Bioactive Cargo Research Articles

Artificial Cell-Penetrating Peptide Containing Periodic α-Aminoisobutyric Acid with Long-Term Internalization Efficiency in Human and Plant Cells.

Cell-penetrating peptides (CPPs) have been widely utilized as efficient molecular tools for the delivery of bioactive cargoes such as peptides, proteins, and genetic material. However, to improve their versatility as tools in biological environments, the resistance of CPPs to enzymatic degradation and their structural stability must be improved to achieve long-term efficacy. Here we designed and synthesized novel artificial CPPs, poly(LysAibXaa), containing periodic α-aminoisobutyric acid (Aib) and l-lysine by chemoenzymatic polymerization. Poly(LysAibAla) tended to form 310- and α-helical structures under the amphiphilic cell-membrane-mimicking environment. Poly(LysAibXaa) exhibited long-term internalization and thus high accumulation in live cells, which is attributed to the improvement in the resistance to proteolytic digestion as a result of the incorporation of Aib residues into the peptide backbone. We presented a simple molecular design and synthesis of efficient CPPs applicable to both human and plant cells with long-term stability and negligible cytotoxicity.

Inflammation‐induced Extracellular Vesicles Cause Endothelial Barrier Injury

Extracellular vesicles (EVs) are a heterogenous population of sub‐micron sized vesicles released by cells during physiological or pathological stimulation. Circulating vesicles not only serve as important diagnostic/prognostic biomarkers, but also interact with blood or vascular cells and regulate multiple cellular processes by transferring bioactive cargo. In this study, we characterized EV production and cargo signature in the blood of healthy human subjects and burn patients, as well as in cultured human endothelial cells (ECs) after inflammatory stimulation. We also examined the effects of EVs on endothelial barrier structure and function. The results showed that the plasma level of EVs was increased during sterile inflammation in burn patients, with a significant portion of them derived from leukocytes and the endothelium. Interestingly, the EVs from burn patients expressed higher levels of c‐Src, protein kinase C and focal adhesion kinase, compared to EVs from healthy blood donors. In cultured ECs treated with tumor necrosis factor alpha, there was an increased production of EVs into the culture media. Furthermore, treating endothelial cells with EVs induced myosin light chain and VE‐cadherin phosphorylation and actin stress fiber formation in concomitance with adherens junction discontinuity. Functionally, EV treatment caused an increase in albumin flux across endothelial monolayers in a concentration‐dependent manner. EVs derived from c‐Src knockdown parent ECs displayed an attenuated effect on barrier protein phosphorylation and permeability. Likewise, pharmacological inhibition of Src activity reduced EV‐induced protein phosphorylation and barrier dysfunction in endothelial cells. Together, the data suggest that EVs produced during inflammation carry protein kinases capable of damaging the endothelial barrier.Support or Funding InformationNIH grants HL126646, HL070752 (to SYY), and GM097270. The human blood study was approved by the University of South Florida IRB and supported by the institutional research funds.

Biomaterials functionalized with MSC secreted extracellular vesicles and soluble factors for tissue regeneration.

The therapeutic benefits of mesenchymal stromal cell (MSC) transplantation have been attributed to their secreted factors, including extracellular vesicles (EVs) and soluble factors. The potential of employing the MSC secretome as an alternative acellular approach to cell therapy is being investigated in various tissue injury indications, but EVs administered via bolus injections are rapidly sequestered and cleared. However, biomaterials offer delivery platforms to enhance EV retention rates and healing efficacy. In this review, we highlight the mechanisms underpinning the therapeutic effects of MSC-EVs and soluble factors as effectors of immunomodulation and tissue regeneration, conferred primarily via their nucleic acid and protein contents. We discuss how manipulating the cell culture microenvironment or genetic modification of MSCs can further augment the potency of their secretions. The most recent advances in the development of EV-functionalized biomaterials that mediate enhanced angiogenesis and cell survival, while attenuating inflammation and fibrosis, are presented. Finally, some technical challenges to be considered for the clinical translation of biomaterials carrying MSC-secreted bioactive cargo are discussed.

Membrane-bound exosomal HSP70 as a biomarker for detection and monitoring of malignant solid tumours: a pilot study

BackgroundCancer is the second leading cause of death globally. Early detection and disease management lead to a better survival rate. Consequently, discovery of novel methods in cancer early diagnosis is a field of active research. Minimally invasive liquid biopsies are generating growing interest. Circulating tumour cells (CTCs) have been identified in patients’ blood; nevertheless, these cells are rare and heterogeneous. Exosomes are extracellular nanovesicles released into the extracellular environment via the endosomal vesicle pathway and found in different body fluids. Exosomes deliver bioactive cargo such as proteins, mRNA and miRNA to recipient cells in the tumour environment. We have recently shown that heat shock protein 70 (HSP70) is detected in the membrane of tumour-derived exosomes, in contrast to normal cells. One single cancer cell can release thousands of HSP70-exosomes, facilitating detection. The aim of the pilot study ExoDiag is to determine whether it is possible to detect and quantify HSP70-exosomes in blood in patients with solid cancers.MethodsBicentric pilot study that will include 60 adult patients with metastatic and non-metastatic solid tumours and 20 healthy volunteers. Exosomes will be isolated from blood and urine samples, and HSP70 concentration will be determined. Patients will be followed for 1 year. The study is sponsored by Georges-François Leclerc Centre and is currently ongoing.DiscussionWe expect to demonstrate that HSP70-exosomes could be a powerful tool to diagnose cancer and to guide clinicians in therapeutic decision-making, improving patient’s care.Trial RegistrationClinicalTrials.gov identifier NCT02662621. Registered 20 January 2016, https://clinicaltrials.gov/ct2/show/study/NCT02662621?term=NCT02662621&rank=1

Extracellular Vesicles as Mediators of Cellular Crosstalk Between Immune System and Kidney Graft

Extracellular vesicles (EVs) are known immune-modulators exerting a critical role in kidney transplantation (KT). EV bioactive cargo includes graft antigens, costimulatory/inhibitory molecules, cytokines, growth factors, and functional microRNAs (miRNAs) that may modulate expression of recipient cell genes. As paracrine factors, neutrophil- and macrophage-derived EVs exert immunosuppressive and immune-stimulating effects on dendritic cells, respectively. Dendritic cell-derived EVs mediate alloantigen spreading and modulate antigen presentation to T lymphocytes. At systemic level, EVs exert pleiotropic effects on complement and coagulation. Depending on their biogenesis, they can amplify complement activation or shed complement inhibitors and prevent cell lysis. Likewise, endothelial- and platelet-derived EVs can exert procoagulant/prothrombotic effects and also promote endothelial survival and angiogenesis after ischemic injury. Kidney endothelial- and tubular-derived EVs play a key role in ischemia–reperfusion injury (IRI) and during the healing process; additionally, they can trigger rejection by inducing both alloimmune and autoimmune responses. Endothelial EVs have procoagulant/pro-inflammatory effects and can release sequestered self-antigens, generating a tissue-specific autoimmunity. Renal tubule-derived EVs shuttle pro-fibrotic mediators (TGF-β and miR-21) to interstitial fibroblasts and modulate neutrophil and T-lymphocyte influx. These processes can lead to peritubular capillary rarefaction and interstitial fibrosis–tubular atrophy. Different EVs, including those from mesenchymal stromal cells (MSCs), have been employed as a therapeutic tool in experimental models of rejection and IRI. These particles protect tubular and endothelial cells (by inhibition of apoptosis and inflammation–fibrogenesis or by inducing autophagy) and stimulate tissue regeneration (by triggering angiogenesis, cell proliferation, and migration). Finally, urinary and serum EVs represent potential biomarkers for delayed graft function (DGF) and acute rejection. In conclusion, EVs sustain an intricate crosstalk between graft tissue and innate/adaptive immune systems. EVs play a major role in allorecognition, IRI, autoimmunity, and alloimmunity and are promising as biomarkers and therapeutic tools in KT.

A novel approach to a controlled opening of liposomes

A novel strategy is described for preparing pH-sensitive liposomes which releases the encapsulated drug in response to the change in pH of surrounding solution. The liposomes, composed of conventional zwitter-ionic egg yolk lecithin (EL), additionally contains a pH-sensitive “activator” (AMS), a derivative of lithocholic acid with anionic and cationic groups attached to the opposite ends of the steroid core. AMS changes its orientation in the liposomal membrane thus adapting to acidity/basicity of the outer solution. The rotation of AMS induces disordering of the membrane and a fast release of the bioactive cargo. In particular, 50–60 % of the encapsulated antitumor drug, doxorubicin and cisplatin, leaks from the liposomes within the first minute after acidification of the surrounding solution. Low-toxic EL-AMS liposomes, loaded with doxorubicin, show themselves active towards multidrug resistant cells. Fast-acting and low-toxic EL-AMS liposomes can be used in the design of smart liposomal containers in the drug delivery field.

Whey protein aggregates formed by non-toxic chemical cross-linking as novel carriers for curcumin delivery: Fabrication and characterization

Whey protein isolate (WPI) was first treated with citric acid as a cross-linker to yield whey protein aggregates (WPA). Formation of aggregates through the covalent cross-linking was confirmed by SDS-PAGE. After that, with curcumin as a bioactive cargo, the potential application of WPA as carriers was investigated. WPA showed a remarkable higher loading capacity and efficiency for curcumin than non-treated WPI. The fluorescence spectroscopy revealed that curcumin could combine to WPA by hydrophobic interactions and quench the intrinsic fluorescence of WPA. The size, polydispersity index, viscosity, and consistency coefficient of WPA were significantly enhanced by adding of curcumin. The secondary structures of WPA were influenced by loading of curcumin as revealed by circular dichroism spectroscopy. X-ray diffraction and differential scanning calorimetry analysis revealed that the crystallinity of curcumin was decreased by loading into the WPA. In addition, the curcumin-loaded WPA had stronger antioxidant activity as measured by reducing power test than the free curcumin suggesting the additive effect between WPA and curcumin. The release studies showed that the release of curcumin from WPA in the gastric condition was relatively low, but increased in the simulated intestinal phase. Generally, the obtained whey protein aggregates are potential to become new curcumin delivery systems.

Value of detection of extracellular vesicles in the diagnosis of nonalcoholic fatty liver disease

Extracellular vesicles (EVs) are small bilayer lipid membrane vesicles that can be released by most cell types and detected in most body fluids. EVs exert key functions for intercellular communication via transferring their bioactive cargos to recipient cells or activating signaling pathways in target cells, and hence participate in the variety of diseases including the occurrence and development of liver diseases. In recent years, the prevalence of nonalcoholic fatty liver disease (NAFLD) has increased. Currently there is no reliable method except invasive liver biopsy for the diagnosis of liver inflammation or fibrosis staging. Therefore, the search for the corresponding markers of noninvasive circulation continues to be active, and extracellular vesicles are one of the most concerned. To this end, we reviewed current knowledge about the physical characteristics, biological components, and isolation methods of extracellular vesicles, and introduced the concept of using circulating cell-derived vesicles as a new diagnostic marker for nonalcoholic fatty liver disease.

Extracellular vesicles and their roles in stem cell biology.

Stem cells use a variety of mechanisms to help maintain their pluripotency and promote self-renewal, as well as, at the appropriate time, to differentiate into specialized cells. One such mechanism that is attracting significant attention from the stem cell, development, and regenerative medicine research communities involves a form of intercellular communication, specifically, the ability of cells to form and release nontraditional membrane-enclosed structures, referred to as extracellular vesicles (EVs). There are two major classes of EVs, microvesicles (MVs), which are generated through the outward budding and fission of the plasma membrane, and exosomes, which are formed as multivesicular bodies (MVBs) in the endo-lysosomal pathway that fuse with the cell surface to release their contents. Although they differ in how they are formed, both MVs and exosomes have been shown to contain a diverse array of bioactive cargo, such as proteins, RNA transcripts, microRNAs, and even DNA, which can be transferred to other cells and promote phenotypic changes. Here, we will describe what is currently known regarding EVs and the roles they play in stem cell biology and different aspects of early development. We will also highlight how the EVs produced by stem cells are being aggressively pursued for clinical applications, including their potential use as therapeutic delivery systems and for their regenerative capabilities.

Exosomes from mmu_circ_0001359-Modified ADSCs Attenuate Airway Remodeling by Enhancing FoxO1 Signaling-Mediated M2-like Macrophage Activation

Asthma is the most common chronic disease and is characterized by airway remodeling and chronic inflammation. Increasingly, studies have found that the activation and M1 phenotypic transformation of macrophages play important roles in asthma progress, including airway remodeling. However, the reversal of M1 macrophages to the M2 phenotype has been shown to attenuate airway remodeling. Exosomes are nano-sized extracellular vesicles derived from endosomes; they play direct roles in governing physiological and pathological conditions by the intracellular transfer of bioactive cargo, such as proteins, enzymes, nucleic acids (microRNA [miRNA], mRNA, DNA), and metabolites. However, transfer mechanisms are unclear. To uncover potential therapeutic mechanisms, we constructed an ovalbumin-induced asthma mouse model and lipopolysaccharide-induced RAW264.7 macrophages cells. High-throughput sequencing showed that mmu_circ_0001359 was downregulated in asthmatic mice when compared with normal mice. Adipose-derived stem cell (ADSC)-exosome treatment suppressed inflammatory cytokine expression by the conversion of M1 macrophages to the M2 phenotype, under lipopolysaccharide-induced conditions. Exosomes from mmu_circ_0001359 overexpression in ADSCs increased therapeutic effects, in terms of cytokine expression, when compared with wild-type exosomes. Luciferase reporter assays confirmed that exosomes from mmu_circ_0001359-modified ADSCs attenuated airway remodeling by enhancing FoxO1 signaling-mediated M2-like macrophage activation, via sponging miR-183-5p. In conclusion, mmu_circ_0001359-enriched exosomes attenuated airway remodeling by promoting M2-like macrophages.

Extracellular vesicles in Inflammatory Skin Disorders: from Pathophysiology to Treatment.

Extracellular vesicles (EVs), naturally secreted by almost all known cell types into extracellular space, can transfer their bioactive cargos of nucleic acids and proteins to recipient cells, mediating cell-cell communication. Thus, they participate in many pathogenic processes including immune regulation, cell proliferation and differentiation, cell death, angiogenesis, among others. Cumulative evidence has shown the important regulatory effects of EVs on the initiation and progression of inflammation, autoimmunity, and cancer. In dermatology, recent studies indicate that EVs play key immunomodulatory roles in inflammatory skin disorders, including psoriasis, atopic dermatitis, lichen planus, bullous pemphigoid, systemic lupus erythematosus, and wound healing. Importantly, EVs can be used as biomarkers of pathophysiological states and/or therapeutic agents, both as carriers of drugs or even as a drug by themselves. In this review, we will summarize current research advances of EVs from different cells and their implications in inflammatory skin disorders, and further discuss their future applications, updated techniques, and challenges in clinical translational medicine.

Hydrocarbon staple constructing highly efficient α-helix cell-penetrating peptides for intracellular cargo delivery.

The effects of all-hydrocarbon cross-linking on the cell-penetrating properties of Tat were systematically investigated. These stapled cell-penetrating peptides were designed to exhibit a cationic secondary amphipathic profile. We found that the hydrophobicity and helical conformation of these hydrocarbon staple peptides correlate well with their cellular uptake efficiency. Our results also revealed that higher affinity to heparan sulfate of the rigid stapled Tat peptides correlated well with the higher cellular uptake compared with non-stapled Tat peptides with flexible charge display. Notably, the stapled Tat peptides showed increased endosomal escape, high proteolytic stability, and low cytotoxicity. Therefore, they present a potent system for the intracellular transport of bioactive cargos.

Synthesis of NickFects, a New Family of CPPs, by Solid-Phase Peptide Synthesis.

Cell-penetrating peptides (CPPs) are relatively short peptides that can enter to the cell interior and facilitate intracellular delivery of associated cargo molecules. NickFects is a novel family of CPPs, designed to deliver various types of bio-active cargos using non-covalent nanoparticle formation approach. This chapter describes in details the manual synthesis of cell-penetrating peptides using Fmoc-solid phase peptide synthesis (SPPS).

Stimuli-Responsive Hydrogels with Antibacterial Activity Assembled from Guanosine, Aminoglycoside, and a Bifunctional Anchor.

Multistimuli-responsive hydrogels with specific functions have attracted great interest for biomedical applications; however, these smart hydrogels usually require the presynthesis of macromolecular building blocks with multiple ligands and the integration of bioactive cargoes into the gels. Here, a multistimuli-responsive hydrogel with potent antibacterial activity by a combination of supramolecular assembly and iminoboronate chemistry is reported. The hydrogel consists of all-small-molecule building blocks including aminoglycoside, guanosine, potassium ion, and a bifunctional anchor bearing both boronic acid and aldehyde groups. Guanosines form quadruplexes in the presence of potassium ions via supramolecular assembly, and the bifunctional anchor connects aminoglycosides, a class of potent antibiotics to cis-diol groups on quadruplexes via dynamic iminoboronate chemistry, yielding a smart hydrogel containing abundant antibiotics. The hydrogel is sensitive to multistimuli such as heat, acids, oxidants, glucose and crown ether, which promote the release of antibiotics from the gels. Moreover, the prepared hydrogels show potent antibacterial activities both in vitro and in vivo. The results provide a new option to prepare antibacterial hydrogels with multistimuli responsiveness via facile chemistry using all-small-molecule building blocks.

Tumor-derived extracellular vesicles: molecular parcels that enable regulation of the immune response in cancer.

Extracellular vesicles (EVs) are a heterogeneous collection of membrane-bound vesicles released by cells that contain bioactive cargoes including proteins, lipids and nucleic acids. Multiple subpopulations of EVs have now been recognized and these include exosomes and microvesicles. EVs have been thought to facilitate intercellular and distal communication to bring about various processes that enable tumor progression and metastases. Here, we describe the current knowledge of the functional cargo contained within EVs, with a focus on tumor microvesicles, and review the emerging theory of how EVs support immune suppression in cancer.

Engineered nano-bio interfaces for intracellular delivery and sampling: Applications, agency and artefacts

Engineered nano-bio cellular interfaces bring together well-defined nanoscale material morphologies with organic living systems. These extraordinarily complex interfaces are set to produce radical advances in the life sciences, through fundamental research in the emerging multidisciplinary field of cellular nano-biotechnology. We examine the role of a particular class of nanostructured platform: vertically aligned nanowire (VA-NW) arrays. These arrays feature diverse nanoscale topographies that enable unprecedented manipulation of cell functions and processes in vivo , in situ and in vitro . While the platform still requires further optimisation, recent use of the arrays – for in vivo transfection, non-destructive intracellular sampling and to gain fundamental insights into cellular responses to extracellular topographic cues – effectively demonstrates the platforms’ potential. We review innovative applications that show the repertoire of VA-NW arrays as highly efficient, universal, scalable intracellular delivery and sampling platforms, which presage prospects for clinical translation. We analyse the mechanisms by which VA-NW arrays facilitate delivery of bioactive cargos, and discuss the state of current knowledge about effects of nanowire topography on the cell-nanowire interface.

Extracellular vesicles in chronic obstructive pulmonary disease (COPD).

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease characterised by chronic inflammation and significant airflow obstruction that is not fully reversible, and is one of the leading causes of morbidity and mortality worldwide. Extracellular vesicles (EVs) (including apoptotic bodies, microvesicles and exosomes) are small membrane-bound vesicles released by nearly all cell types and can be found in various bodily fluids including blood, sputum and urine. EVs are key mediators in cell-cell communication due to their ability to exchange information to recipient cells, influencing physiological and pathological conditions using their bioactive cargo (DNA, RNA, miRNA, proteins and other metabolites). Therefore the main aim of this review is to highlight recent evidence of the potential use of EVs as diagnostic and therapeutic biomarkers for COPD managements, as well as EVs potential role in COPD pathogenesis. As EVs have been under intense investigation as diagnostic and therapeutic biomarkers for lung disease, in relation to COPD, key studies have identified EVs as potential biomarkers to distinguish exacerbations from stable state, and to characterise COPD phenotypes. EVs are also linked to key inflammatory mediators in COPD progression. In addition, bacteria and their EV cargo influence the lung microenvironment. Further recent therapeutic approaches and advances have seen EVs bioengineered as novel drug delivery vehicles, which could potentially have clinical utility for lung diseases such as COPD.

Endothelial microvesicles carrying Src-rich cargo impair adherens junction integrity and cytoskeleton homeostasis.

AimsMicrovesicles (MVs) conduct intercellular communication and impact diverse biological processes by transferring bioactive cargos to other cells. We investigated whether and how endothelial production of MVs contribute to vascular dysfunction during inflammation.Methods and resultsWe measured the levels and molecular properties of endothelial-derived MVs (EC-MVs) from mouse plasma following a septic injury elicited by cecal ligation and puncture, as well as those from supernatants of cultured endothelial cells stimulated by inflammatory agents including cytokines, thrombin, and complement 5a. The mouse studies showed that sepsis caused a significant increase in total plasma vesicles and VE-cadherin+ EC-MVs compared to sham control. In cultured ECs, different inflammatory agents caused diverse patterns of EC-MV production and cargo contents. When topically applied to endothelial cells, EC-MVs induced a cytoskeleton-junction response characterized by myosin light chain phosphorylation, contractile fibre reorganization, VE-cadherin phosphorylation, and adherens junction dissociation, functionally measured as increased albumin transendothelial flux and decreased barrier resistance. The endothelial response was coupled with protein tyrosine phosphorylation promoted by MV cargo containing c-Src kinase, whereas MVs produced from c-Src deficient cells did not exert barrier-disrupting effects. Additionally, EC-MVs contribute to endothelial inflammatory injury by promoting neutrophil-endothelium adhesion and release of neutrophil extracellular traps containing citrullinated histones and myeloperoxidase, a response unaltered by c-Src knockdown.ConclusionEndothelial-derived microparticles cause endothelial barrier dysfunction by impairing adherens junctions and activating neutrophils. The signalling mechanisms underlying the endothelial cytoskeleton-junction response to EC-MVs involve protein phosphorylation promoted by MV cargo carrying c-Src. However, EC-MV-induced neutrophil activation was not dependent on c-Src.

An ARF6–Exportin-5 axis delivers pre-miRNA cargo to tumour microvesicles

Tumor-derived microvesicles (TMVs) comprise a class of extracellular vesicles released from tumor cells that are now understood to facilitate communication between the tumor and the surrounding microenvironment. Despite their significance, the regulatory mechanisms governing the trafficking of bioactive cargos to TMVs at the cell surface remain poorly defined. Here we describe a molecular pathway for the delivery of microRNA (miRNA) cargo to nascent TMVs involving the dissociation of a pre-miRNA/Exportin-5 complex from Ran-GTP following nuclear export, and its subsequent transfer to a cytoplasmic shuttle comprised of ARF6-GTP and GRP1. As such, ARF6 activation increases pre-miRNA cargo contained within TMVs via a process that requires casein kinase 2-mediated phosphorylation of Ran-GAP1. Further, TMVs were found to contain pre-miRNA processing machinery including Dicer and Argonaute 2, which allow for cell-free pre-miRNA processing within shed vesicles. These findings offer cellular targets to block the loading and processing of pre-miRNAs within TMVs.

Research progress of extracellular vesicles in hepatic fibrosis

Liver fibrosis is a pathophysiological process characterized by abnormal accumulation of connective tissues in the liver caused by chronic liver injuries, in which the activation and migration of hepatic stellate cells (HSCs) play a central role. Extracellular vesicles (EVs) are a class of nanoscale, bilayer lipid enveloped vesicles secreted by almost all cells. EVs are of great interest in liver pathology because they have been found to mediate the communication between cells and regulate cellular microenvironment via horizontal transfer of their cargoes. EVs carry bioactive cargoes including proteins, lipids and RNA molecules, and are involved in the activation of HSCs during liver fibrogenesis.