OU-MRU Vol.11 May 2015

Okayama University Medical Research Updates （OU-MRU）

2015.05 Vol.11

Source: Okayama University, Center for Public Affairs and Communications

For immediate release: 30 May 2015
Okayama University research: Compound-protein combination shows promise for arthritis
treatment(Okayama, 30 May) Screening over 700 compounds reveals a steroid hormone with thecapability to promote the repair of cartilage in joints.

Damaged cartilage leads to pain and reduced joint mobility in millions of arthritis sufferers
worldwide, yet there remains a lack of effective treatments. Now Emilio Satoshi and TakuoKaboki and colleagues at Okayama University Graduate School of Medicine, the National
Institutes of Health in the US and Harvard School of Dental Medicine identify a steroid
hormone that could help cartilage development - ‘chondrogenesis’ – thereby regenerating
the damaged joint tissue.

The researchers screened cultures of cartilage stem cells with over 700 compounds forsubstances associated with chondrogenesis, and identified enhancements to thesesubstances in the presence of the steroid hormone fluocinolone acetonide (FA). The
researchers then studied cultures of the stem cells that develop into bone and cartilage cells
in cultures of FA and transforming growth factor beta 3 (TGF-β3). Previous studies havereported that TGF-β3 plays an important role in chondrogenesis, but antagonistic effects on
the development and proliferation of cartilage cells have also been observed, particularly inthe presence of certain other bioactive proteins.

In experiments in vitro the researchers found that both TGF-β3 and FA inhibit
chondrogenesis, but when present together they upregulate both a key marker and aregulator for chondrocytes. Further experiments highlighted the cellular pathways for theenhanced activity.

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OU-MRU Vol.11 May 2015

In addition the researchers confirmed the effects of the combined compounds inexperiments with mice. “The in vivo cartilage repair model confirmed that FA/TGF-β3 is
uniquely able to promote cartilage repair,” report the researchers. They add that thecombination could have potential for clinical applications based on the development ofstem cells into cartilage cells.

Background
Chondrogenesis
The only cells that exist in healthy cartilage are chondrocytes. Previous efforts to promotechondrogenesis using growth factors, gene therapy and compounds have had limited
success as the cartilage does not readily regenerate. Harnessing the ability to develop
cartilage cells from stem cells offers a promising approach to aiding cartilage regeneration
but has not yet been achieved.

Previous research has pointed towards transforming growth factor beta and insulin-likegrowth factors as the main contributors towards chondrogenesis. This suggests that somecombination of these proteins would enhance differentiation of human bone marrowstem/progenitor cells (hBMSCs) - the stem cells that develop into bone and cartilage cells.
However previous experiments to study the effects of different combinations of these
proteins revealed antagonistic effects on chondrogenesis.

The screening tests
The researchers screened a Food and Drug Administration (FDA)-approved drug library
containing 640 compounds and an orphan ligand library containing 84 compounds. They
checked the cultures of the compounds for the presence of the promoter for a gene of a
type of collagen that makes up the majority of the cartilage protein in joints (Col2a1promoter), as well as a known marker (Acan) and a known regulator of chondrocytes (Sox9).

They found 86 compounds that enhance Col2a1 promoter, 8 that regulated Acan but just
one that upregulated Sox9 as well, that is, FA. FA is a gluococorticoid, a type of hormonethat takes its name from its steroid structure, its role in glucose metabolism, and because it
is synthesised in the adrenal cortex and plays an important.

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OU-MRU Vol.11 May 2015

Clinical use of glucocorticoids
Glucocorticoids are already used for clinical applications. FA is currently mainly used fordermal, dental and ophthalmological prescriptions and TA and DEX, which have similar
structures, have already been used in injections for the management of joint diseases. Whileglucocorticoid injections are widely used to treat in rheumatoid arthritis and other joint
diseases, they have been recognised as harmful to cartilage over prolonged use, possibly
due to inhibiting effects on the development of cartilage cells from stem cells. Investigationof alternative glucocorticoids may decrease cartilage damage from long-term use.

The researchers found that FA/TMFβ3 enhanced chondrogenesis by enhancing the activityof the mTORC1/AKT pathway. As AKT inhibitors have been used as a chemotherapeutic
treatment for tumors, exploitation of these effects to treat arthritis will require caution.

Figure caption
Among glucocorticoids, FA/TGF-β3 is uniquely able to promote articular surface
regeneration. Substantial cartilage repair of the knee joints in mice was observed only in thegroup transplanted with hBMSCs treated with FA/TGF-β3. Arrowheads show the borders ofthe surgical defect. The asterisk shows the regenerated superficial layer of the articular

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OU-MRU Vol.11 May 2015

cartilage only in FA/TGF-β3 group. Arrows indicate articular surface damage in the groups
that received TA/TGF-β3-treated hBMSCs.

Reference
Emilio Satoshi Hara, Mitsuaki Ono, Pham Thanh Hai, Wataru Sonoyama, Satoshi Kubota,
Masaharu Takigawa, Takuya Matsumoto, Marian F. Young, Bjorn R. Olsen, Takuo Kuboki.
Fluocinolone acetonide is a potent synergistic factor of TGF-β3-associated chondrogenesisof bone marrow-derived mesenchymal stem cells for articular surface regeneration. Journalof Bone and Mineral Research, 2015.
DOI: 10.1002/jbmr.2502
http://onlinelibrary.wiley.com/doi/10.1002/jbmr.2502/abstract

Correspondence toProfessor and Chair Takuo Kuboki, D.D.S., Ph.D.
Department of Oral Rehabilitation and Regenerative Medicine
Okayama University Graduate School of Medicine, Dentistry andPharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama-shi,Okayama-ken, 700-8525, Japan.
E-mail: kuboki@md.okayama-u.ac.jp

Prof.Kuboki (R)Further information
Okayama University
1-1-1 Tsushima-naka , Kita-ku , Okayama 700-8530, Japan
Planning and Public Information Division, Okayama University
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OU-MRU Vol.11 May 2015

Okayama University Medical Research Updates （OU-MRU）
Vol.1：Innovative non-invasive ‘liquid biopsy’ method to capture circulating tumor cells
from blood samples for genetic testing
Vol.2：Ensuring a cool recovery from cardiac arrest
Vol.3：Organ regeneration research leaps forward
Vol.4：Cardiac mechanosensitive integrator
Vol.5：Cell injections get to the heart of congenital defects
Vol.6：Fourth key molecule identified in bone development
Vol.7：Anticancer virus solution provides an alternative to surgery
Vol.8：Light-responsive dye stimulates sight in genetically blind patients
Vol.9：Diabetes drug helps towards immunity against cancer
Vol.10：Enzyme-inhibitors treat drug-resistant epilepsy

About Okayama UniversityOkayama University is one of the largest
comprehensive universities in Japan withroots going back to the Medical Training
Place sponsored by the Lord of Okayama
and established in 1870. Now with 1,300
faculty and 14,000 students, the University
offers courses in specialties ranging frommedicine and pharmacy to humanities
and physical sciences. Okayama
University is located in the heart of Japan
approximately 3 hours west of Tokyo byShinkansen.

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