Near-Infrared Light Activated Formulation for the Spatially Controlled Release of CRISPR-Cas9 Ribonucleoprotein for Brain Gene Editing.

The CRISPR/Cas9 system has emerged as a promising platform for gene editing; however, the lack of an efficient and safe delivery system to introduce it into cells continues to hinder clinical translation. Here, we report a rationally designed gene-editing nanoparticle (NP) formulation for brain applications: an sgRNA:Cas9 ribonucleoprotein complex is immobilized on the NP surface by oligonucleotides that are complementary to the sgRNA. Irradiation of the formulation with a near-infrared (NIR) laser generates heat in the NP, leading to the release of the ribonucleoprotein complex. The gene-editing potential of the formulation was demonstrated in vitro at the single-cell level. The safety and gene editing of the formulation were also demonstrated in the brains of reporter mice, specifically in the subventricular zone after intracerebral administration and in the olfactory bulb after intranasal administration. The formulation presented here offers a new strategy for the spatially controlled delivery of the CRISPR system to the brain.

Small extracellular vesicles administered directly in the brain promote neuroprotection and decreased microglia reactivity in a stroke mouse model.

Herein, we investigate the bioactivity of small extracellular vesicles (sEVs), focusing on their local effect in the brain. sEVs from mononuclear cells (MNCs) showed superior effects in vitro to sEVs from mesenchymal stem cells (MSCs) and were able to promote neuroprotection and decrease microglia reactivity in a stroke mouse model.

Imaging platforms to dissect the in vivo communication, biodistribution and controlled release of extracellular vesicles.

Extracellular vesicles (EVs) work as communication vehicles, allowing the exchange of bioactive molecules (microRNAs, mRNAs, proteins, etc) between neighbouring and distant cells in the organism. EVs are thus important players in several physiological and pathological processes. Thus, it is critical to understand their role in cellular/organ communication to fully evaluate their biological, diagnosis and therapeutic potential. In addition, recent studies have explored the controlled release of EVs for regenerative medicine applications and thus the evaluation of their release profile is important to correlate with biological activity. Here, we give a brief introduction about EV imaging platforms in terms of their sensitivity, penetration depth, cost, and operational simplicity, followed by a discussion of different EV labelling processes with their advantages and limitations. Next, we cover the relevance of these imaging platforms to dissect the tropism and biological role of endogenous EVs. We also cover the relevance of imaging platforms to monitor the accumulation of exogenous EVs and their potential cellular targets. Finally, we highlight the importance of imaging platforms to investigate the release profile of EVs from different controlled systems.

Reconsidering the role of blood-brain barrier in Alzheimer's disease: From delivery to target.

The existence of a selective blood-brain barrier (BBB) and neurovascular coupling are two unique central nervous system vasculature features that result in an intimate relationship between neurons, glia, and blood vessels. This leads to a significant pathophysiological overlap between neurodegenerative and cerebrovascular diseases. Alzheimer's disease (AD) is the most prevalent neurodegenerative disease whose pathogenesis is still to be unveiled but has mostly been explored under the light of the amyloid-cascade hypothesis. Either as a trigger, bystander, or consequence of neurodegeneration, vascular dysfunction is an early component of the pathological conundrum of AD. The anatomical and functional substrate of this neurovascular degeneration is the BBB, a dynamic and semi-permeable interface between blood and the central nervous system that has consistently been shown to be defective. Several molecular and genetic changes have been demonstrated to mediate vascular dysfunction and BBB disruption in AD. The isoform ε4 of Apolipoprotein E is at the same time the strongest genetic risk factor for AD and a known promoter of BBB dysfunction. Low-density lipoprotein receptor-related protein 1 (LRP-1), P-glycoprotein, and receptor for advanced glycation end products (RAGE) are examples of BBB transporters implicated in its pathogenesis due to their role in the trafficking of amyloid-ß. This disease is currently devoid of strategies that change the natural course of this burdening illness. This unsuccess may partly be explained by our misunderstanding of the disease pathogenesis and our inability to develop drugs that are effectively delivered to the brain. BBB may represent a therapeutic opportunity as a target itself or as a therapeutic vehicle. In this review, we aim to explore the role of BBB in the pathogenesis of AD including the genetic background and detail how it can be targeted in future therapeutic research.

Antimicrobial Peptide-Tether Dressing Able to Enhance Wound Healing by Tissue Contact.

No effective therapeutic dressings are currently available in the market that can prevent bacterial infection and simultaneously promote skin regeneration in diabetic patients. The lack of re-epithelization, prevalence of inflammation, and high risk of infection are hallmarks of non-healing wounds. Here, we have evaluated the antimicrobial and pro-regenerative effect of a relatively non-leaching LL37 peptide immobilized in polyurethane (PU)-based wound dressings (PU-adhesive-LL37 dressing). The PU-adhesive-LL37 (63 µg LL37NPs/cm2) dressing killed Gram-positive and Gram-negative bacteria in human serum without inducing bacterial resistance after 16 antimicrobial test cycles in contrast to commercially available dressings with the capacity to release antimicrobial Ag ions. Importantly, type II diabetic mice (db/db mice) treated with the PU-adhesive-LL37 dressing for different periods of time (6 or 14 days) showed enhanced wound healing and re-epithelialization (i.e., high keratin 14/5 levels) and lower macrophage infiltration in the wounds compared to animals treated with PU. The wounds treated with PU-adhesive-LL37 dressings showed also low expression of pro-inflammatory cytokines such as TNF-α and IL6 after 6 days of treatment, indicating that they act as an anti-inflammatory dressing. Additionally, PU-adhesive-LL37 dressings do not induce acute inflammatory responses in the peripheral blood mononuclear cells (PBMCs) after 3 days of exposure, in contrast to controls. Taken together, PU-adhesive-LL37NP dressings might prevent the bacterial infections and facilitate wound healing by tissue contact, inducing re-epithelialization and anti-inflammatory processes in diabetic conditions.

Extracellular vesicles enriched with an endothelial cell pro-survival microRNA affects skin tissue regeneration.

Endothelial cell (EC) activity is essential for tissue regeneration in several (patho)physiological contexts. However, our capacity to deliver in vivo biomolecules capable of controlling EC fate is relatively limited. Here, we screened a library of microRNA (miR) mimics and identified 25 miRs capable of enhancing the survival of ECs exposed to ischemia-mimicking conditions. In vitro, we showed that miR-425-5p, one of the hits, was able to enhance EC survival and migration. In vivo, using a mouse Matrigel plug assay, we showed that ECs transfected with miR-425-5p displayed enhanced survival compared with scramble-transfected ECs. Mechanistically, we showed that miR-425-5p modulated the PTEN/PI3K/AKT pathway and inhibition of miR-425-5p target genes (DACH1, PTEN, RGS5, and VASH1) phenocopied the pro-survival. For the in vivo delivery of miR-425-5p, we modulated small extracellular vesicles (sEVs) with miR-425-5p and showed, in vitro, that miR-425-5p-modulated sEVs were (1) capable of enhancing the survival of ECs exposed to ischemia-mimic conditions, and (2) efficiently internalized by skin cells. Finally, using a streptozotocin-induced diabetic wound healing mouse model, we showed that, compared with miR-scrambled-modulated sEVs, topical administration of miR-425-5p-modulated sEVs significantly enhanced wound healing, a process mediated by enhanced vascularization and skin re-epithelialization.

Exogenous loading of miRNAs into small extracellular vesicles.

Small extracellular vesicles (sEVs), through their natural ability to interact with biological membranes and exploit endogenous processing pathways to convey biological information, are quintessential for the delivery of therapeutically relevant compounds, such as microRNAs (miRNAs) and proteins. Here, we used a fluorescently-labelled miRNA to quantify the efficiency of different methods to modulate the cargo of sEVs. Our results showed that, compared with electroporation, heat shock, permeation by a detergent-based compound (saponin) or cholesterol-modification of the miRNA, Exo-Fect was the most efficient method with > 50% transfection efficiency. Furthermore, qRT-PCR data showed that, compared with native sEVs, Exo-Fect modulation led to a > 1000-fold upregulation of the miRNA of interest. Importantly, this upregulation was observed for sEVs isolated from multiple sources. The modulated sEVs were able to delivery miR-155-5p into a reporter cell line, confirming the successful delivery of the miRNA to the target cell and, more importantly, its functionality. Finally, we showed that the membrane of Exo-Fect-loaded sEVs was altered compared with native sEVs and that enhanced the internalization of Exo-Fect-loaded sEVs within the target cells and decreased the interaction of those modulated sEVs with lysosomes.

Engineered extracellular vesicles as brain therapeutics.

Extracellular vesicles (EVs) are communication channels between different cell types in the brain, between the brain and the periphery and vice-versa, playing a fundamental role in physiology and pathology. The evidence that EVs might be able to cross the blood-brain barrier (BBB) make them very promising candidates as nanocarriers to treat brain pathologies. EVs contain a cocktail of bioactive factors, yet their content and surface can be further engineered to enhance their biological activity, stability and targeting ability. Native and engineered EVs have been reported for the treatment of different brain pathologies, although issues related to their modest accumulation and limited local therapeutic effect in the brain still need to be addressed. In this review, we cover the therapeutic applications of native and bioengineered EVs for brain diseases. We also review recent data about the interaction between EVs and the BBB and discuss the challenges and opportunities in clinical translation of EVs as brain therapeutics.

Therapeutic Nanoparticles for the Different Phases of Ischemic Stroke.

Stroke represents the second leading cause of mortality and morbidity worldwide. Ischemic strokes are the most prevalent type of stroke, and they are characterized by a series of pathological events prompted by an arterial occlusion that leads to a heterogeneous pathophysiological response through different hemodynamic phases, namely the hyperacute, acute, subacute, and chronic phases. Stroke treatment is highly reliant on recanalization therapies, which are limited to only a subset of patients due to their narrow therapeutic window; hence, there is a huge need for new stroke treatments. Nonetheless, the vast majority of promising treatments are not effective in the clinical setting due to their inability to cross the blood-brain barrier and reach the brain. In this context, nanotechnology-based approaches such as nanoparticle drug delivery emerge as the most promising option. In this review, we will discuss the current status of nanotechnology in the setting of stroke, focusing on the diverse available nanoparticle approaches targeted to the different pathological and physiological repair mechanisms involved in each of the stroke phases.

Dynamic Reconfiguration of Cluster-Tree Wireless Sensor Networks to Handle Communication Overloads in Disaster-Related Situations.

The development of flexible and efficient communication mechanisms is of paramount importance within the context of the Internet of Things (IoT) paradigm. IoT has been used for industrial, commercial, and residential applications, and the IEEE 802.15.4/ZigBee standard is one of the most suitable protocols for this purpose. This protocol is now frequently used to implement large-scale Wireless Sensor Networks (WSNs). In industrial settings, it is becoming increasingly common to deploy cluster-tree WSNs, a complex IEEE 802.15.4/ZigBee-based peer-to-peer network topology, to monitor and control critical processes such as those related to oil or gas, mining, or certain specific chemicals. The remote monitoring of critical events for hazards or disaster detection in large areas is a challenging issue, since the occurrence of events in the monitored environment may severely stress the regular operation of the network. This paper proposes the Dynamic REconfiguration mechanism of cluster-Tree WSNs (DyRET), which is able to dynamically reconfigure large-scale IEEE 802.15.4 cluster-tree WSNs, and to assign communication resources to the overloaded branches of the tree based on the accumulated network load generated by each of the sensor nodes. A complete simulation assessment demonstrates the proposed mechanism's efficiency, and the results show that it can guarantee the required quality of service level for the dynamic reconfiguration of cluster-tree networks.

A near infrared light-triggerable modular formulation for the delivery of small biomolecules.

BACKGROUND: Externally triggered drug delivery systems hold considerable promise for improving the treatment of many diseases, in particular, diseases where the spatial-temporal release of the drug is critical to maximize their biological effect whilst minimizing undesirable, off-target, side effects. RESULTS: Herein, we developed a light-triggerable formulation that takes advantage of host-guest chemistry to complex drugs functionalized with a guest molecule and release it after exposure to near infrared (NIR) light due to the disruption of the non-covalent host-guest interactions. The system is composed by a gold nanorod (AuNR), which generates plasmonic heat after exposure to NIR, a thin layer of hyaluronic acid immobilized to the AuNR upon functionalization with a macrocycle, cucurbit[6]uril (CB[6]), and a drug functionalized with a guest molecule that interacts with the macrocycle. For proof of concept, we have used this formulation for the intracellular release of a derivative of retinoic acid (RA), a molecule known to play a key role in tissue development and homeostasis as well as during cancer treatment. We showed that the formulation was able to conjugate approximately 65 µg of RA derivative per mg of CB[6] @AuNR and released it within a few minutes after exposure to a NIR laser. Importantly, the bioactivity of RA released from the formulation was demonstrated in a reporter cell line expressing luciferase under the control of the RA receptor. CONCLUSIONS: This NIR light-triggered supramolecular-based modular platform holds great promise for theranostic applications.

The Kinetics of Small Extracellular Vesicle Delivery Impacts Skin Tissue Regeneration.

Small extracellular vesicles (SEVs) offer a promising strategy for tissue regeneration, yet their short lifetime at the injured tissue limits their efficacy. Here, we show that kinetics of SEV delivery impacts tissue regeneration at tissue, cellular, and molecular levels. We show that multiple carefully timed applications of SEVs had superior regeneration than a single dose of the same total concentration of SEVs. Importantly, diabetic and non-diabetic wounds treated with a single time point dose of an injectable light-triggerable hydrogel containing SEVs demonstrated a robust increase in closure kinetics relative to wounds treated with a single or multiple doses of SEVs or platelet-derived growth factor BB, an FDA-approved wound regenerative therapy. The pro-healing activity of released SEVs was mediated at the tissue/cell level by an increase in skin neovascularization and re-epithelization and at the molecular level by an alteration in the expression of 7 miRNAs at different times during wound healing. This includes an alteration of has-miR-150-5p, identified here to be important for skin regeneration.

A positron-emission tomography (PET)/magnetic resonance imaging (MRI) platform to track in vivo small extracellular vesicles.

Here we report a two-step surface modification methodology to radiolabel small extracellular vesicles (SEVs) with 64CuCl2 for PET/MRI imaging. The modification did not change or damage the morphology, surface receptor proteins and internal RNA content. Radiolabeled SEVs could be detected in organs with low accumulation such as the brain (0.4-0.5% ID g-1) and their brain location determined by MRI.

Modulation of Angiogenic Activity by Light-Activatable miRNA-Loaded Nanocarriers.

The combinatorial delivery of miRNAs holds great promise to modulate cell activity in the context of angiogenesis. Yet, the delivery of multiple miRNAs with spatiotemporal control remains elusive. Here, we report a plasmonic nanocarrier to control the release of two microRNAs. The nanocarrier consists of gold nanorods modified with single-stranded DNA for hybridization with complementary DNA-conjugated microRNAs. DNA strands with distinct melting temperatures enable the independent release of each microRNA with a near-infrared laser using the same wavelength but different powers. Tests in human outgrowth endothelial cells (OECs) indicate that this system can be used to silence different targets sequentially and, by doing so, to modulate cell activity with spatiotemporal resolution. Finally, using an in vivo acute wound healing animal model, it is demonstrated that the order by which each miRNA was released in transplanted OECs significantly impacted the wound healing kinetics.

Nanoparticles Conjugated with Photocleavable Linkers for the Intracellular Delivery of Biomolecules.

We report the synthesis and characterization of phototriggerable polymeric nanoparticles (NPs) for the intracellular delivery of small molecules and proteins to modulate cell activity. For that purpose, several photocleavable linkers have been prepared providing diverse functional groups as anchoring points for biomolecules.

Light-triggerable formulations for the intracellular controlled release of biomolecules.

New therapies based on the use of biomolecules [e.g., proteins, peptides, and non-coding (nc)RNAs] have emerged during the past few years. Given their instability, adverse effects, and limited ability to cross cell membranes, delivery systems are required to fully reveal their biological potential. Sophisticated nanoformulations responsive to light offer an excellent opportunity for the controlled release of these biomolecules, enabling the control of timing, duration, location, and dosage. In this review, we discuss the design principles for the delivery of biomolecules, in particular proteins and RNA-based therapeutics, by light-triggerable formulations. We further discuss the opportunities offered by these formulations in terms of endosomal escape, as well as their limitations.

Intracellular delivery of more than one protein with spatio-temporal control.

Transient, non-integrative modulation of cell function by intracellular delivery of proteins has high potential in cellular reprogramming, gene editing and therapeutic medicine applications. Unfortunately, the capacity to deliver multiple proteins intracellularly with temporal and spatial control has not been demonstrated. Here, we report a near infrared (NIR) laser-activatable nanomaterial that allows for precise control over the release of two proteins from a single nanomaterial. The nanomaterial is formed by gold nanorods (AuNRs) modified with single stranded DNA (ssDNA) to which complementary DNA-conjugated proteins are hybridized. Using DNA strands with distinct melting temperatures we are able to control independently the release of each protein with a laser using the same wavelength but with different powers. Studies in mammalian cells show that AuNRs conjugated with proteins are internalized by endocytosis and NIR laser irradiation promotes endosomal escape and the release of the proteins from the AuNRs simultaneously. Our results further demonstrate the feasibility of protein release from a carrier that has been accumulated within the cell up to 1 day while maintaining its activity.

Antifungal activity of dental resins containing amphotericin B-conjugated nanoparticles.

OBJECTIVES: To evaluate the antifungal activity, biocompatibility and mechanical properties of dental resins containing silica nanoparticles functionalized with amphotericin B (SNP-DexOxAmB) against five species of Candida. METHODS: Dental resin composites (Spectrum, Dentsply DeTrey, GmbH, Germany) having 2% (w/w) of SNP-DexOxAmB (SNPs of 5 and 80nm, denoted as SNP5 and SNP80) were aged for 10, 20 and 30 days at 37°C, in phosphate buffer saline buffer pH 7.4 (PBS). At different time, the antifungal activity was evaluated by a direct contact assay against 1×10(4)cells of Candida. The biocompatibility of the resins was tested against human fibroblasts, endothelial cells and red blood cells. RESULTS: Dental resins containing SNP5-DexOxAmB have high (1×10(4)cells killed in 5h by ∼70mg of dental resin composite containing 2% (w/w) of SNP-DexOxAmB) and durable (for at least 1 month) antifungal activity against five strains of Candida. The incorporation of the nanoparticles (NPs) had no significant change in the mechanical properties of the resin, specifically the flexural strength and modulus. Our results further show that the antifungal activity is mainly mediated by direct contact and not by leaching of NPs from the resin. Resins incorporating SNP5-DexOxAmB have longer-term antifungal activity than SNP80-DexOxAmB. The antimicrobial activity of resins with SNP5-DexOxAmB persists after 4 cycles of re-use and it is superior to the activity obtained for dental resins containing silver NPs. In addition, dental resins incorporating SNP5-DexOxAmB are non-cytotoxic against human skin fibroblasts and human umbilical vein endothelial cells, and non-hemolytic against human red blood cells. SIGNIFICANCE: The incorporation of SNP5-DexOxAmB in dental resins resulted in a non-cytotoxic composite with high and durable antifungal activity.

Differential internalization of amphotericin B--conjugated nanoparticles in human cells and the expression of heat shock protein 70.

Although a variety of nanoparticles (NPs) functionalized with amphotericin B, an antifungal agent widely used in the clinic, have been studied in the last years their cytotoxicity profile remains elusive. Here we show that human endothelial cells take up high amounts of silica nanoparticles (SNPs) conjugated with amphotericin B (AmB) (SNP-AmB) (65.4 ± 12.4 pg of Si per cell) through macropinocytosis while human fibroblasts internalize relatively low amounts (2.3 ± 0.4 pg of Si per cell) because of their low capacity for macropinocytosis. We further show that concentrations of SNP-AmB and SNP up to 400 µg/mL do not substantially affect fibroblasts. In contrast, endothelial cells are sensitive to low concentrations of NPs (above 10 µg/mL), in particular to SNP-AmB. This is because of their capacity to internalize high concentration of NPs and high sensitivity of their membrane to the effects of AmB. Low-moderate concentrations of SNP-AmB (up to 100 µg/mL) induce the production of reactive oxygen species (ROS), LDH release, high expression of pro-inflammatory cytokines and chemokines (IL-8, IL-6, G-CSF, CCL4, IL-1ß and CSF2) and high expression of heat shock proteins (HSPs) at gene and protein levels. High concentrations of SNP-AmB (above 100 µg/mL) disturb membrane integrity and kill rapidly human cells (60% after 5 h). This effect is higher in SNP-AmB than in SNP.