Preserving Vascular Integrity Protects Mice against Multidrug-Resistant Gram-Negative Bacterial Infection.

The rise in multidrug-resistant (MDR) organisms portends a serious global threat to the health care system with nearly untreatable infectious diseases, including pneumonia and its often fatal sequelae, acute respiratory distress syndrome (ARDS) and sepsis. Gram-negative bacteria (GNB), including , , and carbapenemase-producing (CPKP), are among the World Health Organization's and National Institutes of Health's high-priority MDR pathogens for targeted development of new therapies. Here, we show that stabilizing the host's vasculature by genetic deletion or pharmacological inhibition of the small GTPase ADP-ribosylation factor 6 (ARF6) increases survival rates of mice infected with , , and CPKP.

ARF6 Is an Actionable Node that Orchestrates Oncogenic GNAQ Signaling in Uveal Melanoma.

Activating mutations in Gαq proteins, which form the α subunit of certain heterotrimeric G proteins, drive uveal melanoma oncogenesis by triggering multiple downstream signaling pathways, including PLC/PKC, Rho/Rac, and YAP. Here we show that the small GTPase ARF6 acts as a proximal node of oncogenic Gαq signaling to induce all of these downstream pathways as well as β-catenin signaling. ARF6 activates these diverse pathways through a common mechanism: the trafficking of GNAQ and β-catenin from the plasma membrane to cytoplasmic vesicles and the nucleus, respectively.

Discovery of an L-alanine ester prodrug of the Hsp90 inhibitor, MPC-3100.

Various types of Hsp90 inhibitors have been and continue to undergo clinical investigation. One development candidate is the purine-based, synthetic Hsp90 inhibitor 1 (MPC-3100), which successfully completed a phase I clinical study. However, further clinical development of 1 was hindered by poor solubility and consequent formulation issues and promoted development of a more water soluble prodrug.

Discovery of a new HIV-1 inhibitor scaffold and synthesis of potential prodrugs of indazoles.

A new oxazole scaffold showing great promise in HIV-1 inhibition has been discovered by cell-based screening of an in-house library and scaffold modification. Follow-up SAR study focusing on the 5-aryl substituent of the oxazole core has identified 4k (EC50=0.42μM, TI=50) as a potent inhibitor.

Discovery of (2S)-1-[4-(2-{6-amino-8-[(6-bromo-1,3-benzodioxol-5-yl)sulfanyl]-9H-purin-9-yl}ethyl)piperidin-1-yl]-2-hydroxypropan-1-one (MPC-3100), a purine-based Hsp90 inhibitor.

Modulation of Hsp90 (heat shock protein 90) function has been recognized as an attractive approach for cancer treatment, since many cancer cells depend on Hsp90 to maintain cellular homeostasis. This has spurred the search for small-molecule Hsp90 inhibitors. Here we describe our lead optimization studies centered on the purine-based Hsp90 inhibitor 28a containing a piperidine moiety at the purine N9 position.

Structural effects of hypermodified nucleosides in the Escherichia coli and human tRNALys anticodon loop: the effect of nucleosides s2U, mcm5U, mcm5s2U, mnm5s2U, t6A, and ms2t6A.

Previous nuclear magnetic resonance (NMR) studies of unmodified and pseudouridine39-modified tRNA(Lys) anticodon stem loops (ASLs) show that significant structural rearrangements must occur to attain a canonical anticodon loop conformation. The Escherichia coli tRNA(Lys) modifications mnm(5)s(2)U34 and t(6)A37 have indeed been shown to remodel the anticodon loop, although significant dynamic flexibility remains within the weakly stacked U35 and U36 anticodon residues. The present study examines the individual effects of mnm(5)s(2)U34, s(2)U34, t(6)A37, and Mg(2+) on tRNA(Lys) ASLs to decipher how the E.

Introduction of hypermodified nucleotides in RNA.

The anticodon domain of lysine transfer ribonucleic acid (tRNA) is a model system for investigation of the structural and biochemical effects of nucleoside posttranscriptional modification. To enable detailed study of the biophysical and structural effects of hypermodified nucleosides, methods have been developed to synthesize RNA oligonucleotides containing the modified nucleosides found in lysine tRNA. We describe in detail the synthesis of protected phosphoramidites of the nucleosides methylaminomethyl-2-thiouridine (mnm5s2U), methylcarboxymethyl-2-thiouridine (mcm5s2U), and 2-thiomethyl-N-6-carbamoylthreonyl-adenosine (ms2t6A).

An RNA complex of the HIV-1 A-loop and tRNA(Lys,3) is stabilized by nucleoside modifications.

The HIV transcription initiation complex involves a putative interaction between the primer tRNA anticodon and a conserved A-rich loop in the HIV genome. Surface plasmon resonance was used to demonstrate that the hypermodified nucleosides in the tRNA anticodon stem loop (ASL) stabilize RNA-RNA interactions in a model for the anticodon/A-loop complex. tRNA ASL hairpins with the modifications of Escherchia coli tRNALys and human tRNALys,3 each form stable complexes.

Synthesis of the tRNA(Lys,3) anticodon stem-loop domain containing the hypermodified ms2t6A nucleoside.

The synthesis of a protected form of the hypermodified nucleoside, N-[(9-beta-D-ribofuranosyl-2-methylthiopurin-6-yl)carbamoyl]threonine, (ms2t6A) is reported. The hypermodified nucleoside was subsequently elaborated to the protected nucleoside phosphophoramidite using a protecting group strategy compatible with standard RNA oligonucleotide chemistry. The phosphoramidite reagent was then used to synthesize the 17-nucleotide RNA hairpin having the sequence of the anticodon stem-loop (ASL) domain of human tRNA(Lys,3), the primer for HIV-1 reverse transcriptase.

Structural features of tRNALys favored by anticodon nuclease as inferred from reactivities of anticodon stem and loop substrate analogs.

The bacterial tRNA(Lys)-specific PrrC-anticodon nuclease efficiently cleaved an anticodon stem-loop (ASL) oligoribonucleotide containing the natural modified bases, suggesting this region harbors the specificity determinants. Assays of ASL analogs indicated that the 6-threonylcarbamoyl adenosine modification (t(6)A37) enhances the reactivity. The side chain of the modified wobble base 5-methylaminomethyl-2-thiouridine (mnm(5)s(2)U34) has a weaker positive effect depending on the context of other modifications.

(-)3-[4-[2-(Phenoxazin-10-yl)ethoxy]phenyl]-2-ethoxypropanoic acid [(-)DRF 2725]: a dual PPAR agonist with potent antihyperglycemic and lipid modulating activity.

(-)DRF 2725 (6) is a phenoxazine analogue of phenyl propanoic acid. Compound 6 showed interesting dual activation of PPAR alpha and PPAR gamma. In insulin resistant db/db mice, 6 showed better reduction of plasma glucose and triglyceride levels as compared to rosiglitazone.

Synthesis and biophysical characterization of tRNA(Lys,3) anticodon stem-loop RNAs containing the mcm(5)s(2)U nucleoside.

[reaction: see text] Phosphoramidite reagents of the naturally occurring modified nucleosides mcm(5)s(2)U and mcm(5)U were synthesized and along with pseudouridine were incorporated into 17-nucleotide lysine tRNA anticodon stem-loop domains. Standard RNA phosphoramidite coupling chemistry allowed us to systematically investigate the thermodynamic effects of nucleoside modification and to correlate thermodynamic trends with qualitative structure effects seen by NMR spectroscopy.

Novel antidiabetic and hypolipidemic agents. 3. Benzofuran-containing thiazolidinediones.

Several thiazolidinedione derivatives having 5-hydroxy-2,3-dihydro-2, 2,4,6,7-pentamethylbenzofuran moieties and their 5-benzyloxy derivatives and 5-hydroxy-2,4,6,7-tetramethylbenzofuran moieties were synthesized and evaluated in db/db mice. Insertion of an N-Me group into the linker between thiazolidinedione and substituted benzofuran pharmacophores showed considerable improvement in their euglycemic activity. Further improvement has been observed when a pyrrolidine moiety is introduced in the structure to give 5-[4-[N-[3(R/S)-5-benzyloxy-2,3-dihydro-2,2,4,6, 7-pentamethylbenzofuran-3-ylmethyl]-(2S)-pyrrolidin-2- ylmethoxy]pheny lene]thiazolidine-2,4-dione (21a).

Novel euglycemic and hypolipidemic agents: Part-2. Antioxidant moiety as structural motif.

Several thiazolidinediones having antioxidant moities in their structural motif have been synthesised and evaluated for their euglycemic and hypolipidemic activities. A few of them have been found to be superior to troglitazone.

Possible antifertility agents belonging to substituted indoles.

Of the 21 compounds evaluated for antiimplantation and abortifacient activities, compounds (A1, A2, A4 and B1) and compounds (C1, C2, D1 and D3) were found to exhibit 40% and 30% antiimplantation activity, respectively, in female rats when given orally on days 1-5 postcoitum. The remaining 13 compounds were found to be inactive. All of the 21 compounds were also tested for the abortifacient activity, but all were found to be inactive.