<p>Shiv Nadar University is a comprehensive, multidisciplinary, research-focused, and student-centric University offering a full range of academic programs at the undergraduate, postgraduate and doctoral level. With state-of-the-art infrastructure, the University comprises of academic wings, sophisticated labs, international standard sports facilities, amphitheaters, auditorium, conference rooms and smart classrooms. The University&rsquo;s goal is to become internationally recognized for the quality of its research and creative endeavors and their applicability to improving quality of life, generating new insights and expanding the boundaries of human knowledge creativity. Committed to excellence in teaching, research and service, the University aims to serve the higher education needs of India and the world beyond.</p>

Shiv Nadar University

(SoNS) School of Natural Sciences

Malaria, one of the most severe global diseases, infects nearly 300 million people causing death of about a million population annually. Herein we have reported design, synthesis and biological evaluation of potent antimalarial compounds that target melatonin hormone as a potential pathway for the inhibition of the parasite proliferation. The molecular design is based on melatonin and indole based synthetic and natural antimalarial agents. The library of compounds was accessed via an iodine catalyzed one pot organocatalytic ring opening of 1-aryltetrahydro-β-carbolines followed by in situ imination of the resulting C2-aroyl intermediates. Inhibition of parasite growth progression (3D7 and chloroquine resistant RKL9 strain) in the presence of the tested compounds indicated that few of the compounds substantially inhibited the parasite survival and the most potent compound 2j blocked the parasite growth at the trophozoite stage. Compound 2j also disrupted the melatonin induced synchronization of the parasite culture in vitro. The active compounds were screened against melatonin receptor MT1 to demonstrate substantial binding. © 2019 Elsevier Masson SAS

Life Sciences

Chemistry

European Journal of Medicinal Chemistry

Indole based antimalarial compounds targeting the melatonin pathway: Their design, synthesis and biological evaluation

Synthetic organic molecules, which can selectively convert excess intracellular copper (Cu) ions to nanozymes with an ability to protect cells from oxidative stress, are highly significant in developing therapeutic agents against Cu-related disorder like Wilson's disease. Here, we report 1,3-bis(2-hydroxyethyl)-1H-benzoimidazole-2-selenone (1), which shows a remarkable ability to remove Cu ion from glutathione, a major cytosolic Cu-binding ligand, and thereafter converts it into copper selenide (CuSe) nanozyme that exhibits remarkable glutathione peroxidase-like activity, at cellular level of H 2 O 2 concentration, with excellent cytoprotective effect against oxidative stress in hepatocyte. Cu-driven deselenization of 1, under physiologically relevant conditions, occurred in two steps. The activation of C=Se bond by metal ion is the crucial first step, followed by cleavage of the metal-activated C=Se bond, initiated by the OH group of N-(CH 2 ) 2 OH substituent through neighboring group participation (deselenization step), resulted in the controlled synthesis of various types of Cu 2-x Se nanocrystals (NCs) (nanodisks, nanocubes, and nanosheets) and tetragonal Cu 3 Se 2 NCs, depending upon the oxidation state of the Cu ion used to activate the C=Se bond. Deselenization of 1 is highly metal-selective. Except Cu, other essential metal ions, including Mn 2+ , Fe 2+ , Co 2+ , Ni 2+ , or Zn 2+ , failed to produce metal selenide under identical reaction conditions. Moreover, no significant change in the expression level of Cu-metabolism-related genes, including metallothioneines MT1A, is observed in liver cells co-treated with Cu and 1, as opposed to the large increase in the concentrations of these genes observed in cells treated with Cu alone, suggesting the participation of 1 in Cu homeostasis in hepatocyte. © 2019 American Chemical Society.

ACS Applied Materials and Interfaces

Copper-Driven Deselenization: A Strategy for Selective Conversion of Copper Ion to Nanozyme and Its Implication for Copper-Related Disorders

Clostridium perfringens epsilon toxin (Etx) is categorized as the third most lethal bioterrorism agent by the Centers for Disease Control and Prevention (CDC), with no therapeutic counter measures available for humans. Here, we have developed a high-affinity inhibitory compound by synthesizing and evaluating the structure activity relationship (SAR) of a library of diverse glycosides (numbered 1-12). SAR of glycoside-Etx heptamers revealed exceptionally strong H-bond interactions of glycoside-4 with a druggable pocket in the oligomerization and β-hairpin region of Etx. Analysis of its structure suggested that glycoside-4 might self-aggregate to form a robust micelle-like supra-molecular complex due to its linear side-chain architecture, which was authenticated by fluorescence spectroscopy. Further, this micelle hinders the Etx monomer-monomer interaction required for oligomerization, validated by both surface plasmon resonance (SPR) and immunoblotting. This phenomenon in turn leads to blockage of pore formation. Downstream evaluation revealed that glycoside-4 effectively blocked cell death of Etx-treated cultured primary cells and maintained cellular homeostasis via disrupting oligomerization, blocking pore formation, restoring calcium homeostasis, stabilizing the mitochondrial membrane and impairing high mobility group box 1 (HMGB1) translocation from nucleus to cytoplasm. Furthermore, a single dosage of glycoside-4 protected the Etx-challenged mice and restored normal function to multiple organs. This work reports for the first time a potent, nontoxic glycoside with strong ability to occlude toxin lethality, representing it as a bio-arm therapeutic against Etx-based biological threat. © 2019. Published by The Company of Biologists Ltd

World University root node

Fulltext

DMM Disease Models and Mechanisms

A small bioactive glycoside inhibits epsilon toxin and prevents cell death

In pre-clinical models, co-existence of Human Epidermal Growth Factor Receptor-2 (HER2)-amplification and PI3K catalytic subunit (PIK3CA) mutations results in aggressive, anti-HER2 therapy-resistant breast tumors. This is not always reflected in clinical setting. We speculated that the complex interaction between the HER2 and PIK3CA oncogenes is responsible for such inconsistency. We performed series of biochemical, molecular and cellular assays on genetically engineered isogenic mammary epithelial cell lines and breast cancer cells expressing both oncogenes. In vitro observations were validated in xenografts models. We showed that H1047R, one of the most common PIK3CA mutations, is responsible for endowing a senescence-like state in mammary epithelial cells overexpressing HER2. Instead of imposing a permanent growth arrest characteristic of oncogene-induced senescence, the proteome secreted by the mutant cells promotes stem cell enrichment, angiogenesis, epithelial-to-mesenchymal transition, altered immune surveillance and acute vulnerability toward HSP90 inhibition. We inferred that the pleiotropism, as observed here, conferred by the mutated oncogene, depending on the host microenvironment, contributes to conflicting pre-clinical and clinical characteristics of HER2+, mutated PIK3CA-bearing tumor cells. We also came up with a plausible model for evolution of breast tumors from mammary epithelial cells harboring these two molecular lesions. © 2019 The Author(s). Published by Oxford University Press. All rights reserved.

Carcinogenesis

The H1047R PIK3CA oncogene induces a senescence-like state, pleiotropy and acute HSP90 dependency in HER2+ mammary epithelial cells

Malaria, caused by protozoan of genus Plasmodium, remains one of the highest mortality infectious diseases. Malaria parasites have a complex life cycle, easily adapt to their host’s immune system and have evolved with an arsenal of unique proteases which play crucial roles in proliferation and survival within the host cells. Owing to the existing knowledge of enzymatic mechanisms, 3D structures and active sites of proteases, they have been proven to be opportune for target based drug development. Here, we discuss in depth the crucial roles of essential proteases in Plasmodium life cycle and particularly focus on highlighting the atypical “structural signatures” of key parasite proteases which have been exploited for drug development. These features, on one hand aid parasites pathogenicity while on the other hand could be effective in designing targeted and very specific inhibitors for counteracting them. We conclude that Plasmodium proteases are suitable as multistage targets for designing novel drugs with new modes of action to combat malaria. Copyright © 2019 Mishra, Singh and Singh. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

Frontiers in Microbiology

Structural insights into key plasmodium proteases as therapeutic drug targets

Successful pathogenesis is a cumulative effect of the virulence factors of a pathogen and its capability to efficiently utilize the available nutrients from the host. Streptococcus pneumoniae, a Gram-positive opportunistic pathogen, may either reside asymptomatically as a nasopharyngeal commensal inside the human host or cause lethal diseases, including pneumonia, meningitis and sepsis. S. pneumoniae is known to acquire methionine (Met) from its host through a Met importer. Here, the crystal structure of the substrate-binding protein (SBP; SP_0149) of an ABC importer with Met bound is reported at a resolution of 1.95 {\AA}. The three-dimensional structure of SBP shows that it is composed of two distinct domains, each consisting of a mixed $\beta$-sheet flanked by helices. The substrate, Met, is bound in the central part of the interface between the two domains. The overall structure of SP_0149 resembles those of SBPs from other reported bacterial Met and Gly-Met dipeptide transporters. However, a detailed analysis of these structures shows notable variations in the amino-acid composition of the substrate-binding pockets of the SP_0149-Met and GmpC-Gly-Met structures. In particular, SP_0149 harbors Thr212 and Tyr114, whereas the corresponding residues in GmpC are Gly and Val. This difference is likely to be the underlying basis for their differential substrate specificity. In summary, the structure of the SP_0149-Met complex provides insights into the transport function of SP_0149 and its interactions with methionine. It opens up avenues for the rational design of inhibitors of SP_0149 through a structure-mediated approach.

Acta Crystallographica Section F: Structural Biology Communications

Structural insights into the substrate specificity of SP_0149, the substrate-binding protein of a methionine ABC transporter from Streptococcus pneumoniae

Full control over the selectivity of carbon-carbon double-bond migrations would enable access to stereochemically defined olefins that are central to the pharmaceutical, food, fragrance, materials and petrochemical arenas. The vast majority of double-bond migrations investigated over the past 60 years capitalize on precious-metal hydrides that are frequently associated with reversible equilibria, hydrogen scrambling, incomplete E/Z stereoselection and/or high cost. Here, we report a fundamentally different, radical-based approach.We showcase a nonprecious, reductant-free and atom-economical nickel (Ni)(I)-catalyzed intramolecular 1,3-hydrogen atom relocation to yield E-olefins within 3 hours at room temperature. Remote installations of E-olefins over extended distances are also demonstrated.

Science

E-Olefins through intramolecular radical relocation

Tropical Calcific Pancreatitis (TCP) is a neglected juvenile form of chronic nonalcoholic pancreatitis. Cathepsin B (CTSB), a lysosomal protease involved in the cellular degradation process, has recently been studied as a potential candidate gene in the pathogenesis of TCP. According to the Cathepsin B hypothesis, mutated CTSB can lead to premature intracellular activation of trypsinogen, a key regulatory mechanism in pancreatitis. So far, CTSB mutations have been studied in pancreatitis and neurode-generative disorders, but little is known about the structural and functional effect of variants in CTSB. In this study, we investigated the effect of single nucleotide variants (SNVs) specifically associated with TCP, using molecular dynamics and simulation algorithms. There were two non-synonymous variants (L26V and S53G) of CTSB, located in the propeptide region. We tried to predict the effect of these variants on structure and function using multiple algorithms: SIFT, Polyphen2, PANTHER, SDM sever, i-Mutant2.0 suite, mCSM algorithm, and Vadar. Further, using databases like miRdbSNP, PolymiRTS, and miRNASNP, two SNPs in the 30UTR region were predicted to affect the miRNA binding sites. Structural mutated models of nsSNP mutants (L26V and S53G) were prepared by MODELLER v9.15 and evaluated using TM-Align, Verify 3D, ProSA and Ramachandran plot. The 3D mutated structures were simulated using GROMACS 5.0 to predict the impact of these SNPs on protein stability. The results from in silico analysis and molecular dynamics simulations suggested that these variants in the propeptide region of Cathepsin B could lead to structural and functional changes in the protein and thus could be pathogenic. Hence, the structural and functional analysis results have given interim conclusions that these variants can have a deleterious effect in TCP pathogenesis, either uniquely or in combination with other mutations. Thus, it could be extrapolated that Cathepsin B gene can be screened in samples from all TCP patients in future, to decipher the distribution of variants in patients. Copyright 2019 Singh et al.

PeerJ

Structural, functional and molecular dynamics analysis of cathepsin B gene SNPs associated with tropical calcific pancreatitis, a rare disease of tropics

In this work, we studied various properties of arithmetic function ˜ϕ, where ˜ϕ(n) = |{m ∈ N|1 ≤ m ≤ n, (m, n) = 1, m is not a prime}|. © Indian Mathematical Society, 2019.

Mathematics

Mathematics Student

Number of non-primes in the set of units modulon

Among 2-D nanostructures, graphene oxide is considered as the most attractive precursor nanomaterial for the utility of graphene in a variety of applications. There are problems associated with its mass production, which demands development of better and easier synthetic protocols. In addition, a chemical approach with a better control over degree of oxidation and nature of functionalities is simultaneously crucial for designing their structural modifications and the corresponding applications. Herein, three types of GOs are prepared by Hummers’, Intermediate and Improved method. A primary reaction step in GO synthesis is the formation of graphite intercalation compounds (GICs). The efficiency of oxidation and intercalant efficiency, non-oxidative Bronsted acid H 3 PO 4 /H 2 SO 4 and H 2 SO 4 are studied and properties are compared with the classical intercalant, H 2 SO 4 /NaNO 3 . A modulation in degree and nature of oxidative defects, flake size and stability of aqueous dispersion is observed, as supported by various analytical techniques. Depending upon the reaction conditions, the synthesized GOs revealed predominance of different type of oxidative functionalities and thereby reflected in associated physical properties, which is helpful to guide their usage for specific applications. © 2019 Elsevier B.V.