scholarly journals Inhibition of miR-29-3p isoforms via tough decoy suppresses osteoblast function in homeostasis but promotes intermittent parathyroid hormone-induced bone anabolism

Bone ◽  
2021 ◽  
Vol 143 ◽  
pp. 115779
Author(s):  
Henry C. Hrdlicka ◽  
Renata C. Pereira ◽  
Bongjin Shin ◽  
Siu-Pok Yee ◽  
Alix C. Deymier ◽  
...  
Keyword(s):  
Parathyroid Hormone ◽  
Osteoblast Function

scholarly journals The Rho GTPase RAC1 in Osteoblasts Controls Their Function

2020 ◽  
Vol 21 (2) ◽  
pp. 385
Author(s):  
Katrin Huck ◽  
Carla Sens ◽  
Carina Wuerfel ◽  
Caren Zoeller ◽  
Inaam A. Nakchbandi
Keyword(s):  
Bone Mineral Density ◽  
Parathyroid Hormone ◽  
Signaling Pathways ◽  
Bone Mineral ◽  
Osteoblast Differentiation ◽  
Rho Gtpase ◽  
Mineral Density ◽  
Osteoblast Function

The regulation of the differentiation of the bone-forming cells, the osteoblasts, is complex. Many signaling pathways converge on the master regulator of osteoblast differentiation Runx2. The role of molecules that integrate several signaling pathways such as the Rho GTPases need to be better understood. We, therefore, asked at which stage Rac1, one of the Rho GTPase, is needed for osteoblast differentiation and whether it is involved in two pathways, the anabolic response to parathyroid hormone and the stimulatory effect of fibronectin isoforms on integrins. Genetic deletion of Rac1 in preosteoblasts using the osterix promoter diminished osteoblast differentiation in vitro. This effect was however similar to the presence of the promoter by itself. We, therefore, applied a Rac1 inhibitor and confirmed a decrease in differentiation. In vivo, Rac1 deletion using the osterix promoter decreased bone mineral density as well as histomorphometric measures of osteoblast function. In contrast, deleting Rac1 in differentiating osteoblasts using the collagen α1(I) promoter had no effects. We then evaluated whether intermittent parathyroid hormone (PTH) was able to affect bone mineral density in the absence of Rac1 in preosteoblasts. The increase in bone mineral density was similar in control animals and in mice in which Rac1 was deleted using the osterix promoter. Furthermore, stimulation of integrin by integrin isoforms was able to enhance osteoblast differentiation, despite the deletion of Rac1. In summary, Rac1 in preosteoblasts is required for normal osteoblast function and bone density, but it is neither needed for PTH-mediated anabolic effects nor for integrin-mediated enhancement of differentiation.

Abstract #191 Hallucinations and Paranoia in the Setting of an Intrathyroid Parathyroid Hormone Secreting Nodule

2019 ◽  
Vol 25 ◽  
pp. 56-57
Author(s):  
Robert Gaffey ◽  
Eric Pagan ◽  
Briette Karanfillian ◽  
Sahil Parikh ◽  
Ankit Shah
Keyword(s):  
Parathyroid Hormone

Abstract #615: Hypocalcemia Secondary to Parathyroid Hormone Resistance

2016 ◽  
Vol 22 ◽  
pp. 135
Author(s):  
Mitali Talsania ◽  
Ammara Aziz ◽  
Lauren LaBryer ◽  
Jonea Lim
Keyword(s):  
Parathyroid Hormone ◽  
Hormone Resistance
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