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Sphingosine-1-phosphate
Sphingosine-1-phosphate (S1P) is a signaling sphingolipid, also known as lysosphingolipid. It is also referred to as a bioactive lipid mediator. Sphingolipids at large form a class of lipids characterized by a particular aliphatic aminoalcohol, which is sphingosine. Production S1P is formed from ceramide, which is composed of a sphingosine and a fatty acid. Ceramidase, an enzyme primarily present in plasma membrane, will convert ceramide to sphingosine. Sphingosine is then phosphorylated by sphingosine kinase (SK) isoenzymes. There are two identified mammalian isoenzymes, SK1 and SK2. These two enzymes have different tissue distribution. SK1 is highly expressed in spleen, lung and leukocytes, while SK2 is highly expressed in liver and kidney. SK2 is located mainly in the mitochondria, nucleus and the endoplasmic reticulum whereas SK1 is mainly located in cytoplasm and the cell membrane. Metabolism and degradation S1P can be dephosphorylated to sphingosine by sphingosin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
S1PR1
Sphingosine-1-phosphate receptor 1 (S1P receptor 1 or S1PR1), also known as endothelial differentiation gene 1 (EDG1) is a protein that in humans is encoded by the ''S1PR1'' gene. S1PR1 is a G-protein-coupled receptor which binds the bioactive signaling molecule sphingosine 1-phosphate (S1P). S1PR1 belongs to a sphingosine-1-phosphate receptor subfamily comprising five members (S1PR1-5). S1PR1 was originally identified as an abundant transcript in endothelial cells and it has an important role in regulating endothelial cell cytoskeletal structure, migration, capillary-like network formation and vascular maturation. In addition, S1PR1 signaling is important in the regulation of lymphocyte maturation, migration and trafficking. Structure S1PR1 like the other members of the GPCR family is composed of seven-transmembrane helices arranged in a structurally conserved bundle. Like other GPCRs, in the extracellular region S1PR1 is composed of three loops: ECL1 between helices II an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphingosine-1-phosphate Receptor
The sphingosine-1-phosphate receptors are a class of G protein-coupled receptors that are targets of the lipid signalling molecule Sphingosine-1-phosphate (S1P). They are divided into five subtypes: S1PR1, S1PR2, S1PR3, S1PR4 and S1PR5. Discovery In 1990, S1PR1 was the first member of the S1P receptor family to be cloned from endothelial cells. Later, S1PR2 and S1PR3 were cloned from rat brain and a human genomic library respectively. Finally, S1P4 and S1PR5 were cloned from in vitro differentiated human dendritic cells and rat cDNA library. Function The sphingosine-1-phosphate receptors regulate fundamental biological processes such as cell proliferation, angiogenesis, migration, cytoskeleton organization, endothelial cell chemotaxis, immune cell trafficking and mitogenesis. Sphingosine-1-phosphate receptors are also involved in immune-modulation and directly involved in suppression of innate immune responses from T cells. Subtypes Sphingosine-1-phosphate (S1P) receptors ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toll-like Receptor
Toll-like receptors (TLRs) are a class of proteins that play a key role in the innate immune system. They are single-pass membrane protein, single-spanning receptor (biochemistry), receptors usually expressed on sentinel cells such as macrophages and dendritic cells, that recognize structurally conserved molecules derived from Microorganism, microbes. Once these microbes have reached physical barriers such as the skin or intestinal tract mucosa, they are recognized by TLRs, which activate immune cell responses. The TLRs include TLR1, TLR2, TLR3, TLR4, TLR5, TLR6, TLR7, TLR8, TLR9, TLR10, TLR11, TLR12, and TLR13. Humans lack genes for TLR11, TLR12 and TLR13 and mice lack a functional gene for TLR10. The receptors TLR1, TLR2, TLR4, TLR5, TLR6, and TLR10 are located on the cell membrane, whereas TLR3, TLR7, TLR8, and TLR9 are located in Intracellular receptor, intracellular Vesicle (biology and chemistry), vesicles (because they are sensors of nucleic acids). TLRs received their name ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphingolipid
Sphingolipids are a class of lipids containing a backbone of sphingoid bases, which are a set of aliphatic amino alcohols that includes sphingosine. They were discovered in brain extracts in the 1870s and were named after the mythological sphinx because of their enigmatic nature. These compounds play important roles in signal transduction and cell recognition. Sphingolipidoses, or disorders of sphingolipid metabolism, have particular impact on neural tissue. A sphingolipid with a terminal hydroxyl group is a ceramide. Other common groups bonded to the terminal oxygen atom include phosphocholine, yielding a sphingomyelin, and various sugar monomers or dimers, yielding cerebrosides and globosides, respectively. Cerebrosides and globosides are collectively known as glycosphingolipids. Structure The long-chain bases, sometimes simply known as sphingoid bases, are the first non-transient products of '' de novo'' sphingolipid synthesis in both yeast and mammals. These co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SPHK1
Sphingosine kinase 1 is an enzyme that in humans is encoded by the ''SPHK1'' gene. Sphingosine kinase 1 phosphorylates sphingosine to sphingosine-1-phosphate (S1P). SK1 is normally a cytosolic protein but is recruited to membranes rich in phosphatidate (PA), a product of phospholipase D (PLD). Sphingosine-1-phosphate (S1P) is a novel lipid messenger with both intracellular and extracellular functions. Intracellularly, it regulates proliferation and survival, and extracellularly, it is a ligand for EDG1. Various stimuli increase cellular levels of S1P by activation of sphingosine kinase (SPHK), the enzyme that catalyzes the phosphorylation of sphingosine. Competitive inhibitors of SPHK block formation of S1P and selectively inhibit cellular proliferation induced by a variety of factors, including platelet-derived growth factor and serum. Interactions SPHK1 has been shown to interact with TRAF2 TNF receptor-associated factor 2 is a protein that in humans is encoded by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Signaling
In biology, cell signaling (cell signalling in British English) is the Biological process, process by which a Cell (biology), cell interacts with itself, other cells, and the environment. Cell signaling is a fundamental property of all Cell (biology), cellular life in both prokaryotes and eukaryotes. Typically, the signaling process involves three components: the signal, the receptor, and the effector. In biology, signals are mostly chemical in nature, but can also be physical cues such as pressure, Membrane potential, voltage, temperature, or light. Chemical signals are molecules with the ability to bind and activate a specific Receptor (biochemistry), receptor. These molecules, also referred to as Ligand (biochemistry), ligands, are chemically diverse, including ions (e.g. Na+, K+, Ca2+, etc.), lipids (e.g. steroid, prostaglandin), peptides (e.g. insulin, ACTH), carbohydrates, glycosylated proteins (proteoglycans), nucleic acids, etc. Peptide and lipid ligands are particularly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mouse Model
A model organism is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the model organism will provide insight into the workings of other organisms. Model organisms are widely used to research human disease when human experimentation would be unfeasible or unethical. This strategy is made possible by the common descent of all living organisms, and the conservation of metabolic and developmental pathways and genetic material over the course of evolution. Research using animal models has been central to most of the achievements of modern medicine. It has contributed most of the basic knowledge in fields such as human physiology and biochemistry, and has played significant roles in fields such as neuroscience and infectious disease. The results have included the near- eradication of polio and the development of organ transplantation, and have benefited both humans and animals. From 1910 to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atresia
Atresia is a condition in which an orifice or passage in the body is (usually abnormally) closed or absent. Types Anotia Anotia is characterized by the complete absence of the ear and is extremely rare. This condition may affect one or both ears, though one missing ear is more common. Anotia is also linked to conductive hearing loss, a condition in which sound waves do not travel well through the ear and sound is not efficiently conducted from the outer ear canal to the eardrum. Anotia has no known cause. An associated syndrome, such as Treacher Collins or Goldenhar syndrome, may affect up to 40% of patients. Anotia is typically diagnosed through a physical examination at birth. Prenatal ultrasounds may help with early detection. Total ear reconstruction is the standard treatment for Anotia. Biliary atresia Biliary atresia (BA) is a rare disease marked by an unknown-origin biliary obstruction that manifests in the neonatal period. The classic clinical triad of Biliar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Animal Model
An animal model (short for animal disease model) is a living, non-human, often genetic-engineered animal used during the research and investigation of human disease, for the purpose of better understanding the disease process without the risk of harming a human. Although biological activity in an animal model does not ensure an effect in humans, many drugs, treatments and cures for human diseases are developed in part with the guidance of animal models. Animal models representing specific taxonomic groups in the research and study of developmental processes are also referred to as model organisms. There are three main types of animal models: Homologous, Isomorphic and Predictive. Homologous animals have the same causes, symptoms and treatment options as would humans who have the same disease. Isomorphic animals share the same symptoms and treatments, only. Predictive models are similar to a particular human disease in only a couple of aspects. However, these are useful in isolating ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ovarian Follicles
An ovarian follicle is a roughly spheroid cellular aggregation set found in the ovaries. It secretes hormones that influence stages of the menstrual cycle. In humans, women have approximately 200,000 to 300,000 follicles at the time of puberty, each with the potential to release an egg cell (ovum) at ovulation for Human fertilization, fertilization. These eggs are developed once every menstrual cycle The menstrual cycle is a series of natural changes in hormone production and the structures of the uterus and ovaries of the female reproductive system that makes pregnancy possible. The ovarian cycle controls the production and release of eg ... with around 300-400 being ovulated during a woman's reproductive lifetime. Structure Ovarian follicles are the basic units of female reproductive biology. Each of them contains a single oocyte (immature ovum or egg cell). These structures are periodically initiated to grow and develop, culminating in ovulation of usually a single co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphingomyelin
Sphingomyelin (SPH, ) is a type of sphingolipid found in animal cell membranes, especially in the membranous myelin sheath that surrounds some nerve cell axons. It usually consists of phosphocholine and ceramide, or a phosphoethanolamine head group; therefore, sphingomyelins can also be classified as sphingophospholipids. In humans, SPH represents ~85% of all sphingolipids, and typically makes up 10–20 mol % of plasma membrane lipids. Sphingomyelin was first isolated by German chemist Johann L.W. Thudicum in the 1880s. The structure of sphingomyelin was first reported in 1927 as N-acyl-sphingosine-1-phosphorylcholine. Sphingomyelin content in mammals ranges from 2 to 15% in most tissues, with higher concentrations found in nerve tissues, red blood cells, and the ocular lenses. Sphingomyelin has significant structural and functional roles in the cell. It is a plasma membrane component and participates in many signaling pathways. The metabolism of sphingomyelin c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Premature Ovarian Failure
Primary ovarian insufficiency (POI), also called premature ovarian insufficiency and premature ovarian failure, is the partial or total loss of reproductive and hormonal function of the ovaries before age 40 because of follicular ( egg producing area) dysfunction or early loss of eggs. POI can be seen as part of a continuum of changes leading to menopause that differ from age-appropriate menopause in the age of onset, degree of symptoms, and sporadic return to normal ovarian function. POI affects approximately 1 in 10,000 women under age 20, 1 in 1,000 women under age 30, and 1 in 100 of those under age 40. A medical triad for the diagnosis is amenorrhea, hypergonadotropism, and hypoestrogenism. Physical and emotional symptoms are similar to those seen during menopause and can include hot flashes, night sweats, dry skin, vaginal dryness, irregular or absent menstruation, anxiety, depression, mental fog, irritability, nervousness, decreased libido, and increased aut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
