Okayama University Research: Role of Commensal Microbiota in Bone Remodeling
OKAYAMA, Japan, December 26, 2018 /PRNewswire/ --
Researchers at Okayama University report in the journal Molecules that commensal microbiota - microorganisms present in the human body - may play a key role in human-bone remodeling by enhancing the activity of both cells breaking down bone tissue and cells synthesizing bone.
(Photo: https://mma.prnewswire.com/media/802369/Okayama_University.jpg )
Humans are host to several types of microorganisms like bacteria, fungi and viruses. Those residing in the human body without harming it are collectively called commensal microbiota. While it has been established that commensal microbiota play an important role in the body's energy management and the development of its immune system, recent findings have suggested that they affect the regulation of human bone formation too. Now, by performing comparative experiments on mice, Professor Manabu Morita, Yoko Uchida (D.D.S.) and colleagues from Okayama University confirmed the link between commensal microbiota and bone cell regulation. Specifically, they found that the presence of the microorganisms enhances the activity of both osteoclasts (cells that break down bone tissue) and osteoblasts (cells that synthesize bone).
Professor Morita and colleagues worked with two types of mouse: germ-free (GF) mice, free of any microorganisms, and specific-pathogen-free (SPF) mice, which are guaranteed to be free of certain pathogens but at the same time host to commensal microbiota.
The researchers investigated the activity of osteoclasts and osteoblasts in 8-week-old GF and SPF mice. They first looked at body weight and size. The SPF mice were found to have larger body size but lower bone mineral density in alveolar bones (the bones that contain the tooth sockets on the jaw bones), an observation attributed to the presence of commensal microbiota. In addition, by analyzing blood serum of the mice for substances that are associated with osteoclast activity, Professor Morita and colleagues were able to conclude that commensal microbiota cause greater development and activity of osteoclasts.
The scientists also discovered that the expression of osteocalcin messenger RNA- a maker of bone mineralization - is significantly higher in SPF mice, providing a further link between commensal microbiota and bone-remodeling processes.
While the precise mechanism of commensal microbiota affecting the expression of osteo-blast-specific genes such as osteocalcin needs to be further investigated in order to be completely understood, quoting Professor Morita and colleagues, "[these results] suggest that the commensal microbiota prevents excessive mineralization possibly by stimulating osteocalcin expression in osteoblasts, and enhances both osteoblast and osteoclast activity by regulating specific transcription factors."
Background
Commensal microbiota
The term microbiota refers to the collective of bacteria and other microorganisms in an animal's body. The term commensal is used when the presence of the microbiota is not harmful for the animal host. Professor Manabu Morita, Yoko Uchida (D.D.S.) and colleagues from Okayama University have now studied the influence of commensal microbiota on bone remodeling in mice. Their findings show that commensal microbiota have a regulatory effect on bone formation, as shown by differences in body weight and size between mice with and without commensal microbiota.
Osteocalcin. Bone density
Osteocalcin is a protein occurring in bone, produced by osteoblasts (bone-synthesizing cells). It is known to play a role in bone mineralization. As such, osteocalcin is often used as a biochemical marker for bone-formation activity. Professor Morita and colleagues were able to show that in specific-pathogen-free (SPF) mice, the expression of osteocalcin is related to the presence of commensal microbiota.
The study also involved measurements of bone density, or bone mineral density - the amount of bone mineral in bone tissue. While the SPF mice exhibited a larger body size, their bone density was found to be lower.
Reference
Yoko Uchida, Koichiro Irie, Daiki Fukuhara, Kota Kataoka, Takako Hattori, Mitsuaki Ono, Daisuke Ekuni, Satoshi Kubota, Manabu Morita. Commensal microbiota enhance both osteoclast and osteoblast activities. Molecules, 2018 Jun 23;23(7). pii: E1517. DOI: 10.3390/molecules23071517. https://www.mdpi.com/1420-3049/23/7/1517
Reference (Okayama University OU-MRU) : Professor Morita's team
OU-MRU Vol.59 Role of commensal flora in periodontal immune response investigated [https://www.okayama-u.ac.jp/eng/research_highlights/index_id76.html ]
Okayama University Medical Research Updates OU-MRU
The whole volume : OU-MRU (1- ) [https://www.okayama-u.ac.jp/eng/research/ou-mru.html ]
Vol.1 Innovative non-invasive 'liquid biopsy' method to capture circulating tumor cells from blood samples for genetic testing [http://www.okayama-u.ac.jp/eng/release/index_id210.html ]
Vol.2 Ensuring a cool recovery from cardiac arrest [http://www.okayama-u.ac.jp/eng/release/index_id248.html ]
Vol.3 Organ regeneration research leaps forward [https://www.okayama-u.ac.jp/eng/release/index_id252.html ]
Vol.4 Cardiac mechanosensitive integrator [http://www.okayama-u.ac.jp/eng/release/index_id261.html ]
Vol.5 Cell injections get to the heart of congenital defects [http://www.okayama-u.ac.jp/eng/release/index_id265.html ]
Vol.6 Fourth key molecule identified in bone development [http://www.okayama-u.ac.jp/eng/release/index_id266.html ]
Vol.7 Anticancer virus solution provides an alternative to surgery [http://www.okayama-u.ac.jp/eng/release/index_id273.html ]
Vol.8 Light-responsive dye stimulates sight in genetically blind patients [http://www.okayama-u.ac.jp/eng/release/index_id275.html ]
Vol.9 Diabetes drug helps towards immunity against cancer [http://www.okayama-u.ac.jp/eng/release/index_id282.html ]
Vol.10 Enzyme-inhibitors treat drug-resistant epilepsy [http://www.okayama-u.ac.jp/eng/release/index_id294.html ]
Vol.11 Compound-protein combination shows promise for arthritis treatment [http://www.okayama-u.ac.jp/eng/release/index_id304.html ]
Vol.12 Molecular features of the circadian clock system in fruit flies [http://www.okayama-u.ac.jp/eng/release/index_id315.html ]
Vol.13 Peptide directs artificial tissue growth [http://www.okayama-u.ac.jp/eng/release/index_id324.html ]
Vol.14 Simplified boron compound may treat brain tumours [http://www.okayama-u.ac.jp/eng/release/index_id328.html ]
Vol.15 Metamaterial absorbers for infrared inspection technologies [http://www.okayama-u.ac.jp/eng/research_highlights/index_id10.html ]
Vol.16 Epigenetics research traces how crickets restore lost limbs [http://www.okayama-u.ac.jp/eng/research_highlights/index_id12.html ]
Vol.17 Cell research shows pathway for suppressing hepatitis B virus [http://www.okayama-u.ac.jp/eng/research_highlights/index_id13.html ]
Vol.18 Therapeutic protein targets liver disease [http://www.okayama-u.ac.jp/eng/research_highlights/index_id15.html ]
Vol.19 Study links signalling protein to osteoarthritis [http://www.okayama-u.ac.jp/eng/research_highlights/index_id17.html ]
Vol.20 Lack of enzyme promotes fatty liver disease in thin patients [http://www.okayama-u.ac.jp/eng/research_highlights/index_id18.html ]
Vol.21 Combined gene transduction and light therapy targets gastric cancer [http://www.okayama-u.ac.jp/eng/research_highlights/index_id19.html ]
Vol.22 Medical supportive device for hemodialysis catheter puncture [http://www.okayama-u.ac.jp/eng/research_highlights/index_id20.html ]
Vol.23 Development of low cost oral inactivated vaccines for dysentery [http://www.okayama-u.ac.jp/eng/research_highlights/index_id25.html ]
Vol.24 Sticky molecules to tackle obesity and diabetes [http://www.okayama-u.ac.jp/eng/research_highlights/index_id26.html ]
Vol.25 Self-administered aroma foot massage may reduce symptoms of anxiety [http://www.okayama-u.ac.jp/eng/research_highlights/index_id31.html ]
Vol.26 Protein for preventing heart failure [http://www.okayama-u.ac.jp/eng/research_highlights/index_id37.html ]
Vol.27 Keeping cells in shape to fight sepsis [http://www.okayama-u.ac.jp/eng/research_highlights/index_id38.html ]
Vol.28 Viral-based therapy for bone cancer [http://www.okayama-u.ac.jp/eng/research_highlights/index_id39.html ]
Vol.29 Photoreactive compound allows protein synthesis control with light [http://www.okayama-u.ac.jp/eng/research_highlights/index_id40.html ]
Vol.30 Cancer stem cells' role in tumor growth revealed [http://www.okayama-u.ac.jp/eng/research_highlights/index_id41.html ]
Vol.31 Prevention of RNA virus replication [http://www.okayama-u.ac.jp/eng/research_highlights/index_id42.html ]
Vol.32 Enzyme target for slowing bladder cancer invasion [http://www.okayama-u.ac.jp/eng/research_highlights/index_id43.html ]
Vol.33 Attacking tumors from the inside [http://www.okayama-u.ac.jp/eng/research_highlights/index_id44.html ]
Vol.34 Novel mouse model for studying pancreatic cancer [http://www.okayama-u.ac.jp/eng/research_highlights/index_id45.html ]
Vol.35 Potential cause of Lafora disease revealed [http://www.okayama-u.ac.jp/eng/research_highlights/index_id46.html ]
Vol.36 Overloading of protein localization triggers cellular defects [http://www.okayama-u.ac.jp/eng/research_highlights/index_id47.html ]
Vol.37 Protein dosage compensation mechanism unravelled [https://www.okayama-u.ac.jp/eng/research_highlights/index_id48.html ]
Vol.38 Bioengineered tooth restoration in a large mammal [http://www.okayama-u.ac.jp/eng/research_highlights/index_id49.html ]
Vol.39 Successful test of retinal prosthesis implanted in rats [http://www.okayama-u.ac.jp/eng/research_highlights/index_id54.html ]
Vol.40 Antibodies prolong seizure latency in epileptic mice [http://www.okayama-u.ac.jp/eng/research_highlights/index_id55.html ]
Vol.41 Inorganic biomaterials for soft-tissue adhesion [http://www.okayama-u.ac.jp/eng/research_highlights/index_id56.html ]
Vol.42 Potential drug for treating chronic pain with few side effects [http://www.okayama-u.ac.jp/eng/research_highlights/index_id57.html ]
Vol.43 Potential origin of cancer-associated cells revealed [http://www.okayama-u.ac.jp/eng/research_highlights/index_id59.html ]
Vol.44 Protection from plant extracts [http://www.okayama-u.ac.jp/eng/research_highlights/index_id60.html ]
Vol.45 Link between biological-clock disturbance and brain dysfunction uncovered [http://www.okayama-u.ac.jp/eng/research_highlights/index_id61.html ]
Vol.46 New method for suppressing lung cancer oncogene [http://www.okayama-u.ac.jp/eng/research_highlights/index_id62.html ]
Vol.47 Candidate genes for eye misalignment identified [http://www.okayama-u.ac.jp/eng/research_highlights/index_id64.html ]
Vol.48 Nanotechnology-based approach to cancer virotherapy [http://www.okayama-u.ac.jp/eng/research_highlights/index_id65.html ]
Vol.49 Cell membrane as material for bone formation [http://www.okayama-u.ac.jp/eng/research_highlights/index_id66.html ]
Vol.50 Iron removal as a potential cancer therapy [http://www.okayama-u.ac.jp/eng/research_highlights/index_id67.html ]
Vol.51 Potential of 3D nanoenvironments for experimental cancer [http://www.okayama-u.ac.jp/eng/research_highlights/index_id68.html ]
Vol.52 A protein found on the surface of cells plays an integral role in tumor growth and sustenance [http://www.okayama-u.ac.jp/eng/research_highlights/index_id69.html ]
Vol.53 Successful implantation and testing of retinal prosthesis in monkey eyes with retinal degeneration [http://www.okayama-u.ac.jp/eng/research_highlights/index_id70.html ]
Vol.54 Measuring ion concentration in solutions for clinical and environmental research [http://www.okayama-u.ac.jp/eng/research_highlights/index_id71.html ]
Vol.55 Diabetic kidney disease: new biomarkers improve the prediction of the renal prognosis [http://www.okayama-u.ac.jp/eng/research_highlights/index_id72.html ]
Vol.56 New device for assisting accurate hemodialysis catheter placement [http://www.okayama-u.ac.jp/eng/research_highlights/index_id73.html ]
Vol.57 Possible link between excess chewing muscle activity and dental disease [https://www.okayama-u.ac.jp/eng/research_highlights/index_id74.html ]
Vol.58 Insights into mechanisms governing the resistance to the anti-cancer medication cetuximab [https://www.okayama-u.ac.jp/eng/research_highlights/index_id75.html ]
Vol.59 Role of commensal flora in periodontal immune response investigated [https://www.okayama-u.ac.jp/eng/research_highlights/index_id76.html ]
About Okayama University
Okayama University is one of the largest comprehensive universities in Japan with roots going back to the Medical Training Place sponsored by the Lord of Okayama and established in 1870. Now with 1,300 faculty and 13,000 students, the University offers courses in specialties ranging from medicine and pharmacy to humanities and physical sciences. Okayama University is located in the heart of Japan approximately 3 hours west of Tokyo by Shinkansen.
Website: http://www.okayama-u.ac.jp/index_e.html
Correspondence to
Professor Manabu Morita, D.D.S., Ph.D. Department of Preventive Dentistry, OkayamaUniversity Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan. E-mail: mmorita@md.okayama-u.ac.jp
Further information
Okayama University 1-1-1 Tsushima-naka , Kita-ku , Okayama 700-8530, Japan
Public Relations and Information Strategy E-mail: www-adm@adm.okayama-u.ac.jp Website: http://www.okayama-u.ac.jp/index_e.html Okayama Univ. e-Bulletin: http://www.okayama-u.ac.jp/user/kouhou/ebulletin
About Okayama University (YouTube): https://www.youtube.com/watch?v=iDL1coqPRYI
Okayama University Image Movie (YouTube): https://www.youtube.com/watch?v=KU3hOIXS5kk
Photo:
https://mma.prnewswire.com/media/802369/Okayama_University.jpg
SOURCE Okayama University
