scholarly journals HDAC4 Promotes Growth of Colon Cancer Cells via Repression of p21

2008 ◽  
Vol 19 (10) ◽  
pp. 4062-4075 ◽  
Author(s):  
Andrew J. Wilson ◽  
Do-Sun Byun ◽  
Shannon Nasser ◽  
Lucas B. Murray ◽  
Kanyalakshmi Ayyanar ◽  
...  
Keyword(s):  
Growth Promotion ◽  
Cell Types ◽  
Specific Cell ◽  
Physical Interaction ◽  
Down Regulation ◽  
Proliferative Zone ◽  
P21 Promoter ◽  
Hct116 Cells

The class II Histone deacetylase (HDAC), HDAC4, is expressed in a tissue-specific manner, and it represses differentiation of specific cell types. We demonstrate here that HDAC4 is expressed in the proliferative zone in small intestine and colon and that its expression is down-regulated during intestinal differentiation in vivo and in vitro. Subcellular localization studies demonstrated HDAC4 expression was predominantly nuclear in proliferating HCT116 cells and relocalized to the cytoplasm after cell cycle arrest. Down-regulating HDAC4 expression by small interfering RNA (siRNA) in HCT116 cells induced growth inhibition and apoptosis in vitro, reduced xenograft tumor growth, and increased p21 transcription. Conversely, overexpression of HDAC4 repressed p21 promoter activity. p21 was likely a direct target of HDAC4, because HDAC4 down-regulation increased p21 mRNA when protein synthesis was inhibited by cycloheximide. The importance of p21 repression in HDAC4-mediated growth promotion was demonstrated by the failure of HDAC4 down-regulation to induce growth arrest in HCT116 p21-null cells. HDAC4 down-regulation failed to induce p21 when Sp1 was functionally inhibited by mithramycin or siRNA-mediated down-regulation. HDAC4 expression overlapped with that of Sp1, and a physical interaction was demonstrated by coimmunoprecipitation. Chromatin immunoprecipitation (ChIP) and sequential ChIP analyses demonstrated Sp1-dependent binding of HDAC4 to the proximal p21 promoter, likely directed through the HDAC4–HDAC3–N-CoR/SMRT corepressor complex. Consistent with increased transcription, HDAC4 or SMRT down-regulation resulted in increased histone H3 acetylation at the proximal p21 promoter locus. These studies identify HDAC4 as a novel regulator of colon cell proliferation through repression of p21.

Epithelial Organotypic Cultures: A Viable Model to Address Mechanisms of Carcinogenesis by Epitheliotropic Viruses

2018 ◽  
Vol 18 (4) ◽  
pp. 246-255 ◽  
Author(s):  
Lara Termini ◽  
Enrique Boccardo
Keyword(s):  
Three Dimensional ◽  
Cell Types ◽  
Experimental Models ◽  
Biological Research ◽  
Specific Gene ◽  
Specific Cell ◽  
Organotypic Cultures ◽  
Skin Physiology

In vitro culture of primary or established cell lines is one of the leading techniques in many areas of basic biological research. The use of pure or highly enriched cultures of specific cell types obtained from different tissues and genetics backgrounds has greatly contributed to our current understanding of normal and pathological cellular processes. Cells in culture are easily propagated generating an almost endless source of material for experimentation. Besides, they can be manipulated to achieve gene silencing, gene overexpression and genome editing turning possible the dissection of specific gene functions and signaling pathways. However, monolayer and suspension cultures of cells do not reproduce the cell type diversity, cell-cell contacts, cell-matrix interactions and differentiation pathways typical of the three-dimensional environment of tissues and organs from where they were originated. Therefore, different experimental animal models have been developed and applied to address these and other complex issues in vivo. However, these systems are costly and time consuming. Most importantly the use of animals in scientific research poses moral and ethical concerns facing a steadily increasing opposition from different sectors of the society. Therefore, there is an urgent need for the development of alternative in vitro experimental models that accurately reproduce the events observed in vivo to reduce the use of animals. Organotypic cultures combine the flexibility of traditional culture systems with the possibility of culturing different cell types in a 3D environment that reproduces both the structure and the physiology of the parental organ. Here we present a summarized description of the use of epithelial organotypic for the study of skin physiology, human papillomavirus biology and associated tumorigenesis.

scholarly journals Rho GTPases as Key Molecular Players within Intestinal Mucosa and GI Diseases

Cells ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 66
Author(s):  
Rashmita Pradhan ◽  
Phuong A. Ngo ◽  
Luz d. C. Martínez-Sánchez ◽  
Markus F. Neurath ◽  
Rocío López-Posadas
Keyword(s):  
Intestinal Mucosa ◽  
Rho Gtpases ◽  
Current Knowledge ◽  
Cell Types ◽  
Effector Proteins ◽  
Special Focus ◽  
Specific Cell ◽  
Rho Proteins

Rho proteins operate as key regulators of the cytoskeleton, cell morphology and trafficking. Acting as molecular switches, the function of Rho GTPases is determined by guanosine triphosphate (GTP)/guanosine diphosphate (GDP) exchange and their lipidation via prenylation, allowing their binding to cellular membranes and the interaction with downstream effector proteins in close proximity to the membrane. A plethora of in vitro studies demonstrate the indispensable function of Rho proteins for cytoskeleton dynamics within different cell types. However, only in the last decades we have got access to genetically modified mouse models to decipher the intricate regulation between members of the Rho family within specific cell types in the complex in vivo situation. Translationally, alterations of the expression and/or function of Rho GTPases have been associated with several pathological conditions, such as inflammation and cancer. In the context of the GI tract, the continuous crosstalk between the host and the intestinal microbiota requires a tight regulation of the complex interaction between cellular components within the intestinal tissue. Recent studies demonstrate that Rho GTPases play important roles for the maintenance of tissue homeostasis in the gut. We will summarize the current knowledge on Rho protein function within individual cell types in the intestinal mucosa in vivo, with special focus on intestinal epithelial cells and T cells.

Vertebrate retinal ganglion cells are selected from competent progenitors by the action of Notch

Development ◽  
1995 ◽  
Vol 121 (11) ◽  
pp. 3637-3650 ◽  
Author(s):  
C.P. Austin ◽  
D.E. Feldman ◽  
J.A. Ida ◽  
C.L. Cepko
Keyword(s):  
Cell Fate ◽  
Ganglion Cells ◽  
Notch Pathway ◽  
Cell Types ◽  
Projection Neurons ◽  
Specific Cell ◽  
Vitro Assay ◽  
Notch Activity

The first cells generated during development of the vertebrate retina are the ganglion cells, the projection neurons of the retina. Although they are one of the most intensively studied cell types within the central nervous system, little is known of the mechanisms that determine ganglion cell fate. We demonstrate that ganglion cells are selected from a large group of competent progenitors that comprise the majority of the early embryonic retina and that differentiation within this group is regulated by Notch. Notch activity in vivo was diminished using antisense oligonucleotides or augmented using a retrovirally transduced constitutively active allele of Notch. The number of ganglion cells produced was inversely related to the level of Notch activity. In addition, the Notch ligand Delta inhibited retinal progenitors from differentiating as ganglion cells to the same degree as did activated Notch in an in vitro assay. These results suggest a conserved strategy for neurogenesis in the retina and describe a versatile in vitro and in vivo system with which to examine the action of the Notch pathway in a specific cell fate decision in a vertebrate.

scholarly journals Human Organoids for Predictive Toxicology Research and Drug Development

2021 ◽  
Vol 12 ◽  
Author(s):  
Toshikatsu Matsui ◽  
Tadahiro Shinozawa
Keyword(s):  
Stem Cells ◽  
Drug Development ◽  
Disease Modeling ◽  
Cell Types ◽  
Underlying Disease ◽  
Future Research ◽  
Specific Cell ◽  
Predictive Toxicology

Organoids are three-dimensional structures fabricated in vitro from pluripotent stem cells or adult tissue stem cells via a process of self-organization that results in the formation of organ-specific cell types. Human organoids are expected to mimic complex microenvironments and many of the in vivo physiological functions of relevant tissues, thus filling the translational gap between animals and humans and increasing our understanding of the mechanisms underlying disease and developmental processes. In the last decade, organoid research has attracted increasing attention in areas such as disease modeling, drug development, regenerative medicine, toxicology research, and personalized medicine. In particular, in the field of toxicology, where there are various traditional models, human organoids are expected to blaze a new path in future research by overcoming the current limitations, such as those related to differences in drug responses among species. Here, we discuss the potential usefulness, limitations, and future prospects of human liver, heart, kidney, gut, and brain organoids from the viewpoints of predictive toxicology research and drug development, providing cutting edge information on their fabrication methods and functional characteristics.

Cell-specific and targeted delivery of RNA moieties

2020 ◽  
Author(s):  
Aditi Bhargava ◽  
Peter Ohara ◽  
Luc Jasmin
Keyword(s):  
Nucleic Acids ◽  
Targeted Delivery ◽  
Immune Cell ◽  
Neuronal Cell ◽  
Cell Types ◽  
Specific Cell ◽  
Chemically Modified ◽  
Covalently Linked

AbstractDelivery of therapeutic moieties to specific cell types, such as neurons remains a challenge. Genes present in neurons are also expressed in non-neuronal cell types such as glia where they mediate non-targeted related functions. Thus, non-specific targeting of these proteins/channels has numerous unwanted side effects, as is the case with current small molecules or drug therapies. Current methodologies that use nanoparticles, lipid-mediated uptake, or mannitol in conjunction with lipids to deliver double-stranded RNA (dsRNA) have yielded mixed and unreliable results. We used a neuroanatomical tracer (B subunit of Cholera Toxin (CTB)) that binds to the ganglioside receptors (GM1) expressed on cells, including primary sensory neurons to deliver encapsulated dsRNA. This approach greatly improved delivery of dsRNA to the desired cells by enhancing uptake, reducing vehicle-mediated toxicity and protecting nucleotides from degradation by endonucleases. The delivery complex is internalized, and once inside the cell, the dsRNA naturally dissociates itself from the carrier complex and is very effective in knocking down cognate targets, both in vivo and in vitro. Past methods have used CTB-fusion proteins or chemically modified oligos or DNA moieties that have been covalently conjugated to CTB. Furthermore, CTB conjugated to an antigen, protein, or chemically modified nucleic acid is a potent activator of immune cell (T and B cells, macrophages) response, whereas CTB admixed with antigens or unmodified nucleic acids does not evoke this immune response. Importantly, in our method, the nucleic acids are not covalently linked to the carrier molecules. Thus, our method holds strong potential for targeted delivery of therapeutic moieties for cell types expressing GM1 receptors, including neuronal cell types.

scholarly journals In vivo paracrine interaction between urokinase and its receptor: effect on tumor cell invasion.

1991 ◽  
Vol 115 (4) ◽  
pp. 1107-1112 ◽  
Author(s):  
L Ossowski ◽  
G Clunie ◽  
M T Masucci ◽  
F Blasi
Keyword(s):  
Chorioallantoic Membrane ◽  
Fold Increase ◽  
Cell Types ◽  
Cell Surface Receptor ◽  
In Vivo Model ◽  
Specific Cell ◽  
Upa Receptor ◽  
Surface Receptor

Numerous studies have linked the production of increased levels of urokinase type plasminogen activator (uPA) with the malignant phenotype. It has also been shown that a specific cell surface receptor can bind uPA through a domain distinct and distant from the proteolytic domain. In an in vivo model of invasion, consisting of experimentally modified chorioallantoic membrane (CAM) of a chick embryo, only cells that concurrently expressed both uPA and a receptor for uPA, and in which the receptor was saturated with uPA, were efficient in invasion. To test whether uPA produced by one cell can, in a paracrine fashion, affect the invasive capacity of a receptor-expressing cell, we transfected LB6 mouse cells with human uPA (LB6[uPA]), or human uPA-receptor cDNA (LB6[uPAR]). LB6(uPA) cells released into the medium 1-2 Ploug units of human uPA per 10(6) cells in 24 h. The LB6(uPAR) cells expressed on their surface approximately 12,000 high affinity (Kd 1.7 x 10(-10) M uPA binding sites per cell. Unlabeled LB6(uPA) and 125-IUdR-labeled LB6(uPAR) cells were coinoculated onto experimentally wounded and resealed CAMs and their invasion was compared to that of homologous mixtures of labeled and unlabeled LB6(uPAR) or LB6(uPA) cells. Concurrent presence of both cell types in the CAMs resulted in a 1.8-fold increase of invasion of the uPA-receptor expressing cells. A four-fold stimulation of invasion was observed when cells were cocultured in vitro, prior to in vivo inoculation. Enhancement of invasion was prevented in both sets of experiments by treatment with specific antihuman uPA antibodies, indicating that uPA was the main mediator of the invasion-enhancing, paracrine effect on the receptor-expressing cells.

scholarly journals An alternative approach to produce versatile retinal organoids with accelerated ganglion cell development

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Philip E. Wagstaff ◽  
Anneloor L. M. A. ten Asbroek ◽  
Jacoline B. ten Brink ◽  
Nomdo M. Jansonius ◽  
Arthur A. B. Bergen
Keyword(s):  
Ganglion Cells ◽  
Cell Types ◽  
Retinal Cell ◽  
Specific Cell ◽  
Retinal Ganglion ◽  
In Vivo Models ◽  
Alternative Approach

AbstractGenetically complex ocular neuropathies, such as glaucoma, are a major cause of visual impairment worldwide. There is a growing need to generate suitable human representative in vitro and in vivo models, as there is no effective treatment available once damage has occured. Retinal organoids are increasingly being used for experimental gene therapy, stem cell replacement therapy and small molecule therapy. There are multiple protocols for the development of retinal organoids available, however, one potential drawback of the current methods is that the organoids can take between 6 weeks and 12 months on average to develop and mature, depending on the specific cell type wanted. Here, we describe and characterise a protocol focused on the generation of retinal ganglion cells within an accelerated four week timeframe without any external small molecules or growth factors. Subsequent long term cultures yield fully differentiated organoids displaying all major retinal cell types. RPE, Horizontal, Amacrine and Photoreceptors cells were generated using external factors to maintain lamination.

scholarly journals Targeting neuronal and glial cell types with synthetic promoter AAVs in mice, non-human primates, and humans

2018 ◽  
Author(s):  
Josephine Jüttner ◽  
Arnold Szabo ◽  
Brigitte Gross-Scherf ◽  
Rei K. Morikawa ◽  
Santiago B. Rompani ◽  
...  
Keyword(s):  
Glial Cell ◽  
Viral Vectors ◽  
Cell Types ◽  
Mouse Retina ◽  
Specific Cell ◽  
Synthetic Promoter ◽  
Brain Circuits ◽  
Human Primate

SummaryTargeting genes to specific neuronal or glial cell types is valuable both for understanding and for repairing brain circuits. Adeno-associated viral vectors (AAVs) are frequently used for gene delivery, but targeting expression to specific cell types is a challenge. We created a library of 230 AAVs, each with a different synthetic promoter designed using four independent strategies. We show that ~11% of these AAVs specifically target expression to neuronal and glial cell types in the mouse retina, mouse brain, non-human primate retinain vivo, and in the human retinain vitro. We demonstrate applications for recording, stimulation, and molecular characterization, as well as the intersectional and combinatorial labeling of cell types. These resources and approaches allow economic, fast, and efficient cell-type targeting in a variety of species, both for fundamental science and for gene therapy.

Expression of Cardiac Specific Cell Marker in Ex Vivo Differentiated Canine iPSC

2019 ◽  
Author(s):  
Purnima Singh ◽  
Tanmay Mondal ◽  
Kuldeep Kumar ◽  
Kinsuk Das ◽  
N Mahalakshmi ◽  
...  
Keyword(s):  
Cardiac Tissue ◽  
Ex Vivo ◽  
Cell Types ◽  
Embryoid Bodies ◽  
Specific Gene ◽  
Specific Cell ◽  
Specific Marker ◽  
Cell Based Therapy

Induced Pluripotent stem cells (iPSC) have a high ability to renew and differentiate themselves into various lineages and as vehicles of cell based therapy. Stem cell can differentiate under appropriate in vitro and in vivo conditions into different cell types. This study described the establishment of condition for in vitro expression of alpha MHC gene in cardiac differentiated canine iPSC (ciPSC). In vitro differentiation of canine iPSCs via embryoid bodies (EBs) were produced by ‘Hanging Drop’ method. EB’s were differentiated by using IMDM differentiation media: FBS – 10%, NEAA (100X) – 0.5%, Â-Mercaptoethanol- 100mM, Gentamycin- 5µg/ml supplemented with Azacytidine- 0.5µM. During differentiation, EBs were collected on day 4, 6, 8, 12, 16, 20 and 24 for characterization of cardiomyocytes specific marker expression. Total RNA from EBs were extracted by using Trizol method and subsequently cDNA were synthesized. The differentiated cells expressed cardiac specific gene (Alpha MHC) which started from day 6 of differentiation upto day 24 Immunocytochemistry and relative expression of cardiac specific genes revealed that ciPSC have the potential to differentiate into cardiomyocytes which can be used for cardiac tissue regeneration and as disease models for pharmaceutical testing.

Polymeric Vectors for Strategic Delivery of Nucleic Acids

Nano LIFE ◽  
2017 ◽  
Vol 07 (02) ◽  
pp. 1730003
Author(s):  
Andrew Dunn ◽  
Donglu Shi
Keyword(s):  
Molecular Weight ◽  
Transfection Efficiency ◽  
Cell Types ◽  
Primary Amines ◽  
Biological Research ◽  
Specific Cell ◽  
Nucleic Acid Delivery ◽  
Biological Studies

Genomic modification through nucleic acid delivery is a frequently applied method in fundamental biological studies and offers a potent therapeutic strategy for disease treatment and biological research. Delivery of nucleic sequences is therefore an attractive facet of biological nanotechnology as highly specific, efficient, and nonantagonistic delivery is necessary for in vivo and clinical use. Previous vectors have suffered from immunogenic responses, serum dependent inactivation, and cytotoxicity, hindering their translational applicability. Current research in polymeric-based nucleotide delivery strives to offer a highly biocompatible, broad use vector through the utilization of polypeptide and polyamine conjugation that can be easily tailored for specific targeting or wide dissemination. Cross-linking low molecular weight polyamines and lipophilic derivatization for amphiphile creation has lead to improved biocompatibility and transfection efficiency compared to higher molecular weight polyamines. Derivatization of hyperbranched and dendritic polyamido- and polyamines has allowed for the formation of efficient in vivo transfection vectors; ring opening synthesis of N-carboxyanhydride amino acids have led to controlled peptide architectures for improved transfection while simultaneously providing convenient primary amines useful in functionalization. Polymer libraries of poly(ß-amino esters) have provided insights into useful architectures for in vitro and in vivo gene delivery. Grafting small molecules to polyamines, such as folate and galactose, for enhanced interaction with cell surface receptors for selective targeting of specific cell types has proven to be encouraging and remains a prominent aspect in biological nanotechnology.

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