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Movahed Rad, Pouya, et al.
(författare)
Endogenous unsaturated C18 N-acylethanolamines are vanilloid receptor (TRPV1) agonists.
2005
Ingår i: Journal of Biological Chemistry. - 1083-351X .- 0021-9258. ; 280:46, s. 38496-38504
Tidskriftsartikel (refereegranskat) abstract
The endogenous C18 N-acylethanolamines (NAEs) N-linolenoylethanolamine (18:3 NAE), N-linoleoylethanolamine (18:2 NAE), N-oleoylethanolamine (18:1 NAE), and N-stearoylethanolamine (18:0 NAE) are structurally related to the endocannabinoid anandamide (20:4 NAE), but these lipids are poor ligands at cannabinoid CB1 receptors. Anandamide is also an activator of the transient receptor potential (TRP) vanilloid 1 (TRPV1) on primary sensory neurons. Here we show that C18 NAEs are present in rat sensory ganglia and vascular tissue. With the exception of 18:3 NAE in rat sensory ganglia, the levels of C18 NAEs are equal to or substantially exceed those of anandamide. At submicromolar concentrations, 18:3 NAE, 18:2 NAE, and 18:1 NAE, but not 18:0 NAE and oleic acid, activate native rTRPV1 on perivascular sensory nerves. 18:1 NAE does not activate these nerves in TRPV1 gene knock-out mice. Only the unsaturated C18 NAEs elicit whole cell currents and fluorometric calcium responses in HEK293 cells expressing hTRPV1. Molecular modeling revealed a low energy cluster of U-shaped unsaturated NAE conformers, sharing several pharmacophoric elements with capsaicin. Furthermore, one of the two major low energy conformational families of anandamide also overlaps with the cannabinoid CB1 receptor ligand HU210, which is in line with anandamide being a dual activator of TRPV1 and the cannabinoid CB1 receptor. This study shows that several endogenous non-cannabinoid NAEs, many of which are more abundant than anandamide in rat tissues, activate TRPV1 and thus may play a role as endogenous TRPV1 modulators.
4.
Vincents, Bjarne, et al.
(författare)
Down-regulation of human extracellular cysteine protease inhibitors by the secreted staphylococcal cysteine proteases, staphopain A and B.
2007
Ingår i: Biological Chemistry. - 1437-4315. ; 388:4, s. 437-446
Tidskriftsartikel (refereegranskat) abstract
Of seven human cystatins investigated, none inhibited the cysteine proteases staphopain A and B secreted by the human pathogen Staphylococcus aureus. Rather, the extracellular cystatins C, D and E/M were hydrolyzed by both staphopains. Based on MALDI-TOF time-course experiments, staphopain A cleavage of cystatin C and D should be physiologically relevant and occur upon S. aureus infection. Staphopain A hydrolyzed the Glyl 1 bond of cystatin C and the Ala10 bond of cystatin D with similar K-m values of approximately 33 and 32 mu m, respectively. Such N-terminal truncation of cystatin C caused > 300-fold lower inhibition of papain, cathepsin B, L and K, whereas the cathepsin H activity was compromised by a factor of ca. 10. Similarly, truncation of cystatin D caused alleviated inhibition of all endogenous target enzymes investigated. The normal activity of the cystatins is thus down-regulated, indicating that the bacterial enzymes can cause disturbance of the host protease-inhibitor balance. To illustrate the in vivo consequences, a mixed cystatin C assay showed release of cathepsin B activity in the presence of staphopain A. Results presented for the specificity of staphopains when interacting with cystatins as natural protein substrates could aid in the development of therapeutic agents directed toward these proteolytic virulence factors.
5.
Brage, M, et al.
(författare)
Different cysteine proteinases involved in bone resorption and osteoclast formation.
2005
Ingår i: Calcified tissue international. - : Springer Science and Business Media LLC. - 0171-967X .- 1432-0827. ; 76:6, s. 439-47
Tidskriftsartikel (refereegranskat) abstract
Cysteine proteinases, especially cathepsin K, play an important role in osteoclastic degradation of bone matrix proteins and the process can, consequently, be significantly inhibited by cysteine proteinase inhibitors. We have recently reported that cystatin C and other cysteine proteinase inhibitors also reduce osteoclast formation. However, it is not known which cysteine proteinase(s) are involved in osteoclast differentiation. In the present study, we compared the relative potencies of cystatins C and D as inhibitors of bone resorption in cultured mouse calvariae, osteoclastogenesis in mouse bone marrow cultures, and cathepsin K activity. Inhibition of cathepsin K activity was assessed by determining equilibrium constants for inhibitor complexes in fluorogenic substrate assays. The data demonstrate that whereas human cystatins C and D are equipotent as inhibitors of bone resorption, cystatin D is 10-fold less potent as an inhibitor of osteoclastogenesis and 200-fold less potent as an inhibitor of cathepsin K activity. A recombinant human cystatin C variant with Gly substitutions for residues Arg8, Leu9, Val10, and Trp106 did not inhibit bone resorption, had 1,000-fold decreased inhibitory effect on cathepsin K activity compared to wildtype cystatin C, but was equipotent with wildtype cystatin C as an inhibitor of osteoclastogenesis. It is concluded that (i) different cysteine proteinases are likely to be involved in bone resorption and osteoclast formation, (ii) cathepsin K may not be an exclusive target enzyme in any of the two systems, and (iii) the enzyme(s) involved in osteoclastogenesis might not be a typical papain-like cysteine proteinase.
6.
Gomez-Pinilla, Pedro J, et al.
(författare)
Melatonin restores impaired contractility in aged guinea pig urinary bladder
2008
Ingår i: Journal of Pineal Research. - : Blackwell Publishing Ltd. - 1600-079X .- 0742-3098. ; 44:4, s. 416-425
Tidskriftsartikel (refereegranskat) abstract
Urinary bladder disturbances are frequent in the elderly population but the responsible mechanisms are poorly understood. This study evaluates the effects of aging on detrusor myogenic contractile responses and the impact of melatonin treatment. The contractility of bladder strips from adult, aged and melatonin-treated guinea pigs was evaluated by isometric tension recordings. Cytoplasmatic calcium concentration ([Ca2+](i)) was estimated by epifluorescence microscopy of fura-2-loaded isolated detrusor smooth muscle cells, and the levels of protein expression and phosphorylation were quantitated by Western blotting. Aging impairs the contractile response of detrusor strips to cholinergic and purinergic agonists and to membrane depolarization. The impaired contractility correlates with increased [Ca2+](i) in response to the stimuli, suggesting a reduced Ca(2+)sensitivity. Indeed, the agonist-induced contractions in adult strips were sensitive to blockade with Y27362, an inhibitor of Rho kinase (ROCK) and GF109203X, an inhibitor of protein kinase C (PKC), but these inhibitors had negligible effects in aged strips. The reduced Ca2+ sensitivity in aged tissues correlated with lower levels of RhoA, ROCK, PKC and the two effectors CPI-17 and MYPT1, and with the absence of CPI-17 and MYPT1 phosphorylation in response to agonists. Interestingly, melatonin treatment restored impaired contractility via normalization of Ca2+ handling and Ca2+ sensitizations pathways. Moreover, the indoleamine restored age-induced changes in oxidative stress and mitochondrial polarity. These results suggest that melatonin might be a novel therapeutic tool to palliate aging-related urinary bladder contractile impairment.
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Magnusson, Marie, et al.
(författare)
A placebo-controlled study of retinal blood flow changes by pentoxifylline and metabolites in humans
2006
Ingår i: British Journal of Clinical Pharmacology. - : Wiley. - 0306-5251 .- 1365-2125. ; 61:2, s. 138-147
Tidskriftsartikel (refereegranskat) abstract
AIM: To investigate the possible effects of pentoxifylline metabolites on retinal blood flow in humans. METHODS: A randomized, placebo-controlled, four-period cross-over study that was observer blinded and partly blinded for the eight participants. On one occasion a placebo was given as an intravenous (i.v.) infusion over 100 min. On the other three occasions pentoxifylline was administered as i.v. infusions over 100 min at a rate of 3 mg min(-1). Before two of the pentoxifylline infusions the subjects were pretreated with either ciprofloxacin or rifampicin. Retinal blood flow was measured by scanning laser doppler flowmetry (SLDF) in a selected area of the central temporal retina before, during and until 5 h after the end of infusion. Blood samples for concentration analyses of pentoxifyllin, R-M1, S-M1, M4 and M5 were taken serially and areas under the curves (AUCs) were calculated. Linear mixed models were used for the statistical analyses. RESULTS: Mean AUCs (ng h ml(-1)) were significantly increased for pentoxifylline (1964 vs. 1453) and S-M1 (5804 vs. 4227), but not R-M1 when pentoxifylline was co-administered with ciprofloxacin. The mean AUC for M5 was significantly reduced when subjects were pretreated with rifampicin (2041 vs. 3080). Pentoxifylline with and without pretreatment with rifampicin significantly increased retinal blood flow assessed as mean flow, pulsation (i.e. 1-systole/diastole), and diastolic flow (but not during systole), compared with placebo. The increases over placebo were more pronounced on diastolic flow, 9.7% (95% confidence interval 4.2, 15.5) than on mean flow, 4.6% (1.1, 8.3) after pentoxifylline administration. With pentoxifylline after rifampicin pretreatment the corresponding differences were 11.7% (5.8, 17.9) and 5.1% (1.4, 7.8) over placebo, respectively. After co-administration of pentoxifylline and ciprofloxacin we saw only a nonsignificant trend towards increased flow during diastole, but a significant decrease in pulsation. When AUCs for pentoxifylline and its metabolites were used as regressor variables to retinal mean flow we found that pentoxifylline, R-M1 and M5 had coefficients with a positive sign indicating that they enhanced the retinal blood flow. In contrast, S-M1 and M4 had coefficients with negative sign and thus appeared to decrease the blood flow in subjects treated with pentoxifylline. CONCLUSION: The R-M1 and M5 metabolites of pentoxifylline contributed significantly to the effects of pentoxifylline on retinal blood flow.
9.
Rhodin, Malin M., et al.
(författare)
Human renal function maturation : a quantitative description using weight and postmenstrual age
2009
Ingår i: Pediatric nephrology (Berlin, West). - : Springer Science and Business Media LLC. - 0931-041X .- 1432-198X. ; 24:1, s. 67-76
Tidskriftsartikel (refereegranskat) abstract
This study pools published data to describe the increase in glomerular filtration rate (GFR) from very premature neonates to young adults. The data comprises measured GFR (using polyfructose, Cr-51-EDTA, mannitol or iohexol) from eight studies (n=923) and involved very premature neonates (22 weeks postmenstrual age) to adulthood (31 years). A nonlinear mixed effects approach (NONMEM) was used to examine the influences of size and maturation on renal function. Size was the primary covariate, and GFR was standardized for a body weight of 70 kg using an allometric power model. Postmenstrual age (PMA) was a better descriptor of maturational changes than postnatal age (PNA). A sigmoid hyperbolic model described the nonlinear relationship between GFR maturation and PMA. Assuming an allometric coefficient of 3/4, the fully mature (adult) GFR is predicted to be 121.2 mL/min per 70 kg [95% confidence interval (CI) 117-125]. Half of the adult value is reached at 47.7 post-menstrual weeks (95% CI 45.1-50.5), with a Hill coefficient of 3.40 (95% CI 3.03-3.80). At 1-year postnatal age, the GFR is predicted to be 90% of the adult GFR. Glomerular filtration rate can be predicted with a consistent relationship from early prematurity to adulthood. We propose that this offers a clinically useful definition of renal function in children and young adults that is independent of the predictable changes associated with age and size.
10.
van West, Dirk, et al.
(författare)
Glucocorticoid receptor gene-based SNP analysis in patients with recurrent major depression
2006
Ingår i: Neuropsychopharmacology. - : Nature Publishing Group. - 0893-133X .- 1740-634X. ; 31:3, s. 620-627
Tidskriftsartikel (refereegranskat) abstract
Dysregulation of the hypothalamic-pituitary-adrenal axis, one of the stress-response systems, is one of the key neurobiological features of major depression (MDD). Data supporting the notion that glucocorticoid-mediated feedback inhibition is impaired in MDD come from a multitude of studies demonstrating nonsuppression of cortisol secretion following administration of the synthetic glucocorticoid dexamethasone. We examined whether genetic variations in the glucocorticoid receptor gene (Nuclear Receptor Subfamily 3, Group C, Member 1; NR3C1) could be associated with increased susceptibility for MDD using a whole gene-based association analysis of single nucleotide polymorphisms (SNPs). Four SNPs were identified in NR3C1 and genotyped in two well-diagnosed samples of patients with MDD ascertained in Belgium and northern Sweden, and matched control samples. In total, 314 MDD patients and 354 control individuals were included in the study. In the Belgian sample, we observed significant allele (p=0.02) and genotype (p=0.02) association with an SNP in the promoter region (NR3C1-1); in the Swedish sample, we observed significant allele (p=0.02) and genotype (p=0.02) association with the R23K SNP. The haplotype association studies showed modest evidence for an involvement of the 5' region of the NR3C1 gene in the genetic vulnerability for MDD. This study suggests that polymorphisms in the 5' region of the NR3C1 gene may play a role in the genetic vulnerability for MDD.
