Cell-microenvironment Interactions Research Articles

Abstract Mo089: Fontan-Associated Liver Disease On A Chip

Introduction: The Fontan procedure is performed in children with single ventricle physiology, and has led to excellent short-term palliation and survival rates but at the cost of long-term complications. Fontan-associated liver disease (FALD) results from hemodynamic changes following the Fontan procedure, leading to elevated central venous pressures, chronic alterations in hepatic perfusion, and resultant hepatic fibrosis. Improved understanding of FALD pathophysiology, which may provide insights for prevention and treatment is challenged by the lack of experimental models. Current in vitro liver models, mostly 2D or suspension hepatic cell cultures, lack biomimicry. This study presents a 3D bioprinted perfusable human liver model for in vitro study of hepatic fibrosis in response to altered flow conditions in FALD patients. Methods: Vascular 3D model of hepatic sinusoid was biofabricated using hybrid bioinks in two distinct peripheral layers and a central lumen. The outer layer was cast with hepatic (HepG2) cells encapsulated in a mixture of gelatin methacrylate (GelMA) and collagen type I. The inner layer consisted of hepatic stellate cells (HSCs) in GelMA. Human endothelial cells (ECs) were seeded onto the central lumen. 3D cellular constructs were cultured in vitro for three weeks in static or dynamic conditions, by circulating the culture media at varying flow conditions to simulate sinusoid pressure characteristic of healthy vs. disease state. Using Volcano system in cath lab, we invasively measured the pressure in mid-channel. Cell viability, proliferation, maturation into functional liver tissue, and tissue stiffness were evaluated via microindentation, flow hemodynamics assays, metabolomic assays, and immunohistochemistry analyses. Results: Bioengineered liver constructs cultured under static and dynamic conditions demonstrated high cell viability and growth and full endothelialization of the sinusoid channel. HepG2 cells exhibited long-term function and maturation, forming clusters. Under FALD flow conditions, there were notable changes in EC-HepG2 cell morphology compared to dynamic flow in the healthy range, accompanied by reduced levels of functional markers. Conclusion: This proof-of-principle study introduces an innovative and highly biomimetic 3D model of hepatic sinusoid, which can serve as a robust platform for in vitro investigations of complex cell-microenvironment interactions in the context of FALD as well as other hepatic disorders.

A multicellular vessel-on-a-chip model reveals context-dependent roles for platelets in inflammation and inflammatory hemostasis

AbstractThe immune system identifies and destroys invading pathogens. However, chronic inflammation and excessive tissue damage can occur if inflammation is not resolved or if the immune system misidentifies a threat. Therefore, the immune system must be tightly controlled. However, the complex cell-cell and cell-microenvironment interactions that regulate immune-cell recruitment are challenging to recapitulate in 2-dimensional in vitro models, and poorly representative of human physiology in in vivo animal models. Organ-on-a-chip technology has the potential to overcome these limitations and provide powerful preclinical models. In this study, we developed a vessel-on-a-chip model to investigate the role of platelets in inflammation and inflammatory hemostasis. Endothelial vessels cultured in the OrganoPlate exhibited physiological barrier function to macromolecules and red blood cells (RBCs), which was enhanced by platelets. Cytokine stimulation increased vessel permeability and induced neutrophil transmigration. Leakage of RBCs occurred at sites of inflammation and/or neutrophil transmigration, depending on the extracellular matrix composition. Addition of platelets prevented RBC leakage at these sites, while simultaneously increasing permeability and neutrophil transmigration, demonstrating the multifaceted role of platelets in inflammatory hemostasis. In angiogenic neovessels, platelets played a protective role, preventing leakage of both small molecules and RBCs. Together, our model successfully recapitulated the modulation of endothelial barrier function and inflammation by platelets and demonstrated the feasibility of investigating complex cellular interactions in in vitro models.

Abstract 434: Understanding metabolic heterogeneity of estrogen receptor positive metastatic breast tumors using spatial transcriptomics and geographic information systems approaches

Abstract The tumor microenvironment consists of numerous cell populations showing diverse metabolic preferences, causing metabolic heterogeneity and therapy resistance. Fulvestrant, a clinically approved selective estrogen receptor (ER) degrader, is the standard of care for ER-positive breast cancer, yet resistance has been reported among metastatic breast cancer patients. In our previous studies, we showed such resistance is attributable to metabolic heterogeneity in the tumor microenvironment. Despite metabolic heterogeneity posing a common challenge in cancer research, current methods, such as histology and Magnetic Resonance Imaging, cannot explore nutrient uptake at transcript-level resolution with spatial context, making it difficult to understand the heterogeneity that affects cellular growth and metabolism. Visium Spatial Transcriptomics, a method that shows regional gene expression, is emerging as a powerful spatial analysis tool, and we integrated this method with geographic information systems to investigate the tumor microenvironment heterogeneity and highlight the importance of cell-microenvironment interactions. We developed a computational pipeline to visualize hotspots of spatially relevant genes using breast cancer metastatic samples from xenograft models and human patients. This pipeline integrates Visium tools and geospatial methods for processing transcriptome profiling data. We analyzed the degree of local spatial association based on Local Moran’s I to estimate regions with significant co-localization of single and multiple gene expressions within a tumor. We then leveraged the co-localized areas in the process of biomarker identification and revealing biological pathways. We also used unsupervised clustering of the complete transcriptome profiles to test the resemblance between identified clusters and hotspots as well as any disruption in the spatial structure of clusters in response to therapy or metastasis. Gene set enrichment analysis of these clusters revealed several glucose or lipid metabolism pathways, and mapping of the genes corresponding to each pathway showed mutually exclusive gene expression patterns in the sample. We also observed minimal co-localization of two metabolic pathways but extensive co-localization between metabolic genes and ER target genes, suggesting distinct metabolic preferences and spatial distributions of endocrine therapy resistant cell populations. Altogether, our analysis pipeline established a computational framework for characterizing the link between tumor microenvironment, local metabolism, and changes in transcriptional response to external stimuli. Our findings support the development of strategies to target different endocrine resistant regions using a combination of ER and metabolic signaling inhibitors. Citation Format: Jin Young Yoo, Sabrina Akter, Nandana Varma, Atharva Jain, Aiman Soliman, Zeynep Madak Erdogan. Understanding metabolic heterogeneity of estrogen receptor positive metastatic breast tumors using spatial transcriptomics and geographic information systems approaches [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 434.

Can vitamin D deficiency affect the development of cancer? - review of the literature

Introduction and purpose:
 Over recent years, there has been a noticeable increase in cases of cancer around the world. At the same time, there is the problem of vitamin D deficiency, which may affect up to one-quarter of the population. The aim of this article is to link these two epidemics and organize knowledge about vitamin D and its multidirectional effects related to many diseases, especially cancer.
 State of knowledge:
 Many scientific works have proven that vitamin D has a beneficial effect not only on the known calcium-phosphate metabolism. Researchers emphasize its pleiotropic effect on many organs and systems in the human body, and thus on many diseases, including cancer. Studies show that vitamin D modulates the expression of many different miRNAs specific to various types of cancer. The results of in vitro and in vivo studies showed the effect of calcitriol on cell growth and development. It influences processes such as differentiation, proliferation, apoptosis, strengthens the immune system, and reduces oxidative stress.
 Summary:
 Based on accumulated research, we can conclude that vitamin D presumably regulates the entire process of tumorigenesis, from initiation to metastasis and cell-microenvironment interactions. However, some studies do not confirm these data or provide contradictory results. For this reason, it is necessary to deepen research on this topic in order to establish specific recommendations, therapeutic and preventive plans. However, vitamin D and its role in the pathogenesis of many diseases should not be underestimated. In cases of low vitamin D concentration in the body, its supplementation will be reasonable, considering the functional identity of this source compared to sun exposure or diet.

Cancer Metastasis-on-a-Chip for Modeling Metastatic Cascade and Drug Screening.

Microfluidic chips are valuable tools for studying intricate cellular and cell-microenvironment interactions. Traditional in vitro cancer models lack accuracy in mimicking the complexities of in vivo tumor microenvironment. However, cancer-metastasis-on-a-chip (CMoC) models combine the advantages of 3D cultures and microfluidic technology, serving as powerful platforms for exploring cancer mechanisms and facilitating drug screening. These chips are able to compartmentalize the metastatic cascade, deepening the understanding of its underlying mechanisms. This article provides an overview of current CMoC models, focusing on distinctive models that simulate invasion, intravasation, circulation, extravasation, and colonization, and their applications in drug screening. Furthermore, challenges faced by CMoC and microfluidic technologies are discussed, while exploring promising future directions in cancer research. The ongoing development and integration of these models into cancer studies are expected to drive transformative advancements in the field.

THU500 Geospatial Analysis To Quantify Spatial Heterogeneity Of Tumor Microenvironment

Abstract Disclosure: J. Yoo: None. C. Mitra: None. Y. Yue: None. A. Soliman: None. Z. Madak Erdogan: None. Metabolic heterogeneity, a concept describing distinct differences in nutrient metabolism within the cells of a healthy or diseased tissue, is a common challenge in development and cancer research. Current methods, such as histology and Magnetic Resonance Imaging (MRI), cannot visualize nutrient uptake into single cells, making it difficult to understand the heterogeneity that affects cellular growth and metabolism. Visium Spatial Transcriptomics, a method that shows regional gene expression, is emerging as a powerful spatial analysis tool, and we aim to integrate this transcriptomic method with other biologically relevant datasets to highlight the importance of cell-microenvironment interactions. We propose to leverage geostatistical tools to model the multivariate covariance structure of genes expression profiles to allow: 1) understanding of their spatial characteristics and covariance changes under certain conditions (e.g. drug treatment or damage), 2) using these covariance structures to simulate synthetic samples at a scale sufficient to train the state of art neural network architectures, and 3) incorporating spatial awareness directly in the machine learning/deep learning models by enriching the spatial transcriptomics data using distance proximity functions. We will quantify the tumor microenvironment spatial heterogeneity using different approaches. First, we will analyze the degree of spatial auto-correlation to estimate the ranges of spatial heterogeneity within a tumor. We also plan to quantify the degree of anisotropy to identify if the tumor heterogeneity is happening along specific axis. Different local clustering indicators will be also calculated, such as the Getis-Ord (Gi*) statistic and Local Moran's I to identify the prevalence of hot and cold spots in the tumor. These hot and cold spots will be used to segment the tumor area into sub-regions and further quantify the local heterogeneity with a single tumor. We hypothesize that transcriptional heterogeneity reflects phenotypic differences in different regions of healthy or diseased tissue, rendering cells in certain regions to display a differential response to external stimuli (e.g. diet or drugs). Integration of multiple information (e.g. retrospective patient data) with different spatial heterogeneity indicators identified from the geospatial analyses could aid in identification of patients who are resistant to cancer therapies and further advance personalized therapy. Presentation: Thursday, June 15, 2023

Multifunctional Proximity Labeling Strategy for Lipid Raft-Specific Sialic Acid Tracking and Engineering.

Lipid raft-specific glycosylation has been implicated in many biological processes, including intracellular trafficking, cell adhesion, signal transduction, and host-pathogen interactions. The major predicament in lipid raft-specific glycosylation research is the unavailability of tools for tracking and manipulating glycans on lipid rafts at the microstructural level. To overcome this challenge, we developed a multifunctional proximity labeling (MPL) platform that relies on cholera toxin B subunit to localize horseradish peroxidase on lipid rafts. In addition to the prevailing electron-rich amino acids, modified sialic acid was included in the horseradish peroxidase-mediated proximity labeling substrate via purposefully designed chemical transformation reactions. In combination with sialic acid editing, the self-renewal of lipid raft-specific sialic acid was visualized. The MPL method enabled tracking of lipid raft dynamics under methyl-β-cyclodextrin and mevinolin treatments; in particular, the alteration of lipid rafts markedly affected cell migration. Furthermore, we embedded functional molecules into the method and implemented raft-specific sialic acid gradient engineering. Our novel strategy presents opportunities for tailoring lipid raft-specific sialic acids, thereby regulating interactions associated with lipid raft regions (such as cell-virus and cell-microenvironment interactions), and can aid in the development of lipid raft-based therapeutic regimens for tumors.

Controlled tumor heterogeneity in a co-culture system by 3D bio-printed tumor-on-chip model

Cancer treatment resistance is a caused by presence of various types of cells and heterogeneity within the tumor. Tumor cell–cell and cell-microenvironment interactions play a significant role in the tumor progression and invasion, which have important implications for diagnosis, and resistance to chemotherapy. In this study, we develop 3D bioprinted in vitro models of the breast cancer tumor microenvironment made of co-cultured cells distributed in a hydrogel matrix with controlled architecture to model tumor heterogeneity. We hypothesize that the tumor could be represented by a cancer cell-laden co-culture hydrogel construct, whereas its microenvironment can be modeled in a microfluidic chip capable of producing a chemical gradient. Breast cancer cells (MCF7 and MDA-MB-231) and non-tumorigenic mammary epithelial cells (MCF10A) were embedded in the alginate-gelatine hydrogels and printed using a multi-cartridge extrusion bioprinter. Our approach allows for precise control over position and arrangements of cells in a co-culture system, enabling the design of various tumor architectures. We created samples with two different types of cells at specific initial locations, where the density of each cell type was carefully controlled. The cells were either randomly mixed or positioned in sequential layers to create cellular heterogeneity. To study cell migration toward chemoattractant, we developed a chemical microenvironment in a chamber with a gradual chemical gradient. As a proof of concept, we studied different migration patterns of MDA-MB-231 cells toward the epithelial growth factor gradient in presence of MCF10A cells in different ratios using this device. Our approach involves the integration of 3D bioprinting and microfluidic devices to create diverse tumor architectures that are representative of those found in various patients. This provides an excellent tool for studying the behavior of cancer cells with high spatial and temporal resolution.

Emerging Roles of YAP/TAZ in Tooth and Surrounding: from Development to Regeneration.

Yes associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) are ubiquitous transcriptional co-activators that control organ development, homeostasis, and tissue regeneration. Current in vivo evidence suggests that YAP/TAZ regulates enamel knot formation during murine tooth development, and is indispensable for dental progenitor cell renewal to support constant incisor growth. Being a critical sensor for cellular mechano-transduction, YAP/TAZ lays at the center of the complex molecular network that integrates mechanical cues from the dental pulp chamber and surrounding periodontal tissue into biochemical signals, dictating in vitro cell proliferation, differentiation, stemness maintenance, and migration of dental stem cells. Moreover, YAP/TAZ-mediated cell-microenvironment interactions also display essential regulatory roles during biomaterial-guided dental tissue repair and engineering in some animal models. Here, we review recent advances in YAP/TAZ functions in tooth development, dental pulp, and periodontal physiology, as well as dental tissue regeneration. We also highlight several promising strategies that harness YAP/TAZ activation for promoting dental tissue regeneration.

Assessment of tumor microenvironment expression and clinical significance of immune inhibitory molecule CTLA-4, ligand B7-1, and tumor-infiltrating regulatory cells in Hodgkin lymphoma.

Classical Hodgkin lymphoma represents a paradigm of tumor cell-microenvironment interactions as the neoplastic Hodgkin Reed-Sternberg (HRS) cells typically constitute less than 1% of the total tumor volume. CTLA-4, a member of the CD28/B7 immunoglobulin superfamily, and CD28 and their ligands B7-1 and B7-2 are critically important for the initial activation of naive T cells. Strategies aimed at interfering with the crosstalk between tumoral Reed-Sternberg cells and their cellular partners have been taken into account in the development of new immunotherapies that target different cell components of the HL microenvironment. The study included 50 histopathological confirmed cases of Hodgkin lymphoma. IHC staining for CTLA-4 and B7-1 was performed on archival paraffin-embedded biopsy. SPSS version 17 was used for statistical analysis. CTLA-4 IHC expression in HRS cells was negative in all cases, while in immune cells, CTLA-4 expression was observed in 45 (90%) cases. CD80 expression was present in all cases, both in HRS and immune cells. There was a significant association between HRS cell percentage and IPS score (p-value=0.001). Mean survival duration was longer in <50% immune cells compared to >50% groups, with an overall mean survival of 67.633 months. Considering the CTLA4 expression in immune cells within the microenvironment and the availability of targeted drugs like Iplimumab, which act through CTLA4 blockade, it may be appropriate to use this as targeted therapy in HL cases, particularly in those with refractory disease who are unable to achieve cure prior to ASCT.

Application of spatial transcriptome technologies to neurological diseases.

Spatial transcriptome technology acquires gene expression profiles while retaining spatial location information, it displays the gene expression properties of cells in situ. Through the investigation of cell heterogeneity, microenvironment, function, and cellular interactions, spatial transcriptome technology can deeply explore the pathogenic mechanisms of cell-type-specific responses and spatial localization in neurological diseases. The present article overviews spatial transcriptome technologies based on microdissection, in situ hybridization, in situ sequencing, in situ capture, and live cell labeling. Each technology is described along with its methods, detection throughput, spatial resolution, benefits, and drawbacks. Furthermore, their applications in neurodegenerative disease, neuropsychiatric illness, stroke and epilepsy are outlined. This information can be used to understand disease mechanisms, pick therapeutic targets, and establish biomarkers.

Native extracellular matrix probes to target patient- and tissue-specific cell-microenvironment interactions by force spectroscopy.

Atomic Force Microscopy (AFM) is successfully used for the quantitative investigation of the cellular mechanosensing of the microenvironment. To this purpose, several force spectroscopy approaches aim at measuring the adhesive forces between two living cells and also between a cell and an appropriate reproduction of the extracellular matrix (ECM), typically exploiting tips suitably functionalised with single components (e.g. collagen, fibronectin) of the ECM. However, these probes only poorly reproduce the complexity of the native cellular microenvironment and consequently of the biological interactions. We developed a novel approach to produce AFM probes that faithfully retain the structural and biochemical complexity of the ECM; this was achieved by attaching to an AFM cantilever a micrometric slice of native decellularised ECM, which was cut by laser microdissection. We demonstrate that these probes preserve the morphological, mechanical, and chemical heterogeneity of the ECM. Native ECM probes can be used in force spectroscopy experiments aimed at targeting cell-microenvironment interactions. Here, we demonstrate the feasibility of dissecting mechanotransductive cell-ECM interactions in the 10 pN range. As proof-of-principle, we tested a rat bladder ECM probe against the AY-27 rat bladder cancer cell line. On the one hand, we obtained reproducible results using different probes derived from the same ECM regions; on the other hand, we detected differences in the adhesion patterns of distinct bladder ECM regions (submucosa, detrusor, and adventitia), in line with the disparities in composition and biophysical properties of these ECM regions. Our results demonstrate that native ECM probes, produced from patient-specific regions of organs and tissues, can be used to investigate cell-microenvironment interactions and early mechanotransductive processes by force spectroscopy. This opens new possibilities in the field of personalised medicine.

3D collagen microchamber arrays for combined chemotherapy effect evaluation on cancer cell numbers and migration.

Breast cancer metastasis involves complex mechanisms, particularly when patients are undergoing chemotherapy. In tissues, tumor cells encounter cell-cell interactions, cell-microenvironment interactions, complex nutrient, and drug gradients. Currently, two-dimensional cell culture systems and animal models are challenging to observe and analyze cell responses to microenvironments with various physical and bio-chemical conditions, and microfluidic technology has been systematically developed to address this dilemma. In this study, we have constructed a combined chemotherapy evaluation chip (CCEC) based on microfluidic technology. The chip possesses 192 diamond-shaped microchambers containing MDA-MB-231-RFP cells, and each microchamber is composed of collagen to mimic breast cancer and its surrounding microenvironment. In addition, by adding medium containing different drugs to the medium channels of CCEC, composite drug (paclitaxel+gemcitabine+7rh and paclitaxel+fluorouracil+PP2) concentration gradients, and single drug (paclitaxel, gemcitabine, 7rh, fluorouracil, PP2) concentration gradients have been established in the five collagen regions, respectively, so that each localized microchamber in the regions has a unique drug microenvironment. In this way, we evaluated the composite and single chemotherapy efficacy on the same chip by statistically analyzing their effects on the numbers and migration of the cell. The quantitative results in CCECs reveal that the inhibition effects on the numbers and migration of MDA-MB-231-RFP cell under the composite drug gradients are more optimal than those of the single drugs. Besides, the cancer cell inhibition effect between the groups composed of two drugs has also been compared, that is the paclitaxel+gemcitabine, paclitaxel+fluorouracil, and paclitaxel+PP2 have better cell numbers and migration inhibition effects than paclitaxel+7rh. The results indicate that the bio-mimetic and high-throughput combined chemotherapy evaluation platform can serve as a more efficient and accurate tool for preclinical drug development and screening.

EP16.04-019 Impact of Chemotherapy on Tridimensional Multicellular Non-small Cell Lung Cancer Spheroids with Microenvironment Cells

Platinum-based chemotherapy in combination with immunotherapy is a standard of care in advanced non-small cell lung cancer (NSCLC) patients. However, some of them will not benefit from this combination. A better understanding of cancer mechanisms and drug resistance is highly needed, and 3D culture models might help to understand cell-cell and tumor cell-microenvironment interactions. Our study aimed to develop a model of tridimensional multicellular tumor spheroids (MCTS) including non-squamous NSCLC cells with various baseline PD-L1 expression with or without tumor microenvironment, to analyze the impact of chemotherapy.

Conducting Polymer-ECM Scaffolds for Human Neuronal Cell Differentiation.

3D cell culture formats more closely resemble tissue architecture complexity than 2D systems, which are lacking most of the cell-cell and cell-microenvironment interactions of the in vivo milieu. Scaffold-based systems integrating natural biomaterials are extensively employed in tissue engineering to improve cell survival and outgrowth, by providing the chemical and physical cues of the natural extracellular matrix (ECM). Using the freeze-drying technique, porous 3D composite scaffolds consisting of poly(3,4-ethylene-dioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS), containing ECM components (i.e., collagen, hyaluronic acid, and laminin) are engineered for hosting neuronal cells. The resulting scaffolds exhibit a highly porous microstructure and good conductivity, determined by scanning electron microscopy and electrochemical impedance spectroscopy, respectively. These supports boast excellent mechanical stability and water uptake capacity, making them ideal candidates for cell infiltration. SH-SY5Y human neuroblastoma cells show enhanced cell survival and proliferation in the presence of ECM compared to PEDOT:PSS alone. Whole-cell patch-clamp recordings acquired from differentiated SHSY5Y cells in the scaffolds demonstrate that ECM constituents promote neuronal differentiation in situ. These findings reinforce the usability of 3D conducting supports as engineered highly biomimetic and functional in vitro tissue-like platforms for drug or disease modeling.

Surface-Sensitive Imaging Analysis of Cell-Microenvironment Interactions by Electrochemiluminescence Microscopy.

A complex and heterogeneous cell microenvironment offers not only structural support for cells but also myriad biochemical and biophysical cues. These outside-in signals transmit into cells primarily through integrins, which are the important components of cell-matrix adhesions to direct and maintain cell behaviors and fate. In this work, we report a surface-sensitive imaging methodology for evaluating the difference in cell-matrix adhesions at the single cell level to dissect the impact of the chemical microenvironment on cell behaviors. Cells were cultured on silica nanochannel membrane (SNM) modified indium tin oxide (ITO) electrodes (SNM/ITO) with different terminal surfaces and imaged by electrochemiluminescence microscopy (ECLM). The results show that the surface tethered with Arg-Gly-Asp (RGD) groups can mediate robust cell-microenvironment interaction and those coated with silanol and (3-aminopropyl)triethoxysilane (APTES) groups transmit an intermediate adhesion, while oligo(ethylene glycol) (OEG) coated surface conveys the weakest cell-matrix adhesion. Specific recognition of integrins to different surfaces was further explored in conjunction with selective immunoblocking of different subunits. α6, α5, and α1 integrin subunits were found to recognize SNM, RGD/OEG, and APTES surfaces, respectively. The work provides not only insights into cell-microenvironment interaction but also guideline in the design and development of functional and biomimetic surface materials.

A Graph Based Neural Network Approach to Immune Profiling of Multiplexed Tissue Samples.

Multiplexed immunofluorescence provides an un-precedented opportunity for studying specific cell-to-cell and cell microenvironment interactions. We employ graph neural networks to combine features obtained from tissue morphology with measurements of protein expression to profile the tumour microenvironment associated with different tumour stages. Our framework presents a new approach to analysing and processing these complex multi-dimensional datasets that overcomes some of the key challenges in analysing these data and opens up the opportunity to abstract biologically meaningful interactions.

Triboelectric Nanogenerators for Cellular Bioelectrical Stimulation

AbstractTriboelectric nanogenerators (TENGs) are an efficient state‐of‐the‐art kinetic energy‐harvesting technology based on the combination of triboelectrification and electrostatic induction to generate electrical energy from ambient mechanical energy. Bioelectricity is a quintessential characteristic of living organisms and has a crucial role in physiological and medical sciences. Living cells are capable of generating electrical signals and responding to electrical stimulation, which are known to be key properties that regulate cellular behaviors and cell–microenvironment interactions. TENGs, with the advantages of miniaturization and efficiency, are notably exploited in efforts to provide self‐powered electrical stimulation to cells for functional modulation or fate determination, leading to a new methodology in biology and medical science. In this review, the progress, challenges, and future prospects of cellular bioelectrical stimulation with TENGs are focused. The regulation of cellular activity involved in functional modulation and fate determination stimulated by TENGs is highlighted. Furthermore, the application of cell activity changes stimulated by TENGs is stressed in tissue regeneration, physiological function rehabilitation, and electroporation‐based drug delivery for disease therapy. Finally, the challenges and opportunities of using TENGs for electrical stimulation are presented for cell engineering in the biosciences and health care.

α4-Integrin deficiency in human CD34+ cells engenders precocious erythroid differentiation but inhibits enucleation

The functional impact of integrin expression in erythropoiesis has been previously emphasized through its decisive influence on erythroid cell-microenvironment (matrix and cellular) interactions, especially under conditions of stress. Beyond that, in several in vitro studies the relationship between the two erythroid integrins, α4 and α5, has been incongruous in terms of a proliferative support, either synergistic or antagonistic, whereas a dominant influence of α4 integrin on terminal erythropoiesis in vitro and in vivo has been consistently emphasized. However, the specific cellular and molecular details of this effect have not been defined, especially for human cells. In the study described here, we cultured human CD34+ progenitor cells with induced deficiency of α4 integrin (shRNAα4) under erythroid differentiation conditions, in which expanded erythroid progenitor cells are directed to terminal erythroid maturation stages in the absence of any microenvironmental influence. Our data indicate that early proliferative expansion in cells lacking α4 expression is significantly limited, but although erythroid cell differentiation can proceed normally to terminal stages, their enucleation is drastically impaired. This novel aspect of α4 integrin participation in the enucleation process in vitro resonates on the lack of in vivo enucleation of primitive erythroid cells lacking any integrin expression but affecting adult cells only under stress conditions.

Establishment of a human 3D pancreatic ductal adenocarcinoma model based on a patient-derived extracellular matrix scaffold

Background: There is a lack of models reflecting the tumour microenvironment (TME) at both structural and cellular level in pancreatic duct adenocarcinoma (PDAC). We propose an engineered model of PDAC that summarises the architectural and biochemical cues of PDAC and that could serve as a powerful tool for capturing cell-microenvironment interactions relevant to cancer progression and treatment.