The methodological quality of systematic reviews regarding the Core Outcome Set (COS) development.

BACKGROUND: The Core Outcome Measures in Effectiveness Trials (COMET) working group proposed core outcome sets (COS) to address the heterogeneity in outcome measures in clinical studies. According to the recommendations of COMET, performing systematic reviews (SRs) usually was the first step for COS development. However, the SRs that serve as a basis for COS are not specifically appraised by organizations such as COMET regarding their quality. Here, we investigated the status of SRs related to development of COS and evaluated their methodological quality. METHODS: We conducted a search on PubMed to identify SRs related to COS development published from inception to May 2022. We qualitatively summarized the disease included in SR topics, and the studies included in the SRs. We evaluated the methodological quality of the SRs using AMSTAR 2.0 and compared the overall quality of SRs with and without protocols using the Mann-Whitney U test. RESULTS: We included 175 SRs from 23 different countries or regions, and they mainly focused on five diseases: musculoskeletal system or connective tissue disease (n = 19, 10.86%), injury, poisoning, or certain other consequences of external causes (n = 18, 10.29%), digestive system disease (n = 16, 9.14%), nervous system disease (n = 15, 8.57%), and genitourinary system disease (n = 15, 8.57%). Although 88.00% of SRs included randomized controlled trials (RCTs), only a few SRs (23.38%) employed appropriate tools to assess the risk of bias in RCTs. The assessment results on the basis of AMSTAR 2.0 indicated that most SRs (93.71%) were rated as ''critically low'' to ''low'' in terms of overall confidence. The overall confidence of SRs with protocols was significantly higher than that without protocols (P <.001). Compared to the SRs with protocols on Core Outcome Measures in Effectiveness Trials (COMET), SRs with protocols on PROSPERO were of better overall confidence (P = .017). CONCLUSION: The overall quality of published SRs regarding COS development was poor. Our findings emphasize the need for researchers to carefully select the disease topic and strictly adhere to the requirements of optimal methodology when conducting a SR for the establishment of a COS.

Association between Antibiotic Exposure and the Risk of Rash in Children with Infectious Mononucleosis: a Multicenter, Retrospective Cohort Study.

Present evidence suggests that the administration of antibiotics, particularly aminopenicillins, may increase the risk of rash in children with infectious mononucleosis (IM). This retrospective, multicenter cohort study of children with IM was conducted to explore the association between antibiotic exposure in IM children and the risk of rash. A robust error generalized linear regression was performed to address the potential cluster effect, as well as confounding factors such as age and sex. A total of 767 children (aged from 0 to 18 years) with IM from 14 hospitals in Guizhou Province were included in the final analysis. The regression analysis implied that exposure to antibiotics was associated with a significantly increased incidence of overall rash in IM children (adjusted odds ratio [AOR], 1.47; 95% confidence interval [CI], ~1.04 to 2.08; P = 0.029). Of 92 overall rash cases, 43 were probably related to antibiotic exposure: two cases (4.08%) in the amoxicillin-treated group and 41 (8.15%) in the group treated with other antibiotics. Regression analysis indicated that the risk of rash induced by amoxicillin in IM children was similar to that induced by other penicillins (AOR, 1.12; 95% CI, ~0.13 to 9.67), cephalosporins (AOR, 2.45; 95% CI, ~0.43 to 14.02), or macrolides (AOR, 0.91; 95% CI, ~0.15 to 5.43). Antibiotic exposure may be associated with an increased risk of overall rash in IM children, but amoxicillin was not found to be associated with any increased risk of rash during IM compared to other antibiotics. We suggest that clinicians be vigilant against the occurrence of rash in IM children receiving antibiotic therapy, rather than indiscriminately avoiding prescribing amoxicillin.

Fusarium solani G6, a novel vitexin-producing endophytic fungus: characterization, yield improvement and osteoblastic proliferation activity.

The study aimed to characterize a novel vitexin-producing endophytic fungus Fusarium solani G6 from Cajanus cajan, improve its capability for producing vitexin and evaluate its osteoblastic proliferation activity. A total of 153 endophytic fungi, classified into 6 genera, were isolated from C. cajan. Among them, only one strain, endophyte G6 identified as Fusarium solani, was found to produce vitexin. After the optimization of fermentation conditions, the highest vitexin yield (18.72 mg/L) for the strain was observed in PDB liquid medium containing 20.54 g/L of glucose and 8.90 g/L of ammonium sulfate, at an initial medium pH of 5.1 and at 28 °C for 6 days of cultivation. Moreover, the fungal vitexin exhibited notable osteoblastic proliferation stimulating activity. A novel vitexin-producing endophytic fungus F. solani G6 was characterized from C. cajan for the first time. The findings highlighted its potential use for large-scale production of vitexin and might have a promising use as therapeutic agent for osteoporosis.

Off-tumor targets compromise antiangiogenic drug sensitivity by inducing kidney erythropoietin production.

Anti-VEGF drugs are commonly used for treatment of a variety of cancers in human patients, and they often develop resistance. The mechanisms underlying anti-VEGF resistance in human cancer patients are largely unknown. Here, we show that in mouse tumor models and in human cancer patients, the anti-VEGF drug-induced kidney hypoxia augments circulating levels of erythropoietin (EPO). Gain-of-function studies show that EPO protects tumor vessels from anti-VEGF treatment and compromises its antitumor effects. Loss of function by blocking EPO function using a pharmacological approach markedly increases antitumor activity of anti-VEGF drugs through inhibition of tumor angiogenesis. Similarly, genetic loss-of-function data shows that deletion of EpoR in nonerythroid cells significantly increases antiangiogenic and antitumor effects of anti-VEGF therapy. Finally, in a relatively large cohort study, we show that treatment of human colorectal cancer patients with bevacizumab augments circulating EPO levels. These findings uncover a mechanism of desensitizing antiangiogenic and anticancer effects by kidney-produced EPO. Our work presents conceptual advances of our understanding of mechanisms underlying antiangiogenic drug resistance.

Extracellular Albumin Covalently Sequesters Selenocompounds and Determines Cytotoxicity.

Selenocompounds (SeCs) are well-known nutrients and promising candidates for cancer therapy; however, treatment efficacy is very heterogeneous and the mechanism of action is not fully understood. Several SeCs have been reported to have albumin-binding ability, which is an important factor in determining the treatment efficacy of drugs. In the present investigation, we hypothesized that extracellular albumin might orchestrate SeCs efficacy. Four SeCs representing distinct categories were selected to investigate their cytotoxicity, cellular uptake, and species transformation. Concomitant treatment of albumin greatly decreased cytotoxicity and cellular uptake of SeCs. Using both X-ray absorption spectroscopy and hyphenated mass spectrometry, we confirmed the formation of macromolecular conjugates between SeCs and albumin. Although the conjugate was still internalized, possibly via albumin scavenger receptors expressed on the cell surface, the uptake was strongly inhibited by excess albumin. In summary, the present investigation established the importance of extracellular albumin binding in determining SeCs cytotoxicity. Due to the fact that albumin content is higher in humans and animals than in cell cultures, and varies among many patient categories, our results are believed to have high translational impact and clinical implications.

NMR-based serum metabolomics study reveals a innovative diagnostic model for missed abortion.

A missed abortion (MA) is an in-utero death of the embryo or fetus before the 20th week of gestation with retained products of conception. In order to discover novel biomarkers for MA, a 1H NMR spectroscopy-based metabolomics approach was applied to detect human MA serum metabolic profiles. Serum samples were obtained from patients with MA (n = 15) and healthy controls (n = 9) for study. The NOESYPR1D spectrum combined with multi-variate pattern recognition analysis was used to cluster the groups and establish a disease-specific metabolites phenotype. Principal component analysis (PCA) and orthogonal partial least-squares discriminant analysis (OPLS-DA) models were capable of distinguishing MA patients from healthy subjects. The results revealed that 24 metabolites altered in MA patients compared with the control population. Metabolomic pathway analysis demonstrated that alanine, aspartate and glutamate metabolism, citrate cycle (TCA cycle), taurine and hypotaurine metabolism were significantly altered in MA. The results indicated that serum NMR-based metabolomic profiling method is sensitive and specific enough to distinguish MA and from healthy controls, this method could be developed as a clinically useful diagnostic tool for MA. The finding from the MA serum metabolic profiling shed a new light on further understanding of MA disease mechanisms.

Conbercept for patients with age-related macular degeneration: a systematic review.

BACKGROUND: Conbercept is a novel vascular endothelial growth factor (VEGF) inhibitor for the treatment of wet age-related macular degeneration (AMD). This systematic review aims to assess the efficacy and safety of conbercept in the treatment of wet AMD. METHODS: PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure, VIP database, and Wanfang database were searched from their earliest records to June 2017. We included randomized controlled trials (RCTs) evaluating the efficacy and safety of conbercept in wet AMD patients. Outcomes included the mean changes from baseline in best-corrected visual acuity (BCVA) score (primary outcome), central retinal thickness (CRT), plasma level of vascular endothelial growth factor (VEGF) over time, and the incidence of adverse events (AEs). RESULTS: Eighteen RCTs (1285 participants) were included in this systematic review. Conbercept might improve BCVA compared to triamcinolone acetonide [MD = 0.11, 95% CI (0.08, 0.15)], and reduce CRT compared to the other four therapies (conservative treatment, ranibizumab, transpupillary thermotherapy, and triamcinolone acetonide). The incidence of AEs in patients receiving conbercept was significantly lower than those receiving triamcinolone acetonide [RR = 0.25, 95% CI (0.09-0.72)], but was similar to the other therapies. Conbercept seemed to be more effective than ranibizumab in lowering the plasma level of VEGF [MD = - 15.86, 95% CI (- 23.17, - 8.55)]. CONCLUSIONS: Current evidence shows that conbercept is a promising option for the treatment of wet AMD. Nevertheless, further studies are required to compare the efficacy, long-term safety and cost-effectiveness between conbercept and other anti-VEGF agents in different populations.

Rapid and Robust Quantification of p-Xyleneselenocyanate in Plasma via Derivatization.

p-Xyleneselenocyanate (p-XSC) is one of the most investigated selenium compounds in cancer-prevention and -therapy. Despite the potent anticancer property, there is still no proper method to perform the quantitative analysis of p-XSC in plasma. In this investigation, we aimed at developing a method based on liquid chromatography-mass spectrometry (LC-MS) for the measurement of p-XSC in plasma. Direct deproteinization was first used to extract parent p-XSC from plasma, but failed to achieve high recovery rate (<2%) due to formation of selenium-sulfur bond between p-XSC and plasma protein. To overcome this problem, we modified the extraction method to three steps: (1) break the selenium-sulfur bond by tris(2-carboxyethyl)phosphine; (2) stabilize the newly formed intermediate selenol by N-ethylmaleimide; (3) deproteinization. This three-step method efficiently recovered bound p-XSC by more than 75%. In in vivo study, p-XSC was injected intravenously into mice and plasma was collected for LC-MS analysis. Consistently, p-XSC was undetectable in its parent form, whereas the bound form was readily quantified, employing the modified extraction method. In summary, we describe a novel, robust, and sensitive method for quantification of p-XSC in plasma. The present method will enable pharmacokinetic and pharmacodynamic studies of p-XSC in both clinical and preclinical settings.

Astragaloside IV Induced miR-134 Expression Reduces EMT and Increases Chemotherapeutic Sensitivity by Suppressing CREB1 Signaling in Colorectal Cancer Cell Line SW-480.

BACKGROUND: Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths worldwide. Although chemotherapy is the primary means in colorectal cancer treatment, it is burdenerd by adverse drug effects. Drug-resistance is one of the most important challenges for chemotherapy and epithelial-mesenchymal transition (EMT) plays critical role in the development of drug resistance. AIMS: The aim of this study was to investigate the mechanisms underlying the effect of astragaloside IV (AS-IV) on miR-134 expression, EMT and chemotherapeutic sensitivity in CRC. METHODS: Cell proliferation, transfection assay, western blot, real-time PCR, cell migration and invasion assay and luciferase reporter assay were used to detect the effects of AS-IV on CRC. RESULTS: AS-IV significantly inhibited CRC cell migration and invasion by inducing miR-134 expression. Moreover, AS-IV and miR-134 increased the sensitivity of CRC tumors to oxaliplatin (OXA) chemotherapy. cAMP responsive element-binding protein 1 (CREB1), which was required for CRC cells migration, invasion and drug sensitivity, was significantly down-regulated by AS-IV. CONCLUSIONS: Our results indicated that AS-IV inhibited CRC EMT by inducing miR-134 expression which significantly down-regulated the CREB1 signaling pathway, and therefore increased the sensitivity to chemotherapy. Our findings provided new insight into the mechanisms of chemotherapy-resistant CRC, and may open new therapeutic options in the treatment of this devastating disease.

Importance of the surface chemistry of nanoparticles on peroxidase-like activity.

We report the studies on origin of peroxidase-like activity for gold nanoparticles, as well as the impact from morphology and surface charge of nanoparticles. For this purpose, we have synthesized hollow gold nanospheres (HAuNS) and gold nanorods (AuNR) with different morphology and surface chemistry to investigate their influence on the catalytic activity. We found that citrate-capped HAuNS show catalyzing efficiency in oxidation reaction of 3,3',5,5'-tetramethylbenzidine (TMB) by hydrogen peroxide (H2O2) and it is superior to that of cetyltrimethylammonium bromide (CTAB)-capped AuNR. The kinetics of catalytic activities from HAuNS and AuNR were respectively studied under varied temperatures. The results indicated that surface chemistry rather than morphology of nanoparticles plays an important role in the catalytic reaction of substrate. Furthermore, influencing factors such as pH, amount of nanoparticle and H2O2 concentration were also investigated on HAuNS-catalyzed system. The great impact of nanoparticle surface properties on catalytic reactions makes a paradigm in constructing nanozymes as peroxidase mimic for sensing application.

Synthesis and optimization of a bifunctional hyaluronan-based camptothecin prodrug.

Aiming to overcome the low solubility and poor targeting ability of camptothecin (CPT), two hyaluronan (HA)-based polymeric prodrugs with different molecular weights (MW) were synthesized and characterized. The structure of HA-CPT was thoroughly verified by ultraviolet (UV), infrared (IR), (1)H nuclear magnetic resonance ((1)H NMR), differential scanning calorimetry (DSC), and high performance liquid chromatography (HPLC). The conjugation of CPT to HA successfully improved the solubility of CPT from 2.08 to 420-620 µg/mL and enhanced tumor targeting, as shown by the in vitro uptake and cytotoxicity results. Moreover, it was found that the high MW conjugate exhibited higher drug loading, higher stability but lower solubility compared with the low MW conjugate. Both HA-CPT conjugates exhibited similar uptake efficiency and antitumor activity. The results demonstrated that HA could act as an effective solubilization carrier and targeting molecule in a HA-based CPT prodrug.

Ultrasound-triggered functional hydrogel promotes multistage bone regeneration.

The dysfunction of bone mesenchymal stem cells (BMSCs), caused by the physical and chemical properties of the inflammatory and repair phases of bone regeneration, contributes to the failure of bone regeneration. To meet the spatiotemporal needs of BMSCs in different phases, designing biocompatible materials that respond to external stimuli, improve migration in the inflammatory phase, reduce apoptosis in the proliferative phase, and clear the hurdle in the differentiation phase of BMSCs is an effective strategy for multistage repair of bone defects. In this study, we designed a cascade-response functional composite hydrogel (Gel@Eb/HA) to regulate BMSCs dysfunction in vitro and in vivo. Gel@Eb/HA improved the migration of BMSCs by upregulating the expression of chemokine (C-C motif) ligand 5 (CCL5) during the inflammatory phase. Ultrasound (US) triggered the rapid release of Ebselen (Eb), eliminating the accumulation of reactive oxygen species (ROS) in BMSCs, and reversing apoptosis under oxidative stress. Continued US treatment accelerated the degradation of the materials, thereby providing Ca2+ for the osteogenic differentiation of BMSCs. Altogether, our study highlights the prospects of US-controlled intelligent system, that provides a novel strategy for addressing the complexities of multistage bone repair.

An umbrella review of the diagnostic value of next-generation sequencing in infectious diseases.

BACKGROUND: An increasing number of systematic reviews (SRs) have evaluated the diagnostic values of next-generation sequencing (NGS) in infectious diseases (IDs). AIM: This umbrella analysis aimed to assess the potential risk of bias in existing SRs and to summarize the published diagnostic values of NGS in different IDs. METHOD: We searched PubMed, Embase, and the Cochrane Library until September 2023 for SRs assessing the diagnostic validity of NGS for IDs. Two investigators independently determined review eligibility, extracted data, and evaluated reporting quality, risk of bias, methodological quality, and evidence certainty in the included SRs. RESULTS: Eleven SRs were analyzed. Most SRs exhibited a moderate level of reporting quality, while a serious risk of bias was observed in all SRs. The diagnostic performance of NGS in detecting pneumocystis pneumonia and periprosthetic/prosthetic joint infection was notably robust, showing excellent sensitivity (pneumocystis pneumonia: 0.96, 95% CI 0.90-0.99, very low certainty; periprosthetic/prosthetic joint infection: 0.93, 95% CI 0.83-0.97, very low certainty) and specificity (pneumocystis pneumonia: 0.96, 95% CI 0.92-0.98, very low certainty; periprosthetic/prosthetic joint infection: 0.95, 95% CI 0.92-0.97, very low certainty). NGS exhibited high specificity for central nervous system infection, bacterial meningoencephalitis, and tuberculous meningitis. The sensitivity to these infectious diseases was moderate. NGS demonstrated moderate sensitivity and specificity for multiple infections and pulmonary infections. CONCLUSION: This umbrella analysis indicates that NGS is a promising technique for diagnosing pneumocystis pneumonia and periprosthetic/prosthetic joint infection with excellent sensitivity and specificity. More high-quality original research and SRs are needed to verify the current findings.

Antibody-displaying extracellular vesicles for targeted cancer therapy.

Extracellular vesicles (EVs) function as natural delivery vectors and mediators of biological signals across tissues. Here, by leveraging these functionalities, we show that EVs decorated with an antibody-binding moiety specific for the fragment crystallizable (Fc) domain can be used as a modular delivery system for targeted cancer therapy. The Fc-EVs can be decorated with different types of immunoglobulin G antibody and thus be targeted to virtually any tissue of interest. Following optimization of the engineered EVs by screening Fc-binding and EV-sorting moieties, we show the targeting of EVs to cancer cells displaying the human epidermal receptor 2 or the programmed-death ligand 1, as well as lower tumour burden and extended survival of mice with subcutaneous melanoma tumours when systemically injected with EVs displaying an antibody for the programmed-death ligand 1 and loaded with the chemotherapeutic doxorubicin. EVs with Fc-binding domains may be adapted to display other Fc-fused proteins, bispecific antibodies and antibody-drug conjugates.

EV-mediated promotion of myogenic differentiation is dependent on dose, collection medium, and isolation method.

Extracellular vesicles (EVs) have been implicated in the regulation of myogenic differentiation. C2C12 murine myoblast differentiation was reduced following treatment with GW4869 or heparin (to inhibit exosome biogenesis and EV uptake, respectively). Conversely, treatment with C2C12 myotube-conditioned medium enhanced myogenic differentiation. Ultrafiltration-size exclusion liquid chromatography (UF-SEC) was used to isolate EVs and non-EV extracellular protein in parallel from C2C12 myoblast- and myotube-conditioned medium. UF-SEC-purified EVs promoted myogenic differentiation at low doses (≤2 × 108 particles/mL) and were inhibitory at the highest dose tested (2 × 1011 particles/mL). Conversely, extracellular protein fractions had no effect on myogenic differentiation. While the transfer of muscle-enriched miRNAs (myomiRs) has been proposed to mediate the pro-myogenic effects of EVs, we observed that they are scarce in EVs (e.g., 1 copy of miR-133a-3p per 195 EVs). Furthermore, we observed pro-myogenic effects with undifferentiated myoblast-derived EVs, in which myomiR concentrations are even lower, suggestive of a myomiR-independent mechanism underlying the observed pro-myogenic effects. During these investigations we identified technical factors with profound confounding effects on myogenic differentiation. Specifically, co-purification of insulin (a component of Opti-MEM) in non-EV LC fractions and polymer precipitated EV preparations. These findings provide further evidence that polymer-based precipitation techniques should be avoided in EV research.

Identification of scaffold proteins for improved endogenous engineering of extracellular vesicles.

Extracellular vesicles (EVs) are gaining ground as next-generation drug delivery modalities. Genetic fusion of the protein of interest to a scaffold protein with high EV-sorting ability represents a robust cargo loading strategy. To address the paucity of such scaffold proteins, we leverage a simple and reliable assay that can distinguish intravesicular cargo proteins from surface- as well as non-vesicular proteins and compare the EV-sorting potential of 244 candidate proteins. We identify 24 proteins with conserved EV-sorting abilities across five types of producer cells. TSPAN2 and TSPAN3 emerge as lead candidates and outperform the well-studied CD63 scaffold. Importantly, these engineered EVs show promise as delivery vehicles in cell cultures and mice as demonstrated by efficient transfer of luminal cargo proteins as well as surface display of different functional entities. The discovery of these scaffolds provides a platform for EV-based engineering.

Cutaneous squamous cell carcinoma-derived extracellular vesicles exert an oncogenic role by activating cancer-associated fibroblasts.

Cutaneous squamous cell carcinoma (cSCC) is a fast-increasing cancer with metastatic potential. Extracellular vesicles (EVs) are small membrane-bound vesicles that play important roles in intercellular communication, particularly in the tumor microenvironment (TME). Here we report that cSCC cells secrete an increased number of EVs relative to normal human epidermal keratinocytes (NHEKs) and that interfering with the capacity of cSCC to secrete EVs inhibits tumor growth in vivo in a xenograft model of human cSCC. Transcriptome analysis of tumor xenografts by RNA-sequencing enabling the simultaneous quantification of both the human and the mouse transcripts revealed that impaired EV-production of cSCC cells prominently altered the phenotype of stromal cells, in particular genes related to extracellular matrix (ECM)-formation and epithelial-mesenchymal transition (EMT). In line with these results, co-culturing of human dermal fibroblasts (HDFs) with cSCC cells, but not with normal keratinocytes in vitro resulted in acquisition of cancer-associated fibroblast (CAF) phenotype. Interestingly, EVs derived from metastatic cSCC cells, but not primary cSCCs or NHEKs, were efficient in converting HDFs to CAFs. Multiplex bead-based flow cytometry assay and mass-spectrometry (MS)-based proteomic analyses revealed the heterogenous cargo of cSCC-derived EVs and that especially EVs derived from metastatic cSCCs carry proteins associated with EV-biogenesis, EMT, and cell migration. Mechanistically, EVs from metastatic cSCC cells result in the activation of TGFß signaling in HDFs. Altogether, our study suggests that cSCC-derived EVs mediate cancer-stroma communication, in particular the conversion of fibroblasts to CAFs, which eventually contribute to cSCC progression.

Surface display of functional moieties on extracellular vesicles using lipid anchors.

Extracellular vesicles (EVs) are efficient natural vehicles for intercellular communication and are under extensive investigation for the delivery of diverse therapeutics including small molecule drugs, nucleic acids, and proteins. To understand the mechanisms behind the biological activities of EVs and develop EV therapeutics, it's fundamental to track EVs and engineer EVs in a customized manner. In this study, we identified, using single-vesicle flow cytometry and microscopy, the lipid DOPE (dioleoyl phosphatidyl ethanolamine) as an efficient anchor for isolated EVs. Notably, DOPE associated with EVs quickly, and the products remained stable under several challenging conditions. Moreover, conjugating fluorophores, receptor-targeting peptides or albumin-binding molecules with DOPE enabled tracking the cellular uptake, enhanceing the cellular uptake or extending the circulation time in mice of engineered EVs , respectively. Taken together, this study reports an efficient lipid anchor for exogenous engineering of EVs and further showcases its versatility for the functionalization of EVs.

Cell-specific targeting of extracellular vesicles through engineering the glycocalyx.

Extracellular vesicles (EVs) are promising carriers for the delivery of a variety of chemical and biological drugs. However, their efficacy is limited by the lack of cellular specificity. Available methods to improve the tissue specificity of EVs predominantly rely on surface display of proteins and peptides, largely overlooking the dense glycocalyx that constitutes the outermost layer of EVs. In the present study, we report a reconfigurable glycoengineering strategy that can endogenously display glycans of interest on EV surface. Briefly, EV producer cells are genetically engineered to co-express a glycosylation domain (GD) inserted into the large extracellular loop of CD63 (a well-studied EV scaffold protein) and fucosyltransferase VII (FUT7) or IX (FUT9), so that the engineered EVs display the glycan of interest. Through this strategy, we showcase surface display of two types of glycan ligands, sialyl Lewis X (sLeX) and Lewis X, on EVs and achieve high specificity towards activated endothelial cells and dendritic cells, respectively. Moreover, the endothelial cell-targeting properties of sLeX-EVs were combined with the intrinsic therapeutic effects of mesenchymal stem cells (MSCs), leading to enhanced attenuation of endothelial damage. In summary, this study presents a reconfigurable glycoengineering strategy to produce EVs with strong cellular specificity and highlights the glycocalyx as an exploitable trait for engineering EVs.

Growth Media Conditions Influence the Secretion Route and Release Levels of Engineered Extracellular Vesicles.

Extracellular vesicles (EVs) are nanosized cell-derived vesicles produced by all cells, which provide a route of intercellular communication by transmitting biological cargo. While EVs offer promise as therapeutic agents, the molecular mechanisms of EV biogenesis are not yet fully elucidated, in part due to the concurrence of numerous interwoven pathways which give rise to heterogenous EV populations in vitro. The equilibrium between the EV-producing pathways is heavily influenced by factors in the extracellular environment, in such a way that can be taken advantage of to boost production of engineered EVs. In this study, a quantifiable EV-engineering approach is used to investigate how different cell media conditions alter EV production. The presence of serum, exogenous EVs, and other signaling factors in cell media alters EV production at the physical, molecular, and transcriptional levels. Further, it is demonstrated that the ceramide-dependent EV biogenesis route is the major pathway to production of engineered EVs during optimized EV-production. These findings suggest a novel understanding to the mechanisms underlying EV production in cell culture which can be applied to develop advanced EV production methods.