A Comparison of Osteoblast and Osteocyte Expression in Human Bone and Cultured Mesenchymal Stem Cells

Osteoporosis is an immense and growing health and economic burden of the aging population. Its prevalence in both men and women makes it an important target for biochemical research and development. A comparative study of the skeletal gene expression in native trabecular bone and cartilage tissues to marrow mesenchymal stem cells (MSCs) was carried out on tissues and cells obtained from acetabular reaming from total hip replacement patients (n=10). The intent of these comparisons was to examine the differentiation potential of MSCs grown from the bone marrow that was cultured for 21 days in three types of media: control media supplemented with fetal bovine serum with (CM) and without dexamethasone (CM-D), and an artificial (AFM) devoid of any animal product supplementation. RNA was extracted from these samples, and the bone and cartilage, and qRT-PCR was carried out to measure the expression of five genes of interest. The genes of interest (COL1A1, RUNX2, SP7, DMP1, and SOST) were chosen to respectively assess the progression of cellular and tissue differentiation from MSCs into osteocytes.

There were significant differences in gene expression of RUNX2, SP7, DMP1, and SOST between CM, AFM, and bone samples suggesting that each of the culture conditions promoted differing amounts of osteogenic differentiation. CM samples were relatively undifferentiated compared to the CM-D and AFM cultured cells, and likely contained little or no osteocytes but likely had some amount of osteoblasts. AFM cells appeared to be the most differentiated based on comparisons of their expression of mRNAs found in osteocytes. Bone and cartilage samples were also tested for the same genes of interest. AFM, CM, and CM-D had higher gene expression in markers for osteoblasts that are in the process of differentiating, while bone and cartilage showed a higher expression of the terminal osteocytic marker. Overall, this study showed that artificial media cultured MSCs differentiate at a faster rate than cells grown in the animal supplemented media.

Year	Entry
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Year

Entry

2017

Curtis EM, Moon RJ, Harvey NC, Cooper C. The impact of fragility fracture and approaches to osteoporosis risk assessment worldwide. Bone. November 2017;104:29-38.

2010

Raggatt LJ, Partridge NC. Cellular and molecular mechanisms of bone remodeling. J Biol Chem. August 13, 2010;285(33):25103-25108.

2012

Estrada K, Styrkarsdottir U, Evangelou E, Hsu Y-H, Duncan EL, Ntzani EE, Oei L, Albagha OME, Amin N, Kemp JP, Koller DL, Li G, Liu C-T, Minster RL, Moayyeri A, Vandenput L, Willner D, Xiao S-M, Yerges-Armstrong LM, Zheng H-F, Alonso N, Eriksson J, Kammerer CM, Kaptoge SK, Leo PJ, Thorleifsson G, Wilson SG, Wilson JF, Aalto V, Alen M, Aragaki AK, Aspelund T, Center JR, Dailiana Z, Duggan DJ, Garcia M, Garcia-Giralt N, Giroux S, Hallmans G, Hocking LJ, Husted LB, Jameson KA, Khusainova R, Kim GS, Kooperberg C, Koromila T, Kruk M, Laaksonen M, Lacroix AZ, Lee SH, Leung PC, Lewis JR, Masi L, Mencej-Bedrac S, Nguyen TV, Nogues X, Patel MS, Prezelj J, Rose LM, Scollen S, Siggeirsdottir K, Smith AV, Svensson O, Trompet S, Trummer O, van Schoor NM, Woo J, Zhu K, Balcells S, Brandi ML, Buckley BM, Cheng S, Christiansen C, Cooper C, Dedoussis G, Ford I, Frost M, Goltzman D, González-Macías J, Kähönen M, Karlsson M, Khusnutdinova E, Koh J-M, Kollia P, Langdahl BL, Leslie WD, Lips P, Ljunggren Ö, Lorenc RS, Marc J, Mellström D, Obermayer-Pietsch B, Olmos JM, Pettersson-Kymmer U, Reid DM, Riancho JA, Ridker PM, Rousseau F, Slagboom PE, Tang NLS, Urreizti R, Van Hul W, Viikari J, Zarrabeitia MT, Aulchenko YS, Castano-Betancourt M, Grundberg E, Herrera L, Ingvarsson T, Johannsdottir H, Kwan T, Li R, Luben R, Medina-Gómez C, Palsson ST, Reppe S, Rotter JI, Sigurdsson G, van Meurs JBJ, Verlaan D, Williams FMK, Wood AR, Zhou Y, Gautvik KM, Pastinen T, Raychaudhuri S, Cauley JA, Chasman DI, Clark GR, Cummings SR, Danoy P, Dennison EM, Eastell R, Eisman JA, Gudnason V, Hofman A, Jackson RD, Jones G, Jukema JW, Khaw K-T, Lehtimäki T, Liu Y, Lorentzon M, McCloskey E, Mitchell BD, Nandakumar K, Nicholson GC, Oostra BA, Peacock M, Pols HAP, Prince RL, Raitakari O, Reid IR, Robbins J, Sambrook PN, Sham PC, Shuldiner AR, Tylavsky FA, van Duijn CM, Wareham NJ, Cupples LA, Econs MJ, Evans DM, Harris TB, Kung AWC, Psaty BM, Reeve J, Spector TD, Streeten EA, Zillikens MC, Thorsteinsdottir U, Ohlsson C, Karasik D, Richards JB, Brown MA, Stefansson K, Uitterlinden AG, Ralston SH, Ioannidis JPA, Kiel DP, Rivadeneira F. Genome-wide meta-analysis identifies 56 bone mineral density loci and reveals 14 loci associated with risk of fracture. Nat Genet. April 15, 2012;44(5):491-501.

2016

Black DM, Rosen CJ. Postmenopausal osteoporosis. NEJM. January 21, 2016;374(3):254-262.

2017

Khosla S, Hofbauer LC. Osteoporosis treatment: recent developments and ongoing challenges. Lancet Diabetes Endocrinol. November 2017;5(11):898-907.