{'fraction_non_alphanumeric': 0.03143418467583497, 'fraction_numerical': 0.0091683038637852, 'mean_word_length': 5.262295081967213, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Efficient inhibition of beta-secretase gene expression in HEK293 cells by tRNAVal-driven and CTE-helicase associated hammerhead ribozymes.

The beta-amyloid peptide (Abeta) is a major component of toxic amyloid plaques found in the brains of patients with Alzheimer's disease. Abeta is liberated by sequential cleavage of amyloid precursor protein (APP) by beta- and gamma-secretases. The level of Abeta depends directly on the hydrolytic activity of beta-secretase. Therefore, beta-secretase is an excellent target for drug design. An approach based on RNA-cleaving ribozymes was developed to control expression of beta-secretase. Two sites of mRNA coding beta-site APP cleaving enzyme were chosen as target sequences for endogenously delivered ribozymes. The ribozyme cassette was designed to constitute a catalytic hammerhead core and substrate recognition arms, flanked at the 5'-terminus by tRNAVal and at the 3'-terminus by constitutive transport element sequences. Ribozyme cassettes were cloned into a pUC19 plasmid and used for transient transfection of HEK293 cells. We demonstrate that such ribozymes efficiently inhibit beta-secretase gene expression at both the mRNA (up to 95%) and the protein (up to 90%) levels. Inhibition of beta-site APP cleaving enzyme activity directly influences the intra- and extracellular population of Abeta peptide. Therefore, such ribozymes may be considered as molecular tools for silencing the beta-secretase activity, and further, as therapeutic agents for anti-amyloid treatment.