Structure of the rhesus monkey TRIM5α PRYSPRY domain, the HIV capsid recognition module

Tripartite motif protein TRIM5α blocks retroviral replication after cell entry, and species-specific differences in its activity are determined by sequence variations within the C-terminal B30.2/PRYSPRY domain. Here we report a high-resolution structure of a TRIM5α PRYSPRY domain, the PRYSPRY of the rhesus monkey TRIM5α that potently restricts HIV infection, and identify features involved in its interaction with the HIV capsid. The extensive capsid-binding interface maps on the structurally divergent face of the protein formed by hypervariable loop segments, confirming that TRIM5α evolution is largely determined by its binding specificity. Interactions with the capsid are mediated by flexible variable loops via a mechanism that parallels antigen recognition by IgM antibodies, a similarity that may help explain some of the unusual functional properties of TRIM5α. Distinctive features of this pathogen-recognition interface, such as structural plasticity conferred by the mobile v1 segment and interaction with multiple epitopes, may allow restriction of divergent retroviruses and increase resistance to capsid mutations.     

Low rate of active treatment of patients with hilar cholangiocarcinoma

Introduction

The results of surgical resection and palliative chemotherapy use in hilar cholangiocarcinoma (HC) have been well publicised but the proportion of patients able to undergo these treatments and the comparative outcomes in a population of patients with HC are less well known.

Methods

Patients with HC were identified by review of all patients undergoing percutaneous cholangiography over a nine-year period (2002–2010) in a tertiary facility. The treatment undertaken and outcomes were recorded.

Results

Overall, 68 patients were identified (37 female) with a median age of 70 years. Forty-five (66%) were treated solely by insertion of a metal stent (median survival 4.73 months) and nine (13%) also received palliative chemotherapy (median survival 13.7 months). Persisting jaundice after stent insertion was noted in 18 of 35 patients (51%) tested within one month of death. Fourteen patients (21%) underwent surgical resection (median survival 20.2 months).

Conclusions

Patients undergoing surgical resection had significantly longer survival than those receiving only a palliative stent but not compared with those also receiving palliative chemotherapy, with short-term follow-up. Only a third of patients, however, receive active treatment (surgery or chemotherapy) and improvements in long-term biliary palliation are needed.     

Bile Acid at Low pH Reduces Squamous Differentiation and Activates EGFR Signaling in Esophageal Squamous Cells in 3-D Culture

Background

Barrett's esophagus is a preneoplastic metaplasia in which the normal squamous epithelium of the esophagus changes to an intestinal, columnar phenotype due to long-term gastro-esophageal reflux. The major components of this reflux are bile and stomach acid. Previous in vitro studies on the effect of bile and acid on esophageal cells have predominantly relied on transformed esophageal squamous cells or cancer cells grown in monolayer culture.

Discussion

In this study, we expanded our previous work using an immortalized primary esophageal squamous cell line (EPC1). We demonstrate that EPC1 cells form a multi-layer, stratified epithelium when grown on polyester transwell filters in media supplemented with calcium. When exposed to short pulses of bile and pH 5, but not either condition alone, EPC1 cells demonstrate a reduction in stratification layers and reduced expression of squamous epithelium-specific genes. Bile at pH 5 also causes activation of epidermal growth factor receptor and down-stream pathways. Blocking epidermal growth factor receptor activation partially attenuates the effects of bile acid and pH 5. These results suggest that bile at low pH, but not bile or low pH alone, promotes loss of differentiation status of stratified squamous esophageal epithelium in vitro, possibly by initiating a mucosal repair response through epidermal growth factor activation.     

Myocardial morphology in cases of death from acute heart ischemic disease

The death from acute ischemic heart diseases (acute coronary insufficiency (n = 39) and acute myocardial infarction (n = 36) is accompanied by a slight increase in the thickness of the left ventricular wall with preserved normal heart weight. Microscopically, there are longer intermuscular distances, cardiomyocytic thickening, nuclear polymorphism, contractures, and destruction of myocytes and their lysis.     

Autoimmunity, spontaneous tumourigenesis, and IL-15 insufficiency in mice with a targeted disruption of the tumour suppressor gene Fus1

The Fus1 gene resides in the critical 3p21.3 human chromosomal region deleted in lung and breast cancers. Recently, the tumour suppressor properties of Fus1 were confirmed experimentally by intra-tumoural administration of Fus1 that suppressed experimental lung metastasis in mice. We generated Fus1-deficient mice that were viable, fertile, and demonstrated a complex immunological phenotype. Animals with a disrupted Fus1 gene developed signs of autoimmune disease, such as vasculitis, glomerulonephritis, anaemia, circulating autoantibodies, and showed an increased frequency of spontaneous vascular tumours. Preliminary analysis of immune cell populations revealed a consistent defect in NK cell maturation in Fus1 null mice that correlated with changes in the expression of IL-15. Injection of IL-15 into Fus1 knockout mice completely rescued the NK cell maturation defect. Based on these results, we propose the hypothesis that Fus1 deficiency affects NK cell maturation through the reduction of IL-15 production but does not directly alter their developmental capacity. Since acquired immunity was not affected in Fus1-deficient animals, we suggest a relationship between the Fus1 protein and the regulation of innate immunity via IL-15 production. The increased frequency of spontaneous cancers and the development of an autoimmune syndrome in Fus1 null mice imply that these mice could serve as a model for studying molecular mechanisms of anti-tumour immunity and autoimmunity.     

Heterozygosity of 198LEU mutant allele in glutathione peroxidase-1 gene as a risk factor of bronchial asthma associated with smoking

AIM: To investigate whether smoking has a differential effect by Pro198Leu genotypes of the glutathione peroxidase-1 (GPx1) gene on the risk of bronchial asthma (BA) in Russian population. MATERIAL AND METHODS: DNA samples from 195 asthmatics and 167 healthy volunteers were genotyped for Pro198Leu polymorphism of the GPx1 gene by polymerase chain reaction and restriction fragment length analysis. RESULTS: Smoking was significantly associated with an increased risk of non-allergic BA in males but not in females (p < 0.00001). When smoking was examined according to Prol98Leu polymorphism of the GPx1 gene, association of 198Pro/Leu genotype with susceptibility to allergic BA was found only in male smokers (odds ratio = 2.51, 95% confidence interval = 1.04 to 6.06, p = 0.04). CONCLUSION: The risk of allergic BA associated with smoking is increased in males who are heterozygous carriers for the low-activity 198Leu allele of the glutathione peroxidase-1 gene. The importance of molecular mechanisms is shown by which functional variants of antioxidant defense genes may mediate potentially oxidative effects of tobacco smoke on asthmatic phenotype.     

Intraoperative myocardial protection with extracellular cardioplegic solutions in patients with cardiac valve diseases

A hundred patients operated on under extracorporeal circulation (EC) with bicaval cannulation in the moderate general hypothermia mode were intraoperatively examined. According to the used cardioplegic solution, all the patients were divided into three groups: 1) Konsol; 2) Konsol MF; 3) St. Thomas (a control group). All the groups were matched by age, gender, the duration of myocardial ischemia (MI) (37-128 min), that of EC (52-186 min), and the nature of surgical interventions, of which mitral valve replacement amounted to 72-78%. To prepare a modified solution, 20 ml of 40% glucose, 20 units of insulin, and 200 mg of creatine phosphate (Neoton) were added to a flask containing 400 ml of Konsol. The efficiency of myocardial protection was evaluated by the data characterizing cardiac arrest and cardiac performance resumption, as well as by heart rate and the use of inotropic support in the reperfusion period. The parameters of central hemodynamics and systemic coronary blood flow, the concentrations of glucose and lactate, the blood gas and electrolyte composition of the coronary sinus (CS), myocardial oxygen consumption and the oxygen-utilizing coefficient were monitored. The cardioplegic solutions Consol and Consol MF were found to have a more effective cardioprotective activity in patients with cardiac valvular disease, operated on under EC and moderate hypothermia that St. Thomas'solution. Modification of the Consol solution by adding glucose, creatine phosphate, and insulin improves the protective effect of the solution, promoting a rapider transition of the myocardium from anaerobic to aerobic metabolism.