Effect of reactive oxygen species on capacitation and associated protein tyrosine phosphorylation in buffalo (Bubalus bubalis) spermatozoa

2008 ◽  
Vol 107 (1-2) ◽  
pp. 68-84 ◽  
Author(s):  
S.C. Roy ◽  
S.K. Atreja
1993 ◽  
Vol 295 (3) ◽  
pp. 879-888 ◽  
Author(s):  
U Zor ◽  
E Ferber ◽  
P Gergely ◽  
K Szücs ◽  
V Dombrádi ◽  
...  

We have previously shown that vanadate potentiates the activating effect of phorbol ester (TPA) on cellular phospholipase A2 (PLA2) in a pathway dependent on the formation of reactive oxygen species (ROS). Here we evaluate the chain of enzymes (protein kinases and phosphatases) that participate in this process. Treatment of macrophages with vanadate plus TPA led to activation of protein kinase C (PKC) and NADPH oxidase (O2- generation in intact cells), massive cellular protein tyrosine phosphorylation, suppression of protein tyrosine phosphatase (PTP) activity and a sustained activation of protein tyrosine kinase (PTK) and myelin basic protein kinase activity (the latter three enzyme activities were assessed in cell lysates). Inhibition of ROS formation by diphenyleneiodonium (DPI) prevented PTP inhibition, PTK activation and protein tyrosine phosphorylation by vanadate plus TPA. Vanadate plus H2O2 mimicked the effect of vanadate plus TPA on PKC activation, cellular protein tyrosine phosphorylation, PTP and PTK, but their effects were resistant to DPI. Suppression of PKC activity (down-regulation; selective inhibitors) prevented the above-mentioned effects of vanadate plus TPA, but not of vanadate plus H2O2. Collectively, the results show that ROS formation induced by TPA in association with vanadate is essential in the modulation of protein tyrosine phosphorylation and PLA2 activity.


2003 ◽  
Vol 285 (6) ◽  
pp. H2336-H2344 ◽  
Author(s):  
Matthias Maas ◽  
Ronggang Wang ◽  
Cathy Paddock ◽  
Srigiridhar Kotamraju ◽  
Balaraman Kalyanaraman ◽  
...  

Platelet endothelial cell adhesion molecule-1 (PECAM-1, CD31) functions to control the activation and survival of the cells on which it is expressed. Many of the regulatory functions of PECAM-1 are dependent on its tyrosine phosphorylation and subsequent recruitment of the Src homology (SH2) domain containing protein tyrosine phosphatase SHP-2. The recent demonstration that PECAM-1 tyrosine phosphorylation occurs in cells exposed to the reactive oxygen species hydrogen peroxide (H2O2) suggested that this form of oxidative stress may also support PECAM-1/SHP-2 complex formation. In the present study, we show that PECAM-1 tyrosine phosphorylation in response to exposure of cells to H2O2 is reversible, involves a shift in the balance between kinase and phosphatase activities, and supports binding of SHP-2 and recruitment of this phosphatase to cell-cell borders. We speculate, however, that the unique ability of H2O2 to reversibly oxidize the reactive site cysteine residues of protein tyrosine phosphatases may result in transient inactivation of the SHP-2 that is bound to PECAM-1 under these conditions. Finally, we provide evidence that PECAM-1 tyrosine phosphorylation and SHP-2 binding in endothelial cells requires exposure to an “oxidative burst” of H2O2, but that exposure of these cells to sufficiently high concentrations of H2O2 for a sufficiently long period of time abrogates binding of SHP-2 to tyrosine-phosphorylated PECAM-1. These findings support a role for PECAM-1 as a sensor of oxidative stress, perhaps most importantly during the process of inflammation.


Author(s):  
Mojdeh Hosseinpoor Kashani ◽  
Mina Ramezani ◽  
Zeinab Piravar

Background: Acrylamide (AA) is a reactive molecule produced during food processing at temperatures above 120°C. Objective: To evaluate the impact of different concentrations of AA on human sperm parameters, oxidative stress and total antioxidant capacity (TAC). Materials and Methods: In this laboratory study, semen samples were obtained from healthy donors referred to the Taleghani Hospital, Tehran, Iran between June and July 2019. Samples were divided into four groups (n = 10/each): one control and three treatment groups (0.5, 1, and 2 mM of AA). After 2 hr of exposure to AA, the superoxide dismutase and malondialdehyde levels were measured based on colorimetric methods. The TAC was determined by the ferric-reducing antioxidant power assay. Flow cytometry was performed to measure the intracellular reactive oxygen species generation. Also, immunohistochemistry was done to determine the effect of AA on tyrosine phosphorylation and carboxymethyl-lysine expression. Results: Results of the study demonstrated that the motility and viability of spermatozoa were significantly decreased after AA exposure (p < 0.001). This decrease was also seen in the TAC and superoxide dismutase activity as well as in the phosphotyrosine percentage compared with the control (p < 0.01). However, the carboxymethyllysine and prooxidant activity including reactive oxygen species generation and lipid peroxidation level increased (p < 0.001). Conclusion: Overall, the results confirmed the detrimental effect of AA on human spermatozoa which may be due to oxidative stress and decreased total antioxidant levels. AA may reduce fertility by reducing sperm capacitation and motility. Key words: Acrylamide, Oxidative stress, Antioxidant, Spermatozoa, Infertility.


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