Current trends in application of CRISPR/Cas9 in gene editing and diagnostics in Neglected tropical diseases (NTDs).

Abstract

Neglected tropical diseases (NTDs) include more than a dozen of diseases which despite their fatality receive less attention from the research community worldwide. High cost diagnosis of these diseases and lack of trained community which can accurately interpret them is the major drawback in the healthcare system. Nowadays, in the genetic engineering era more emphasis is given to the modern gene editing tools such as Transcription Activator-Like Effector Nucleases (TALENS), Zinc Finger Nucleases (ZFNs) and Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) due to their unique tailoring molecular machinery. This review article details the applicability of CRISPR/Cas9 as a modern gene editing tool in case of NTD parasites such as trypanosomatids with an aim to target their virulent genes. It has been observed through a number of studies that knocking in/out virulent genes of these parasites have led to a significant decrease in infectivity, growth rates along with morphological defects. The article also mentions various advanced CRISPR/Cas based diagnostics such as Specific High-Sensitivity Enzymatic Reporter unLOCKing (SHERLOCK) and SHERLOCK4HAT which can detect parasite concentration as low as 2 attomolar/L (aM: 10^- 18) and 1 parasite/µL respectively. This review also enlists various regulatory and biosafety issues, for example ecological imbalance which can arise as a consequence of CRISPR/Cas based gene drives employed to target parasitic vectors. Despite its wide applications, CRISPR/Cas is associated with several limitations like off-target effects and ecological imbalance to name a few.