scholarly journals Polycytosine RNA-Binding Protein 1 Regulates Osteoblast Function via a Ferroptosis Pathway in Type 2 Diabetic Osteoporosis

Author(s):  
Hongdong Ma ◽  
yueming Jiang ◽  
Haitian Li ◽  
Maowei Yang

Abstract In recent years, type 2 diabetic osteoporosis has become a research hotspot for the complications of diabetes, but the specific mechanism of its occurrence and development remain unknown. Ferroptosis caused by iron overload is considered to be one of the important cause of type 2 diabetic osteoporosis. Polycytosine RNA-binding protein 1 (PCBP1), an iron ion chaperone, was considered as a protector of ferroptosis. The present study aimed to investigate the existence of ferroptosis and specific role of PCBP1 in the development of type 2 diabetes. Firstly, a Cell Counting Kit-8 assay was used to detect the changes of osteoblast viability under the influence of high glucose (HG) and/or ferroptosis inhibitor given at different concentrations and at different times. In addition, the morphological changes of mitochondria in osteoblasts under high glucose were examined via transmission electron microscopy, and the expression levels of PCBP1, ferritin and the ferroptosis-related protein glutathione peroxidase 4 (GPX4) under the action of high glucose were detected via western blotting. Furthermore, a lentivirus was used to silence and overexpress PCBP1. Western blotting was used to detect the expression of levels of the osteoblast functional proteins osteoprotegerin (OPG) and osteocalcin (OCN), while flow cytometry was used to detect the changes of reactive oxygen species (ROS) levels in each group. Under the action of high glucose, the viability of osteoblasts was significantly decreased and the number of mitochondria undergoing atrophy was significantly increased, PCBP1 and ferritin expression levels were increased and GPX4 expression was decreased. Western blotting results demonstrated that infection of the lentivirus overexpressing PCBP1, increased the expression levels of ferritin, GPX4, OPG and OCN, compared with the high glucose group. The flow cytometry results identified a reduction in ROS, and an opposite result was obtained after silencing PCBP1. In conclusion, it was suggested that PCBP1 may protect osteoblasts and reduce the harm caused by ferroptosis by promoting ferritin expression under a high glucose environment. Moreover, it was indicated that PCBP1 may be a potential therapeutic target for treating type 2 diabetic osteoporosis.

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Hongdong Ma ◽  
Xindong Wang ◽  
Weilin Zhang ◽  
Haitian Li ◽  
Wei Zhao ◽  
...  

Ferroptosis is recently identified, an iron- and reactive oxygen species- (ROS-) dependent form of regulated cell death. This study was designed to determine the existence of ferroptosis in the pathogenesis of type 2 diabetic osteoporosis and confirm that melatonin can inhibit the ferroptosis of osteoblasts through activating Nrf2/HO-1 signaling pathway to improve bone microstructure in vivo and in vitro. We treated MC3T3-E1 cells with different concentrations of melatonin (1, 10, or 100 μM) and exposed them to high glucose (25.5 mM) for 48 h in vitro. Our data showed that high glucose can induce osteoblast cytotoxicity and the accumulation of lipid peroxide, the mitochondria of osteoblast show the same morphology changes as the erastin treatment group, and the expression of ferroptosis-related proteins glutathione peroxidase 4 (GPX4) and cystine-glutamate antiporter (SLC7A11) is downregulated, but these effects were reversed by ferroptosis inhibitor ferrastatin-1 and iron chelator deferoxamine (DFO). Furthermore, western blot and real-time polymerase chain reaction were used to detect the expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1); osteogenic capacity was evaluated by alizarin red S staining and the expression of osteoprotegerin, osteocalcin, and alkaline phosphatase; the results showed that the expression levels of these proteins in osteoblasts with 1, 10, or 100 μM melatonins were significantly higher than the high glucose group, but after using Nrf2-SiRNA interference, the therapeutic effect of melatonin was significantly inhibited. We also performed in vivo experiments in a diabetic rat model treated with two concentrations of melatonin (10, 50 mg/kg). Dynamic bone histomorphometry and micro-CT were used to observe the rat bone microstructure, and the expression of GPX4 and Nrf2 was determined by immunohistochemistry. Here, we first report that high glucose induces ferroptosis via increased ROS/lipid peroxidation/glutathione depletion in type 2 diabetic osteoporosis. More importantly, melatonin significantly reduced the level of ferroptosis and improved the osteogenic capacity of MC3T3-E1 through activating the Nrf2/HO-1 pathway in vivo and in vitro.


2014 ◽  
Vol 34 (16) ◽  
pp. 3106-3119 ◽  
Author(s):  
Amaresh C. Panda ◽  
Kotb Abdelmohsen ◽  
Je-Hyun Yoon ◽  
Jennifer L. Martindale ◽  
Xiaoling Yang ◽  
...  

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Eric P van der Veer

The post-transcriptional events that enable monocytes to home to sites of vascular injury, and subsequently differentiate into macrophages within atherosclerotic lesions are poorly understood. We discovered that the mRNA and protein levels of the RNA-binding protein Quaking (QKI) are augmented in CD14+ myeloid cells extracted from advanced human atherosclerotic plaques (4.2-fold upregulated vs. early lesions; p<0.01). This prompted us to investigate how the RNA-binding properties of QKI could influence monocyte fate. Our approach was to examine, at a genome-wide level, how altering the expression levels of QKI could impact pre-mRNA splicing, expression, and localization upon differentiation of human monocytes into Mf. For this, we employed both array-based gene expression analyses as well as next-generation sequencing techniques (RNA-seq) of THP-1 monocytic cells as well as CD14+ monocytes derived from the peripheral blood of a unique, QKI haploinsufficient subject (with sibling control). Despite low expression levels of QKI in monocytes, the abrogation of QKI in these cells perturbed cellular adhesion and the ensuing establishment of the cytoskeletal architecture. Interestingly, our investigation of post-transcriptional events that are associated with the conversion of the monocyte to a macrophage, uncovered: 1) 536 alternative splicing events (p<0.05) that are directly mediated by binding of QKI proximal to the splice site (QBS)(Fig. 1A); and 2) 1214 differentially expressed genes (minimally +/- 1.5-fold; p<0.05) that indicate that QKI modulates monocyte activation and differentiation by regulating inflammation, cell growth and survival, RNA editing and lipid metabolism via activation of the LXR/RXR pathway (Fig. 1B). Collectively, our data illustrate the post-transcriptional events that drive monocyte to macrophage differentiation, and identify the RNA-binding protein QKI as an orchestrator of this inflammatory response.


2007 ◽  
Vol 177 (4S) ◽  
pp. 78-79
Author(s):  
Lioudmila Sitnikova ◽  
Gary Mendese ◽  
Qin Lui ◽  
Bruce A. Woda ◽  
Di Lu ◽  
...  

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