A Chemical-Enhanced System for CRISPR-Based Nucleic Acid Detection (preprint)

The CRISPR-based nucleic acid detection systems such as SHERLOCK, DETECTR and HOLMES have shown great potential for point-of-care testing of viral pathogens, especially in the context of COVID-19 pandemic. Here we optimize several key parameters of reaction chemistry and develop a Chemical Enhanced CRISPR Detection system for nucleic acid (termed CECRID). For the Cas12a/Cas13a-based signal detection phase, we determine buffer conditions and substrate range for optimal detection performance. By comparing several chemical additives, we find that addition of L-proline can secure or enhance Cas12a/Cas13a detection capability. For isothermal amplification phase with typical LAMP and RPA methods, inclusion of L-proline can also enhance specific target amplification as determined by CRISPR detection. Using SARS-CoV-2 pseudovirus, we demonstrate CECRID has enhanced detection sensitivity over chemical additive-null method with either fluorescence or lateral flow strip readout. Thus, CECRID provides an improved detection power and system robustness towards practical application of CRISPR-based diagnostics.

A Computational Framework of Host-Based Drug Repositioning for Broad-Spectrum Antivirals against RNA Viruses (preprint)

RNA viruses are responsible for many types of zoonotic diseases that post great challenges for public health system. Effective therapeutics against these viral infections remains limited. Here we deployed a computational framework for host-based drug repositioning to predict potential antiviral drug candidates from 2352 approved drugs and 1062 natural compounds embedded in Traditional Chinese Medicine herbs. By systematically interrogating public genetic screening data, we comprehensively catalogued human-specific host dependency genes that are indispensable for the successful viral infection corresponding to 10 families and 29 species of RNA viruses. In addition, we utilized these host dependency genes as potential drug targets, and interrogated extensive drug-target interactions through multiple ways such as database retrieval, literature mining and de novo prediction using artificial intelligence-based algorithms. Repurposed drugs or natural compounds were proposed for combating many viral pathogens such as coronaviruses (e.g., SARS-CoV-2), flaviviruses (e.g., Zika virus) and influenza viruses. This study helps to prioritize promising drug candidates for further therapeutic evaluation against these viral-related diseases.