Imaging of adeno-associated viral capsids for purposes of gene editing using CEST NMR/MRI.

PURPOSE: Gene therapy using adeno-associated virus (AAV) vector-mediated gene delivery has undergone substantial growth in recent years with promising results in both preclinical and clinical studies, as well as emerging regulatory approval. However, the inability to quantify the efficacy of gene therapy from cellular delivery of gene-editing technology to specific functional outcomes is an obstacle for efficient development of gene therapy treatments. Building on prior works that used the CEST reporter gene lysine rich protein, we hypothesized that AAV viral capsids may generate endogenous CEST contrast from an abundance of surface lysine residues. METHODS: NMR experiments were performed on isolated solutions of AAV serotypes 1-9 on a Bruker 800-MHz vertical scanner. In vitro experiments were performed for testing of CEST-NMR contrast of AAV2 capsids under varying pH, density, biological transduction stage, and across multiple serotypes and mixed biological media. Reverse transcriptase-polymerase chain reaction was used to quantify virus concentration. Subsequent experiments at 7 T optimized CEST saturation schemes for AAV contrast detection and detected AAV2 particles encapsulated in a biocompatible hydrogel administered in the hind limb of mice. RESULTS: CEST-NMR experiments revealed CEST contrast up to 52% for AAV2 viral capsids between 0.6 and 0.8 ppm. CEST contrast generated by AAV2 demonstrated high levels of CEST contrast across a variety of chemical environments, concentrations, and saturation schemes. AAV2 CEST contrast displayed significant positive correlations with capsid density (R2 > 0.99, p < 0.001), pH (R2 = 0.97, p = 0.01), and viral titer per cell count (R2 = 0.92, p < 0.001). Transition to a preclinical field strength yielded up to 11.8% CEST contrast following optimization of saturation parameters. In vivo detection revealed statistically significant molecular contrast between viral and empty hydrogels using both mean values (4.67 ± 0.75% AAV2 vs. 3.47 ± 0.87% empty hydrogel, p = 0.02) and quantile analysis. CONCLUSION: AAV2 viral capsids exhibit strong capacity as an endogenous CEST contrast agent and can potentially be used for monitoring and evaluation of AAV vector-mediated gene therapy protocols.

Identification of a novel hormone sensitive lipase inhibitor with a reduced potential of reactive metabolites formation.

Hormone sensitive lipase (HSL) has emerged as an attractive target for the treatment of dyslipidemia. We previously reported compound 1 as a potent and orally active HSL inhibitor. Although an attractive profile was demonstrated, subsequent studies revealed that compound 1 has a bioactivation liability. The oxygen-carbon linker in compound 1 was identified as being potentially responsible for reactive metabolite formation. By exchanging of this susceptible fragment was feasible, and a benzanilide derivative 6b with a decreased bioactivation liability was obtained. Further modification of the novel benzanilide scaffold resulted in the identification of compound 24b. Compound 24b exhibited potent HSL inhibitory activity (IC50=2nM) with a significantly reduced bioactivation potential. Oral administration of compound 24b exhibited an antilipolytic effect on rats at 3mg/kg.

Design, synthesis, and pharmacological evaluation of a novel series of hormone sensitive lipase inhibitor.

HSL inhibition is a promising approach to the treatment of dyslipidemia. As a result of re-optimization of lead compound 2, we identified novel compound 25a exhibiting potent inhibitory activity against HSL enzyme and cell with high selectivity for cholinesterases (AChE and BuChE). Reflecting its potent in vitro activity, compound 25a exhibited antilipolytic effect in rats at 1mg/kg p.o., which indicated that this novel compound is the most potent orally active HSL inhibitor. Moreover, compound 25a did not show bioactivation liability.

Identification of a novel boronic acid as a potent, selective, and orally active hormone sensitive lipase inhibitor.

Hormone sensitive lipase (HSL) is an attractive therapeutic target of dyslipidemia. We designed and synthesized several compounds as reversible HSL inhibitors with a focus on hydrophobic interactions, which was thought to be effective upon the HSL inhibitory activity. In these efforts, we identified boronated compound 12 showing a potent HSL inhibitory activity with an IC50 value of 7nM and a high selectivity against cholinesterases. Furthermore, compound 12 is the first boron containing HSL inhibitor that has shown an antilipolytic effect in rats after oral administration at 3mg/kg.

Perturbation-Based Proteomic Correlation Profiling as a Target Deconvolution Methodology.

Molecular target identification of small molecules, so-called target deconvolution, is a major obstacle to phenotype-based drug discovery. Here, we developed an approach called perturbation-based proteomic correlation profiling (PPCP) utilizing the correlation between protein quantity and binding activity of compounds under cellular perturbation by gene silencing and successfully identified lanosterol synthase as a molecular target of TGF-ß pathway inhibitor. This PPCP concept was extended to the use of a cell line panel and provides a new option for target deconvolution.