Navigation Links
Genetic disorder sheds light on enzyme's role in bone metabolism
Date:11/4/2008

Pycnodysostosis, a condition from which the painter Henri de Toulouse-Lautrec suffered, is a genetic disease characterized by short stature. This rare disease, surprisingly, provides a window into how joints are destroyed by arthritis. It is caused by deficiency of an enzyme known as cathepsin K which hampers osteoclasts (the cells that break down bone in bone modeling and repair), leading to poor bone resorption and dense, brittle bones.

Cathepsin K's role in bone metabolism has largely been studied using mouse models, but a new study examines the enzyme's role in bone resorption in a human patient and shows that it is not required to break down bone. The study was published in the November issue of Arthritis & Rheumatism (http://www3.interscience.wiley.com/journal/76509746/home).

Led by Professor Yrj T. Konttinen of Helsinki University Central Hospital in Helskinki, Finland , the study involved a 55-year-old female patient with pycnodysostosis who also developed psoriatic arthritis. Since the patient lacked cathepsin K due to her condition, researchers hypothesized that this would protect her from the bone erosions in the hands and feet normally seen in psoriatic arthritis. However, she did in fact develop extensive erosions and destructive bone changes in her hands. Blood analysis was conducted to examine the proteinases (enzymes that break down proteins) responsible for bone degradation as well as the cellular mechanisms of bone resorption.

The analyses showed that the osteoclasts formed by the patient lacked cathepsin K, which was expected. Surprisingly, however, this deficiency did not prevent cells from resorbing bone, although the resorption was abnormal. In bone resorption, osteoclasts attach to the bone and dissolve bone mineral in the matrix, a process that appears to proceed normally even in pycnodysostosis. In a second step, known as collagenolysis, peptide bonds in the collagen of the demineralized bone matrix are broken down. The authors expected that this step would be defective in the cells of a patient who lacked cathepsin K, but instead found that it was not, since the patient's osteoclasts showed evidence of bone resorption.

"The results of our study indicate that, against the dogma, cathepsin K is not necessary for osteoclast-mediated bone resorption," the authors state. "The present results and some very recent findings suggest that even total inhibition of cathepsin K does not protect against pathologic bone destruction in arthritis." This indicates that other proteinases may play a role in bone collagen destruction when cathepsin K is not present. The authors conclude: "These findings may be pertinent to our understanding of the functions of cathepsin K inhibitors, which are currently being developed as drugs to treat metabolic bone diseases.


'/>"/>

Contact: Sean Wagner
swagner@wiley.com
781-388-8550
Wiley-Blackwell
Source:Eurekalert

Related medicine news :

1. Penn scientists map molecular regulation of fat-cell genetics
2. Tackling a hard-to-treat childhood cancer by targeting epigenetic changes
3. Tackling Hard-to-treat Childhood Cancer by Targeting Epigenetic Changes
4. Interleukin Genetics to Present at Rodman & Renshaw 10th Annual Healthcare Conference
5. First evidence that prenatal exposure to famine may lead to persistent epigenetic changes
6. If the diabetes has a direct carcinogenetic effect?
7. Genetic Approach Boosts Yeast Infection Treatment
8. Breakthrough Baldness Genetic Test
9. New Genetic Links to Baldness Discovered
10. Genetic Research Offers Insights Into Form of Malaria
11. deCODE Launches deCODE BreastCancer(TM), a Genetic Test to Screen for Risk of the Common Forms of Breast Cancer
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:5/26/2016)... (PRWEB) , ... May 26, 2016 , ... According to ... In an industry filled with chemical-laden beauty products, one company is going against the ... for you: Mad Hippie. The rising star in the green space is proud to ...
(Date:5/26/2016)... Lake MN (PRWEB) , ... May 26, 2016 , ... ... Stance Angle chair , furniture that may support women during pregnancy. Potential benefits ... legs and feet, improved rest and comfort and healthier levels of sitting and standing. ...
(Date:5/25/2016)... (PRWEB) , ... May 26, 2016 , ... The United ... treatment of androgenetic alopecia in both men and women. To date, the company is ... with FDA clearance for any adult who suffers with androgenetic alopecia. , “This ...
(Date:5/25/2016)... ... May 25, 2016 , ... “We ... Managing Partner at HealthScape Advisors. “Brad brings significant experience advising healthcare provider clients ... system accelerates with the implementation of MACRA, we believe that continuing to add ...
(Date:5/25/2016)... Kansas City, MO (PRWEB) , ... May 25, 2016 , ... ... professional, collegiate, and amateur athletics, The National Center for Drug Free Sport (Drug Free ... Drug Free Sport”. This conference, to be held July 12 – 13 in Kansas ...
Breaking Medicine News(10 mins):
(Date:5/25/2016)... , Germany and ... QIAGEN N.V. (NASDAQ: QGEN ; Frankfurt Prime ... a licensing and co-development agreement with Therawis Diagnostics GmbH to ... will be to develop and market PITX2 as a marker ... other high-risk breast cancer patients. "We are pleased ...
(Date:5/25/2016)... 2016 According to market research ... and Demand Forecast to 2022 - Industry Insights by ... published by P&S Market Research, the global insulin delivery ... and it is expected to grow at a CAGR ... pump segment is expected to witness the fastest growth ...
(Date:5/25/2016)... Texas , May 25, 2016 ... the issuance to it by the US Patent ... The company,s technology includes proprietary processes for electronic ... for health and wellness programs, HIPAA compliance and ... "Our technology ...
Breaking Medicine Technology: