Exosome-based delivery of super-repressor IκBα ameliorates kidney ischemia-reperfusion injury

Ischemia-reperfusion injury is a major cause of acute kidney injury. Recent studies on the pathophysiology of ischemia-reperfusion-induced acute kidney injury showed that immunologic responses significantly affect kidney ischemia-reperfusion injury and repair. Nuclear factor (NF)-ĸB signaling, which controls cytokine production and cell survival, is significantly involved in ischemia-reperfusion-induced acute kidney injury, and its inhibition can ameliorate ischemic acute kidney injury. Using EXPLOR, a novel, optogenetically engineered exosome technology, we successfully delivered the exosomal super-repressor inhibitor of NF-ĸB (Exo-srIĸB) into B6 wild type mice before/after kidney ischemia-reperfusion surgery, and compared outcomes with those of a control exosome (Exo-Naïve)-injected group. Exo-srIĸB treatment resulted in lower levels of serum blood urea nitrogen, creatinine, and neutrophil gelatinase-associated lipocalin in post-ischemic mice than in the Exo-Naïve treatment group. Systemic delivery of Exo-srIĸB decreased NF-ĸB activity in post-ischemic kidneys and reduced apoptosis. Post-ischemic kidneys showed decreased gene expression of pro-inflammatory cytokines and adhesion molecules with Exo-srIĸB treatment as compared with the control. Intravital imaging confirmed the uptake of exosomes in neutrophils and macrophages. Exo-srIĸB treatment also significantly affected post-ischemic kidney immune cell populations, lowering neutrophil, monocyte/macrophage, and T cell frequencies than those in the control. Thus, modulation of NF-ĸB signaling through exosomal delivery can be used as a novel therapeutic method for ischemia-reperfusion-induced acute kidney injury.

Extracellular vesicles in kidneys and their clinical potential in renal diseases

Extracellular vesicles (EVs), such as exosomes and microvesicles, are cell-derived lipid bilayer membrane particles, which deliver information from host cells to recipient cells. EVs are involved in various biological processes including the modulation of the immune response, cell-to-cell communications, thrombosis, and tissue regeneration. Different types of kidney cells are known to release EVs under physiologic as well as pathologic conditions, and recent studies have found that EVs have a pathophysiologic role in different renal diseases. Given the recent advancement in EV isolation and analysis techniques, many studies have shown the diagnostic and therapeutic potential of EVs in various renal diseases, such as acute kidney injury, polycystic kidney disease, chronic kidney disease, kidney transplantation, and renal cell carcinoma. This review updates recent clinical and experimental findings on the role of EVs in renal diseases and highlights the potential clinical applicability of EVs as novel diagnostics and therapeutics.

Biodistribution and Pharmacokinectics of Liposomes and Exosomes in a Mouse Model of Sepsis

Exosomes have attracted considerable attention as drug delivery vehicles because their biological properties can be utilized for selective delivery of therapeutic cargoes to disease sites. In this context, analysis of the in vivo behaviors of exosomes in a diseased state is required to maximize their therapeutic potential as drug delivery vehicles. In this study, we investigated biodistribution and pharmacokinetics of HEK293T cell-derived exosomes and PEGylated liposomes, their synthetic counterparts, into healthy and sepsis mice. We found that biodistribution and pharmacokinetics of exosomes were significantly affected by pathophysiological conditions of sepsis compared to those of liposomes. In the sepsis mice, a substantial number of exosomes were found in the lung after intravenous injection, and their prolonged blood residence was observed due to the liver dysfunction. However, liposomes did not show such sepsis-specific effects significantly. These results demonstrate that exosome-based therapeutics can be developed to manage sepsis and septic shock by virtue of their sepsis-specific in vivo behaviors.

Exosomal delivery of NF-κB inhibitor delays LPS-induced preterm birth and modulates fetal immune cell profile in mouse models

Accumulation of immune cells and activation of the pro-inflammatory transcription factor NF-κB in feto-maternal uterine tissues is a key feature of preterm birth (PTB) pathophysiology. Reduction of the fetal inflammatory response and NF-κB activation are key strategies to minimize infection-associated PTB. Therefore, we engineered extracellular vesicles (exosomes) to contain an NF-κB inhibitor, termed super-repressor (SR) IκBα. Treatment with SR exosomes (1 × 1010 per intraperitoneal injection) after lipopolysaccharide (LPS) challenge on gestation day 15 (E15) prolonged gestation by over 24 hours (PTB ≤ E18.5) and reduced maternal inflammation (n ≥ 4). Furthermore, using a transgenic model in which fetal tissues express the red fluorescent protein tdTomato while maternal tissues do not, we report that LPS-induced PTB in mice is associated with influx of fetal innate immune cells, not maternal, into feto-maternal uterine tissues. SR packaged in exosomes provides a stable and specific intervention for reducing the inflammatory response associated with PTB.

Extra-domain B of fibronectin as an alternative target for drug delivery and a cancer diagnostic and prognostic biomarker for malignant glioma

Extra-domain B of fibronectin (EDB-FN) is an alternatively spliced form of fibronectin with high expression in the extracellular matrix of neovascularized tissues and malignant cancer cells. In this study, we evaluated the practicality of using EDB-FN as a biomarker and therapeutic target for malignant gliomas (MGs), representative intractable diseases involving brain tumors.

Methods: The microarray- and sequence-based patient transcriptomic database 'Oncopression' and tissue microarray of MG patient tissue samples were analyzed. EDB-FN data were extracted and evaluated from 23,344 patient samples of 17 types of cancer to assess its effectiveness and selectivity as a molecular target. To strengthen the results of the patient data analysis, the utility of EDB-FN as a molecular marker and target for MG was verified using active EDB-FN-targeting ultrasmall lipidic micellar nanoparticles (~12 nm), which had a high drug-loading capacity and were efficiently internalized by MG cells in vitro and in vivo.

Results: Brain tumors had a 1.42-fold cancer-to-normal ratio (p < 0.0001), the second highest among 17 cancers after head and neck cancer. Patient tissue microarray analysis showed that the EDB-FN high-expression group had a 5.5-fold higher risk of progression than the EDB-FN low-expression group (p < 0.03). By labeling docetaxel-containing ultrasmall micelles with a bipodal aptide targeting EDB-FN (termed APT_EDB-DSPE-DTX), we generated micelles that could specifically bind to MG cells, leading to superior antitumor efficacy of EDB-FN-targeting nanoparticles compared to nontargeting controls.

Conclusions: Taken together, these results show that EDB-FN can be an effective drug delivery target and biomarker for MG.

The emerging role of exosomes as novel therapeutics: Biology, technologies, clinical applications, and the next

The extracellular vesicles (EVs) research area has grown rapidly because of their pivotal roles in intercellular communications and maintaining homeostasis of individual organism. As a subtype of EVs, exosomes are made via unique biogenesis pathway and exhibit disparate functional and phenotypic characteristics. Functionally, exosomes transfer biological messages from donor cell to recipient cell, which makes exosomes as a novel therapeutic platform delivering therapeutic materials to the target tissue/cell. Currently, both academia and industry try to develop exosome platform‐based therapeutics for disease management, some of which are already in clinical trials. In this review, we will discuss focusing on therapeutic values of exosomes, recent advances in therapeutic exosome platform development, and late development of exosome therapeutics in diverse therapeutic areas.

Bibliometric analysis of manuscript characteristics that influence citations: A comparison of ten major dermatology journals

BACKGROUND

The number of citations an article receives is a reassuring marker for its influence in the academic world.

OBJECTIVE

We aimed to discover characteristics of dermatology articles that may impact their citation.

METHODS

This cross-sectional study collected and analyzed articles published between January and June 2013 from ten highest impact dermatology journals. The study included manuscript characteristics i.e. the length of an article, the presence of visual aids, accessibility, originality, and clarity. Citation analysis statistics required multiple tools such as linear regression, point-biserial correlation, Spearman's rank-order correlation, and Kruskal-Wallis to determine the association between these study variables and the number of citations of articles.

RESULTS

Of 748 articles included in our study, the number of citations ranged from 0 to 814 (median: 18), with weak positive correlations to the length of manuscript (word count: r_s 0.3, p<0.001; pages: r_s 0.3, p<0.001). Having a structured abstract (r_pb -0.15, p<0.001) and increasing number of references (r_s -0.26, p<0.001) showed a negative correlation. Studies originating in North America were associated with higher citations, followed by Europe and Asia (p<0.001). Review articles had a higher number of citations (p<0.001).

CONCLUSIONS

We found that the number of words and the number of pages within a dermatology manuscript had the strongest positive correlation for a higher citation count. The results of this study can benefit authors who may improve the citation of their articles by utilizing this bibliometric study when assembling their manuscript.

Exosome-based delivery of super-repressor IκBα relieves sepsis-associated organ damage and mortality

As extracellular vesicles that play an active role in intercellular communication by transferring cellular materials to recipient cells, exosomes offer great potential as a natural therapeutic drug delivery vehicle. The inflammatory responses in various disease models can be attenuated through introduction of super-repressor IκB (srIκB), which is the dominant active form of IκBα and can inhibit translocation of nuclear factor κB into the nucleus. An optogenetically engineered exosome system (EXPLOR) that we previously developed was implemented for loading a large amount of srIκB into exosomes. We showed that intraperitoneal injection of purified srIκB-loaded exosomes (Exo-srIκBs) attenuates mortality and systemic inflammation in septic mouse models. In a biodistribution study, Exo-srIκBs were observed mainly in the neutrophils, and in monocytes to a lesser extent, in the spleens and livers of mice. Moreover, we found that Exo-srIκB alleviates inflammatory responses in monocytic THP-1 cells and human umbilical vein endothelial cells.

Cyclic-recombinase-reporter mouse model to determine exosome communication and function during pregnancy

BACKGROUND

During pregnancy, feto-maternal communication can be mediated through extracellular vesicles, specifically exosomes, 30- to 150-nm particles released from each cell. Exosomes carry cellular signals, and traffic between fetal and maternal tissues to produce functional changes in recipient cells. Exosomes may function as a biomarker indicative of the physiologic status of their tissue of origin. These properties of exosomes during pregnancy are not well studied.

OBJECTIVE

To test exosome trafficking and function, we used a transgenic mouse model containing membrane-targeted, red fluorescent protein tdTomato and enhanced green fluorescent protein cyclic recombinase-reporter construct expressed only in fetal tissues. This model allows fetal tissues and their exosomes to express tdTomato under normal conditions or green fluorescent protein if fetal tissues are exposed to cyclic recombinase that will excise tdTomato. As maternal tissue remains negative for this construct, tdTomato/green fluorescent protein expression and their switching can be used to determine fetal-specific cell and exosome trafficking.

MATERIALS AND METHODS

tdTomato/green fluorescent protein-homozygous male mice were mated with wild-type females to have all fetal tissues express the tdTomato/green fluorescent protein allele. Red fluorescence due to tdTomato expression of the tdTomato/green fluorescent protein allele in fetal tissues (placenta, fetal membranes) was confirmed by confocal microscopy on embryonic day 16. Localization of fetal exosomes in maternal uterine tissues were performed by immunostaining for exosome marker CD81 and tdTomato expression followed by confocal microscopy. Fetal exosomes (tdTomato-positive) in maternal plasma were immunoprecipitated using anti-red fluorescent protein tdTomato, followed by confirmation with flow cytometry. To further illustrate the fidelity of fetal exosomes in maternal samples, exosomes bioengineered to contain cyclic recombinase (1.0 × 1010 exosomes) were injected intraperitoneally on embryonic day 13. On embryonic day 16, fetal (placenta and fetal membranes) tissues were imaged to show tdTomato-to-green fluorescent protein transition. The green fluorescent protein-expressing exomes were localized in maternal tissues (confocal microscopy) and plasma (flow cytometry).

RESULTS

Mating between a male with the tdTomato/green fluorescent protein construct and a null female resulted in fetal tissues and their exosomes expressing tdTomato positivity. Total fetal exosomes in maternal plasma was about 35%. tdTomato-positive exosomes were isolated from maternal plasma and immunostaining localized tdTomato-positive exosomes in maternal uterine tissues. Maternal intraperitoneal injection of cyclic recombinase-enriched exosomes crossed placenta, excised tdTomato from the tdTomato/green fluorescent protein construct in the fetal tissues, and caused green fluorescent protein expression in fetal cells. Furthermore, green fluorescent protein-positive exosomes released from fetal cells were isolated from maternal blood.

CONCLUSION

In this pilot study, we report feto-maternal and maternal-fetal trafficking of exosomes indicative of paracrine signaling during pregnancy. Exosomes from the maternal side can produce functional changes in fetal tissues. Trafficking of exosomes suggests their potential role in pregnancy as biomarkers of fetal functions and usefulness as a carrier of drugs and other cargo to the fetal side during pregnancy. Isolation and characterization of fetal exosomes can advance fetal research without performing invasive procedures.

Mesenchymal Stem Cell-Derived Extracellular Vesicles as Therapeutics and as a Drug Delivery Platform

Mesenchymal stem cells (MSCs) are one of the most easily accessible stem cells that can be obtained from various human tissues. They have raised considerable interests for their potential applications in tissue repair, anti‐cancer therapy, and inflammation suppression. Stem cell‐based therapy was first used to treat muscular dystrophies and has been studied intensively for its efficacy in various disease models, including myocardial infarction, kidney injuries, liver injuries, and cancers. In this review, we summarized the potential mechanisms underlying MSC‐derived EVs therapy as a drug delivery platform. Additionally, based on currently published data, we predicted a potential therapeutic role of cargo proteins shuttled by EVs from MSCs. These data may support the therapeutic strategy of using the MSC‐derived EVs to accelerate this strategy from bench to bedside. stem cells translational medicine2019;8:880&886

Detection of viable but nonculturable Vibrio parahaemolyticus induced by prolonged cold-starvation using propidium monoazide real-time polymerase chain reaction

Viable but nonculturable (VBNC) Vibrio parahaemolyticus cannot be detected by the standard cultivation-based methods. In this study, commonly used viability assessment methods were evaluated for the detection of V. parahaemolyticus in a VBNC state. Vibrio parahaemolyticus cells exposed to nutrient deficiency at cold temperature were used for epifluorescence microscopy with SYTO₉ and propidium iodide (PI) staining and real-time polymerase chain reaction (qPCR) with propidium monoazide (PMA), and its resuscitative ability was determined by a temperature upshift in freshly prepared artificial sea water (ASW; pH 7) fluids. Viable cells with intact membranes always exceeded 5·0 log CFU per ml in ASW microcosms at 4°C. After 80 days, cycle thresholds for V. parahaemolyticus ATCC 27969 were 16·15-16·69. During cold-starvation, PMA qPCR selectively excluded DNAs from heat-killed cells. However, there may be some penetration of PMA into undamaged cells that persisted in ASW for 150 days, as evidenced by their ability to resuscitate from a VBNC state after a temperature upshift (25°C); V. parahaemolyticus ATCC 33844 and V. parahaemolyticus ATCC 27969 were successfully reactivated from a VBNC state in ASW microcosms containing <5% NaCl, following enrichment in ASW medium (pH 7). SIGNIFICANCE AND IMPACT OF THE STUDY: Few studies have evaluated the characteristics of and detection methods for viable but nonculturable (VBNC) Vibrio parahaemolyticus induced by cold-starvation. Currently, VBNC cells are routinely detected by SYTO₉ and propidium iodide double staining. However, viable cell counts might be overestimated by this approach, suggesting that the fluorescence dyes may be ineffective for accurately determining the viability of bacterial cells. We demonstrated that quantitative real-time polymerase chain reaction with propidium monoazide, which selectively permeates damaged cell membranes, can be used to obtain viable cell counts of V. parahaemolyticus after its evolution to a VBNC state under cold-starvation conditions.