Cyclic Tensile Strain Enhances Osteogenesis and Angiogenesis in Mesenchymal Stem Cells from Osteoporotic Donors

We have shown that the uniaxial cyclic tensile strain of magnitude 10% promotes and enhances osteogenesis of human mesenchymal stem cells (hMSC) and human adipose-derived stem cells (hASC) from normal, nonosteoporotic donors. In the present study, MSC from osteoporotic donors were analyzed for changes in mRNA expression in response to 10% uniaxial tensile strain to identify potential mechanisms underlying the use of this mechanical loading paradigm for prevention and treatment of osteoporosis. Human MSC isolated from three female, postmenopausal osteoporotic donors were analyzed for their responses to mechanical loading using microarray analysis of over 47,000 gene probes. Human MSC were seeded in three-dimensional collagen type I constructs to mimic the organic extracellular matrix of bone and 10% uniaxial cyclic tensile strain was applied to promote osteogenesis. Seventy-nine genes were shown to be regulated within hMSC from osteoporotic donors in response to 10% cyclic tensile strain. Upregulation of six genes were further confirmed with real-time RT-PCR: jun D proto-oncogene (JUND) and plasminogen activator, urokinase receptor (PLAUR), two genes identified as potential key molecules from network analysis; phosphoinositide-3-kinase, catalytic, delta polypeptide (PIK3CD) and wingless-type MMTV integration site family, member 5B (WNT5B), two genes with known importance in bone biology; and, PDZ and LIM domain 4 (PDLIM4) and vascular endothelial growth factor A (VEGFA), two genes that we have previously shown are significantly regulated in hASC in response to this mechanical stimulus. Function analysis indicated that 10% cyclic tensile strain induced expression of genes associated with cell movement, cell proliferation, and tissue development, including development in musculoskeletal and cardiovascular systems. Our results demonstrate that hMSC from aged, osteoporotic donors are capable of enhanced osteogenic differentiation in response to 10% cyclic tensile strain with significant increases in the expression of genes associated with enhanced cell proliferation, musculoskeletal development, and angiogenesis. Surprisingly, cyclic tensile strain of magnitude 10% not only enhanced osteogenesis in hMSC from osteoporotic donors, but also enhanced expression of angiogenic factors. Better understanding and methodologies to promote osteogenesis in hMSC from elderly, osteoporotic donors may greatly facilitate achieving long-term success in bone regeneration and functional bone tissue engineering for this ever-growing patient population

A high concentration of genistein down-regulates activin A, Smad3 and other TGF-β pathway genes in human uterine leiomyoma cells

Previously, we found that high doses of genistein show an inhibitory effect on uterine leiomyoma (UtLM) cell proliferation. In this study, using microarray analysis and Ingenuity Pathways Analysis™, we identified genes (up- or down-regulated, ≥ 1.5 fold, P ≤ 0.001), functions and signaling pathways that were altered following treatment with an inhibitory concentration of genistein (50 µg/ml) in UtLM cells. Downregulation of TGF-β signaling pathway genes, activin A, activin B, Smad3, TGF-β2 and genes related to cell cycle regulation, with the exception of the upregulation of the CDK inhibitor P15, were identified and validated by real-time RT-PCR studies. Western blot analysis further demonstrated decreased protein expression of activin A and Smad3 in genistein-treated UtLM cells. Moreover, we found that activin A stimulated the growth of UtLM cells, and the inhibitory effect of genistein was partially abrogated in the presence of activin A. Overexpression of activin A and Smad3 were found in tissue samples of leiomyoma compared to matched myometrium, supporting the contribution of activin A and Smad3 in promoting the growth of UtLM cells. Taken together, these results suggest that down-regulation of activin A and Smad3, both members of the TGF-β pathway, may offer a mechanistic explanation for the inhibitory effect of a high-dose of genistein on UtLM cells, and might be potential therapeutic targets for treatment of clinical cases of uterine leiomyomas

Cyclic Tensile Strain Enhances Osteogenesis and Angiogenesis in Mesenchymal Stem Cells from Osteoporotic Donors

We have shown that the uniaxial cyclic tensile strain of magnitude 10% promotes and enhances osteogenesis of human mesenchymal stem cells (hMSC) and human adipose-derived stem cells (hASC) from normal, nonosteoporotic donors. In the present study, MSC from osteoporotic donors were analyzed for changes in mRNA expression in response to 10% uniaxial tensile strain to identify potential mechanisms underlying the use of this mechanical loading paradigm for prevention and treatment of osteoporosis. Human MSC isolated from three female, postmenopausal osteoporotic donors were analyzed for their responses to mechanical loading using microarray analysis of over 47,000 gene probes. Human MSC were seeded in three-dimensional collagen type I constructs to mimic the organic extracellular matrix of bone and 10% uniaxial cyclic tensile strain was applied to promote osteogenesis. Seventy-nine genes were shown to be regulated within hMSC from osteoporotic donors in response to 10% cyclic tensile strain. Upregulation of six genes were further confirmed with real-time RT-PCR: jun D proto-oncogene (JUND) and plasminogen activator, urokinase receptor (PLAUR), two genes identified as potential key molecules from network analysis; phosphoinositide-3-kinase, catalytic, delta polypeptide (PIK3CD) and wingless-type MMTV integration site family, member 5B (WNT5B), two genes with known importance in bone biology; and, PDZ and LIM domain 4 (PDLIM4) and vascular endothelial growth factor A (VEGFA), two genes that we have previously shown are significantly regulated in hASC in response to this mechanical stimulus. Function analysis indicated that 10% cyclic tensile strain induced expression of genes associated with cell movement, cell proliferation, and tissue development, including development in musculoskeletal and cardiovascular systems. Our results demonstrate that hMSC from aged, osteoporotic donors are capable of enhanced osteogenic differentiation in response to 10% cyclic tensile strain with significant increases in the expression of genes associated with enhanced cell proliferation, musculoskeletal development, and angiogenesis. Surprisingly, cyclic tensile strain of magnitude 10% not only enhanced osteogenesis in hMSC from osteoporotic donors, but also enhanced expression of angiogenic factors. Better understanding and methodologies to promote osteogenesis in hMSC from elderly, osteoporotic donors may greatly facilitate achieving long-term success in bone regeneration and functional bone tissue engineering for this ever-growing patient population

Double-Stranded RNA-Activated Protein Kinase Regulates Early Innate Immune Responses During Respiratory Syncytial Virus Infection

Respiratory syncytial virus (RSV) is the most common cause of childhood viral bronchiolitis and lung injury. Inflammatory responses significantly contribute to lung pathologies during RSV infections and bronchiolitis but the exact mechanisms have not been completely defined. The double-stranded RNA-activated protein kinase (PKR) functions to inhibit viral replication and participates in several signaling pathways associated with innate inflammatory immune responses. Using a functionally defective PKR (PKR?/?) mouse model, we investigated the role of this kinase in early events of RSV-induced inflammation. Our data showed that bronchoalveolar lavage (BAL) fluid from infected PKR?/? mice had significantly lower levels of several innate inflammatory cytokines and chemokines. Histological examinations revealed that there was less lung injury in infected PKR?/? mice as compared to the wild type. A genome-wide analysis showed that several early antiviral and immune regulatory genes were affected by PKR activation. These data suggest that PKR is a signaling molecule for immune responses during RSV infections.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/85133/1/jir_2009_0051.pd