Inhibition of neuropeptide Y Y1 receptor induces osteoblast differentiation in MC3T3-E1 cells

Abstract

Neuropeptide Y (NPY) is a major neural signaling molecule. NPY is produced by peripheral tissues, such as osteoblasts, and binds to the corresponding Y1 receptor that belongs to the G‑protein‑coupled receptor family. Osteoblast‑specific Y1 receptor knockout mice exhibit high bone mass, indicating a role of the NPY‑Y1 receptor axis in the regulation of bone homeostasis. In the bone microenvironment, peripheral nerve fibers and osteoblasts produce NPY. However, the effects of the Y1 receptor on osteoblasts remain unexplored. In the present study, an RNA interference approach was employed to target the Y1 receptor, in order to determine whether it may function to regulate the growth, differentiation and viability of osteoblasts. Knockdown of the Y1 receptor by small interfering RNA (siRNA) lead to induction of alkaline phosphatase (ALP) activity and mineralization in mouse MC3T3‑E1 osteoblast cells. In addition, the mRNA expression levels of ALP, osteocalcin, collagen (I) α1, and bone sialoprotein were significantly increased following transfection of a Y1 receptor siRNA. Furthermore, the mRNA expression levels of Runx2 and osterix were significantly increased; however, no significant alterations in cell proliferation and caspase‑3/7 activity were observed in Y1 receptor siRNA‑transfected cells when compared with non‑targeting controls. The results demonstrate that Y1 receptor inhibition may increase osteoblastic differentiation, which indicates a role of the Y1 receptor in the regulation of osteoblastic differentiation.

Inhibition of Y1 Receptor Promotes Osteogenesis in Bone Marrow Stromal Cells via cAMP/PKA/CREB Pathway

“…Given the critical role of RUNX2 and Osterix in osteogenic differentiation, we then scanned their expression levels in BMSCs. Y1 receptor deficiency significantly increased RUNX2 expression at the early stage of osteogenic differentiation, which was consistent with previous reports (7,37). In contrast, Y1 receptor deficiency enhanced Osterix expression at the relative late stage of osteogenic differentiation.…”

“…Furthermore, osteoblast specific knockout of Y1 receptor also enhances the differentiation potential of BMSCs and results in increased bone formation in mice, suggesting a critical role of Y1 receptor in osteoblast ( 7 ). Practically, RUNX2, a key transcription factor for osteogenesis, is upregulated by Y1 receptor silence in both the bones tissues ( 7 ) and MC3T3−E1 osteoblast cells ( 37 ). RUNX2 is critical for early-stage differentiation of BMSCs, which drives the expression of many osteoblast-specific genes ( 38 , 39 ).…”

Biomimetic intrafibrillar mineralized collagen promotes bone regeneration via activation of the Wnt signaling pathway

“…Although this gene expression may reflect different rates of nerve fiber regeneration within the defect, some studies of neuropeptide modulation of osteoblast differentiation indicate that neurogenesis-related genes may take an active role in enhancing bone regeneration. [21][22][23] The Wnt signaling pathway, which is well known to play an active role in the various stages of osteogenesis, 24,25 was the major pathway that was differentially regulated in this study. The full range of signaling factors, including ligands (Wnt5a), receptors (Fzd1, Fzd6, and Lrp5), cytoplasmic signal transduction molecules (Apc2, Dvl, and Pp3ca), nuclear transcription factors (Tcf3), transcription factors (Nfat5), and antagonists (Axin2 and Wif1) were differentially expressed.…”

Neuropeptide�Y upregulates Runx2 and osterix and enhances osteogenesis in mouse MC3T3‑E1 cells via an autocrine mechanism

“…However, in rodents, bone mass is regulated by the Y1 and Y2 receptors only (12). in previous studies, inhibiting the Y1 receptor increased the mrna expression levels of osterix and runt-related transcription factor 2 (runx2), two transcription factors essential for osteoblastic differentiation and bone formation (13). Y1 inhibition can also promote the activity of runx2 and osterix, and thus may contribute to osteoblastic differentiation and the expression of osteocalcin (ocn), alkaline phosphatase (alP), bone sialoprotein (BSP) and collagen 1α (14).…”