Reductase Type Research Articles

Function of the evolutionarily conserved plant methionine-S-sulfoxide reductase without thecatalytic residue.

In plants, two types of methionine sulfoxide reductase (MSR) exist, namely methionine-S-sulfoxide reductase (MSRA) and methionine-R-sulfoxide reductase (MSRB). These enzymes catalyze the reduction of methionine sulfoxides (MetO) back to methionine (Met) by a catalytic cysteine (Cys) and one or two resolving Cys residues. Interestingly, a group of MSRA encoded by plant genomes does not have a catalytic residue. We asked that if this group of MSRA did not have any function (as fitness), why it was not lost during the evolutionary process. To challenge this question, we analyzed the gene family encoding MSRA in soybean (GmMSRAs). We found seven genes encoding GmMSRAs, which included three segmental duplicated pairs. Among them, a pair of duplicated genes, namely GmMSRA1 and GmMSRA6, was without a catalytic Cys residue. Pseudogenes were ruled out astheir transcripts were detected in various tissues and their Ka/Ks ratio indicated a negative selection pressure. In vivo analysis in Δ3MSR yeast strain indicated that the GmMSRA6 did not have activity toward MetO, contrasting to GmMSRA3 which had catalytic Cys and had activity. When exposed to H2O2-induced oxidative stress, GmMSRA6 did not confer any protection to the Δ3MSR yeast strain. Overexpression of GmMSRA6 in Arabidopsis thaliana did not alter the plant's phenotype under physiological conditions. However, the transgenic plants exhibited slightly higher sensitivity toward salinity-induced stress. Taken together, this data suggested that the plant MSRAs withoutthe catalytic Cys are not enzymatically active and their existence may be explained by a role in regulating plant MSR activity via dominant-negative substrate competition mechanism.

Expression of nirK and nirS genes in two strains of Pseudomonas stutzeri harbouring both types of NO-forming nitrite reductases

Reduction of nitrite to nitric oxide in denitrification is catalysed by two different nitrite reductases, encoded by nirS or nirK. Long considered mutually exclusive and functionally redundant in denitrifying bacteria, we show expression of both genes co-occurring in Pseudomonas stutzeri. The differential expression patterns between strain AN10 and JM300 in relation to oxygen and nitrate and their different denitrification phenotypes, with AN10 reducing nitrate more rapidly and accumulating nitrite, suggest that nirS and nirK can have different roles. Dissimilar gene arrangements and transcription factors in the nir gene neighbourhoods could explain the observed differences in gene expression and denitrification activity.

Nitrite Reduction in Aqueous Solution Mediated by Amavadin Homologues: N2 O Formation and Water Oxidation.

Reactions of two vanadium(IV) complex anions that are homologues of amavadin, [V(HIDPA)2 ]2- and [V(HIDA)2 ]2- (HIDPA=N-oxyiminodipropionate, HIDA=N-oxyiminodiacetate), with the nitrite ion (NO2- ) in aqueous solution were investigated by experimental (absorption spectroscopy in the visible range, through measurements of dioxygen formed in solution from water oxidation and identification of nitrogen oxide species of a gaseous atmosphere from nitrite reduction by using an IR analyser) and theoretical methods. Two reactions, mediated by the vanadium complexes, with environmental and biological significance, were observed in this system, namely, reduction of nitrite to N2 O and oxidation of water to molecular oxygen. The reduction of nitrite, as studied by DFT calculations, occurs through the formation of NO (ΔG≠ =14.3 kcal mol-1 ), which is strongly dependent on pH and slightly endergonic, and is then easily converted into N2 O, with an overall activation barrier of ΔG≠ =11.8 kcal mol-1 . The later process includes dimerisation of NO assisted by one molecule of the V complex, protonation and oxidation of the formed ONNO.- ligand by another amavadin molecule or by nitrite, and NO bond cleavage/proton transfer in the ONNOH- ligand. The results indicate that amavadin exhibits an unusual nitrite reductase type activity that could be involved in nitrogen metabolism of Amanita muscaria and other fungi containing this vanadium complex.

Presence of Cu-Type (NirK) and cd1-Type (NirS) Nitrite Reductase Genes in the Denitrifying Bacterium Bradyrhizobium nitroreducens sp. nov.

Nitrite reductase is a key enzyme for denitrification. There are two types of nitrite reductases: copper-containing NirK and cytochrome cd1-containing NirS. Most denitrifiers possess either nirK or nirS, although a few strains been reported to possess both genes. We herein report the presence of nirK and nirS in the soil-denitrifying bacterium Bradyrhizobium sp. strain TSA1T. Both nirK and nirS were identified and actively transcribed under denitrification conditions. Based on physiological, chemotaxonomic, and genomic properties, strain TSA1T (=JCM 18858T=KCTC 62391T) represents a novel species within the genus Bradyrhizobium, for which we propose the name Bradyrhizobium nitroreducens sp. nov.

Quantitative analyses of denitrifying bacterial diversity from a seasonally hypoxic monsoon governed tropical coastal region

Microbial community mediated denitrification leads to nitrate reduction and, its eventual removal from marine ecosystems. Therefore, it is necessary to understand the functional diversity in terms of the abundance and types of nitrate reductases in the microbial communities extant in the hypoxic/suboxic waters where organic matter oxidation is predominantly nitrate- reduction mediated. For this study, water samples from the surface, mid-depth and close to bottom were collected from three coastal locations along the west coast of India during Summer monsoon (SuM), Fall intermonsoon (FIM) and, Spring intermonsoon (SIM). The abundance of nitrate (narG), nitrite (nirS) and nitrous oxide (nosZ) reductase genes from these water samples were quantified by qPCR method. Besides the distinct spatio-temporal differences, the overall ranges of these three functional genes across the sampling sites ranged from 1.9 x 107 to 7.9 x 107 copies L-1 (narG), from 0.001 x 106 to 0.30 x 106 copies L-1 (nirS) and from 0.30 x 106 to 2.9 x 106 copies L-1 (nosZ). Functional gene sequencing of bacterial communities possessing these reductases were diverse and, dominated by members of Alpha-, Beta- and Gamma-proteobacteria, including taxonomic groups containing well known denitrifiers such as Pseudogulbenkiania, Kocuria, Pseudomonas, Herbaspirillum, Achromobacter, Rhodoferax, Mesorhizobium, Sinorhizobium, Shinella, Bradyrhizobiaceae, Rhodopseudomonas, Dinoroseobacter, Paracoccus, Rhodobacter, Ruegeria and Azospirillum sp. Assemblages of bacteria possessing narG, nirS, and nosZ indicated that complete denitrification could occur, particularly in the samples collected close to the bottom.

In vivo evaluation of hot water extract of Acorus gramineus root against benign prostatic hyperplasia

BackgroundAcorus gramineus has been reported to exhibit various pharmacological effects including inhibition of cholesterol synthesis, enhancement of lipid metabolism, prevention of dementia and inhibition of mast cell growth. According to the Chinese compendium of materia media, it has been reported that Acorus spp. is effective for sedation, dementia prevention as well as diuretic effect. In addition, it showed more than equivalent activity compared to furosoemide, a drug known to be effective in diuretic action in animal model study. However, their effectiveness against benign prostatic hyperplasia (BPH) of Acorus gramineus has not been reported. This study was designed to evaluate the effect of Acorus gramineus root hot water extract (AG) against BPH in vivo.MethodsMale rats, 10 weeks of age and weighing 405 g ± 10 g, were used for this study. Biomarkers were evaluated including prostate weight, prostate weight ratio, hormonal changes, 5-α reductase type II androgen receptor (AR) of the prostate gland and anti-oxidant activation factors related to BPH. These biomarkers were measured in vivo test.ResultsAG showed significant effect at the 250 and 500 mg/kg/day in rats. Groups treated with AG displayed significantly lower levels of prostate gland weight (0.79 g) compared to the BPH induced group (1.19 g). Also, dihydrotestosterone (DHT) level was decreased from 61.8 to 100% and androgen receptor expression level was decreased from 111 to 658%. Any hematological toxicity of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) level wasn’t observed.ConclusionThis study indicated that AG was effective for reducing BPH symptoms.Trial registrationNot applicable.

Disguised as a Sulfate Reducer: Growth of the Deltaproteobacterium Desulfurivibrio alkaliphilus by Sulfide Oxidation with Nitrate.

ABSTRACTThis study demonstrates that the deltaproteobacterium Desulfurivibrio alkaliphilus can grow chemolithotrophically by coupling sulfide oxidation to the dissimilatory reduction of nitrate and nitrite to ammonium. Key genes of known sulfide oxidation pathways are absent from the genome of D. alkaliphilus. Instead, the genome contains all of the genes necessary for sulfate reduction, including a gene for a reductive-type dissimilatory bisulfite reductase (DSR). Despite this, growth by sulfate reduction was not observed. Transcriptomic analysis revealed a very high expression level of sulfate-reduction genes during growth by sulfide oxidation, while inhibition experiments with molybdate pointed to elemental sulfur/polysulfides as intermediates. Consequently, we propose that D. alkaliphilus initially oxidizes sulfide to elemental sulfur, which is then either disproportionated, or oxidized by a reversal of the sulfate reduction pathway. This is the first study providing evidence that a reductive-type DSR is involved in a sulfide oxidation pathway. Transcriptome sequencing further suggests that nitrate reduction to ammonium is performed by a novel type of periplasmic nitrate reductase and an unusual membrane-anchored nitrite reductase.

Emerging issues in disorders/differences of sex development (DSD).

Disorders/Differences of Sex Development (DSD), as defined by the 2006 Consensus Statement, are "congenital conditions in which development of chromosomal, gonadal, or anatomic sex is atypical." They represent a spectrum of chronic medical conditions collectively affecting about 1% of the population and are associated with increased risk of infertility, cancer, and psychosocial distress. Clinical management in DSD is subject to multiple controversies about gender assignment, the timing and appropriateness of genital surgery and the approach to disclosure. There is dissent within and between stakeholders (healthcare providers, advocacy groups, families) regarding what constitutes optimal care. This special issue investigates the progress made as well as the uncertainties remaining a decade after the consensus statement and the gaps to be filled by future research and improved clinical practice. It discusses the increasing intricacy of genetic variant interpretation in the era of next-generation sequencing and the associated complexity of phenotypic variability. The issue tackles ethical dilemmas and the complicated decision-making process of assignment of sex of rearing at birth in cases of 5-alpha reductase type 2 deficiency, surveys delivery of clinical services in the United States, discusses challenges of interdisciplinary care and of educating patients and parents about DSD,and reviews the factors predisposing to gonadal tumor and their consequences on clinical management.

Unexpected ethical dilemmas in sex assignment in 46,XY DSD due to 5-alpha reductase type 2 deficiency.

Sex assignment at birth remains one of the most clinically challenging and controversial topics in 46,XY disorders of sexual development (DSD). This is particularly challenging in deficiency of 5-alpha reductase type 2 given that external genitalia are typically undervirilized at birth but typically virilize at puberty to a variable degree. Historically, most individuals with 5-alpha reductase deficiency were raised females. However, reports that over half of patients who underwent a virilizing puberty adopted an adult male gender identity have challenged this practice. Consensus guidelines on assignment of sex of rearing at birth are equivocal or favor male assignment in the most virilized cases. While a male sex of rearing assignment may avoid lifelong hormonal therapy and/or allow the potential for fertility, female sex assignment may be more consistent with external anatomy in the most severely undervirilized cases. Herein, we describe five patients with 46,XY DSD due 5-alpha-reductase type 2 deficiency, all with a severe phenotype. An inter-disciplinary DSD medical team at one of two academic centers evaluated each patient. This case series illustrates the complicated decision-making process of assignment of sex of rearing at birth in 5-alpha reductase type 2 deficiency and the challenges that arise when the interests of the child, parental wishes, recommendations of the medical team, and state law collide.

Synthesis of enantiomerically enriched drug precursors and an insect pheromone via reduction of ketones using commercially available carbonyl reductase screening kit “Chiralscreen® OH”

Commercially available “Chiralscreen® OH” starter kit containing five types of carbonyl reductases (E001, E007, E031, E039, and E078) was used for the reduction of several aromatic and aliphatic ketones to obtain enantiomerically enriched drug precursors and an insect pheromone. Almost stereochemically pure secondary alcohols, used in the synthesis of drugs such as (R)-rasagiline mesylate, (S)-rivastigmine, (R)-chlorphenesin carbamate, and (R)-mexiletine, and the insect pheromone (4S,5R)-sitophilure, were conveniently obtained. The enzymes worked well with ketones containing at least one non-bulky substituent at the carbonyl group. The diverse stereochemical preference of the above five carbonyl reductases was clarified.

Homozygous Ala65Pro Mutation with V89L Polymorphism in SRD5A2 Deficiency.

Objective:Deficiency of steroid 5-alpha reductase type 2 (5αRD2) is a rare autosomal recessive disorder caused by mutations in the SRD5A2 gene. A defect in the 5-alpha reductase enzyme, which ensures conversion of testosterone into dihydrotestosterone, leads to disorders of sex development. This study presents the clinical and genetic results of patients with 5αRD2 deficiency.Methods:5αRD2 deficiency was detected in 6 different patients from 3 unrelated families. All patients were reared as girls. Two of the patients presented with primary amenorrhea, one with primary amenorrhea and rejection of female gender, and the others with masses in their inguinal canals. Chromosome and sex-determining region Y (SRY) gene analyses were performed in all patients. Additionally, five exons of the SRD5A2 gene were amplified with polymerase chain reaction in the obtained DNA samples and evaluated.Results:While 46,XY was identified in 5 patients, 47,XXY was detected in one patient. The SRY gene was positive in all patients. The p.Ala65Pro (c193G>C) mutation and V89L polymorphism were observed in exon 1 of the SRD5A2 gene in all patients.Conclusion:Identification of this mutation and polymorphism is a significant indicator of presence of 5αRD2 deficiency in Southeastern Turkey, a geographical region where consanguineous marriages are also highly common.

Spatial Abundance and Distribution of Potential Microbes and Functional Genes Associated with Anaerobic Mineralization of Pentachlorophenol in a Cylindrical Reactor.

Functional interplays of microbial activity, genetic diversity and contaminant transformation are poorly understood in reactors for mineralizing halogenated aromatics anaerobically. Here, we investigated abundance and distribution of potential microbes and functional genes associated with pentachlorophenol (PCP) anaerobic mineralization in a continuous-flow cylindrical reactor (15 cm in length). PCP dechlorination and the metabolite (phenol) were observed at segments 0–8 cm from inlet, where key microbes, including potential reductive dechlorinators (Dehalobacter, Sulfurospirillum, Desulfitobacterium and Desulfovibrio spp.) and phenol degraders (Cryptanaerobacter and Syntrophus spp.), as well as putative functional genes, including putative chlorophenol reductive dehalogenase (cprA) and benzoyl-CoA reductase (bamB), were highly enriched simultaneously. Five types of putative cprAs, three types of putative bamBs and seven types of putative nitrogenase reductase (nifHs) were determined, with their copy numbers decreased gradually from inlet to outlet. Distribution of chemicals, bacteria and putative genes confirmed PCP dechlorination and phenol degradation accomplished in segments 0–5 cm and 0–8 cm, respectively, contributing to a high PCP mineralization rate of 3.86 μM d−1. Through long-term incubation, dechlorination, phenol degradation and nitrogen fixation bacteria coexisted and functioned simultaneously near inlet (0–8 cm), verified the feasibility of anaerobic mineralization of halogenated aromatics in the compact reactor containing multiple functional microbes.

Regulation of steroid-5-alpha-reductase 2 (SRD5A2) in human prostate by epigenetic modifications.

204 Background: 5-alpha reductase type 2 (SRD5A2), an enzyme that is critical for prostatic development and growth. We have found that many aging prostate tissues do not express the enzyme. We previously showed that expression of SRD5A2 is not static and epigenetic modulations by DNA methyltransferase and pro-inflammatory cytokines play important roles in silencing of SRD5A2. Here we wished to define the methylation pattern and identify specific CpG dinucleotides that are methylated in the SRD5A2promoter region. Methods: Ninety six prostate samples from patients were obtained by transurethral resection of prostate (TURP). Methylation of SRD5A2 promoter was assessed using Methylated CpG Island Recovery Assay (MIRA). Bisulfide conversion of Genomic DNA was performed using Epimark bisulfide conversion kit. Primers for bisulfide sequencing were designed using MethPrimer software and bisulfide sequencing was performed using 3730XL DNA Sequencers. Binding of histone demethylase to promoter DNA was analyzed by ChiP assay. Results: We randomly selected 3 TURP samples with methylated SRD5A2 promoters and 3 TURP samples with un-methylated SRD5A2 promoters, and then bisulfide conversion and sequencing were performed to verify the methylation pattern of CpG dinucleotides on SRD5A2 promoter. We found that bisulfide sequencing analysis of SRD5A2 promoter was consistent with MIRA analysis. To further analyze the mediators of SRD5A2 promoter region, we show that TNF-alpha up-regulates expression of Snail protein, which is a central regulator of both DNA methylation and histone methylation, and increases the binding of H3K9me to SRD5A2promoter region, but not H3K27me or H4K20me. Conclusions: Methylation of SRD5A2 promoter, which is regulated by DNMT1, proinflammatory cytokines and the histone methylase, H3K9me, accounts for suppression of SRD5A2 in many adult human prostate tissues. Bisulfide conversion and sequencing confirm and focus the specified CpG dinucleotides that are methylated enabling us to evaluate mechanisms and patterns of SRD5A2 promoter methylation in order to study the functional significance of SRD5A2 methylation. Grant support: NIH/R01 DK091353.

Epigenetic silencing and variable expression of SRD5A2 in specific compartments of human prostate.

38 Background: The steroid-5α reductase type 2 gene (SRD5A2) and protein play a significant role in the development and growth of prostate tissue. SRD5A2 can be expressed in both the epithelial and stromal compartments of the prostate gland. Previously, we have shown that somatic suppression of SRD5A2 during adulthood is dependent on epigenetic changes associated with methylation of the promoter region of the SRD5A2 gene. Here we determined whether variability of SRD5A2 expression occurs in specific compartments of prostate tissues. Methods: Frozen and formalin-fixed sections of human adult prostate tissue was used. Laser capture microdissection (LCM) was performed to obtain a pure population of epithelial and stromal cells. Approximately 500–600 excised cells were captured, and the methylation pattern of SRD5A2 was determined by DNA methylation pull-down assay kit. The expression of SRD5A2 protein was identified with immunohistochemistry and quantitated by ELISA. Results: In the whole prostate tissue, samples with high SRD5A2 immunoreactivity had much lower levels of SRD5A2 promoter methylation compared to those with low SRD5A2 immunoreactivity. DNA methylation assay for the epithelial compartment closely resembled the findings of the whole prostate tissue. In contrast, the samples from the stromal compartment showed uniform methylation irrespective of the methylation pattern in the epithelial compartment or the whole tissue. The expression of SRD5A2 protein quantitated by ELISA further showed that the variable expression of SRD5A2 is better determined by epithelial compartment expression. Conclusions: Our data suggests that variability of SRD5A2 expression is dependent on the methylation pattern and expression of SRD5A2 in the epithelial compartment and not the stroma. Therefore, if epithelial expression of SRD5A2 is more representative of the whole prostatic tissue expression, then it is logical that SRD5A2 inhibitor’s efficacy is dependent on involution of the epithelial cells. Our findings will have broad implications for the use of 5ARIs in the treatment of BPH and for the chemoprevention of prostate cancer. Grant support: NIH/R01 DK091353

Evidence for the involvement of two heterodisulfide reductases in the energy-conserving system of Methanomassiliicoccus luminyensis.

Methanomassiliicoccus luminyensis was isolated from the human gut, and requires H2 and methanol or methylamines to produce methane. The organism lacks cytochromes, indicating that it cannot couple membrane-bound electron transfer reactions with extrusion of H(+) or Na(+) ions using known methanogenic pathways. Furthermore, M. luminyensis contains a soluble hydrogenase/heterodisulfide reductase complex (MvhAGD/HdrABC) as found in obligate hydrogenotrophic methanogens, but the energy-conserving methyltransferase (MtrA-H) is absent. Thus, the question arises as to how this species synthesizes ATP. We present evidence that M. luminyensis uses two types of heterodisulfide reductases (HdrABC and HdrD) in a novel process for energy conservation. Quantitative RT-PCR studies revealed that genes encoding these heterodisulfide reductases showed high expression levels. Other genes with high transcript abundance were fpoA (part of the operon encoding the 'headless' F420 H2 dehydrogenase) and atpB (part of the operon encoding the A1 Ao ATP synthase). High activities of the soluble heterodisulfide reductase HdrABC and the hydrogenase MvhADG were found in the cytoplasm of M. luminyensis. Also, heterologously produced HdrD was able to reduce CoM-S-S-CoB using reduced methylviologen as an electron donor. We propose that membrane-bound electron transfer is based on conversion of two molecules of methanol and concurrent formation of two molecules of the heterodisulfide CoM-S-S-CoB. First the HdrABC/MvhADG complex catalyzes the H2 -dependent reduction of CoM-S-S-CoB and formation of reduced ferredoxin. In a second cycle, reduced ferredoxin is oxidized by the 'headless' F420 H2 dehydrogenase, thereby translocating up to 4 H(+) across the membrane, and electrons are channeled to HdrD for reduction of the second heterodisulfide.

POLYPRENOL REDUCTASE2 Deficiency Is Lethal in Arabidopsis Due to Male Sterility.

Dolichol is a required cofactor for protein glycosylation, the most common posttranslational modification modulating the stability and biological activity of proteins in all eukaryotic cells. We have identified and characterized two genes, PPRD1 and -2, which are orthologous to human SRD5A3 (steroid 5α reductase type 3) and encode polyprenol reductases responsible for conversion of polyprenol to dolichol in Arabidopsis thaliana. PPRD1 and -2 play dedicated roles in plant metabolism. PPRD2 is essential for plant viability; its deficiency results in aberrant development of the male gametophyte and sporophyte. Impaired protein glycosylation seems to be the major factor underlying these defects although disturbances in other cellular dolichol-dependent processes could also contribute. Shortage of dolichol in PPRD2-deficient cells is partially rescued by PPRD1 overexpression or by supplementation with dolichol. The latter has been discussed as a method to compensate for deficiency in protein glycosylation. Supplementation of the human diet with dolichol-enriched plant tissues could allow new therapeutic interventions in glycosylation disorders. This identification of PPRD1 and -2 elucidates the factors mediating the key step of the dolichol cycle in plant cells which makes manipulation of dolichol content in plant tissues feasible.

Dual utilization of NADPH and NADH cofactors enhances xylitol production in engineered Saccharomyces cerevisiae.

Xylitol, a natural sweetener, can be produced by hydrogenation of xylose in hemicelluloses. In microbial processes, utilization of only NADPH cofactor limited commercialization of xylitol biosynthesis. To overcome this drawback, Saccharomyces cerevisiae D452-2 was engineered to express two types of xylose reductase (XR) with either NADPH-dependence or NADH-preference. Engineered S. cerevisiae DWM expressing both the XRs exhibited higher xylitol productivity than the yeast strain expressing NADPH-dependent XR only (DWW) in both batch and glucose-limited fed-batch cultures. Furthermore, the coexpression of S. cerevisiae ZWF1 and ACS1 genes in the DWM strain increased intracellular concentrations of NADPH and NADH and improved maximum xylitol productivity by 17%, relative to that for the DWM strain. Finally, the optimized fed-batch fermentation of S. cerevisiae DWM-ZWF1-ACS1 resulted in 196.2 g/L xylitol concentration, 4.27 g/L h productivity and almost the theoretical yield. Expression of the two types of XR utilizing both NADPH and NADH is a promising strategy to meet the industrial demands for microbial xylitol production.

Androgen levels and apoptosis in the testis during postnatal development of finasteride-treated male rat offspring.

The hormone-dependent events that occur throughout the first wave of spermatogenesis, such as the establishment of the number of Sertoli cells (SCs) and spermatogonial stem cells (SSCs) within the seminiferous cords and the setting up of the blood-testis barrier, are important for adult male fertility. Any changes in the T/DHT ratio can result in male subfertility or even infertility. In this study we aimed to evaluate effects of paternal exposure to 5-alpha reductase type 2 inhibitor, finasteride on litter size, androgen levels and germ cell apoptosis in male offspring during postnatal development. The subjects of the study were 7, 14, 21/22, 28, and 90-day-old Wistar male rats (F1:Fin) born from females fertilized by finasteride-treated rats. Offspring born from untreated parental animals were used as a control group (F1:Control). Animals and the collected testes were weighed, blood and intratesticular levels of T and DHT were measured by ELISA, and the apoptotic index of testicular cells was evaluated by TUNEL technique. We observed difficulties in obtaining male newborns from female rats fertilized by finasteride-treated male rats. In the F1:Fin rats, changes in the body and testes weights occurred, and a lower number of apoptotic cells was found during postnatal maturation of the seminiferous epithelium. Changes in androgen concentrations during the first spermatogenesis wave and adult life were also evident. Finasteride treatment of male adult rats may not only cause a decrease in the fertility of parental rats, but also could lead to incorrect, androgen-sensitive course of spermatogenesis in their offspring.

Flavodoxin-Like Proteins Protect Candida albicans from Oxidative Stress and Promote Virulence.

The fungal pathogen Candida albicans causes lethal systemic infections in humans. To better define how pathogens resist oxidative attack by the immune system, we examined a family of four Flavodoxin-Like Proteins (FLPs) in C. albicans. In agreement with previous studies showing that FLPs in bacteria and plants act as NAD(P)H quinone oxidoreductases, a C. albicans quadruple mutant lacking all four FLPs (pst1Δ, pst2Δ, pst3Δ, ycp4Δ) was more sensitive to benzoquinone. Interestingly, the quadruple mutant was also more sensitive to a variety of oxidants. Quinone reductase activity confers important antioxidant effects because resistance to oxidation was restored in the quadruple mutant by expressing either Escherichia coli wrbA or mammalian NQO1, two distinct types of quinone reductases. FLPs were detected at the plasma membrane in C. albicans, and the quadruple mutant was more sensitive to linolenic acid, a polyunsaturated fatty acid that can auto-oxidize and promote lipid peroxidation. These observations suggested that FLPs reduce ubiquinone (coenzyme Q), enabling it to serve as an antioxidant in the membrane. In support of this, a C. albicans coq3Δ mutant that fails to synthesize ubiquinone was also highly sensitive to oxidative stress. FLPs are critical for survival in the host, as the quadruple mutant was avirulent in a mouse model of systemic candidiasis under conditions where infection with wild type C. albicans was lethal. The quadruple mutant cells initially grew well in kidneys, the major site of C. albicans growth in mice, but then declined after the influx of neutrophils and by day 4 post-infection 33% of the mice cleared the infection. Thus, FLPs and ubiquinone are important new antioxidant mechanisms that are critical for fungal virulence. The potential of FLPs as novel targets for antifungal therapy is further underscored by their absence in mammalian cells.

Abstract 1052: Variable expression of 5-alpha reductase 2 in the aging adult prostate is regulated by DNA methylation

Abstract BACKGROUND: 5-alpha reductase type 2 (SRD5A2), an enzyme that is critical for prostatic development and growth, is utilized as an inhibitory target by finasteride for patients with bladder outlet obstrution secondary to BPH. However, we have found that many aging benign prostate tissues do not express the enzyme. Since the SRD5A2 promoter contains a CpG island, we hypothesized that somatic methylation of the promoter would be regulated by DNA methyltransferases leading to suppression of SRD5A2. METHODS: Benign prostatic tissues from wild-type mice at 3, 6 and 12 months of age were used. In addition, 96 prostate samples from human male patients who were treated by TURP for bladder outlet obstruction secondary to BPH were used. Methylation of SRD5A2 promoter was assessed using Methylated CpG Island Recovery Assay (MIRA). DNMT1 siRNA and 5-AZA-C were used to determine the methylation status of SRD5A2 in benign prostatic cell line, BPH-1. To determine the effect of CpG methylation, SRD5A2 promoter-luciferase constructs were methylated in vitro using M.SssI methylase. Statistical analyses were performed with JMP Pro version 11 (SAS Institute Inc., Cary, NC). RESULTS: We analyzed 96 human BPH samples from transurethral resection of prostate (TURP) surgeries and found that absence of SRD5A2 was closely associated with hypermethylation of the SRD5A2 promoter region. We found that methylation of SRD5A2 was regulated by DNA methytransferase 1 (DNMT1) and the cytokines, TNF-alpha, NF-κB and IL-6, regulated DNMT1protein expression and thereby indirectly affected SRD5A2 promoter methylation and gene expression. Suppression of cytokines inhibited activity of DNMT1, while over-expression of p65 or treatment with TNF-alpha or IL-6 up-regulated DNMT1. In addition, we found that methylation of the SRD5A2 promoter and concomitant decrease in protein expression were closely associated with patient's increasing age (P<0.05). Finally, in murine prostate tissues, cytokine levels, DNMT1 and global methylation were all increased in older mice. Induction of inflammation with lipopolysaccharide (LPS) stimulated the TNFR1/NF-κB/IL-6/DNMT1 pathway, leading to hypermethylation of the SRD5A2 promoter and silencing of SRD5A2, while treatment with both LPS and TNF-alpha inhibitor reversed this pathway and reactivated SRD5A2. CONCLUSIONS: Expression of SRD5A2 is not static and ubiquitous in benign adult prostate tissues. We show that SRD5A2 expression is lacking in many benign human adult prostate tissues. Methylation of SRD5A2 promoter region, which is regulated by DNMT1, accounts for absence of SRD5A2 expression in many adult human prostate tissues. Methylation and expression of SRD5A2 may be used as a gene signature to tailor therapies for more effective treatment of prostatic diseases. Citation Format: Ge Rongbin, Zongwei Wang, Seth Bechis, Alexander Otsetov, Shengyu Hua, Shulin Wu, Chin-Lee Wu, Shahin Tabatabaei, Aria Olumi. Variable expression of 5-alpha reductase 2 in the aging adult prostate is regulated by DNA methylation. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1052. doi:10.1158/1538-7445.AM2015-1052