Effect Of Hypotaurine Research Articles

Hamster spermatozoa incorporate hypotaurine via TauT for self-protection.

Mammalian spermatozoa actively generate reactive oxygen species (ROS) during capacitation, a maturational process necessary for fertilization in vivo. This study shows that hypotaurine, a precursor of taurine present in the oviduct, is incorporated and concentrated in hamster sperm cells via the taurine transporter, TauT, for cytoprotection against self-produced ROS. To achieve fertilization competence, mammalian spermatozoa undergo capacitation, during which they actively generate reactive oxygen species (ROS). Therefore, mammalian spermatozoa must protect themselves from these self-generated ROS. The mammalian oviductal fluid is rich in hypotaurine, a taurine precursor, which reportedly protects mammalian spermatozoa, including those of hamsters, from ROS; however, its precise mechanism remains unknown. This study aimed to elucidate the mechanism underlying hypotaurine-mediated protection of spermatozoa from ROS using hamsters, particularly focusing on the taurine/hypotaurine transporter TauT. The effect of hypotaurine on sperm motility and ROS levels was tested using sperm motility analysis and the CellROX dye and luminol assays. RNA sequencing analysis was performed to verify TauT expression. We found that hypotaurine was necessary for maintaining sperm motility and hyperactivated motility. Hypotaurine did not scavenge extracellular ROS but lowered intracellular ROS levels and was incorporated and concentrated in hamster spermatozoa. TauT was detected at both mRNA and protein levels. β-Alanine blocked hypotaurine transport, increased intracellular ROS levels, and inhibited hyperactivation. Elimination of Na+ or Cl- ions inhibited hypotaurine transport and increased intracellular ROS levels. Thus, these results indicated that hamster spermatozoa incorporated and concentrated hypotaurine in sperm cells via TauT to protect themselves from self-generated ROS.

Effects of Hypotaurine on the Activity and Conformation Polyphenol Oxidase in Penaeus vannamei

Effects of Hypotaurine on the Activity and Conformation Polyphenol Oxidase in Penaeus vannamei

Carbonate Anion Radical Generated by the Peroxidase Activity of Copper-Zinc Superoxide Dismutase: Scavenging of Radical and Protection of Enzyme by Hypotaurine and Cysteine Sulfinic Acid.

Copper-zinc superoxide dismutase (SOD) is considered one of the most important mammalian antioxidant defenses and plays a relevant role due to its main function in catalyzing the dismutation of superoxide anion to oxygen and hydrogen peroxide. However, interaction between SOD and H2O2 produced a strong copper-bound oxidant (Cu(II)•OH) that seems able to contrast the self-inactivation of the enzyme or oxidize other molecules through its peroxidase activity. The bicarbonate presence enhances the peroxidase activity and produces the carbonate anion radical (CO3•-). CO3•- is a freely diffusible reactive species capable of oxidizing several molecules that are unwieldy to access into the reactive site of the enzyme. Cu(II)•OH oxidizes bicarbonate to the CO3•-, which spreads out of the binding site and oxidizes hypotaurine and cysteine sulfinic acid to the respective sulfonates through an efficient reaction. These findings suggest a defense role for sulfinates against the damage caused by CO3•- . The effect of hypotaurine and cysteine sulfinic acid on the CO3•--mediated oxidation of the peroxidase probe ABTS to ABTS cation radical (ABTS•+) has been studied. Both sulfinates are able to inhibit the oxidation of ABTS mediated by CO3•-. The effect of hypotaurine and cysteine sulfinic acid against SOD inactivation by H2O2 (~42% protection of enzyme activity) has also been investigated. Interestingly, hypotaurine and cysteine sulfinic acid partially avoid the H2O2-mediated SOD inactivation, suggesting that the two sulfinates may have access to the SOD reactive site and preserve it by reacting with the copper-bound oxidant. In this way hypotaurine and cysteine sulfinic acid not only intercept CO3•- which could move out from the reactive site and cause oxidative damage, but also prevents the inactivation of SOD.

PP02 - Effects of hypotaurine on carbonate radical anion and nitrogen dioxide radical generated by peroxidase activity of Cu,Zn-superoxide dismutase

PP02 - Effects of hypotaurine on carbonate radical anion and nitrogen dioxide radical generated by peroxidase activity of Cu,Zn-superoxide dismutase

Effects of Hypotaurine, Cysteamine, and Aminoacids Solution on Post-Thaw Microscopic and Oxidative Stress Parameters of Angora Goat Semen.

Effects of Hypotaurine, Cysteamine, and Aminoacids Solution on Post-Thaw Microscopic and Oxidative Stress Parameters of Angora Goat Semen.

Effects of hypotaurine, cysteamine and aminoacids solution on post-thaw microscopic and oxidative stress parameters of Angora goat semen

This study was conducted to determine the effects of cysteamine, hypotaurine and aminoacids solution (BME) on standard semen parameters, lipid peroxidation and antioxidant activities of Angora goat semen after the freeze–thawing process. Ejaculates collected from four Angora goats were evaluated and pooled at 37 °C. Semen samples, which were diluted with a Tris-based extender containing the antioxidants hypotaurine (5 mM) and cysteamine (5 mM), and an aminoacid solution (13%), and an extender containing no antioxidants (control), were cooled to 5 °C and frozen in 0.25-ml French straws in liquid nitrogen. Frozen straws were thawed individually at 37 °C for 20 s in a water bath for evaluation. Supplementation with cysteamine, hypotaurine and BME caused significant ( P < 0.05) increases in sperm motility, and significant ( P < 0.05) decreases in total abnormality rates in comparison to the control group. While all in vitro treatments did not affect the acrosomal abnormality rates, hypotaurine and BME but not cysteamine significantly ( P < 0.05) increased the HOST results as compared to the control group. Supplementation with antioxidants and BME did not significantly affect MDA levels and CAT activity in comparison to the control group ( P > 0.05). The antioxidants hypotaurine and cysteamine decreased SOD activity when compared to the BME group and controls ( P < 0.001).

The protective effect of hypotaurine and cysteine sulphinic acid on peroxynitrite-mediated oxidative reactions

The protective activity of hypotaurine (HTAU) and cysteine sulphinic acid (CSA) on peroxynitrite-mediated oxidative damage has been assessed by monitoring different target molecules, i.e. tyrosine, dihydrorhodamine-123 (DHR) and glutathione (GSH). The inhibition of tyrosine oxidation exerted by HTAU and CSA both in the presence and the absence of bicarbonate can be ascribed to their ability to scavenge hydroxyl (•OH) and carbonate (CO3•−) radicals. HTAU and CSA also reduce tyrosyl radicals, suggesting that this repair function of sulphinates might operate as an additional inhibiting mechanism of tyrosine oxidation. In the peroxynitrite-dependent oxidation of DHR, the inhibitory effect of HTAU was lower than that of CSA. Moreover, while HTAU and CSA competitively inhibited the direct oxidation of GSH by peroxynitrite, HTAU was again poorly effective against the oxidation of GSH mediated by peroxynitrite-derived radicals. The possible involvement of secondary reactions, which could explain the difference in antioxidant activity of HTAU and CSA, is discussed.

Effect of hypotaurine on development of in vitro-derived bovine embryos

High birth weights were observed in calves that developed from bovine embryos produced by in vitro maturation (IVM) and in vitro fertilization (IVF) procedures. After IVM and IVF, embryos were either co-cultured in vitro with oviductal epithelial cells or transferred into the sheep oviduct for development to the blastocyst stage. Blastocysts were transferred to the reproductive tracts of recipient heifers and cows for development to term. Birth weights and gestation periods were compared between calves that developed from in vitro-derived embryos and calves born after artificial insemination (AI) of cows in the herd from which recipient females were selected. Gestation periods were not different among the groups (P > 0.05), but calves that developed from IVM/IVF-derived embryos co-cultured in vitro were larger at birth than calves born from IVM/IVF-derived embryos that developed into blastocysts in the sheep oviduct and calves born from AI (P < 0.001). Dystocia and calf mortality were associated with large calf size at birth. These data were collected from an experiment designed for other purposes, and confounding variables and small sample size could have influenced the observed differences in birth weights. Nevertheless, the extreme birth weights of some calves suggest that abnormal prenatal growth occurs in some IVM/IVF-derived bovine embryos and that conditions for co-culture to the blastocyst stage may exacerbate the problem.

Effect of Hypotaurine in Fertilization Medium on Fertilization of In Vitro Matured Bovine Oocytes and Their Subsequent Development

In Experimental 1, when in vitro matured (IVM) bovine oocytes were inseminated with frozen-thawed spermatozoa in in-vitro fertilization (IVF) medium (BO solution containing 5 μg/ml heparin) (Control) and IVF medium supplemented with 5 mM caffeine (Caf) or 10 mM hypotaurine (HT) for 1, 3 and 5 h, significantly higher percentages of oocytes were penetrated in Caf and HT groups than Control group after 3 h of insemination. Then the rates showed no difference between groups after 5 h of insemination. However, a significantly lower percentage of monospermic oocytes was obtained in Caf group than Control and HT groups. In Experimental 2, IVM oocytes were inseminated with spermatozoa in IVF medium supplememted with 0, 1, 5 and 10 mM HT, and then co-cultured with cumulus cells in TCM 199 with 5% calf serum. There was no difference in the ability of spermatozoa to penetrate oocytes between groups but significantly higher rates of fusion of male and female pro nuclei in monospermic oocytes were obtained in the medium supplemented with 10 mM HT than no addition.The addition of HT in IVF medium significantly improved percentages of embryos developed to the stage of blastocyst. In Experimental 3, IVM oocytes were inseminated in IVF medium supplemented with 10 mM HT or 5 mM Caf and then co-cultured as described in Exp.2. significantly higher percentages of monospermic oocytes and embryos developed to the stage of blastocyst were obtained with HT groups than Caf group. In monospermic oocytes significantly higher rates of fusion of male and female pro nuclei were obtained in HT group than Caf group. These results indicate that addition of HT in the ferti lization medium promotes monospermic fertilization compared with Caf and shortens the duration of insemination needed for spermatozoa to penetrate oocytes resulting in higher percentages of IVM/IVF oocytes develop to the stage of blastocyst than those of no addition.

Effect of hypotaurine on in vitro fertilization and production of term offspring from in vitro-fertilized ova of the Japanese field vole, Microtus montebelli.

The present study was proposed to establish new in vitro fertilization (IVF)-embryo transfer techniques for wild mammals. We demonstrated that IVF of the Japanese field vole, Microtus montebelli, is improved by hypotaurine, and that IVF vole embryos can develop to normal offspring after transfer to recipient females. The rate of IVF was significantly increased when 0.1 or 1 mM of hypotaurine was added during sperm preincubation and fertilization (p < 0.05). Preincubation of spermatozoa with 1 mM hypotaurine prior to oocyte insemination did not have a significant effect on fertilization rate (p < 0.01). At 96 h after insemination, most cultured embryos developed to the 2-cell stage (68-83%), but development to blastocysts was very low (0-3%) for all treatments. Although 43 living offspring were produced after transfer of IVF pronuclear embryos to recipients, the delivery rate of recipients was very low (21%). The litter size of pseudopregnant recipients that produced a litter was 4-11, and the rate of in vivo development of transferred embryos in the pregnant recipients was 41%. These results suggest that hypotaurine affects IVF rather than sperm preincubation and that IVF embryos can develop to normal offspring.

Addition of hypotaurine can reactivate immotile golden hamster spermatozoa.

Hamster epididymal spermatozoa became virtually immotile following washing and dilution in chemically defined medium (TLP-PVA). The sperm motility factors (penicillamine, hypotaurine, and epinephrine: PHE) were examined for their ability to reactivate immotile sperm. Sperm could be reactivated by addition of PHE at 1 h of incubation. Hypotaurine alone was capable of reactivating sperm motility, but epinephrine and penicillamine together were not. However, overall sperm motility and percentage of motile sperm during incubation were higher when PHE components were used in combination than when hypotaurine was used alone. Addition of hypotaurine to immotile sperm suspensions could be postponed for up to 6 h with subsequent recovery of sperm motility, although the degree of recovery of motility declined progressively with each hour that addition of hypotaurine was delayed. The rescuing effect of hypotaurine was due to an increase both in the percentage of motile sperm and in the quality (grade) of sperm motility. The data show that hypotaurine is required for expression of sperm motility in the hamster, and support the concept that the loss of hypotaurine from sperm following washing and dilution is responsible for the sperm-immobilizing effect of these procedures. Additionally, the data demonstrate that hamster sperm can remain viable for several hours after becoming immotile, and that many of the immotile sperm are capable of being reactivated.

The Influence of Hypotaurine on Taurine Transport in Isolated Renal Cortex Tubules

SummaryThe effect of hypotaurine on taurine transport in isolated tubules from rat renal cortex was examined at the low Km (10 μM) and the high Km (2 mM) system. Taurine transport is inhibited at both sites, but hypotaurine appears to inhibit accumulation on the high Km system to a greater extent. The effect is competitive and hypotaurine has greater affinity for the taurine uptake system than does β-alanine. Finally, hypotaurine is shown to interact with the taurine carrier so that exchange diffusion is observed.