An atlas of dynamic chromatin landscapes in mouse fetal development.

The Encyclopedia of DNA Elements (ENCODE) project has established a genomic resource for mammalian development, profiling a diverse panel of mouse tissues at 8 developmental stages from 10.5 days after conception until birth, including transcriptomes, methylomes and chromatin states. Here we systematically examined the state and accessibility of chromatin in the developing mouse fetus. In total we performed 1,128 chromatin immunoprecipitation with sequencing (ChIP-seq) assays for histone modifications and 132 assay for transposase-accessible chromatin using sequencing (ATAC-seq) assays for chromatin accessibility across 72 distinct tissue-stages. We used integrative analysis to develop a unified set of chromatin state annotations, infer the identities of dynamic enhancers and key transcriptional regulators, and characterize the relationship between chromatin state and accessibility during developmental gene regulation. We also leveraged these data to link enhancers to putative target genes and demonstrate tissue-specific enrichments of sequence variants associated with disease in humans. The mouse ENCODE data sets provide a compendium of resources for biomedical researchers and achieve, to our knowledge, the most comprehensive view of chromatin dynamics during mammalian fetal development to date.

Author Correction: An atlas of dynamic chromatin landscapes in mouse fetal development.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

STMHCpan, an accurate Star-Transformer-based extensible framework for predicting MHC I allele binding peptides.

Peptide-major histocompatibility complex I (MHC I) binding affinity prediction is crucial for vaccine development, but existing methods face limitations such as small datasets, model overfitting due to excessive parameters and suboptimal performance. Here, we present STMHCPan (STAR-MHCPan), an open-source package based on the Star-Transformer model, for MHC I binding peptide prediction. Our approach introduces an attention mechanism to improve the deep learning network architecture and performance in antigen prediction. Compared with classical deep learning algorithms, STMHCPan exhibits improved performance with fewer parameters in receptor affinity training. Furthermore, STMHCPan outperforms existing ligand benchmark datasets identified by mass spectrometry. It can also handle peptides of arbitrary length and is highly scalable for predicting T-cell responses. Our software is freely available for use, training and extension through Github (https://github.com/Luckysoutheast/STMHCPan.git).

Deciphering the molecular and functional basis of TMexCD1: the plasmid-encoded efflux pump of resistance-nodulation-division superfamily.

Horizontal gene transfer has been demonstrated to be an important driver for the emergency of multidrug-resistant pathogens. Recently, a transferable gene cluster tmexCD1-toprJ1 of the resistance-nodulation-division (RND) superfamily was identified in the plasmids of animal-derived Klebsiella pneumoniae strains, with a higher efflux capacity for various drugs than the Escherichia coli AcrAB-TolC homolog system. In this study, we focused on the differences in the inner membrane pump of these two systems and identified some key residues that contribute to the robust efflux activity of the TMexCD1 system. With the aid of homologous modeling and molecular docking, eight residues from the proximal binding pocket (PBP) and nine from the distal binding pocket (DBP) were selected and subjected to site-directed mutagenesis. Several of them, such as S134, I139, D181, and A290, were shown to be important for substrate binding in the DBP region, and all residues in PBP and DBP showed certain substrate preferences. Apart from the conservative switch loop (L613-623TMexD1) previously identified in the E. coli AcrB (EcAcrB), a relatively unconservative loop (L665-675TMexD1) at the bottom of PBP was proposed as a critical element for the robust activity of TMexD1, due to variations at sites E669, G670, N673, and S674 compared to EcAcrAB, and the significantly altered efflux activity due to their mutations. The conservation and flexibility of these key factors can contribute to the evolution of the RND efflux pumps and thus serve as potential targets for developing inhibitors to block the widespread of the TMexCD1 system.

Cross-talk of pyroptosis-based subtypes, the development of a risk classifier and immune responses in cervical cancer.

BACKGROUND: Cervical cancer (CC) is one of the most common gynecology malignancies and has a dismal survival outcome. The prognostic value of pyroptosis and its role in the regulation of immune metabolism in CC remain unclear. METHODS: Two independent CC cohorts collected from public databases were integrated for unsupervised cluster analysis. All CC cases were assigned to different subsets based on the pyroptosis-related genes (PRGs). The differentially expressed genes (DEGs) between different subclusters were included in stepwise Cox regression for the risk classifier establishment. Next, single-cell sequencing analysis was conducted to explore the cellular location of each model gene. The CIBERSORT algorithm was applied to estimate immunocytes infiltration. Finally, a series of functional experiments were performed to detect the role of CDH3 in CC. RESULTS: Based on the 52 PRGs, the combined CC cohort was clustered into two subsets (C1 (n = 259) and C2 (n = 242)). Survival and Cox regression methods were used to create a pyroptosis-based risk classifier including four PRGs (PEG3, FSCN1, CDH3 and SLC2A1). For the immune environment in CC, the high-risk group had a lower infiltration level of B cells, memory-activated CD4 T cells and CD8 T cells and a higher infiltration abundance of neutrophils. The expression pattern of model genes was confirmed in CC cell lines by PCR assay. Furthermore, we observed that knockdown of CDH3 could suppress CC cell proliferation. CONCLUSION: Our project could offer promising reference for prognosis assessment, immune metabolism prediction and clinical decision-making of patients with CC.

Cancer-associated fibroblast-secreted FGF7 as an ovarian cancer progression promoter.

BACKGROUND: Ovarian cancer (OC) is distinguished by its aggressive nature and the limited efficacy of current treatment strategies. Recent studies have emphasized the significant role of cancer-associated fibroblasts (CAFs) in OC development and progression. METHODS: Employing sophisticated machine learning techniques on bulk transcriptomic datasets, we identified fibroblast growth factor 7 (FGF7), derived from CAFs, as a potential oncogenic factor. We investigated the relationship between FGF7 expression and various clinical parameters. A series of in vitro experiments were undertaken to evaluate the effect of CAFs-derived FGF7 on OC cell activities, such as proliferation, migration, and invasion. Single-cell transcriptomic analysis was also conducted to elucidate the interaction between FGF7 and its receptor. Detailed mechanistic investigations sought to clarify the pathways through which FGF7 fosters OC progression. RESULTS: Our findings indicate that higher FGF7 levels correlate with advanced tumor stages, increased vascular invasion, and poorer prognosis. CAFs-derived FGF7 significantly enhanced OC cell proliferation, migration, and invasion. Single-cell analysis and in vitro studies revealed that CAFs-derived FGF7 inhibits the ubiquitination and degradation of hypoxia-inducible factor 1 alpha (HIF-1α) via FGFR2 interaction. Activation of the FGF7/HIF-1α pathway resulted in the upregulation of mesenchymal markers and downregulation of epithelial markers. Importantly, in vivo treatment with neutralizing antibodies targeting CAFs-derived FGF7 substantially reduced tumor growth. CONCLUSION: Neutralizing FGF7 in the medium or inhibiting HIF-1α signaling reversed the effects of FGF7-mediated EMT, emphasizing the dependence of FGF7-mediated EMT on HIF-1α activation. These findings suggest that targeting the FGF7/HIF-1α/EMT axis may offer new therapeutic opportunities to intervene in OC progression.

Diagnostic accuracy of pancreatic stone protein in patients with sepsis: a systematic review and meta-analysis.

BACKGROUND: Sepsis is a common syndrome of multiorgan system dysfunction secondary to the dysregulated inflammatory response to infection. The role of pancreatic stone protein (PSP) in diagnosing sepsis has been investigated in previous studies. The meta-analysis aimed to comprehensively investigate the diagnostic value of PSP in identifying sepsis. METHODS: PubMed, Web of Science, Embase, Cochrane Library, and China National Knowledge Infrastructure (CNKI), were systematically searched. Studies investigating the diagnostic performance of PSP were included. Pooled sensitivity, specificity, positive Likelihood Ratio (+ LR) and negative Likelihood Ratio (-LR), diagnostic odds ratio (DOR), and area under the curve (AUC) of summary receiver operating characteristic (SROC) were calculated. RESULTS: The sensitivity of PSP was 0.88 (95% CI: 0.77-0.94), and the pooled specificity was 0.78 (95% CI: 0.65-0.87). Pooled + LR, -LR, and DOR were 4.1 (2.3, 7.3), 0.16 (0.07, 0.34), and 26 (7, 98). The AUC value for the SROC of PSP was 0.90 (0.87, 0.92). The pooled sensitivity, specificity, + LR and - LR, and DOR for PSP among neonates were 0.91 (95% CI: 0.84, 0.96), 0.66 (95% CI: 0.58, 0.74), 3.97 (95% CI: 0.53, 29.58), 0.13 (95% CI: 0.02, 1.00), and 31.27 (95% CI: 0.97, 1004.60). CONCLUSIONS: This study indicates that PSP demonstrated favorable diagnostic accuracy in detecting sepsis. Well-designed studies are warranted to ascertain the value of PSP measurement to guide early empirical antibiotic treatment, particularly in neonates.

The relationship between serum creatinine/cystatin C ratio and mortality in hypertensive patients.

BACKGROUND AND AIMS: Sarcopenia is a disease characterized by loss of skeletal muscle mass and function that is closely associated with cardiovascular disease. The serum creatinine/cystatin C (Cr/CysC) ratio has been shown to be a simplified indicator for identifying low muscle mass (LMM) or sarcopenia. The aim of this study was to investigate whether the Cr/CysC ratio helps to predict prognostic information in hypertensive patients. METHODS AND RESULTS: This cohort study included 2509 patients with hypertension from the National Health and Nutrition Survey 1999-2002. To evaluate the association between Cr/CysC ratio and mortality, we used Kaplan Meier estimates to calculate cumulative survival probabilities for all-cause mortality and cardiovascular mortality, Cox regression analyses, and hazard ratio (HR) and 95% confidence interval (CI) were calculated. Over a median follow-up of 11.76 years, lower Cr/CysC ratio was associated with lower risk of all-cause mortality (per 0.1 increase, HR:0.81, 95% CI: 0.77-0.85, P < 0.001) and cardiovascular mortality (per 0.1 increase, HR:0.80, 95% CI: 0.72-0.89, P < 0.001). Compared with patients with normal muscle mass, all-cause mortality, and cardiovascular mortality HR for patients with LMM diagnosed by Cr/CysC ratio were 1.57 (95% CI: 1.36-1.82, P < 0.001) and 1.64 (95% CI: 1.12-2.42, P = 0.012), respectively. CONCLUSION: We found that low muscle mass shown by lower Cr/CysC ratio was an independent risk factor for poor prognosis in hypertensive patients. We recommend routine screening of Cr/CysC ratio in hypertensive patients and early intervention for low muscle mass or sarcopenia.

Regulatory elements can be essential for maintaining broad chromatin organization and cell viability.

Increasing evidence shows that promoters and enhancers could be related to 3D chromatin structure, thus affecting cellular functions. Except for their roles in forming canonical chromatin loops, promoters and enhancers have not been well studied regarding the maintenance of broad chromatin organization. Here, we focused on the active promoters/enhancers predicted to form many 3D contacts with other active promoters/enhancers (referred to as hotspots) and identified dozens of loci essential for cell growth and survival through CRISPR screening. We found that the deletion of an essential hotspot could lead to changes in broad chromatin organization and the expression of distal genes. We showed that the essentiality of hotspots does not result from their association with individual genes that are essential for cell viability but rather from their association with multiple dysregulated non-essential genes to synergistically impact cell fitness.

Deciphering the Glycosylation Steps in the Biosynthesis of P-1894B and Grincamycin Isolated from Marine-Derived Streptomyces lusitanus SCSIO LR32.

Recently, we re-isolated the glycosylated angucycline antibiotics P-1894B (1) and grincamycin (1') from the marine-derived Streptomyces lusitanus SCSIO LR32 as potent antitumor agents and identified their biosynthesis gene cluster gcn. Both P-1894B (1) and grincamycin (1') possess a trisaccharide and a disaccharide moiety comprised of five deoxysugars. In this work, three genes encoding glycosyltransferases (GcnG1, GcnG2, and GcnG3) responsible for the assembly of deoxysugars into angucycline aglycone were identified from the biosynthesis gene cluster gcn. Gene inactivations of gcnG1, gcnG2, gcnG3, and gcnG1G2 by lambda-RED-mediated gene replacements led to the construction of four mutants, in which the glycosyltransferase genes were disrupted, respectively. The metabolites from the mutants were purified and identified, including two new analogues designated as grincamycin U (3a) and V (3'). The sequential glycosylation steps in the biosynthesis of P-1894B (1) and grincamycin (1') catalyzed by GcnG3, GcnG1, and GcnG2 were elucidated.

Comprehensive Analysis of the SUMO-related Signature: Implication for Diagnosis, Prognosis, and Immune Therapeutic Approaches in Cervical Cancer.

SUMOylation, an important post-translational protein modification, plays a critical role in cancer development and immune processes. This study aimed to construct diagnostic and prognostic models for cervical cancer (CC) using SUMOylation-related genes (SRGs) and explore their implications for novel clinical therapies. We analyzed the expression profiles of SRGs in CC patients and identified 15 SRGs associated with CC occurrence. After the subsequent qPCR verification of 20 cases of cancer and adjacent tissues, 13 of the 15 SRGs were differentially expressed in cancer tissues. Additionally, we identified molecular markers associated with the prognosis and recurrence of CC patients, based on SRGs. Next, a SUMOScore, based on SRG expression patterns, was generated to stratify patients into different subgroups. The SUMOScore showed significant associations with the tumor microenvironment, immune function features, immune checkpoint expression, and immune evasion score in CC patients, highlighting the strong connection between SUMOylation factors and immune processes. In terms of immune therapy, our analysis identified specific chemotherapy drugs with higher sensitivity in the subgroups characterized by high and low SUMOScore, indicating potential treatment options. Furthermore, we conducted drug sensitivity analysis to evaluate the response of different patient subgroups to conventional chemotherapy drugs. Our findings revealed enrichment of immune-related pathways in the low-risk subgroup identified by the prognostic model. In conclusion, this study presents diagnostic and prognostic models based on SRGs, accompanied by a comprehensive index derived from SRGs expression patterns. These findings offer valuable insights for CC diagnosis, prognosis, treatment, and immune-related analysis.

Exosomes derived from ovarian cancer cells regulate proliferation and migration of cancer-associated fibroblasts.

Cancer-associated fibroblast (CAF) is an essential risk factor for ovarian cancer. Exosomes can mediate cellular communication in the tumour microenvironment, but the interaction of tumour cell exosomes with CAF is less studied in Ovarian cancer. This study identified H19/miR-29c-3p/LOXL2-COL1A1 as a ceRNA regulatory network involved in regulating tumour matrix-associated signaling pathways associated with CAF. Cellular assays demonstrated that exosomes from ovarian cancer cell line SKOV3 significantly promoted the proliferation and migration of CAF. The results of mixed transplantation tumour experiments in nude mice showed that exosomes of SKOV3 significantly promoted tumour growth. Ovarian cancer tumour-derived exosomes can regulate CAF proliferation and migration through H19/miR-29c-3p/LOXL2-COL1A1. This study reveals the regulatory role of tumour exosomes on CAF, which may provide a theoretical basis for the development of therapeutic regimens targeting fibroblasts in ovarian cancer.

Distraction Osteotomy Combined With Orthodontics: An Effective Way to Decrease Short-term Recurrence in Treating Child Craniofacial Microsomia.

BACKGROUND: This study aims to investigate strategies for reducing early relapse following mandibular distraction osteotomy (MDO) in craniofacial microsomia (CFM) patients. METHODS: Forty CFM patients were divided into 2 groups: 20 underwent MDO alone, while 20 received MDO combined with orthodontic treatment (MDO-O). Preoperative, prefixation, and postfixation CT data in DICOM format were collected and reconstructed using Proplan software. Spatial geometric analysis was conducted to assess the inclination angle of the occlusal plane (OP), and OP deviation was directly measured using the software. RESULTS: Patients in the MDO-O group demonstrated a statistically significant improvement in OP inclination at the end of the fixation period compared with those who underwent MDO alone ( P =0.003). CONCLUSIONS: Combining MDO with a bite plate and bite glue sticks in CFM patients during the mixed dentition period enhances OP outcomes, effectively reducing short-term recurrence.

GhMYB52 Like: A Key Factor That Enhances Lint Yield by Negatively Regulating the Lignin Biosynthesis Pathway in Fibers of Upland Cotton (Gossypium hirsutum L.).

In the context of sustainable agriculture and biomaterial development, understanding and enhancing plant secondary cell wall formation are crucial for improving crop fiber quality and biomass conversion efficiency. This is especially critical for economically important crops like upland cotton (Gossypium hirsutum L.), for which fiber quality and its processing properties are essential. Through comprehensive genome-wide screening and analysis of expression patterns, we identified a particularly high expression of an R2R3 MYB transcription factor, GhMYB52 Like, in the development of the secondary cell wall in cotton fiber cells. Utilizing gene-editing technology to generate a loss-of-function mutant to clarify the role of GhMYB52 Like, we revealed that GhMYB52 Like does not directly contribute to cellulose synthesis in cotton fibers but instead represses a subset of lignin biosynthesis genes, establishing it as a lignin biosynthesis inhibitor. Concurrently, a substantial decrease in the lint index, a critical measure of cotton yield, was noted in parallel with an elevation in lignin levels. This study not only deepens our understanding of the molecular mechanisms underlying cotton fiber development but also offers new perspectives for the molecular improvement of other economically important crops and the enhancement of biomass energy utilization.

Downregulation of the GhROD1 Gene Improves Cotton Fiber Fineness by Decreasing Acyl Pool Saturation, Stimulating Small Heat Shock Proteins (sHSPs), and Reducing H2O2 Production.

Cotton fiber is one of the most important natural fiber sources in the world, and lipid metabolism plays a critical role in its development. However, the specific role of lipid molecules in fiber development and the impact of fatty acid alterations on fiber quality remain largely unknown. In this study, we demonstrate that the downregulation of GhROD1, a gene encoding phosphatidylcholine diacylglycerol cholinephosphotransferase (PDCT), results in an improvement of fiber fineness. We found that GhROD1 downregulation significantly increases the proportion of linoleic acid (18:2) in cotton fibers, which subsequently upregulates genes encoding small heat shock proteins (sHSPs). This, in turn, reduces H2O2 production, thus delaying secondary wall deposition and leading to finer fibers. Our findings reveal how alterations in linoleic acid influence cellulose synthesis and suggest a potential strategy to improve cotton fiber quality by regulating lipid metabolism pathways.

Multifactorial analysis of willingness to undergo subcutaneous allergen immunotherapy in pediatric patients.

Objective: To explore factors influencing the acceptance of allergen immunotherapy (AIT) for the treatment of allergic respiratory diseases by pediatric patients and their families. Methods: A total of 406 children (210 males and 196 females) attending the pediatric outpatient clinics and wards of the Renji Hospital, Shanghai Jiao Tong University School of Medicine from June 2020 to April 2022. Those who met the criteria for the AIT treatment, were included in the survey. An online 20-item questionnaire was developed. Data on patient's general characteristics, allergic disease status, family history of allergies, general family information, parental knowledge of allergic diseases, and whether the AIT treatment was recommended by a physician, were collected. The patients were divided into two groups according to their willingness to receive AIT: a reluctant or neutral group (n = 182), and a willing group (n = 224). A univariate analysis of the willingness to undergo AIT was done to detect parameters that significantly differed between the groups, and the identified factors were used as independent variables in the multifactorial logistic regression analysis. Results: The severity of allergic disease, presence of drug allergy, occurrence of severe allergic reactions, mother's education, distance from home to the hospital, parental knowledge of allergic diseases, and whether the doctor recommended AIT were all statistically different between the groups (p < 0.05). Multifactorial logistic regression analysis showed that the degree of allergic rhinitis (AR), or asthma (AS), parental knowledge of allergic diseases, and doctor's recommendation of AIT were the factors that influenced the willingness of pediatric patients to receive AIT. Conclusions: The severity of AR and AS, parental knowledge of allergic diseases, and doctor's recommendation influenced the willingness of pediatric patients to receive AIT.

Long-term outcomes of vulvar or vaginal cancer patients undergoing laparoendoscopic single-site inguinal lymphadenectomy.

INTRODUCTION: Laparoendoscopic single-site inguinal lymphadenectomy (LESS-IL), a minimally invasive technique, has been reported in patients with vulvar or vaginal cancer regarding its safety and feasibility. However, the long-term outcomes, especially oncologic outcomes, are still lacking. We aimed to evaluate the long-term outcomes of LESS-IL to confirm its safety further. PATIENTS AND METHODS: Data were prospectively collected from patients with vulvar or vaginal cancer who underwent LESS-IL at our institution between July 2018 and June 2021. The patients were followed up for at least 12 months. All procedures were performed according to treatment standards. Short- and long-term complications and oncologic outcomes were analysed. RESULTS: A total of 16 patients undergoing 28 LESS-IL procedures were identified, amongst whom 4 underwent unilateral LESS-IL. The median numbers of excised groin lymph nodes were 9.0 (6.5-11.8) and 10.5 (8.3-12.0) in each left and right groin, respectively. Short-term complications occurred in 4 (25%) patients, including 18.7% lymphocele and 6.3% wound infection. Long-term complications regarding lower-limb lymphoedema appeared in 6 (37.5%) patients. Most short- and long-term complications were Clavien-Dindo 1 or 2, accounting for 90% of all post-operative issues. After a median follow-up of 27 (21.3-35.8) months, only 1 (6.3%) patient had isolated inguinal recurrence at 13 months postoperatively. No local or distant recurrence occurred. CONCLUSION: Our results suggest that LESS-IL is associated with little incidence of complications and promising oncologic outcomes, further demonstrating the safety and feasibility of the LESS-IL technique in patients requiring IL.

Tumor-associated neutrophils upregulate PANoptosis to foster an immunosuppressive microenvironment of non-small cell lung cancer.

Tumor microenvironment (TME) cells orchestrate an immunosuppressive milieu that supports cancer cell proliferation. Tumor-associated neutrophils (TANs) have gained attention as inflammation biomarkers. However, the role of heterogeneous TAN populations in TME immune tolerance and their clinical potential remain unclear. Herein, we used public database to conduct single-cell transcriptomic analysis of 81 patients with non-small cell lung cancer (NSCLC) to elucidate TAN phenotypes linked to unfavorable clinical outcomes. We identified a pro-tumoral TAN cluster characterized by elevated HMGB1 expression, which could potentially engage with the TME through HMGB1-TIM-3 interaction. GATA2 was the transcription factor that drove HMGB1 expression in this pro-tumoral TAN subcluster. Further in vivo experiments confirmed the recruitment of HMGB1-positive TANs to the tumor lesion. Dual-luciferase reporter assays consolidated that the transcription factor GATA2 mediated HMGB1 expression by binding to its promoter region. Moreover, surgical NSCLC specimens verified the putative association between HMGB1-positive TAN and the pathological grades of primary tumors. Overall, this report revealed a pro-tumoral TAN cluster with HMGB1 overexpression that potentially dampen anti-tumoral immunity and contributed to immune evasion via the GATA2/HMGB1/TIM-3 axis. Moreover, this report suggests that this specific phenotype of TAN could serve as an indicator to clinical outcomes and immunotherapy effects for NSCLC.

ST6GALNAC4 promotes hepatocellular carcinogenesis by inducing abnormal glycosylation.

Hepatocellular carcinoma (HCC) is one of the most lethal tumor types worldwide. Glycosylation has shown promise in the study of tumor mechanisms and treatment. The glycosylation status of HCC and the underlying molecular mechanisms are still not fully elucidated. Using bioinformatic analysis we obtained a more comprehensive characterization of glycosylation of HCC. Our analysis presented that high glycosylation levels might correlate with tumor progression and poor prognosis. Subsequent Experiments identified key molecular mechanisms for ST6GALNAC4 promoting malignant progression by inducing abnormal glycosylation. We confirmed the contribution of ST6GALNAC4 to proliferation, migration, and invasion in vitro and in vivo. Mechanistic studies revealed that ST6GALNAC4 may be induced abnormal TGFBR2 glycosylation, resulting in the higher protein levels of TGFBR2 and TGF[Formula: see text] pathway increased activation. Our study also provided a further understand of immunosuppressive function of ST6GALNAC4 through T antigen-galectin3+ TAMs axis. This study has provided one such possibility that galectin3 inhibitors might be an acceptable treatment choice for HCC patients with high T antigen expression.

Engineered exosome-mediated messenger RNA and single-chain variable fragment delivery for human chimeric antigen receptor T-cell engineering.

BACKGROUND AIMS: Most current chimeric antigen receptor (CAR) T cells are generated by viral transduction, which induces persistent expression of CARs and may cause serious undesirable effects. Messenger RNA (mRNA)-based approaches in manufacturing CAR T cells are being developed to overcome these challenges. However, the most common method of delivering mRNA to T cells is electroporation, which can be toxic to cells. METHODS: The authors designed and engineered an exosome delivery platform using the bacteriophage MS2 system in combination with the highly expressed protein lysosome-associated membrane protein 2 isoform B on exosomes. RESULTS: The authors' delivery platform achieved specific loading and delivery of mRNA into target cells and achieved expression of specific proteins, and anti-CD3/CD28 single-chain variable fragments (scFvs) expressed outside the exosomal membrane effectively activated primary T cells in a similar way to commercial magnetic beads. CONCLUSIONS: The delivery of CAR mRNA and anti-CD3/CD28 scFvs via designed exosomes can be used for ex vivo production of CAR T cells with cancer cell killing capacity. The authors' results indicate the potential applications of the engineered exosome delivery platform for direct conversion of primary T cells to CAR T cells while providing a novel strategy for producing CAR T cells in vivo.