Transcriptome, metabolome and suppressor analysis reveal an essential role for the ubiquitin-proteasome system in seedling chloroplast development.

BACKGROUND: Many regulatory circuits in plants contain steps of targeted proteolysis, with the ubiquitin proteasome system (UPS) as the mediator of these proteolytic events. In order to decrease ubiquitin-dependent proteolysis, we inducibly expressed a ubiquitin variant with Arg at position 48 instead of Lys (ubK48R). This variant acts as an inhibitor of proteolysis via the UPS, and allowed us to uncover processes that are particularly sensitive to UPS perturbation. RESULTS: Expression of ubK48R during germination leads to seedling death. We analyzed the seedling transcriptome, proteome and metabolome 24 h post ubK48R induction and confirmed defects in chloroplast development. We found that mutations in single genes can suppress seedling lethality, indicating that a single process in seedlings is critically sensitive to decreased performance of the UPS. Suppressor mutations in phototropin 2 (PHOT2) suggest that a contribution of PHOT2 to chloroplast protection is compromised by proteolysis inhibition. CONCLUSIONS: Overall, the results reveal protein turnover as an integral part of a signal transduction chain that protects chloroplasts during development.

Efficacy and safety of vardenafil for the treatment of erectile dysfunction in men with metabolic syndrome: results of a randomized, placebo-controlled trial.

INTRODUCTION: The prevalence of erectile dysfunction (ED) is increased in men with metabolic syndrome compared with the general population. AIM: The aim of this study was to evaluate the efficacy and safety of vardenafil vs. placebo in men who had ED and metabolic syndrome. METHODS: This was a 12-week, double-blind, randomized, multicenter, parallel-group, placebo-controlled prospective study in men with ED and metabolic syndrome (assessed by the International Diabetes Federation criteria). Vardenafil was administered at a starting dose of 10 mg, which could be titrated to 5 mg or 20 mg after 4 weeks, depending on efficacy and tolerability. MAIN OUTCOME MEASURES: Primary efficacy measures were the erectile function domain of the International Index of Erectile Function (IIEF-EF) and Sexual Encounter Profile (SEP) diary questions 2/3. Secondary efficacy measures included SEP1, a diary question assessing ejaculation, the percentage of men achieving "return-to-normal" erectile function, and the percentage of men who titrated to a different dose. Adverse events (AEs) were recorded throughout the study. RESULTS: The intent-to-treat population included 145 men (vardenafil, N = 75; placebo, N = 70). Baseline least squares IIEF-EF domain scores were low (vardenafil: 12.0; placebo: 12.7), indicative of moderate-to-severe ED. Vardenafil was statistically significantly superior to placebo for all primary efficacy measures (P < 0.0001) and showed nominally statistically significant superiority compared with placebo for SEP1/ejaculation success rates (P = 0.0003 and P < 0.0001, respectively) and the percentage of subjects reporting "return-to-normal" erectile function (P = 0.0004). Treatment-emergent AEs were mild-to-moderate in severity and consistent with the known AE profile of phosphodiesterase type 5 inhibitors. CONCLUSIONS: This is the first study to assess the efficacy and safety of vardenafil, taken alone, for ED therapy in a population of men who all had metabolic syndrome. Although baseline erectile function in these patients was low, vardenafil treatment was associated with significant improvements in erectile function and rates of successful intercourse, and was well tolerated.

Lack of major involvement of human uroplakin genes in vesicoureteral reflux: implications for disease heterogeneity.

BACKGROUND: Primary vesicoureteral reflux (VUR) is a hereditary disorder characterized by the retrograde flow of urine into the ureters and kidneys. It affects about 1% of the young children and is thus one of the most common hereditary diseases. Its associated nephropathy is an important cause of end-stage renal failure in children and adults. Recent studies indicate that genetic ablation of mouse uroplakin (UP) III gene, which encodes a 47 kD urothelial-specific integral membrane protein forming urothelial plaques, causes VUR and hydronephrosis. METHODS: To begin to determine whether mutations in UP genes might play a role in human VUR, we genotyped all four UP genes in 76 patients with radiologically proven primary VUR by polymerase chain reaction (PCR) amplification and sequencing of all their exons plus 50 to 150 bp of flanking intronic sequences. RESULTS: Eighteen single nucleotide polymorphisms (SNPs) were identified, seven of which were missense, with no truncation or frame shift mutations. Since healthy relatives of the VUR probands are not reliable negative controls for VUR, we used a population of 90 race-matched, healthy individuals, unrelated to the VUR patients, as controls to perform an association study. Most of the SNPs were not found to be significantly associated with VUR. However, SNP1 of UP Ia gene affecting a C to T conversion and an Ala7Val change, and SNP7 of UP III affecting a C to G conversion and a Pro154Ala change, were marginally associated with VUR (both P= 0.08). Studies of additional cases yielded a second set of data that, in combination with the first set, confirmed a weak association of UP III SNP7 in VUR (P= 0.036 adjusted for both subsets of cases vs. controls). CONCLUSION: Such a weak association and the lack of families with simple dominant Mendelian inheritance suggest that missense changes of uroplakin genes cannot play a dominant role in causing VUR in humans, although they may be weak risk factors contributing to a complex polygenic disease. The fact that no truncation or frame shift mutations have been found in any of the VUR patients, coupled with our recent finding that some breeding pairs of UP III knockout mice yield litters that show not only VUR, but also severe hydronephrosis and neonatal death, raises the possibility that major uroplakin mutations could be embryonically or postnatally lethal in humans.

Organ-specificity in a plant disease is determined independently of R gene signaling.

The molecular basis of organ specificity in plant diseases is little characterized. Downy mildew of Arabidopsis caused by the oomycete Hyaloperonospora parasitica (formerly Peronospora parasitica) is characteristically a leaf disease. Resistant host genotypes recognize the pathogen in a gene-for-gene dependent manner and respond with the production of H2O2 and the execution of a genetically programmed hypersensitive cell death (HR). We inoculated the roots of Arabidopsis genotypes Col-0, Ws-0, and Wei-0 with the NOCO and WELA races of the pathogen and compared the responses with those observed in leaves. Combinations of incompatible genotypes of host and pathogen showed the expected responses of an oxidative burst and the HR in leaves, but surprisingly, roots showed no signs of active defense and appeared completely susceptible to all the H. parasitica isolates tested. Reverse transcriptase-polymerase chain reaction showed that the R gene RPP1, which mediates resistance in leaves of accession Ws-0 to the H. parasitica isolate NOCO, was expressed in leaves as well as in roots. Similarly, NDR1 and EDS1, two components of R gene-mediated signaling pathways, are also expressed in both tissues. To our knowledge, it has not been previously demonstrated that expression of R genes and downstream components of the signaling cascade are not sufficient for the induction of avirulence gene-mediated defense mechanisms in roots.