[Research on applying genetic and environmental risk score in risk-adapted colorectal cancer screening]

Objective: To evaluate the effectiveness of a risk-adapted colorectal cancer screening strategy constructed utilizing genetic and environmental risk score (ERS). Methods: A polygenic risk score (PRS) was constructed based on 20 previously published single nucleotide polymorphisms for colorectal cancer in East Asian populations, using 2 160 samples with MassARRAY test results from a multicenter randomized controlled trial of colorectal cancer screening in China. The ERS was calculated using the Asia-Pacific Colorectal Screening Score system. Logistic regression was used to analyze the association between PRS alone and PRS combined with ERS and colorectal neoplasms risk, respectively. We also designed a risk-adapted screening strategy based on PRS and ERS (high-risk participants undergo a single colonoscopy, low-risk participants undergo an annual fecal immunochemical test, and those with positive results undergo further diagnostic colonoscopy) and compared its effectiveness with the all-acceptance colonoscopy strategy. Results: The high PRS group had a 26% increased risk of colorectal neoplasms compared with the low PRS group (OR=1.26, 95%CI: 1.03-1.54, P=0.026). Participants with the highest PRS and ERS were 3.03 times more likely to develop advanced colorectal neoplasms than those with the lowest score (95%CI: 1.87-4.90, P<0.001). As the risk-adapted screening simulation reached the third round, the detection rate of the PRS combined with ERS strategy was not statistically different from the all-acceptance colonoscopy strategy (8.79% vs. 10.46%, P=0.075) and had a higher positive predictive value (14.11% vs. 10.46%, P<0.001) and lower number of colonoscopies per advanced neoplasms detected (7.1 vs. 9.6, P<0.001). Conclusion: The risk-adapted screening strategy combining PRS and ERS helps achieve population risk stratification and better effectiveness than the traditional colonoscopy-based screening strategy.

Src family kinases engage differential pathways for encapsulation into extracellular vesicles

Extracellular vesicles (EVs) are heterogeneous biological nanoparticles secreted by all cell types. Identifying the proteins preferentially encapsulated in secreted EVs will help understand their heterogeneity. Src family kinases including Src and Fyn are a group of tyrosine kinases with fatty acylation modifications and/or multiple lysine residues (contributing charge interaction) at their N-terminus. Here, we demonstrate that Src and Fyn kinases were preferentially encapsulated in EVs and fatty acylation including myristoylation and palmitoylation facilitated their encapsulation. Genetic loss or pharmacological inhibition of myristoylation suppressed Src and/or Fyn kinase levels in EVs. Similarly, loss of palmitoylation reduced Fyn levels in EVs. Additionally, mutation of lysine at sites 5, 7, and 9 of Src kinase also inhibited the encapsulation of myristoylated Src into EVs. Knockdown of TSG101, which is a protein involved in the endosomal sorting complexes required for transport (ESCRT) protein complex mediated EVs biogenesis and led to a reduction of Src levels in EVs. In contrast, filipin III treatment, which disturbed the lipid raft structure, reduced Fyn kinase levels, but not Src kinase levels in EVs. Finally, elevated levels of Src protein were detected in the serum EVs of host mice carrying constitutively active Src-mediated prostate tumors in vivo. Collectively, the data suggest that different EVs biogenesis pathways exist and can regulate the encapsulation of specific proteins into EVs. This study provides an understanding of the EVs heterogeneity created by different EVs biogenesis pathways.

Modelling interventions and contact networks to reduce the spread of carbapenem-resistant organisms between individuals in the ICU

BACKGROUND

Contact precautions are widely used to prevent the transmission of carbapenem-resistant organisms (CROs) in hospital wards. However, evidence for their effectiveness in natural hospital environments is limited.

OBJECTIVE

To determine which contact precautions, healthcare worker (HCW)-patient interactions, and patient and ward characteristics are associated with greater risk of CRO infection or colonization.

DESIGN, SETTING AND PARTICIPANTS

CRO clinical and surveillance cultures from two high-acuity wards were assessed through probabilistic modelling to characterize a susceptible patient's risk of CRO infection or colonization during a ward stay. User- and time-stamped electronic health records were used to build HCW-mediated contact networks between patients. Probabilistic models were adjusted for patient (e.g. antibiotic administration) and ward (e.g. hand hygiene compliance, environmental cleaning) characteristics. The effects of risk factors were assessed by adjusted odds ratio (aOR) and 95% Bayesian credible intervals (CrI).

EXPOSURES

The degree of interaction with CRO-positive patients, stratified by whether CRO-positive patients were on contact precautions.

MAIN OUTCOMES AND MEASURES

The prevalence of CROs and number of new carriers (i.e. incident CRO aquisition).

RESULTS

Among 2193 ward visits, 126 (5.8%) patients became colonized or infected with CROs. Susceptible patients had 4.8 daily interactions with CRO-positive individuals on contact precautions (vs 1.9 interactions with those not on contact precautions). The use of contact precautions for CRO-positive patients was associated with a reduced rate (7.4 vs 93.5 per 1000 patient-days at risk) and odds (aOR 0.03, 95% CrI 0.01-0.17) of CRO acquisition among susceptible patients, resulting in an estimated absolute risk reduction of 9.0% (95% CrI 7.6-9.2%). Also, carbapenem administration to susceptible patients was associated with increased odds of CRO acquisition (aOR 2.38, 95% CrI 1.70-3.29).

CONCLUSIONS AND RELEVANCE

In this population-based cohort study, the use of contact precautions for patients colonized or infected with CROs was associated with lower risk of CRO acquisition among susceptible patients, even after adjusting for antibiotic exposure. Further studies that include organism genotyping are needed to confirm these findings.

Unravelling the Impact of Cyclic Mechanical Stretch in Keratoconus-A Transcriptomic Profiling Study

Biomechanical and molecular stresses may contribute to the pathogenesis of keratoconus (KC). We aimed to profile the transcriptomic changes in healthy primary human corneal (HCF) and KC-derived cells (HKC) combined with TGFβ1 treatment and cyclic mechanical stretch (CMS), mimicking the pathophysiological condition in KC. HCFs (n = 4) and HKCs (n = 4) were cultured in flexible-bottom collagen-coated 6-well plates treated with 0, 5, and 10 ng/mL of TGFβ1 with or without 15% CMS (1 cycle/s, 24 h) using a computer-controlled Flexcell FX-6000T Tension system. We used stranded total RNA-Seq to profile expression changes in 48 HCF/HKC samples (100 bp PE, 70-90 million reads per sample), followed by bioinformatics analysis using an established pipeline with Partek Flow software. A multi-factor ANOVA model, including KC, TGFβ1 treatment, and CMS, was used to identify differentially expressed genes (DEGs, |fold change| ≥ 1.5, FDR ≤ 0.1, CPM ≥ 10 in ≥1 sample) in HKCs (n = 24) vs. HCFs (n = 24) and those responsive to TGFβ1 and/or CMS. PANTHER classification system and the DAVID bioinformatics resources were used to identify significantly enriched pathways (FDR ≤ 0.05). Using multi-factorial ANOVA analyses, 479 DEGs were identified in HKCs vs. HCFs including TGFβ1 treatment and CMS as cofactors. Among these DEGs, 199 KC-altered genes were responsive to TGFβ1, thirteen were responsive to CMS, and six were responsive to TGFβ1 and CMS. Pathway analyses using PANTHER and DAVID indicated the enrichment of genes involved in numerous KC-relevant functions, including but not limited to degradation of extracellular matrix, inflammatory response, apoptotic processes, WNT signaling, collagen fibril organization, and cytoskeletal structure organization. TGFβ1-responsive KC DEGs were also enriched in these. CMS-responsive KC-altered genes such as OBSCN, CLU, HDAC5, AK4, ITGA10, and F2RL1 were identified. Some KC-altered genes, such as CLU and F2RL1, were identified to be responsive to both TGFβ1 and CMS. For the first time, our multi-factorial RNA-Seq study has identified many KC-relevant genes and pathways in HKCs with TGFβ1 treatment under CMS, suggesting a potential role of TGFβ1 and biomechanical stretch in KC development.

[Concordance between three integrated scores based on prostate biopsy and grade-grouping of radical prostatectomy specimen]

Objective: To analyze three different integrated scoring schemes of prostate biopsy and to compare their concordance with the scoring of radical prostatectomy specimens. Methods: A retrospective analysis of 556 patients with radical prostatectomy performed in Nanjing Drum Tower Hospital, Nanjing, China from 2017 to 2020. In these cases, whole organ sections were performed, the pathological data based on biopsy and radical prostatectomy specimens were summarized, and 3 integrated scores of prostate biopsy were calculated, namely the global score, the highest score and score of the largest volume. Results: Among the 556 patients, 104 cases (18.7%) were classified as WHO/ISUP grade group 1, 227 cases (40.8%) as grade group 2 (3+4=7); 143 cases (25.7%) as grade group 3 (4+3=7); 44 cases (7.9%) as grade group 4 (4+4=8) and 38 cases (6.8%) as grade group 5. Among the three comprehensive scoring methods for prostate cancer biopsy, the consistency of global score was the highest (62.4%). In the correlation analysis, the correlation between the scores of radical specimens and the global scores was highest (R=0.730, P<0.01), while the correlations of the scores based on radical specimens with highest scores and scores of the largest volume based on biopsy were insignificant (R=0.719, P<0.01; R=0.631, P<0.01, respectively). Univariate and multivariate analyses showed tPSA group and the three integrated scores of prostate biopsy were statistically correlated with extraglandular invasion, lymph node metastasis, perineural invasion and biochemical recurrence. Elevated global score was an independent prognostic risk factor for extraglandular invasion and biochemical recurrence in patients; increased serum tPSA was an independent prognostic risk factor for extraglandular invasion; increased hjighest score was an independent risk factor for perineural invasion. Conclusions: In this study, among the three different integrated scores, the overall score is most likely corresponded to the radical specimen grade group, but there is difference in various subgroup analyses. Integrated score of prostate biopsy can reflect grade group of radical prostatectomy specimens, thereby providing more clinical information for assisting in optimal patient management and consultation.

Electrical Stimulation Increases the Secretion of Cardioprotective Extracellular Vesicles from Cardiac Mesenchymal Stem Cells

Clinical trials have shown that electric stimulation (ELSM) using either cardiac resynchronization therapy (CRT) or cardiac contractility modulation (CCM) approaches is an effective treatment for patients with moderate to severe heart failure, but the mechanisms are incompletely understood. Extracellular vesicles (EV) produced by cardiac mesenchymal stem cells (C-MSC) have been reported to be cardioprotective through cell-to-cell communication. In this study, we investigated the effects of ELSM stimulation on EV secretion from C-MSCs (C-MSCELSM). We observed enhanced EV-dependent cardioprotection conferred by conditioned medium (CM) from C-MSCELSM compared to that from non-stimulated control C-MSC (C-MSCCtrl). To investigate the mechanisms of ELSM-stimulated EV secretion, we examined the protein levels of neutral sphingomyelinase 2 (nSMase2), a key enzyme of the endosomal sorting complex required for EV biosynthesis. We detected a time-dependent increase in nSMase2 protein levels in C-MSCELSM compared to C-MSCCtrl. Knockdown of nSMase2 in C-MSC by siRNA significantly reduced EV secretion in C-MSCELSM and attenuated the cardioprotective effect of CM from C-MSCELSM in HL-1 cells. Taken together, our results suggest that ELSM-mediated increases in EV secretion from C-MSC enhance the cardioprotective effects of C-MSC through an EV-dependent mechanism involving nSMase2.

[Effect of low density carotid plaque on the development of cerebral small vessel disease in patients with carotid stenosis]

Objective: To investigate the correlation between cerebral small vessel disease (CSVD) and carotid low-density plaque on multi-slice spiral CT angiography (MSCTA) in patient with carotid stenosis. Methods: The clinical data of 221 patients with carotid stenosis who admitted to Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School, from January 2016 to January 2021 were retrospectively analyzed. There were 195 males and 26 females, with the age of (70.0±8.4) years (range: 48 to 88 years). According to MRI, the patients were divided into carotid stenosis combined with CSVD group (the CSVD group) and carotid stenosis without CSVD group (the non-CSVD group). Lowest density in the carotid atherosclerotic plaque area (CAPALD) was analyzed by MSCTA. The t-test, Mann-Whitney U test and Chi-square test were used for comparison between the two groups. Univariate and multivariate Logistic regression analysis were performed on CAPALD and other clinical indicators with CSVD. Receiver operating characteristic (ROC) curves of CAPALD and CAPALD combined with the demographics (sex, age and body mass index) were plotted for predicting CSVD, and the area under the curve (AUC), sensitivity and specificity were calculated. Results: There were 169 patients in the CSVD group and 52 patients in the non-CSVD group. In the CSVD group, 88.8% (150/169) were males and 11.2% (19/169) were females, with the age of (70.5±8.2) years (range: 48 to 88 years). In the non-CSVD group, 86.5% (45/52) were males and 13.5% (7/52) were females, with the age of (68.4±9.1) years (range: 51 to 85 years). CAPALD and the score of Montreal cognitive assessment were lower in the CSVD group than those in the non-CSVD group (21.0 HU vs. 35.0 HU, Z=-3.760, P<0.01; 22.6±3.9 vs. 24.8±3.3, t=-2.064, P<0.05). Multivariate Logistic regression analysis showed that CAPALD was an independent factor for CSVD (OR=1.044, 95%CI:1.020 to 1.070, P<0.01). The AUC of the ROC curve for CAPALD predicting carotid stenosis with CSVD was 0.672 (P<0.01), with cut-off value of 34.5 HU, sensitivity of 82.8%, and specificity of 50.0%. The AUC of ROC curve for CAPALD combined with the demographics predicting CSVD was 0.733 (P<0.01), with sensitivity of 82.9% and specificity of 64.0%. Conclusions: The decreased CAPALD is a risk factor for CSVD in patients with carotid stenosis. The analysis of carotid plaque density by MSCTA may help to identify the patients at high risk of CSVD.

The Value of Preoperative Phase-Contrast MRI in Predicting the Clinical Outcome of Moyamoya Disease after Encephalo-Duro-Arterial Synangiosis Surgery

BACKGROUND AND PURPOSE

In patients with Moyamoya disease, the relationship between preoperative hemodynamic status and prognosis after encephalo-duro-arterial synangiosis (EDAS) surgery was unclear. We aimed to explore the value of the preoperative hemodynamic status acquired by cine phase-contrast MR imaging in predicting collateral formation and clinical outcomes after EDAS surgery in patients with Moyamoya disease.

MATERIALS AND METHODS

Participants with Moyamoya disease were prospectively recruited and underwent preoperative phase-contrast MR imaging. All participants were classified into good and poor groups according to the collateral formation after EDAS surgery. On the basis of the change in the mRS system, participants were classified into the improved mRS group and the poor response group. Hemodynamic status including mean velocity, peak velocity, and blood volume flow of the superficial temporal artery was compared between groups. Logistic regression was performed to relate the phase-contrast MR imaging parameters to collateral formation and clinical outcomes.

RESULTS

A total of 45 patients with Moyamoya disease with unilateral EDAS surgery were finally included. Mean velocity, peak velocity, and blood volume flow of the ipsilateral superficial temporal artery were significantly greater in patients with good collateral formation compared with those with poor collateral formation (P = .011, .004, and .013, respectively). The mean velocity, peak velocity, and blood volume flow were independently associated with postoperative collateral formation after adjusting for confounding factors. Furthermore, the peak velocity of the ipsilateral superficial temporal artery was also significantly associated with improvement of the mRS score.

CONCLUSIONS

Good hemodynamic status of the ipsilateral superficial temporal artery as a donor artery evaluated by phase-contrast MR imaging was significantly associated with better collateral formation and improved mRS after EDAS surgery in patients with Moyamoya disease.

Wien effect in interfacial water dissociation through proton-permeable graphene electrodes

Strong electric fields can accelerate molecular dissociation reactions. The phenomenon known as the Wien effect was previously observed using high-voltage electrolysis cells that produced fields of about 10⁷ V m^-1, sufficient to accelerate the dissociation of weakly bound molecules (e.g., organics and weak electrolytes). The observation of the Wien effect for the common case of water dissociation (H₂O [Formula: see text] H⁺ + OH^-) has remained elusive. Here we study the dissociation of interfacial water adjacent to proton-permeable graphene electrodes and observe strong acceleration of the reaction in fields reaching above 10⁸ V m^-1. The use of graphene electrodes allows measuring the proton currents arising exclusively from the dissociation of interfacial water, while the electric field driving the reaction is monitored through the carrier density induced in graphene by the same field. The observed exponential increase in proton currents is in quantitative agreement with Onsager's theory. Our results also demonstrate that graphene electrodes can be valuable for the investigation of various interfacial phenomena involving proton transport.

Analysis results of 169 cases of chorionic villus samples of missed abortion using high throughput sequencing

OBJECTIVE

This study aimed to evaluate the use of high-throughput sequencing (HTS) technology to detect chromosomes in chorionic villus samples of missed abortion embryos and investigate its utility in the genetic diagnosis of missed abortion.

PATIENTS AND METHODS

HTS was used to assess chorionic villus samples obtained from 169 patients with missed abortions from August 2020 to March 2022, at the Second Affiliated Hospital of Guangxi Medical University. The test results were statistically analyzed. To investigate the impact of advanced age on the incidence of chromosomal abnormalities, the patients were divided into two groups: elderly (≥35 years) and nonelderly pregnant women (<35 years).

RESULTS

(1) Among the samples of 169 patients, 100 (59.17%) cases of chromosomal abnormalities were detected. Among these 100, 90 (90%) had chromosomal numerical abnormalities and 10 (10%) had chromosomal structural abnormalities. (2) Chromosomal numerical abnormality was abnormalities mainly included aneuploidy (92.22%, 83/90), with trisomy (62.22%, 56/90) and monosomy (22.22%, 20/90) accounting for the majority. The top three numerical abnormalities included 18 cases of Turner syndrome (monosomy X; 20%, 18/90), 10 cases of trisomy 16 (11.11%, 10/90), and 10 cases of trisomy 22 (11.11%, 10/90). (3) Villous chromosomal abnormalities were found in 48 (70.59%) elderly pregnant women, and 52 (51.48%) nonelderly pregnant women, with statistically significant differences (p < 0.05).

CONCLUSIONS

(1) Chromosomal abnormality is an important cause of missed abortion, it majorly includes chromosomal numerical abnormality, of which most cases are of aneuploidy. (2) Advanced age may increase the risk of embryonic chromosomal abnormalities. (3) Villus chromosome detection using HTS has a positive value and can be used for analyzing and determining the causes of missed abortion.

Use of a urinary catheter as a guidewire to facilitate safe nasotracheal intubation following iatrogenic retropharyngeal perforation

Nasotracheal intubation facilitates adequate access for surgical procedures in the oral cavity, is not limited by mouth opening and can be better tolerated by patients in intensive care. Complications of nasotracheal intubation can include epistaxis, turbinate injury and sinusitis. Retropharyngeal submucosal perforation by the tracheal tube has also been infrequently reported. Here, we report a case of difficult nasotracheal intubation resulting in retropharyngeal submucosal perforation in a patient with a history of obstructive sleep apnoea listed for uvulopalatopharyngoplasty. To facilitate successful tracheal re-intubation, we used a soft urinary catheter via the other nostril. In this report, we discuss the reasons why this complication may have occurred, how submucosal perforation could be avoided, and reflect on our management of this rare complication. Difficult nasotracheal intubation can present unique challenges, and airway management plans should be made accordingly.

[Analysis of perioperative efficacy and safety of cytoreductive surgery in the treatment of colorectal cancer peritoneal metastases]

Objective: To analyzed perioperative safety of cytoreductive surgery (CRS) for patients with colorectal cancer peritoneal metastasis (CRPM) and to construct a predictive model for serious advese events (SAE). Methods: A descriptive case-series study was conducted to retrospectively collect the clinicopathological data and treatment status (operation time, number of organ resection, number of peritoneal resection, and blood loss, etc.) of 100 patients with peritoneal metastases from colorectal cancer or appendix mucinous adenocarcinoma who underwent CRS at the Sixth Affiliated Hospital of Sun Yat-sen University from January 2019 to August 2021. There were 53 males and 47 females. The median age was 52.0 (39.0-61.8) years old. Fifty-two patients had synchronous peritoneal metastasis and 48 had metachronous peritoneal metastasis. Fifty-two patients received preoperative neoadjuvant therapy. Primary tumor was located in the left colon, the right colon and the rectum in 43, 28 and 14 cases, respectively. Fifteen patients had appendix mucinous adenocarcinoma. Measures of skewed distribution are expressed as M (range). Perioperative safety was analyzed, perioperative grade III or higher was defined as SAE. Risk factors associated with the occurrence of SAEs were analyzed using multivariate logistic regression. A nomogram was plotted by R software to predict SAE, the efficacy of which was evaluated using the area under the ROC curve (AUC) and correction curves. Results: The median peritoneal cancer index (PCI) score was 16 (1-39). Sixty-eight (68.0%) patients achieved complete tumor reduction (tumor reduction score: 0-1). Sixty-two patients were treated with intraperitoneal hyperthermic perfusion chemotherapy (HIPEC). Twenty-one (21.0%) patients developed 37 SAEs of grade III-IV, including 2 cases of ureteral injury, 6 cases of perioperative massive hemorrhage or anemia, 7 cases of digestive system, 15 cases of respiratory system, 4 cases of cardiovascular system, 1 case of skin incision dehiscence, and 2 cases of abdominal infection. No grade V SAE was found. Multivariate logistic regression analysis showed that CEA (OR: 8.980, 95%CI: 1.428-56.457, P=0.019), PCI score (OR: 7.924, 95%CI: 1.486-42.259, P=0.015), intraoperative albumin infusion (OR: 48.959, 95%CI: 2.115-1133.289, P=0.015) and total volume of infusion (OR: 24.729, 95%CI: 3.956-154.562, P=0.001) were independent risk factors for perioperative SAE in CRS (all P<0.05). Based on the result of multivariate regression models, a predictive nomogram was constructed. Internal verification showed that the AUC of the nomogram was 0.926 (95%CI: 0.872-0.980), indicating good prediction accuracy and consistency. Conclusions: CRS is a safe and effective method to treat CRPM. Strict screening of patients and perioperative fluid management are important guarantees for reducing the morbidity of SAE.

Effects of functional mandibular lateral shift on craniofacial growth and development in growing rats

BACKGROUND

Unilateral posterior crossbite, one of the most frequent malocclusions, is often associated with functional lateral shift of the mandible. Although the effects of functional lateral shift on the mandible and temporomandibular joint have been examined in various animal experiments, cranial and maxillary changes have received less attention.

OBJECTIVE

This study investigated the effects of functional lateral shift on the craniofacial complex in growing rats.

METHODS

Eighty 5-week-old male Sprague-Dawley rats were randomly. divided into an experimental group (n=40), which received an oblique guide appliance that shifted the mandible to the left during closure, and a control group (n=40). The rats were scanned by cone-beam computed tomography at 3 days and 1, 2, 4, and 8 weeks. The dimensions of the mandibular bone, condyle, maxilla and cranium were measured.

RESULTS

The mandibles of rats in the experimental group were smaller than those of the rats in the control group and were asymmetrical. The condyles of the rats in the experimental group were thinner than those of the control rats. The condylar length on the ipsilateral side was shorter and wider than that on the contralateral side from 4 to 8 weeks. No significant differences in cranial length or height were observed between the experimental and control groups. The height of the upper first molar and alveolar bone on the contralateral side was significantly smaller than that on the ipsilateral side and in the controls from 4 to 8 weeks.

CONCLUSION

Functional shift in the mandible produces morphological asymmetries in the mandible and maxillary region and may cause bilateral condylar degenerative changes.

Oral submucous fibrosis induced by graft-versus-host disease after allogeneic hematopoietic stem cell transplantation

Graft-versus-host disease (GVHD) is one of the most common and serious complications after allogeneic hematopoietic stem cell transplantation (allo-HSCT). About 45%∼83% of patients develop GVHD in the oral cavity. There has no medical records of oral submucous fibrosis (OSF) induced by GVHD after allo-HSCT, which should be brought to the attention of dentists.

Explore the Mechanism of β-Asarone on Improving Cognitive Dysfunction in Rats with Diabetic Encephalopathy

Background: The number of people with diabetes is increasing, and many patients have significantly impaired cognitive function. For patients with diabetic encephalopathy (DE), simply lowering blood sugar does not improve learning and memory. Studies have shown that β-asarone can significantly improve cognitive impairment in patients with DE, but the specific mechanism of action is unclear. Objective: This experiment hopes to use a variety of experimental methods to clarify the protective effect and mechanism of β-asarone on brain neurons during the development of DE disease. Methods: A high-sugar and high-fat diet and streptozotocin injection-induced DE rat model was used. β-asarone was administered for four weeks. The experiment used the Morris water maze test, biochemical index detection, and many methods to evaluate the neuroprotective effect of β-asarone on DE rats from various aspects and understand its mechanism. Results: β-asarone reduced neuronal cell damage and significantly improved the learning and memory ability of DE rats. In addition, β-asarone can reduce the oxidative stress response and amyloid-β accumulation in the brain of DE model rats and increase the content of brain-derived neurotrophic factor (BDNF) in the brain tissue, thereby reducing neuronal cell apoptosis and playing a protective role. Conclusion: β-asarone can reduce the accumulation of oxidative stress and amyloid-β in the brain, increase the content of BDNF, reduce the apoptosis of neuronal cells, and exert neuronal protection, thereby improving the learning and memory ability of DE model rats.

Encapsulating Cas9 into extracellular vesicles by protein myristoylation

CRISPR/Cas9 genome editing is a very promising avenue for the treatment of a variety of genetic diseases. However, it is still very challenging to encapsulate CRISPR/Cas9 machinery for delivery. Protein N-myristoylation is an irreversible co/post-translational modification that results in the covalent attachment of the myristoyl-group to the N-terminus of a target protein. It serves as an anchor for a protein to associate with the cell membrane and determines its intracellular trafficking and activity. Extracellular vesicles (EVs) are secreted vesicles that mediate cell-cell communication. In this study, we demonstrate that myristoylated proteins were preferentially encapsulated into EVs. The octapeptide derived from the leading sequence of the N-terminus of Src kinase was a favourable substrate for N-myristoyltransferase 1, the enzyme that catalyzes myristoylation. The fusion of the octapeptide onto the N-terminus of Cas9 promoted the myristoylation and encapsulation of Cas9 into EVs. Encapsulation of Cas9 and sgRNA-eGFP inside EVs was confirmed using protease digestion assays. Additionally, to increase the transfection potential, VSV-G was introduced into the EVs. The encapsulated Cas9 in EVs accounted for 0.7% of total EV protein. Importantly, the EVs coated with VSV-G encapsulating Cas9/sgRNA-eGFP showed up to 42% eGFP knock out efficiency with limited off-target effects in recipient cells. Our study provides a novel approach to encapsulate CRISPR/Cas9 protein and sgRNA into EVs. This strategy may open an effective avenue to utilize EVs as vehicles to deliver CRISPR/Cas9 for genome-editing-based gene therapy.