This paper presents a review on state-of-the-art of thin-film transistor (TFT) technology and its wide range of applications, not only in liquid crystal displays (TFT-LCDs), but also in sensing devices. The history of the evolution of the technology is first given. Then the standard applications of TFT-LCDs, and X-ray detectors, followed by state-of-the-art applications in the field of chemical and biochemical sensing are presented. TFT technology allows the fabrication of dense arrays of independent and transparent microelectrodes on large glass substrates. The potential of these devices as electrical substrates for biological cell applications is then described. The possibility of using TFT array substrates as new tools for electrical experiments on biological cells has been investigated for the first time by our group. Dielectrophoresis experiments and impedance measurements on yeast cells are presented here. Their promising results open the door towards new applications of TFT technology.
Mutations within the human desmin gene are responsible for a subcategory of myofibrillar myopathies called desminopathies. However, a single inherited mutation can produce different phenotypes within a family, suggesting that environmental factors influence disease states. Although several mouse models have been used to investigate organ-specific desminopathies, a more general mechanistic perspective is required to advance our knowledge toward patient treatment. To improve our understanding of disease pathology, we have developed cellular models to observe desmin behaviour in early stages of disease pathology, e.g., upon formation of cytoplasmic desmin aggregates, within an isogenic background. We cloned the wildtype and three mutant desmin cDNAs using a Tet-On Advanced® expression system in C2C12 cells. Mutations were selected based on positioning within desmin and capacity to form aggregates in transient experiments, as follows: DesS46Y (head domain; low aggregation), DesD399Y (central rod domain; high aggregation), and DesS460I (tail domain; moderate aggregation). Introduction of these proteins into a C2C12 background permitted us to compare between desmin variants as well as to determine the role of external stress on aggregation. Three different types of stress, likely encountered during muscle activity, were introduced to the cell models—thermal (heat shock), redox-associated (H2O2 and cadmium chloride), and mechanical (stretching) stresses—after which aggregation was measured. Cells containing variant DesD399Y were more sensitive to stress, leading to marked cytoplasmic perinuclear aggregations. We then evaluated the capacity of biochemical compounds to prevent this aggregation, applying dexamethasone (an inducer of heat shock proteins), fisetin or N-acetyl-L-cysteine (antioxidants) before stress induction. Interestingly, N-acetyl-L-cysteine pre-treatment prevented DesD399Y aggregation during most stress. N-acetyl-L-cysteine has recently been described as a promising antioxidant in myopathies linked to selenoprotein N or ryanodin receptor defects. Our findings indicate that this drug warrants further study in animal models to speed its potential development as a therapy for DesD399Y-linked desminopathies.
Cardiovascular diseases are a leading cause of death worldwide. After an ischemic injury, the myocardium undergoes severe necrosis and apoptosis, leading to a dramatic degradation of function. Numerous studies have reported that cardiac fibroblasts (CFs) play a critical role in heart function even after injury. However, CFs present heterogeneous characteristics according to their development stage (i.e., fetal or adult), and the molecular mechanisms by which they maintain heart function are not fully understood. The aim of this study is to explore the hypothesis that a specific population of CFs can repair the injured myocardium in heart failure following ischemic infarction, and lead to a significant recovery of cardiac function. Flow cytometry analysis of CFs defined two subpopulations according to their relative expression of vascular cell adhesion molecule 1 (VCAM1). Whole-transcriptome analysis described distinct profiles for these groups, with a correlation between VCAM1 expression and lymphangiogenesis-related genes up-regulation. Vascular formation assays showed a significant stimulation of lymphatic cells network complexity by VCFs. Injection of human VCAM1-expressing CFs (VCFs) in postinfarct heart failure rat models (ligation of the left anterior descending artery) led to a significant restoration of the left ventricle contraction. Over the course of the experiment, left ventricular ejection fraction and fractional shortening increased by 16.65% ± 5.64% and 10.43% ± 6.02%, respectively, in VCF-treated rats. Histological examinations revealed that VCFs efficiently mobilized the lymphatic endothelial cells into the infarcted area. In conclusion, human CFs present heterogeneous expression of VCAM1 and lymphangiogenesis-promoting factors. VCFs restore the mechanical properties of ventricular walls by mobilizing lymphatic endothelial cells into the infarct when injected into a rat heart failure model. These results suggest a role of this specific population of CFs in the homeostasis of the lymphatic system in cardiac regeneration, providing new information for the study and therapy of cardiac diseases.
Highlights ►Desmin mutations trigger variable aggregative patterns and NAC pretreatment avoids it. ►Desmin mutations induce delayed oxidation kinetic with H2O2 stress, which are prevented by NAC. ►Stresses induce own post-aggregative post-translational modifications, which are prevented by NAC. ►Distinct pathological molecular mechanisms of desmin mutations weigh on therapeutics.
Human induced pluripotent stem cells have been investigated through a sequential in vitro step-by-step differentiation into hepatocyte-like cells using nanoCAGE, an original method for promoters, transcription factors, and transcriptome analysis.
This paper reports for the first time the use of TFT (Thin Film Transistor) technology of display panels for biological cells electrical manipulation. This technology allows to have high density distributed transparent micro-electrodes, independently controllable, covering centimeter-size glass substrates. This technology is much superior to usual micro-technology used for Multielectrode Arrays (MEAs), which allows only millimeter size surface with micro-electrodes, and with a limited number of 64 micro-electrodes maximum. The chosen application, to demonstrate the capability of such technology, is dielectrophoresis on micro-beads and yeast cells.
The induction or inhibition of angiogenesis can be assessed in vitro by the differentiation of endothelial cells. Indeed, these cells are capable of forming structures resembling a capillary network in culture. This approach is known as Endothelial Tube Formation Assay (ETFA). This type of analysis is traditionally performed on a low confluence monolayer of cells to assay the effect of soluble compounds on the formation of tubes. However, the modulation of tube formation by cell-cell interactions requires the co-culture of cells that leads to the creation of a multi-layer micro-tissue. Additionally, the identification of cells in the micro-tissue requires fluorescent staining resulting in discontinuities in the signal. EXTERNAL LINK 1 08/06/2020 C ita tio n : C ita tio n : Bertrand-David Segard (08/06/2020). Quantification of tube topography on micrographs of fluorescent staining of multi-layers cell culture..
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