Dataset Information

The cytoskeletal regulatory scaffold protein GIT2 modulates mesenchymal stem cell differentiation and osteoblastogenesis.

ABSTRACT: G protein-coupled receptor kinase interacting protein 2 (GIT2) is a signaling scaffold protein involved in the regulation of cytoskeletal structure, membrane trafficking, and G protein-coupled receptor internalization. Since dynamic cytoskeletal reorganization plays key roles both in osteoblast differentiation and in the maintenance of osteoclast polarity during bone resorption, we hypothesized that skeletal physiology would be altered in GIT2(-/-) mice. We found that adult GIT2(-/-) mice have decreased bone mineral density and bone volume in both the trabecular and cortical compartments. This osteopenia was associated with decreased numbers of mature osteoblasts, diminished osteoblastic activity, and increased marrow adiposity, suggesting a defect in osteoblast maturation. In vitro, mesenchymal stem cells derived from GIT2(-/-) mice exhibited impaired differentiation into osteoblasts and increased adipocyte differentiation, consistent with a role for GIT2 in mesenchymal stem cell fate determination. Despite elevated osteoclast inducing cytokines and osteoclast numbers, GIT2(-/-) mice also exhibit impaired bone resorption, consistent with a further role for GIT2 in regulating osteoclast function. Collectively, these findings underscore the importance of the cytoskeleton in both osteoblast and osteoclast function and demonstrate that GIT2 plays essential roles in skeletal metabolism, affecting both bone formation and bone resorption in vivo.

SUBMITTER: Wang X

PROVIDER: S-EPMC3432571 | biostudies-literature | 2012 Aug

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

The cytoskeletal regulatory scaffold protein GIT2 modulates mesenchymal stem cell differentiation and osteoblastogenesis.

Wang Xiaojuan X Liao Shaoxi S Nelson Erik R ER Schmalzigaug Robert R Spurney Robert F RF Guilak Farshid F Premont Richard T RT Gesty-Palmer Diane D

Biochemical and biophysical research communications 20120727 2

G protein-coupled receptor kinase interacting protein 2 (GIT2) is a signaling scaffold protein involved in the regulation of cytoskeletal structure, membrane trafficking, and G protein-coupled receptor internalization. Since dynamic cytoskeletal reorganization plays key roles both in osteoblast differentiation and in the maintenance of osteoclast polarity during bone resorption, we hypothesized that skeletal physiology would be altered in GIT2(-/-) mice. We found that adult GIT2(-/-) mice have d ...[more]

PMID: 22846567

Similar Datasets

Project description:Unlabelled: Gene-modified mesenchymal stem cell (MSC)-like cells with enhanced bone marrow homing and osteogenesis have been used in treating glucocorticoid-induced murine osteoporosis (GIOP). Recent preclinical studies have further demonstrated the immunomodulatory and anticatabolic potential of allogeneic MSCs in treating osteoporosis under inflammatory and autoimmune conditions. In this study, we investigated whether systemic infusion of allogeneic MSCs without genetic manipulation could prevent GIOP, whether anabolic and anticatabolic effects existed, and whether homing or immunomodulation underlay the putative therapeutic effects. Allogeneic bone marrow-derived MSCs (BMMSCs) were isolated, identified, and systemically infused into mice treated with excessive dexamethasone. We revealed that allogeneic MSC transplantation prevented the reduction of bone mass and strength in GIOP. Bone histomorphometric analyses of bone remodeling demonstrated the maintenance of bone formation and osteoblast survival after MSC therapy. Using green fluorescent protein (GFP)-labeled BMMSCs, we showed that donor BMMSCs(GFP) homed and inhabited recipient bone marrow for at least 4 weeks and prevented recipient bone marrow cell apoptosis, as shown by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling. Furthermore, donor BMMSCs(GFP) committed to Osterix (Osx)(+) osteoblast progenitors and induced recipient osteoblastogenesis, as exhibited by GFP-Osx double-labeling immunofluorescence analysis. No anticatabolic effects or systemic immunomodulatory effects of infused BMMSCs were detected. These findings demonstrated that allogeneic MSC therapy prevented GIOP by inhabiting and functioning in recipient bone marrow, which promoted osteoblastogenesis, which in turn maintained bone formation. Our findings provide important information regarding cell-based anabolic therapy for GIOP and uncover MSC behaviors following the homing event.SignificanceThis study revealed the therapeutic potential of systemically infused, genetically unmodified allogeneic MSCs in glucocorticoid-induced osteoporosis. The donor MSCs inhabited recipient bone marrow and promoted osteoblastogenesis. The therapeutic effects were based on maintenance of bone formation. These results provide important information regarding cell-based anabolic therapy for glucocorticoid-induced osteoporosis and uncover previously unrecognized mesenchymal stem cell behaviors following a homing event. The current study also indicates that minimizing the time of cell culture confers an advantage for increasing transplanted mesenchymal stem cells to the targeted organ to promote therapeutic effects.

Project description:ObjectiveTo investigate the modulation of microRNAs (miRNAs) upon the neuronal differentiation of mesenchymal stem cells (MSCs) through targeting RE-1 Silencing Factor (REST), a mature neuronal gene suppressor in neuronal and un-neuronal cells.MethodsRat bone marrow derived-MSCs were induced into neuron-like cells (MSC-NCs) by DMSO and BHA in vitro. The expression of neuron specific enolase (NSE), microtubule-associated protein tau (Tau), REST and its target genes, including synaptosomal-associated protein 25 (SNAP25) and L1 cell adhesion molecular (L1CAM), were detected in MSCs and MSC-NCs. miRNA array analysis was conducted to screen for the upregulated miRNAs after neuronal differentiation. TargetScan was used to predict the relationship between these miRNAs and REST gene, and dual luciferase reporter assay was applied to validate it. Gain and loss of function experiments were used to study the role of miR-29a upon neuronal differentiation of MSCs. The knockdown of REST was conducted to show that miR-29a affected this process through targeting REST.ResultsMSCs were induced into neuron-like cells which presented neuronal cell shape and expressed NSE and Tau. The expression of REST declined and the expression of SNAP25 and L1CAM increased upon the neuronal differentiation of MSCs. Among 14 upregulated miRNAs, miR-29a was validated to target REST gene. During the neuronal differentiation of MSCs, miR-29a inhibition blocked the downregulation of REST, as well as the upregulation of SNAP25, L1CAM, NSE and Tau. REST knockdown rescued the effect of miR-29a inhibition on the expression of NSE and Tau. Meanwhile, miR-29a knockin significantly decreased the expression of REST and increased the expression of SNAP25 and L1CMA in MSCs, but did not significantly affect the expression of NSE and Tau.ConclusionmiR-29a regulates neurogenic markers through targeting REST in mesenchymal stem cells, which provides advances in neuronal differentiation research and stem cell therapy for neurodegenerative diseases.

Dataset Information

The cytoskeletal regulatory scaffold protein GIT2 modulates mesenchymal stem cell differentiation and osteoblastogenesis.

Publications

The cytoskeletal regulatory scaffold protein GIT2 modulates mesenchymal stem cell differentiation and osteoblastogenesis.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets