Age-dependent regulation of tumor-related microRNAs in the brain of the annual fish Nothobranchius furzeri

MicroRNAs are regulators of gene expression. We used miRNA-seq by the Illumina platform to quantify and compare the temporal miRNA expression profiles in the brain of a short-lived (GRZ) and a longer-lived strain (MZM) of the annual fish Nothobranchius furzeri. We used fuzzy-c-means clustering to group miRNAs with similar profiles. In MZM, we found tumor suppressors with known negative interactions with MYC and/or positive interactions with TP53 among up-regulated miRNAs (e.g. miR-23a, miR-26a/b, miR-29a/b and miR-101a) in aged animals. Conversely, we found oncogenes which are MYC targets among down-regulated miRNAs (miR-7a, members of miR cluster 17∼92). These latter were previously shown to be regulated in human replicative aging. In addition, three regulated miRNAs (miR-181c, miR-29a and miR-338) are known to be age-regulated and to globally contribute to regulation of their targets in the human brain. Therefore, there appears to be a degree of evolutionarily conservation in age-dependent miRNA expression between humans and N. furzeri. GRZ showed specific regulation of some miRNAs, notably a marked up-regulation of miR-124, a miRNA important for neuronal differentiation. The two strains differ in their miRNA expression profiles already at sexual maturity. Short lifespan in GRZ could therefore be - at least partially - due to dysregulated miRNA expression.     

Concurrent emergence of multidrug resistance and heat resistance by CTX-M-15-encoding conjugative plasmids in Klebsiella pneumoniae

A plasmid-encoded ClpK protein was recently identified as a predictor of a heat-resistant phenotype in the opportunistic pathogen Klebsiella pneumoniae. This study was undertaken to evaluate the presence of the clpK gene in extended-spectrum β-lactamase (ESBL)-producing K. pneumoniae and to assess the probable co-transfer of multi-resistance with the heat resistance phenotype. A Danish collection of 80 ESBL-producing K. pneumoniae bloodstream infection isolates was screened for clpK by colony hybridization. Nineteen isolates (24%) were positive for clpK; some of them representing major clones identified in Denmark. Among these, nine isolates belonged to a single K. pneumoniae CTX-M-15 clone with sequence type (ST)16 exhibiting a heat-resistant phenotype. This clone has a multi-hospital occurrence and has also been detected outside Denmark. Horizontal co-transfer of multiple antibiotic resistances, including the CTX-M-15 resistance determinant, and the heat resistance phenotype was observed. Thus, the clpK gene is harbored by different ESBL-producing K. pneumoniae isolates including a clone of ST16 internationally spread. The co-localization of clpK on transferable ESBL-encoding plasmids allowing co-dissemination of multiple drug resistance with bacterial heat resistance is a highly interesting phenomenon that may further complicate the prevention of spreading of certain successful clones of multi-resistant K. pneumoniae.     

Autoimmunity and T-cell subpopulations in old age

To investigate the interrelationship between T-cell-dependent immune functions and autoimmune phenomena in old age we determined T-cell subpopulations in 20 aged healthy individuals (80-96 years old) using monoclonal antibodies. These persons were also investigated as to humoral parameters such as antinuclear antibodies, rheumatoid factors (IgG-, IgA-, IgM-RF), antibodies to collagen types I-IV as well as autoantibodies to organ-specific antigens. In addition, immune complexes were determined. We found that aged individuals have an increased frequency of autoantibodies as compared to a young control population, each aged subject presenting with at least one autoantibody species. Immune complexes, however, were only rarely detected. Three individuals showed a slightly increased T-helper/T-suppressor cell ratio, four had a decreased ratio. An increased number of T-suppressor cells was significantly correlated with a lowered incidence of anticollagen antibodies. Other parameters tested by us: fibronectin, laminin, procollagen type III, C3 and C4 complement components, immunoglobulins and acid alpha 1-glycoprotein. Aged individuals have significantly higher serum levels of fibronectin, while laminin and procollagen concentrations are in the normal range. A large percentage of old individuals had increased serum levels of C3 and/or C4. The acute phase protein orosomucoid, however, was in the normal range.     

Endocrine systems in juvenile anadromous and landlocked Atlantic salmon (Salmo salar): seasonal development and seawater acclimation

The present study compares developmental changes in plasma levels of growth hormone (GH), insulin-like growth factor I (IGF-I) and cortisol, and mRNA levels of their receptors and the prolactin receptor (PRLR) in the gill of anadromous and landlocked Atlantic salmon during the spring parr-smolt transformation (smoltification) period and following four days and one month seawater (SW) acclimation. Plasma GH and gill GH receptor (GHR) mRNA levels increased continuously during the spring smoltification period in the anadromous, but not in landlocked salmon. There were no differences in plasma IGF-I levels between strains, or any increase during smoltification. Gill IGF-I and IGF-I receptor (IGF-IR) mRNA levels increased in anadromous salmon during smoltification, with no changes observed in landlocked fish. Gill PRLR mRNA levels remained stable in both strains during spring. Plasma cortisol levels in anadromous salmon increased 5-fold in May and June, but not in landlocked salmon. Gill glucocorticoid receptor (GR) mRNA levels were elevated in both strains at the time of peak smoltification in anadromous salmon, while mineralocorticoid receptor (MR) mRNA levels remained stable. Only anadromous salmon showed an increase of gill 11beta-hydroxysteroid dehydrogenase type-2 (11beta-HSD2) mRNA levels in May. GH and gill GHR mRNA levels increased in both strains following four days of SW exposure in mid-May, whereas only the anadromous salmon displayed elevated plasma GH and GHR mRNA after one month in SW. Plasma IGF-I increased after four days in SW in both strains, decreasing in both strains after one month in SW. Gill IGF-I mRNA levels were only increased in landlocked salmon after 4days in SW. Gill IGF-IR mRNA levels in SW did not differ from FW levels in either strain. Gill PRLR mRNA did not change after four days of SW exposure, and decreased in both strains after one month in SW. Plasma cortisol levels did not change following SW exposure in either strain. Gill GR, 11beta-HSD2 and MR mRNA levels increased after four days in SW in both strains, whereas only the anadromous strain maintained elevated gill GR and 11beta-HSD2 mRNA levels after one month in SW. The results indicate that hormones and receptors of the GH and cortisol axes are present at significantly lower levels during spring development and SW acclimation in landlocked relative to anadromous salmon. These findings suggest that attenuation of GH and cortisol axes may, at least partially, result in reduced preparatory upregulation of key gill ion-secretory proteins, possibly a result of reduced selection pressure for marine adaptations in landlocked salmon.     

Structural basis for activation of the complement system by component C4 cleavage

An essential aspect of innate immunity is recognition of molecular patterns on the surface of pathogens or altered self through the lectin and classical pathways, two of the three well-established activation pathways of the complement system. This recognition causes activation of the MASP-2 or the C1s serine proteases followed by cleavage of the protein C4. Here we present the crystal structures of the 203-kDa human C4 and the 245-kDa C4⋅MASP-2 substrate⋅enzyme complex. When C4 binds to MASP-2, substantial conformational changes in C4 are induced, and its scissile bond region becomes ordered and inserted into the protease catalytic site in a manner canonical to serine proteases. In MASP-2, an exosite located within the CCP domains recognizes the C4 C345C domain 60 Å from the scissile bond. Mutations in C4 and MASP-2 residues at the C345C–CCP interface inhibit the intermolecular interaction and C4 cleavage. The possible assembly of the huge in vivo enzyme–substrate complex consisting of glycan-bound mannan-binding lectin, MASP-2, and C4 is discussed. Our own and prior functional data suggest that C1s in the classical pathway of complement activated by, e.g., antigen–antibody complexes, also recognizes the C4 C345C domain through a CCP exosite. Our results provide a unified structural framework for understanding the early and essential step of C4 cleavage in the elimination of pathogens and altered self through two major pathways of complement activation.     

Outcome of thrombus aspiration in STEMI patients: a propensity score-adjusted study

The use of thrombus aspiration (TA) prior to primary percutaneous coronary intervention (PPCI) has undergone a radical change in intervention guidelines. The clinical implications, however, are still under scrutiny. This study investigated the clinical effects and outcome of TA before PPCI in patients with ST-segment elevation myocardial infarction (STEMI). Overall 1027 patients with STEMI were analyzed in this retrospective, propensity score-adjusted, multicenter study. The primary endpoints were in-hospital and long-term mortality. There were 418 patients in the TA group and 609 in the conventional PPCI group. The in-hospital mortality rate was significantly higher in the TA group (8.7 vs. 5.0%; P?=?0.03). During long-term follow-up [median follow-up duration 689 days (IQR 405–959)] the mortality rates were similar (TA 14.3%, conventional PPCI 15.0%; P?=?0.85). Survival analysis for the complete observation period revealed no significant benefit of TA [hazard ratio (HR) 1.12; 97.5% CI 0.90–0.71; P?=?0.63]. There were also no significant differences between the groups in the following secondary endpoints: composite of cardiovascular death and non-fatal reinfarction at discharge (P?=?0.39), post-PPCI thrombolysis in myocardial infarction flow-grade-3 (P?=?0.14), left ventricular ejection fraction (P?=?0.47), and non-fatal reinfarction during follow-up (P?=?0.17). Rehospitalization rate (1.82 vs. 10.3%; P?<?0.0001) and Canadian Cardiovascular Society (CCS) grading (P?=?0.02) during follow-up were significantly lower in the TA group. In our cohort the in-hospital mortality rate was significantly higher for TA patients, but during long-term follow-up the mortality rates did not differ. The incidence of rehospitalization and CCS grading were lower in the TA-treated patients.     

Baseline Results from Hawaii's Nā Mikimiki Project: A Physical Activity Intervention Tailored to Multiethnic Postpartum Women

During the postpartum period, ethnic minority women have higher rates of inactivity/under-activity than white women. The Nā Mikimiki (“the active ones”) Project is designed to increase moderate-to-vigorous physical activity over 18 months among multiethnic women with infants 2–12 months old. The study was designed to test, via a randomized controlled trial, the effectiveness of a tailored telephone counseling of moderate-to-vigorous physical activity intervention compared to a print/website materials-only condition. Healthy, underactive women (mean age = 32 ± 5.6 years) with a baby (mean age = 5.7 ± 2.8 months) were enrolled from 2008–2009 (N = 278). Of the total sample, 84% were ethnic minority women, predominantly Asian–American and Native Hawaiian. Mean self-reported baseline level of moderate-to-vigorous physical activity was 40 minutes/week with no significant differences by study condition, ethnicity, infant's age, maternal body mass index, or maternal employment. Women had high scores on perceived benefits, self-efficacy, and environmental support for exercise but low scores on social support for exercise. This multiethnic sample's demographic and psychosocial characteristics and their perceived barriers to exercise were comparable to previous physical activity studies conducted largely with white postpartum women. The Nā Mikimiki Project's innovative tailored technology-based intervention and unique population are significant contributions to the literature on moderate-to-vigorous physical activity in postpartum women.