Imaging Diffusion and Stability of Single-Chain Polymeric Nanoparticles in a Multi-Gel Tumor-on-a-Chip Microfluidic Device.

The performance of single-chain polymeric nanoparticles (SCPNs) in biomedical applications highly depends on their conformational stability in cellular environments. Until now, such stability studies are limited to 2D cell culture models, which do not recapitulate the 3D tumor microenvironment well. Here, a microfluidic tumor-on-a-chip model is introduced that recreates the tumor milieu and allows in-depth insights into the diffusion, cellular uptake, and stability of SCPNs. The chip contains Matrigel/collagen-hyaluronic acid as extracellular matrix (ECM) models and is seeded with cancer cell MCF7 spheroids. With this 3D platform, it is assessed how the polymer's microstructure affects the SCPN's behavior when crossing the ECM, and evaluates SCPN internalization in 3D cancer cells. A library of SCPNs varying in microstructure is prepared. All SCPNs show efficient ECM penetration but their cellular uptake/stability behavior depends on the microstructure. Glucose-based nanoparticles display the highest spheroid uptake, followed by charged nanoparticles. Charged nanoparticles possess an open conformation while nanoparticles stabilized by internal hydrogen bonding retain a folded structure inside the tumor spheroids. The 3D microfluidic tumor-on-a-chip platform is an efficient tool to elucidate the interplay between polymer microstructure and SCPN's stability, a key factor for the rational design of nanoparticles for targeted biological applications.

Advanced optical imaging for the rational design of nanomedicines.

Despite the enormous potential of nanomedicines to shape the future of medicine, their clinical translation remains suboptimal. Translational challenges are present in every step of the development pipeline, from a lack of understanding of patient heterogeneity to insufficient insights on nanoparticle properties and their impact on material-cell interactions. Here, we discuss how the adoption of advanced optical microscopy techniques, such as super-resolution optical microscopies, correlative techniques, and high-content modalities, could aid the rational design of nanocarriers, by characterizing the cell, the nanomaterial, and their interaction with unprecedented spatial and/or temporal detail. In this nanomedicine arena, we will discuss how the implementation of these techniques, with their versatility and specificity, can yield high volumes of multi-parametric data; and how machine learning can aid the rapid advances in microscopy: from image acquisition to data interpretation.

Identification of fluorescently-barcoded nanoparticles using machine learning.

Barcoding of nano- and micro-particles allows distinguishing multiple targets at the same time within a complex mixture and is emerging as a powerful tool to increase the throughput of many assays. Fluorescent barcoding is one of the most used strategies, where microparticles are labeled with dyes and classified based on fluorescence color, intensity, or other features. Microparticles are ideal targets due to their relative ease of detection, manufacturing, and higher homogeneity. Barcoding is considerably more challenging in the case of nanoparticles (NPs), where their small size results in a lower signal and greater heterogeneity. This is a significant limitation since many bioassays require the use of nano-sized carriers. In this study, we introduce a machine-learning-assisted workflow to write, read, and classify barcoded PLGA-PEG NPs at a single-particle level. This procedure is based on the encapsulation of fluorescent markers without modifying their physicochemical properties (writing), the optimization of their confocal imaging (reading), and the implementation of a machine learning-based barcode reader (classification). We found nanoparticle heterogeneity as one of the main factors that challenges barcode separation, and that information extracted from the dyes' nanoscale confinement effects (such as Förster Resonance Energy Transfer, FRET) can aid barcode identification. Moreover, we provide a guide to reaching the optimal trade-off between the number of simultaneous barcodes and classification accuracy supporting the use of this workflow for a variety of bioassays.

High Mobility Group Box 1 Release by Cholangiocytes Governs Biliary Atresia Pathogenesis and Correlates With Increases in Afflicted Infants.

BACKGROUND AND AIMS: Biliary atresia (BA) is a devastating cholangiopathy of infancy. Upon diagnosis, surgical reconstruction by Kasai hepatoportoenterostomy (HPE) restores biliary drainage in a subset of patients, but most patients develop fibrosis and progress to end-stage liver disease requiring liver transplantation for survival. In the murine model of BA, rhesus rotavirus (RRV) infection of newborn pups results in a cholangiopathy paralleling that of human BA. High-mobility group box 1 (HMGB1) is an important member of the danger-associated molecular patterns capable of mediating inflammation during infection-associated responses. In this study, we investigated the role of HMGB1 in BA pathogenesis. APPROACH AND RESULTS: In cholangiocytes, RRV induced the expression and release of HMGB1 through the p38 mitogen-activated protein kinase signaling pathway, and inhibition of p38 blocked HMGB1 release. Treatment of cholangiocytes with ethyl pyruvate suppressed the release of HMGB1. Administration of glycyrrhizin in vivo decreased symptoms and increased survival in the murine model of BA. HMGB1 levels were measured in serum obtained from infants with BA enrolled in the PROBE and START studies conducted by the Childhood Liver Disease Research Network. High HMGB1 levels were found in a subset of patients at the time of HPE. These patients had higher bilirubin levels 3 months post-HPE and a lower survival of their native liver at 2 years. CONCLUSIONS: These results suggest that HMGB1 plays a role in virus induced BA pathogenesis and could be a target for therapeutic interventions in a subset of patients with BA and high HMGB1.

Pharmacological inhibition of STAT3 pathway ameliorates acute liver injury in vivo via inactivation of inflammatory macrophages and hepatic stellate cells.

Liver diseases represent a major health problem worldwide, in particular, acute liver injury is associated with high mortality and morbidity. Inflammatory macrophages and hepatic stellate cells (HSCs) are known to be involved in the pathogenesis of acute liver injury. In this study, we have investigated the implication of STAT3 inhibition in acute liver injury/early fibrogenesis. In fibrotic human livers, we found STAT3 mRNA expression was significantly upregulated and correlated with collagen I expression. In vitro, STAT3 signaling pathway was found to be activated in TGFß-activated HSCs and inflammatory macrophages. STAT3 inhibitor, WP1066 significantly inhibited TGFß-induced collagen I, vimentin and α-SMA expression, and contractility in human HSCs. In LPS- and IFNγ-induced pro-inflammatory macrophages, WP1066 strongly attenuated nitric-oxide release and expression of major inflammatory markers such as TNF-α, iNOS, CCL2, IL-1ß, IL-6, and CCR2. In vivo in CCl4-induced acute liver injury mouse model, WP1066 significantly reduced collagen expression, HSCs activation, and intrahepatic inflammation. Finally, in LPS-induced human hepatic 3D spheroid model, WP1066 inhibited LPS-induced fibrotic and inflammatory parameters. In conclusion, our results demonstrate that the therapeutic inhibition of STAT3 pathway using WP1066 targeting HSCs and inflammatory macrophages suggests a potential pharmacological approach for the treatment of acute liver injury.

Innate Immunity and Pathogenesis of Biliary Atresia.

Biliary atresia (BA) is a devastating fibro-inflammatory disease characterized by the obstruction of extrahepatic and intrahepatic bile ducts in infants that can have fatal consequences, when not treated in a timely manner. It is the most common indication of pediatric liver transplantation worldwide and the development of new therapies, to alleviate the need of surgical intervention, has been hindered due to its complexity and lack of understanding of the disease pathogenesis. For that reason, significant efforts have been made toward the development of experimental models and strategies to understand the etiology and disease mechanisms and to identify novel therapeutic targets. The only characterized model of BA, using a Rhesus Rotavirus Type A infection of newborn BALB/c mice, has enabled the identification of key cellular and molecular targets involved in epithelial injury and duct obstruction. However, the establishment of an unleashed chronic inflammation followed by a progressive pathological wound healing process remains poorly understood. Like T cells, macrophages can adopt different functional programs [pro-inflammatory (M1) and resolutive (M2) macrophages] and influence the surrounding cytokine environment and the cell response to injury. In this review, we provide an overview of the immunopathogenesis of BA, discuss the implication of innate immunity in the disease pathogenesis and highlight their suitability as therapeutic targets.

TG101348, a selective JAK2 antagonist, ameliorates hepatic fibrogenesis in vivo.

Hepatic fibrosis, characterized by an excessive extracellular matrix (ECM) accumulation, leading to scar-tissue formation is a growing health problem worldwide. Hepatocellular damage due to liver injury triggers inflammation and transdifferentiation of quiescent hepatic stellate cells (HSCs) into proliferative, contractile, and ECM-producing myofibroblasts. Involvement of the Janus kinase (JAK)-2 pathway in the pathogenesis of fibrosis has been reported earlier. However, in this study, we have investigated the effect of selective JAK2 antagonist TG101348 in fibroblasts and inflammatory macrophages and in vivo in an acute carbon tetrachloride-induced liver injury mouse model. In vitro, TG101348 significantly inhibited TGF-ß-induced collagen I expression in murine 3T3 fibroblasts. In human HSCs (LX2 cells), TG101348 potently attenuated TGF-ß-induced contractility and the protein and gene expression of major fibrotic parameters (collagen I, vimentin, and α-smooth muscle actin). In LPS- and IFN-γ-stimulated inflammatory macrophages, TG101348 significantly reduced the NO release and strongly inhibited the expression of inflammatory markers (inducible nitric oxide synthase, C-C motif chemokine ligand 2, IL-1ß, IL-6, and C-C chemokine receptor type 2). In vivo in an acute liver injury mouse model, TG101348 significantly attenuated collagen accumulation and HSC activation. Interestingly, TG101348 drastically inhibited macrophage infiltration and intrahepatic inflammation. Pharmacological inhibition of the JAK2 signaling pathway in activated HSCs and inflammatory macrophages using TG101348 suggests a potential therapeutic approach for the treatment of liver fibrosis.-Akcora, B. O., Dathathri, E., Ortiz-Perez, A., Gabriël, A. V., Storm, G., Prakash, J., Bansal, R. TG101348, a selective JAK2 antagonist, ameliorates hepatic fibrogenesis in vivo.

Effects of Four Formulations of Prostaglandin Analogs on Eye Surface Cells. A Comparative Study.

We evaluated the cytotoxic effects of four prostaglandin analogs (PGAs) used to treat glaucoma. First we established primary cultures of conjunctival stromal cells from healthy donors. Then cell cultures were incubated with different concentrations (0, 0.1, 1, 5, 25, 50 and 100%) of commercial formulations of bimatoprost, tafluprost, travoprost and latanoprost for increasing periods (5 and 30 min, 1 h, 6 h and 24 h) and cell survival was assessed with three different methods: WST-1, MTT and calcein/AM-ethidium homodimer-1 assays. Our results showed that all PGAs were associated with a certain level of cell damage, which correlated significantly with the concentration of PGA used, and to a lesser extent with culture time. Tafluprost tended to be less toxic than bimatoprost, travoprost and latanoprost after all culture periods. The results for WST-1, MTT and calcein/AM-ethidium homodimer-1 correlated closely. When the average lethal dose 50 was calculated, we found that the most cytotoxic drug was latanoprost, whereas tafluprost was the most sparing of the ocular surface in vitro. These results indicate the need to design novel PGAs with high effectiveness but free from the cytotoxic effects that we found, or at least to obtain drugs that are functional at low dosages. The fact that the commercial formulation of tafluprost used in this work was preservative-free may support the current tendency to eliminate preservatives from eye drops for clinical use.