Electroactive 4D Porous Scaffold Based on Conducting Polymer as a Responsive and Dynamic In Vitro Cell Culture Platform

In vivo, cells reside in a 3D porous and dynamic microenvironment. It provides biochemical and biophysical cues that regulate cell behavior in physiological and pathological processes. In the context of fundamental cell biology research, tissue engineering, and cell-based drug screening systems, a challenge is to develop relevant in vitro models that could integrate the dynamic properties of the cell microenvironment. Taking advantage of the promising high internal phase emulsion templating, we here designed a polyHIPE scaffold with a wide interconnected porosity and functionalized its internal 3D surface with a thin layer of electroactive conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) to turn it into a 4D electroresponsive scaffold. The resulting scaffold was cytocompatible with fibroblasts, supported cellular infiltration, and hosted cells, which display a 3D spreading morphology. It demonstrated robust actuation in ion- and protein-rich complex culture media, and its electroresponsiveness was not altered by fibroblast colonization. Thanks to customized electrochemical stimulation setups, the electromechanical response of the polyHIPE/PEDOT scaffolds was characterized in situ under a confocal microscope and showed 10% reversible volume variations. Finally, the setups were used to monitor in real time and in situ fibroblasts cultured into the polyHIPE/PEDOT scaffold during several cycles of electromechanical stimuli. Thus, we demonstrated the proof of concept of this tunable scaffold as a tool for future 4D cell culture and mechanobiology studies.

Development and qualification of clinical grade decellularized and cryopreserved human esophagi

Tissue engineering is a promising alternative to current full thickness circumferential esophageal replacement methods. The aim of our study was to develop a clinical grade Decellularized Human Esophagus (DHE) for future clinical applications. After decontamination, human esophagi from deceased donors were placed in a bioreactor and decellularized with sodium dodecyl sulfate (SDS) and ethylendiaminetetraacetic acid (EDTA) for 3 days. The esophagi were then rinsed in sterile water and SDS was eliminated by filtration on an activated charcoal cartridge for 3 days. DNA was removed by a 3-hour incubation with DNase. A cryopreservation protocol was evaluated at the end of the process to create a DHE cryobank. The decellularization was efficient as no cells and nuclei were observed in the DHE. Sterility of the esophagi was obtained at the end of the process. The general structure of the DHE was preserved according to immunohistochemical and scanning electron microscopy images. SDS was efficiently removed, confirmed by a colorimetric dosage, lack of cytotoxicity on Balb/3T3 cells and mesenchymal stromal cell long term culture. Furthermore, DHE did not induce lymphocyte proliferation in-vitro. The cryopreservation protocol was safe and did not affect the tissue, preserving the biomechanical properties of the DHE. Our decellularization protocol allowed to develop the first clinical grade human decellularized and cryopreserved esophagus.

Targeting cell-derived markers to improve the detection of invisible biological traces for the purpose of genetic-based criminal identification

At a crime scene, investigators are faced with a multitude of traces. Among them, biological traces are of primary interest for the rapid genetic-based identification of individuals. "Touch DNA" consists of invisible biological traces left by the simple contact of a person's skin with objects. To date, these traces remain undetectable with the current methods available in the field. This study proposes a proof-of-concept for the original detection of touch DNA by targeting cell-derived fragments in addition to DNA. More specifically, adhesive-structure proteins (laminin, keratin) as well as carbohydrate patterns (mannose, galactose) have been detected with keratinocyte cells derived from a skin and fingermark touch-DNA model over two months in outdoor conditions. Better still, this combinatory detection strategy is compatible with DNA profiling. This proof-of-concept work paves the way for the optimization of tools that can detect touch DNA, which remains a real challenge in helping investigators and the delivery of justice.

Introduction of constrained Trp analogs in RW9 modulates structure and partition in membrane models

Over the past decades, many cell-penetrating peptides (CPP) have been studied for their capacity to cross cellular membranes, mostly in order to improve cellular uptake of therapeutic agents. Even though hydrophobic and anionic CPPs have been described, many of them are polycationic, due to the presence of several arginine (Arg) residues. Noteworthy, however, the presence of aromatic amino acids such as tryptophan (Trp) within CPPs seems to play an important role to reach high membranotropic activity. RW9 (RRWWRRWRR) is a designed CPP derived from the polyarginine R9 presenting both features. In general, when interacting with membranes, CPPs adopt an optimal conformation for membrane interactions - an amphipathic helical secondary structure in the case of RW9. Herein, we assumed that the incorporation of a locally constrained amino acid in the peptide sequence could improve the membranotropic activity of RW9, by facilitating its structuration upon contact with a membrane, while leaving a certain plasticity. Therefore, two cyclized Trp derivatives (Tcc and Aia) were synthesized to be incorporated in RW9 as surrogates of Trp residues. Thus, a series of peptides containing these building blocks has been synthesized by varying the type, position, and number of modifications. The membranotropic activity of the RW9 analogs was studied by spectrofluorescence titration of the peptides in presence of liposomes (DMPG), allowing to calculate partition coefficients (Kp). Our results indicate that the partitioning of the modified peptides depends on the type, the number and the position of the modification, with the best sequence being [Aia4]RW9. Interestingly, both NMR analysis and molecular dynamic (MD) simulations indicate that this analog presents an extended conformation similar to the native RW9, but with a much-reduced structural flexibility. Finally, cell internalization properties were also confirmed by confocal microscopy.

Poly-L-Lysine and Human Plasmatic Fibronectin Films as Proactive Coatings to Improve Implant Biointegration

The success of stable and long-term implant integration implies the promotion, control, and respect of the cell microenvironment at the site of implantation. The key is to enhance the implant–host tissue cross talk by developing interfacial strategies that guarantee an optimal and stable seal of soft tissue onto the implant, while preventing potential early and late infection. Indeed, implant rejection is often jeopardized by lack of stable tissue surrounding the biomaterial combined with infections which reduce the lifespan and increase the failure rate of implants and morbidity and account for high medical costs. Thin films formed by the layer-by-layer (LbL) assembly of oppositely charged polyelectrolytes are particularly versatile and attractive for applications involving cell–material contact. With the combination of the extracellular matrix protein fibronectin (Fn, purified from human plasma) and poly-L-lysine (PLL, exhibiting specific chain lengths), we proposed proactive and biomimetic coatings able to guarantee enhanced cell attachment and exhibiting antimicrobial properties. Fn, able to create a biomimetic interface that could enhance cell attachment and promote extracellular cell matrix remodeling, is incorporated as the anionic polymer during film construction by the LbL technic whereas PLL is used as the cationic polymer for its capacity to confer remarkable antibacterial properties.

Polymer-Based Honeycomb Films on Bioactive Glass: Toward a Biphasic Material for Bone Tissue Engineering Applications

The development of innovative materials for bone tissue engineering to promote bone regeneration while avoiding fibrous tissue infiltration is of paramount importance. Here, we combined the known osteopromotive properties of bioactive glasses (BaGs) with the biodegradability, biocompatibility, and ease to shape/handle of poly-l-co-d,l-lactic acid (PLDLA) into a single biphasic material. The aim of this work was to unravel the role of the surface chemistry and topography of BaG surfaces on the stability of a PLDLA honeycomb membrane, in dry and wet conditions. The PLDLA honeycomb membrane was deposited using the breath figure method (BFM) on the surface of untreated BaG discs (S53P4 and 13-93B20), silanized with 3-aminopropyltriethoxysilane (APTES) or conditioned (immersed for 24 h in TRIS buffer solution). The PLDLA membranes deposited onto the BaG discs, regardless of their composition or surface treatments, exhibited a honeycomb-like structure with pore diameter ranging from 1 to 5 μm. The presence of positively charged amine groups (APTES grafting) or the precipitation of a CaP layer (conditioned) significantly improved the membrane resistance to shear as well as its stability upon immersion in the TRIS buffer solution. The obtained results demonstrated that the careful control of the substrate surface chemistry enabled the deposition of a stable honeycomb membrane at their surface. This constitutes a first step toward the development of new biphasic materials enabling osteostimulation (BaG) while preventing migration of fibrous tissue inside the bone defect (honeycomb polymer membrane).

Development and characterization of a PLGA-HA composite material to fabricate 3D-printed scaffolds for bone tissue engineering

Additive manufacturing is a rising field in bone tissue engineering. Additive fabrication offers reproducibility, high precision and rapid manufacture of custom patient-specific scaffolds. The development of appropriate composite materials for biomedical applications is critical to reach clinical application of these novel biomaterials. In this work, medical grade poly(lactic-co-glycolic) acid (PLGA) was mixed with hydroxyapatite nanoparticles (nHA) to fabricate 3D porous scaffolds by Fused Deposition Modeling. We have first confirmed that the composite material could be printed in a reproductive manner. Physical characterization demonstrated a low degradation of the material during manufacturing steps and an expected loading and homogeneous distribution of nHA. In vitro biodegradation of the scaffolds showed modifications of morphological and physicochemical properties over time. The composite scaffolds were biocompatible and high cell viability was observed in vitro, as well as a maintain of cell proliferation. As expected, the addition of nHA displayed a positive impact on osteodifferentiation in vitro. Furthermore, a limited inflammatory reaction was observed after subcutaneous implantation of the materials in the rat. Overall, this study suggests that this composite material is suitable for bone tissue engineering applications.

Properties of interpenetrating polymer networks associating fibrin and silk fibroin networks obtained by a double enzymatic method

Fibrin gels are of interest as biomaterials for regenerative medicine but present poor mechanical properties, undergo fast degradation and strongly contract in presence of cells. To face these drawbacks, a fibrin network can be associated with another polymer network, in an Interpenetrating Polymer Network (IPN) architecture. In this study, we report the properties of an IPN comprising a fibrin (Fb) network and a silk fibroin (SF) network. This IPN is synthesized through the action of 2 enzymes, each one being specific of one protein gelation, i.e. thrombin (Tb) for Fb gelation, and horseradish peroxidase (HRP) for SF gelation. The effective formation of both Fb and SF networks in an IPN architecture was first verified at qualitative and quantitative levels. The resulting IPN was easily manipulable, displayed high viscoelastic properties and showed homogeneous macro- and micro-structure. Then the degradability of the IPN by two proteases, thermolysin (TL) and trypsin (TRY), obeying different mechanisms was presented. Finally, two-dimensional culture of human fibroblasts on the IPN surface induced little material contraction, while fibroblasts showed healthy morphology, displayed high viability and produced mature extracellular matrix (ECM) proteins. Taken together, the results suggest that this new IPN have a strong potential for tissue engineering and regenerative medicine.

Vitronectin (Vn) glycosylation patterned by lectin affinity assays-A potent glycoproteomic tool to discriminate plasma Vn from cancer ascites Vn

Changes in glycosylation have been associated with human cancer, but their complexity poses an analytical challenge. Ovarian cancer is a major cause of death in women because of an often late diagnosis. At least one-third of patients presents ascites fluid at diagnosis, and almost all have ascites at recurrence. Vitronectin (Vn) is a multifunctional glycoprotein that is suggested to be implicated in ovarian cancer metastasis and is found within ascites. The present study evaluated the potential of using lectin affinity for characterizing the glycosylation pattern of Vn. Human Vn was purified from 1 sample of ovarian cancer ascites or a pool of plasma samples. Consistent findings were observed with both dot blot and lectin array assays. Based on a panel of 40 lectins, the lectin array revealed discriminant patterns of lectin binding to Vn glycans. Interestingly, almost all the highlighted interactions were found to be higher with Vn from ascites relative to the plasma counterpart. Also, the lectin array was able to discriminate profiles of lectin interactions (ConA, SNA-I, PHA-E, PHA-L) between Vn samples that were not evident using dot blot, indicating its high sensitivity. The model of ConA binding during thermal unfolding of Vn confirmed the higher accessibility of mannosylated glycans in Vn from ascites as monitored by turbidimetry. Thus, this study demonstrated the usefulness of lectins and the lectin array as a glycoproteomic tool for high throughput and sensitive analysis of glycosylation patterns. Our data provide novel insights concerning Vn glycosylation patterns in clinical specimens, paving the way for further investigations regarding their functional impact and clinical interest.

Amyloid-like aggregates formation by blood plasma fibronectin

Fibronectin (FN) is a multifunctional glycoprotein of the extracellular matrix (ECM) playing critical roles in physiological and pathological cell processes like adhesion, migration, growth, and differentiation. These various functions of FN are modulated by its supramolecular state. Indeed, FN can polymerize into different types of assemblies like fibrils and aggregates. However, the mechanism of polymerization and the effects of such assemblies on cell behaviors still remain to be elucidated. Here we show that upon irreversible thermal denaturation, human blood plasma fibronectin forms high molecular weight aggregates. These compact and globular aggregates show amyloid features: they are stabilized by intermolecular b-sheets, they bind Thioflavin T and they are resistant to reducing and denaturing agents. Their characterization by electrospray ionization charge detection mass spectrometry shows that two populations can be distinguished according to the mass and charge density. Despite their amyloid features and the presence of hydrophobic patches on their surface, these aggregates are not toxic for cells. However, their binding abilities to gelatin and RGD are drastically decreased compare to native FN, suggesting possible effects on ECM-cell interactions.

Application of APTES-Anti-E-cadherin film for early cancer monitoring

Cancer staging is a way to classify cancer according to the extent of the disease in the body. The stage is usually determined by several factors such as the location of the primary tumor, the tumor size, the degree of spread in the surrounding tissues, etc. The study of E-cadherin (EC) expression on cancerous cells of patients has revealed variations in the molecular expression patterns of primary tumors and metastatic tumors. The detection of these cells requires a long procedure involving conventional techniques, thus, the requirement for development of new rapid devices that permit direct and highly sensitive detection stimulates the sensing field progress. Here, we explore if E-cadherin could be used as a biomarker to bind and detect epithelial cancer cells. Hence, the sensitive and specific detection of E-cadherin expressed on epithelial cells is approached by immobilizing anti-E-cadherin antibody (AEC) onto aminosilanized indium-tin oxide (ITO) surface. The immunosensing surfaces have been characterized by electrochemical measurements, wettability and confocal microscopy and their performance has been assessed in the presence of cancer cell lines. Under optimal conditions, the resulting immunosensor displayed a selective detection of E-cadherin expressing cells, which could be detected either by fluorescence or electrochemical techniques. The developed immunosensing surface could provide a simple tool that can be applied to cancer staging.

Ovarian cancer ascites-derived vitronectin and fibronectin: combined purification, molecular features and effects on cell response

BACKGROUND

Intra-abdominal ascites is a complication of ovarian cancers and constitutes a permissive microenvironment for metastasis. Since fibronectin and vitronectin are key actors in ovarian cancer progression, we investigated their occurrence and molecular characteristics in various ascites fluids and the influence of these ascites-derived proteins on cell behavior.

METHODS

Fibronectin and vitronectin were investigated by immunoblotting within various ascites fluids. A combined affinity-based protocol was developed to purify both proteins from the same sample. Each purified protein was characterized with regard to its molecular features (molecular mass of isoforms, tryptophan intramolecular environment, hydrodynamic radii), and its influence on cell adhesion.

RESULTS

Fibronectin and vitronectin were found in all tested ascites. Several milligrams of purified proteins were obtained from ascites of varying initial volumes. Molecular mass isoforms and conformational lability of proteins differed according to the ascites of origin. When incorporated into the cancer cell environment, ascites-derived fibronectin and vitronectin supported cell adhesion and migration with various degrees of efficiency, and induced the recruitment of integrins into focal contacts.

CONCLUSIONS

To our knowledge, this is the first combined purification of two extracellular matrix proteins from a single pathological sample containing a great variety of bioactive molecules. This study highlights that ascites-derived fibronectin and vitronectin exhibit different properties depending on the ascites.

GENERAL SIGNIFICANCE

Investigating the relationships between the molecular properties of ascites components and ovarian cancer cell phenotype according to the ascites may be critical for a better understanding of the recurrence of this lethal disease and for further biomarker identification.

Reduction of Escherichia coli adherence to uroepithelial bladder cells after consumption of cranberry juice: a double-blind randomized placebo-controlled cross-over trial

To determine the efficacy of the consumption of cranberry juice versus placebo with regard to the presence of in vitro bacterial anti-adherence activity in the urine of healthy volunteers. Twenty healthy volunteers, 10 men and 10 women, were included. The study was a double-blind, randomized, placebo-controlled, and cross-over study. In addition to normal diet, each volunteer received at dinner a single dose of 750 ml of a total drink composed of: (1) 250 ml of the placebo and 500 ml of mineral water, or (2) 750 ml of the placebo, or (3) 250 ml of the cranberry juice and 500 ml of mineral water, or (4) 750 ml of the cranberry juice. Each volunteer took the four regimens successively in a randomly order, with a washout period of at least 6 days between every change in regimen. The first urine of the morning following cranberry or placebo consumption was collected and used to support bacterial growth. Six uropathogenic Escherichia coli strains (all expressing type 1 pili; three positive for the gene marker for P-fimbriae papC and three negative for papC), previously isolated from patients with symptomatic urinary tract infections, were grown in urine samples and tested for their ability to adhere to the T24 bladder cell line in vitro. There were no significant differences in the pH or specific gravity between the urine samples collected after cranberry or placebo consumption. We observed a dose dependent significant decrease in bacterial adherence associated with cranberry consumption. Adherence inhibition was observed independently from the presence of genes encoding type P pili and antibiotic resistance phenotypes. Cranberry juice consumption provides significant anti-adherence activity against different E. coli uropathogenic strains in the urine compared with placebo.

Transmigration of human ovarian adenocarcinoma cells through endothelial extracellular matrix involves alphav integrins and the participation of MMP2

The growth of ovarian carcinoma is dependent upon their vascularistion, but the interaction of ovarian cancer cells with the endothelium and their invasion through an endothelial environment remain poorly understood at the molecular level. To investigate adhesive events underlying this process with focusing on the role of alphav integrins and MT1MMP-MMP2 proteinases, we used in vitro models of cocultures of human ovarian adenocarcinoma cell lines (IGROV1 and SKOV3) with human umbilical vein endothelial cells (HUVECs). Immunostaining of HUVECs revealed the network organisation of fibrillar fibronectin (Fn) and pericellular vitronectin (Vn). During coculture, IGROV1 and SKOV3 cells gain access to subendothelial basement membrane of HUVECs and dislocated endothelial Fn without affecting endothelial Vn. Transmigration assays revealed that tumour cells invade Vn and, with an higher efficiency, Fn. Our data also highlighted that ovarian carcinoma cells migrated through the Fn-rich HUVEC-ECM. The expression of MMP2 and MT1-MMP was revealed in tumour cells within an endothelial environment. Furthermore, we found that cell migration through the endothelial ECM was almost totally dependent on alphav integrin function, whereas beta1 integrins were not solicited. In addition, inhibitors of MMP2 activity (alone or combined with anti-alphav integrin MAb) or TSRI265 (which blocks MMP2-alphavbeta3 association) were found to impede this process. Finally, alphav integrins, MT1-MMP and MMP2 were found in ovarian carcinoma cells within the 3-dimensional architecture of intraperitoneal tumour nodes collected from nude mice xenografted with IGROV1 or SKOV3 cell lines or within human tumour tissues. alphav integrins therefore appear as essential to the migration properties of human ovarian carcinoma cells, especially in an endothelial environment, with MMP2 participating to this process.