Roles of kisspeptin in IVF/ICSI-treated infertile women and in human granulosa cells

Kisspeptin, a crucial central regulator of reproduction, has been used as a trigger in in vitro fertilization (IVF) treatment. This study aimed to investigate the roles of kisspeptin in IVF treatment in infertile females (n = 30); and in steroidogenesis in human granulosa-like tumor cell line (KGN). In the human study, blood was collected at three time points including (1) the beginning of gonadotropin stimulation (Phase I), (2) around eight days after gonadotropin stimulation (Phase II), and (3) on the day of ovum pick-up (Phase III). Follicular fluid (FF) was collected at Phase III. Serum human chorionic gonadotropin (hCG) was measured 15 days after embryo transfer and fetal heart beats were determined around 42 days of menstrual cycle to classify the subjects into successful and unsuccessful groups. FF kisspeptin levels were higher in successful compared with unsuccessful subjects (P < 0.01). Kisspeptin levels were significantly higher in FF than in serum in successful subjects (P < 0.05) but were comparable in unsuccessful subjects. Serum kisspeptin was comparable among three phases in the successful group but its levels in Phase III were significantly lower compared with Phase I in the unsuccessful group (P < 0.01). Serum kisspeptin in Phase II/III had positive correlations with serum E2 in Phases II and III and the outcomes of IVF/intracytoplasmic sperm injection (ICSI) treatment including serum hCG levels. For the cell experiment (n = 3), kisspeptin treatment in the presence of FSH together with IGF-1 enhanced CYP19A1 (aromatase) mRNA expression compared with control. FSH alone increased aromatase concentrations in the supernatant compared with control and kisspeptin at the dose of 10^-2 mmol/L with FSH enhanced aromatase concentrations in the supernatant compared with FSH alone (P < 0.001 all). In conclusion, kisspeptin enhanced aromatase expression and secretion and was associated with positive outcomes of IVF/ICSI treatment. Further studies regarding supplementation of kisspeptin could reveal its beneficial effects on IVF/ICSI treatment.     

Stimulation of peroxisomal palmitoyl-CoA oxidase activity by ciprofibrate in hepatic cell lines: Comparative studies in Fao,MH1C1 and HepG2 cells

Summary— The response of two rat cell lines, Fao and MH₁C₁, and one human cell line, HepG2, to the peroxisome proliferator ciprofibrate, was studied. Using a fluorometric assay for palmitoyl-CoA oxidase, the dose- and time-dependent increase of this enzymatic activity was determined. From the lowest concentration (100 μM) stimulation is evident in the two rat cell lines. In the Fao line, the activity was stimulated reaching a seven-fold increase over the control level at 250 μM after 72 h of treatment. In the MH₁C₁ line, the maximum stimulation, four- to five-fold, was obtained at 250 and 500 μM after 72 h. In the HepG2 cell line, activity increased two-fold at 250 μM after 72 h reaching a three-fold increase at 1000 μM after 48 h. Ciprofibrate was more toxic to Fao cells than to MH₁C₁ and HepG2 cells which is also the order of the acyl-CoA oxidase stimulation by ciprofibrate. These preliminary results suggest that the two rat cell lines are appropriate for investigating the induction of peroxisomal β-oxidation enzymes and the expression of their genes. The HepG2 cell line is a complementary model for the study of interspecies differences in the response to peroxisomal proliferators and of the peroxisomal functions implied in the lipid metabolism of human liver.     

Optimization of PAHs Oxidation from a Concentrate of Soil Attrition Using Potassium Permanganate

The treatment of soils contaminated with organic compounds, such as polycyclic aromatic hydrocarbons (PAHs), by attrition produced large amounts of highly concentrated attrition sludge (PAH – attrition concentrate – PAC). This paper studied the performance of an oxidation process using potassium permanganate (KMnO₄) to degrade PAHs that were initially present in attrition concentrates. The influence of operating conditions (temperature, concentration of KMnO₄ and reaction time) was studied, and these parameters were optimized using a response surface methodology (RSM). The results showed that the temperature and the reaction time had a significant and positive effect on the degradation of PAHs for the experimental domain studied (temperature between 20 and 60°C and reaction time between 1 and 7 h). The interaction between the temperature and the concentration of KMnO₄ significantly influenced the degradation of the PAHs. The temperature and the concentration of KMnO₄ were the main parameters that influenced the degradation of both phenanthrene (Phe) and benzo [a] pyrene (BaP). For benzo [a] anthracene (BaA), the temperature was the most influential factor. According to our results, the optimal conditions were defined as [KMnO₄] = 0.4 M for 5.5 h at 60°C. These optimal conditions led to degradations of 42.9%, 40.8%, 41.0% and 46.0% of the total PAHs, Phe, BaA and BaP, respectively.     

Phosphorylation of Bem2p and Bem3p may contribute to local activation of Cdc42p at bud emergence

Site-specific activation of the Rho-type GTPase Cdc42p is critical for the establishment of cell polarity. Here we investigated the role and regulation of the GTPase-activating enzymes (GAPs) Bem2p and Bem3p for Cdc42p activation and actin polarization at bud emergence in Saccharomyces cerevisiae. Bem2p and Bem3p are localized throughout the cytoplasm and the cell cortex in unbudded G1 cells, but accumulate at sites of polarization after bud emergence. Inactivation of Bem2p results in hyperactivation of Cdc42p and polarization toward multiple sites. Bem2p and Bem3p are hyperphosphorylated at bud emergence most likely by the Cdc28p-Cln2p kinase. This phosphorylation appears to inhibit their GAP activity in vivo, as non-phosphorylatable Bem3p mutants are hyperactive and interfere with Cdc42p activation. Taken together, our results indicate that Bem2p and Bem3p may function as global inhibitors of Cdc42p activation during G1, and their inactivation by the Cdc28p/Cln kinase contributes to site-specific activation of Cdc42p at bud emergence.     

Functional characterization of FTDP-17 tau gene mutations through their effects on Xenopus oocyte maturation.

tau gene mutations cause frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17). Here we have used Xenopus oocyte maturation as an indicator of microtubule function. We show that wild-type four-repeat Tau protein inhibits maturation in a concentration-dependent manner, whereas three-repeat Tau has no effect. Of the seven four-repeat Tau proteins with FTDP-17 mutations tested, five (G272V, DeltaK280, P301L, P301S, and V337M) failed to interfere significantly with oocyte maturation, demonstrating a greatly reduced ability to interact with microtubules. One mutant protein (R406W) almost behaved like wild-type Tau, and one (S305N) inhibited maturation more strongly than wild-type Tau. With the exception of R406W, wild-type Tau and all the mutants studied were similarly phosphorylated during the Xenopus oocyte maturation, and this was independent of their effects on this process. Data obtained with R406W and S305N may be related to charge changes (phosphorylation and basic amino acids). Our results demonstrate variable effects of FTDP-17 mutations on microtubules in an intact cell situation. Those findings establish Xenopus oocyte maturation as a system allowing the study of the functional effects of tau gene mutations in a quantitative manner.     

Piezo1‐dependent stretch‐activated channels are inhibited by Polycystin‐2 in renal tubular epithelial cells

Mechanical forces associated with fluid flow and/or circumferential stretch are sensed by renal epithelial cells and contribute to both adaptive or disease states. Non‐selective stretch‐activated ion channels (SACs), characterized by a lack of inactivation and a remarkably slow deactivation, are active at the basolateral side of renal proximal convoluted tubules. Knockdown of Piezo1 strongly reduces SAC activity in proximal convoluted tubule epithelial cells. Similarly, overexpression of Polycystin‐2 (PC2) or, to a greater extent its pathogenic mutant PC2‐740X, impairs native SACs. Moreover, PC2 inhibits exogenous Piezo1 SAC activity. PC2 coimmunoprecipitates with Piezo1 and deletion of its N‐terminal domain prevents both this interaction and inhibition of SAC activity. These findings indicate that renal SACs depend on Piezo1, but are critically conditioned by PC2.     

Evolution of liver antioxidant status and iron implication during the development of deoxycorticosterone-saline hypertension in rats

Hypertension is known to be associated with an oxidative stress resulting from an imbalance of antioxidant defense mechanisms in various tissues. The purpose of this study was to investigate the relationship between the increase of arterial blood pressure, measured during the gradual development of experimental hypertension in deoxycorticosterone (DOCA)-salt-treated rats, and an early imbalance of liver antioxidant status. The levels of liver oxidant/antioxidant markers and iron were studied during the induction of hypertension in 3-, 6-, and 8-wk DOCA-salt-treated Sprague-Dawley rats. Hepatic antioxidant defenses were decreased as early as 3 wk of hypertensive treatment: the decrease of peroxidase-reductase-transferase and catalase activities was associated with a significant increase of thiobarbituric acid reactive substances (TBARS) levels. Liver oxidative stress increased until 6 wk, and remained stable at 8 wk of DOCA-salt treatment. Concurrently, liver iron levels were increased at 6 wk and returned to normal values after 8 wk of hypertensive treatment. Iron seems to be an inductor of liver oxidative stress and responsible for the persistent oxidative stress, most likely through secondary free-radical release. Thus, our data (1) confirm that hypertension in DOCA-salt-treated rats might be a free-radical-dependent disease where hepatic oxidant/antioxidant imbalance is obviously involved from the beginning of blood pressure elevation and (2) suggest that the use of suitable iron chelators might reverse liver oxidative stress associated with the increase of blood pressure.     

First synthesis of thia steroids from cholic acid

Heterosteroids remain interesting due to their potential biological activities. This prompted us to synthesize novel thia steroids possessing the heteroatom in the A-ring. We set out to describe a new and versatile method for preparing 3-thia steroids from cholic acid via a selective oxidation of one hydroxyl group, a Baeyer-Villiger oxidation and a photolysis as the key steps. The characteristic ¹H and ¹³C NMR spectroscopic features of the synthesized compounds are reported.     

Mitochondrial long chain fatty acid β-oxidation in man and mouse

Several mouse models for mitochondrial fatty acid β-oxidation (FAO) defects have been developed. So far, these models have contributed little to our current understanding of the pathophysiology. The objective of this study was to explore differences between murine and human FAO. Using a combination of analytical, biochemical and molecular methods, we compared fibroblasts of long chain acyl-CoA dehydrogenase knockout (LCAD^−/−), very long chain acyl-CoA dehydrogenase knockout (VLCAD^−/−) and wild type mice with fibroblasts of VLCAD-deficient patients and human controls. We show that in mice, LCAD and VLCAD have overlapping and distinct roles in FAO. The absence of VLCAD is apparently fully compensated, whereas LCAD deficiency is not. LCAD plays an essential role in the oxidation of unsaturated fatty acids such as oleic acid, but seems redundant in the oxidation of saturated fatty acids. In strong contrast, LCAD is neither detectable at the mRNA level nor at the protein level in men, making VLCAD indispensable in FAO. Our findings open new avenues to employ the existing mouse models to study the pathophysiology of human FAO defects.