Research was partly supported by NIH research grants R01 AR062173 and SHC 250862 to IEA. ES is the recipient of NIH T32 CTSC predoctoral fellowship.

1. Hydrodynamic Delivery of sRANKL MC DNA
<ol>
	<li>Hydrodynamic Delivery via Mouse Tail Vein
	<ol>
		<li>Weigh the mouse before the tail vein injection. Dilute sRANKL or green fluorescent protein (GFP) MC in Ringer's solution (pre-warm at 37 &#176;C) in a total volume of ~10% of the mouse's body weight.</li>
		<li>Warm up the mouse in a cage for 10 min prior to injection in order to dilate blood vessels and make lateral veins (LVs) visible. Monitor the mouse carefully to avoid dehydration and hyperthermia.</li>
		<li>...

<ol>
	<li>Yelin, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cost+of+musculoskeletal+diseases:+impact+of+work+disability+and+functional+decline.">Cost of musculoskeletal diseases: impact of work disability and functional decline.</a> The Journal of rheumatology. Supplement. 68, 8-11 (2003).</li><li>Boyce, B. F., Rosenberg, E., de Papp, A. E., Duong le, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+osteoclast,+bone+remodelling+and+treatment+of+metabolic+bone+disease.">The osteoclast, bone remodelling and treatment of metabolic bone disease.</a> European journal of clinical investigation. 42, 1332-1341 (2012).</li><li>Lacey, D. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Osteoprotegerin+ligand+is+a+cytokine+that+regulates+osteoclast+differentiation+and+activation.">Osteoprotegerin ligand is a cytokine that regulates osteoclast differentiation and activation.</a> Cell. 93, 165-176 (1998).</li><li>Mizuno, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transgenic+mice+overexpressing+soluble+osteoclast+differentiation+factor+(sODF)+exhibit+severe+osteoporosis.">Transgenic mice overexpressing soluble osteoclast differentiation factor (sODF) exhibit severe osteoporosis.</a> Journal of bone and mineral metabolism. 20, 337-344 (2002).</li><li>Bucay, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=osteoprotegerin-deficient+mice+develop+early+onset+osteoporosis+and+arterial+calcification.">osteoprotegerin-deficient mice develop early onset osteoporosis and arterial calcification.</a> Gene., &amp; development. 12, 1260-1268 (1998).</li><li>Suda, T., Liu, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrodynamic+gene+delivery:+its+principles+and+applications.">Hydrodynamic gene delivery: its principles and applications.</a> Molecular therapy: the journal of the American Society of Gene Therapy. 15, 2063-2069 (2007).</li><li>Wronski, T. 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S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=RANKL+inhibition+with+osteoprotegerin+increases+bone+strength+by+improving+cortical+and+trabecular+bone+architecture+in+ovariectomized+rats.">RANKL inhibition with osteoprotegerin increases bone strength by improving cortical and trabecular bone architecture in ovariectomized rats.</a> Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research. 23, 672-682 (2008).</li><li>Kitazawa, R., Kimble, R. B., Vannice, J. L., Kung, V. 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Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+robust+system+for+production+of+minicircle+DNA+vectors.">A robust system for production of minicircle DNA vectors.</a> Nature biotechnology. 28, 1287-1289 (2010).</li><li>Chen, Z. Y., He, C. Y., Kay, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improved+production+and+purification+of+minicircle+DNA+vector+free+of+plasmid+bacterial+sequences+and+capable+of+persistent+transgene+expression+in+vivo.">Improved production and purification of minicircle DNA vector free of plasmid bacterial sequences and capable of persistent transgene expression in vivo.</a> Human gene therapy. 16, 126-131 (2005).</li><li>Halleen, J. 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The authors have nothing to disclose.

Musculoskeletal conditions are leading causes of morbidity and disability and are comprised of over 150 diseases and syndromes; affecting approximately 90 million Americans today. Joint inflammation and bone destruction are predominant features of musculoskeletal conditions, including arthritis and osteoporosis. Osteoporosis is a condition that weakens bone integrity, often leading to fractures of the bone. Arthritis is a chronic, debilitating disease characterized by inflammation of the joints that become swollen, tende...

Musculoskeletal diseases affect millions of people in the United States and present severe consequences for national and local health systems1. These disorders are characterized by loss of bone and joint function that require extensive treatment and long periods of recovery. Commonly, a relative increase in the number and/or activity of osteoclasts, cells specialized to resorb bone, in osteoporosis and arthritis is observed2. Under physiological conditions the number and activity of osteoclasts is regulated by receptor activator of nuclear factor &#954;-B ligand (RANKL), which is produced by osteoblasts. Osteoprotegerin (OPG), a decoy receptor for RANKL is also produced by osteoblasts3. In vivo animal models that involve systemic overexpression of sRANKL, or deletion of OPG are very valuable in osteoporosis research; however, these methods require the generation of transgenic mice4,5. Here, a novel alternative method of overexpressing sRANKL for the study of musculoskeletal-related disorders is described. Specifically, minicircle (MC) DNA technology and hydrodynamic delivery methods were used to achieve gene transfer of sRANKL in vivo and overexpress mouse sRANKL systemically6.
This method is also complementary to other in vivo models of osteoporosis, such as hormonal modulation of osteoclasts following ovariectomy7 and dietary intervention by low-calcium diet8. These models are very useful to study different aspects of musculoskeletal-related disorders however they require surgical procedures and may take up to several months, at a significant cost9. Ovariectomized (OVX) rodent model is an experimental animal model where removal of ovaries leads to estrogen deficiency thereby mimicking human postmenopausal osteoporosis10. Human post-menopausal osteoporosis, a condition where estrogen deficiency leads to increased risk of bone fractures and osteoporosis affects approximately eight million women in the United States alone. Although the OVX model is useful for post-menopausal osteoporosis it offers limited advantages in studying osteoporosis in general. Estrogen suppresses bone loss, by inducing osteoclast and inhibiting osteoblast apoptosis, therefore in its absence an increased osteoclast activity is observed10-12. A RANKL-OPG ratio imbalance that favors bone resorption is also observed13. However, estrogen deficiency in vivo is also accompanied by decreased levels of transforming growth factor &#946; (TGF &#946;), increased interleukin-7 (IL-7) and TNF, IL-1 and IL-614,15. As these cytokines have known bone remodeling modulatory functions independent of the RANKL pathway, it is impossible to attribute any osteoclast activation solely to the RANKL-RANK axis. The model described in this paper enables researchers to study in vivo RANKL-RANK axis in osteoclastogenesis and bone loss without pro-inflammatory cytokines compared to OVX rodent models.
Additionally, in vitro osteoclastogenesis techniques are essential tools to study osteoclast activation for potential therapeutic treatments of musculoskeletal diseases. Previous studies have also shown that culturing mouse bone marrow derived macrophages (BMMs) with mouse macrophage colony-stimulating factor (M-CSF) and mouse sRANKL can lead to osteoclast differentiation3,16,17. Here, the protocols to generate multinucleated osteoclast-like cells from mouse bone marrow as well as from human peripheral blood mononuclear cells (PBMCs) in vitro18 are described. The cell-based assays required to define a mature terminally differentiated and fully functional osteoclast are also briefly described. These in vitro techniques complement the novel in vivo approach and together serve as powerful investigative tools to study osteoclast differentiation and activation. Using these systems, scientists are able to generate osteoclasts in vivo and in vitro and define the stimuli and signals required for their proliferation and activation as well as test the efficacy of pharmacological and biological inhibitors.

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	<tbody>
		<tr height="63">
			<td height="63" style="height:63px;width:320px;">alpha-MEM</td>
			<td style="width:71px;">Life Technologies&#160;</td>
			<td style="width:119px;">12561-056</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:320px;">Human M-CSF</td>
			<td style="width:71px;">Miltenyi Biotec</td>
			<td style="width:119px;">130-096-492</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:320px;">Mouse M-CSF</td>
			<td style="width:71px;">Miltenyi Biotec</td>
			<td style="width:119px;">130-094-643</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:320px;">Human RANK-Ligand - soluble</td>
			<td style="width:71px;">Miltenyi Biotec</td>
			<td>130-094-631</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:320px;">Mouse RANK-Ligand - soluble</td>
			<td style="width:71px;">Miltenyi Biotec</td>
			<td style="width:119px;">130-094-076</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:320px;">Tailveiner Restrainer for mice</td>
			<td style="width:71px;">Braintree</td>
			<td style="width:119px;">TV-150 STD</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">Mouse TRANCE/RANK L/TNFSF11 Quantikine ELISA Kit&#160;</td>
			<td style="width:71px;">R&#38;D systems</td>
			<td style="width:119px;">MTR00</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Acid Phosphatase, Leukocyte (TRAP) Kit</td>
			<td style="width:71px;">Sigma</td>
			<td style="width:119px;">387A</td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:320px;">MouseTRAP assay&#160;</td>
			<td style="width:71px;">immunodiagnostic systems</td>
			<td style="width:119px;">SB-TR103</td>
			<td></td>
		</tr>
	</tbody>
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a novel in vivo gene transfer technique and in vitro cell based assays for the study of bone loss in musculoskeletal disorders

Differentiation and activation of osteoclasts play a key role in the development of musculoskeletal diseases as these cells are primarily involved in bone resorption. Osteoclasts can be generated in vitro from monocyte/macrophage precursor cells in the presence of certain cytokines, which promote survival and differentiation. Here, both in vivo and in vitro techniques are demonstrated, which allow scientists to study different cytokine contributions towards osteoclast differentiation, signaling, and activation. The minicircle DNA delivery gene transfer system provides an alternative method to establish an osteoporosis-related model is particularly useful to study the efficacy of various pharmacological inhibitors in vivo. Similarly, in vitro culturing protocols for producing osteoclasts from human precursor cells in the presence of specific cytokines enables scientists to study osteoclastogenesis in human cells for translational applications. Combined, these techniques have the potential to accelerate drug discovery efforts for osteoclast-specific targeted therapeutics, which may benefit millions of osteoporosis and arthritis patients worldwide.

Here, a novel gene transfer technique for differentiation of osteoclasts in vivo and cell culture protocols for differentiating precursor cells into osteoclasts in vitro as a method to study the effects of cytokines on osteoclastogenesis are described. In Figure 1, the representative results of successful gene transfer of GFP and mouse sRANKL MC in mice are shown. In Figure 2, the representative images of mouse bone marrow or human PBMC cell differentiation time course ...

Watch this Scientific Journal Video about A Novel in vivo Gene Transfer Technique and in vitro Cell Based Assays for the Study of Bone Loss in Musculoskeletal Disorders at JoVE.com

A Novel in vivo Gene Transfer Technique and in vitro Cell Based Assays for the Study of Bone Loss in Musculoskeletal Disorders

Differentiation of precursor cells into osteoclasts is regulated by cytokines and growth factors. Here, a novel gene transfer technique for differentiation of osteoclasts in vivo and cell culture protocols for differentiating precursor cells into osteoclasts in vitro as a method to study the effects of cytokines on osteoclastogenesis are described.

A Novel in vivo Gene Transfer Technique and in vitro Cell Based Assays for the Study of Bone Loss in Musculoskeletal Disorders

Differentiation and activation of osteoclasts play a key role in the development of musculoskeletal diseases as these cells are primarily involved in bone ...

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11.6K Görüntüleme.  University of California, Davis. Differentiation of precursor cells into osteoclasts is regulated by cytokines and growth factors. Here, a novel gene transfer technique for differentiation of osteoclasts in vivo and cell culture protocols for differentiating precursor cells into osteoclasts in vitro as a method to study the effects of cytokines on osteoclastogenesis are described. 