ATF3 Regulates Osteogenic Function by Mediating Osteoblast Ferroptosis in Type 2 Diabetic Osteoporosis

Abstract

Purpose. Osteoporosis is a complication of type 2 diabetes, and it is characterized by reduced bone mass, augmented bone fragility, and increased risk of fracture, thus reducing patient quality of life, especially in the elderly. Ferroptosis has been implicated in the pathological process of type 2 diabetic osteoporosis (T2DOP), but the specific underlying mechanisms remain largely unknown. This study clarified the role of activating transcription factor 3 (ATF3) in T2DOP and explored its specific regulatory mechanism, providing a new treatment target for T2DOP. Methods. We cultured hFob1.19 cells in high glucose (HG, 35 mM) and knocked down ATF3 using short hairpin RNA (shRNA). We then measured cell viability, assessed morphology, quantified the expression of ATF3 and glutathione peroxidase 4 (GPX4), detected the levels of reactive oxygen species (ROS) and lipid peroxides, and determined the osteogenic function of osteoblasts. Cystine/glutamate antiporter (system Xc-) activity was evaluated by determining the expression of SLC7A11 and the levels of glutathione (GSH) and extracellular glutamate. We constructed a T2DOP rat model and observed the effect of ATF3 on ferroptosis and T2DOP by knocking down ATF3 using small interfering RNA (siRNA). Then, we evaluated the levels of iron metabolism, lipid peroxidation, and bone turnover in serum, detected the expression of ATF3, SLC7A11, and GPX4 in bone tissues, and assessed bone microstructure using microcomputed tomography. Results. ATF3 expression was increased in osteoblasts under HG condition and in T2DOP rats. Inhibiting the function of ATF3 increased GPX4 levels and reduced the accumulation of ROS and lipid peroxides. These changes inhibited the ferroptosis of osteoblasts and improved osteogenic function. In addition, HG induced ATF3 upregulation, resulting in decreased SLC7A11 expression and lower levels of intracellular GSH and extracellular glutamate. Conclusion. Osteoblast ferroptosis under HG conditions is induced by ATF3-mediated inhibition of system Xc- activity, and these events contribute to T2DOP pathogenesis.

Identification of key genes and biological pathways in chronic obstructive pulmonary disease using bioinformatics and next generation sequencing data analysis

“…HBB (hemoglobin subunit beta) [52], HLA-DQA1 [53], EGR1 [54], ATF3 [55], XIST (X inactive specific transcript) [56], CD163 [57] and S100A8 [58] plays a crucial role in the pathogenesis of lung cancer and considered a promising target for pharmacological based therapies. HBB (hemoglobin subunit beta) [59], HBA1 [60], HLA-DQA1 [61], EGR1 [62], ATF3 [63], XIST (X inactive specific transcript) [64], S100A12 [65], CD163 [66] and S100A8 [67] are closely related to the progression of diabetes mellitus. HBA2 [68], HBA1 [68], EGR1 [69], XIST (X inactive specific transcript) [70], S100A12 [71] and CD163 [72] reported to play a central role in pulmonary hypertension.…”

“…LMNA (lamin A/C) [1313], VCAM1 [1299], PHGDH (phosphoglycerate dehydrogenase) [1382], S100A9 [81], TP63 [1312], FHL2 [1318], ATF3 [80] and MPO (myeloperoxidase) [1375] have been identified as a key genes in idiopathic pulmonary fibrosis. LMNA (lamin A/C) [1395], VCAM1 [1388], PHGDH (phosphoglycerate dehydrogenase) [1429] and ATF3 [63] might be a potential targets for osteoporosis. VCAM1 [126], S100A9 [168], FKBP5 [169], BPI (bactericidal permeability increasing protein) [176] and MPO (myeloperoxidase) [190] are mainly associated with COPD.…”

Lipolysis products from triglyceride‐rich lipoproteins induce stress protein ATF3 in osteoblasts

“…Recent studies suggest high expression of ATF3 in human preosteoblast cell populations using scRNAseq 56 . ATF3 expression was shown to be upregulated in a murine model of type 2 diabetes (T2D); in this model, T2D‐induced bone loss was reduced by treatment of mice with ATF3 siRNA 57 . Further, ATF3 has been identified as potential biomarker for the early diagnosis of osteoarthritis 58 .…”

“…ATF3 expression was shown to be upregulated in a murine model of type 2 diabetes (T2D); in this model, T2D-induced bone loss was reduced by treatment of mice with ATF3 siRNA. 57 Further, ATF3 has been identified as potential biomarker for the early diagnosis of osteoarthritis. 58 These new studies suggest there may be pivotal roles for ATF3 in bone and cartilage biology.…”

Programmed cell death of periodontal ligament cells

“…Findings indicate that a high‐glucose environment induces ferroptosis in osteoblasts. Osteoblasts cultured under high‐glucose conditions show increased levels of lipid peroxide ROS, decreased glutathione (GSH) and glutathione peroxidase 4 (GPX4), changes in mitochondrial morphology, and other ferroptosis‐related changes (Ma et al, 2020; Zhao, Du, et al, 2022). Studies further demonstrate that a high‐glucose and high‐fat environment also promote ferroptosis in osteoblasts, possibly via activation of the METTL3/ASK1‐p38 signaling pathway (Lin et al, 2022).…”