Abstract: A 10-year-old boy underwent a computed tomography (CT) scan for left flank pain following a fall. Imaging demonstrated a 5 cm left upper pole renal mass. Partial nephrectomy revealed metanephric adenofibroma, a benign stromal-epithelial tumor thought to represent a hyperdifferentiated, mature form of Wilms' tumor. We briefly discuss the histopathology and management of this rare tumor.
Abstract: Nutrient Amino acid Transporters (NATs) of SoLute Carrier family 6 (SLC6) mediate uptake of essential amino acids in mammals and insects. Phylogenomic analysis of the Caenorhabditis elegans (Ce) SLC6 family identifies 5 genes paralogous to an insect-specific NAT subfamily. Here we cloned and characterized the first representative of the identified nematode-specific transporters, SNF-5. SNF-5 mediates broad spectrum cation-coupled transport of neutral amino acids with submillimolar affinities and stoichiometry of 1AA:1Na(+), except for 1L-Pro:2 Na(+). Unexpectedly, it transports acidic L-Glu(-) and L-Asp(-) (AA (-)1:3Na(+)), revealing it to be the first member of a new B(0,-) system among characterized SLC6 transporters. This activity correlates with a unique positively charged His(+) 377 in the substrate-binding pocket. snf-5 promoter-driven EGFP labels intestinal cells INT1-9 and three pairs of amphid sensory neurons: ASI, ADF, and ASK. These cells are intimately involved in control of dauer diapause, development, metabolism, and longevity. The snf-5 deletion mutants do not show apparent morphological disorders, but increase dauer formation while reducing dauer maintenance upon starvation. Overall, our studies characterized the first nematode-specific NAT and revealed important structural and functional aspects of this transporter. In addition to the predictable role in alimentary amino acid absorption, our results indicate possible neuronal roles of SNF-5 as an amino acid provider to specific neuronal functions, including sensing of amino acid availability.
Abstract: Influenza infection induces an increase in the level of indoleamine 2, 3-dioxygenase (IDO) activity in the lung parenchyma. IDO is the first and rate limiting step in the kynurenine pathway where tryptophan is reduced to kynurenine and other metabolites. The depletion of tryptophan, and production of associated metabolites, attenuates the immune response to infection. The impact of IDO on the primary immune response to influenza virus infection was determined using the IDO inhibitor 1-methyl-D, L-tryptophan (1MT). C57BL/6 mice treated with 1MT and infected with A/HKx31 influenza virus had increased numbers of activated and functional CD4+, influenza-specific CD8+ T cells, and effector memory cells in the lung. Inhibition of IDO increased the Th1 response in CD4+ T cells as well as enhanced the Th17 response. These studies show that inhibition of IDO engenders a more robust T cell response to influenza virus, and suggests an approach for enhancing the immune response to influenza vaccination by facilitating increased influenza-specific T cell response.
Abstract: The 2009 swine-origin pandemic H1N1 (pH1N1) influenza virus transmitted and caused disease in many individuals immune to pre-2009 H1N1 influenza virus. While extensive studies on antibody-mediated pH1N1 cross-reactivity have been described, few studies have focused on influenza-specific memory T cells. To address this, the immune response in pre-2009 H1N1 influenza-immune mice was evaluated after pH1N1 challenge and disease pathogenesis was determined. The results show that despite homology shared between pre-2009 H1N1 and pH1N1 strains, the effector memory T cell response to pre-2009 H1N1 was generally ineffective, a finding that correlated with lung virus persistence. Additionally, pH1N1 challenge generated T cells reactive to new pH1N1 epitopes. These studies highlight the importance of vaccinating against immunodominant T cell epitopes to provide for a more effective strategy to control influenza virus through heterosubtypic immunity.
Abstract: Like most natural product libraries animal venoms have long been recognized as potentially rich source of biologically active molecules with the potential to be mined for the discovery of drugs, drug leads and/or biosimilars. In this work we demonstrate as a proof of concept a novel approach to explore venoms for potential biosimilarity to other drugs based on their ability to alter the transcriptomes of test cell lines followed by informatic searches and Connectivity Mapping to match the action of the venom on the cell gene expression to that of other drugs in the Connectivity Map (C-Map) database. As our test animal venom we chose Heloderma suspectum venom (Gila monster) since exendin-4, a glucagon-like peptide 1 receptor agonist, isolated from the venom is currently on the market to treat type 2 diabetes. The action of Byetta(®) (exentide, synthetic exendin-4), was also used in transcriptome studies. Analysis of transcriptomes from cells treated with the venom or the drug showed similarities as well as differences. The former case was primarily attributed to the fact that Gila monster venom likely contains a variety of biologically active molecules that could alter the MCF7 cell transcriptome compared to that of the single perturbant Byetta(®). Using Ingenuity Pathway Analysis software, insulin-like growth factor 1 signaling was identified in the category of "Top Canonical Pathways" for both the venom and Byetta(®). In the category of "Top Molecules" up-regulated, both venom and Byetta(®) shared IL-8, cyclic AMP-dependent transcription factor 3 (ATF-3), neuron-derived orphan receptor 1 (NR4A3), dexamethasone-induced Ras-related protein 1 (RASD1) and early growth response protein 1, (EGR-1) all with potential relevance in diabetes. Using Connectivity Mapping, Gila monster venom showed positive correlation with 1732 instances and negative correlation with 793 instances in the Connectivity database whereas Byetta(®) showed positive correlation with 1692 instances and negative correlation with 868 instances. Interestingly, the Gila monster venom and Byetta(®) both showed positive correlation with the anti-diabetic drugs troglitazone, of the thiazolidinedione class, and metformin, of the biguanide class, although Byetta(®) as a glucagon-like peptide-1 (GLP-1) agonist functions in a different manner than either of these two classes of anti-diabetic drugs. In summary, despite the fact that Gila monster venom contains a mixture of biologically active molecules, similarities in terms of perturbation of gene expression profiles on MCF7 cells were observed between the venom and the drug Byetta(®). Furthermore, using Connectivity Mapping the Gila monster venom was demonstrated to have nodes of positive correlation to several anti-diabetic drugs two of which were the same as observed with Byetta(®). Therefore, this study suggests that by using this approach novel drug activities heretofore unconsidered may be discovered in venoms using informatic tools and Connectivity Mapping.
Abstract: While Helicobacter pylori infects over 50% of the world's population, the mechanisms involved in the development of gastric disease are not fully understood. Bacterial, host and environmental factors play a role in disease outcome. To investigate the role of bacterial factors in H. pylori pathogenesis, global gene expression of six H. pylori isolates were analyzed during coculture with gastric epithelial cells. Clustering analysis of six Colombian clinical isolates from a region with low gastric cancer risk and a region with high gastric cancer risk, segregated strains based on their phylogeographic origin. 146 genes had increased expression in European strains while 350 genes had increased expression in African strains. Differential expression was observed in genes associated with motility, pathogenicity and other adaptations to the host environment. European strains had greater expression of the virulence factors, cagA, vacA and babB and were associated with increased gastric histologic lesions in patients. In AGS cells, European strains promoted significantly higher IL-8 expression compared to African strains. African strains significantly induced apoptosis whereas only one European strain significantly induced apoptosis. Our data suggest that gene expression profiles of clinical isolates can discriminate strains by phylogeographic origin and that these profiles are associated with changes in expression of the proinflammatory and protumorigenic cytokine IL-8 and levels of apoptosis in host epithelial cells. These findings support the hypothesis that bacterial factors from H. pylori strains from regions with higher gastric cancer incidence may promote increased gastric disease.
Abstract: Islet transplantation is an effective method to obtain long-term glycemic control for patients with type 1 diabetes, yet its widespread use is limited by an inadequate supply of donor islets. The hormone leptin has profound glucose-lowering and insulin-sensitizing action in type 1 diabetic rodent models. We hypothesized that leptin administration could reduce the dose of transplanted islets required to achieve metabolic control in a mouse model of type 1 diabetes. We first performed a leptin dose response study in C57Bl/6 mice with streptozotocin (STZ)-induced diabetes to determine a leptin dose insufficient to reverse hyperglycemia. Subsequently, we compared the ability of suboptimal islet transplants of 50 or 125 syngeneic islets to achieve glycemic control in STZ-diabetic C57Bl/6 mice treated with or without this dose of leptin. The dose response study revealed that leptin reverses STZ-diabetes in a dose-dependent manner. Supraphysiological leptin levels were necessary to restore euglycemia, but simultaneously increased risk of hypoglycemia, and also lost efficacy after 12 days of administration. In contrast, 1 µg/day leptin only modestly reduced blood glucose, but maintained efficacy throughout the study duration. We then administered 1 µg/day leptin to diabetic mice transplanted with 50 or 125 islets. While these islet doses were insufficient to ameliorate hyperglycemia alone, co-administration of leptin with islet transplantation robustly improved control of glucose and lipid metabolism, without increasing circulating insulin levels. This study reveals that low-dose leptin administration can reduce the number of transplanted islets required to achieve metabolic control in STZ-diabetic mice.
Abstract: The presence of a robust estrogen (E2) response system throughout heart and blood vessel tissues of vertebrates, including humans, has led to the speculation that this ubiquitous hormone may play a prominent role in the health and maintenance of the adult cardiovascular system (CVS). We previously established an embryonic zebrafish model called 'listless', which results from the inhibition of E2 synthesis by treatment with aromatase enzyme inhibitors (AI). These fish have outward symptoms similar to the human condition of congestive heart failure and tamponade. E2 replacement therapy (1) reduced the severity of cardiac sac abnormalities, (2) protected heart function, (3) prevented reduction in heart size, and (4) reduced blood vessel deterioration. Nitric oxide may be a critical downstream mediator of these events. We also demonstrate that removal of fluid around the heart increases survival of AI-treated fish. These results strongly indicate the importance of E2 in the developing CVS of the zebrafish and offer a potential model for the study of its role in CVS development, maintenance, and disease conditions.
