Mechanical strain modulates age-related changes in the proliferation and differentiation of mouse adipose-derived stromal cells
© Huang et al; licensee BioMed Central Ltd. 2010
Received: 13 July 2009
Accepted: 10 March 2010
Published: 10 March 2010
Previous studies on the effects of aging in human and mouse mesenchymal stem cells suggest that a decline in the number and differentiation potential of stem cells may contribute to aging and aging-related diseases. In this report, we used stromal cells isolated from adipose tissue (ADSCs) of young (8-10 weeks), adult (5 months), and old (21 months) mice to test the hypothesis that mechanical loading modifies aging-related changes in the self-renewal and osteogenic and adipogenic differentiation potential of these cells.
We show that aging significantly reduced the proliferation and increased the adipogenesis of ADSCs, while the osteogenic potential is not significantly reduced by aging. Mechanical loading (10% cyclic stretching, 0.5 Hz, 48 h) increased the subsequent proliferation of ADSCs from mice of all ages. Although the number of osteogenic colonies with calcium deposition was increased in ADSCs subjected to pre-strain, it resulted from an increase in colony number rather than from an increase in osteogenic potential after strain. Pre-strain significantly reduced the number of oil droplets and the expression of adipogenic marker genes in adult and old ADSCs. Simultaneously subjecting ADSCs to mechanical loading and adipogenic induction resulted in a stronger inhibition of adipogenesis than that caused by pre-strain. The reduction of adipogenesis by mechanical strain was loading-magnitude dependent: loading with 2% strain only resulted in a partial inhibition, and loading with 0.5% strain could not inhibit adipogenesis in ADSCs.
We demonstrate that mechanical stretching counteracts the loss of self-renewal in aging ADSCs by enhancing their proliferation and, at the same time, reduces the heightened adipogenesis of old cells. These findings are important for the further study of stem cell control and treatment for a variety of aging related diseases.
Recent findings on age-related changes in adult stem cells and stem cell niches suggest that the aging process and aging-related diseases may involve age-dependent stem cell loss, including alterations in their numbers and/or differentiation potential, although many of the details are still not understood . One example of aging-related diseases is osteoporosis in the elderly, in which bone loss and increased bone marrow fat may result from reduced osteogenic potential and a tilted osteogenic/adipogenic balance in bone marrow mesenchymal stem cells (BMMSCs) [2, 3]. Another example is obesity, which can be a risk factor for diabetes and cardiovascular diseases and involves excess accumulation of white adipose tissue that is differentiated from MSCs . Most of the current knowledge regarding adult stem cells derives from studies of MSCs isolated from bone marrow. Displaying similar differentiating potentials to BMMSCs, ADSCs possess clear advantage in clinical uses due to easy and repeatable access as well as simple isolation and expansion procedures that promise broad applications for cell therapy and tissue engineering [5, 6]. Age-related declines in the lifespan, proliferation, and differentiation capacity of human and mouse BMMSCs have been reported previously [7–12], but most of the mechanisms are still unclear. Aging effects in human and murine ADSCs were only partially explored, and it appears that the osteogenic differentiation capacity of ADSCs is maintained with aging [5, 13].
Effects of mechanical force on growth rate, signal transduction, and cell phenotype have been widely documented in a variety of cell types. Mechanical loading was reported to induce osteogenic differentiation [14–17] and smooth muscle cell differentiation [18–20] in BMMSCs, or lead to inhibition of adipogenesis  through durable β-catenin activation . In growing mice, exposure to low-magnitude mechanical signals alters the cell fate of BMMSCs by inhibiting adipogenesis . Uniaxial strain inhibited the proliferation of human ADSCs and the expression of early smooth muscle cell markers . In this study, we looked for aging-related differences in ADSCs isolated from young, adult, and old mice. By applying mechanical strain, we tested the hypothesis that mechanical loading counteracts the effects of aging by modulating the self-renewal and differentiation potential of murine ADSCs.
Age-related changes in mouse ADSCs
To test the differentiation potential of ADSCs, P1 cells were subjected to osteo-, myo-, and adipogenic induction for 21 days followed by von Kossa, Liu's, or Oil-Red O staining (Figure 1C). Compared to young ADSCs, old ADSCs exhibited reduced von Kossa staining and formed fewer multinucleated myotubes, indicating a reduction in calcium deposition and myogenic differentiation. The Oil-Red O staining of old ADSCs was significantly stronger than young ADSCs, indicating that the adipogenic potential was elevated by aging.
Mechanical loading counteracts aging-dependent changes
Pre-exposure to mechanical strain increases ADSC self-renewal
Pre-exposure to mechanical strain increases calcium deposition, but not osteogenic potential in ADSC colonies
Pre-exposure to mechanical strain inhibits adipogenic differentiation in aging ADSCs
Aging related changes in ADSCs and response to mechanical loading.
Stronger inhibition of adipogenesis by simultaneous mechanical loading and differentiation induction
The purpose of this study is to investigate the behavioral change of ADSCs in various degrees of aging with respect to self-renewal and differentiation induced by chemical cues. Another focus of this study is to explore improvement of the declined functions in aged ADSCs by mechanical loading. That ADSCs responded to 10% strain was previously reported [23, 24], therefore, we used 10% strain in most experiments as the starting loading magnitude. We demonstrated that the result of mechanical loading in ADSCs depends on magnitude of the applied strain in which high strain (2-10%) significantly reduces adipogenesis and low strain (0.5%) has no effect (Figure 9). It should be noted that ADSCs in the mouse gonadal fat pad are not likely to experience 10% stretching in vivo, however, this magnitude of stretching is within the physiological range of loading for MSCs in muscular and peri-vascular tissues. We conducted our current study in ADSCs to take advantage of the ease of isolating large quantities of these cells from adult and aged animals. Further studies will be in need to verify that the observed results can be extrapolated to MSCs from other tissues as well as to the study of other forms of mechanical loading, using strain of various magnitudes, frequency, loading patterns, and durations.
Most current studies on MSCs have used established clones in which MSCs were selected through at least several rounds of passage and expansion. Aging (senescence) of MSCs in in vitro culture and loss of differentiation potential after the sixth passage has been demonstrated previously . In this study, we chose to study primary ADSCs culture in very early passages (P0-P3) in order to explore functional differences in ADSCs of various ages in the absence of artifacts likely contributed by clonal selection and expansion in long-term cultures. SVF from adipose tissue is known to contain primary cells with high degree of heterogeneity. We found that more than 50% of P0 cells after in vitro culture for one week exhibited the CD34-/CD45-/CD105+/CD73+/CD90+ surface markers, which are the most accepted surface markers for MSCs (data not shown). It should also be noted that > 95% of P6 young ADSCs were CD105+, CD73+, and CD90+ (data not shown). We failed to obtain ADSC colonies beyond P10 from 21-month-old mice (data not shown), indicating that passage-related senescence increases rapidly in old ADSC culture.
Short-term mechanical loading that simultaneously activates many mitotic signaling pathways is a strong inducer for cell proliferation . But, long-term mechanical loading (more than 24 h), which has not been as extensively studied as short-term loading, is less mitogenic [23, 27]. We purposely investigated the cellular responses to long-term stretching (48 h) to distinguish the responses as the true adaptation of cells to mechanical loading from transient reactions to sudden changes in mechanical environment. Immediately following mechanical stretching, instead of an increase, a slight decrease (less than 5%) in the number of ADSCs was found (data not shown). Thus, it is possible, also as a limitation for similar membrane stretching systems that mechanical stretching selects for cells that firmly adhere to the elastic membrane and allows the detached cells to die of anoikis. As a result, firmly adhered cells would be enriched following mechanical loading. Because the cell loss after strain was not significant when compared to the whole population, we believe that anoikis does not play an important role in our result. Yet, cell adhesion to substrate is an inherent cellular property that may be associated with self-renewal and differentiation potential. Indeed, BMMSCs of various sizes and different morphologies have been shown to exhibit different adhesion property to substrate . In a separate report, these heterogeneous cells also display different self-renewal abilities and express distinct surface markers . In addition, the role of adhesion to substrate in dictating MSC differentiation potential was recently demonstrated . Therefore, a change in ADSC adhesiveness to the substrate following mechanical loading should be investigated further. The finding that 48 h of pre-strain results in increased ADSC proliferation after replating (Figure 3) is intriguing to us. We did not find significant changes in the surface marker expression in ADSCs after applying strain (data not shown), therefore, the increase in proliferation following strain was not likely due to a selection for CD105+/CD73+/CD90+ cells during mechanical loading.
Because of a clear increase of calcium deposition in pre-strained ADSCs as well as in young cells, we originally hypothesized that aging would reduce, and mechanical stretching would enhance the osteogenesis capacity of ADSCs. An increase in calcium deposition can result from an increase in the number of total colonies without increasing the percentage of contained osteoblast colonies, or from an increase in both total colony number and the ratio of contained osteogenic colonies. While the former only results from an increase in proliferation, the latter represents a true increase in osteogenic capacity. By using adult ADSCs as a model, we demonstrated that in pre-strained cells, calcium deposition, when normalized to the DNA content, was not increased by strain as compared to non-strained cells. This result corroborates with the real time PCR data, which showed that bone marker gene expression did not increase as a result of pre-strain. The conclusion that the osteogenic potential of ADSC colonies was not increased by pre-strain is analogous to the result that no loss of osteogenic potential occurred in old ADSCs. Our finding in murine ADSCs is in agreement with previous reports that the osteogenic potential of human ADSCs from old donors was not reduced [13, 31]. In the literature, conflicting reports on the relative osteogenic potential of BMMSCs and ADSCs exist, and more findings indicate that ADSCs have an inferior osteogenic potential relative to BMMSCs [32–34]. Thus, it is also possible that we failed to detect changes in osteogenic potential due to aging or mechanical loading in ADSCs, while mechanical loading induces osteogenesis in BMMSCs in other reports, may result from the intrinsically lower osteogenic capacity of ADSCs.
The adipogenic program is regulated by multiple signaling pathways and involves the activation of numerous transcription factors. PPARγ serves as the pivotal transcription factor in adipogenesis. Several previous reports demonstrating that mechanical stretching inhibits PPARγ signaling in 3T3-L1 cells , BMMSCs  and skeletal myoblasts  may provide insight into the mechanism that underlies inhibition of adipogenesis by mechanical loading. We also found that a change in AP2 expression, previously considered a late marker of adipocytes, precedes the change in PPARγ expression induced in ADSCs by both aging and mechanical loading (10% strain). This result suggests that changes in PPARγ gene expression may not adequately reflect changes in PPARγ signaling, which can be better measured by the expression of its target genes. Indeed, AP2 is a PPARγ target gene [37, 38]. We are currently examining the molecular basis of the inhibition of PPARγ signaling and reduction in adipogenesis as a result of mechanical strain. Two mechanical loading methods, pre-strain (PS) and simultaneous adipogenic induction and strain (AS), were compared in this study. It is not surprising to observe a stronger inhibitory effect of AS on adipogenesis, considering that the mechanical loading activates known signaling pathways leading to adipogenesis inhibition. We have found activation of non-canonical Wnt signaling by mechanical strain, involving calcium/calmodulin-dependent kinase II and nemo-like kinase, in various precursor cell lines and primary cells . Therefore, inhibition of adipogenesis as a result of mechanical loading may be mediated by both canonical (β-catenin dependent)  and non-canonical Wnt pathways.
Our results demonstrate an aging-dependent loss of self-renewal and increased propensity for adipogenesis in old ADSCs and a positive effect of mechanical loading that counteracts the aging factor. These findings are important for the further study on stem cell mechanobiology and reveal the benefits and potential of combining an ex vivo mechanical loading regime with autologous ADSC transplantation in treatment for a variety of aging related diseases.
Chemicals and culture medium
All chemicals used in this study were purchased from Sigma-Aldrich unless otherwise specified. All culture medium and reagents were purchased from Gibco-Invitrogen unless otherwise specified.
Animals and ADSC isolation
All animal experiments were conducted in accordance with accepted standards of animal care and were approved by the Institutional Animal Care and Use Committee of the National Health Research Institutes in Taiwan. Male FVB/NarL mice were used in this study and were grouped into young (8-10 weeks), adult (5 months), and old (21 months) groups. After euthanization by CO2, gonadal fat pads were isolated and digested by following a published protocol with minor modifications . In short, fat pieces were digested with 0.2% collagenase for 30 min at 37°C, followed by two, 5 min centrifugations at 260 × g to remove the adipocytes in supernatant. Following RBC lysis with 0.83% NH4Cl, the cells were washed twice with PBS, resuspended in maintenance medium, and plated in culture dishes for 4 h to remove non-adherent cells. The attached cells were considered SVF of P0 ADSCs. The isolated SVF was used immediately for experiments or cryopreserved for future studies. SVFs were cultured in maintenance medium consisting of αMEM supplemented with 10% fetal bovine serum and 1% penicillin-streptomycin at 37°C in a humidified with 5% CO2, and the medium was changed every 72 h.
Application of mechanical strain
A Flexcell 4000T tensile system (Flexcell INT) with a 25 mm post was used to generate equibiaxial strain. 2.5 × 105 P2 ADSCs were plated in each well of a type 1 collagen-coated, flexible bottom plate (Flexwell) at 2.8 × 104 cells/cm2 and cultured for another 16 h, followed by a change to fresh medium before loading to the strain system. The mechanical stretching was applied as sinusoidal wave of 0.5 Hz for 48 h with a peak strain of 0.5%, 2%, or 10% as indicated in the text. The medium in the plate of non-strain controls was also changed and placed in the same incubator as the strain samples. At the end of mechanical loading, ADSCs were collected by trypsin/EDTA, counted, and replated in 6-well plates for colony forming and differentiation assays. In studies with simultaneous mechanical strain and differentiation induction, cells were incubated with osteogenic or adipogenic medium at the beginning of the mechanical loading as described above, followed by a change to fresh differentiation medium at the end of loading and continued incubation as indicated in the text with medium changed every 72 h.
Doubling time measurement and colony-forming assay
To measure the doubling time and colony-forming ability of ADSCs, 5000 cells were initially plated in each well of 6-well plates and cultured for various periods using maintenance medium. A cluster of cells consisting of at least five cells was considered a colony. The number of small (5-10 cells), medium (10-50 cells), and large (>50 cells) colonies formed by ADSCs in each well was counted.
Osteogenic induction and Alizarin Red S or von Kossa staining
Osteogenic differentiation was induced using a previously described method . In short, 2.5 × 104 ADSCs were seeded into each well of a 6-well plate, cultured for five days with maintenance medium, and then changed to differentiation induction medium. Osteogenic differentiation was induced by treating ADSCs with induction medium consisting of 100 nM dexamethasone, 10 mM sodium β-glycerophosphate, 0.05 mM L-ascorbic acid-2-phosphate (Fluka), and 10% fetal calf serum (FCS) in αMEM twice a week for 5, 14, and 21 days. For un-induced controls, cells were kept in maintenance medium. The degree of osteogenic differentiation was assessed by von Kossa or Alizarin Red S (ARS) staining for Ca2+ deposition using previously described protocols [42, 43]. After washing with calcium and phosphate-free saline, 70% ethanol-fixed cells were stained for 3 min with a 2% ARS solution (pH 4.2) at room temperature followed by washing with water and incubation with PBS for 15 min. To quantify the ARS staining result, the deposition was extracted by 10% (w/v) cetylpyridinium chloride in 10 mM sodium phosphate (pH 7.0) at room temperature for 1 h, and the ARS concentration in the extraction buffer was determined by measuring the absorbance at 562 nm. The absorbance values were normalized to the intensity of the ethidium bromide staining, which provides an estimation of the total DNA content of cells in a culture well. A standard curve correlating the intensity of ethidium bromide staining to the cell number in the well was established in parallel to correct for the factor used in normalization.
Myogenic induction and Liu's stain
Myogenic differentiation was induced using a previously described protocol . In short, sub-confluent cells were induced by 10 μM 5-azacytidine for 21 days. Myogenic differentiation was examined with Liu's stain for the appearance of multinucleated myotubes.
Adipogenic induction and Oil-Red O stain
Adipogenic differentiation was induced as previously described  using induction medium consisting of 10 μM dexamethasone, 0.25 μM 3-isobutyl-1-methyl-xanthine, 4 μM recombinant human insulin, 10 μM troglitazone, and 10% FCS. Adipogenic differentiation was assayed by the formation of neutral lipid vacuoles stainable with Oil-Red O.
Quantitative PCR for the measurement of osteogenic and adipogenic marker gene expression
Following osteogenic or adipogenic induction, ADSCs were lysed with Trizol to isolate RNA, followed by cDNA synthesis. Quantitative gene expression analysis was performed for mouse Runx2 and Bglap1 (Osteocalcin, OC) and normalized to GAPDH expression using Taqman gene expression assay (ABI system). The expression of adipogenic AP2 (Fabp4) and PPARγ was measured by Sybr Green-based real-time PCR, and the expression of β-actin was used as a control for constitutive expression. The sequences of probes and primers are listed in additional file 1.
All experiments were performed at least in triplicate. The results shown are the mean values with error bars representing the SEM. The two-tailed, unpaired Student's t-test was used for analysis unless otherwise specified. A P-value < 0.05 was considered significant.
This work was supported by Taiwan NHRI [ME097-PP02], [NM097-PP06], [ME097-SP07] to KML; Taiwan National Science Council [NSC-96-2627-B-400-001] to KML; and ITRI [7356EA5100] to SCH.
- Drummond-Barbosa D: Stem cells, their niches and the systemic environment: an aging network. Genetics. 2008, 180 (4): 1787-1797. 10.1534/genetics.108.098244.PubMed CentralView ArticlePubMedGoogle Scholar
- Di Iorgi N, Rosol M, Mittelman SD, Gilsanz V: Reciprocal relation between marrow adiposity and the amount of bone in the axial and appendicular skeleton of young adults. J Clin Endocrinol Metab. 2008, 93 (6): 2281-2286. 10.1210/jc.2007-2691.PubMed CentralView ArticlePubMedGoogle Scholar
- Meunier P, Courpron P, Edouard C, Bernard J, Bringuier J, Vignon G: Physiological senile involution and pathological rarefaction of bone. Quantitative and comparative histological data. Clin Endocrinol Metab. 1973, 2 (2): 239-256. 10.1016/S0300-595X(73)80042-8.View ArticlePubMedGoogle Scholar
- Park KW, Halperin DS, Tontonoz P: Before they were fat: adipocyte progenitors. Cell Metab. 2008, 8 (6): 454-457. 10.1016/j.cmet.2008.11.001.View ArticlePubMedGoogle Scholar
- Khan WS, Adesida AB, Tew SR, Andrew JG, Hardingham TE: The epitope characterisation and the osteogenic differentiation potential of human fat pad-derived stem cells is maintained with ageing in later life. Injury. 2009, 40 (2): 150-157. 10.1016/j.injury.2008.05.029.View ArticlePubMedGoogle Scholar
- Schaffler A, Buchler C: Concise review: adipose tissue-derived stromal cells--basic and clinical implications for novel cell-based therapies. Stem Cells. 2007, 25 (4): 818-827. 10.1634/stemcells.2006-0589.View ArticlePubMedGoogle Scholar
- Zhou S, Greenberger JS, Epperly MW, Goff JP, Adler C, Leboff MS, Glowacki J: Age-related intrinsic changes in human bone-marrow-derived mesenchymal stem cells and their differentiation to osteoblasts. Aging Cell. 2008, 7 (3): 335-343. 10.1111/j.1474-9726.2008.00377.x.PubMed CentralView ArticlePubMedGoogle Scholar
- Bergman RJ, Gazit D, Kahn AJ, Gruber H, McDougall S, Hahn TJ: Age-related changes in osteogenic stem cells in mice. J Bone Miner Res. 1996, 11 (5): 568-577. 10.1002/jbmr.5650110504.View ArticlePubMedGoogle Scholar
- D'Ippolito G, Schiller PC, Ricordi C, Roos BA, Howard GA: Age-related osteogenic potential of mesenchymal stromal stem cells from human vertebral bone marrow. J Bone Miner Res. 1999, 14 (7): 1115-1122. 10.1359/jbmr.19220.127.116.115.View ArticlePubMedGoogle Scholar
- Zheng H, Martin JA, Duwayri Y, Falcon G, Buckwalter JA: Impact of aging on rat bone marrow-derived stem cell chondrogenesis. J Gerontol A Biol Sci Med Sci. 2007, 62 (2): 136-148.View ArticlePubMedGoogle Scholar
- Roobrouck VD, Ulloa-Montoya F, Verfaillie CM: Self-renewal and differentiation capacity of young and aged stem cells. Exp Cell Res. 2008, 314 (9): 1937-1944. 10.1016/j.yexcr.2008.03.006.View ArticlePubMedGoogle Scholar
- Moerman EJ, Teng K, Lipschitz DA, Lecka-Czernik B: Aging activates adipogenic and suppresses osteogenic programs in mesenchymal marrow stroma/stem cells: the role of PPAR-gamma2 transcription factor and TGF-beta/BMP signaling pathways. Aging Cell. 2004, 3 (6): 379-389. 10.1111/j.1474-9728.2004.00127.x.PubMed CentralView ArticlePubMedGoogle Scholar
- Shi YY, Nacamuli RP, Salim A, Longaker MT: The osteogenic potential of adipose-derived mesenchymal cells is maintained with aging. Plast Reconstr Surg. 2005, 116 (6): 1686-1696. 10.1097/01.prs.0000185606.03222.a9.View ArticlePubMedGoogle Scholar
- David V, Martin A, Lafage-Proust MH, Malaval L, Peyroche S, Jones DB, Vico L, Guignandon A: Mechanical loading down-regulates peroxisome proliferator-activated receptor gamma in bone marrow stromal cells and favors osteoblastogenesis at the expense of adipogenesis. Endocrinology. 2007, 148 (5): 2553-2562. 10.1210/en.2006-1704.View ArticlePubMedGoogle Scholar
- Byrne EM, Farrell E, McMahon LA, Haugh MG, O'Brien FJ, Campbell VA, Prendergast PJ, O'Connell BC: Gene expression by marrow stromal cells in a porous collagen-glycosaminoglycan scaffold is affected by pore size and mechanical stimulation. J Mater Sci Mater Med. 2008, 19 (11): 3455-3463. 10.1007/s10856-008-3506-2.View ArticlePubMedGoogle Scholar
- Qi MC, Hu J, Zou SJ, Chen HQ, Zhou HX, Han LC: Mechanical strain induces osteogenic differentiation: Cbfa1 and Ets-1 expression in stretched rat mesenchymal stem cells. Int J Oral Maxillofac Surg. 2008, 37 (5): 453-458. 10.1016/j.ijom.2007.12.008.View ArticlePubMedGoogle Scholar
- Wiesmann A, Buhring HJ, Mentrup C, Wiesmann HP: Decreased CD90 expression in human mesenchymal stem cells by applying mechanical stimulation. Head Face Med. 2006, 2: 8-10.1186/1746-160X-2-8.PubMed CentralView ArticlePubMedGoogle Scholar
- Park JS, Chu JS, Cheng C, Chen F, Chen D, Li S: Differential effects of equiaxial and uniaxial strain on mesenchymal stem cells. Biotechnol Bioeng. 2004, 88 (3): 359-368. 10.1002/bit.20250.View ArticlePubMedGoogle Scholar
- Kurpinski K, Park J, Thakar RG, Li S: Regulation of vascular smooth muscle cells and mesenchymal stem cells by mechanical strain. Mol Cell Biomech. 2006, 3 (1): 21-34.PubMedGoogle Scholar
- Kurpinski K, Chu J, Hashi C, Li S: Anisotropic mechanosensing by mesenchymal stem cells. Proc Natl Acad Sci USA. 2006, 103 (44): 16095-16100. 10.1073/pnas.0604182103.PubMed CentralView ArticlePubMedGoogle Scholar
- Sen B, Xie Z, Case N, Ma M, Rubin C, Rubin J: Mechanical strain inhibits adipogenesis in mesenchymal stem cells by stimulating a durable beta-catenin signal. Endocrinology. 2008, 149 (12): 6065-6075. 10.1210/en.2008-0687.PubMed CentralView ArticlePubMedGoogle Scholar
- Rubin CT, Capilla E, Luu YK, Busa B, Crawford H, Nolan DJ, Mittal V, Rosen CJ, Pessin JE, Judex S: Adipogenesis is inhibited by brief, daily exposure to high-frequency, extremely low-magnitude mechanical signals. Proc Natl Acad Sci USA. 2007, 104 (45): 17879-17884. 10.1073/pnas.0708467104.PubMed CentralView ArticlePubMedGoogle Scholar
- Lee WC, Maul TM, Vorp DA, Rubin JP, Marra KG: Effects of uniaxial cyclic strain on adipose-derived stem cell morphology, proliferation, and differentiation. Biomech Model Mechanobiol. 2007, 6 (4): 265-273. 10.1007/s10237-006-0053-y.View ArticlePubMedGoogle Scholar
- Wall ME, Rachlin A, Otey CA, Loboa EG: Human adipose-derived adult stem cells upregulate palladin during osteogenesis and in response to cyclic tensile strain. Am J Physiol Cell Physiol. 2007, 293 (5): C1532-1538. 10.1152/ajpcell.00065.2007.View ArticlePubMedGoogle Scholar
- Bonab MM, Alimoghaddam K, Talebian F, Ghaffari SH, Ghavamzadeh A, Nikbin B: Aging of mesenchymal stem cell in vitro. BMC Cell Biol. 2006, 7: 14-10.1186/1471-2121-7-14.PubMed CentralView ArticlePubMedGoogle Scholar
- Chien S: Mechanotransduction and endothelial cell homeostasis: the wisdom of the cell. Am J Physiol Heart Circ Physiol. 2007, 292 (3): H1209-1224. 10.1152/ajpheart.01047.2006.View ArticlePubMedGoogle Scholar
- Lin K, Hsu PP, Chen BP, Yuan S, Usami S, Shyy JY, Li YS, Chien S: Molecular mechanism of endothelial growth arrest by laminar shear stress. Proc Natl Acad Sci USA. 2000, 97 (17): 9385-9389. 10.1073/pnas.170282597.PubMed CentralView ArticlePubMedGoogle Scholar
- Docheva D, Padula D, Popov C, Mutschler W, Clausen-Schaumann H, Schieker M: Researching into the cellular shape, volume and elasticity of mesenchymal stem cells, osteoblasts and osteosarcoma cells by atomic force microscopy. J Cell Mol Med. 2008, 12 (2): 537-552. 10.1111/j.1582-4934.2007.00138.x.PubMed CentralView ArticlePubMedGoogle Scholar
- Haasters F, Prall WC, Anz D, Bourquin C, Pautke C, Endres S, Mutschler W, Docheva D, Schieker M: Morphological and immunocytochemical characteristics indicate the yield of early progenitors and represent a quality control for human mesenchymal stem cell culturing. J Anat. 2009, 214 (5): 759-767. 10.1111/j.1469-7580.2009.01065.x.PubMed CentralView ArticlePubMedGoogle Scholar
- Oh S, Brammer KS, Li YS, Teng D, Engler AJ, Chien S, Jin S: Stem cell fate dictated solely by altered nanotube dimension. Proc Natl Acad Sci USA. 2009, 106 (7): 2130-2135. 10.1073/pnas.0813200106.PubMed CentralView ArticlePubMedGoogle Scholar
- Khan WS, Adesida AB, Tew SR, Andrew JG, Hardingham TE: The epitope characterisation and the osteogenic differentiation potential of human fat pad-derived stem cells is maintained with ageing in later life. Injury. 2009, 40 (2): 150-157. 10.1016/j.injury.2008.05.029.View ArticlePubMedGoogle Scholar
- Hayashi O, Katsube Y, Hirose M, Ohgushi H, Ito H: Comparison of osteogenic ability of rat mesenchymal stem cells from bone marrow, periosteum, and adipose tissue. Calcif Tissue Int. 2008, 82 (3): 238-247. 10.1007/s00223-008-9112-y.View ArticlePubMedGoogle Scholar
- De Ugarte DA, Morizono K, Elbarbary A, Alfonso Z, Zuk PA, Zhu M, Dragoo JL, Ashjian P, Thomas B, Benhaim P: Comparison of multi-lineage cells from human adipose tissue and bone marrow. Cells Tissues Organs. 2003, 174 (3): 101-109. 10.1159/000071150.View ArticlePubMedGoogle Scholar
- Im GI, Shin YW, Lee KB: Do adipose tissue-derived mesenchymal stem cells have the same osteogenic and chondrogenic potential as bone marrow-derived cells?. Osteoarthritis Cartilage. 2005, 13 (10): 845-853. 10.1016/j.joca.2005.05.005.View ArticlePubMedGoogle Scholar
- Tanabe Y, Nakayama K: [Mechanical stretching inhibits adipocyte differentiation of 3T3-L1 cells: the molecular mechanism and pharmacological regulation]. Nippon Yakurigaku Zasshi. 2004, 124 (5): 337-344.View ArticlePubMedGoogle Scholar
- Akimoto T, Ushida T, Miyaki S, Akaogi H, Tsuchiya K, Yan Z, Williams RS, Tateishi T: Mechanical stretch inhibits myoblast-to-adipocyte differentiation through Wnt signaling. Biochem Biophys Res Commun. 2005, 329 (1): 381-385. 10.1016/j.bbrc.2005.01.136.View ArticlePubMedGoogle Scholar
- Rival Y, Stennevin A, Puech L, Rouquette A, Cathala C, Lestienne F, Dupont-Passelaigue E, Patoiseau JF, Wurch T, Junquero D: Human adipocyte fatty acid-binding protein (aP2) gene promoter-driven reporter assay discriminates nonlipogenic peroxisome proliferator-activated receptor gamma ligands. J Pharmacol Exp Ther. 2004, 311 (2): 467-475. 10.1124/jpet.104.068254.View ArticlePubMedGoogle Scholar
- Yoshida K, Ono M, Koishi R, Furukawa H: Characterization of the 5' regulatory region of the mouse angiopoietin-like protein 4. Vet Res Commun. 2004, 28 (4): 299-305. 10.1023/B:VERC.0000026673.92065.c0.View ArticlePubMedGoogle Scholar
- Yu HC, Wu TC, Chen MR, Liu SW, Chen JH, Lin K: Mechanical stretching induces osteoprotegerin in differentiating C2C12 precursor cells through non-canonical Wnt pathways. J Bone Miner Res.Google Scholar
- Yamamoto N, Akamatsu H, Hasegawa S, Yamada T, Nakata S, Ohkuma M, Miyachi E, Marunouchi T, Matsunaga K: Isolation of multipotent stem cells from mouse adipose tissue. J Dermatol Sci. 2007, 48 (1): 43-52. 10.1016/j.jdermsci.2007.05.015.View ArticlePubMedGoogle Scholar
- Jaiswal N, Haynesworth SE, Caplan AI, Bruder SP: Osteogenic differentiation of purified, culture-expanded human mesenchymal stem cells in vitro. J Cell Biochem. 1997, 64 (2): 295-312. 10.1002/(SICI)1097-4644(199702)64:2<295::AID-JCB12>3.0.CO;2-I.View ArticlePubMedGoogle Scholar
- Stanford CM, Jacobson PA, Eanes ED, Lembke LA, Midura RJ: Rapidly forming apatitic mineral in an osteoblastic cell line (UMR 106-01 BSP). J Biol Chem. 1995, 270 (16): 9420-9428. 10.1074/jbc.270.16.9420.View ArticlePubMedGoogle Scholar
- Zhang W, Yang N, Shi XM: Regulation of mesenchymal stem cell osteogenic differentiation by glucocorticoid-induced leucine zipper (GILZ). J Biol Chem. 2008, 283 (8): 4723-4729. 10.1074/jbc.M704147200.View ArticlePubMedGoogle Scholar
- Roura S, Farre J, Soler-Botija C, Llach A, Hove-Madsen L, Cairo JJ, Godia F, Cinca J, Bayes-Genis A: Effect of aging on the pluripotential capacity of human CD105+ mesenchymal stem cells. Eur J Heart Fail. 2006, 8 (6): 555-563. 10.1016/j.ejheart.2005.11.006.View ArticlePubMedGoogle Scholar
- Kim YK, Choi HY, Kim NH, Lee W, Seo DW, Kang DW, Lee HY, Han JW, Park SW, Kim SN: Reversine stimulates adipocyte differentiation and downregulates Akt and p70(s6k) signaling pathways in 3T3-L1 cells. Biochem Biophys Res Commun. 2007, 358 (2): 553-558. 10.1016/j.bbrc.2007.04.165.View ArticlePubMedGoogle Scholar
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