Development and characterization of synthetic antibodies binding to the cystic fibrosis conductance regulator

Cystic fibrosis transmembrane conductance regulator (CFTR) is a chloride channel in the apical surface of epithelial cells in the airway and gastrointestinal tract, and mutation of CFTR is the underlying cause of cystic fibrosis. However, the precise molecular details of the structure and function of CFTR in native and disease states remains elusive and cystic fibrosis researchers are hindered by a lack of high specificity, high affinity binding reagents for use in structural and biological studies. Here, we describe a panel of synthetic antigen-binding fragments (Fabs) isolated from a phage-displayed library that are specific for intracellular domains of CFTR that include the nucleotide-binding domains (NBD1 and NBD2), the R-region, and the regulatory insertion loop of NBD1. Binding assays performed under conditions that promote the native fold of the protein demonstrated that all Fabs recognized full-length CFTR. However, only the NBD1-specific Fab recognized denatured CFTR by western blot, suggesting a conformational epitope requirement for the other Fabs. Surface plasmon resonance experiments showed that the R-region Fab binds with high affinity to both the phosphorylated and unphosphorylated R-region. In addition, NMR analysis of bound versus unbound R-region revealed a distinct conformational effect upon Fab binding. We further defined residues involved with antibody recognition using an overlapping peptide array. In summary, we describe methodology complementary to previous hybridoma-based efforts to develop antibody reagents to CFTR, and introduce a synthetic antibody panel to aid structural and biological studies

Lamotrigine versus inert placebo in the treatment of borderline personality disorder: study protocol for a randomized controlled trial and economic evaluation

Background: People with borderline personality disorder (BPD) experience rapid and distressing changes in mood, poor social functioning and have high rates of suicidal behaviour. Several small scale studies suggest that mood stabilizers may produce short-term reductions in symptoms of BPD, but have not been large enough to fully examine clinical and cost-effectiveness. Methods/Design: A two parallel-arm, placebo controlled randomized trial of usual care plus either lamotrigine or an inert placebo for people aged over 18 who are using mental health services and meet diagnostic criteria for BPD. We will exclude people with comorbid bipolar affective disorder or psychosis, those already taking a mood stabilizer, those who speak insufficient English to complete the baseline assessment and women who are pregnant or contemplating becoming pregnant. Those meeting inclusion criteria and provide written informed consent will be randomized to up to 200mg of lamotrigine per day or an inert placebo (up to 400mg if taking combined oral contraceptives).Participants will be randomized via a remote web-based system using permuted stacked blocks stratified by study centre, severity of personality disorder, and level of bipolarity. Follow-up assessments will be conducted by masked researchers 12, 24 weeks, and 52 weeks after randomization. The primary outcome is the Zanarini Rating Scale for Borderline Personality Disorder (ZAN-BPD). The secondary outcomes are depressive symptoms, deliberate self-harm, social functioning, health-related quality of life, resource use and costs, side effects of treatment, adverse events and withdrawal of trial medication due to adverse effects. The main analyses will use intention to treat without imputation of missing data. The economic evaluation will take an NHS/Personal Social Services perspective. A cost-utility analysis will compare differences in total costs and differences in quality of life using QALYs derived from the EQ-5D. Discussion: The evidence base for the use of pharmacological treatments for people with borderline personality disorder is poor. In this trial we will examine the clinical and cost-effectiveness of lamotrigine to assess what if any impact offering this has on peoples’ mental health, social functioning, and use of other medication and other resources. Trial registration: Current Controlled Trials ISRCTN90916365 (registered 01/08/2012

Development and characterization of synthetic antibodies binding to the cystic fibrosis conductance regulator

Cystic fibrosis transmembrane conductance regulator (CFTR) is a chloride channel in the apical surface of epithelial cells in the airway and gastrointestinal tract, and mutation of CFTR is the underlying cause of cystic fibrosis. However, the precise molecular details of the structure and function of CFTR in native and disease states remains elusive and cystic fibrosis researchers are hindered by a lack of high specificity, high affinity binding reagents for use in structural and biological studies. Here, we describe a panel of synthetic antigen-binding fragments (Fabs) isolated from a phage-displayed library that are specific for intracellular domains of CFTR that include the nucleotide-binding domains (NBD1 and NBD2), the R-region, and the regulatory insertion loop of NBD1. Binding assays performed under conditions that promote the native fold of the protein demonstrated that all Fabs recognized full-length CFTR. However, only the NBD1-specific Fab recognized denatured CFTR by western blot, suggesting a conformational epitope requirement for the other Fabs. Surface plasmon resonance experiments showed that the R-region Fab binds with high affinity to both the phosphorylated and unphosphorylated R-region. In addition, NMR analysis of bound versus unbound R-region revealed a distinct conformational effect upon Fab binding. We further defined residues involved with antibody recognition using an overlapping peptide array. In summary, we describe methodology complementary to previous hybridoma-based efforts to develop antibody reagents to CFTR, and introduce a synthetic antibody panel to aid structural and biological studies

A synthetic anti-Frizzled antibody engineered for broadened specificity exhibits enhanced anti-tumor properties

Secreted Wnt ligands play a major role in the development and progression of many cancers by modulating signaling through cell-surface Frizzled receptors (FZDs). In order to achieve maximal effect on Wnt signaling by targeting the cell surface, we developed a synthetic antibody targeting six of the 10 human FZDs. We first identified an anti-FZD antagonist antibody (F2) with a specificity profile matching that of OMP-18R5, a monoclonal antibody that inhibits growth of many cancers by targeting FZD7, FZD1, FZD2, FZD5 and FZD8. We then used combinatorial antibody engineering by phage display to develop a variant antibody F2.A with specificity broadened to include FZD4. We confirmed that F2.A blocked binding of Wnt ligands, but not binding of Norrin, a ligand that also activates FZD4. Importantly, F2.A proved to be much more efficacious than either OMP-18R5 or F2 in inhibiting the growth of multiple RNF43-mutant pancreatic ductal adenocarcinoma cell lines, including patient-derived cells