration, scratched wound healing and tube-like structure formation in cultured endothelial cells. These effects of NaHS on endothelial wound healing and tube-like structure formation were prevented by either the phosphatidylinositol 3-kinase (PI3K) inhibitor LY 294002 (5 micromol/l) or transfection of a dominant-negative mutant of Akt. NaHS increased Akt phosphorylation and this effect was also blocked by either LY 294002 or wortmannin (25 nmol/l). NaHS did not significantly alter the levels of vascular endothelial growth factor, mRNA expression of fibroblast growth factor and angiopoietin-1, or nitric oxide metabolites. NaHS treatment (10 and 50 micromol kg(-1) day(-1)) significantly promoted neovascularization in vivo in mice. CONCLUSION: The present study reports a novel proangiogenic role of H(2)S which is dependent on activation of Akt.

Survivin mediates the anti-apoptotic effect of delta-opioid receptor stimulation in cardiomyocytes.

Survivin is known to be essential for cell division and to inhibit apoptosis during embryonic development and in adult cancerous tissues. However, the cardiovascular role of survivin is unknown. We observed that in cardiomyocytes cultured under conditions of serum and glucose deprivation (DEPV), the levels of survivin, Bcl-2 and extracellular signal-regulated kinase (ERK) were positively correlated with the anti-apoptotic action of a delta-opioid receptor agonist, [D-Ala2, D-Leu5]-enkephalin acetate (DADLE). By contrast, Bax translocation, mitochondrial membrane damage and reactive oxygen species (ROS) production were inversely correlated with the changes of survivin and Bcl-2. The use of RNA interference (RNAi) targeting survivin increased DEPV-induced cardiomyocyte apoptosis, whereas the anti-apoptotic effect of DADLE was blunted by survivin RNAi. Moreover, survivin transfection and overexpression provided protection against DEPV-induced cardiomyocyte apoptosis. Inhibition of ERK prevented the DADLE-induced decrease in apoptosis and Bax translocation, and increase in survivin and Bcl-2. DADLE-induced increase in survivin was also blunted by phosphoinositol 3-kinase (PI 3-kinase) inhibition. In conclusion, the present study provides the first direct evidence of an anti-apoptotic role of survivin mediating the anti-apoptotic effect of delta-opioid receptor activation in cardiomyocytes. ERK and PI 3-kinase were found to be upstream regulators of survivin. Mitochondrial membranes as well as ROS, Bcl-2 and Bax were also involved in this anti-apoptotic action.