Harnessing enhanced CRISPR/Cas12a trans-cleavage activity with extended reporters and reductants for early diagnosis of Helicobacter pylori, the causative agent of peptic ulcers and stomach cancer

Establishment of a rapid RAA-CRISPR/Cas12a system targeting the recN gene for on-site detection of Streptococcus suis in livestock and fresh pork meat

Streptococcus suis is a major bacterial pathogen in the swine industry, causing meningitis, arthritis, and other diseases in infected pigs. It also poses significant public health risks due to its zoonotic potential, particularly in individuals with skin lesions. Current detection methods, including traditional culture-based techniques and PCR assays, are time-consuming, labor-intensive, and lack sufficient accuracy. To address these limitations, this study aimed to develop a rapid and precise detection method for S. suis. By leveraging whole-genome sequencing (WGS) and multiple sequence alignment, the recN gene was identified as a highly specific molecular target. A novel isothermal detection method, integrating recombinase-aided amplification (RAA) with CRISPR/Cas12a, was subsequently established. This RAA-CRISPR/Cas12a-based system demonstrated superior sensitivity compared to conventional PCR (targeting the gdh gene), achieving detection within 30 min without requiring specialized equipment. This method achieves 2.44 × 101 copies/µL and 2.1 × 101 CFU sensitivity and 100% specificity within 30 min, outperforming conventional PCR in speed and reliability while eliminating dependency on specialized equipment. Designed for field applications, it offers a cost-effective (US$1/test), user-friendly solution for on-site S. suis detection in swine farms and fresh pork meat, enhancing outbreak control and preventive healthcare in the livestock industry.

Dithiothreitol Facilitates LbCas12a with Expanded PAM Preference for Ultrasensitive Nucleic Acid Detection

Clustered regularly interspaced short palindromic repeats-associated (CRISPR/Cas) proteins have been used for a growing class of in vitro molecular diagnostics due to their modularity and high specificity in targeting nucleic acid. However, the requirement of a protospacer adjacent motif (PAM) for Cas protein-catalyzed trans-cleavage poses a challenge for random nucleic acid detection. Here, we demonstrate that dithiothreitol (DTT) enables LbCas12a to adopt a relaxed preference for PAM base pairing, thereby expanding the target sequence space. Accordingly, we propose a DTT-mediated CRISPR/Cas12a toolbox (DTT-deCRISPR) that exhibits relaxed PAM specificity and is readily compatible with nucleic acid amplification techniques including recombinase polymerase amplification (RPA) and polymerase chain reaction (PCR). As a proof of concept, we integrate DTT-deCRISPR with frequently used PCR for sensitively and selectively detecting high-risk human papillomavirus (HPV) 16 and 18. The platform demonstrates the ability to detect synthesized HPV 16 and 18 plasmids down to 1 aM within 60 min. Based on the receiver operating characteristic curve analysis, the clinical sensitivities of the developed method for detecting HPV 16 and 18 are 93.75% and 80.00%, respectively. We further incorporate it into a lateral flow assay (LFA) for point-of-care detection, and the HPV 16 and HPV 18 abundances determined by LFA for clinical samples are consistent with the fluorescence analysis results. Together, this work uncovers an unexpected connection between DTT and PAM preferences of LbCas12a, promoting the universality and flexibility of CRISPR technology in molecular diagnostics.

Concurrent Detection of Protein and miRNA at the Single Extracellular Vesicle Level Using a Digital Dual CRISPR-Cas Assay

The simultaneous detection of proteins and microRNA (miRNA) at the single extracellular vesicle (EV) level shows great promise for precise disease profiling, owing to the heterogeneity and scarcity of tumor-derived EVs. However, a highly reliable method for multiple-target analysis of single EVs remains to be developed. In this study, a digital dual CRISPR-Cas-powered Single EV Evaluation (ddSEE) system was proposed to enable the concurrent detection of surface protein and inner miRNA of EVs at the single-molecule level. By optimizing simultaneous reaction conditions of CRISPR-Cas12a and CRISPR-Cas13a, the surface protein of EVs was detected by Cas12a using antibody-DNA conjugates to transfer the signal of the protein to DNA, while the inner miRNA was analyzed by Cas13a through EV-liposome fusion. A microfluidic chip containing 188,000 microwells was used to convert the CRISPR-Cas system into a digital assay format to enable the absolute quantification of miRNA/protein-positive EVs without bias through fluorescence imaging, which can detect as few as 214 EVs/μL. Finally, a total of 31 blood samples, 21 from breast cancer patients and 10 from healthy donors, were collected and tested, achieving a diagnostic accuracy of 92% in distinguishing patients with breast cancer from healthy donors. With its absolute quantification, ease of use, and multiplexed detection capability, the ddSEE system demonstrates its great potential for both EV research and clinical applications.

Development and evaluation of a CRISPR/Cas12a-based diagnostic test for rapid detection and genotyping of HR-HPV in clinical specimens

Persistent infection with high-risk human papillomavirus (HR-HPV) is the principal etiological factor of cervical cancer. Considering the gradual progression of cervical cancer, the early, rapid, sensitive, and specific identification of HPV, particularly HR-HPV types, is crucial in halting the advancement of the illness. Here, we established a rapid, highly sensitive, and specific HR-HPV detection platform, leveraging the CRISPR/Cas12a assay in conjunction with multienzyme isothermal rapid amplification. Our platform enables the detection and genotyping of 14 types of HR-HPV by using type-specific crRNAs. The outcomes of the detection can be interpreted either through a fluorescence reader or visually. Furthermore, we achieved one-tube multiplex detection of 14 HR-HPV types through the use of multiple amplifications and a crRNA pool. The detection sensitivity of this method is 2 copies/μL with no cross-reactivity, and the results can be obtained within 30 minutes. This method exhibited 100% clinical sensitivity and 100% clinical specificity when applied to 258 clinical specimens. Based on these findings, our CRISPR/Cas-based HR-HPV detection platform holds promise as a novel clinical detection tool, offering a visually intuitive and expedited alternative to existing HPV infection diagnostics and providing fresh perspectives for clinical cervical cancer screening.IMPORTANCEThis study developed a novel high-risk human papillomavirus (HR-HPV) detection platform based on CRISPR/Cas12a technology. This platform not only enables the rapid, highly sensitive, and specific detection and genotyping of 14 types of HR-HPV but also achieves single-tube multiplex detection of 14 HR-HPV types through ingenious design. The outcomes of the detection can be interpreted either through a fluorescence reader or visually. To the best of our knowledge, this is the first paper to utilize CRISPR/Cas diagnostic technology for the simultaneous detection of 14 types of HPV and to evaluate its feasibility in clinical sample detection using a large number of clinical samples. We hope that this work will facilitate the rapid and accurate detection of HPV and promote the broader application of CRISPR/Cas diagnostic technology.

Advances in Helicobacter pylori Antimicrobial Resistance Detection: From Culture-Based to Multi-Omics-Based Technologies

Helicobacter pylori (H. pylori), a proven carcinogenic microbe, necessitates antimicrobial treatment once infected. However, H. pylori worldwide currently faces serious antibiotic resistance (AMR), requiring infected patients to undergo antibiotic susceptibility testing (AST) to guide therapy. Currently, the recommended ASTs for H. pylori are culture-based methods, which are time-consuming, complicated, and expensive, impeding their widespread application. With in-depth researches on the AMR mechanisms of H. pylori, specific gene mutations and novel proteins have been confirmed as the cause of AMR and can serve as targets of ASTs. Accordingly, molecular biology detection has been developed and tremendously shortened the time and reduced difficulty of AST. However, these assays still struggle to meet the enormous testing demand and need for even faster, simpler, and more accurate methods. In recent years, researchers have developed various new platforms based on biosensors, transcriptomics, proteomics, and single-cell analysis. This review introduces the AMR mechanisms of H. pylori and summarizes the current ASTs from the working principles to application characteristics. Additionally, we draw attention to the potentially applicable techniques for AST of H. pylori from DNA, RNA, protein, and cell perspectives. By systematically recapitulating the past, present, and future of AST for H. pylori, this review provides valuable insights for developing novel assays.

Precise pathogen quantification by CRISPR-Cas: a sweet but tough nut to crack

Pathogen detection is increasingly applied in medical diagnosis, food processing and safety, and environmental monitoring. Rapid, sensitive, and accurate pathogen quantification is the most critical prerequisite for assessing protocols and preventing risks. Among various methods evolved, those based on clustered regularly interspaced short palindromic repeats (CRISPR)-associated proteins (Cas) have been developed as important pathogen detection strategies due to their distinct advantages of rapid target recognition, programmability, ultra-specificity, and potential for scalability of point-of-care testing (POCT). However, arguments and concerns on the quantitative capability of CRISPR-based strategies are ongoing. Herein, we systematically overview CRISPR-based pathogen quantification strategies according to the principles, properties, and application scenarios. Notably, we review future challenges and perspectives to address the of precise pathogen quantification by CRISPR-Cas. We hope the insights presented in this review will benefit development of CRISPR-based pathogen detection methods.

The clinical value of rapidly detecting urinary exosomal lncRNA RMRP in bladder cancer with an RT-RAA-CRISPR/Cas12a method

BACKGROUND AND AIMS

Bladder cancer (BCa) is a highly aggressive malignancy of the urinary system. Timely detection is imperative for enhancing BCa patient prognosis.

MATERIALS AND METHODS

This study introduces a novel approach for detecting long non-coding RNA (lncRNA) Mitochondrial RNA Processing Endoribonuclease (RMRP) in urine exosomes from BCa patients using the reverse transcription recombinase-aided amplification (RT-RAA) and clustered regularly interspaced short palindromic repeats and associated Cas12a proteins (CRISPR/Cas12a) technique. Various statistical methods were used to evaluate its diagnostic value for BCa.

RESULTS

The specificity of urine exosomal RMRP detection for BCa diagnosis was enhanced by using RT-RAA combined with CRISPR/Cas12a. The testing process duration was reduced to 30 min, which supports rapid detection. Moreover, this approach allows the identification of target signals in real-time using blue light, facilitating immediate detection. In clinical sample analysis, this methodology exhibited a high level of diagnostic efficacy. This was evidenced by larger area under the curve values with receiver operating characteristic curve analysis compared with using traditional RT-qPCR methods, indicating superior diagnostic accuracy and sensitivity. Furthermore, the combined analysis of RMRP expression in urine exosomes detected by RT-RAA-CRISPR/Cas12a and NMP-22 expression may further enhance diagnostic accuracy.

CONCLUSIONS

The RT-RAA-CRISPR/Cas12a technology is a swift, sensitive, and uncomplicated method for nucleic acid detection. Because of its convenient and non-invasive sampling approach, user-friendly operation, and reproducibility, this technology is very promising for automated detection and holds favorable application possibilities within clinical environments.

Novel therapeutic regimens against Helicobacter pylori: an updated systematic review

Helicobacter pylori (H. pylori) is a strict microaerophilic bacterial species that exists in the stomach, and H. pylori infection is one of the most common chronic bacterial infections affecting humans. Eradicating H. pylori is the preferred method for the long-term prevention of complications such as chronic gastritis, peptic ulcers, gastric mucosa-associated lymphoid tissue lymphoma, and gastric cancer. However, first-line treatment with triple therapy and quadruple therapy has been unable to cope with increasing antibacterial resistance. To provide an updated review of H. pylori infections and antibacterial resistance, as well as related treatment options, we searched PubMed for articles published until March 2024. The key search terms were "H. pylori", "H. pylori infection", "H. pylori diseases", "H. pylori eradication", and "H. pylori antibacterial resistance." Despite the use of antimicrobial agents, the annual decline in the eradication rate of H. pylori continues. Emerging eradication therapies, such as the development of the new strong acid blocker vonoprazan, probiotic adjuvant therapy, and H. pylori vaccine therapy, are exciting. However, the effectiveness of these treatments needs to be further evaluated. It is worth mentioning that the idea of altering the oxygen environment in gastric juice for H. pylori to not be able to survive is a hot topic that should be considered in new eradication plans. Various strategies for eradicating H. pylori, including antibacterials, vaccines, probiotics, and biomaterials, are continuously evolving. A novel approach involving the alteration of the oxygen concentration within the growth environment of H. pylori has emerged as a promising eradication strategy.

Utilizing fab fragment-conjugated surface plasmon resonance-based biosensor for detection of Salmonella Enteritidis

Although antibodies, a key element of biorecognition, are frequently used as biosensor probes, the use of these large molecules can lead to adverse effects. Fab fragments can be reduced to allow proper antigen-binding orientation via thiol groups containing Fab sites that can directly penetrate Au sites chemically. In this study, the ability of the surface plasmon resonance (SPR) sensor to detect Salmonella was studied. Tris(2-carboxyethyl)phosphine was used as a reducing agent to obtain half antibody fragments. Sensor surface was immobilized with antibody, and bacteria suspensions were injected from low to high concentrations. Response units were changed by binding first reduced antibody fragments, then bacteria. The biosensor was able to determine the bacterial concentrations between 103 and 108 CFU/mL. Based on these results, the half antibody fragmentation method can be generalized for faster, label-free, sensitive, and selective detection of other bacteria species.

Non-canonical CRISPR/Cas12a-based technology: A novel horizon for biosensing in nucleic acid detection

Nucleic acids are essential biomarkers in molecular diagnostics. The CRISPR/Cas system has been widely used for nucleic acid detection. Moreover, canonical CRISPR/Cas12a based biosensors can specifically recognize and cleave target DNA, as well as single-strand DNA serving as reporter probe, which have become a super star in recent years in the field of nucleic acid detection due to its high specificity, universal programmability and simple operation. However, canonical CRISPR/Cas12a based biosensors are hard to meet the requirements of higher sensitivity, higher specificity, higher efficiency, larger target scope, easier operation, multiplexing, low cost and diversified signal reading. Then, advanced non-canonical CRISPR/Cas12a based biosensors emerge. In this review, applications of non-canonical CRISPR/Cas12a-based biosensors in nucleic acid detection are summarized. And the principles, peculiarities, performances and perspectives of these non-canonical CRISPR/Cas12a based biosensors are also discussed.

Sodium sulfite-driven Helicobacter pylori eradication: Unraveling oxygen dynamics through multi-omics investigation

Due to the emergence and spread of multidrug resistance in Helicobacter pylori (H. pylori), its eradication has become difficult. Sodium sulfite (SS), a widely used food additive for ensuring food safety and storage, has been recognized as an effective nonbactericidal agent for H. pylori eradication. However, the mechanism by which H. pylori adapts and eventually succumbs under low- or no-oxygen conditions remains unknown. In this study, we aimed to evaluate the anti-H. pylori effect of SS and investigated the multiomics mechanism by which SS kills H. pylori. The results demonstrated that SS effectively eradicated H. pylori both in vitro and in vivo. H. pylori responds to the oxygen changes regulated by SS, downregulates the HcpE gene, which is responsible for redox homeostasis in bacteria, decreases the activities of enzymes related to oxidative stress, and disrupts the outer membrane structure, increasing susceptibility to oxidative stress. Furthermore, SS downregulates the content of cytochrome C in the microaerobic respiratory chain, leading to a sharp decrease in ATP synthesis. Consequently, the accumulation of triglycerides (TGs) in bacteria due to oxidative stress supports anaerobic respiration, meeting their energy requirements. The multifaceted death of H. pylori caused by SS does not result in drug resistance. Thus, screening of the redox homeostasis of HcpE as a new target for H. pylori infection treatment could lead to the development of a novel approach for H. pylori eradication therapy.

Recent progress on the CRISPR/Cas system in optical biosensors

Clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) protein systems are adaptive immune systems unique to archaea and bacteria, with the characteristics of targeted recognition and gene editing to resist the invasion of foreign nucleic acids. Biosensors combined with the CRISPR/Cas system and optical detection technology have attracted much attention in medical diagnoses, food safety, agricultural progress, and environmental monitoring owing to their good sensitivity, high selectivity, and fast detection efficiency. In this review, we introduce the mechanism of CRISPR/Cas systems and developments in this area, followed by summarizing recent progress on CRISPR/Cas system-based optical biosensors combined with colorimetric, fluorescence, electrochemiluminescence and surface-enhanced Raman scattering optical techniques in various fields. Finally, we discuss the challenges and future perspectives of CRISPR/Cas systems in optical biosensors.

A Rationally Designed CRISPR/Cas12a Assay Using a Multimodal Reporter for Various Readouts

The CRISPR/Cas systems offer a programmable platform for nucleic acid detection, and CRISPR/Cas-based diagnostics (CRISPR-Dx) have demonstrated the ability to target nucleic acids with greater accuracy and flexibility. However, due to the configuration of the reporter and the underlying labeling mechanism, almost all reported CRISPR-Dx rely on a single-option readout, resulting in limitations in end-point result readouts. This is also associated with high reagent consumption and delays in diagnostic reports due to protocol differences. Herein, we report for the first time a rationally designed Cas12a-based multimodal universal reporter (CAMURE) with improved sensitivity that harnesses a dual-mode reporting system, facilitating options in end-point readouts. Through systematic configurations and optimizations, our novel universal reporter achieved a 10-fold sensitivity enhancement compared to the DETECTR reporter. Our unique and versatile reporter could be paired with various readouts, conveying the same diagnostic results. We applied our novel reporter for the detection of staphylococcal enterotoxin A due to its high implication in staphylococcal food poisoning. Integrated with loop-mediated isothermal amplification, our multimodal reporter achieved 10 CFU/mL sensitivity and excellent specificity using a real-time fluorimeter, in-tube fluorescence, and lateral flow strip readouts. We also propose, using artificially contaminated milk samples, a fast (2-5 min) Triton X-100 DNA extraction approach with a comparable yield to the commercial extraction kit. Our CAMURE could be leveraged to detect all gene-encoding SEs by simply reprogramming the guide RNA and could also be applied to the detection of other infections and disease biomarkers.

CRISPR/Cas genome editing in triple negative breast cancer: Current situation and future directions

Triple negative breast cancer (TNBC) has been well-known to be closely associated with the abnormal expression of both oncogenes and tumor suppressors. Although several pathogenic mutations in TNBC have been identified, the current therapeutic strategy is usually aimed at symptom relief rather than correcting mutations in the DNA sequence. Of note, clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas) has been gradually regarded as a breakthrough gene-editing tool with potential therapeutic applications in human cancers, including TNBC. Thus, in this review, we focus on summarizing the molecular subtypes of TNBC, as well as the CRISPR system and its potential applications in TNBC treatment. Moreover, we further discuss several emerging strategies for utilizing the CRISPR/Cas system to aid in the precise diagnosis of TNBC, as well as the limitations of the CRISPR/Cas system. Taken together, these findings would demonstrate that CRISPR/Cas system is not only an effective genome editing tool in TNBC, but a promising strategy for the future therapeutic purposes.