11β-hydroxysteroid dehydrogenase type 1, brain atrophy and cognitive decline

Excess cortisol levels are linked with brain atrophy and cognitive decline in older people. 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) potently amplifies intracellular glucocorticoid action by converting inert cortisone to active cortisol, but any causal importance in brain aging is unexplored. We tested the hypotheses that higher systemic 11β-HSD1 activity predicts brain atrophy and cognitive decline in older men. In a longitudinal study of 41 men (65-70 years old at baseline) we measured baseline systemic 11β-HSD1 activity, the urinary 5alpha- and 5beta-tetrahydrocortisol to tetrahydrocortisone ratio (ratio of tetrahydrometabolites of cortisol (THFs)/ratio of tetrahydrometabolites of cortisol (THE)), and assessed change in brain atrophy, white matter lesions and cognitive function over 6 years. Baseline THFs/THE correlated negatively with baseline hippocampal volumes (left: r = -0.37; right: r = -0.34; p < 0.05) and positively with ventricular volumes (r = 0.43, p = 0.006) and periventricular white matter lesions (rho = 0.31, p = 0.047). Importantly, baseline THFs/THE but not cortisol predicted increase in ventricular volumes (r = 0.33, p = 0.037) and decline in processing speed (r = -0.55, p = 0.0002) over 6 years. The predictive link between systemic 11β-HSD1 activity and progressive brain atrophy and cognitive decline suggests 11β-HSD1 inhibition as a plausible therapy for brain aging.     

Activity of 11β-hydroxysteroid dehydrogenase in tissues of hypertensive NISAG rats

11β-Hydroxysteroid dehydrogenase activity in the kidneys of NISAG rats (rat strain with hereditary stress-induced arterial hypertension) was 1.5-fold higher than in WAG rats. An inverse relationship was observed in the liver of these animals. After stress exposure 11β-hydroxysteroid dehydrogenase activity remained unchanged in the kidneys of NISAG and WAG rats, but significantly increased in the liver of NISAG rats. Functional activity of 11β-hydroxysteroid dehydrogenase probably reflects the hypertensive state of NISAG rats. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 141, No. 1, pp. 35–37, January, 2006     

Intense physical exercise increases systemic 11β-hydroxysteroid dehydrogenase type 1 activity in healthy adult subjects

Intense physical exercise activates the hypothalamic–pituitary–adrenocortical axis but little is known about changes in glucocorticoid sensitivity at the target cell level. No data are available on the acute effects of exercise on 11β-hydroxysteroid dehydrogenase (11β-HSD) type 1 activity, which generates biologically active cortisol from inactive cortisone and is expressed also in skeletal muscle. Fifteen healthy, trained males (age mean ± SE 28 ± 1) were assessed on three non-consecutive days: at rest, during an endurance and strength sessions. During each session, between 1000 and 1600 hours, 6-h urine and four salivary samples were collected. Urinary total tetrahydrocortisol (THF) + alloTHF, tetrahydrocortisone (THE), cortisol (F) and cortisone (E) were measured with HPLC-tandem mass spectrometry; urinary-unconjugated F and E were measured by HPLC-UV. Salivary cortisol and interleukin (IL)-6 were measured by RIA and ELISA, respectively. Both endurance and strength exercises caused an increase in (THF + alloTHF)/THE ratio (mean ± SE 1.90 ± 0.07 and 1.82 ± 0.05 vs. 1.63 ± 0.06, P < 0.01 and P = 0.03, respectively), consistent with increased systemic 11β-HSD type 1 activity. No relationship was found with age, BMI, $ V{{{\text{O}}_{2\max } }} , $ maximal power load or perceived exertion. No significant change was apparent in F/E ratio, an index of 11β-HSD type 2 activity. No effect of exercise on salivary cortisol and IL-6 was observed, whereas a significant effect of sampling time was found. Intense physical exercise acutely increases systemic 11β-HSD type 1 activity in humans. Such an increase may lead to higher cortisol concentration in target tissues, notably in skeletal muscle where it could contribute to limit exercise-induced muscle inflammatory response.     

Comparative pharmacokinetics and metabolism studies in lean and diet- induced obese mice: an animal efficacy model for 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) inhibitors

Diet-induced obese (DIO) mice have been commonly used as an animal model in the efficacy assessment for new drug candidates. Although high-fat feeding has been reported to cause profound physiological changes, including the expression of drug-metabolizing enzymes, limited studies have been reported regarding the effect of obesity/diabetes on pharmacokinetics (PK) in animals. In this study, we investigated PK profiles of three 11 -HSD-1 inhibitors in the DIO mice and compared them to the normal lean mice. After oral administration, the in vivo exposure (AUC) of all three compounds was higher in DIO mice, which was consistent with the observed lower systemic clearance (CL) in DIO mice compared to lean mice. As illustrated by Compound E, a compound metabolized predominantly by CYP3A and 2C, the metabolic profiles for Compound E were qualitatively similar between DIO and lean mice, but quantitatively lower in the DIO mice. Indeed, P-450 activities for CYP3A and 2C as well as 2D were found to be lower in liver microsomes prepared from DIO mice. The calculated hepatic clearance (CLH) from in vitro studies with liver microsomes correlated well with the observed in vivo clearance for both DIO and lean mice. The calculated oral bioavailability (F%) based on intrinsic hepatic clearance (C(LH, int)) predicted ~3 fold increase in F% for the DIO mice, which was comparable to the observed value. Collectively, these data suggest that the higher F% is most likely due to the lower first-pass effect in DIO mice. This study highlights the needs to take caution when extrapolating PK and exposure data from healthy animals to diseased animals in designing pharmacological studies.     

Immunohistochemical analysis of 17β-hydroxysteroid dehydrogenase isozymes in human ovarian surface epithelium and epithelial ovarian carcinoma

Epidemiological studies have indicated a relationship between gonadal steroid hormones, primarily estrogens, and epithelial ovarian carcinoma. In situ estrogen metabolism and synthesis have been considered to play important roles in the development of the progression of epithelial ovarian carcinoma. 17β-Hydroxysteroid dehydrogenases (17β-HSDs) are a group of intracellular isozymes catalyzing interconversions between estradiol (E2) and estrone (E1). In the last step of steroidogenesis, 17β-HSD type 1 catalyzes the 17β-reduction and produces E2 from E1. The oxidative enzymes known as types 2, 4, and 8 are potent estrogen-inactivating enzymes that convert E2 to E1. Here we report the immunoexpression of 17β-HSD types 1, 2, 4, and 8 in normal human ovarian surface epithelium (OSE) and epithelial ovarian carcinoma. For this study, novel polyclonal antibodies were generated against each type of 17β-HSD. Of the six normal OSE cases investigated, 17β-HSD types 1, 4, and 8, but not type 2, were found in the cytoplasm of epithelial cells. In 58 cases of epithelial ovarian carcinoma (45 serous, 4 endometrioid, 4 mucinous, and 5 clear cell), estrogen-inactivating 17β-HSDs were commonly found (type 2, 84.5%; type 4, 82.8%; type 8, 86.2%), whereas type 1 was detected in only 10 cases (17.2%). These results indicate that 17β-HSDs may be involved in the protective and/or suppressive effects against the estrogen-dependent proliferation of epithelial ovarian carcinoma.     

Chemical synthesis, characterisation and biological evaluation of furanic-estradiol derivatives as inhibitors of 17β-hydroxysteroid dehydrogenase type 1

Local biosynthesis of estrogens, especially estradiol (E2), is thought to be important for the maintenance and growth of estrogen-sensitive diseases. To control E2 formation, we have investigated a series of epoxide and furanic E2 derivatives as inhibitors of 17β-hydroxysteroid dehydrogenase type 1 (17β-HSD1), the enzyme responsible for the conversion of estrone (E1) into E2. We report here a strategy to synthesize a series of E2-furanic derivatives from E1. An intermediate epoxide was first obtained and then reduced to give a furanic steroid, which allowed us to introduce a molecular diversity like alcohol, bromide, ester, acid and amide. The inhibition of the transformation of [(14)C]-E1 (100 nM) into [(14)C]-E2 by these compounds was first evaluated with homogenated HEK-293 cells overexpressing 17β-HSD1. The epoxide and butylamide derivatives showed the best inhibitions with 72% and 66%, respectively, at 10 μM. All furanic compounds showed a lower 17β-HSD1 inhibitory potency in intact T47-D breast cancer cells than in homogenated cells, but a great improvement of the inhibitory activity was observed for the epoxide, which gave 62% and 90% of inhibition of the [(14)C]-E1 (60 nM) into [(14)C]-E2 transformation at 1 and 10 μM, respectively.     

Immunohistochemical localization and biological activity of 3β-hydroxysteroid dehydrogenase and 5α-reductase in the brain of the frog,Rana esculenta,during development

The occurrence of several enzymes responsible for the biosynthesis of neurosteroids in the brain of adult frogs is now firmly established but the expression of these enzymes during ontogenesis has not yet been investigated. In the present report, we describe the immunohistochemical distribution and biological activity of 3β-hydroxysteroid dehydrogenase (3β-HSD) and 5α-reductase (5α-R) in the brain of the European green frog, Rana esculenta, during larval development. The spatio-temporal distribution of 3β-HSD and 5α-R immunoreactivities in the tadpole brain was generally different, although these two enzymes were occasionally detected in the same areas such as the olfactory bulbs and cerebellum. Identification of neurons based on their morphological aspect as well as labeling of astrocytes with an antiserum against glial fibrillary acidic protein (GFAP) revealed that, in the tadpole brain, 3β-HSD- and 5α-R-immunoreactive materials were contained in both neurons and glial cells. Incubation of tadpole brain explants with [³H]-pregnenolone resulted in the formation of several tritiated steroids including progesterone, 17-hydroxyprogesterone, androstenedione, 5α-dihydroprogesterone and 5α-dihydrotestosterone. The present study provides the first immunocytochemical mapping of two key steroidogenic enzymes in the developing frog brain. The data also indicate that neurosteroid biosynthesis occurs in the brain of tadpoles, as previously shown for adult amphibians, birds and mammals. The transient expression of steroidogenic enzymes in several regions of the tadpole brain suggests that, in amphibians, neurosteroids may be implicated in neurotrophic activities during larval development.     

Isoproterenol and GTPγS inhibit L-type calcium channels of differentiating rat skeletal muscle cells

Summary In adult skeletal muscle, G-proteins have been shown to modulate the calcium channels both directly and through a cAMP-dependent phosphorylating mechanism. We have investigated the action of G-proteins on the L-type calcium current in cultured rat muscle cells (myoballs) under voltage clamp in whole cell or perforated patch modes. Intracellular photolytic release of 200 M GTPS inhibited the L-type calcium current. Inclusion of 500 M uncaged GTPS in the patch pipette in the whole cell configuration reduced the calcium current by a similar amount. Under perforated patch conditions external application of 10 M of the -adrenergic agonist isoproterenol also reduced the calcium current. Pretreatment of the cells with pertussis toxin reversed the effect of GTPS and removed that of isoproterenol. We conclude that rat myoballs contain -adrenergic receptors that inhibit the L-type calcium current, and that this inhibition is mediated by a pertussis toxinsensitive G-protein.     

Rotavirus-neutralizing antibodies inhibit virus binding to integrins α2β1 and α4β1

Summary Rotavirus outer capsid proteins VP5^*, VP8^* and VP7 elicit neutralizing, protective antibodies. The α2β1 integrin is a cellular receptor for rotavirus that is bound by VP5^*. Some rotaviruses also recognize the α4β1 integrin. In this study, the effects of antibodies to rotavirus on virus binding to recombinant α2β1 and α4β1 expressed on K562 cells were determined. All neutralizing monoclonal antibodies to VP5^* tested (YO-2C2, 2G4, 1A10) and two to VP7 (RV-3:2, RV-4:2) inhibited rotavirus binding to α2β1. Rotavirus binding to α4β1 was reduced by 2G4 and neutralizing antibody F45:2, directed to VP7. However, a neutralizing antibody to VP8^* (RV-5:2) and one to VP7 (RV-3:1) did not affect rotavirus binding to these integrins. Virus-cell binding was unaffected by non-neutralizing antibody RVA to the rotavirus inner capsid protein VP6. The attachment of human rotavirus strain Wa to these integrins was inhibited by infection sera with neutralizing activity collected from two children hospitalised with severe rotavirus gastroenteritis. A negative reference serum did not affect rotavirus-cell attachment. As the binding of rotaviruses to α2β1 and α4β1 is inhibited by neutralizing antibodies to VP5^* and VP7, and serum from children with rotavirus disease, rotavirus recognition of these integrins may be important for host infection.     

X-inactivation of HSD17B10 revealed by cDNA analysis in two female patients with 17β-hydroxysteroid dehydrogenase 10 deficiency

17β-Hydroxysteroid dehydrogenase 10 (HSD10) is a mitochondrial enzyme involved in the degradation pathway of isoleucine and branched-chain fatty acids. The gene encoding HSD10, HSD17B10, has been reported as one of the few genes that escapes X-inactivation. We previously studied two female patients with HSD10 deficiency, one of them was severely affected and the other presented a mild phenotype. To elucidate as to why these two carriers were so differently affected, cDNA analyses were performed. The HSD17B10 cDNA of eight control cell lines, two hemizygous patients and two carriers was obtained from cultured fibroblasts, amplified by PCR and sequenced by standard methods. All HSD17B10 cDNAs were quantified by real-time PCR. In the fibroblasts of the female patient who presented with the severe phenotype, only the mutant allele was identified in the cDNA sequence, which was further confirmed by relative quantification (RQ) of HSD17B10 cDNA. This is in agreement with an unfavourable X-inactivation. The other female patient, with slight clinical affectation, showed the presence of both mutant and wild-type alleles in the cDNA sequence, which was confirmed by RQ of HSD17B10 cDNA in fibroblasts. This is in line with normal X-inactivation and the expression of both alleles in different cells (functional mosaicism). RQ results of HSD17B10 cDNA did not differ significantly between male and female controls, which indicate that the genetic doses of mRNA of HSD17B10 was the same in both sexes. In conclusion, these results suggest that the HSD17B10 gene does not escape X-inactivation as has been reported previously.     

Mediastinal adipose tissue expresses a pathogenic profile of 11 β-hydroxysteroid dehydrogenase Type 1, glucocorticoid receptor,and CD68 in patients with coronary artery disease

ObjectiveCardiac visceral fat is accepted to be a new marker for cardiometabolic risk due to its association with increased cardiovascular risk factors. This study aimed to compare the expression of 11 beta hydroxysteroid dehydrogenases (11β-HSD)-1, glucocorticoid receptor (GCR), and CD68 in mediastinal and subcutaneous adipose tissues (MAT, and SAT, respectively) and to assess their possible relationships with the development of coronary artery disease (CAD).Methods and resultsExpression of 11β-HSD-1, GCR, and CD68 mRNA levels were measured by quantitative real-time polymerase chain reaction in MAT and SAT tissues of 37 patients undergoing coronary artery bypass grafting due to CAD (CAD group) and 19 non-CAD patients (controls) undergoing heart valve surgery. 11β-HSD-1 in MAT and SAT and GCR expression in MAT and SAT were found to be significantly increased in CAD group when compared with controls (P<.05, respectively). In CAD group, 11β-HSD-1 mRNA levels were found to be significantly higher in MAT compared to SAT (P<.05). CD68 mRNA levels were significantly higher in MAT of CAD group compared to controls (P<.05). Immunohistochemical analyses demonstrated the presence of CD68+ cells and increased 11β-HSD-1 expression in MAT of CAD group compared to SAT.ConclusionThe present study demonstrate that the mediastinal fat exhibits a pathogenic mRNA profile of 11β-HSD-1, GCR, and CD68. The identification of 11β-HSD-1 expression within the mediastinal fat, along with increased GCR expressions and the presence of CD68+ cells highlight that MAT potentially contributes to the pathogenesis of CAD.     

Immunohistochemical localisation of 3β-hydroxysteroid dehydrogenase in<Emphasis Type="Italic"> Sarcocystis</Emphasis> spp.

3-Hydroxysteroid-dehydrogenase (3-HSD) is an isoenzyme that catalyses an essential step in the synthesis of all classes of active steroid hormones. The presence of steroid hormones of the vertebrate type in invertebrates is acknowledged in addition to a group of steroid-like hormones called ecdysteroids that were present in arthropods and helminths. In the present study, 3-HSD was detected in the bradyzoites enclosed in sarcocysts of Sarcocystis spp. with immunohistochemistry. The results suggest that self-originating steroid hormones may play important roles in the development of Sarcocystis spp., and possibly in the regulation of the reciprocal immune interaction between the host and these parasites.