Further insights into biological evaluation of new anti-Trypanosoma cruzi 5-nitroindazoles

Twelve molecules from a series of 35 new 5-nitroindazole derivatives, selected from a successful primary screening on Trypanosoma cruzi epimastigotes, have been evaluated against intracellular amastigotes according to the previous results of their trypanocidal activity and unspecific cytotoxicity. 2-Benzyl-1-propyl (22), 2-benzyl-1-isopropyl (23), and 2-benzyl-1-butyl (24) 5-nitroindazolin-3-ones have inhibited the growth of amastigotes similarly to the reference drugs benznidazole and nifurtimox, inducing complete growth inhibition at concentrations lower than 8 μM (IC₅₀?<?5 μM) and accomplishing great selectivity indexes on the intracellular form of the parasite (SI?>?30). Further in vivo assays were developed only for two of the most active molecules (22 and 24), reaching significant reductions in parasitemia levels (52 % and 77 %, respectively) after their oral administration to infected mice. In addition, none of the mice in experimental and benznidazole groups died, unlike in the control group which is only treated with the vehicle. The trypanocidal properties found in some of the 5-nitroindazole derivatives assayed in the present work represent an interesting contribution to the urgent need for searching new antichagasic drugs.     

Neutrophil Dependence of Vascular Remodeling after Mycoplasma Infection of Mouse Airways

Vascular remodeling is a feature of sustained inflammation in which capillaries enlarge and acquire the phenotype of venules specialized for plasma leakage and leukocyte recruitment. We sought to determine whether neutrophils are required for vascular remodeling in the respiratory tract by using Mycoplasma pulmonis infection as a model of sustained inflammation in mice. The time course of vascular remodeling coincided with the influx of neutrophils during the first few days after infection and peaked at day 5. Depletion of neutrophils with antibody RB6-8C5 or 1A8 reduced neutrophil influx and vascular remodeling after infection by about 90%. Similarly, vascular remodeling after infection was suppressed in Cxcr2^−/− mice, in which neutrophils adhered to the endothelium of venules but did not extravasate into the tissue. Expression of the venular adhesion molecule P-selectin increased in endothelial cells from day 1 to day 3 after infection, as did expression of the Cxcr2-receptor ligands Cxcl1 and Cxcl2. Tumor necrosis factor α (TNFα) expression increased more than sixfold in the trachea of wild-type and Cxcr2^−/− mice, but intratracheal administration of TNFα did not induce vascular remodeling similar to that seen in infection. We conclude that neutrophil influx is required for remodeling of capillaries into venules in the airways of mice with Mycoplasma infection and that TNFα signaling is necessary but not sufficient for vascular remodeling.Neutrophils are key effector cells of innate immunity that rapidly arrive at sites of tissue injury to kill bacteria and interact with macrophages and other cells to orchestrate a coordinated immune cell and cytokine response to injury.^1–4 Neutrophils are involved in many inflammatory diseases of the airways and lung, including pneumonia, acute lung injury, sepsis, asthma, cystic fibrosis, bronchitis, and chronic obstructive lung disease,⁵ also contribute to tissue damage in inflammatory conditions of other organs, and play a role in arterial remodeling in atherosclerosis.⁴The signals and events that bring neutrophils to sites of inflammation are well characterized.^6–8 These include expression of endothelial cell adhesion molecules to induce rolling and firm attachment, followed by extravasation into tissues where they release cytokines and other products that can kill bacteria and promote tissue remodeling. The dominant mechanism driving neutrophil influx may be organ-specific.^9,10 Blood vessels of the microcirculation undergo numerous changes in sustained inflammation, and these include structural and functional remodeling of endothelial cells and pericytes.^11–14 Among these changes, capillaries transform into venules that support plasma leakage and leukocyte influx. The contribution of neutrophils to this remodeling is not well understood. Circumferential vessel enlargement is a prominent feature of vascular remodeling–sustained airway inflammation^15–23 and is distinct from more familiar and better-documented types of sprouting angiogenesis.²⁴We asked whether incoming neutrophils contribute to the vascular remodeling, with the thought that the initial wave of leukocyte influx could render blood vessels more efficient for leukocyte adhesion and transmigration. Although leukocyte influx is known to accompany blood vessel remodeling,^15,18,22 it is unknown whether there is a causal relationship and, if so, what is the underlying mechanism? Neutrophils are attractive candidates for contributing to vascular remodeling because they are among the first leukocytes to enter inflamed tissues^4,6,25 and can produce cytokines, growth factors, proteases, and reactive oxygen species that have profound vascular effects.^2–4,26With this background, we sought to determine whether neutrophils are essential for the vascular remodeling that occurs soon after Mycoplasma pulmonis infection, when capillaries transform into venules. In particular, we asked whether neutrophil influx coincides spatially and temporally with vascular remodeling, can vascular remodeling be prevented by neutrophil depletion, and if Cxcr2 signaling is required for the neutrophil influx that accompanies vascular remodeling?To address these questions we examined the relationship between neutrophil influx and vascular remodeling during the first week after M. pulmonis infection of the respiratory tract of mice. The approach was to compare the time course of neutrophil influx and vascular remodeling in the trachea and then determine whether the remodeling was blocked by neutrophil depletion by either of two different antineutrophil antibodies: RB6-8C5 or 1A8. We also tested whether vascular remodeling was prevented by genetic deletion of Cxcr2, which mediates the actions of the chemotactic chemokines Cxcl1 and Cxcl2, which bring neutrophils into inflamed tissues. Because previous studies have shown that vascular remodeling was inhibited by blocking tumor necrosis factor α (TNFα) signaling,¹⁹ we asked whether TNFα expression was increased in wild-type and Cxcr2^−/− mice and whether intratracheal administration of TNFα was sufficient to induce vascular remodeling similar to that seen after infection. Other studies examined the expression of the Cxcr2 ligands, Cxcl1 and Cxcl2. Together, the experiments showed that neutrophil influx was required for vascular remodeling after M. pulmonis infection, and that TNF signaling was necessary but not sufficient for vascular remodeling.     

Simple Sequence Repeats in the National Longitudinal Study of Adolescent Health: An Ethnically Diverse Resource for Genetic Analysis of Health and Behavior

Simple sequence repeats (SSRs) are one of the earliest available forms of genetic variation available for analysis and have been utilized in studies of neurological, behavioral, and health phenotypes. Although findings from these studies have been suggestive, their interpretation has been complicated by a variety of factors including, among others, limited power due to small sample sizes. The current report details the availability, diversity, and allele and genotype frequencies of six commonly examined SSRs in the ethnically diverse, population-based National Longitudinal Study of Adolescent Health. A total of 106,743 genotypes were generated across 15,140 participants that included four microsatellites and two di-nucleotide repeats in three dopamine genes (DAT1, DRD4, DRD5), the serotonin transporter, and monoamine oxidase A. Allele and genotype frequencies showed a complex pattern and differed significantly between populations. For both di-nucleotide repeats we observed a greater allelic diversity than previously reported. The availability of these six SSRs in a large, ethnically diverse sample with extensive environmental measures assessed longitudinally offers a unique resource for researchers interested in health and behavior.