JAK2 Inhibition by Fedratinib Reduces Osteoblast Differentiation and Mineralisation of Human Mesenchymal Stem Cells

Abstract

Several signalling pathways, including the JAK/STAT signalling pathway, have been identified to regulate the differentiation of human bone marrow skeletal (mesenchymal) stem cells (hBMSCs) into bone-forming osteoblasts. Members of the JAK family mediate the intracellular signalling of various of cytokines and growth factors, leading to the regulation of cell proliferation and differentiation into bone-forming osteoblastic cells. Inhibition of JAK2 leads to decoupling of its downstream mediator, STAT3, and the subsequent inhibition of JAK/STAT signalling. However, the crucial role of JAK2 in hBMSCs biology has not been studied in detail. A JAK2 inhibitor, Fedratinib, was identified during a chemical biology screen of a small molecule library for effects on the osteoblastic differentiation of hMSC-TERT cells. Alkaline phosphatase activity and staining assays were conducted as indicators of osteoblastic differentiation, while Alizarin red staining was used as an indicator of in vitro mineralised matrix formation. Changes in gene expression were assessed using quantitative real-time polymerase chain reaction. Fedratinib exerted significant inhibitory effects on the osteoblastic differentiation of hMSC-TERT cells, as demonstrated by reduced ALP activity, in vitro mineralised matrix formation and downregulation of osteoblast-related gene expression, including ALP, ON, OC, RUNX2, OPN, and COL1A1. To identify the underlying molecular mechanisms, we examined the effects of Fedratinib on a molecular signature of several target genes known to affect hMSC-TERT differentiation into osteoblasts. Fedratinib inhibited the expression of LIF, SOCS3, RRAD, NOTCH3, TNF, COMP, THBS2, and IL6, which are associated with various signalling pathways, including TGFβ signalling, insulin signalling, focal adhesion, Notch Signalling, IL-6 signalling, endochondral ossification, TNF-α, and cytokines and inflammatory response. We identified a JAK2 inhibitor (Fedratinib) as a powerful inhibitor of the osteoblastic differentiation of hMSC-TERT cells, which may be useful as a therapeutic option for treating conditions associated with ectopic bone formation or osteosclerotic metastases.

Concentrated Growth Factors Promote hBMSCs Osteogenic Differentiation in a Co-Culture System With HUVECs

“…Our above-obtained results showed that CGF promotes hBMSCs osteogenic differentiation in a co-culture system, but the underlying mechanism is not clear. Various signaling pathways have been found to regulate the osteogenic differentiation of hBMSCs, including Notch signaling, Wnt/β-catenin, MAPK singaling,TGFβ, BMP-Smad singaling, Jak-STAT signaling, and Hedgehog signaling( AlMuraikhi et al, 2021 ; Pengjam et al, 2016 .). Therefore, we performed RNA-Seq and KEGG pathway analysis to further study the underlying mechanism.…”

Impact of Graphene Derivatives as Artificial Extracellular Matrices on Mesenchymal Stem Cells

“…They direct a variability of chemokines and cytokines which boost healing of degraded tissues and restoration of metabolism and inflammation. Usually, the emission of therapeutic factors enhances upon permission by inflammatory signals or apoptosis, which are encouraged by the host immune system [70].…”

Inhibition of GSK-3β Enhances Osteoblast Differentiation of Human Mesenchymal Stem Cells through Wnt Signalling Overexpressing Runx2

“…MSCs can self-renew and differentiate into different cell types, including bone osteoblast cells [ 15 , 16 ]. The osteoblastic differentiation of human MSCs comprises complicated processes controlled by various signaling pathways, including Wnt [ 17 , 18 ], Tankyrase [ 19 ], JAK-STAT signaling [ 20 , 21 ], Hedgehog signaling [ 22 ], TGFβ [ 23 ], BMP/Smad [ 24 ], PI3K/Akt/mTOR [ 25 ], and Notch signaling [ 26 ]. However, their relative involvement on osteoblastic differentiation must be further investigated.…”

“…However, their relative involvement on osteoblastic differentiation must be further investigated. Small-molecule inhibitors have been widely exploited as biochemical tools to help investigate the involvement of different signaling pathways in osteoblastic differentiation, which may reflect on therapeutic findings [ 19 , 20 , 21 , 22 , 26 ].…”