Phospholipidosis is a lysosomal storage disorder characterized by the excess accumulation of phospholipids in tissues. [1] [2] [3] Certain cases may be triggered by medications. [4]
The traditional method to evaluate drug-induced phospholipidosis (DIPL) is visual confirmation of myeloid bodies in tissues by electron microscopy. Electron microscopy has limited utility to monitor DIPL in humans because of the invasive nature of acquiring patient tissue biopsy samples. A qualified biomarker of DIPL in the blood or urine is needed to provide a more routine, non-invasive, and cost effective means to monitor DIPL in the clinic. [5]
A lysosome is a membrane-bound organelle found in many animal cells. They are spherical vesicles that contain hydrolytic enzymes that can break down many kinds of biomolecules. A lysosome has a specific composition, of both its membrane proteins, and its lumenal proteins. The lumen's pH (~4.5–5.0) is optimal for the enzymes involved in hydrolysis, analogous to the activity of the stomach. Besides degradation of polymers, the lysosome is involved in various cell processes, including secretion, plasma membrane repair, apoptosis, cell signaling, and energy metabolism.
Proteomics is the large-scale study of proteins. Proteins are vital parts of living organisms, with many functions such as the formation of structural fibers of muscle tissue, enzymatic digestion of food, or synthesis and replication of DNA. In addition, other kinds of proteins include antibodies that protect an organism from infection, and hormones that send important signals throughout the body.
Gaucher's disease or Gaucher disease (GD) is a genetic disorder in which glucocerebroside accumulates in cells and certain organs. The disorder is characterized by bruising, fatigue, anemia, low blood platelet count and enlargement of the liver and spleen, and is caused by a hereditary deficiency of the enzyme glucocerebrosidase, which acts on glucocerebroside. When the enzyme is defective, glucocerebroside accumulates, particularly in white blood cells and especially in macrophages. Glucocerebroside can collect in the spleen, liver, kidneys, lungs, brain, and bone marrow.
Lysosomal storage diseases are a group of over 70 rare inherited metabolic disorders that result from defects in lysosomal function. Lysosomes are sacs of enzymes within cells that digest large molecules and pass the fragments on to other parts of the cell for recycling. This process requires several critical enzymes. If one of these enzymes is defective due to a mutation, the large molecules accumulate within the cell, eventually killing it.
Steatotic liver disease (SLD) a.k.a. fatty liver disease (FLD) or hepatic steatosis, is a condition where excess fat builds up in the liver. Often there are no or few symptoms. Occasionally there may be tiredness or pain in the upper right side of the abdomen. Complications may include cirrhosis, liver cancer, and esophageal varices.
Tachykinin peptides are one of the largest families of neuropeptides, found from amphibians to mammals. They were so named due to their ability to rapidly induce contraction of gut tissue. The tachykinin family is characterized by a common C-terminal sequence, Phe-X-Gly-Leu-Met-NH2, where X is either an Aromatic or an Aliphatic amino acid. The genes that produce tachykinins encode precursor proteins called preprotachykinins, which are chopped apart into smaller peptides by posttranslational proteolytic processing. The genes also code for multiple splice forms that are made up of different sets of peptides.
Enzyme replacement therapy (ERT) is a medical treatment which replaces an enzyme that is deficient or absent in the body. Usually, this is done by giving the patient an intravenous (IV) infusion of a solution containing the enzyme.
β-Glucocerebrosidase is an enzyme with glucosylceramidase activity that cleaves by hydrolysis the β-glycosidic linkage of the chemical glucocerebroside, an intermediate in glycolipid metabolism that is abundant in cell membranes. It is localized in the lysosome, where it remains associated with the lysosomal membrane. β-Glucocerebrosidase is 497 amino acids in length and has a molecular mass of 59,700 Da.
Transcytosis is a type of transcellular transport in which various macromolecules are transported across the interior of a cell. Macromolecules are captured in vesicles on one side of the cell, drawn across the cell, and ejected on the other side. Examples of macromolecules transported include IgA, transferrin, and insulin. While transcytosis is most commonly observed in epithelial cells, the process is also present elsewhere. Blood capillaries are a well-known site for transcytosis, though it occurs in other cells, including neurons, osteoclasts and M cells of the intestine.
Kininogens are precursor proteins for kinins, biologically active polypeptides involved in blood coagulation, vasodilation, smooth muscle contraction, inflammatory regulation, and the regulation of the cardiovascular and renal systems.
Rupatadine is a second generation antihistamine and platelet-activating factor antagonist used to treat allergies. It was discovered and developed by Uriach and is marketed as Rupafin and under several other trade names.
Ambroxol is a drug that breaks up phlegm, used in the treatment of respiratory diseases associated with viscid or excessive mucus. Ambroxol is often administered as an active ingredient in cough syrup.
Exosomes are membrane-bound extracellular vesicles (EVs) that are produced in the endosomal compartment of most eukaryotic cells. In multicellular organisms, exosomes and other EVs are found in biological fluids including saliva, blood, urine and cerebrospinal fluid. EVs have specialized functions in physiological processes, from coagulation and waste management to intercellular communication.
Class III β-tubulin, otherwise known as βIII-tubulin (β3-tubulin) or β-tubulin III, is a microtubule element of the tubulin family found almost exclusively in neurons, and in testis cells. In humans, it is encoded by the TUBB3 gene.
Surinabant (SR147778) is a cannabinoid receptor type 1 antagonist developed by Sanofi-Aventis. It is being investigated as a potential treatment for nicotine addiction, to assist smoking cessation. It may also be developed as an anorectic drug to assist with weight loss, however there are already several CB1 antagonists or inverse agonists on the market or under development for this application, so surinabant is at present mainly being developed as an anti-smoking drug, with possible application in the treatment of other addictive disorders such as alcoholism. Other potential applications such as treatment of ADHD have also been proposed.
ELB-139 (LS-191,811) is an anxiolytic drug with a novel chemical structure, which is used in scientific research. It has similar effects to benzodiazepine drugs, but is structurally distinct and so is classed as a nonbenzodiazepine anxiolytic.
Leteprinim is a hypoxanthine derivative drug with neuroprotective and nootropic effects. It stimulates release of nerve growth factors and enhances survival of neurons in the brain, and is under development as a potential treatment for neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease and stroke.
Pimavanserin, sold under the brand name Nuplazid, is an atypical antipsychotic which is approved for the treatment of Parkinson's disease psychosis and is also being studied for the treatment of Alzheimer’s disease psychosis, schizophrenia, agitation, and major depressive disorder. Unlike other antipsychotics, pimavanserin is not a dopamine receptor antagonist.
Substrate reduction therapy offers an approach to treatment of certain metabolic disorders, especially glycogen storage diseases and lysosomal storage disorders. In a storage disorder, a critical failure in a metabolic pathway prevents cellular breakdown and disposal of some large molecule. If residual breakdown through other pathways is insufficient to prevent harmful accumulation, the molecule accumulates in the cell and eventually interferes with normal biological processes. Examples of lysosomal storage disorders include Gaucher's disease, Tay–Sachs disease, Sandhoff disease, and Sanfilippo syndrome.
LG-120907 is a nonsteroidal antiandrogen (NSAA) of the quinoline group which was developed by Ligand Pharmaceuticals along with selective androgen receptor modulators (SARMs) like LG-121071 and was never marketed. The drug is a high-affinity antagonist of the androgen receptor (AR) with a Ki value of 26 nM and has been found to inhibit growth of the ventral prostate and seminal vesicles in male rats without increasing circulating levels of luteinizing hormone or testosterone. However, this tissue selectivity has not been assessed in humans. LG-120907 is orally active and shows greater oral potency than the arylpropionamide NSAA flutamide.