Navigation Links
Researchers discover hereditary enzyme deficiency
Date:6/13/2012

An international research team headed by Professor Dr. Thomas Dierks at Bielefeld University has discovered a hereditary enzyme deficiency. It is a subform of the mucopolysaccharidosis syndrome and has been termed MPS IIIE or after its discoverer 'Dierks's disorder'. It leads to a progressive loss of mental abilities in mice, particularly to learning and coordination difficulties along with forgetfulness. The biochemist Dierks and his team have not only identified the disorder but also developed a treatment concept. Their findings are being published this week (CW 24) in the renowned journal 'Proceedings of the National Academy of Sciences of the USA' (PNAS).

Enzymes control the constitution and degradation of nutrient and messenger substances in the human body. If the body produces a defective enzyme due to an inherited deficiency, this control breaks down. The individual becomes ill because, for example, substances can no longer be degraded and accumulate in the body.

Dierks and his colleagues have discovered that a deficiency of the enzyme arylsulfatase G (ARSG) triggers the disease MPS IIIE in mice. Actually, the enzyme among others - is responsible for degrading the carbohydrate heparan sulfate. This process occurs within the cells inside the lysosomes. These 'recycling plants' in the cells break down no longer needed heparan sulfate molecules into their smallest components, which later are used to reassemble new molecules.

Heparan sulfate is a long-chain molecule. This chain can only be broken down from one end and only step by step. This process is performed by various enzymes including ARSG. If one of the enzymes is deficient because of a genetic defect, the complete degradation process comes to a stop. The molecular chains remain largely intact and accumulate more and more in the lysosome, which finally stops functioning. Then, also other substances such as proteins and lipids also accumulate because they are no longer degraded. The lysosome grows and grows until it damages the entire cell and eventually destroys it.

At the beginning of the study (2003), only seven of the enzymes involved in the degradation of heparan sulfate were known. Dierks and his team were searching specifically for one missing enzyme. They knew that a total of at least nine different enzymes would be needed for the complete degradation of heparan sulfate two of these (both of them sulfatases) had still not been discovered. Every inherited deficiency in one of these enzymes corresponds to a disorder belonging to the mucopolysaccharidosis syndrome. 'When we started the study, we suspected that arylsulfatase G was involved in the degradation of heparan sulfate', says Dierks. To test this assumption, his team bred mice in which arylsulfatase G was deficient. Their suspicion was confirmed: With increasing age, the mice revealed high concentrations of heparan sulfate in the brain, the liver, and the kidneys. Professor Jeffrey D. Esko from the University of California San Diego (USA) is also working in this project. He and his team analysed tissue samples with a mass spectrometer and confirmed the finding that the blocked cleavage of a specific sulfate group is the cause of the accumulation of heparan sulfate.

Using behaviour tests, Dierks's team found that mice with an ARSG deficiency suffer from cognitive problems once they reach the age of 12 months. If they enter an open field, they stick to the safer periphery and, unlike healthy littermates, do not have the courage to explore the centre. They also fail to master a water maze. For a long time, the mice had been trained successfully to swim through a pool filled with a milky liquid until they found a platform hidden beneath its surface. However, as soon as they were 12 months old, the mice failed to memorize where the platform was located. They took much longer than before to discover it. Younger and healthy mice had no problems in finding the platform again. The defect is in the brain. In a study of tissue samples from the animals' cerebellum, the research team showed that through the accumulation of heparan sulfate, the Purkinje cells in the cerebellum die off and accompanied by inflammation are replaced by new cells. However, according to Dierks, these glia cells have only a supporting function and do not form any new connections to nerve cells.

A major success for the researchers is that their findings can be used to develop a treatment for this hereditary disorder and test this treatment on ARSG deficient mice. They are producing ARSG enzyme in a biotechnology process with the help of genetically modified cell cultures. In sick mice that are regularly injected with a solution containing the enzyme, further damage to their organs should be stopped, Dierks believes. Similar treatments are successfully applied to patients with other mucopolysaccharidosis disorders. 'The biochemical processes underlying such lysosomal storage disorders are principally the same in all mammals. However, effects are more severe in human beings because of their greater life span', says Dierks. An early diagnosis of these disorders can be difficult because the onset is frequently insidious. Sometimes, the disorder can only be recognized through its symptoms in adolescence. And then the diagnosis is difficult for a physician, Thomas Dierks says, 'because systematic screenings are performed only in childhood, and one does not initially consider a genetic cause. However, treatment has to start as early as possible'. 'Dierks's disorder' can be diagnosed unequivocally with a mass spectrometer the researchers have developed their own procedure for this.


'/>"/>

Contact: Prof. Dr. Thomas Dierks
thomas.dierks@uni-bielefeld.de
49-521-106-2092
University of Bielefeld
Source:Eurekalert  

Related biology technology :

1. New England Biolabs Introduces Polbase, an Information Repository of Scientific Data for Polymerase Researchers
2. In new quantum-dot LED design, researchers turn troublesome molecules to their advantage
3. Multidisciplinary team of researchers develop world’s lightest material
4. Researchers shrink tumors and minimize side effects using tumor-homing peptide to deliver treatment
5. Innovative MetaMorph® NX Software Shatters Barriers Between Researchers and Image Analysis Goals with Exclusive Visual Workflow
6. UCLA researchers demonstrate fully printed carbon nanotube transistor circuits for displays
7. Penn and Brown researchers demonstrate earthquake friction effect at the nanoscale
8. Two Top Biological Imaging Centers Offer Powerful Free Online Tool to Researchers, Educators, and Public
9. Researchers develop one of the worlds smallest electronic circuits
10. MU researchers identify key plant immune response in fight against bacteria
11. Researchers realize high-power, narrowband terahertz source at room temperature
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Researchers discover hereditary enzyme deficiency
(Date:6/23/2016)... 2016 A person commits a crime, and the ... track the criminal down. An outbreak of foodborne ... Administration (FDA) uses DNA evidence to track down the bacteria ... far-fetched? It,s not. The FDA has increasingly used a complex, ... foodborne illnesses. Put as simply as possible, whole genome sequencing ...
(Date:6/23/2016)... , June 23, 2016   EpiBiome , a ... $1 million in debt financing from Silicon Valley Bank ... automation and to advance its drug development efforts, as ... facility. "SVB has been an incredible strategic ... services a traditional bank would provide," said Dr. ...
(Date:6/23/2016)... NEWPORT BEACH, Calif. , June 23, 2016 /PRNewswire/ ... offering new biological discoveries to the medical community, has ... and co-founder Matthew Nunez . "We ... provide us with the capital we need to meet ... funding will essentially provide us the runway to complete ...
(Date:6/23/2016)... ... June 23, 2016 , ... Velocity Products, a ... designed, tuned and optimized exclusively for Okuma CNC machining centers at The International ... a collaboration among several companies with expertise in toolholding, cutting tools, machining dynamics ...
Breaking Biology Technology:
(Date:4/15/2016)... -- A new partnership announced today will help life ... a fraction of the time it takes today, ... insurance policies to consumers without requiring inconvenient and ... rapid testing (A1C, Cotinine and HIV) and higi,s ... pulse, BMI, and activity data) available at local ...
(Date:3/31/2016)...   LegacyXChange, Inc. ... LegacyXChange is excited to release its first ... be launched online site for trading 100% guaranteed authentic ... also provide potential shareholders a sense of the value ... industry that is notorious for fraud. The video is ...
(Date:3/22/2016)... India , March 22, 2016 /PRNewswire/ ... market research report "Electronic Sensors Market for Consumer ... Proximity, & Others), Application (Communication & IT, ... Geography - Global Forecast to 2022", published ... industry is expected to reach USD 26.76 ...
Breaking Biology News(10 mins):