scholarly journals Synthetic Biology: Engineering Mammalian Cells To Control Cell‐to‐Cell Communication at Will

ChemBioChem ◽  
2019 ◽  
Vol 20 (8) ◽  
pp. 994-1002 ◽  
Author(s):  
Ryosuke Kojima ◽  
Martin Fussenegger
Keyword(s):  
Synthetic Biology ◽  
Mammalian Cells ◽  
Control Cell ◽  
Cell Communication ◽  
At Will

scholarly journals GCN2 phosphorylation of eIF2α activates NF-κB in response to UV irradiation

2005 ◽  
Vol 385 (2) ◽  
pp. 371-380 ◽  
Author(s):  
Hao-Yuan JIANG ◽  
Ronald C. WEK
Keyword(s):  
Uv Irradiation ◽  
Mammalian Cells ◽  
Transcriptional Control ◽  
Control Cell ◽  
Nuclear Factor Κb ◽  
Initiation Factor ◽  
Α Subunit ◽  
Eif2α Phosphorylation ◽  
Eif2α Kinase ◽  
Secondary Function

In response to UV irradiation, mammalian cells elicit a gene expression programme designed to repair damage and control cell proliferation and apoptosis. Important members of this stress response include the NF-κB (nuclear factor-κB) family. However, the mechanisms by which UV irradiation activates NF-κB are not well understood. In eukaryotes, a variety of environmental stresses are recognized and remediated by a family of protein kinases that phosphorylate the α subunit of eIF2 (eukaryotic initiation factor-2). In the present study we show that NF-κB in MEF (murine embryo fibroblast) cells is activated by UV-C and UV-B irradiation through a mechanism requiring eIF2α phosphorylation. The primary eIF2α kinase in response to UV is GCN2 (general control non-derepressible-2), with PEK/PERK (pancreatic eIF2α kinase/RNA-dependent-protein-kinase-like endoplasmic-reticulum kinase) carrying out a secondary function. Our studies indicate that lowered protein synthesis accompanying eIF2α phosphorylation, combined with eIF2α kinase-independent turnover of IκBα (inhibitor of κBα), reduces the levels of IκBα in response to UV irradiation. Release of NF-κB from the inhibitory IκBα would facilitate NF-κB entry into the nucleus and targeted transcriptional control. We also find that loss of GCN2 in MEF cells significantly enhances apoptosis in response to UV exposure similar to that measured in cells deleted for the RelA/p65 subunit of NF-κB. These results demonstrate that GCN2 is central to recognition of UV stress, and that eIF2α phosphorylation provides resistance to apoptosis in response to this environmental insult.

Calcium and cell cycle control

Development ◽  
1990 ◽  
Vol 108 (4) ◽  
pp. 525-542 ◽  
Author(s):  
M. Whitaker ◽  
R. Patel
Keyword(s):  
Cell Cycle ◽  
Sea Urchin ◽  
Mammalian Cells ◽  
Cell Cycle Regulation ◽  
Sea Urchins ◽  
Cell Cycle Control ◽  
Control Point ◽  
Control Cell ◽  
Free Calcium ◽  
Cycle Regulation

The cell division cycle of the early sea urchin embryo is basic. Nonetheless, it has control points in common with the yeast and mammalian cell cycles, at START, mitosis ENTRY and mitosis EXIT. Progression through each control point in sea urchins is triggered by transient increases in intracellular free calcium. The Cai transients control cell cycle progression by translational and post-translational regulation of the cell cycle control proteins pp34 and cyclin. The START Cai transient leads to phosphorylation of pp34 and cyclin synthesis. The mitosis ENTRY Cai transient triggers cyclin phosphorylation. The motosis EXIT transient causes destruction of phosphorylated cyclin. We compare cell cycle regulation by calcium in sea urchin embryos to cell cycle regulation in other eggs and oocytes and in mammalian cells.

scholarly journals Histone demethylase KDM6A directly senses oxygen to control chromatin and cell fate

Science ◽  
2019 ◽  
Vol 363 (6432) ◽  
pp. 1217-1222 ◽  
Author(s):  
Abhishek A. Chakraborty ◽  
Tuomas Laukka ◽  
Matti Myllykoski ◽  
Alison E. Ringel ◽  
Matthew A. Booker ◽  
...  
Keyword(s):  
Cell Fate ◽  
Histone Methylation ◽  
Mammalian Cells ◽  
Control Cell ◽  
Hypoxia Inducible Factor ◽  
Histone Demethylase ◽  
Histone Demethylases ◽  
Independent Manner ◽  
H3k27 Methylation ◽  
Oxygen Sensitive

Oxygen sensing is central to metazoan biology and has implications for human disease. Mammalian cells express multiple oxygen-dependent enzymes called 2-oxoglutarate (OG)-dependent dioxygenases (2-OGDDs), but they vary in their oxygen affinities and hence their ability to sense oxygen. The 2-OGDD histone demethylases control histone methylation. Hypoxia increases histone methylation, but whether this reflects direct effects on histone demethylases or indirect effects caused by the hypoxic induction of the HIF (hypoxia-inducible factor) transcription factor or the 2-OG antagonist 2-hydroxyglutarate (2-HG) is unclear. Here, we report that hypoxia promotes histone methylation in a HIF- and 2-HG–independent manner. We found that the H3K27 histone demethylase KDM6A/UTX, but not its paralog KDM6B, is oxygen sensitive. KDM6A loss, like hypoxia, prevented H3K27 demethylation and blocked cellular differentiation. Restoring H3K27 methylation homeostasis in hypoxic cells reversed these effects. Thus, oxygen directly affects chromatin regulators to control cell fate.

scholarly journals Role and mechanisms of exosomal miRNAs in IBD pathophysiology

2020 ◽  
Vol 319 (6) ◽  
pp. G646-G654
Author(s):  
Sameena Wani ◽  
Ivy Ka Man Law ◽  
Charalabos Pothoulakis
Keyword(s):  
Information Exchange ◽  
Mammalian Cells ◽  
Target Genes ◽  
Cell Function ◽  
Recipient Cell ◽  
Intestinal Flora ◽  
Cell Communication ◽  
Gut Health ◽  
Specific Loading ◽  
Exosomal Mirnas

Exosomes represent secretory membranous vesicles used for the information exchange between cells and organ-to-organ communication. Exosome crosstalk mechanisms are involved in the regulation of several inflammatory bowel disease (IBD)-associated pathophysiological intestinal processes such as barrier function, immune responses, and intestinal flora. Functional biomolecules, mainly noncoding RNAs (ncRNAs), are believed to be transmitted between the mammalian cells via exosomes that likely play important roles in cell-to-cell communication, both locally and systemically. MicroRNAs (miRNAs) encapsulated in exosomes have generated substantial interest because of their critical roles in multiple pathophysiological processes. In addition, exosomal miRNAs are implicated in the gut health. MiRNAs are selectively and actively loaded into the exosomes and then transferred to the target recipient cell where they manipulate cell function through posttranscriptional silencing of target genes. Intriguingly, miRNA profile of exosomes differs from their cellular counterparts suggesting an active sorting and packaging mechanism of exosomal miRNAs. Even more exciting is the involvement of posttranscriptional modifications in the specific loading of miRNAs into exosomes, but the underlying mechanisms of how these modifications direct ncRNA sorting have not been established. This review gives a brief overview of the status of exosomes and exosomal miRNAs in IBD and also discusses potential mechanisms of exosomal miRNA sorting and delivering.

scholarly journals An Integrative Synthetic Biology Approach to Interrogating Cellular Ubiquitin and Ufm Signaling

2020 ◽  
Vol 21 (12) ◽  
pp. 4231 ◽  
Author(s):  
Chuanyin Li ◽  
Tianting Han ◽  
Rong Guo ◽  
Peng Chen ◽  
Chao Peng ◽  
...  
Keyword(s):  
Synthetic Biology ◽  
Mammalian Cells ◽  
Open Reading Frames ◽  
Post Translational Modifications ◽  
E3 Ligases ◽  
Cloning Technique ◽  
Global Identification ◽  
Multiple Hit ◽  
Reading Frames ◽  
Synthetic Biology Approach

Global identification of substrates for PTMs (post-translational modifications) represents a critical but yet dauntingly challenging task in understanding biology and disease pathology. Here we presented a synthetic biology approach, namely ‘YESS’, which coupled Y2H (yeast two hybrid) interactome screening with PTMs reactions reconstituted in bacteria for substrates identification and validation, followed by the functional validation in mammalian cells. Specifically, the sequence-independent Gateway® cloning technique was adopted to afford simultaneous transfer of multiple hit ORFs (open reading frames) between the YESS sub-systems. In proof-of-evidence applications of YESS, novel substrates were identified for UBE3A and UFL1, the E3 ligases for ubiquitination and ufmylation, respectively. Therefore, the YESS approach could serve as a potentially powerful tool to study cellular signaling mediated by different PTMs.

scholarly journals Synthetic Virus-Derived Nanosystems (SVNs) for Delivery and Precision Docking of Large Multifunctional DNA Circuitry in Mammalian Cells

Pharmaceutics ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 759
Author(s):  
Francesco Aulicino ◽  
Julien Capin ◽  
Imre Berger
Keyword(s):  
Gene Therapy ◽  
Synthetic Biology ◽  
Base Pair ◽  
Mammalian Cells ◽  
Viral Vectors ◽  
Genome Engineering ◽  
Dna Delivery ◽  
Attractive Alternative ◽  
Exogenous Dna ◽  
Nonviral Delivery

DNA delivery is at the forefront of current research efforts in gene therapy and synthetic biology. Viral vectors have traditionally dominated the field; however, nonviral delivery systems are increasingly gaining traction. Baculoviruses are arthropod-specific viruses that can be easily engineered and repurposed to accommodate and deliver large sequences of exogenous DNA into mammalian cells, tissues, or ultimately organisms. These synthetic virus-derived nanosystems (SVNs) are safe, readily customized, and can be manufactured at scale. By implementing clustered regularly interspaced palindromic repeats (CRISPR) associated protein (CRISPR/Cas) modalities into this system, we developed SVNs capable of inserting complex DNAs into genomes, at base pair precision. We anticipate a major role for SVNs as an attractive alternative to viral vectors in accelerating genome engineering and gene therapy applications in the future.

scholarly journals Extracellular Vesicles as Inflammatory Drivers in NAFLD

2021 ◽  
Vol 11 ◽  
Author(s):  
Akshatha N. Srinivas ◽  
Diwakar Suresh ◽  
Prasanna K. Santhekadur ◽  
Deepak Suvarna ◽  
Divya P. Kumar
Keyword(s):  
Liver Disease ◽  
Fatty Liver ◽  
Extracellular Vesicles ◽  
Mammalian Cells ◽  
Cell Communication ◽  
Alcoholic Fatty Liver ◽  
Whole Process ◽  
Obesity And Diabetes ◽  
Immune Mediated ◽  
End Stage

Non-alcoholic fatty liver disease (NAFLD) is a highly prevalent chronic liver disease in most parts of the world affecting one-third of the western population and a growing cause for end-stage liver diseases such as hepatocellular carcinoma (HCC). Majorly driven by obesity and diabetes mellitus, NAFLD is more of a multifactorial disease affected by extra-hepatic organ crosstalk. Non-alcoholic fatty liver (NAFL) progressed to non-alcoholic steatohepatitis (NASH) predisposes multiple complications such as fibrosis, cirrhosis, and HCC. Although the complete pathogenic mechanisms of this disease are not understood, inflammation is considered as a key driver to the onset of NASH. Lipotoxicity, inflammatory cytokines, chemokines, and intestinal dysbiosis trigger both hepatic and systemic inflammatory cascades simultaneously activating immune responses. Over a few years, extracellular vesicles studied extensively concerning the pathobiology of NAFLD indicated it as a key modulator in the setting of immune-mediated inflammation. Exosomes and microvesicles, the two main types of extracellular vesicles are secreted by an array of most mammalian cells, which are involved mainly in cell-cell communication that are unique to cell type. Various bioactive cargoes containing extracellular vesicles derived from both hepatic and extrahepatic milieu showed critical implications in driving steatosis to NASH reaffirming inflammation as the primary contributor to the whole process. In this mini-review, we provide brief insights into the inflammatory mediators of NASH with special emphasis on extracellular vesicles that acts as drivers of inflammation in NAFLD.

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