Development of an RNAi therapeutic for alpha-1-antitrypsin liver disease.

The autosomal codominant genetic disorder alpha-1 antitrypsin (AAT) deficiency (AATD) causes pulmonary and liver disease. Individuals homozygous for the mutant Z allele accumulate polymers of Z-AAT protein in hepatocytes, where AAT is primarily produced. This accumulation causes endoplasmic reticulum (ER) stress, oxidative stress, damage to mitochondria, and inflammation, leading to fibrosis, cirrhosis, and hepatocellular carcinoma.

Phosphorylation-specific status of RNAi triggers in pharmacokinetic and biodistribution analyses.

The RNA interference (RNAi)-based therapeutic ARC-520 for chronic hepatitis B virus (HBV) infection consists of a melittin-derived peptide conjugated to N-acetylgalactosamine for hepatocyte targeting and endosomal escape, and cholesterol-conjugated RNAi triggers, which together result in HBV gene silencing. To characterize the kinetics of RNAi trigger delivery and 5΄-phosphorylation of guide strands correlating with gene knockdown, we employed a peptide-nucleic acid (PNA) hybridization assay. A fluorescent sense strand PNA probe binding to RNAi duplex guide strands was coupled with anion exchange high performance liquid chromatography to quantitate guide strands and metabolites.

Ether modifications to 1-[2-(3,4-dimethoxyphenyl)ethyl]-4-(3-phenylpropyl)piperazine (SA4503): effects on binding affinity and selectivity for sigma receptors and monoamine transporters.

Two series of novel ether analogs of the sigma (σ) receptor ligand 1-[2-(3,4-dimethoxyphenyl)ethyl]-4-(3-phenylpropyl)piperazine (SA4503) have been prepared. In one series, the alkyl portion of the 4-methoxy group was replaced with allyl, propyl, bromoethyl, benzyl, phenethyl, and phenylpropyl moieties. In the second series, the 3,4-dimethoxy was replaced with cyclic methylenedioxy, ethylenedioxy and propylenedioxy groups.

Mechanisms of self-resistance in the platensimycin- and platencin-producing Streptomyces platensis MA7327 and MA7339 strains.

Platensimycin (PTM) and platencin (PTN) are potent inhibitors of bacterial fatty acid synthases and have emerged as promising antibacterial drug leads. We previously characterized the PTM and PTN biosynthetic machineries in the Streptomyces platensis producers. We now identify two mechanisms for PTM and PTN resistance in the S.

Biosynthetic potential-based strain prioritization for natural product discovery: a showcase for diterpenoid-producing actinomycetes.

Natural products remain the best sources of drugs and drug leads and serve as outstanding small-molecule probes to dissect fundamental biological processes. A great challenge for the natural product community is to discover novel natural products efficiently and cost effectively. Here we report the development of a practical method to survey biosynthetic potential in microorganisms, thereby identifying the most promising strains and prioritizing them for natural product discovery.

Hippocampal lesions in homing pigeons do not impair feature-quality or feature-quantity discrimination.

The role of the avian hippocampal formation (HF) in spatial cognition is well demonstrated. However, it remains uncertain if the avian hippocampus, like its mammalian counterpart, has a role in the integration of elements that could compose a memory independent of space. The two experiments in the current study examined whether the HF of homing pigeons (Columba livia) was required to encode into memory a discriminative representation of food quality (Experiment 1) and quantity (Experiment 2) with different food bowl-features.

Expression of the platencin biosynthetic gene cluster in heterologous hosts yielding new platencin congeners.

Platensimycin (PTM) and platencin (PTN) are potent and selective inhibitors of bacterial and mammalian fatty acid synthases and have emerged as promising drug leads for both antibacterial and antidiabetic therapies. We have previously cloned and sequenced the PTM-PTN dual biosynthetic gene cluster from Streptomyces platensis MA7327 and the PTN biosynthetic gene cluster from S. platensis MA7339, the latter of which is composed of 31 genes encoding PTN biosynthesis, regulation, and resistance.

Platensimycin and platencin biosynthesis in Streptomyces platensis, showcasing discovery and characterization of novel bacterial diterpene synthases.

Diterpenoid natural products cover a vast chemical diversity and include many medicinally and industrially relevant compounds. All diterpenoids derive from a common substrate, (E,E,E)-geranylgeranyl diphosphate, which is cyclized into one of many scaffolds by a diterpene synthase (DTS). While diterpene biosynthesis has been extensively studied in plants and fungi, bacteria are now recognized for their production of unique diterpenoids and are likely to harbor an underexplored reservoir of new DTSs.

Bacterial diterpene synthases: new opportunities for mechanistic enzymology and engineered biosynthesis.

Diterpenoid biosynthesis has been extensively studied in plants and fungi, yet cloning and engineering diterpenoid pathways in these organisms remain challenging. Bacteria are emerging as prolific producers of diterpenoid natural products, and bacterial diterpene synthases are poised to make significant contributions to our understanding of terpenoid biosynthesis. Here we will first survey diterpenoid natural products of bacterial origin and briefly review their biosynthesis with emphasis on diterpene synthases (DTSs) that channel geranylgeranyl diphosphate to various diterpenoid scaffolds.

Dedicated ent-kaurene and ent-atiserene synthases for platensimycin and platencin biosynthesis.

Platensimycin (PTM) and platencin (PTN) are potent and selective inhibitors of bacterial and mammalian fatty acid synthases and have emerged as promising drug leads for both antibacterial and antidiabetic therapies. Comparative analysis of the PTM and PTN biosynthetic machineries in Streptomyces platensis MA7327 and MA7339 revealed that the divergence of PTM and PTN biosynthesis is controlled by dedicated ent-kaurene and ent-atiserene synthases, the latter of which represents a new pathway for diterpenoid biosynthesis. The PTM and PTN biosynthetic machineries provide a rare glimpse at how secondary metabolic pathway evolution increases natural product structural diversity and support the wisdom of applying combinatorial biosynthesis methods for the generation of novel PTM and/or PTN analogues, thereby facilitating drug development efforts based on these privileged natural product scaffolds.

Septal area lesions impair spatial working memory in homing pigeons (Columba livia).

The septo-hippocampal system in birds resembles that of mammals, motivating research into the function of the avian hippocampus while surprisingly little attention has been given to the septum. To investigate a possible role of the avian septum in memory, the effects of septal area lesions on a spatial working memory (SpWM) task was tested in homing pigeons. After preoperative training on an analogue eight-arm (feeders) radial maze, now sham-operated control and septal lesioned pigeons were then trained again on the same task of locating the four feeders on the test phase of a trial that were not baited during the sample phase of a trial.

Engineering of Streptomyces platensis MA7339 for overproduction of platencin and congeners.

Platensimycin (1) and platencin (2) are novel antibiotic leads against multidrug resistant pathogens. The production of 2 in Streptomyces platensis MA7339 is under the control of ptnR1, a GntR-like transcriptional regulator. Inactivating ptnR1 afforded S.

Engineered Streptomyces platensis strains that overproduce antibiotics platensimycin and platencin.

Platensimycin, which is isolated from Streptomyces platensis MA7327, and platencin, which is isolated from S. platensis MA7339, are two recently discovered natural products that serve as important antibiotic leads. Here we report on the identification of S.