Synthesis and in vitro Biological Evaluation of Novel Thymidine Analogs Containing 1H-1,2,3-Triazolyl, 1H-Tetrazolyl,and 2H-Tetrazolyl Fragments

Abstract

3′-Azidothymidine (AZT) reacts with 1-propargyl-5-R-1H- and 2-propargyl-5-R-2H-tetrazoles (R?=?H, Me, CH₂COOEt, CH₂CON(CH₃)₂, Ph, 2-CH₃-C₆H₄, or 4-NO₂-C₆H₄) via the Cu(I)-catalyzed asymmetric [3?+?2] cycloaddition to give 3′-modified thymidine analogs incorporating 1H-1,2,3-triazolyl, 1H-, and 2H-tetrazolyl fragments in 41–76% yield. The structures of the obtained compounds have been elucidated by means of HRESI⁺-MS, ¹H and ¹³ Ostrovskii, V. A.; Popova, E. A.; Trifonov, R. E. Developments in Tetrazole Chemistry (2009–16). Advances in heterocyclic chemistry. 2017, 123, 2–62.[Web of Science ®] , [Google Scholar]C{¹H} NMR, and single crystal X-ray diffraction {for 3′-[4-(1H-5-N,N-dimethylaminocarbonylmethyltetrazol-1-yl)-1H-1,2,3-triazol-1-yl]thymidine 10d}. In vitro biological evaluation of the prepared compounds has been performed; they have exhibited low activity against phenotypic HIV-1_899A. Moderate anti-influenza activity against influenza virus A/Puerto Rico/8/34 (H1N1) strain has been observed in the cases of 3′-(4-(1H-tetrazol-1-ylmethyl)-1H-1,2,3-triazol-1-yl)thymidine 10a (IC₅₀ 39.6?μg/mL), 3′-(4-(2H-5-ethoxycarbonyltetrazol-2-ylmethyl)-1H-1,2,3-triazol-1-yl)thymidine 11c (IC₅₀ 31.6?μg/mL), and 3′-(4-(2H-5-(4-nitrophenyl)-tetrazol-2-ylmethyl)-1H-1,2,3-triazol-1-yl)thymidine 11g (IC₅₀ 46.4?μg/mL). The tested compounds possess very low cytotoxicity towards MDCK and MT4 cells as well as tumor human cervical carcinoma HeLa and promyelocytic leukemia HL-60 cells.     

Elevated systemic antibodies towards commensal gut microbiota in autoinflammatory condition

Background

Familial Mediterranean fever (FMF) is an autoinflammatory condition, which is characterized by acute, self-limiting episodes of fever and serositis and chronic subclinical inflammation in remission. Here we investigated the consequence of this condition on the level of systemic antibodies directed towards common intestinal bacteria.

Methodology/Principal Findings

The level of systemic antibodies towards the antigens of Bacteroides, Parabacteroides, Escherichia, Enteroccocus and Lactobaccilus was measured by ELISA in FMF patients at various stages of the disease and in healthy controls. The difference between remission and attack was not significant. IgG antibodies against the antigens of Bacteroides, Parabacteroides, Escherichia and Enteroccocus were significantly increased in FMF compared to control while IgA levels were not significantly affected. Western blot analyses demonstrated the IgG reactivity against multiple antigens of commensal bacteria in FMF. Serological expression cloning was performed to identify these antigens. No single dominant antigen was identified; the response was generalized and directed against a variety of proteins from Bacteroides, Parabacteroides, Escherichia, and other gut commensals.

Conclusions/Significance

This autoinflammatory syndrome is characterized by the increased systemic reactivity against commensal gut microbiota. This is probably the consequence of hypersensitivity of the inflammasome in FMF that triggers the inflammation and contributes to the excessive translocation of bacteria and bacterial antigens through the gut barrier.     

Acquisition of blood--tissue barrier--supporting features by hepatic stellate cells and astrocytes of myofibroblastic phenotype. Inverse dynamics of metallothionein and glial fibrillary acidic protein expression

A number of similarities between astrocytes and hepatic stellate cells (HSC) rose the question whether or not the protective barrier features of blood-tissue interface may be provided by HSC as well. To test this hypothesis, we investigated the presence of metallothionein (MT), a functional marker of blood--brain barrier, in HSC in situ and in cell culture and compared the results with those obtained with astrocytes. The dynamics of MT expression in cultured astrocytes and HSC was investigated by simultaneous labelling of the cells with a monoclonal antibody (MAb MT) against a lysine-containing epitope of the cadmium-induced monomer of MT-I from rat liver and antiserum against glial fibrillary acidic protein (GFAP). Cell activation was estimated by the presence of smooth muscle alpha-actin (SMAA). In immunoblotting, MAb MT recognized monomeric MT protein and proteins in the 30-kDa range; both bands were pronounced in brain and barely visible in liver homogenates. In situ, MAb MT reacted with very few perivascular cells situated in the parenchyma of the liver. Double immunolabelling of brain slices with MAb MT and antiserum against GFAP showed large areas of brain containing cells expressing both MT and GFAP. However, there were also regions in the brain where the cells produced solely GFAP or MT. In liver cell culture, MT was absent from HSC and hepatocytes in early periods of cultivation, during which the cells maintained their original features; however, MT was expressed strongly in HSC during their activation under prolonged culture conditions. Inversely, in astrocytes MT was expressed during early culturing and disappeared from the cells together with SMAA in late culture when GFAP was upregulated. These results suggest that the acquisition of myofibroblastic features by perivascular cells empowers them to establish a protective blood-tissue permeability barrier. In addition, this study shows that, at least in cell culture, an enrichment of perivascular cells in GFAP results in the disappearance of protective functions.     

Vacuolization of target cells: response to microbial toxins

Summary Vacuolization as a marker of microbial activity on cells is a well-known reaction. The phenomenon involves the formation of vacuoles in the cytoplasm of target cells followed by lysis, especially after the action of different cytotoxins. In this review we summarize data on microbial toxic products causing vacuolization of target cells in the light of recent publications, on the basis of the widely described VacA cytotoxin of Helicobacter pylori.     

Neuroligins determine synapse maturation and function

Synaptogenesis, the generation and maturation of functional synapses between nerve cells, is an essential step in the development of neuronal networks in the brain. It is thought to be triggered by members of the neuroligin family of postsynaptic cell adhesion proteins, which may form transsynaptic contacts with presynaptic alpha- and beta-neurexins and have been implicated in the etiology of autism. We show that deletion mutant mice lacking neuroligin expression die shortly after birth due to respiratory failure. This respiratory failure is a consequence of reduced GABAergic/glycinergic and glutamatergic synaptic transmission and network activity in brainstem centers that control respiration. However, the density of synaptic contacts is not altered in neuroligin-deficient brains and cultured neurons. Our data show that neuroligins are required for proper synapse maturation and brain function, but not for the initial formation of synaptic contacts.     

Haploinsufficiency of c-Met in cd44-/- mice identifies a collaboration of CD44 and c-Met in vivo

Recent evidence has shown that the activation of receptor tyrosine kinases is not only dependent on binding of their ligands but in addition requires adhesion molecules as coreceptors. We have identified CD44v6 as a coreceptor for c-Met in several tumor and primary cells. The CD44v6 ectodomain is required for c-Met activation, whereas the cytoplasmic tail recruits ERM proteins and the cytoskeleton into a signalosome complex. Here we demonstrate that c-Met (and hepatocyte growth factor and Gab1) is haploinsufficient in a cd44^−/− background, as the cd44^−/−; met^+/− (and cd44^−/−; hgf^+/− and cd44^−/−; gab1^+/−) mice die at birth. They have impaired synaptic transmission in the respiratory rhythm-generating network and alterations in the phrenic nerve. These results are the first genetic data showing that CD44 and c-Met collaborate in vivo and that they are involved in synaptogenesis and axon myelination in the central and peripheral nervous systems.