An efficient CRISPR interference-based prediction method for synergistic/additive effects of novel combinations of anti-tuberculosis drugs

BCG-derived acellular membrane vesicles elicit antimycobacterial immunity and innate immune memory

Tuberculosis (TB) is one of the leading causes of death due to infectious disease. The sole established vaccine against TB is the Mycobacterium bovis Bacillus Calmette-Guerin (BCG) vaccine. However, owing to the lack of durable immunity with the BCG vaccine and its risk of infection, safer vaccines that can also be used as boosters are needed. Here, we examined whether membrane vesicles (MVs) from BCG (BCG-MVs) isolated from BCG statically cultured in nutrient-restricted Sauton's medium (s-MVs) and from BCG planktonically cultured in nutrient-rich medium commonly used in the laboratory (p-MVs) could be used as novel TB vaccines. MVs are extracellular vesicles produced by various bacteria, including mycobacteria. Differences in the culture conditions affected the morphology, contents, immunostimulatory activity and immunogenicity of BCG-MVs. s-MVs presented greater immunostimulatory activity than p-MVs via the induction of TLR2 signaling. Mouse immunization experiments revealed that s-MVs, but not p-MVs, induced mycobacterial humoral and mucosal immunity, especially when administered in combination with adjuvants. In a BCG challenge experiment using BCG Tokyo type I carrying pMV361-Km, subcutaneous vaccination with s-MVs reduced the bacterial burden in the mouse lung to a level similar to that after intradermal vaccination with live BCG. Furthermore, the administration of s-MVs induced a significant lipopolysaccharide-induced proinflammatory response in macrophages in vitro. These results indicate that BCG-MVs obtained from static culture in Sauton's medium induce not only humoral immunity against mycobacteria but also trained immunity, which can allow the clearance of infectious agents other than mycobacteria. Together, these findings highlight the immunological properties of BCG-MVs and the availability of acellular TB vaccines that confer broad protection against various infectious diseases.

The CRISPR-dCas9 interference system suppresses inhA gene expression in Mycobacterium smegmatis

CRISPR-dead Cas9 interference (CRISPRi) has become a valuable tool for precise gene regulation. In this study, CRISPRi was designed to target the inhA gene of Mycobacterium smegmatis (Msm), a gene necessary for mycolic acid synthesis. Our findings revealed that sgRNA2 induced with 100 ng/ml aTc achieved over 90% downregulation of inhA gene expression and inhibited bacterial viability by approximately 1,000-fold. Furthermore, CRISPRi enhanced the susceptibility of M. smegmatis to isoniazid and rifampicin, which are both 50% and 90% lower than those of the wild-type strain or other strains, respectively. This study highlights the ability of CRISPRi to silence the inhA gene, which impacts bacterial viability and drug susceptibility. The findings provide valuable insights into the utility of CRISPRi as an alternative tool for gene regulation. CRISPRi might be further assessed for its synergistic effect with current anti-tuberculosis drugs and its possible implications for combating mycobacterial infections, especially drug-resistant tuberculosis.

Identification of Mycobacterium tuberculosis Resistance to Common Antibiotics: An Overview of Current Methods and Techniques

Multidrug-resistant tuberculosis (MDR-TB) is an essential cause of tuberculosis treatment failure and death of tuberculosis patients. The rapid and reliable profiling of Mycobacterium tuberculosis (MTB) drug resistance in the early stage is a critical research area for public health. Then, most traditional approaches for detecting MTB are time-consuming and costly, leading to the inappropriate therapeutic schedule resting on the ambiguous information of MTB drug resistance, increasing patient economic burden, morbidity, and mortality. Therefore, novel diagnosis methods are frequently required to meet the emerging challenges of MTB drug resistance distinguish. Considering the difficulty in treating MDR-TB, it is urgently required for the development of rapid and accurate methods in the identification of drug resistance profiles of MTB in clinical diagnosis. This review discussed recent advances in MTB drug resistance detection, focusing on developing emerging approaches and their applications in tangled clinical situations. In particular, a brief overview of antibiotic resistance to MTB was present, referred to as intrinsic bacterial resistance, consisting of cell wall barriers and efflux pumping action and acquired resistance caused by genetic mutations. Then, different drug susceptibility test (DST) methods were described, including phenotype DST, genotype DST and novel DST methods. The phenotype DST includes nitrate reductase assay, RocheTM solid ratio method, and liquid culture method and genotype DST includes fluorescent PCR, GeneXpert, PCR reverse dot hybridization, ddPCR, next-generation sequencing and gene chips. Then, novel DST methods were described, including metabolism testing, cell-free DNA probe, CRISPR assay, and spectral analysis technique. The limitations, challenges, and perspectives of different techniques for drug resistance are also discussed. These methods significantly improve the detection sensitivity and accuracy of multidrug-resistant tuberculosis (MRT) and can effectively curb the incidence of drug-resistant tuberculosis and accelerate the process of tuberculosis eradication.

Application of CRISPR-cas-based technology for the identification of tuberculosis, drug discovery and vaccine development

Tuberculosis (TB), which caused by Mycobacterium tuberculosis, is the leading cause of death from a single infectious agent and continues to be a major public health burden for the global community. Despite being the only globally licenced prophylactic vaccine, Bacillus Calmette-Guérin (BCG) has multiple deficiencies, and effective diagnostic and therapeutic options are limited. Clustered regularly interspaced short palindromic repeats (CRISPR)-Cas (CRISPR-associated proteins) is an adaptive immune system that is found in bacteria and has great potential for the development of novel antituberculosis drugs and vaccines. In addition, CRISPR-Cas is currently recognized as a prospective tool for the development of therapies for TB infection with potential diagnostic and therapeutic value, and CRISPR-Cas may become a viable tool for eliminating TB in the future. Herein, we systematically summarize the current applications of CRISPR-Cas-based technology for TB detection and its potential roles in drug discovery and vaccine development.