Publications by authors named "Justin K Murray"

Background: Human genetic studies have identified several mitochondrial amidoxime-reducing component 1 (MTARC1) variants as protective against metabolic dysfunction-associated steatotic liver disease. The MTARC1 variants are associated with decreased plasma lipids and liver enzymes and reduced liver-related mortality. However, the role of mARC1 in fatty liver disease is still unclear.

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N-acetylgalactosamine (GalNAc)-modified small interfering ribonucleic acids (siRNA) have shown promising outcomes for targeted siRNA delivery resulting in gene silencing in vivo; however, their structural complexity requires development of new purification methods to address high purity and recovery requirements. The current study evaluates complementary purification approaches using a mixed-mode Scherzo SS-C18 and anion-exchange (AEX) TSK-gel SuperQ-5PW for a range of single-stranded triantennary GalNAc-oligonucleotides. Initially, the semi-preparative mixed-mode support (10 × 250 mm, 3 µm) was compared against the preparative AEX analogue (21.

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Human genome wide association studies confirm the association of the rs738409 single nucleotide polymorphism (SNP) in the gene encoding protein patatin like phospholipase domain containing 3 () with nonalcoholic fatty liver disease (NAFLD); the presence of the resulting mutant PNPLA3 I148M protein is a driver of nonalcoholic steatohepatitis (NASH). While -deficient mice do not display an adverse phenotype, the safety of knocking down endogenous wild type in humans remains unknown. To expand the scope of a potential targeted NAFLD therapeutic to both homozygous and heterozygous rs738409 populations, we sought to identify a minor allele-specific small interfering RNA (siRNA).

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The current study investigates a method for purification of the G-quadruplex secondary structure, naturally formed by a guanine-rich 21-mer oligonucleotide strand using a monolithic convective interaction media-quaternary amine (CIM-QA) column under ion-exchange conditions. The monolithic support was initially evaluated on a preparative scale against a highly efficient TSKgel SuperQ-5PW ion-exchange support designed for oligonucleotide purification. The CIM analogue demonstrated clear advantages over the particle-based support on the basis of rapid separation times, while also affording high purity of the G-quadruplex.

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Drug discovery research on new pain targets with human genetic validation, including the voltage-gated sodium channel Na1.7, is being pursued to address the unmet medical need with respect to chronic pain and the rising opioid epidemic. As part of early research efforts on this front, we have previously developed Na1.

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Inhibitors of the voltage-gated sodium channel Na1.7 are being investigated as pain therapeutics due to compelling human genetics. We previously identified Na1.

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Identification of voltage-gated sodium channel NaV1.7 inhibitors for chronic pain therapeutic development is an area of vigorous pursuit. In an effort to identify more potent leads compared to our previously reported GpTx-1 peptide series, electrophysiology screening of fractionated tarantula venom discovered the NaV1.

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The voltage-gated sodium channel Na1.7 is a genetically validated pain target under investigation for the development of analgesics. A therapeutic with a less frequent dosing regimen would be of value for treating chronic pain; however functional Na1.

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There is interest in the identification and optimization of new molecular entities selectively targeting ion channels of therapeutic relevance. Peptide toxins represent a rich source of pharmacology for ion channels, and we recently reported GpTx-1 analogs that inhibit NaV1.7, a voltage-gated sodium ion channel that is a compelling target for improved treatment of pain.

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To realize the medicinal potential of peptide toxins, naturally occurring disulfide-rich peptides, as ion channel antagonists, more efficient pharmaceutical optimization technologies must be developed. Here, we show that the therapeutic properties of multiple cysteine toxin peptides can be rapidly and substantially improved by combining direct chemical strategies with high-throughput electrophysiology. We applied whole-molecule, brute-force, structure-activity analoging to ShK, a peptide toxin from the sea anemone Stichodactyla helianthus that inhibits the voltage-gated potassium ion channel Kv1.

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Many efforts are underway to develop selective inhibitors of the voltage-gated sodium channel NaV1.7 as new analgesics. Thus far, however, in vitro selectivity has proved difficult for small molecules, and peptides generally lack appropriate pharmacokinetic properties.

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NaV1.7 is a voltage-gated sodium ion channel implicated by human genetic evidence as a therapeutic target for the treatment of pain. Screening fractionated venom from the tarantula Grammostola porteri led to the identification of a 34-residue peptide, termed GpTx-1, with potent activity on NaV1.

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The determination of the disulfide bond connectivity in a peptide or protein represents a significant challenge. It is notoriously difficult to use NMR spectroscopy to assign disulfide connectivities because NMR spectra lack direct evidence for disulfide bonds. These bonds are typically inferred from three-dimensional structure calculations, which can result in ambiguous disulfide assignment.

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Since the advent of solid-phase peptide synthesis (SPPS) in the late 1950s, numerous advancements in the underlying chemistry (i.e., orthogonal protection strategy, coupling reagents, and solid support matrices) have greatly improved the efficiency of the technique.

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Intracellular levels of the hypoxia-inducible transcription factor (HIF) are regulated under normoxic conditions by prolyl hydroxylases (PHD1, 2, and 3). Treatment of cells with PHD inhibitors stabilizes HIF-1α, eliciting an artificial hypoxic response that includes the transcription of genes involved in erythropoiesis, angiogenesis, and glycolysis. The different in vivo roles of the three PHD isoforms are not yet known, making a PHD-selective inhibitor useful as a biological tool.

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We describe the use of parallel and split-and-mix library synthesis strategies for exploration of structure-activity relationships among peptidic foldamer ligands for the BH3-recognition cleft of the anti-apoptotic protein Bcl-xL. This effort began with a chimeric (alpha/beta+alpha)-peptide oligomer (composed of an alpha/beta-peptide segment and an alpha-peptide segment) that we previously identified to bind tightly to the target cleft on Bcl-xL. The side chains that interact with Bcl-xL were varied in a 1000-member one-bead-one-compound library.

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Protein-protein interactions play crucial roles in cell-signaling events and are often implicated in human disease. Molecules that bind tightly to functional protein-surface sites and show high stability to degradative enzymes could be valuable pharmacological tools for dissection of cell-signaling networks and might ultimately lead to therapeutic agents. We recently described oligomers containing both alpha- and beta-amino acid residues that bind tightly to the BH3 recognition site of the anti-apoptotic protein Bcl-x(L).

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The tremendous challenge of inhibiting therapeutically important protein-protein interactions has created the opportunity to extend traditional medicinal chemistry to a new class of targets and to explore nontraditional strategies. Here we review a widely studied system, the interaction between tumor suppressor p53 and its natural antagonist MDM2, for which both traditional and nontraditional approaches have been reported. This system has been a testing ground for novel proteomimetic scaffold-based strategies, i.

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The application of microwave irradiation to solid-phase peptide synthesis increases product purity and reduces reaction time. Parallel synthesis in 96-well polypropylene filter plates with microwave irradiation is an efficient method for the rapid generation of combinatorial peptide libraries in sufficient purity to assay the products directly for biological activity without HPLC purification. In this protocol, the solid-phase support is arrayed into each well of a 96-well plate, reagents are delivered using a multichannel pipette and a microwave reactor is used to complete peptide coupling reactions in 6 min and Fmoc-removal reactions in 4 min under temperature-controlled conditions.

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Establishment of angiogenic circuits that orchestrate blood vessel development and remodeling requires an exquisite balance between the activities of pro- and antiangiogenic factors. However, the logic that permits complex signal integration by vascular endothelium is poorly understood. We demonstrate that a "neuropeptide," neurokinin-B (NK-B), reversibly inhibits endothelial cell vascular network assembly and opposes angiogenesis in the chicken chorioallantoic membrane.

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To facilitate the preparation of beta-peptide libraries in parallel, we have adapted reaction conditions for the solid-phase synthesis of 14-helical beta-peptides for use in a multimode microwave reactor. The low temperature/pressure requirements of microwave-assisted beta-peptide synthesis were found to be compatible with multiwell filter plates composed of polypropylene. Microwave heating of the 96-well plate was sufficiently homogeneous to allow the rapid preparation of a beta-peptide library in acceptable purity.

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The predictable relationship between beta-amino acid sequence and folding has inspired several biological applications of beta-peptides. For many such applications, it would be desirable to prepare and screen beta-peptide libraries. However, standard peptide synthesis protocols are not efficient enough to support a library approach for many types of beta-peptides.

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[structure: see text] We have evaluated the effects of microwave irradiation on the solid-phase synthesis of beta-peptides. Sequences designed to adopt the 14-helix, especially those containing the structure-promoting residue trans-2-aminocyclohexanecarboxylic acid (ACHC), suffer from poor synthetic efficiency under standard SPPS conditions. A comparison of microwave and conventional heating shows that both provide excellent synthetic results for shorter sequences; however, we identify a clear benefit from microwave irradiation for longer beta-peptides.

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