ABSTRACT
BACKGROUND: Hydrogen sulfide (H2S) is one of the endogenous gaseous molecules promoting the production of nitric oxide (NO) which has cardioprotective functions. However, the role of the H2S-mediated protein S-nitrosoproteome and its subsequent physiological response remains unclear. METHODS: Endothelial cells EAhy 926 were treated with 50 µM of H2S for 2 hours. The NO bound S-nitrosoproteins were purified by a biotin-switch and then digested by trypsin. Resulting peptides from control and H2S treatment were separately labeled by isobaric tag for relative and absolute quantitation 114/115, quantified by liquid chromatography tandem-mass spectrometry and analyzed by ingenuity pathway analysis (IPA) software. The microP software was applied to analyze the morphological changes of mitochondria. RESULTS: With the treatment of H2S, 416 S-nitrosylated proteins were identified. IPA analysis showed that these proteins were involved in five signaling pathways. The NO-bound cysteine residues and the S-nitrosylation levels (115/114) were shown for ten S-nitrosoproteins. Western blot further verified the S-nitrosylation of thioredoxin-dependant peroxide reductase, cytochrome c oxidase and cytochrome b-c1 complex that are involved in the mitochondrial signaling pathway. H2O2-induced mitochondrial swelling can be reduced by the pretreatment of H2S. CONCLUSIONS: The H2S-mediated endothelial S-nitrosoproteome has been confirmed. In the present study, we have proposed the cardioprotective role of H2S via maintaining mitochondrial homeostasis.
ABSTRACT
OBJECTIVE: Drinking ice water is a common daily activity. The safety of ice water ingestion has been questioned due to its possible deleterious effect on heart rate or cardiac rhythm, especially in patients with acute myocardial infarction. Thus, we investigated the heart rate variability (HRV) before and after ice water ingestion in normal subjects to delineate the possible effect of ice water ingestion on autonomic nervous modulation. METHODS: Subjects were volunteers who came to the hospital to receive routine health examination. They were randomly assigned to drinking 250 ml of ice water or room temperature water. Twenty-eight subjects in the room temperature water ingestion group and 25 subjects in the ice water ingestion group were studied. The relationships between the change in HRV measures before and after water ingestion and clinical parameters were assessed by correlation analysis. RESULTS: After ice water ingestion, the percentage change in mean RR intervals (RRIs) (4 ± 4 vs. -1 ± 4, P < 0.001), standard deviation of RRIs (19 ± 35 vs. 0 ± 21, P = 0.018), high-frequency power (64 ± 90 vs. -3 ± 41, P < 0.001), and normalized high-frequency power (39 ± 99 vs. -5 ± 31, P = 0.038) were higher, while the percentage change in low-/high-frequency power ratio (3 ± 92 vs. 44 ± 97, P = 0.017) was lower, when compared with those after the room temperature water ingestion. INTERPRETATION: Ice water ingestion can decrease heart rate through temperature stimulus-mediated vagal enhancement in healthy subjects.