1.The Versatile Tool: CRISPR/Cas12a System for Nucleic Acid Detection
Sheng DANG ; Shuai ZHANG ; Jing-Bo ZHAI
Progress in Biochemistry and Biophysics 2024;51(4):785-796
The CRISPR/Cas system consists of clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated genes (Cas). The system forms an adaptive immune system in archaea and bacteria. The inherent defense mechanism enables these microorganisms to protect themselves against the invasion of foreign genetic material. The system functions of immune response including three main stages: adaptation, expression/maturation, and interference, each stage needs specific Cas proteins encoded by Cas gene located near the CRISPR sequences, along with other auxiliary proteins. In 2015, Zhang et al. reportedCas12a (Cpf1) as a member of the Class II type V CRISPR/Cas12a system, which possesses endonuclease activity. This finding holds great promise for its application in the field of biotechnology. In 2018, Doudna’s team first applied the CRISPR/Cas12a system for detecting HPV nucleic acid. The system comprises the following essential components in vitro detection: Cas12a, the crRNA sequence complementary to the target DNA, the PAM sequence, and the ssDNA reporter. Cas12a possesses a typical RuvC domain, displaying a canonical bilobed architecture that consists of a recognition (REC) lobe and a nuclease (NUC) lobe. The REC lobe contains the REC1 and REC2 domains, and the NUC lobe includes RuvC, PAM-interacting (PI), Wedge (WED), and bridge helix (BH) domains. The mature crRNA for Cas12a has a length of 42-44 nt, consists of repeat sequence (19/20 nt) and spacer sequence (23-25 nt). The crRNA spacer sequence has been found to require a length of 18 nt to achieve complete cleavage activity in vitro. Additionally, mutation in the bases of crRNA can indeed affect the activity of Cas12a. The PAM sequence plays a critical role in the recognition and degradation of DNA by the CRISPR/Cas system, enabling the system to distinguish between self and non-self genomic materials. Cas12a can effectively target the spacer sequence downstream of a T-rich PAM sequence at the 5' end. LbCas12a and AsCas12a both recognize the PAM sequences of 5'-TTTN-3', while FnCas12a recognizes the PAM sequences of 5'-TTN-3'. All of these PAM sequences are located upstream on the non-template strand (NTS) at the 5' end. Cas12a (Cpf1), guided by the crRNA, binds to the target DNA by recognizing the PAM sequence. It exhibits the ability to induce arbitrary cleavage of ssDNA within the system while cleaving the target ssDNA or dsDNA. According to this feature, an array of nucleic acid detection methods has been developed for tumor detection and infection diagnostics, such as the DETECTR (RPA-CRISPR/Cas12a method) and HOLMES (PCR-CRISPR/Cas12a method) in 2018. Then, in 2019, Cas12aVDet (one-step detection method), where Cas12a protein was immobilized on the upper wall of the reaction tube. This not only prevented contamination from opening the tube but also reduced the detection reaction time. In 2021, the dWS-CRISPR (digital warm-start CRISPR) was developed as a one-pot detection method. It serves as an accurate approach for quantitatively detectingSARS-CoV-2 in clinical specimens. With the innovation of scientific technology, the high-sensitivity signal transduction technology has also been integrated with the CRISPR/Cas12a system, enabling direct detection of nucleic acids, and eliminating the need for nucleic acid amplification steps. Here, we elaborated the detection principles of CRISPR/Cas12a in in vitro detection. We discussed the different stages leading to the catalytic pathway of target DNA, and the practical applications of Cas12a in nucleic acid detection. These findings revealed a target interference mechanism that originates from the binding of Cas12a-guided RNA complex to complementary DNA sequences within PAM-dependent (dsDNA) regions. The crRNA-DNA binding activates Cas12a, enabling site-specific dsDNA cleavage and non-specific ssDNA trans-cleavage. The release of Cas12a ssDNase activity provides a novel approach to enhance the sensitivity and specificity of molecular diagnostic applications. Before these CRISPR/Cas12a-based nucleic acid detection methods can be introduced into clinical use, substantial work is still required to ensure the accuracy of diagnosis. Nevertheless, we believe that these innovative detection tools based on CRISPR/Cas will revolutionize future diagnostic technologies, particularly offering significant assistance in pathogen infection diagnosis for developing countries with relatively poor healthcare conditions and high prevalence of infectious diseases.
2.Oral health education for pregnant women: a scoping review
Yemin XIE ; Ting SHUAI ; Lu GAN ; Yun DANG ; Jingcheng WEN ; Yan XUAN ; Xiue LI
Chinese Journal of Modern Nursing 2024;30(19):2625-2636
Objective:To summarize the research on oral health education for pregnant women.Methods:The literature was described and analyzed using a scoping review method. Seven databases, such as PubMed, Embase, Web of Science, China National Knowledge Infrastructure, and WanFang Data, were electronically searched, and the search period was from database establishment to October 30, 2023.Results:A total of 43 articles were included. The implementers of health education were mainly dental professionals and prenatal healthcare personnel. The theoretical basis included the health belief model, planned behavior theory, social cognitive model and so on. The methods involved traditional teaching or lectures, family-centered, internet-based, and motivational interviews. The contents contained many aspects of oral health for pregnant women. The evaluation indicators mainly covered oral health knowledge, attitude and practice, and self-efficacy, oral health beliefs, oral health status, the incidence of oral diseases, adverse pregnancy outcomes of pregnant and postpartum women, and childhood caries incidence.Conclusions:We should establish a cooperation team of the Department of Stomatology and Obstetrics and Gynecology, incorporate oral health for pregnant women into prenatal care projects, fully utilize the platform of pregnant women's schools, explore the optimal theoretical basis for oral health education, and improve the content of oral health education for pregnant women.
3.Effectiveness and safety of modified decompressive craniectomy for traumatic brain injury and its impact on inflammatory mediators and prognosis
Ming-Guo WANG ; Shuai DANG ; Yu YAN
Medical Journal of Chinese People's Liberation Army 2023;48(11):1338-1343
Objective To evaluate the efficacy and safety of modified decompressive craniectomy in treatment of traumatic brain injury and its impact on the serum levels of inflammatory mediators and prognosis.Methods According to different surgical methods,82 patients with traumatic brain injury admitted to the department of neurosurgery of Nanyang Central Hospital from June 2020 to January 2022 were divided into standard group(n=41)and modified group(n=41).The standard group was given standard decompressive craniectomy,and the modified group was given modified decompressive craniectomy.The intraoperative blood loss,operation time and hospital stay,the levels of neuron-specific enolase(NSE),S-100 calcium binding protein B(S-100β),C-reaction protein(CRP),procalcitonin(PCT),and interleukin-6(IL-6)before operation,6 hours after operation,and 3 days after operation,Glasgow Outcome Scale(GOS),incidence of complications,and incision healing grade 1 month after operation were compared between two groups.Results Compared with standard group,the hospital stay was significant shorter in modified group(P<0.05),and intraoperative blood loss and operation time were no significant difference in modified group(P>0.05).At 6 hours and 3 days after operation,the levels of NSE,S-100β,CRP,PCT and IL-6 in modified group were lower than those in standard group(P<0.05).Compared with standard group,the good prognosis rate based of GOS was higher in modified group[82.9%(34/41)vs.63.4%(26/41),P<0.05];the total incidence of complications was lower in modified group[2.4%(1/41)vs.19.5%(26/41),P<0.05];and the grade of incision healing was better in modified group(P<0.05).Conclusions Modified decompressive craniectomy in the treatment of traumatic brain injury could reduce stress of brain injury and surgical trauma,and the incidence of complications,help to speed up the postoperative recovery process,improve the rate of good prognosis and the grade of incision healing.Its efficacy and safety is better than standard decompressive craniectomy.
4.Effects of transcranial magneto-acoustic electrical stimulation on calcium signals in prefrontal nerve clusters.
Shuai ZHANG ; Jiankang WU ; Jiayue XU ; Junwu DANG ; Yihang ZHAO ; Wentao HOU ; Guizhi XU
Journal of Biomedical Engineering 2022;39(1):19-27
Transcranial magneto-acoustic electrical stimulation (TMAES) is a novel method of brain nerve regulation and research, which uses induction current generated by the coupling of ultrasound and magnetic field to regulate neural electrical activity in different brain regions. As the second special envoy of nerve signal, calcium plays a key role in nerve signal transmission. In order to investigate the effect of TMAES on prefrontal cortex electrical activity, 15 mice were divided into control group, ultrasound stimulation (TUS) group and TMAES group. The TMAES group received 2.6 W/cm 2 and 0.3 T of magnetic induction intensity, the TUS group received only ultrasound stimulation, and the control group received no ultrasound and magnetic field for one week. The calcium ion concentration in the prefrontal cortex of mice was recorded in real time by optical fiber photometric detection technology. The new object recognition experiment was conducted to compare the behavioral differences and the time-frequency distribution of calcium signal in each group. The results showed that the mean value of calcium transient signal in the TMAES group was (4.84 ± 0.11)% within 10 s after the stimulation, which was higher than that in the TUS group (4.40 ± 0.10)% and the control group (4.22 ± 0.08)%, and the waveform of calcium transient signal was slower, suggesting that calcium metabolism was faster. The main energy band of the TMAES group was 0-20 Hz, that of the TUS group was 0-12 Hz and that of the control group was 0-8 Hz. The cognitive index was 0.71 in the TMAES group, 0.63 in the TUS group, and 0.58 in the control group, indicating that both ultrasonic and magneto-acoustic stimulation could improve the cognitive ability of mice, but the effect of the TMAES group was better than that of the TUS group. These results suggest that TMAES can change the calcium homeostasis of prefrontal cortex nerve clusters, regulate the discharge activity of prefrontal nerve clusters, and promote cognitive function. The results of this study provide data support and reference for further exploration of the deep neural mechanism of TMAES.
Acoustics
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Animals
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Brain
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Calcium
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Electric Stimulation
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Mice
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Prefrontal Cortex
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Transcranial Direct Current Stimulation
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Transcranial Magnetic Stimulation
5.Phase amplitude coupling analysis of local field potentials in working memory of rats affected by transcranial magneto-acoustic-electrical stimulation.
Junwu DANG ; Shuai ZHANG ; Shengnan YOU ; Wenjing DU ; Guizhi XU
Journal of Biomedical Engineering 2022;39(2):267-275
Transcranial magneto-acoustic-electrical stimulation is a new non-invasive neuromodulation technology, in which the induced electric field generated by the coupling effect of ultrasound and static magnetic field are used to regulate the neural rhythm oscillation activity in the corresponding brain region. The purpose of this paper is to investigate the effects of transcranial magneto-acoustic-electrical stimulation on the information transfer and communication in neuronal clusters during memory. In the experiment, twenty healthy adult Wistar rats were randomly divided into a control group (five rats) and stimulation groups (fifteen rats). Transcranial magneto-acoustic-electrical stimulation of 0.05~0.15 T and 2.66~13.33 W/cm 2 was applied to the rats in stimulation groups, and no stimulation was applied to the rats in the control group. The local field potentials signals in the prefrontal cortex of rats during the T-maze working memory tasks were acquired. Then the coupling differences between delta rhythm phase, theta rhythm phase and gamma rhythm amplitude of rats in different parameter stimulation groups and control group were compared. The experimental results showed that the coupling intensity of delta and gamma rhythm in stimulation groups was significantly lower than that in the control group ( P<0.05), while the coupling intensity of theta and gamma rhythm was significantly higher than that in the control group ( P<0.05). With the increase of stimulation parameters, the degree of coupling between delta and gamma rhythm showed a decreasing trend, while the degree of coupling between theta and gamma rhythm tended to increase. The preliminary results of this paper indicated that transcranial magneto-acoustic-electrical stimulation inhibited delta rhythmic neuronal activity and enhanced the oscillation of theta and gamma rhythm in the prefrontal cortex, thus promoted the exchange and transmission of information between neuronal clusters in different spatial scales. This lays the foundation for further exploring the mechanism of transcranial magneto-acoustic-electrical stimulation in regulating brain memory function.
Acoustics
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Animals
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Electric Stimulation
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Memory, Short-Term/physiology*
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Rats
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Rats, Wistar
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Theta Rhythm/physiology*
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Transcranial Direct Current Stimulation
6.Pharmacological network-based study on quality control of Carthamus tinctorius L. for safflower injection
Xiao-ru HU ; Hai-rong ZHENG ; Hai-xia DANG ; Qin HU ; Shuai KANG ; Zhong DAI ; Shuang-cheng MA
Acta Pharmaceutica Sinica 2019;54(11):2074-2082
We determined a component-target-disease network for
7.Shenzhu Guanxin Recipe Granules () for Improving Exercise Tolerance in Patients with Stable Angina (SERIES Trial): A Protocol of Multicenter, Randomized, Double-Blind, Placebo Parallel Controlled Clinical Trial.
Shuai MAO ; Dan-Ping XU ; Xiao-Jing DANG ; Winny LI ; Huan-Lin WU
Chinese journal of integrative medicine 2019;25(2):96-102
BACKGROUND:
Many patients with chronic angina experience anginal episodes despite successful recanalization, antianginal and antiischemic medications. Empirical observations suggested that Shenzhu Guanxin Recipe Granules (, SGR), a Chinese herbal compound, exerted potential impacts on increased treadmill exercise performance and angina relieve. However, there has been no systematic study to clarify the impact of SGR on exercise tolerance in patients with stable angina. The SERIES (ShEnzhu guanxin Recipe for Improving Exercise tolerance in patients with Stable angina) trial is designed to determine the effects of SGR on exercise duration, electrocardiographic (ECG) evidence of myocardial ischemia, and incidence of major adverse cardiac events (MACE) in stable anginal patients.
METHODS:
A total of 184 eligible patients with stable angina will be randomly assigned to receive placebo or SGR (10 g/day for 12 weeks) in a 1:1 ratio. The primary outcome will be the change from baseline in total exercise tolerance duration, time to onset of angina and ECG ischemia during exercise treadmill testing performed over a 12-week study period. The secondary outcome will include ECG measures, the occurrence and composite of MACE and the Seattle Angina Questionnaire score. Moreover, the coronary microcirculation will be evaluated to explore the possible effects in response to treatment of SGR. After the procedure, all participants will be followed up by interview at 3 and 6 months, enquiring about any cardiac events, hospitalizations, cardiac functional level and medication usage. Additionally, the occurrence of adverse events will be evaluated at each follow-up.
DISCUSSION
This study may provide novel evidence on the efficacy of SGR in improving exercise tolerance and potentially reducing clinical adverse events. (Trial registration No. ChiCTR-TRC-14004504).
Angina, Stable
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drug therapy
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physiopathology
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Coronary Circulation
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Double-Blind Method
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Drugs, Chinese Herbal
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adverse effects
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therapeutic use
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Exercise Test
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Exercise Tolerance
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physiology
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Humans
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Placebos
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Sample Size
8.Changes of estrogen and its receptor ERα, ERβ and GPR30 in asymptomatic hyperuricemia
Menglan LI ; Wantai DANG ; Xiaoshuang YIN ; Xinyi HE ; Hongbing SUN ; Tianhong LI ; Jing YANG ; Jingguo ZHOU ; Shiquan SHUAI
Chinese Journal of Rheumatology 2018;22(8):537-542
Objective To investigate the changes aad possible role of estrogen and its receptor ERα、ERβ、GPR30 in the pathogenesis of asymptomatic hyperuricemia.Methods The peripheral blood of 62 asymptomatic hyperuricemia patients (AH) and 68 healthy controls (HC) were collected.The expression of estradial (E2) in serum was detected by the chemilluminescent microparticle immunoassay (CMIA).The expression of ERα,ERβ,GPR30 mRNA in peripheral blood mononuclear cells (PBMCs) was measured using Real time quantitative polymerase chain reaction (RT-qPCR).Statistical Package form Soci-science (SPSS) 17.0 statistical software was used for data analysis.The measurement data were compared by t test,rank sum test or one factor analysis of variance test.The correlation between variables was used by Spearman correlation analysis.Results ① The expression of E2 in serum of the HC group was higher than that in the AH group [(38.7±10.2) pg/ml vs (33.7±8.6) pg/ml,Z=-0.356,P<0.05].② The expression of ERα,GPR30 mRNA in PBMCs of HC group was increased,compared with that in the AH group (0.000 17±0.000 23 vs 0.000 12± 0.000 12,0.002 0±0.002 1 vs 0.001 5±0.000 8,Z=-2.112,-2.147,P<0.05,respectively).No significant difference in PBMCs ERβ mRNA levels was found between HC group and AH group,while a slight but not significant increase was observed in HC group.③ The Spearman correlation analysis found that the expression of ERα and ERβ mRNA,E2 and GR,ERβ and GLU in the AH group were positively related (r=0.259,0.251,0.260,P<0.05,respectively).Conclusion The expression of E2,ERα,ERβ,GPR30 mRNA in the peripheral blood of patients with AH is decreased,suggesting that the estrogen and its receptor may be involved in the patho-genesis of hyperuricemia.
9.TIM-1 acts a dual-attachment receptor for Ebolavirus by interacting directly with viral GP and the PS on the viral envelope.
Shuai YUAN ; Lei CAO ; Hui LING ; Minghao DANG ; Yao SUN ; Xuyuan ZHANG ; Yutao CHEN ; Liguo ZHANG ; Dan SU ; Xiangxi WANG ; Zihe RAO
Protein & Cell 2015;6(11):814-824
Ebolavirus can cause hemorrhagic fever in humans with a mortality rate of 50%-90%. Currently, no approved vaccines and antiviral therapies are available. Human TIM1 is considered as an attachment factor for EBOV, enhancing viral infection through interaction with PS located on the viral envelope. However, reasons underlying the preferable usage of hTIM-1, but not other PS binding receptors by filovirus, remain unknown. We firstly demonstrated a direct interaction between hTIM-1 and EBOV GP in vitro and determined the crystal structures of the Ig V domains of hTIM-1 and hTIM-4. The binding region in hTIM-1 to EBOV GP was mapped by chimeras and mutation assays, which were designed based on structural analysis. Pseudovirion infection assays performed using hTIM-1 and its homologs as well as point mutants verified the location of the GP binding site and the importance of EBOV GP-hTIM-1 interaction in EBOV cellular entry.
Ebolavirus
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metabolism
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Flow Cytometry
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Glycoproteins
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metabolism
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Hepatitis A Virus Cellular Receptor 1
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Hepatitis A Virus Cellular Receptor 2
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Humans
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Membrane Glycoproteins
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metabolism
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Membrane Proteins
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metabolism
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Protein Binding
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Receptors, Virus
;
metabolism
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Surface Plasmon Resonance
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Viral Envelope Proteins
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metabolism
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Viral Proteins
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metabolism
10.An open conformation determined by a structural switch for 2A protease from coxsackievirus A16.
Yao SUN ; Xiangxi WANG ; Shuai YUAN ; Minghao DANG ; Xuemei LI ; Xuejun C ZHANG ; Zihe RAO
Protein & Cell 2013;4(10):782-792
Coxsackievirus A16 belongs to the family Picornaviridae, and is a major agent of hand-foot-and-mouth disease that infects mostly children, and to date no vaccines or antiviral therapies are available. 2A protease of enterovirus is a nonstructural protein and possesses both self-cleavage activity and the ability to cleave the eukaryotic translation initiation factor 4G. Here we present the crystal structure of coxsackievirus A16 2A protease, which interestingly forms hexamers in crystal as well as in solution. This structure shows an open conformation, with its active site accessible, ready for substrate binding and cleavage activity. In conjunction with a previously reported "closed" state structure of human rhinovirus 2, we were able to develop a detailed hypothesis for the conformational conversion triggered by two "switcher" residues Glu88 and Tyr89 located within the bll2-cII loop. Substrate recognition assays revealed that amino acid residues P1', P2 and P4 are essential for substrate specificity, which was verified by our substrate binding model. In addition, we compared the in vitro cleavage efficiency of 2A proteases from coxsackievirus A16 and enterovirus 71 upon the same substrates by fluorescence resonance energy transfer (FRET), and observed higher protease activity of enterovirus 71 compared to that of coxsackievirus A16. In conclusion, our study shows an open conformation of coxsackievirus A16 2A protease and the underlying mechanisms for conformational conversion and substrate specificity. These new insights should facilitate the future rational design of efficient 2A protease inhibitors.
Coxsackievirus Infections
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virology
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Crystallography, X-Ray
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Cysteine Endopeptidases
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chemistry
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genetics
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Fluorescence Resonance Energy Transfer
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Hand, Foot and Mouth Disease
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enzymology
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pathology
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virology
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Humans
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Picornaviridae
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chemistry
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enzymology
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genetics
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Protein Conformation
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Structure-Activity Relationship
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Substrate Specificity
;
Viral Proteins
;
chemistry
;
genetics

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