How does Pompe disease affect lysosomes?
Pompe disease is a lysosomal storage disorder in which acid alpha-glucosidase (GAA) is deficient or absent. Deficiency of this lysosomal enzyme results in progressive expansion of glycogen-filled lysosomes in multiple tissues, with cardiac and skeletal muscle being the most severely affected.
How does the change in the lysosome structure and function result in the symptoms of Pompe disease?
Mutations in the GAA gene prevent acid alpha-glucosidase from breaking down glycogen effectively, which allows this sugar to build up to toxic levels in lysosomes. This buildup damages organs and tissues throughout the body, particularly the muscles, leading to the progressive signs and symptoms of Pompe disease.
Is Pompe disease a lysosomal disorder?
The human body can be seen as an assembly of interconnecting organs. Organs are composed of organ specific tissues, and tissues are composed of specialized cells like muscle cells, nerve cells, etc. Pompe disease belongs to a group of diseases known as the ‘lysosomal storage disorders’ (LSDs).
What organelle does Pompe disease affect in the cell?
The defect results in a build-up of glycogen in the lysosome, a saclike storage organelle in the cell that acts as a waste-disposal system, leading to muscle weakness, organ damage including the brain, and possible death.
What causes lysosomes to malfunction?
A defective gene that develops during fetal (before birth) growth causes lysosomal storage diseases. Children can inherit the gene from one or both parents. The defective gene regulates a particular enzyme in the lysosome, which either is missing or isn’t enough to process the excess substances.
What enzyme is defective in Pompe disease?
Pompe disease is a rare (estimated at 1 in every 40,000 births), inherited and often fatal disorder that disables the heart and skeletal muscles. It is caused by mutations in a gene that makes an enzyme called acid alpha-glucosidase (GAA).
What enzyme is affected by Pompe disease?
How does Pompe disease work?
Pompe disease happens when your body can’t make a protein that breaks down a complex sugar, called glycogen, for energy. Too much sugar builds up and damages your muscles and organs. Pompe disease causes muscle weakness and trouble breathing. It mostly affects the liver, heart, and muscles.
How does lysosomes destruction affect the cell?
Lysosomes are involved with various cell processes. They break down excess or worn-out cell parts. They may be used to destroy invading viruses and bacteria. If the cell is damaged beyond repair, lysosomes can help it to self-destruct in a process called programmed cell death, or apoptosis.
What happens when lysosomes are damaged?
When lysosomes don’t work properly, these sugars and fats build up in the cell instead of being used or excreted. Lysosomal storage diseases are rare, but can lead to death if untreated.
What diseases affect lysosomes?
Types of Lysosomal Storage Diseases?
- Gaucher disease.
- Niemann-Pick disease.
- Fabry disease.
- Tay-Sachs disease.
- Mucopolysaccharidoses (MPS) diseases.
- Pompe disease.
Are there any diseases associated with lysosomes?
Gaucher disease is one of the most common lysosomal storage disorders (LSDs). LSDs are inherited disorders resulting from a lack of specific enzymes that break down certain lipids (fats) or carbohydrates (sugars) in the body cells.
Is glycogen stored in lysosomes?
8. Muscular dysfunction in GSD II. GSD II is the result of a genetic defect in the acid 1-4 α-glucosidase gene resulting in an insufficient degradation of glycogen inside the lysosomes. From an energetic point of view, the amount of glycogen accumulating within the lysosomes is inconsequential.
What is lysosomal glycogen?
Author Summary. Lysosomes are organelles that work as a disposal system for the cell. It is known that lysosomes can degrade glycogen and that defects in this function trigger the accumulation of vesicles containing glycogen in animals that lead to vacuolar myopathies—diseases that result in muscle weakness.
What enzyme is affected in Pompe disease?
What can happen when a lysosomes burst inside the cell and all its enzymes are released in the cytoplasm?
If a lysosome were to burst and release proteases, lipases, and nucleases into the cytoplasm, then the cell would be destroyed if these enzymes remained active. However, these proteins will be folded incorrectly at pH 7.2, and therefore, they will be inactive.
What might be the cause of the lysosome malfunction?
In each case, lysosomal storage diseases are caused by an inborn error of metabolism that results in the absence or deficiency of an enzyme, leading to the inappropriate storage of material in various cells of the body. Most lysosomal storage disorders are inherited in an autosomal recessive manner.
What diseases are associated with lysosomes?
What causes lysosomes to rupture?
Furthermore, pathogens (bacteria and viruses), neurotoxic aggregates and silica crystals can rupture lysosomes. In addition, known cell-death mediators, such as Bcl-2 family proteins, p53 or calpains (which induce mitochondrial membrane permeabilization), can also affect lysosome integrity.
What is lysosomal enlargement/rupture in Pompe disease?
Lysosomal enlargement/rupture has long been considered a mechanism of relentless muscle damage in Pompe disease. In past years, it became clear that this simple view of the pathology is inadequate; the pathological cascade involves dysfunctional autophagy, a major lysosome-dependent intracellular degradative pathway.
What is the pathophysiology of Pompe disease?
Pompe disease, also known as glycogen storage disease type II (GSDII) or “acid maltase deficiency”, is caused by the absence or deficiency of acid alpha-glucosidase (GAA), a lysosomal enzyme that is responsible for the cleavage of the α-1,4- and α-1,6-glycosidic bonds of glycogen to glucose.
What’s new in Pompe disease treatment?
Several new therapeutic approaches have been tested in Pompe mouse models: substrate reduction therapy, lysosomal exocytosis following the overexpression of transcription factor EB and a closely related but distinct factor E3, and genetic manipulation of autophagy. Keywords: autophagy, lysosome, Pompe disease, lipofuscin, enzyme replacement therapy
What is the history of Pompe syndrome?
In 1932, Johannes Cassianus Pompe, a Dutch pathologist, described the disease in a 7-month-old infant who died of idiopathic hypertrophy of the heart; in addition to the cardiac problems, the infant had generalized muscle weakness. Dr.