Effect of GARP on osteogenic differentiation of bone marrow mesenchymal stem cells via the regulation of TGFβ1 in vitro

Abstract

Mesenchymal stem cells (MSCs), which have multipotential differentiation and self-renewal potential, are possible cells for tissue engineering. Transforming growth factor β1 (TGFβ1) can be produced by MSCs in an inactive form, and the activation of TGFβ1 functions as an important regulator of osteogenic differentiation in MSCs. Recently, studies showed that Glycoprotein A repetitions predominant (GARP) participated in the activation of latent TGFβ1, but the interaction between GARP and TGFβ1 is still undefined. In our study, we successfully isolated the MSCs from bone marrow of rats, and showed that GARP was detected in bone mesenchymal stem cells (BMSCs). During the osteogenic differentiation of BMSCs, GARP expression was increased over time. To elucidate the interaction between GARP and TGFβ1, we downregulated GARP expression in BMSCs to examine the level of active TGFβ1. We then verified that the downregulation of GARP decreased the secretion of active TGFβ1. Furthermore, osteogenic differentiation experiments, alkaline phosphatase (ALP) activity analyses and Alizarin Red S staining experiments were performed to evaluate the osteogenic capacity. After the downregulation of GARP, ALP activity and Alizarin Red S staining significantly declined and the osteogenic indicators, ALP, Runx2, and OPN, also decreased, both at the mRNA and protein levels. These results demonstrated that downregulated GARP expression resulted in the reduction of TGFβ1 and the attenuation of osteoblast differentiation of BMSCs in vitro.

GARP promotes the proliferation and therapeutic resistance of bone sarcoma cancer cells through the activation of TGF-β

“…One representative experiment out of two is shown. immunomodulation 26,34 . However, whether GARP is expressed by mesenchymal neoplasms and its effect on chemo/radiation-induced cell death are unknown.…”

GARP is a key molecule for mesenchymal stromal cell responses to TGF-β and fundamental to control mitochondrial ROS levels

“…In this sense, GARP‐overexpressing MSCs could be advantageous for the treatment of inflammatory/autoimmune diseases as the GARP/TGF‐β axis promotes immune tolerance, in part, through the induction of Tregs . However, GARP/TGF‐β was recently shown to promote the osteogenic differentiation of MSCs in vitro . Thus, GARP ++ MSCs could be ideal for bone regeneration applications while giving rise to unwanted differentiation when used in inflammatory/autoimmune diseases.…”

Bioinformatics analysis and identification of circular RNAs promoting the osteogenic differentiation of human bone marrow mesenchymal stem cells on titanium treated by surface mechanical attrition

“…Its activity level is positively correlated with the degree of osteogenic differentiation of cells. It is an early marker of osteogenic differentiation of hBMSCs ( Samuel et al, 2016 ; Li et al, 2019 ). The sample was reacted in a carbonate buffer (pH = 9.8) containing p-nitrobenzene phosphate.…”

“…It can recognize and chelate calcium ions to form orange-red calcium nodules. It is a sign of late osteogenic differentiation ( Li et al, 2019 ). The area of alizarin red staining of cells on both groups of materials gradually increased with the increase of culture time.…”

“…In the comparison of the two groups of materials, QRT-PCR results showed that the differential expression of hsa_circ_0032600 on the 14th day was significant ( p -values), which is consistent with the results of alizarin red staining. The combination mRNAs of hsa_circ_0032600 including wnt3, wnt4, CBFB, IGF1, CHRD involved in Wnt, Smad2/3, MAPK/ERK, TGF-β osteogenic pathways, which can regulate osteogenic differentiation in the middle and late stages ( Mobini et al, 2017 ; Li et al, 2019 ; Mao, Bian & Shen, 2012 ). So hsa_circ_0032600 can regulate the osteogenic differentiation of hBMSCs on the middle and late stages.…”