Kinetoplastid membrane protein-11 exacerbates infection with Leishmania amazonensis in murine macrophages

In Leishmania amazonensis, kinetoplastid membrane protein-11 (KMP-11) expression increases during meta-cyclogenesis and is higher in amastigotes than in promastigotes, suggesting a role for this protein in the infection of the mammalian host. We show that the addition of KMP-11 exacerbates L. amazonensis infection in peritoneal macrophages from BALB/c mice by increasing interleukin (IL)-10 secretion and arginase activity while reducing nitric oxide (NO) production. The doses of KMP-11, the IL-10 levels and the intracellular amastigote loads were strongly, positively and significantly correlated. The increase in parasite load induced by KMP-11 was inhibited by anti-KMP-11 or anti-IL-10 neutralising antibodies, but not by isotype controls. The neutralising antibodies, but not the isotype controls, were also able to significantly decrease the parasite load in macrophages cultured without the addition of KMP-11, demonstrating that KMP-11-induced exacerbation of the infection is not dependent on the addition of exogenous KMP-11 and that the protein naturally expressed by the parasite is able to promote it. In this study, the exacerbating effect of KMP-11 on macrophage infection with Leishmania is for the first time demonstrated, implicating it as a virulence factor in L. amazonensis. The stimulation of IL-10 production and arginase activity and the inhibition of NO synthesis are likely involved in this effect.     

Trends in Prevalence of Hypertension in Brazil: A Systematic Review with Meta-Analysis

Background

The prevalence of hypertension in emerging nations was scarcely described to date. In Brazil, many population-based surveys evaluated the prevalence in cities throughout the country. However, there is no population-based nationwide study of prevalence of hypertension. In this study, we estimated the prevalence of hypertension for the country and analyzed the trends for the last three decades.

Methods

Cross-sectional and cohort studies conducted from 1980 to 2010 were independently identified by two reviewers, without language restriction, in the PubMed, Embase, LILACS, and Scielo electronic databases. Unpublished studies were identified in the Brazilian electronic database of theses and in annals of Cardiology congresses and meetings. In total, 40 studies were selected, comprising 122,018 individuals.

Results

Summary estimates of prevalence by the former WHO criteria (BP≥160/95 mmHg) in the 1980’s and 1990’s were 23.6% (95% CI 17.3–31.4%) and 19.6% (16.4–23.3%) respectively. The prevalence of hypertension by the JNC criteria (BP≥140/90 mmHg) in the 1980’s, 1990’s and 2000’s were 36.1% (95% CI 28.7–44.2%), 32.9% (29.9–36.0%), and 28.7% (26.2–31.4%), respectively (P<0.001). In the 2000’s, the pooled prevalence estimates of self-reported hypertension on telephone inquiries was 20.6% (19.0–22.4%), and of self-reported hypertension in home surveys was 25.2% (23.3–27.2%).

Conclusions

The prevalence of hypertension in Brazil seems to have diminished 6% in the last three decades, but it still is approximately 30%. Nationwide surveys by self-reporting by telephone interviews underestimate the real prevalence. Rates of blood pressure control decreased in the same period, corresponding currently to only one quarter of individuals with hypertension.     

The effect of biofouling on localized corrosion of the stainless steels N08904 and UNS S32760

Marine environment is a complex corrosive system and biofouling growth on immersed surfaces is one of the factors that influence corrosion processes. The effects of biofouling colonization on stainless steels (N08904 and UNS S32760) corrosion were investigated during 285 days. Open circuit potential (OCP) was measured in the absence (coupons isolated with meshes) and in the presence of biofouling. The dominant biofoulers were diatoms (during the first 15 days) and barnacles, filamentous macroalgae and encrusting bryozoans (from the 22nd until the end). Ennoblement in OCP values was different in the absence and in the presence of biofouling. In the absence of biofouling, OCP values remained stable at high values, while in the presence, after two to three months, OCP values decreased indicating localized corrosion development. Results indicated a significant correlation between the increase of the percent cover of encrusting bryozoans and the decrease of OCP. So far, the influence of encrusting bryozoans on corrosion process is unknown. Localized attacks that were registered were probably caused by live barnacles. Crevices were associated with barnacles' carapace and with calcareous base marginal addition. Nevertheless, a clear relation between OCP variation and crevice establishment was not detected.     

Beneficial effect of enalapril in spontaneously hypertensive rats cardiac remodeling with nitric oxide synthesis blockade

Aims . To study the efficiency of an angiotensin converting enzyme inhibitor on the blood pressure (BP) and the myocardium remodeling when spontaneously hypertensive rats (SHRs) are submitted to nitric oxide synthesis (NOs) blockade (with L-NAME) and simultaneously treated.
Methods . Young adult male SHRs were separated in four groups (n = 5) and treated for 20 days: Control, L-NAME, L-NAME+Enalapril, and Enalapril. The alterations of the BP, heart mass/body mass ratio and stereological parameters for myocytes, connective tissue and intramyocardial vessels were studied among the groups.
Results . The SHRs with NOs blockade showed a great modification of the myocardium with extensive areas of reparative and interstitial fibrosis and accentuated hypertrophy of the cardiac myocytes (cross sectional area 60% higher in animals taking L-NAME than in Control SHRs). Comparing the SHRs with NO deficiency (L-NAME group), the Control SHRs and the Enalapril treated SHRs significant differences were found in the BP and in all stereological parameters. The NO deficiency caused an important BP increment in SHRs that was partially attenuated by Enalapril. This Enalapril effect was more pronounced in Control SHRs. A significant increment of the intramyocardial vessels was observed in NO deficient SHRs and Control SHRs treated with Enalapril demonstrated by the stereology (greater microvascular densities in treated SHRs).
Conclusion . Enalapril administration showed a beneficial effect on vascular remodeling and myocardial hypertrophy in SHRs. In SHRs with NO blockade, however, the beneficial effect of Enalapril occurred only in vascular remodeling.     

Visualization of several binding sites for basic fibroblast growth factor (FGF-2) on fibroblasts by photoaffinity labeling: Evidence for intracellular complexes

The internalization of basic fibroblast growth factor (FGF-2) was studied in Chinese hamster lung fibroblasts (CCL39). Recombinant FGF-2 was derivatized with a photoactivable agent, N-hydroxysuccinimidyl-4-azido-benzoate (HSAB), iodinated, and used to visualize intracellular FGF-2-affinity-labeled molecules after internalization at 37°C. Iodinated HSAB-FGF-2 maintained the properties of natural FGF-2 such as affinity for heparin, binding to Bek and Flg receptors, interaction with high- and low-affinity binding sites, and reinitiating of DNA synthesis in CCL39 cells. Affinity-labeling experiments at 4°C with ¹²⁵I-HSAB-FGF-2 led to the detection of several FGF-cell surface complexes with apparent molecular mass of 80, 100, 125, 150, 170–180, 220, 260, and about 320 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), whereas two specific bands at 80 and 130–160 kDa were obtained using the homobifunctional cross-linking reagent, disuccinimidyl suberate. When the cells, preincubated with ¹²⁵I-HSAB-FGF-2 at 4°C and then washed, were shifted to 37°C, irradiation of the internalized labeled FGF-2 led to detection of a similar but fainted profile with one major specific band at 80 kDa. Heparitinase II treatment of the cells reduced binding of ¹²⁵I-HSAB-FGF-2 to its cell surface sites by 80% and internalization by 55%, indicating the involvement of heparan sulfate proteoglycans in these processes. Among the heparitinase-sensitive bands was the 80-kDa complex. © 1996 Wiley-Liss, Inc.     

Langerhans cells and cDC1s play redundant roles in mRNA-LNP induced protective anti-influenza and anti-SARS-CoV-2 immune responses

Nucleoside modified mRNA combined with Acuitas Therapeutics’ lipid nanoparticles (LNPs) has been shown to support robust humoral immune responses in many preclinical animal vaccine studies and later in humans with the SARS-CoV-2 vaccination. We recently showed that this platform is highly inflammatory due to the LNPs’ ionizable lipid component. The inflammatory property is key to support the development of potent humoral immune responses. However, the mechanism by which this platform drives T follicular helper (Tfh) cells and humoral immune responses remains unknown. Here we show that lack of Langerhans cells or cDC1s neither significantly affected the induction of PR8 HA and SARS-CoV-2 RBD-specific Tfh cells and humoral immune responses, nor susceptibility towards the lethal challenge of influenza and SARS-CoV-2. However, the combined deletion of these two DC subsets led to a significant decrease in the induction of PR8 HA and SARS-CoV-2 RBD-specific Tfh cell and humoral immune responses. Despite these observed defects, these mice remained protected from lethal influenza and SARS-CoV-2 challenges. We further found that IL-6, unlike neutrophils, was required to generate normal Tfh cells and antibody responses, but not for protection from influenza challenge.In summary, here we bring evidence that the mRNA-LNP platform can support the induction of protective immune responses in the absence of certain innate immune cells and cytokines.     

Interaction of hemin with quadruplex DNA

A DNA enzyme with peroxidase activity is a G-quadruplex-based DNAzyme formed by hemin and G-quadruplex DNA. Activity of peroxide DNAzymes can be influenced by the structure of quadruplex DNA. In this investigation, the interaction of hemin with T30695 G-quadruplex DNA is evaluated. Molecular dynamic simulation indicates that the binding mode of hemin to G-quadruplex DNA is end-stacking, which is consistent with absorption spectroscopy. Based on fluorescence spectroscopy, hemin ejects thiazole orange from bases of four-strand DNA. Circular dichroism spectra showed that no alteration occurs in this type of DNA structure.

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Graphical Abstract Peroxidase DNAzyme is formed by hemin and G-quadruplex DNA.