Endocytosis blocks the vesicular secretion of exosome marker proteins.

Exosomes are secreted vesicles of ~30 to 150 nm diameter that play important roles in human health and disease. To better understand how cells release these vesicles, we examined the biogenesis of the most highly enriched human exosome marker proteins, the exosomal tetraspanins CD81, CD9, and CD63. We show here that endocytosis inhibits their vesicular secretion and, in the case of CD9 and CD81, triggers their destruction. Furthermore, we show that syntenin, a previously described exosome biogenesis factor, drives the vesicular secretion of CD63 by blocking CD63 endocytosis and that other endocytosis inhibitors also induce the plasma membrane accumulation and vesicular secretion of CD63. Finally, we show that CD63 is an expression-dependent inhibitor of endocytosis that triggers the vesicular secretion of lysosomal proteins and the clathrin adaptor AP-2 mu2. These results suggest that the vesicular secretion of exosome marker proteins in exosome-sized vesicles occurs primarily by an endocytosis-independent pathway.

Exploring the regulatory role of FBXL19-AS1 in triple-negative breast cancer through the miR-378a-3p/OTUB2 axis.

The regulatory potential of long noncoding RNA (lncRNA) FBXL19-AS1 has been highlighted in various cancers, but its effect on triple-negative breast cancer (TNBC) remains unclear. Here, we aimed to elucidate the role of FBXL19-AS1 in TNBC and its underlying mechanism. RT-qPCR was employed to detect the expressions of FBXL19-AS1 and miR-378a-3p in tissues and cells. Immunohistochemical staining and western blot were utilized to detect the expression levels of proteins. Cell activities were detected using flow cytometry, CCK-8, and transwell assay. Dual-luciferase reporter and RNA immunoprecipitation (RIP) assays were deployed to investigate interactions of different molecules. Protein-protein interaction (PPI) network, gene ontology (GO), and Kyoto encyclopedia of genes and genomes (KEGG) pathways were used to analyze the downstream pathway. In vivo xenograft model was conducted to detect the effect of FBXL19-AS1 on tumor growth. FBXL19-AS1 was overexpressed in TNBC tissues and cell lines compared with counterparts. FBXL19-AS1 knockdown suppressed TNBC cell activities, whereas its overexpression exhibited the opposite effect. Mechanistically, FBXL19-AS1 was found to interact with miR-378a-3p. Further analysis revealed that miR-378a-3p exerted tumor-suppressive effects in TNBC cells. Additionally, miR-378a-3p targeted and downregulated the expression of ubiquitin aldehyde binding 2 (OTUB2), a deubiquitinase associated with TNBC progression. In vivo experiments substantiated the inhibitory effects of FBXL19-AS1 knockdown on TNBC tumorigenesis, and a miR-378a-3p inhibitor partially rescued these effects. The downstream pathway of the miR-378a-3p/OTUB2 axis was explored, revealing connections with proteins involved in modifying other proteins, removing ubiquitin molecules, and influencing signaling pathways, including the Hippo signaling pathway. Western blot analysis confirmed changes in YAP and TAZ expression levels, indicating a potential regulatory network. In summary, FBXL19-AS1 promotes exacerbation in TNBC by suppressing miR-378a-3p, leading to increased OTUB2 expression. The downstream mechanism may be related to the Hippo signaling pathway. These findings propose potential therapeutic targets for TNBC treatment.

Three-dimensional surgical margin positioning technique versus palpation-guided method for breast-conserving surgery: Feasibility, advantages, and quality of life.

BACKGROUND: The accurate evaluation of surgical margins holds crucial importance in determining the success of breast-conserving surgery (BCS). The aim of this study was to introduce a novel technique for the positioning of surgical margins in BCS while highlighting its advantages. METHODS: This study included a cohort of breast cancer patients who underwent BCS. The patients were categorized into two groups: one group underwent BCS with the traditional palpation-guided method, and the other with the 3D-MPT technique. The study assessed and compared the feasibility, advantages, and outcomes in terms of quality of life between the two groups. RESULTS: A total of 80 patients were successfully enrolled in the study. No significant differences in clinicopathological features were observed between the two groups. The 3D-MPT technique was found to be feasible and offered several advantages over the palpation-guided method. The utilization of guide wires by experienced radiologists to position the margins before surgery enabled precise and swift specimen removal, resulting in the conservation of valuable time and a reduction in the need for re-excision. Furthermore, the 3D-MPT technique exhibited the potential to enhance cosmetic outcomes and elevate patient satisfaction, particularly in cases with uncertain tumor boundaries detectable by palpation. CONCLUSION: The 3D-MPT technique proves to be an effective and safe approach for reducing tumor positivity rates in initial surgical margins, thereby improving the quality of life for patients undergoing breast-conserving surgery in comparison to the conventional method.

Antigen-display exosomes provide adjuvant-free protection against SARS-CoV-2 disease at nanogram levels of spike protein.

As the only bionormal nanovesicle, exosomes have high potential as a nanovesicle for delivering vaccines and therapeutics. We show here that the loading of type-1 membrane proteins into the exosome membrane is induced by exosome membrane anchor domains, EMADs, that maximize protein delivery to the plasma membrane, minimize protein sorting to other compartments, and direct proteins into exosome membranes. Using SARS-CoV-2 spike as an example and EMAD13 as our most effective exosome membrane anchor, we show that cells expressing a spike-EMAD13 fusion protein produced exosomes that carry dense arrays of spike trimers on 50% of all exosomes. Moreover, we find that immunization with spike-EMAD13 exosomes induced strong neutralizing antibody responses and protected hamsters against SARS-CoV-2 disease at doses of just 0.5-5 ng of spike protein, without adjuvant, demonstrating that antigen-display exosomes are particularly immunogenic, with important implications for both structural and expression-dependent vaccines.

Interleukin-17D produced by alveolar epithelial type II cells alleviates LPS-induced acute lung injury via the Nrf2 pathway.

BACKGROUND: Sepsis engenders an imbalance in the body's inflammatory response, with cytokines assuming a pivotal role in its progression. A relatively recent addition to the interleukin-17 family, denominated interleukin-17D (IL-17D), is notably abundant within pulmonary confines. Nevertheless, its implication in sepsis remains somewhat enigmatic. The present study endeavors to scrutinize the participation of IL-17D in sepsis-induced acute lung injury (ALI). METHODS: The levels of IL-17D in the serum and bronchoalveolar lavage fluid (BALF) of both healthy cohorts and septic patients were ascertained through an ELISA protocol. For the creation of a sepsis-induced ALI model, intraperitoneal lipopolysaccharide (LPS) injections were administered to male C57/BL6 mice. Subsequently, we examined the fluctuations and repercussions associated with IL-17D in sepsis-induced ALI, probing its interrelation with nuclear factor erythroid 2-related factor 2 (Nrf2), alveolar epithelial permeability, and heme oxygenase-1. RESULTS: IL-17D levels exhibited significant reduction both in the serum and BALF of septic patients (P<0.001). Similar observations manifested in mice subjected to LPS-induced acute lung injury (ALI) (P=0.002). Intraperitoneal administration of recombinant interleukin 17D protein (rIL-17D) prompted increased expression of claudin 18 and concomitant enhancement of alveolar epithelial permeability, thus, culminating in improved lung injury (P<0.001). Alveolar epithelial type II (ATII) cells were identified as the source of IL-17D, regulated by Nrf2. Furthermore, a deficiency in HO-1 yielded elevated IL-17D levels (P=0.004), albeit administration of rIL-17D ameliorated the exacerbated pulmonary damage resulting from HO-1 deficiency. CONCLUSION: Nrf2 fosters IL-17D production within AT II cells, thereby conferring a protective role in sepsis-induced ALI.

Recent advances and pathological mechanisms in photodynamic and sonodynamic therapy in the treatment of bone tumors (Review).

Given the recent advances that have been made with photodynamic therapy (PDT) combined with sonodynamic therapy (SDT) (PDT/SDT; also known as SPDT), the application of this combination therapy in the clinic has provided another major breakthrough in the medical field, especially with regard to the treatment of deep tumors. Concerning its application in the treatment of bone tumors, numerous pathological mechanisms have been taken advantage of to overcome the barrier of tissue hypoxia, and SPDT is expected to achieve radical effects, with high penetration depth and low aggressiveness. In the present review, it is comprehensively shown how, according to the histoanatomy of bone tumors, PDT and SDT target cells in a coordinated manner, affecting such processes as necrotizing apoptosis, pyroptosis, autophagy and ferroptosis on the macroscopic level, and crucially, thrombosis at the vascular level, which leads to the triggering of immunogenic cell death in local and distant locations. Additionally, PDT and SDT have been shown to have roles in: i) degrading the extracellular matrix; ii) influencing the receptor activator of nuclear factor­κB (RANK)/RANK ligand signaling pathway; iii) disrupting the equilibrium between glutathione peroxidase 4 and reactive oxygen species (ROS); and iv) destroying the microscopic structure of the bone tumor. Upon PDT/SDT stimulation, several mechanisms act in concert to ensure that the targeted bone tumor is eliminated. Furthermore, widely distributed ROS have been revealed to promote osteoclast formation and osteogenic mineralization through the regulation of macrophages, processes that greatly improve the effects of postoperative repair. Finally, the developmental prospects of bone tumor engineering in the future are discussed in the present review.

Syntenin and CD63 Promote Exosome Biogenesis from the Plasma Membrane by Blocking Cargo Endocytosis.

Exosomes are small extracellular vesicles important in health and disease. Syntenin is thought to drive the biogenesis of CD63 exosomes by recruiting Alix and the ESCRT machinery to endosomes, initiating an endosome-mediated pathway of exosome biogenesis. Contrary to this model, we show here that syntenin drives the biogenesis of CD63 exosomes by blocking CD63 endocytosis, thereby allowing CD63 to accumulate at the plasma membrane, the primary site of exosome biogenesis. Consistent with these results, we find that inhibitors of endocytosis induce the exosomal secretion of CD63, that endocytosis inhibits the vesicular secretion of exosome cargo proteins, and that high-level expression of CD63 itself also inhibits endocytosis. These and other results indicate that exosomes bud primarily from the plasma membrane, that endocytosis inhibits their loading into exosomes, that syntenin and CD63 are expression-dependent regulators of exosome biogenesis, and that syntenin drives the biogenesis of CD63 exosomes even in Alix knockout cells.

Solasodine suppresses the metastasis of gastric cancer through claudin-2 via the AMPK/STAT3/NF-κB pathway.

Gastric cancer (GC) is one of the most common malignancies, and it has become the third most common malignant tumour in the world. Targeting metastasis has also become a key and difficult point in the treatment of GC. Solasodine is an active ingredient isolated from Solanum nigrum L. for the treatment of various cancers, such as breast cancer, pancreatic cancer and lung cancer. In the present study, we investigated the role and mechanism of solasodine in inhibiting GC. In vitro, we found that solasodine not only promoted cell death but also inhibited the migration and invasion of HGC27 and AGS cells. Solasodine regulated epithelial-mesenchymal transition (EMT) and reduced the expression of claudin-2 (CLDN2). Moreover, overexpression of CLDN2 inhibited the prometastatic phenotype and EMT of GC, and solasodine recovered this phenotype. Furthermore, the knockdown of CLDN2 had the opposite effect. We also found that the AMPK activators metformin and AICAR activated phosphorylation of AMPK and downregulated the expression of RhoA and CLDN2, indicating that AMPK was the upstream regulator of CLDN2. Solasodine could also activate AMP-activated protein kinase (AMPK) and inhibit the phosphorylation of STAT3 and the nuclear translocation of NF-κB. Therefore, solasodine may have prevented EMT by modulating the AMPK/STAT3/NF-κB/CLDN2 signalling pathway. In vivo, we established a xenograft model to investigate the phosphorylation of AMPK and the expression of CLDN2 from tumour tissues, and we found that solasodine inhibited tumour growth through AMPK-CLDN2 pathway. To sum up, solasodine prevented EMT by modulating the AMPK/STAT3/NF-κB/CLDN2 signalling pathway, becoming a new solution for inhibiting GC metastasis.

Protective Effect of Electroacupuncture on the Barrier Function of Intestinal Injury in Endotoxemia through HO-1/PINK1 Pathway-Mediated Mitochondrial Dynamics Regulation.

Background and Aims: Endotoxemia (ET) is a common critical illness in patients receiving intensive care and is associated with high mortality and prolonged hospital stay. The intestinal epithelial cell dysfunction is regarded as the "engine" of deteriorated ET. Although electroacupuncture (EA) can mitigate endotoxin-induced intestinal epithelial cell dysfunction in ET, the mechanism through which EA improves endotoxin-induced intestinal injury for preventing ET deterioration needs further investigation. Methods: An in vivo ET model was developed by injecting lipopolysaccharide (LPS) in wild-type and PINK1-knockout mice. An in vitro model was also established by incubating epithelial cells in the serum samples obtained from both groups of mice. Hemin and zinc protoporphyrin IX (ZnPP) were applied to activate or inhibit heme oxygenase 1 (HO-1) production. EA treatment was performed for 30 min consecutively for 5 days before LPS injection, and on the day of the experiment, EA was performed throughout the process. Samples were harvested at 6 h after LPS induction for analyzing tissue injury, oxidative stress, ATP production, activity of diamine oxidase (DAO), and changes in the levels of HO-1, PTEN-induced putative kinase 1 (PINK1), mitochondrial fusion and fission marker gene, caspase-1, and interleukin 1 beta (IL-1ß). Results: In the wild-type models (both in vivo and vitro), EA alleviated LPS-induced intestinal injury and mitochondrial dysfunction, as indicated by decreased reactive oxygen species (ROS) production and oxygen consumption rate (OCR) and reduced levels of mitochondrial fission proteins. EA treatment also boosted histopathological morphology, ATP levels, DAO activity, and levels of mitochondrial fusion proteins in vivo and vitro. The effect of EA was enhanced by hemin but suppressed by Znpp. However, EA + AP, Znpp, or hemin had no effects on the LPS-induced, PINK1-knocked out mouse models. Conclusion: EA may improve the HO-1/PINK1 pathway-mediated mitochondrial dynamic balance to protect the intestinal barrier in patients with ET.

The D614G mutation redirects SARS-CoV-2 spike to lysosomes and suppresses deleterious traits of the furin cleavage site insertion mutation.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) egress occurs by lysosomal exocytosis. We show that the Spike D614G mutation enhances Spike trafficking to lysosomes, drives Spike-mediated reprogramming of lysosomes, and reduces cell surface Spike expression by ~3-fold. D614G is not a human-specific adaptation. Rather, it is an adaptation to the earlier furin cleavage site insertion (FCSI) mutation that occurred at the genesis of SARS-CoV-2. While advantageous to the virus, furin cleavage of spike has deleterious effects on spike structure and function, inhibiting its trafficking to lysosomes and impairing its infectivity by the transmembrane serine protease 2(TMPRSS2)-independent, endolysosomal pathway. D614G restores spike trafficking to lysosomes and enhances the earliest events in SARS-CoV-2 infectivity, while spike mutations that restore SARS-CoV-2's TMPRSS2-independent infectivity restore spike's trafficking to lysosomes. Together, these and other results show that D614G is an intragenic suppressor of deleterious traits linked to the FCSI and lend additional support to the endolysosomal model of SARS-CoV-2 egress and entry.

An effective method to reduce lymphatic drainage post-lateral cervical lymph node dissection of differentiated thyroid cancer: a retrospective analysis.

BACKGROUND: Lymph or chyle leak (LL/CL) is severe complications after lateral cervical lymph node dissection (LLND), mainly due to iatrogenic injury of the lymphatic duct. Efficient and well-operated methods to reduce postoperative drainage are still lacking. This was a feasibility study to evaluate a new method of preventing LL/CL compared to conventional treatment. METHOD: We retrospectively analyzed 20 consecutive patients who used the "pedicled omohyoid flap covering (POFC)" method during LLND from January 2019 to December 2021 in our center as an observation group. Another 20 consecutive patients used the conventional method during LLND in this period as a control group. The clinical and pathological features of the two groups were compared, and the related factors that affected postoperative lymphatic drainage were analyzed with Cox proportional hazards models. RESULTS: The drainage volume per 24 h and the incidence of LL/CL in the control group were both higher than that in the observation group (all P < 0.05), and the number of lymph nodes dissected in the IV region > 10 and the use of the POFC method were the independent risk factors that significantly affected the incidence of LL/CL post LLND (all P < 0.05). CONCLUSIONS: POFC is a safe and useful method for reducing drainage and preventing LL/CL post-LLND, especially for patients with heavy metastasis of the lymph nodes in the IV region.

A shared, stochastic pathway mediates exosome protein budding along plasma and endosome membranes.

Exosomes are small extracellular vesicles of ∼30 to 150 nm that are secreted by all cells, abundant in all biofluids, and play important roles in health and disease. However, details about the mechanism of exosome biogenesis are unclear. Here, we carried out a cargo-based analysis of exosome cargo protein biogenesis in which we identified the most highly enriched exosomal cargo proteins and then followed their biogenesis, trafficking, and exosomal secretion to test different hypotheses for how cells make exosomes. We show that exosome cargo proteins bud from cells (i) in exosome-sized vesicles regardless of whether they are localized to plasma or endosome membranes, (ii) ∼5-fold more efficiently when localized to the plasma membrane, (iii) ∼5-fold less efficiently when targeted to the endosome membrane, (iv) by a stochastic process that leads to ∼100-fold differences in their abundance from one exosome to another, and (v) independently of small GTPase Rab27a, the ESCRT complex-associated protein Alix, or the cargo protein CD63. Taken together, our results demonstrate that cells use a shared, stochastic mechanism to bud exosome cargoes along the spectrum of plasma and endosome membranes and far more efficiently from the plasma membrane than the endosome. Our observations also indicate that the pronounced variation in content between different exosome-sized vesicles is an inevitable consequence of a stochastic mechanism of small vesicle biogenesis, that the origin membrane of exosome-sized extracellular vesicles simply cannot be determined, and that most of what we currently know about exosomes has likely come from studies of plasma membrane-derived vesicles.

Oncogenic Long Noncoding RNA Linc01287 Promotes IGF1R Expression by Sponging miR-98 in Breast Cancer.

Long noncoding RNA (LncRNA) dysregulation has been shown to exhibit a regulatory effect in various cancers. However, the effect of LINC01287 on breast cancer (BC) has not been illustrated. The aim of this research was to explore the expression and function of LncRNA LINC01287 in BC. LINC01287 expression in clinical tissues and BC cell lines was detected. The luciferase reporter assay was performed to verify the correlation between LINC01287, microRNA 98 (miR-98), and the insulin-like growth factor 1 receptor (IGF1R). The CCK-8 assay was performed to examine cell viability. Cell invasion and migration capacity was determined by transwell and wound healing assays. The protein level of IGF1R, phosphorylated mitogen-activated protein kinase 1 and 2 (p-MEK1/2), and phosphorylated extracellular signal-regulated kinase 1 and 2 (p-ERK1/2) was analyzed by western blotting. LINC01287 expression markedly increased in BC cell lines. Subsequent studies identified LINC01287 as a downstream target of miR-98. In addition, LINC01287 knockdown and miR-98 overexpression significantly stagnated progression of BC cells. LINC01287 knockdown also downregulated IGF1R levels. Moreover, LINC01287 knockdown notably downregulated the phosphorylation of MEK1/2 and ERK1/2. The in vivo assay verified that LINC01287 can regulate tumorigenesis of BC. Our findings showed that LINC01287 was overexpressed in BC cells and tissues. LINC01287 promoted the malignant characteristics of BC cells and acted as an oncogene. Its regulatory effect may be associated with the miR-98/IGF1R/MEK/ERK signaling pathway. Therefore, LINC01287 has potential for use as a biomarker or therapeutic target for the treatment of BC.

Relationship Between CNVs and Immune Cells Infiltration in Gastric Tumor Microenvironment.

Gastric cancer (GC) is a highly fatal and common malignancy of the digestive system. Recent therapeutic advancements have significantly improved the clinical outcomes in GC, but due to the unavailability of suitable molecular targets, a large number of patients do not respond to the immune checkpoint inhibitors (ICI) therapy. To identify and validate potential therapeutic and prognostic targets of gastric cancer, we used the "inferCNV" R package for analyzing single-cell sequencing data (GSE112302) of GC and normal epithelial cells. First, by using LASSO, we screened genes that were highly correlated with copy number variations (CNVs). Therefrom, five gene signature (CPVL, DDC, GRTP1, ONECUT2, and PRSS21) was selected by cross-validating the prognosis and risk management with the GC RNA-seq data obtained from GEO and TCGA. Moreover, the correlation analyses between CNVs of these genes and immune cell infiltration in gastric cancer identified CPVL as a potential prognostic marker. Finally, CPVL showed high expression in gastric cancer samples and cell lines, then siRNA-mediated silencing of CPVL expression in gastric cancer cells showed significant proliferation arrest in MGC803 cells. Here, we conclude that CNVs are key regulators of the immune cells infiltration in gastric TME as well as cancer development, and CPVL could potentially be used as a prognostic and therapeutic marker in gastric cancer.

Comprehensive Analysis of Colorectal Cancer Immunity and Identification of Immune-Related Prognostic Targets.

Colorectal cancer (COAD) is ranked as the third most common cancer and second in terms of cancer-related deaths worldwide. Due to its poor overall survival and prognosis, the incidents of COAD are significantly increasing. Although treatment methods have greatly been improved in the last decade, it is still not good enough to have satisfactory treatment outcomes. In recent years, immunotherapy has been successful to some extent in the treatment of many cancers but still, many patients do not respond to immunotherapy. Therefore, it is essential to have a deeper understanding of the immune characteristics of the tumor microenvironment and identify meaningful immune targets. In terms of immune targets, COAD has been poorly explored; thus, in the current study, based on the immune cell infiltration score and differentially expressed genes, COAD tumors were classified into hot and cold tumors. The Least Absolute Shrinkage and Selection Operator (LASSO) regression analysis was used to identify hub genes, construct a prognostic model, and screen potential immune targets. In total, 12 genes (CLK3, CYSLTR2, GJA10, CYP4Z1, FAM185A, LINC00324, EEF1A1P34, EEF1B2P8, PTCSC3, MIR6780A, LINC01666, and RNU6.661P) differentially expressed between hot and cold tumors were screened out. Among them, CYSLTR2 was considered as a potential candidate gene, because it showed a significant positive correlation with immune cell infiltration and immune checkpoints (PDCD1, CD274, and CTLA4). Finally, we constructed and validated a new prognostic model for COAD showing 0.854 AUC for the ROC curve, and these results provide sufficient potential to choose CYSLTR2 as an important immune target for the prognosis of COAD.

Degron tagging of BleoR and other antibiotic-resistance genes selects for higher expression of linked transgenes and improved exosome engineering.

Five antibiotic resistance (AR) genes have been used to select for transgenic eukaryotic cell lines, with the BleoR, PuroR, HygR, NeoR, and BsdR cassettes conferring resistance to zeocin, puromycin, hygromycin, geneticin/G418, and blasticidin, respectively. We recently demonstrated that each AR gene establishes a distinct threshold of transgene expression below which no cell can survive, with BleoR selecting for the highest level of transgene expression, nearly ∼10-fold higher than in cells selected using the NeoR or BsdR markers. Here, we tested the hypothesis that there may be an inverse proportionality between AR protein function and the expression of linked, transgene-encoded, recombinant proteins. Specifically, we fused each AR protein to proteasome-targeting degron tags, used these to select for antibiotic-resistant cell lines, and then measured the expression of the linked, recombinant protein, mCherry, as a proxy marker of transgene expression. In each case, degron-tagged AR proteins selected for higher mCherry expression than their cognate WT AR proteins. ER50BleoR selected for the highest level of mCherry expression, greater than twofold higher than BleoR or any other AR gene. Interestingly, use of ER50BleoR as the selectable marker translated to an even higher, 3.5-fold increase in the exosomal loading of the exosomal cargo protein, CD63/Y235A. Although a putative CD63-binding peptide, CP05, has been used to decorate exosome membranes in a technology known as "exosome painting," we show here that CP05 binds equally well to CD63-/- cells, WT 293F cells, and CD63-overexpressing cells, indicating that CP05 may bind membranes nonspecifically. These results are of high significance for cell engineering and especially for exosome engineering.

Continued Virus-Specific Antibody-Secreting Cell Production, Avidity Maturation and B Cell Evolution in Patients Hospitalized with COVID-19.

Understanding the development and sustainability of the virus-specific protective immune response to infection with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) remains incomplete with respect to the appearance and disappearance of virus-specific antibody-secreting cells (ASCs) in circulation. Therefore, we performed cross-sectional and longitudinal analyses of peripheral blood mononuclear cells and plasma collected from 55 hospitalized patients up to 4 months after onset of COVID-19 symptoms. Spike (S)- and nucleocapsid (N)-specific IgM and IgG ASCs appeared within 2 weeks accompanied by flow cytometry increases in double negative plasmablasts consistent with a rapid extrafollicular B cell response. Total and virus-specific IgM and IgG ASCs peaked at 3-4 weeks and were still being produced at 3-4 months accompanied by increasing antibody avidity consistent with a slower germinal center B cell response. N-specific ASCs were produced for longer than S-specific ASCs and avidity maturation was greater for antibody to N than S. Patients with more severe disease produced more S-specific IgM and IgG ASCs than those with mild disease and had higher levels of N- and S-specific antibody. Women had more B cells in circulation than men and produced more S-specific IgA and IgG and N-specific IgG ASCs. Flow cytometry analysis of B cell phenotypes showed an increase in circulating B cells at 4-6 weeks with decreased percentages of switched and unswitched memory B cells. These data indicate ongoing antigen-specific stimulation, maturation, and production of ASCs for several months after onset of symptoms in patients hospitalized with COVID-19.

Gambogenic Acid Induces Endoplasmic Reticulum Stress in Colorectal Cancer via the Aurora A Pathway.

Colorectal cancer (CRC) is one of the most common malignancies in the world and has a poor prognosis. In the present research, gambogenic acid (GNA), isolated from the traditional Chinese medicine gamboge, markedly induced apoptosis and inhibited the proliferation of CRC in vitro and in vivo. Furthermore, GNA triggered endoplasmic reticulum (ER) stress, which subsequently activated inositol-requiring enzyme (IRE) 1α and the eukaryotic translation initiation factor (eIF) 2α pathway. Pretreatment with salubrinal (an eIF2α inhibitor) rescued GNA-induced cell death. Furthermore, GNA downregulated the expression of Aurora A. The Aurora A inhibitor alisertib decreased ER stress. In human colorectal adenocarcinoma tissue, Aurora A was upregulated compared to normal colorectal epithelial nuclei. Furthermore, GNA ameliorated mouse colitis-associated cancer models. Our findings demonstrated that GNA significantly inhibited the proliferation of CRC through activation of ER stress by regulating Aurora A, which indicates the potential of GNA for preventing the progression of CRC.

Exosome-mediated mRNA delivery in vivo is safe and can be used to induce SARS-CoV-2 immunity.

Functional delivery of mRNA has high clinical potential. Previous studies established that mRNAs can be delivered to cells in vitro and in vivo via RNA-loaded lipid nanoparticles (LNPs). Here we describe an alternative approach using exosomes, the only biologically normal nanovesicle. In contrast to LNPs, which elicited pronounced cellular toxicity, exosomes had no adverse effects in vitro or in vivo at any dose tested. Moreover, mRNA-loaded exosomes were characterized by efficient mRNA encapsulation (∼90%), high mRNA content, consistent size, and a polydispersity index under 0.2. Using an mRNA encoding the red light-emitting luciferase Antares2, we observed that mRNA-loaded exosomes were superior to mRNA-loaded LNPs at delivering functional mRNA into human cells in vitro. Injection of Antares2 mRNA-loaded exosomes also led to strong light emission following injection into the vitreous fluid of the eye or into the tissue of skeletal muscle in mice. Furthermore, we show that repeated injection of Antares2 mRNA-loaded exosomes drove sustained luciferase expression across six injections spanning at least 10 weeks, without evidence of signal attenuation or adverse injection site responses. Consistent with these findings, we observed that exosomes loaded with mRNAs encoding immunogenic forms of the SARS-CoV-2 Spike and Nucleocapsid proteins induced long-lasting cellular and humoral responses to both. Taken together, these results demonstrate that exosomes can be used to deliver functional mRNA to and into cells in vivo.

Ultrafast vibrational dynamics of the tyrosine ring mode and its application to enkephalin insertion into phospholipid membranes as probed by two-dimensional infrared spectroscopy.

Enkephalins are small opioid peptides whose binding conformations are catalyzed by phospholipid membranes. Binding to opioid receptors is determined by the orientation of tyrosine and phenylalanine side chains. In this work, we investigate the effects of different charged phospholipid headgroups on the insertion of the tyrosine side chain into a lipid bilayer using a combination of 2D IR spectroscopy, anharmonic DFT calculations, and third order response function modeling. The insertion is probed by using the ∼1515 cm-1 tyrosine ring breathing mode, which we found exhibits rich vibrational dynamics on the picosecond timescale. These dynamics include rapid intramolecular vibrational energy redistribution (IVR), where some of the energy ends up in a dark state that shows up as an anharmonically shifted combination band. The waiting-time dependent 2D IR spectra also show an unusual line shape distortion that affects the extraction of the frequency-frequency correlation function (FFCF), which is the dynamic observable of interest that reflects the tyrosine side chain's insertion into the lipid bilayer. We proposed three models to account for this distortion: a hot-state exchange model, a local environment dependent IVR model, and a coherence transfer model. A qualitative analysis of these models suggests that the local environment dependent IVR rate best explains the line shape distortion, while the coherence transfer model best reproduced the effects on the FFCF. Even with these complex dynamics, we found that the tyrosine ring mode's FFCF is qualitatively correlated with the degree of insertion expected from the different phospholipid headgroups.