BACKGROUND: In this study, the putative interactions between apoptosis and heat shock proteins disturbed as a result of ATP depletion were investigated as a hypoxia model. METHODS: The direct cellular damages were assessed by the release of LDH from the cytoplasm of the human tubular epithelial cells (HK-2 cells) following ATP depletion. The Bcl-2/Bax mRNA expression ratio, used as an index to assess to what extent apoptosis contributed to tubular cell damage, and the expressions of HSP 90, 72 and 27 in relation to the Bcl-2/Bax ratio in the ischemic model, as parameters of their functional contributions to tubule cell damage, were also studied. Heat preconditioning (HS) was performed at 43 degrees in a temperature-regulated water bath for 1 h. RESULTS: The release of LDH due to ATP depletion was not significantly increased in HK-2 cells compared to the control, but was slightly increased in heat preconditioned cells compared to non heat preconditioned cells, but the difference was not statistically significant (6.33 +/- 0.57 U/L vs. 8.67 +/- 2.52 U/L, p> 0.05). The Bcl-2/ Bax mRNA expression ratio increased progressively from the control to the heat preconditioned and ATP depleted cells (control; 100%, ATP depletion; 154 +/- 6%, heat preconditioning; 212 +/- 6%, heat preconditioning and ATP depletion; 421 +/- 8%). No contribution of heat preconditioning and ATP depletion was observed on the expressions of HSP90 and HSP27. However, HSP72 expression was prominent by ATP depletion, especially after heat preconditioning. CONCLUSION: There may be a possibility that the preservation of cytolytic damage and an increase in the Bcl-2/Bax mRNA expression ratio is related to the increase of HSP72 in ATP depletion as a hypoxia model.
Adenosine Triphosphate/*deficiency ; Anoxia/metabolism ; Epithelium/*metabolism ; Heat-Shock Proteins/*metabolism ; Humans ; Kidney Tubules/cytology/*metabolism ; L-Lactate Dehydrogenase/metabolism ; RNA, Messenger/metabolism ; Research Support, Non-U.S. Gov't

OBJECTIVETo investigate the toxic effect of environmental neurotoxin MPP+ to C. elegans and identify the mechanisms that cause the toxicity.

METHODSHuman alpha-synuclein transgenic C. elegans was used as the animal model, the toxic effect of MPP+ to dopamine (DA) neurons and the lifespan of worms was tested. The worms were feed with OP50 to determine whether ATP increase can rescue the worm from toxicity. ATP level and aberrant protein accumulation were analyzed in the MPP+ treated worms with or without OP50 addition.

RESULTSWe found that MPP+ induced DA cell death and worm lethality, which could be prevented by OP50 treatment. OP50 exerted the protective effect by up-regulating ATP level, even though it also induced accumulation of alpha-synuclein. Despite the undefined role of protein aggregation to the cell death, our results showed that the toxicity of MPP+ was mainly caused by the ATP depletion in the alpha-synuclein transgenic C. elegans.

CONCLUSIONMPP+ could induce DA neuronal death and worm lethality in alpha-synuclein transgenic C. elegans; Compared with the aggregation of alpha-synuclein, the major cause of MPP+ toxicity appeared due to ATP depletion.

1-Methyl-4-phenylpyridinium ; toxicity ; Adenosine Triphosphate ; deficiency ; metabolism ; Animals ; Animals, Genetically Modified ; Caenorhabditis elegans ; Caenorhabditis elegans Proteins ; drug effects ; metabolism ; Cell Death ; Disease Models, Animal ; Dopamine ; metabolism ; Herbicides ; toxicity ; Humans ; MPTP Poisoning ; metabolism ; mortality ; Neurons ; drug effects ; metabolism ; alpha-Synuclein ; drug effects ; genetics ; metabolism

Vitamin D deficiency is a common health issue around the world. We therefore evaluated the associations of semen quality with both serum and seminal plasma vitamin D levels and studied the mechanisms underlying these by incubating spermatozoa with 1,25(OH)₂D In vitro. Two hundred and twenty-two men were included in our study. Vitamin D was detected using an electrochemiluminescence method. Spermatozoa used for In vitro experiments were isolated by density gradient centrifugation. Positive relationships of serum 25(OH)D with semen volume and seminal plasma fructose were identified. Seminal plasma 25(OH)D level showed no relationship with serum 25(OH)D level, while it was inversely associated with sperm concentration and positively correlated with semen volume and sperm kinetic values. In vitro, sperm kinetic parameters increased after incubation with 1,25(OH)₂D, especially upon incubation for 30 min with it at a concentration of 0.1 nmol l^-1. Under these incubation conditions, the upward migration of spermatozoa increased remarkably with increasing adenosine triphosphate (ATP) concentration. The concentration of cyclic adenosine monophosphate (cAMP) and the activity of protein kinase A (PKA) were both elevated, and the PKA inhibitor, N-[2-(p-Bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide dihydrochloride (H89) reversed the increase of ATP production. The concentrations of cytoplasmic calcium ions and nicotinamide adenine dinucleotide (NADH) were both enhanced, while mitochondrial calcium uniporter (MCU) inhibitor, Ruthenium 360 (Ru360) did not reverse the increase of ATP production. Therefore, seminal plasma vitamin D may be involved in regulating sperm motility, and 1,25(OH)₂D may enhance sperm motility by promoting the synthesis of ATP both through the cAMP/PKA pathway and the increase in intracellular calcium ions.
Adenosine Triphosphate/metabolism* ; Adult ; Calcium/metabolism* ; Cyclic AMP/metabolism* ; Cyclic AMP-Dependent Protein Kinases/metabolism* ; Humans ; Male ; Semen/metabolism* ; Semen Analysis ; Signal Transduction/physiology* ; Sperm Motility/physiology* ; Spermatozoa/metabolism* ; Vitamin D/pharmacology* ; Vitamin D Deficiency/blood* ; Wit and Humor as Topic ; Young Adult