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Overview of Immune Tolerance Strategies
Published in Richard K. Burt, Alberto M. Marmont, Stem Cell Therapy for Autoimmune Disease, 2019
Charles J. Hackett, Helen Quill
T cells expressing the cell surface molecules CD4 plus CD25 (CD4+CD25+ T cells) have recently been defined in humans and are known to play a major regulatory role in animal models of autoimmune diseases, including control of type I diabetes, central nervous system autoimmune inflammation, and intestinal autoreactivity.12 CD4+CD25+ T cells develop in the thymus like conventional T cells, and respond to as yet unknown self-antigens. When activated in vitro, they respond with a low level of cell division, but become potent suppressors of other T cells nearby. CD4+CD25+ T cells appear to act mainly by cell-to-cell contact rather than by secreted factors. Most likely, these regulatory cells respond to specific self-antigens presented by activated APC in affected tissues and act to suppress local inflammatory responses.
Worked-out Examples
Published in Marialuisa Aliotta, Mastering Academic Writing in the Sciences, 2018
3. Colorectal cancer is the second most common cause of cancer deaths in the developed world, accounting for 12% of all cancer deaths in Europe, and almost 700,000 total deaths in the world every year. The incidence of colorectal cancer is predicted to increase in the near future, as lifespans increase and more people adopt Western lifestyles and diets. 4. In the digestive tract, cells originate from stem cells in the crypt base and migrate upwards towards the gut lumen where they are shed within 3 to 5 days, ensuring continual removal of cells. When mutations occur that affect migration, this process is inhibited or slowed down, which can result in the development of cancer. In over 90% of colorectal cancers, mutations in the adenomatous polyposis coli (Apc) gene are present. The APC protein is linked to proliferation, differentiation and migration, consistent with changes in all these processes in cancer.
Nanotherapeutics: Enabling Vitamin D3 as a Multifaceted Nutraceutical
Published in Bhupinder Singh, Minna Hakkarainen, Kamalinder K. Singh, NanoNutraceuticals, 2019
Krantisagar S. More, Vinod S. Ipar, Amit S. Lokhande, Anisha A. D’souza, Padma V. Devarajan
In the cytoplasm, β-catenin is found in association with APC (adenomatous polyposis coli). Activation of Wnt signalling leads to β-catenin accumulation and its subsequent release from APC. This free β-catenin then interferes with DNA in the nucleus and activates transcription of genes, which regulates proliferation. Mutations in the APC gene lead to cancer progression. 1,25(OH)2D can block β-catenin-mediated gene transcription by inducing binding of VDR to β-catenin (Ben-Shoshan et al., 2007; Fleet et al., 2012).
Purification and characterization of Protein C activator from Agkistrodon acutus Venom
Published in Preparative Biochemistry & Biotechnology, 2020
Yao Sun, Peng-Ju Bao, Gen-Bao Zhang
Protein C (PC) is a vitamin K-dependent protein that circulates in the blood.[1] The protein C zymogen is activated upon binding to thrombin,[2] and its activation is induced by the presence of thrombomodulin (TM) and endothelial protein C receptors (EPCR).[3] PC is hydrolyzed from a peptide chain to become activated protein C (APC). APC plays important roles in the regulation of blood clotting,[4] inflammation,[5] cell death, and blood vessel wall permeability in humans and other animals[6] by proteolytically inactivating factors Va and VIIIa. Because of the crucial role of protein C as an anticoagulant, individuals with deficiencies in protein C or resistance to APC[7] are at increased risk of developing life-threatening blood clots. A decrease in the PC level generally associates with a decrease in PC activity. However, in some cases, the level of PC is normal but the activity of PC has been reduced by half.[8] Therefore, the detection of PC activity is more diagnostically significant for patients with cardiovascular diseases. Presently, the key methods to detect PC activity[9] are the chromogenic assay and APTT test.[10] In a previous study, it was reported that snake venom contains an enzyme that activates plasma PC independent of thrombomodulin–endothelial protein C receptor (TM/EPCR).[11] This protein has been designated as protein C activator (PCA). Other studies have demonstrated that PCA is mainly present in Agkistrodon halys halys snake venom.[12] PCA has a molecular mass of approximately 37 kD[13] and is a valuable commodity named PROTAC,[14] which is isolated from Agkistrodon contortrix contortrix venom (ACCV). However, the use of the chromogenic assay is limited because of the high price of PROTAC.