High potency improvements to weak aryl uracil HCV polymerase inhibitor leads.

Described herein is the development of a potent non-nucleoside, small molecule inhibitor of genotype 1 HCV NS5B Polymerase. A 23 µM inhibitor that was active against HCV polymerase was further elaborated into a potent single-digit nanomolar inhibitor of HCV NS5B polymerase by additional manipulation of the R and R1 substituents. Subsequent modifications to improve physical properties were made in an attempt to achieve an acceptable pharmacokinetic profile.

Testing the efficacy of culturally adapted coping skills training for Chinese American immigrants with type 2 diabetes using community-based participatory research.

Chinese Americans demonstrate greater prevalence of diabetes than non-Hispanic whites and find standard diabetes care disregards their cultural health beliefs. Academic researchers and Chinatown agencies collaborated to culturally adapt and test an efficacious cognitive-behavioral intervention using community-based participatory research. Using a delayed-treatment repeated-measures design, 145 adult Chinese immigrants with Type 2 diabetes completed treatment. Immediate benefits of treatment were evident in the improvement (p < .05) in diabetes self-efficacy, diabetes knowledge, bicultural efficacy, family emotional and instrumental support, diabetes quality of life, and diabetes distress. Prolonged benefits were evident in all changed variables 2 months post-intervention. The CBPR approach enabled the development of a culturally acceptable, efficacious behavioral intervention, and provides a model for working with communities that demonstrate health disparities.

The Hsp70 Ssz1 modulates the function of the ribosome-associated J-protein Zuo1.

J-proteins are obligate partners of Hsp70s, forming a ubiquitous class of molecular chaperone machinery. The ribosome-associated Hsp70 of yeast Ssb binds nascent polypeptides as they exit the ribosome. Here we report that the ribosome-associated J-protein Zuo1 is the partner of Ssb. However, Zuo1 efficiently stimulates the ATPase activity of Ssb only when in complex with another Hsp70, Ssz1. Ssz1 binds ATP, but none of the 11 different amino acid substitutions in the ATP-binding cleft affected Ssz1 function in vivo, suggesting that neither nucleotide binding nor hydrolysis is required. We propose that Ssz1's predominant function in the cell is to facilitate Zuo1's ability to function as a J-protein partner of Ssb on the ribosome, serving as an example of an Hsp70 family member that has evolved to carry out functions distinct from that of a chaperone.

Synthesis and evaluation of inhibitors of cytochrome P450 3A (CYP3A) for pharmacokinetic enhancement of drugs.

The HIV protease inhibitor ritonavir (RTV) is also a potent inhibitor of the metabolizing enzyme cytochrome P450 3A (CYP3A) and is clinically useful in HIV therapy in its ability to enhance human plasma levels of other HIV protease inhibitors (PIs). A novel series of CYP3A inhibitors was designed around the structural elements of RTV believed to be important to CYP3A inhibition, with general design features being the attachment of groups that mimic the P2-P3 segment of RTV to a soluble core. Several analogs were found to strongly enhance plasma levels of lopinavir (LPV), including 8, which compares favorably with RTV in the same model. Interestingly, an inverse correlation between in vitro inhibition of CYP3A and elevation of LPV was observed. The compounds described in this study may be useful for enhancing the pharmacokinetics of drugs that are metabolized by CYP3A.

Synthesis, antiviral activity, and conformational studies of a P3 aza-peptide analog of a potent macrocyclic tripeptide HCV protease inhibitor.

BILN 2061 is a macrocyclic tripeptide inhibitor of hepatitis C virus NS3-4A protease that has shown efficacy in the clinic for treating patients infected with HCV. We have synthesized a P3 aza-peptide analog of a potent macrocyclic tripeptide inhibitor closely related to BILN 2061. This aza-derivative was found to be >2 orders of magnitude less active than the parent macrocycle in both isolated enzyme (HCV NS3-4A) and HCV subgenomic replicon assays. NMR studies of P3 aza-peptides revealed these compounds adopt a beta-turn conformation stabilized by an intramolecular H-bonding interaction. Molecular models of these structures indicate a D-like configuration of the P3 aza-residue. Thus, the configurationally undefined nature at P3 in the aza-peptide allows the compound to adopt an H-bond stabilized conformation that is substantially different from that necessary for tight binding to the active site of HCV NS3 protease.

Cultural Adaptation of the Group Lifestyle Balance Program for Chinese Americans.

PURPOSE: The purpose of this pilot study was to develop and evaluate a culturally adapted, language-translated diabetes prevention program for Chinese Americans. METHODS: This pilot study had a single-group repeated-measures design. Participants were 25 first-generation (n = 20) or second-generation (n = 5) Chinese Americans at risk for diabetes because of overweight (using the Asian-specific criterion of body mass index ≥ 23) and either prediabetes or metabolic syndrome. The 16-session program was administered over 6 months in separate Mandarin (n = 9) and English (n = 16) groups. Outcomes were assessed at baseline and at 3 and 6 months. Four participants dropped out. Multilevel regression models were used to examine change in study outcomes over time. RESULTS: Participants lost an average of 5.4% of their body weight across the 6 months of the study. Self-report questionnaires suggested improved dietary intake and increased physical activity. Both total and low-density lipoprotein cholesterol levels improved. There were no statistically significant changes in fasting plasma glucose or A1C levels. Participants reported high satisfaction with and acceptance of the program. CONCLUSION: Results suggest that the culturally adapted Group Lifestyle Balance program for Chinese Americans was both acceptable and effective. The culturally adapted program warrants further examination using scientific approaches for dissemination and implementation.

Degradation of high affinity HuD targets releases Kv1.1 mRNA from miR-129 repression by mTORC1.

Little is known about how a neuron undergoes site-specific changes in intrinsic excitability during neuronal activity. We provide evidence for a novel mechanism for mTORC1 kinase-dependent translational regulation of the voltage-gated potassium channel Kv1.1 messenger RNA (mRNA). We identified a microRNA, miR-129, that repressed Kv1.1 mRNA translation when mTORC1 was active. When mTORC1 was inactive, we found that the RNA-binding protein, HuD, bound to Kv1.1 mRNA and promoted its translation. Unexpectedly, inhibition of mTORC1 activity did not alter levels of miR-129 and HuD to favor binding to Kv1.1 mRNA. However, reduced mTORC1 signaling caused the degradation of high affinity HuD target mRNAs, freeing HuD to bind Kv1.1 mRNA. Hence, mTORC1 activity regulation of mRNA stability and high affinity HuD-target mRNA degradation mediates the bidirectional expression of dendritic Kv1.1 ion channels.

Synthesis and biological characterization of B-ring amino analogues of potent benzothiadiazine hepatitis C virus polymerase inhibitors.

Benzothiadiazine inhibitors of the HCV NS5B RNA-dependent RNA polymerase are an important class of non-nucleoside inhibitors that have received considerable attention in the search for novel HCV therapeutics. Research in our laboratories has identified a novel series of tetracyclic benzothiadiazine inhibitors of HCV polymerase bearing a benzylamino substituent on the B-ring. Compounds in this series exhibit low-nanomolar activities in both genotypes 1a and 1b polymerase inhibition assays and subgenomic replicon assays. Optimization of pharmacokinetic properties in rat led to compound 30, which has good oral bioavailability (F = 56%) and a favorable tissue distribution drug profile, with high liver to plasma ratios. Compound 30 is a potent inhibitor in replicon assays, with EC(50) values of 10 and 6 nM against genotypes 1a and 1b, respectively.

Longer wavelength fluorescence resonance energy transfer depsipeptide substrates for hepatitis C virus NS3 protease.

Maturation of the hepatitis C virus (HCV) polyprotein occurs by a series of proteolytic processes catalyzed by host cell proteases and the virally encoded proteases NS2 and NS3. Although several peptidomimetic inhibitors of NS3 protease have been published, only a few small molecule inhibitors have been reported. In an effort to improve screening efficiency by minimizing the spectral interference of various test compounds, a substrate that contains the longer wavelength fluorescence resonance energy transfer (FRET) pair, TAMRA/QSY-7, was devised. For the optimized substrate T-Abu-Q, with sequence Ac-Asp-Glu-Lys(TAMRA)-Glu-Glu-Abu-Psi(COO)Ala-Ser-Lys(QSY-7)-amide, the kinetic parameters with HCV NS3 protease are K(m)=30 microM, k(cat)=0.6s(-1), and k(cat)/K(m)=20,100s(-1)M(-1). We show that this substrate is suitable for inhibitor analysis and mechanistic studies so long as the substrate concentration is low enough (0.5 microM) to avoid complications from high inner filter effects. The substrate is especially useful with ultra-high-density screening formats, such as microarrayed compound screening technology, because there is less spectral interference from the compounds being tested than with more traditional (EDANS/DABCYL) FRET protease substrates. The merits of the new substrate, as well as potential applications of this FRET pair to other protease substrates, are discussed.

Synthesis, antiviral activity, and pharmacokinetic evaluation of P3 pyridylmethyl analogs of oximinoarylsulfonyl HIV-1 protease inhibitors.

As a continuation of the recently communicated discovery of oximinoarylsulfonamides as potent inhibitors of HIV-1 aspartyl protease, compounds bearing pyridylmethyl substituents at P3 were designed and synthesized. Potent analogs in this series provided low single-digit nanomolar EC50 values against both wild-type HIV and resistant mutant virus (A17), attenuated some 3- to 12-fold in the presence of 50% human serum. Pharmacokinetic results for compounds in this series showed good to excellent exposure when co-administered orally with an equal amount of ritonavir (5mg/kg each) in the rat, with average AUC >8 microg h/mL. Similar dosing in dog resulted in significantly lower plasma levels (average AUC <2 microg h/mL). The 3-pyridylmethyl analog 30 gave the best overall exposure (rat AUC=7.1 microg h/mL and dog AUC=4.9 microg h/mL), however, this compound was found to be a potent inhibitor of cytochrome P450 3A (Ki=2.4 nM).

Synthesis and antiviral activity of P1' arylsulfonamide azacyclic urea HIV protease inhibitors.

A series of novel azacyclic urea HIV protease inhibitors bearing a benzenesulfonamide group at P1' were synthesized utilizing a parallel synthesis method. Structural studies of early analogs bound in the enzyme active site were used to design more potent inhibitors. The effects of substituting the P1' benzenesulfonyl group on antiviral activity and protein binding are described.

Mutations conferring resistance to a potent hepatitis C virus serine protease inhibitor in vitro.

BILN 2061 is a novel, specific hepatitis C virus (HCV) NS3 serine protease inhibitor discovered by Boehringer Ingelheim that has shown potent activity against HCV replicons in tissue culture and is currently under clinical investigation for the treatment of HCV infection. The poor fidelity of the HCV RNA-dependent RNA polymerase will likely lead to the development of drug-resistant viruses in treated patients. The development of resistance to BILN 2061 was studied by the in vitro passage of HCV genotype 1b replicon cells in the presence of a fixed concentration of the drug. Three weeks posttreatment, four colonies were expanded for genotypic and phenotypic characterization. The 50% inhibitory concentrations of BILN 2061 for these colonies were 72- to 1,228-fold higher than that for the wild-type replicon. Sequencing of the individual colonies identified several mutations in the NS3 serine protease gene. Molecular clones containing the single amino acid substitution A156T, R155Q, or D168V resulted in 357-fold, 24-fold, and 144-fold reductions in susceptibility to BILN 2061, respectively, compared to the level of susceptibility shown by the wild-type replicon. Modeling studies indicate that all three of these residues are located in close proximity to the inhibitor binding site. These findings, in addition to the three-dimensional structure analysis of the NS3/NS4A serine protease inhibitor complex, provide a strategic guide for the development of next-generation inhibitors of HCV NS3/NS4A serine protease.