Vascular endothelial growth factor-A gene polymorphism is associated with congenital renal lesions in children with urinary tract infections.

AIM: This study investigated the relationship between vascular endothelial growth factor-A (VEGF-A)-460C/T functional gene polymorphism and renal parenchymal lesions, vesicoureteral reflux and other urinary tract abnormalities in children with a urinary tract infection (UTI). METHODS: VEGF-A-460C/T gene polymorphism was investigated with restriction length polymorphism analysis in 76 children with their first UTI and in 63 controls without infections. Genotype and allele frequencies were compared between children with UTIs and controls and between different groups with UTIs. RESULTS: The VEGF-A-460C/T genotype frequencies differed significantly between those with and without renal parenchymal lesions in the UTI cohort. Allele C homozygosity was significantly more common in those with renal parenchymal lesions (36.6% versus 8.7%, p = 0.007). A separate analysis showed that allele C was associated with lesions compatible with hypodysplasia, rather than with focal ones associated with infections, with an odds ratio of 11.55 and 95% confidence interval of 3.03-43.9 (p = 0.0001). No significant differences in genotypes or allele frequencies were found between children with and without reflux or other urinary tract anomalies. CONCLUSION: In children with UTIs, C allele polymorphism of the VEGF-A gene was associated with hypodysplastic renal parenchymal lesions, which were possibly congenital and existed before the infection.

Clinical and molecular genetics of the phosphodiesterases (PDEs).

Cyclic nucleotide phosphodiesterases (PDEs) are enzymes that have the unique function of terminating cyclic nucleotide signaling by catalyzing the hydrolysis of cAMP and GMP. They are critical regulators of the intracellular concentrations of cAMP and cGMP as well as of their signaling pathways and downstream biological effects. PDEs have been exploited pharmacologically for more than half a century, and some of the most successful drugs worldwide today affect PDE function. Recently, mutations in PDE genes have been identified as causative of certain human genetic diseases; even more recently, functional variants of PDE genes have been suggested to play a potential role in predisposition to tumors and/or cancer, especially in cAMP-sensitive tissues. Mouse models have been developed that point to wide developmental effects of PDEs from heart function to reproduction, to tumors, and beyond. This review brings together knowledge from a variety of disciplines (biochemistry and pharmacology, oncology, endocrinology, and reproductive sciences) with emphasis on recent research on PDEs, how PDEs affect cAMP and cGMP signaling in health and disease, and what pharmacological exploitations of PDEs may be useful in modulating cyclic nucleotide signaling in a way that prevents or treats certain human diseases.

Activation of cyclic AMP signaling leads to different pathway alterations in lesions of the adrenal cortex caused by germline PRKAR1A defects versus those due to somatic GNAS mutations.

CONTEXT: The overwhelming majority of benign lesions of the adrenal cortex leading to Cushing syndrome are linked to one or another abnormality of the cAMP or protein kinase pathway. PRKAR1A-inactivating mutations are responsible for primary pigmented nodular adrenocortical disease, whereas somatic GNAS activating mutations cause macronodular disease in the context of McCune-Albright syndrome, ACTH-independent macronodular hyperplasia, and, rarely, cortisol-producing adenomas. OBJECTIVE AND DESIGN: The whole-genome expression profile (WGEP) of normal (pooled) adrenals, PRKAR1A- (3) and GNAS-mutant (3) was studied. Quantitative RT-PCR and Western blot were used to validate WGEP findings. RESULTS: MAPK and p53 signaling pathways were highly overexpressed in all lesions against normal tissue. GNAS-mutant tissues were significantly enriched for extracellular matrix receptor interaction and focal adhesion pathways when compared with PRKAR1A-mutant (fold enrichment 3.5, P < 0.0001 and 2.1, P < 0.002, respectively). NFKB, NFKBIA, and TNFRSF1A were higher in GNAS-mutant tumors (P < 0.05). Genes related to the Wnt signaling pathway (CCND1, CTNNB1, LEF1, LRP5, WISP1, and WNT3) were overexpressed in PRKAR1A-mutant lesions. CONCLUSION: WGEP analysis revealed that not all cAMP activation is the same: adrenal lesions harboring PRKAR1A or GNAS mutations share the downstream activation of certain oncogenic signals (such as MAPK and some cell cycle genes) but differ substantially in their effects on others.

In vitro studies of novel PRKAR1A mutants that extend the predicted RIα protein sequence into the 3'-untranslated open reading frame: proteasomal degradation leads to RIα haploinsufficiency and Carney complex.

BACKGROUND: Carney complex (CNC) is a multiple endocrine neoplasia syndrome due to inactivating mutations in the PRKAR1A gene that codes for type Iα regulatory (RIα) subunit of protein kinase A. Most PRKAR1A mutations are subject to nonsense mRNA decay (NMD) and, thus, lead to haploinsufficiency. METHODS AND SETTING: Patient phenotyping for CNC features and DNA, RNA, protein, and transfection studies were carried out at a research center. RESULTS: We describe in unrelated kindreds with CNC four naturally occurring PRKAR1A mutations (1055del4, 1067del4ins5, 1076delTTins13, and 1142del4) that are predicted to escape NMD because they are located in the last coding exon of the gene. The phenotype of CNC was not different from that in other patients with the condition, although the number of patients was small. Each of the mutations caused a frameshift that led to a new stop codon into the 3' untranslated open reading frame, predicting an elongated protein that, however, was absent in patient-derived cells. After site-directed mutagenesis, in vitro transcription, and cell-free translation experiments, the expected size mutant proteins were present. However, when the mutant constructs were transfected in adrenal (NCI-295), testicular (N-TERA), and embryonic (HEK293) cells and despite the presence of the mutant mRNA, Western blot analysis indicated that there were no longer proteins. The subsequent application of proteasome inhibitors to cells transfected with the mutant constructs led to the detection of the aberrant proteins, although a compound that affects protein folding had no effect. The wild-type protein was also decreased in both patient-derived cells and/or tissues as well as in the in vitro systems used in this study. CONCLUSIONS: This was the first demonstration of proteasomal degradation of RIα protein variants leading to PRKAR1A haploinsufficiency and CNC, adding protein surveillance to NMD in the cellular mechanisms overseeing RIα synthesis. In agreement with the molecular data, CNC patients bearing PRKAR1A defects that extend the open reading frame did not have a different phenotype, although this has to be confirmed in a larger number of patients.

Integrated genomic analysis of nodular tissue in macronodular adrenocortical hyperplasia: progression of tumorigenesis in a disorder associated with multiple benign lesions.

CONTEXT: Massive macronodular adrenocortical disease or ACTH-independent macronodular adrenal hyperplasia (AIMAH) is a clinically and genetically heterogeneous disorder. OBJECTIVE AND DESIGN: Whole-genome expression profiling and oligonucleotide array comparative genomic hybridization changes were analyzed in samples of different nodules from the same patients with AIMAH. Quantitative RT-PCR and staining were employed to validate the mRNA array data. RESULTS: Chromosomal gains were more frequent in larger nodules when compared with smaller nodules from the same patients. Among the 50 most overexpressed genes, 50% had a chromosomal locus that was amplified in the comparative genomic hybridization data. Although the list of most over- and underexpressed genes was similar between the nodules of different size, the gene set enrichment analysis identified different pathways associated with AIMAH that corresponded to the size; the smaller nodules were mainly enriched for metabolic pathways, whereas p53 signaling and cancer genes were enriched in larger nodules. Confirmatory studies demonstrated that BCL2, E2F1, EGF, c-KIT, MYB, PRKCA, and CTNNB1 were overexpressed in the larger nodules at messenger and/or protein levels. Chromosomal enrichment analysis showed that chromosomes 20q13 and 14q23 might be involved in progression of AIMAH from smaller to larger tumors. CONCLUSION: Integrated transcriptomic and genomic data for AIMAH provides supporting evidence to the hypothesis that larger adrenal lesions, in the context of this chronic, polyclonal hyperplasia, accumulate an increased number of genomic and, subsequently, transcript abnormalities. The latter shows that the disease appears to start with mainly tissue metabolic derangements, as suggested by the study of the smaller nodules, but larger lesions showed aberrant expression of oncogenic pathways.

Basic life support skill retention by medical students: a comparison of two teaching curricula.

AIM: In December 2005 the new guidelines for resuscitation were released and a new curriculum for the teaching of basic life support (BLS) was adopted. The aim of the present study was to investigate the effectiveness of the new guidelines and teaching curriculum on the BLS skill retention of medical students 1 year following their initial training. METHODS: The study was conducted in two consecutive academic years and compared BLS skill retention of two groups of medical students in their fourth year of medicine. The first group (group A) was taught the old guidelines with the old curriculum in the year 2005 and was re-assessed in 2006, and the second group (group B) was taught the new guidelines with the new curriculum in the year 2006 and was re-assessed in 2007. RESULTS: Significantly more students in group B assessed signs of life, located the compression area correctly and performed good quality chest compressions compared with the group taught the old guidelines with the old curriculum. CONCLUSIONS: The most important BLS skill, good quality chest compressions, was retained by significantly more students who were taught the new resuscitation guidelines according to the new curriculum.

MicroRNA signature in massive macronodular adrenocortical disease and implications for adrenocortical tumourigenesis.

PURPOSE: Massive macronodular adrenocortical disease (MMAD) may be caused by aberrant microRNA expression. To determine the microRNA profile in MMAD and identify putative microRNA-gene target pairs involved in adrenal tumourigenesis. EXPERIMENTAL DESIGN: We performed microRNA microarray analysis in 10 patients with ACTH-independent Cushing syndrome caused by MMAD (ages 39-60 years) and four normal adrenal cortex samples were used as controls. Microarray data were validated by real-time polymerase chain reaction (qRT-PCR). Identification of potential microRNA-gene target pairs implicated in MMAD pathogenesis has been performed by integrating our microRNA data with previously obtained cDNA microarray data. Experimental validation of specific microRNA gene targets was performed by transfection experiments and luciferase assay. RESULTS: A total of 37 microRNAs were differentially expressed between MMAD and normal tissues; 16 microRNAs were down-regulated, including miR-200b and miR-203, whereas 21 microRNAs were up-regulated, miR-210 and miR-484 among them. Comparison of microRNA data with different clinicopathological parameters revealed miR-130a and miR-382 as putative diagnostic MMAD markers. Interestingly, we detected miR-200b targeting directly Matrin 3 (MATR3) expression in an adrenocortical cancer cell line (H295R). CONCLUSIONS: MicroRNAs appear to have distinct regulatory effects in MMAD, including an association with clinical presentation and severity of the disease, expressed by the degree of hypercortisolism. This is the first investigation of microRNAs in MMAD, a disease with complex pathogenesis; the data indicate that specific microRNAs such as miR-200b may play a significant role in MMAD formation and/or progression.

Association of the M1V PRKAR1A mutation with primary pigmented nodular adrenocortical disease in two large families.

BACKGROUND: Carney complex (CNC) is a familial multiple neoplasia syndrome frequently associated with primary pigmented nodular adrenocortical disease (PPNAD), a bilateral form of micronodular adrenal hyperplasia that leads to Cushing's syndrome (CS). Germline PRKAR1A mutations cause CNC and only rarely isolated PPNAD. PATIENTS AND METHODS: PRKAR1A mutation analysis in two large families with CS and no other CNC manifestations demonstrated a M1V germline mutation; a total of 21 asymptomatic individuals were screened, and mutation carriers were evaluated for CNC. The mutation was expressed in vitro and functionally tested for its effects on protein kinase A function. RESULTS: Presymptomatic testing identified five first-degree relatives who were M1V carriers and who were all diagnosed with subclinical, mild CS at ages ranging from 20-56 yr. There were no other signs of CNC. In a cell-free system, we detected a shorter compared with the wild-type type 1alpha regulatory subunit of protein kinase A (PRKAR1A) protein (43 kDa). This was not identified in cell lines from the patients or in transfection experiments in HEK293 cells that showed no detectable PRKAR1A protein from the M1V-bearing constructs. In these cells, the mutant mRNA was expressed in a 1:1 ratio. CONCLUSION: In two large families, the M1V PRKAR1A mutation resulted in a PPNAD-only phenotype with significant variability both in terms of age of onset and clinical severity. Expression studies showed a unique effect of this sequence change. This study has implications for genetic counseling of carriers of this PRKAR1A mutation and patients with CNC and PPNAD and for the study of PRKAR1A-related tumorigenesis.

Abnormalities of cAMP signaling are present in adrenocortical lesions associated with ACTH-independent Cushing syndrome despite the absence of mutations in known genes.

CONTEXT: Bilateral adrenal hyperplasias (BAHs) may be caused by mutations of genes that code for molecules that participate in cAMP signaling. Little is known about cAMP signaling in adrenal lesions associated with ACTH-independent Cushing syndrome (AICS) that do not harbor mutations in known genes. OBJECTIVE: We assessed the cAMP-signaling pathway by enzymatic and molecular studies. DESIGN: Samples from 27 patients (ages 5-60 years) were studied and compared with normal adrenocortical tissue (n=4) and aldosterone-producing adenomas (APA, n=5). All samples were sequenced for GNAS, PRKAR1A, PDE11A, and PDE8B sequencing defects. cAMP levels and binding, protein kinase A, and phosphodiesterase (PDE) activities were assayed. Immunohistochemistry was used for certain studies and the phosphorylation status of CREB was studied. PATIENTS: A total of 36 samples from patients were used. RESULTS: Cortisol-producing adenomas (CPAs) and other lesions that were GNAS, PRKAR1A, PDE11A, and PDE8B gene mutation-negative were compared with PRKAR1A mutation-positive lesions, normal tissue, and APAs; abnormalities of the cAMP-signaling pathway were found in both BAHs and CPAs. Interestingly, mutation-negative CPAs had significantly decreased PDE activity. CONCLUSION: Lesions of the adrenal associated with AICS, independently of their GNAS, PRKAR1A, PDE11A, and PDE8B mutation status, have functional abnormalities of cAMP signaling. It is probable that epigenetic events or additional defects of genes involved in this pathway are responsible for this phenomenon.

MicroRNA signature of primary pigmented nodular adrenocortical disease: clinical correlations and regulation of Wnt signaling.

MicroRNAs comprise a novel group of gene regulators implicated in the development of different types of cancer; however, their role in primary pigmented nodular adrenocortical disease (PPNAD) has not been investigated. PPNAD is a bilateral adrenal hyperplasia often associated with Carney complex, a multiple neoplasia syndrome; both disorders are caused by protein kinase A (PKA) regulatory subunit type 1A (PRKARIA)-inactivating mutations. We identified a 44-microRNA gene signature of PPNAD after comparing PPNAD with normal adrenal samples. Specifically, 33 microRNAs were up-regulated and 11 down-regulated in PPNAD relative to normal tissues. These results were validated by stem loop real-time PCR analysis. Comparison of microRNA microarray data with clinicopathologic variables revealed a negative correlation (r = -0.9499) between let-7b expression and cortisol levels in patients with PPNAD. Integration of microRNA microarray with serial analysis of gene expression data together with bioinformatic algorithm predictions revealed nine microRNA-gene target pairs with a potential role in adrenal pathogenesis. Using a PPNAD cell line, we showed that miR-449 was up-regulated and identified its direct target, WNT1-inducible signaling pathway protein 2 (WISP2); in addition, pharmacologic inhibition of PKA resulted in the up-regulation of miR-449 leading to the suppression of WISP2. Overall, we investigated, for the first time, the microRNA profile and its clinical significance in PPNAD; these data also suggest that PKA, via microRNA regulation, affects the Wnt signaling pathway, which through expression and clinical studies is suspected to be a primary mediator of PRKAR1A-related tumorigenesis.