Cyclic GMP Phosphodiesterase Research Articles

Rethinking of phosphodiesterase 5 inhibition: the old, the new and the perspective in human health.

The phosphodiesterases type 5 (PDE5) are catalytic enzymes converting the second messenger cyclic guanosine monophosphate (cGMP) to 5' GMP. While intracellular cGMP reduction is associated with several detrimental effects, cGMP stabilization associates with numerous benefits. The PDE5 specific inhibitors, PDE5i, found their explosive fortune as first-line treatment for erectile dysfunction (ED), due to their powerful vasoactive properties. The favorable effect for ED emerged as side-effect when PDE5i were originally proposed for coronary artery disease (CAD). From that point on, the use of PDE5i captured the attention of researchers, clinicians, and companies. Indeed, PDE5-induced intracellular cGMP stabilization offers a range of therapeutic opportunities associated not only with vasoactive effects, but also with immune regulatory/anti-inflammatory actions. Chronic inflammation is acknowledged as the common link underlying most non-communicable diseases, including metabolic and cardiac diseases, autoimmune and neurodegenerative disorders, cancer. In this scenario, the clinical exploitation of PDE5i is undeniably beyond ED, representing a potential therapeutic tool in several human diseases. This review aims to overview the biological actions exerted by PDE5i, focusing on their ability as modulators of inflammation-related human diseases, with particular attention to inflammatory-related disorders, like cardiac diseases and cancer.

Phosphodiesterase-5 Expression in Buccal Mucosa of Patients with Erectile Dysfunction One Year after Radical Prostatectomy.

(1) Background: Radical prostatectomy has a high incidence of erectile dysfunction (ED). The aim was to determine if the expression of the nitric oxide synthase-3/soluble guanylate cyclase/phosphodiesterase 5 axis could be detected in buccal mucosa and if it could be differently expressed in patients with and without ED; (2) Methods: Erectile function from 38 subjects subjected to prostatectomy was evaluated using the International Index of Erectile Function-Erectile Function Domain before and one year after surgery. Nitric oxide synthase (NOS3), β1-subunit of soluble guanylate cyclase (sGC), phosphodiesterase-5 (PDE-5) expressions, and interleukin-6 and interleukin-10 content were measured in the buccal mucosa. PDE5A rs3806808 gene polymorphism was genotyped; (3) Results: One year after prostatectomy, 15 patients had recovered functional erection, and 23 showed ED. NOS3, β1-sGC, interleukin-6, and interleukin-10 expressions were not different between patients with and without ED after radical prostatectomy. Buccal mucosa levels of PDE-5 were higher in patients with ED compared to those who recovered erectile functionality. There were no differences found in the genotype of PDE5A polymorphism; (4) Conclusions: One year after prostatectomy, patients with ED had higher PDE5 levels in their buccal mucosa than patients who had recovered erectile function. Rs3806808 PDE5A gene polymorphism was not associated with increased PDE5 expression in buccal mucosa.

Whole Exome Sequencing Revealed Paternal Inheritance of Obesity-related Genetic Variants in a Family with an Exclusively Breastfed Infant.

Obesity is a serious health problem, that progressively affects individuals' lives with comorbidities involving heart disease, stroke, and diabetes mellitus. Since its prevalence increases particularly in children under age-of-five years, its genetic and environmental causes should be determined for prevention and control of the disease. This study aimed to detect underlying genetic risk factors in a family with an exclusively breastfed obese infant. A three-generation family was recruited to be evaluated for obesity. Detailed examinations along with body mass indexcalculations were performed on available family members. Whole exome sequencing was performed on 7-month-oldobese infant utilizing Illumina-NextSeq550. Bioinformatic analyses were performed on the Genomize SEQ platform with variant filtering at minor allele frequencies (MAF)<1% for all normal populations. Sanger sequencing was applied in variant confirmation and family segregation. Neuro-motor developmental features were normal and genetic syndromes were excluded from the index. Early-onset severe obesity (4.25SDS weight-for-height) was obvious in index case, where his father and grandmother were also obese (BMIs: 38.1kg/m2 and 31.3kg/m2, respectively). WES analysis revealed deleterious variants in SH2B1, PDE11A, ADCY3, and CAPN10 genes previously associated with obesity. All variants were evaluated as novel candidates for obesity except PDE11A and family segregation confirmed paternal inheritance. This study confirmed the paternal inheritance of all potentially deleterious obesity-related variants. The cumulative effect of individual variants might explain the obesity phenotype in this family. The infant is recommended to be under periodic follow-up due to increased risk for later childhood obesity.

Germline NGS targeted analysis in adult patients with sporadic adrenocortical carcinoma

BackgroundAdrenocortical carcinoma (ACC) is a rare cancer that arises sporadically or due to hereditary syndromes. Data on germline variants (GVs) in sporadic ACC are limited. Our aim was to characterize GVs of genes potentially related to adrenal diseases in 150 adult patients with sporadic ACC. MethodsThis was a retrospective analysis of stage I-IV ACC patients with sporadic ACC from two reference centers for ACC in Italy. Patients were included in the analysis if they had confirmed diagnosis of ACC, a frozen peripheral blood sample and complete clinical and follow-up data. Next generation sequencing technology was used to analyze the prevalence of GVs in a custom panel of 17 genes belonging to either cancer-predisposition genes or adrenocortical-differentiation genes categories. ResultsWe identified 18 GVs based on their frequency, enrichment and predicted functional characteristics. We found six pathogenic (P) or likely pathogenic (LP) variants in ARMC5, CTNNB1, MSH2, PDE11A and TP53 genes; and twelve variants lacking evidence of pathogenicity. New unique P/LP variants were identified in TP53 (p.G105D) and, for the first time, in ARMC5 (p.P731R). The presence of P/LP GVs was associated with reduced survival outcomes and had a significant and independent impact on both progression-free survival and overall survival. ConclusionsGVs were present in 6.7 % of patients with sporadic ACC, and we identified novel variants of ARMC5 and TP53. These findings may improve understanding of ACC pathogenesis and enable genetic counseling of patients and their families.

Screening of Litter-Size-Associated SNPs in NOX4, PDE11A and GHR Genes of Sheep.

In previous studies, NOX4, PDE11A and GHR genes have been screened as important candidate genes for litter size in sheep by using the GWAS method; however, neither their effects on litter size nor the loci associated with litter size have been identified. In this study, three candidate loci (c.1057-4C > T in NOX4, c.1983C > T in PDE11A and c.1618C > T in GHR) were first screened based on our previous resequencing data of 10 sheep breeds. After the three loci were genotyped using Sequenom MassARRAY technology, we carried out population genetics analysis on the three loci and performed association analysis between the polymorphism of the three loci and the litter size of sheep. The results of population genetics analysis suggested that c.1057-4C > T in NOX4 and c.1983C > T in PDE11A may be subject to natural or artificial selection. The results of association analysis indicated that litter size was significantly associated with c.1057-4C > T in NOX4 and c.1983C > T in PDE11A (p < 0.05) in Small Tail Han sheep, and there was no significant interaction effect between the two loci on the litter size. In summary, c.1057-4C > T in NOX4 and c.1983 C > T in PDE11A can be considered candidate molecular markers for improving litter size in sheep.

High-frequency variants in PKA signaling-related genes within a large pediatric cohort with obesity or metabolic abnormalities.

Pediatric obesity has steadily increased in recent decades. Large-scale genome-wide association studies (GWAS) conducted primarily in Eurocentric adult populations have identified approximately 100 loci that predispose to obesity and type II diabetes. GWAS in children and individuals of non-European descent, both disproportionately affected by obesity, are fewer. Rare syndromic and monogenic obesities account for only a small portion of childhood obesity, so understanding the role of other genetic variants and their combinations in heritable obesities is key to developing targeted and personalized therapies. Tight and responsive regulation of the cAMP-dependent protein kinase (PKA) signaling pathway is crucial to maintaining healthy energy metabolism, and mutations in PKA-linked genes represent the most common cause of monogenic obesity. For this study, we performed targeted exome sequencing of 53 PKA signaling-related genes to identify variants in genomic DNA from a large, ethnically diverse cohort of obese or metabolically challenged youth. We confirmed 49 high-frequency variants, including a novel variant in the PDE11A gene (c.152C>T). Several other variants were associated with metabolic characteristics within ethnic groups. We conclude that a PKA pathway-specific variant search led to the identification of several new genetic associations with obesity in an ethnically diverse population.

Identification of Neurotransmission and Synaptic Biological Processes Disrupted in Autism Spectrum Disorder Using Interaction Networks and Community Detection Analysis.

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder characterized by communication deficits and repetitive behavioral patterns. Hundreds of candidate genes have been implicated in ASD, including neurotransmission and synaptic (NS) genes; however, the genetic architecture of this disease is far from clear. In this study, we seek to clarify the biological processes affected by NS gene variants identified in individuals with ASD and the global networks that link those processes together. For a curated list of 1216 NS candidate genes, identified in multiple databases and the literature, we searched for ultra-rare (UR) loss-of-function (LoF) variants in the whole-exome sequencing dataset from the Autism Sequencing Consortium (N = 3938 cases). Filtering for population frequency was carried out using gnomAD (N = 60,146 controls). NS genes with UR LoF variants were used to construct a network of protein-protein interactions, and the network's biological communities were identified by applying the Leiden algorithm. We further explored the expression enrichment of network genes in specific brain regions. We identified 356 variants in 208 genes, with a preponderance of UR LoF variants in the PDE11A and SYTL3 genes. Expression enrichment analysis highlighted several subcortical structures, particularly the basal ganglia. The interaction network defined seven network communities, clustering synaptic and neurotransmitter pathways with several ubiquitous processes that occur in multiple organs and systems. This approach also uncovered biological pathways that are not usually associated with ASD, such as brain cytochromes P450 and brain mitochondrial metabolism. Overall, the community analysis suggests that ASD involves the disruption of synaptic and neurotransmitter pathways but also ubiquitous, but less frequently implicated, biological processes.

The rs2682826 Polymorphism of the NOS1 Gene Is Associated with the Degree of Disability of Erectile Dysfunction.

Erectile dysfunction (ED) is a common male disorder, often associated with cardiovascular disease and ageing. The Sildenafil, a PDE5 inhibitor, can improve the erectile function by prolonging the nitric oxide (NO) downstream effect. NO is a molecule of pivotal importance in erection physiology and is mainly produced by neuronal nitric oxide synthase (nNOS) and endothelial NO synthase (eNOS). While it has been shown that eNOS and nNOS genetic polymorphisms could be associated with Sildenafil responsiveness in ED, no study so far has assessed whether nNOS polymorphisms and PDE5A polymorphism could be associated with increased risk to ED or with intensity of symptoms. A total of 119 ED patients and 114 controls were studied, with evaluation of the clinical disability by the International Index for Erectile Function instrument, plasma assessment of nitrite levels and genomic DNA analysis regarding the rs41279104 and rs2682826 polymorphisms of the NOS1 gene and the rs2389866, rs3733526 and rs13124532 polymorphisms of the PDE5A gene. We have found a significant association of the rs2682826 with lower IIEF scores in the clinical ED group. While this result should be confirmed in other populations, it may be helpful in establishing a genetic panel to better assess disease risk and prognosis on ED therapy.

Sex-specific effects of daily tadalafil on diabetic heart kinetics in RECOGITO, a randomized, double-blind, placebo-controlled trial.

Cyclic GMP-phosphodiesterase type 5 (PDE5) inhibition has been shown to counteract maladaptive cardiac changes triggered by diabetes in some but not all studies. We performed a single-center, 20-week, double-blind, randomized, placebo-controlled trial (NCT01803828) to assess sex differences in cardiac remodeling after PDE5 inhibition in patients with diabetic cardiomyopathy. A total of 122 men and women (45 to 80 years) with long-duration (>3 years) and well-controlled type 2 diabetes mellitus (T2DM; HbA1c < 86 mmol/mol) were selected according to echocardiographic signs of cardiac remodeling. Patients were randomly assigned (1:1) to placebo or oral tadalafil (20 mg, once daily). The primary outcome was to evaluate sex differences in cardiac torsion change. Secondary outcomes were changes in cardiovascular, metabolic, immune, and renal function. At 20 weeks, the treatment-by-sex interaction documented an improvement in cardiac torsion (-3.40°, -5.96; -0.84, P = 0.011) and fiber shortening (-1.19%, -2.24; -0.14, P = 0.027) in men but not women. The primary outcome could not be explained by differences in cGMP concentrations or tadalafil pharmacodynamics. In both sexes, tadalafil improved hsa-miR-199-5p expression, biomarkers of cardiovascular remodeling, albuminuria, renal artery resistive index, and circulating Klotho concentrations. Immune cell profiling revealed an improvement in low-grade chronic inflammation: Classic CD14++CD16- monocytes reduced, and Tie2+ monocytes increased. Nine patients (14.5%) had minor adverse reactions after tadalafil administration. Continuous PDE5 inhibition could offer a strategy to target cardiorenal complications of T2DM, with sex- and tissue-specific responses. Further studies are needed to confirm Klotho and hsa-miR-199-5p as markers for T2DM complications.

Association of DNA Methylation in Blood Pressure-Related Genes With Ischemic Stroke Risk and Prognosis.

BackgroundA genome-wide association study identified 12 genetic loci influencing blood pressure and implicated a role of DNA methylation. However, the relationship between methylation and ischemic stroke has not yet been clarified. We conducted a large-sample sequencing study to identify blood leukocyte DNA methylations as novel biomarkers for ischemic stroke risk and prognosis based on previously identified genetic loci.MethodsMethylation levels of 17 genes were measured by sequencing in 271 ischemic stroke cases and 323 controls, and the significant associations were validated in another independent sample of 852 cases and 925 controls. The associations between methylation levels and ischemic stroke risk and prognosis were evaluated.ResultsMethylation of AMH, C17orf82, HDAC9, IGFBP3, LRRC10B, PDE3A, PRDM6, SYT7 and TBX2 was significantly associated with ischemic stroke. Compared to participants without any hypomethylated targets, the odds ratio (OR) (95% confidence interval, CI) for those with 9 hypomethylated genes was 1.41 (1.33–1.51) for ischemic stroke. Adding methylation levels of the 9 genes to the basic model of traditional risk factors significantly improved the risk stratification for ischemic stroke. Associations between AMH, HDAC9, IGFBP3, PDE3A and PRDM6 gene methylation and modified Rankin Scale scores were significant after adjustment for covariates. Lower methylation levels of AMH, C17orf82, PRDM6 and TBX2 were significantly associated with increased 3-month mortality. Compared to patients without any hypomethylated targets, the OR (95% CI) for those with 4 hypomethylated targets was 1.12 (1.08–1.15) for 3-month mortality (P = 2.28 × 10−10).ConclusionThe present study identified blood leukocyte DNA methylations as potential factors affecting ischemic stroke risk and prognosis among Han Chinese individuals.

Utilizing Bioinformatics Technology to Explore the Potential Mechanism of Danggui Buxue Decoction against NSCLC.

While lung cancer poses a serious threat to human health, non-small-cell lung cancer (NSCLC) is the most common type of lung cancer. Danggui Buxue Decoction (DBD) is a classical traditional antitumor medicine commonly used in China. However, the potential mechanism of DBD against NSCLC has not yet been expounded. Therefore, this study clarified the potential molecular mechanism and key targets of DBD in NSCLC treatment through several technological advances, such as network pharmacology, molecular docking, and bioinformatics. Firstly, the relative active ingredients and key DBD targets were analyzed, and subsequently, a drug-ingredient-target-disease network diagram was constructed for NSCLC treatment with DBD, resulting in the identification of five main active ingredients and ten core targets according to the enrichment degree. The enrichment analysis revealed that DBD can achieve the purpose of treating NSCLC through the AGE-RAGE signaling pathway in diabetic complications. Secondly, the molecular docking approach predicted that quercetin and hederagenin have the best working mechanisms with PDE3A and PTGS1, while the survival analysis results depicted that high PDE3A gene expression has a relatively poor prognosis for NSCLC patients (p < 0.05). Additionally, PDE3A is mainly distributed in the LU65 cell line that originated from Asian population. In summary, our study results showed that DBD can treat NSCLC through the synergistic correlation between multiple ingredients, multiple targets, and multiple pathways, thus effectively improving NSCLC prognosis. This study not only reflected the medicinal value of DBD but also provided a solid structural basis for future new drug developments and targeted therapies.

Influence of tobacco cigarette heavy smoking on DNA methylation patterns and transcription levels of MAPK8IP3, GAA, ANXA2, PRRC2A, and PDE11A genes in human spermatozoa

BackgroundTobacco smoking is considered as one of the lifestyles factors that influence the sperm DNA methylation and global sperm DNA methylation and that may affect the sperm phenotype. This study was performed to investigate whether tobacco cigarette heavy smoking influences sperm DNA methylation patterns and semen parameters and to determine whether there is an alteration in the transcription level of MAPK8IP3, GAA, ANXA2, PRRC2A, and PDE11A genes in heavy smokers compared to non-smokers. Thirty samples were subjected to 450K arrays as a screening study to assess the variation in sperm DNA methylation levels between heavy smokers and non-smokers. Five CpG sites have the highest difference in methylation levels (cg07869343, cg05813498, cg09785377, cg06833981, and cg02745784), which are located in the MAPK8IP3, GAA, ANXA2, PRRC2A, and PDE11A genes, respectively, and were selected for further analysis using deep bisulfite sequencing in 280 independent samples (120 proven non-smokers and 160 heavy smokers) with a mean age of 33.8 ± 8.4 years. The global sperm DNA methylation, sperm DNA fragmentation, and chromatin non-condensation were evaluated also.ResultsA significant increase was found in the methylation level at seven, three, and seventeen CpGs within the GAA, ANXA2, and MAPK8IP3 genes amplicon, respectively (P< 0.01) in heavy smokers compared to non-smokers. Additionally, a significant increase was found in the methylation levels at all CpGs within PRRC2A and PDE11A gene amplicon (P< 0.01). A significant increase was found in the level of sperm chromatin non-condensation, DNA fragmentation, and global DNA methylation (P < 0.001) in heavy smokers compared to non-smokers.ConclusionThese results indicate that tobacco cigarette smoking can alter the DNA methylation level at several CpGs, the status of global DNA methylation, and transcription level of the following genes “MAPK8IP3, GAA, ANXA2, PRRC2A, and PDE11A” in human spermatozoa. These findings may affect negatively semen parameters and men’s fertility.

Nephroprotective Effects of PDE3A Gene Mutations

Nephroprotective Effects of PDE3A Gene Mutations

The predatory soil bacterium Lysobacter reprograms quorum sensing system to regulate antifungal antibiotic production in a cyclic-di-GMP-independent manner

Soil bacteria often harbour various toxins to against eukaryotic or prokaryotic. Diffusible signal factors (DSFs) represent a unique group of quorum sensing (QS) chemicals that modulate interspecies competition in bacteria that do not produce antibiotic-like molecules. However, the molecular mechanism by which DSF-mediated QS systems regulate antibiotic production for interspecies competition remains largely unknown in soil biocontrol bacteria. In this study, we find that the necessary QS system component protein RpfG from Lysobacter, in addition to being a cyclic dimeric GMP (c-di-GMP) phosphodiesterase (PDE), regulates the biosynthesis of an antifungal factor (heat-stable antifungal factor, HSAF), which does not appear to depend on the enzymatic activity. Interestingly, we show that RpfG interacts with three hybrid two-component system (HyTCS) proteins, HtsH1, HtsH2, and HtsH3, to regulate HSAF production in Lysobacter. In vitro studies show that each of these proteins interacted with RpfG, which reduced the PDE activity of RpfG. Finally, we show that the cytoplasmic proportions of these proteins depended on their phosphorylation activity and binding to the promoter controlling the genes implicated in HSAF synthesis. These findings reveal a previously uncharacterized mechanism of DSF signalling in antibiotic production in soil bacteria.

Evaluation of Serum/Urine Genomic and Metabolomic Profiles to Improve the Adherence to Sildenafil Therapy in Patients with Erectile Dysfunction.

Type V-phosphodiesterase-inhibitors (PDE5i) are the first choice drugs in the treatment of erectile dysfunction (ED), being effective in 60–70% of patients. However, approximately 50% of patients per year discontinue the treatment with PDE5i after reporting poor drug efficacy or major adverse drug reactions (ADR). To identify early markers of efficacy/safety for the treatment of ED with PDE5i, the basal clinical characteristics of patients, integrated with metabolomics analysis of serum and urine and genomic data, were here correlated with the PDE5i efficacy and the occurrence of ADR upon administration. Thirty-six males with new diagnosis of ED were consecutively recruited and characterized at baseline for anthropometrics, blood pressure, blood glucose, lipid profile, serum levels of thyroid/sex hormones and erectile function evaluated by IIEF-15 questionnaire. Targeted Next Generation Sequencing (NGS) was applied to genes involved in PDE5i pharmacodynamics and pharmacokinetics. Fasting metabolic profiles of serum and urine were assessed by nuclear magnetic resonance (NMR)-based metabolomics analysis. Patients were prescribed on-demand therapy with Sildenafil oro-dispersible film and followed-up after 3 months from recruitment. Baseline data were compared with IIEF-15 score at follow-up and with the occurrence of ADR recorded by a dedicated questionnaire. Twenty-eight patients were finally included in the analysis. Serum LDL-cholesterol levels were increased in those reporting ADR (143.3 ± 13.2 mg/dl ADR vs. 133.1 ± 12.4 mg/dl No ADR; p = 0.046). NGS data showed that specific variants of PDE11A and CYP2D7 genes were more represented in drug responders (both relative risk = 2.7 [0.9–5.1]; p = 0.04). NMR-based metabolomics showed the highest association between serum LDL-cholesterol metabolites and the occurrence of ADR (Hazard ratio = 17.5; p = 0.019). The association between lipid profile and the ADR pattern suggests major cues in the tailoring of ED therapy with PDE5i.

Sex-Specific Effects of Daily Tadalafil on Contraction Kinetics of the Diabetic Heart. The RECOGITO Randomized, Double-Blind, Placebo-Controlled Trial

Background: Cardiovascular disease is the leading cause of morbidity and mortality in type 2 diabetes (T2DM) patients. Cyclic GMP-phosphodiesterase type 5 (PDE5) inhibition was shown to counteract maladaptive cardiac changes triggered by diabetes in some studies. Our aim was to assess sex differences in cardiac remodeling after PDE5 inhibition in patients with diabetic cardiomyopathy (DCM). Methods: We performed a 20-week, double-blind, randomized, placebo-controlled trial. Men and women (45–80 years) with controlled T2DM and echocardiographic (ECG) signs of cardiac remodeling were randomly assigned (1:1) to placebo or tadalafil 20 mg once daily. The primary outcome was analyzing the sex-difference in cardiac torsion change, from baseline to 20 weeks. Secondary outcomes included changes in cardiovascular, metabolic, immune and renal function. Efficacy analyses included all patients who received at least one dose of treatment. Findings: Between May 2014 and July 2018, we screened 220 diabetic subjects; 122 met the inclusion criteria and were randomized to tadalafil (n=61) or placebo (n=61). At 20 weeks, the sex-by-treatment interaction documented an improvement in cardiac torsion [-3·40°(-5·96;-0·84, p =0·011)], paralleled by a consensual increase in fiber shortening, in men but not women. Biomarkers of cardiovascular remodeling , titin and hsa-miR-199-5p, improved accordingly. In both sexes, tadalafil reduced TGF-beta and improved albuminuria, renal artery’s resistive index, Klotho , and symmetric-di-methyl-arginine markers . Five months of 20 mg daily tadalafil in patients with DCM was proven safe. The most common adverse reactions were myalgia (9[14·5%]), gastric reflux (6[9·7%]), headache (4[6·4%]) and flushing (2[3·8%]); one SAE occurred in the placebo arm. Interpretation: Continuous PDE5 inhibition could represent a new treatment strategy to target cardiac and renal complications of T2DM, with a different tissue-specific response in men and women. Klotho and hsa-miR-199-5p appear as novel players linking renal disease to DCM progression. Trial Registration: NCT01803828. Funding Statement: Italian Ministry of University and Research, SIR RBSI141LY2. Declaration of Interests: Prof. Isidori reports personal fees from Takeda; non-financial support from Takeda and Ipsen; and grants from Shire and Pfizer outside the submitted work; Prof. Pozzilli reports research contracts and consulting from Eli Lilly, Sanofi, Merck, Merck Sharpt Dohme, Astra Zeneca, Medtronic, Abbott; Dr. Defeudis reports grants from Ibsa, personal fees from Abbott, grants from Novo Nordisk, grants from Kyowa Kirin , personal fees from Roche, outside the submitted work; Prof. Badagliacca reports personal fees from Bayer, personal fees from MSD, personal fees from Dompe, personal fees from GSK, personal fees from Ferrer, personal fees from United Therapeutics, personal fees from Galenica, personal fees from Janssen, outside the submitted work; all others have nothing to disclose. Ethics Approval Statement: The study was performed in the Policlinico Umberto I in Rome (Italy) and approved by the local ethical review board (3083/14), published on public registries (NCT01803828, EUDRACT 2014-000077-39), and conducted under the Declaration of Helsinki and good clinical practice.

Structure of the Visual Signaling Complex between Transducin and Phosphodiesterase 6

Heterotrimeric G proteins communicate signals from activated G protein-coupled receptors to downstream effector proteins. In the phototransduction pathway responsible for vertebrate vision, the G protein-effector complex is composed of the GTP-bound transducin α subunit (GαT·GTP) and the cyclic GMP (cGMP) phosphodiesterase 6 (PDE6), which stimulates cGMP hydrolysis, leading to hyperpolarization of the photoreceptor cell. Here we report a cryo-electron microscopy (cryoEM) structure of PDE6 complexed to GTP-bound GαT. The structure reveals two GαT·GTP subunits engaging the PDE6 hetero-tetramer at both the PDE6 catalytic core and the PDEγ subunits, driving extensive rearrangements to relieve all inhibitory constraints on enzyme catalysis. Analysis of the conformational ensemble in the cryoEM data highlights the dynamic nature of the contacts between the two GαT·GTP subunits and PDE6 that supports an alternating-site catalytic mechanism.

Phosphodiesterase Type 5 Inhibitors and Risk of Skin Cancers in Men: A Meta-Analysis and Trial Sequential Analysis Involving 7,479,852 Subjects.

PurposeWe conducted a systematic review and meta-analysis to quantify the association between phosphodiesterase type 5 inhibitors (PDE5Is) use and skin cancers and we also examined whether down-expression of the PDE5A gene was related to worse prognosis for malignant melanoma (MM) patients.Materials and MethodsThe PubMed, Cochrane Library, Web of Science, EMBASE, and ClinicalTrails.gov databases were searched. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to evaluate the association between PDE5Is use and risk of skin cancers. Cumulative meta-analysis and trial sequential analysis (TSA) were also conducted. Survival outcomes were analyzed online.ResultsAfter pooling all 8 eligible studies comprising 7,479,852 subjects, we found that PDE5Is use was significantly associated with slightly increased risk of developing MM (OR: 1.13, 95% CI: 1.05 to 1.21, I2=67.1%), basal cell carcinoma (OR: 1.16, 95% CI: 1.13 to 1.19, I2=49.6%), and squamous cell carcinoma (OR: 1.07, 95% CI: 1.01 to 1.13, I2=0.0%). Totally, PDE5Is increased the risk of developing skin cancers (OR: 1.13, 95% CI: 1.09 to 1.17, I2=70.8%). TSA results showed that the sample size was enough to reach a positive conclusion.ConclusionsThe use of PDE5Is may be slightly associated with increased risk of developing skin cancers. There should be a balance between drug benefits and potential safety issues. However, the pooled results should be considered tentative until confounding factors such as sun exposure and lifestyle are well-controlled in further studies.

Identification of Key Genes and Pathways Associated with Age-Related Macular Degeneration.

Age-related macular degeneration (AMD) is the leading cause of severe, permanent vision loss among the elderly in the developed world. The cellular and molecular pathogenesis of initiation and development of AMD remain poorly delineated. The limited resources of the human AMD RPE/choroid tissues impeded the extensive study of the disease. To better understand the molecular and pathway changes in human AMD RPE/choroid tissues, we searched the literature and found three independent studies using high-throughput technology to analyze gene expression in 54 human AMD RPE/choroid tissues and 46 age-matched healthy controls. We downloaded these data, pooled them together, and reanalyzed the difference between molecular and pathways by the Ingenuity Pathway Analysis (IPA) database. Totally, 353 differentially expressed genes (DEGs) were identified, among which 181 genes were downregulated and 172 genes were upregulated in RPE/choroid of AMD patients. Furthermore, several significantly enriched biological processes, including cancer, organismal injury and abnormalities, and ophthalmic disease, were identified associated with these DEGs. By analysis of canonical pathway, the phototransduction pathway and atherosclerosis signaling were the top two significant canonical pathways altered in RPE/choroid tissues in human AMD. As expected, several ophthalmic disease-related molecules, including RHO, PDE6A, 3′,5′-cyclic-GMP phosphodiesterase, and G protein alpha, were in the central nodes of disease network. The bioinformatics technology combined with the existing high-throughput data was applied to evaluate the underlying key genes and pathways in human AMD tissues, which may predict downstream and upstream biological processes and identify potential therapeutic intervention targets in human AMD.

Whole-exome sequencing identifies a de novo PDE3A variant causing autosomal dominant hypertension with brachydactyly type E syndrome: a case report

BackgroundAutosomal dominant hypertension with brachydactyly type E syndrome caused by pathogenic variants in the PDE3A gene was first reported in 2015. To date, there are only a few reports of this kind of syndrome. Other patients still lack a genetic diagnosis.Case presentationWhole-exome sequencing was performed in an 18-year-old female proband with a clinical diagnosis of hypertension with brachydactyly syndrome. Quantitative real-time PCR was used to identify pathogenic copy number variations (CNVs). After bioinformatics analysis and healthy control database filtering, we revealed a heterozygous missense PDE3A variant (c.1346G > A, p.Gly449Asp). The variant was absent in the ExAC database and located in a highly evolutionarily conserved cluster of reported PDE3A pathogenic variants. Importantly, this variant was predicted to affect protein function by both SIFT (score = 0) and PolyPhen-2 (score = 1). After Sanger sequencing, the variant was determined to be absent in the healthy parents of the proband as well as 800 ethnically and geographically matched healthy controls.ConclusionWe present a report linking a de novo PDE3A variant to autosomal dominant hypertension with brachydactyly type E syndrome.