Lysyl-tRNA synthetase as a drug target in malaria and cryptosporidiosis

Malaria and cryptosporidiosis, caused by apicomplexan parasites, remain major drivers of global child mortality. New drugs for the treatment of malaria and cryptosporidiosis, in particular, are of high priority; however, there are few chemically validated targets. The natural product cladosporin is active against blood- and liver-stage; Plasmodium falciparum; and; Cryptosporidium parvum; in cell-culture studies. Target deconvolution in; P. falciparum; has shown that cladosporin inhibits lysyl-tRNA synthetase (; Pf; KRS1). Here, we report the identification of a series of selective inhibitors of apicomplexan KRSs. Following a biochemical screen, a small-molecule hit was identified and then optimized by using a structure-based approach, supported by structures of both; Pf; KRS1 and; C. parvum; KRS (; Cp; KRS). In vivo proof of concept was established in an SCID mouse model of malaria, after oral administration (ED; 90; = 1.5 mg/kg, once a day for 4 d). Furthermore, we successfully identified an opportunity for pathogen hopping based on the structural homology between; Pf; KRS1 and; Cp; KRS. This series of compounds inhibit; Cp; KRS and; C. parvum; and; Cryptosporidium hominis; in culture, and our lead compound shows oral efficacy in two cryptosporidiosis mouse models. X-ray crystallography and molecular dynamics simulations have provided a model to rationalize the selectivity of our compounds for; Pf; KRS1 and; Cp; KRS vs. (human); Hs; KRS. Our work validates apicomplexan KRSs as promising targets for the development of drugs for malaria and cryptosporidiosis

Report on Computers in Practice: a survey of computers in architectural practice

This is a report on the dynamic relationship between information technology (IT) and architectural practice. The report summarises the attitudes and opinions of practitioners gathered through extensive recorded interviews, and compares these attitudes and opinions with the findings of other studies. The report is compiled from the point of view of an understanding of appropriating as preceding as the model for understanding. We thereby connect what is going on in IT with concepts currently under discussion in postmodern thought and in the tradition of philosophical pragmatism. We identify several of the major options identified by practitioners in their use of IT, including practicing without computers, substituting computers for traditional tasks, delivering traditional services in an innovative way through IT, and developing new services with IT. We also demonstrate how firms are changing and are being shaped by the market for architectural services. One of the major areas of change is in how IT and related resources are managed. We also consider how the role of the practitioner as an individual in a firm is changing along with changes in IT, and how different prognoses about the future of IT in practice are influenced by certain dominant metaphors. Our conclusion is that IT is best understood and appropriated when it is seen as fitting into a dynamic field or constellation of technologies and practices. Such an orientation enables the reflective practitioner to confront what is really going on as IT interacts with practice. praxis- practice theor

A novel grid-oriented dynamic weight parameter based improved variant of Jaya algorithm

Jaya algorithm (JA) is a single-step metaheuristic optimization technique that is free from algorithm-specific parameters. Regardless of its simplicity, JA proved its effective performance against the variety of optimization algorithms (Du et al., 2018). However, like other swarm-based optimization techniques, the JA also suffers from the inadequacies of slow or premature convergence (Farah and Belazi, 2018). In this study, an improved variant of JA (IJaya) is proposed whose functioning depends on the randomly initiated bounds based grid-oriented weight parameters. Initially, aiming to balance the global exploration and local exploitation capabilities of JA, a dynamic weight parameter is introduced as a varying coefficient for the entire solution updating expression of JA. Then, to maintain the population diversity and to mitigate the complexity of parameter tuning, the introduced weight parameter is dealt with the randomly selected parameter bounds based grid-search mechanism. The proposed IJaya algorithm is benchmarked on well-known 15 unconstrained mathematical test functions, and its performance is analyzed against the standard JA, one modified variant of JA, some well-known state-of-the-art, and few newly introduced optimization algorithms. Furthermore, the non-parametric Friedman and Quade rank tests are also conducted which confirmed the superiority of proposed IJaya both in convergence rate and solution quality. The paper also presents the results obtained by IJaya in two classical structural design problems (a cantilever beam and a 3-bar truss) and a real-world electrical power engineering problem. Numerical results clearly prove the efficiency of the proposed algorithm

Interleukin-2 is Present in Human Blood Vessels and Released in Biologically Active Form by Heparanase

Interleukin-2 (IL-2) is a multifaceted cytokine with immunostimulatory and immunosuppressive properties. Our laboratory recently demonstrated that the availability of IL-2 is regulated, in part, by association with perlecan, a heparan sulfate proteoglycan. Given the abundance of perlecan in blood vessels, we asked whether IL-2 is present in vessel walls. Our results indicate that IL-2 is associated with endothelial and smooth muscle cells within the human arterial wall. This IL-2 is released by heparanase, and promotes the proliferation of an IL-2-dependent cell line. Given the presence of IL-2 in human arteries, we asked whether the large vessels of IL-2-deficient mice were normal. The aortas of IL-2-deficient mice exhibited a loss of smooth muscle cells, suggesting that IL-2 may contribute to their survival. In their entirety, these results suggest a here-to-fore unrecognized role of IL-2 in vascular biology, and have significant implications for both the immune and cardiovascular systems

Clinical and microbiologic efficacy of the piperazine-based drug lead MMV665917 in the dairy calf cryptosporidiosis model

<div><p>Cryptosporidiosis causes life-threatening diarrhea in infants, but the best available treatment is only modestly efficacious. Rodents infected with relevant <i>Cryptosporidium</i> species do not develop diarrhea, which complicates drug development. <i>Cryptosporidium parvum</i> infection of dairy calves, however, causes an illness like that seen in infants. Here, the clinical and microbiologic anti-<i>Cryptosporidium</i> efficacy of the piperazine-based compound MMV665917 was demonstrated in neonatal calves. Oral administration of MMV665917 (22 mg/kg once daily) was begun two days after the onset of severe diarrhea and continued for seven days. Treatment resulted in prompt resolution of diarrhea, and reduced total fecal oocyst shedding by ~94%. MMV665917 was useful for treatment, rather than just prophylaxis, since it was safe and effective when administered well after the onset of diarrhea. Furthermore, even though all animals received intensive supportive care, there was a strong trend towards improved secondary health outcomes, including general health, appetite, and dehydration measures amongst treated animals. These data establish MMV665917 as an outstanding lead compound for <i>Cryptosporidium</i> drug development.</p></div

Pharmacokinetic properties of CFZ.

<p>(A) Plasma concentration of CFZ or BKI-1294 in mice dosed with 20 mg/kg compound. CFZ was formulated in either corn oil (black) or MC-Tween (gray); BKI-1294 was formulated in 7% Tween 80, 3% ethanol, and 90% water (white). Data shown are mean ± SEM (n = 3). (B) Unchanged CFZ or BKI-1294 recovered in the feces of mice dosed in (A). Recovery was measured each day for three days. Data shown are mean ± SEM (n = 3).</p

A high-throughput phenotypic screen identifies clofazimine as a potential treatment for cryptosporidiosis

<div><p>Cryptosporidiosis has emerged as a leading cause of non-viral diarrhea in children under five years of age in the developing world, yet the current standard of care to treat <i>Cryptosporidium</i> infections, nitazoxanide, demonstrates limited and immune-dependent efficacy. Given the lack of treatments with universal efficacy, drug discovery efforts against cryptosporidiosis are necessary to find therapeutics more efficacious than the standard of care. To date, cryptosporidiosis drug discovery efforts have been limited to a few targeted mechanisms in the parasite and whole cell phenotypic screens against small, focused collections of compounds. Using a previous screen as a basis, we initiated the largest known drug discovery effort to identify novel anticryptosporidial agents. A high-content imaging assay for inhibitors of <i>Cryptosporidium parvum</i> proliferation within a human intestinal epithelial cell line was miniaturized and automated to enable high-throughput phenotypic screening against a large, diverse library of small molecules. A screen of 78,942 compounds identified 12 anticryptosporidial hits with sub-micromolar activity, including clofazimine, an FDA-approved drug for the treatment of leprosy, which demonstrated potent and selective in vitro activity (EC₅₀ = 15 nM) against <i>C</i>. <i>parvum</i>. Clofazimine also displayed activity against <i>C</i>. <i>hominis</i>–the other most clinically-relevant species of <i>Cryptosporidium</i>. Importantly, clofazimine is known to accumulate within epithelial cells of the small intestine, the primary site of <i>Cryptosporidium</i> infection. In a mouse model of acute cryptosporidiosis, a once daily dosage regimen for three consecutive days or a single high dose resulted in reduction of oocyst shedding below the limit detectable by flow cytometry. Recently, a target product profile (TPP) for an anticryptosporidial compound was proposed by Huston et al. and highlights the need for a short dosing regimen (< 7 days) and formulations for children < 2 years. Clofazimine has a long history of use and has demonstrated a good safety profile for a disease that requires chronic dosing for a period of time ranging 3–36 months. These results, taken with clofazimine’s status as an FDA-approved drug with over four decades of use for the treatment of leprosy, support the continued investigation of clofazimine both as a new chemical tool for understanding cryptosporidium biology and a potential new treatment of cryptosporidiosis.</p></div

CFZ is efficacious in a mouse model of acute cryptosporidiosis.

<p>Fecal oocyst recovery from IFN-γ^-/- mice commenced three days after oral delivery of <i>C</i>. <i>parvum</i> oocysts. Line graph data are weight-adjusted mean oocyst counts ± SD (n = 4); inset bar graphs are mean % recovery relative to mock-treated control mice ± SEM (n = 4). (A) Mice were infected with 10⁴ oocysts then treated orally with 10 mg/kg BKI-1294 (light gray) or CFZ (dark gray) on days 4, 5, and 6 p.i. Dotted line is the reliable limit of detection. A two-way ANOVA was conducted to determine significance between mice treated with compound vs mice treated with vehicle: * p < 0.05; ** p < 0.01. (B) Mice were infected with 10⁶ oocysts then treated orally with a single dose of 100 mg/kg CFZ on day 4. Multiple Student’s t-tests were used to determine significance between vehicle-treated and CFZ-treated mice: * p < 0.05; ** p < 0.01.</p