![Structure lysophosphatidylcholine](https://upload.wikimedia.org/wikipedia/commons/b/b5/Structure_lysophosphatidylcholine.svg)
Lysophosphatidylcholines (LPC, lysoPC), also called lysolecithins, are a class of chemical compounds which are derived from
phosphatidylcholine
Phosphatidylcholines (PC) are a class of phospholipids that incorporate choline as a headgroup.
They are a major component of biological membranes and can be easily obtained from a variety of readily available sources, such as egg yolk or soybea ...
s.
Overview
Lysophosphatidylcholines are produced within cells mainly by the enzyme
phospholipase A2, which removes one of the
fatty acid
In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain of an even number of carbon atoms, ...
groups from phosphatidylcholine to produce LPC. Among other properties, they activate endothelial cells during early atherosclerosis.
LPC also acts as a
find-me signal, released by
apoptotic
Apoptosis (from grc, ἀπόπτωσις, apóptōsis, 'falling off') is a form of programmed cell death that occurs in multicellular organisms. Biochemical events lead to characteristic cell changes ( morphology) and death. These changes incl ...
cells to recruit
phagocytes
Phagocytes are cells that protect the body by ingesting harmful foreign particles, bacteria, and dead or dying cells. Their name comes from the Greek ', "to eat" or "devour", and "-cyte", the suffix in biology denoting "cell", from the Greek '' ...
, which then phagocytose the apoptotic cells
Moreover, LPCs can be used in the lab to cause demyelination of brain slices, to mimic the effects of demyelinating diseases such as
multiple sclerosis. Further, they are known to stimulate phagocytosis of the
myelin sheath
Myelin is a lipid-rich material that surrounds nerve cell axons (the nervous system's "wires") to insulate them and increase the rate at which electrical impulses (called action potentials) are passed along the axon. The myelinated axon can be l ...
and can change the surface properties of
erythrocytes
Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus in red blood cells), haematids, erythroid cells or erythrocytes (from Greek ''erythros'' for "red" and ''kytos'' for "holl ...
.
LPC-induced demyelination is thought to occur through the actions of recruited
macrophages
Macrophages (abbreviated as M φ, MΦ or MP) ( el, large eaters, from Greek ''μακρός'' (') = large, ''φαγεῖν'' (') = to eat) are a type of white blood cell of the immune system that engulfs and digests pathogens, such as cancer ce ...
and
microglia which
phagocytose
Phagocytosis () is the process by which a cell uses its plasma membrane to engulf a large particle (≥ 0.5 μm), giving rise to an internal compartment called the phagosome. It is one type of endocytosis. A cell that performs phagocytosis is ...
nearby
myelin
Myelin is a lipid-rich material that surrounds nerve cell axons (the nervous system's "wires") to insulate them and increase the rate at which electrical impulses (called action potentials) are passed along the axon. The myelinated axon can be ...
. Invading T cells are also thought to mediate this process.
Bacteria such as Legionella pneumophila utilize phospholipase A2 end-products (fatty acids and
lysophospholipid
The lysophospholipid receptor (LPL-R) group are members of the G protein-coupled receptor family of integral membrane proteins that are important for lipid signaling. In humans, there are eight LPL receptors, each encoded by a separate gene. Th ...
s) to cause host cell (macrophage) apoptosis through cytochrome C release.
LPCs are present as minor phospholipids in the
cell membrane
The cell membrane (also known as the plasma membrane (PM) or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of all cells from the outside environment ( ...
(≤ 3%) and in the
blood plasma
Blood plasma is a light amber-colored liquid component of blood in which blood cells are absent, but contains proteins and other constituents of whole blood in suspension. It makes up about 55% of the body's total blood volume. It is the intr ...
(8–12%).
Since LPCs are quickly metabolized by
lysophospholipase
The enzyme lysophospholipase (EC 3.1.1.5) catalyzes the reaction
:2-lysophosphatidylcholine + H2O \rightleftharpoons glycerophosphocholine + a carboxylate
This enzyme belongs to the family of hydrolases, specifically those acting on carboxylic ...
and
LPC-acyltransferase, they last only shortly ''in vivo''. By replacing the
acyl-group within the LPC with an
alkyl-group,
alkyl-lysophospholipids (ALP) were synthesized. These LPC analogues are metabolically stable, and several such as
edelfosine,
miltefosine
Miltefosine, sold under the trade name Impavido among others, is a medication mainly used to treat leishmaniasis and free-living amoeba infections such as ''Naegleria fowleri'' and '' Balamuthia mandrillaris''. This includes the three forms of l ...
and
perifosine
Perifosine (also KRX-0401) is a former drug candidate that was under development for a variety of cancer indications. It is an alkyl- phospholipid structurally related to miltefosine. Perifosine interrupts the PI3K/AKT/mTOR pathway by acting as a ...
are under research and development as drugs against cancer and other diseases.
Lysophosphatidylcholine processing has been discovered to be an essential component of normal human brain development: those born with genes that prevent adequate uptake suffer from lethal microcephaly.
MFSD2a has been shown to transport LPC-bound polyunsaturated fatty acids, including DHA and EPA, across the blood-brain and blood-retinal barriers.
LPCs occur in many foods naturally. In Starch: Chemistry and Technology third edition on page 592, the authors state that "lysophosphatidylcholine makes up about 70% of the lipids in oat starch".
The anti-cancer abilities of synthetic LPC variants are special since they do not target the cell DNA but insert into the plasma membrane and cause
apoptosis through influencing several signal pathways. Therefore, their effects are independent of the proliferation state of the
tumor
A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...
cell.
Industrial Applications of Enzymes Producing Lysophosphatidylcholine
FoodPro LysoMaxa Oil is an FDA approved commercialized PLA2 enzyme preparation utilized for the degumming of vegetable oils in large-scale productions to increase yield. Variants of lysophosphatidylcholine are the main products of this enzyme.
Lysophosphatidylcholine has been studied as an immune activator for differentiating monocytes to mature dendritic cells. Lysophosphatidylcholine present in blood amplifies microbial TLR ligands induced inflammatory responses from human cells like intestinal epithelial cells and macrophages/monocytes. This has an implication in sepsis induced by microbes.
Composition in Foods
Lysophosphatidylcholine accounts for 4.6% of phospholipids found in coconut oil, which make up 0.2% of lipids in coconut oil. This is compared to vegetable oils, which may contain 2-3% phospholipids.
Lysophosphatidylcholine and Atherosclerosis
Intima-media thickness, which is positively correlated with reduced blood flow, was studied in young smokers. Evidence pointed towards smoking as a major risk factor for increased levels of PLA2, due to tobacco smoke's impact on oxidation of retained LDL particles in the intima of a carotid artery.
which may have a detrimental impact on overall health.
See also
*
1-Lysophosphatidylcholine
References
{{PAF signaling
Lipids
Organophosphates