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Differentiation of Atrial Cardiomyocytes from Pluripotent Stem Cells Using the BMP Antagonist Grem2
Published on: March 10, 2016
miR-122-5p targets GREM2 to protect against glucocorticoid-induced endothelial damage through the BMP signaling
Xianzhe Huang1, Shuo Jie1, Wenzhao Li1
1Department of Orthopedics, The Second Xiangya Hospital, Central South University, Changsha, 410011, Hunan, China.
Abstract:
Glucocorticoid (GC)-induced osteonecrosis of the femoral head (ONFH) accounts for a big portion of non-traumatic ONFH; nevertheless, the pathogenesis has not yet been fully understood. GC-induced endothelial dysfunction might be a major contributor to ONFH progression. The Gene Expression Omnibus (GEO) dataset was analyzed to identify deregulated miRNAs in ONFH; among deregulated miRNAs, the physiological functions of miR-122-5p on ONFH and endothelial dysfunction remain unclear. In the present study, miR-122-5p showed to be under-expressed within GC-induced ONFH femoral head tissues and GC-stimulated bone microvascular endothelial cells (BMECs). In human umbilical vein endothelial cells (HUVECs) and BMECs, GC stimulation significantly repressed cell viability, promoted cell apoptosis and increased the mRNA expression of proinflammatory cytokines, such as TNF-α, IL-1β, and IFN-γ. After overexpressing miR-122-5p, GC-induced endothelial injuries were attenuated, as manifested by rescued cell viability, cell migration, and tube formation capacity. Regarding the BMP signaling, GC decreased the protein levels of BMP-2/6/7 and SMAD-1/5/8, whereas miR-122-5p overexpression significantly attenuated the inhibitory effects of GC on these proteins. Online tool and experimental analyses revealed the direct binding between miR-122-5p and GREM2, a specific antagonist of BMP-2. In contrast to miR-122-5p overexpression, GREM2 overexpression aggravated GC-induced endothelial injury; GREM2 silencing partially eliminated the effects of miR-122-5p inhibition on GC-stimulated HUVECs and BMECs. Finally, GREM2 silencing reversed the suppressive effects of GC on BMP-2/6/7 and SMAD-1/5/8, and attenuated the effects of miR-122-5p inhibition on these proteins upon GC stimulation. Conclusively, the present study demonstrates a miR-122-5p/GREM2 axis modulating the GC-induced endothelial damage via the BMP/SMAD signaling. Considering the critical role of endothelial function in ONFH pathogenesis, the in vivo role and clinical application of the miR-122-5p/GREM2 axis is worthy of further investigation.
Insights
Glucocorticoid-induced osteonecrosis of the femoral head (ONFH) involves endothelial dysfunction. This study identifies a miR-122-5p/GREM2 pathway that protects against GC-induced endothelial damage via BMP/SMAD signaling, offering potential therapeutic targets for ONFH.
Area of Science:
- Biomedical research
- Molecular biology
- Cell biology
Background:
- Glucocorticoid (GC)-induced osteonecrosis of the femoral head (ONFH) is a significant clinical issue with poorly understood pathogenesis.
- Endothelial dysfunction is implicated as a key factor in GC-induced ONFH progression.
- The role of miR-122-5p in GC-induced ONFH and endothelial dysfunction requires clarification.
Purpose of the Study:
- To investigate the function of miR-122-5p in glucocorticoid (GC)-induced osteonecrosis of the femoral head (ONFH).
- To elucidate the molecular mechanism of miR-122-5p in regulating GC-induced endothelial dysfunction.
- To identify the relationship between miR-122-5p, GREM2, and the BMP/SMAD signaling pathway in endothelial cells.
Main Methods:
- Analysis of Gene Expression Omnibus (GEO) datasets to identify deregulated miRNAs in ONFH.
- In vitro experiments using human umbilical vein endothelial cells (HUVECs) and bone microvascular endothelial cells (BMECs) stimulated with GCs.
- Overexpression and silencing of miR-122-5p and GREM2, followed by assessments of cell viability, apoptosis, migration, and tube formation.
- Western blot analysis to evaluate protein levels of BMP signaling pathway components (BMP-2/6/7, SMAD-1/5/8).
- Bioinformatic analysis and luciferase reporter assays to confirm the direct binding of miR-122-5p to GREM2.
Main Results:
- miR-122-5p was found to be underexpressed in GC-induced ONFH tissues and GC-stimulated endothelial cells.
- GC stimulation impaired endothelial cell viability, promoted apoptosis, and increased pro-inflammatory cytokine expression.
- Overexpression of miR-122-5p attenuated GC-induced endothelial injury and protected against BMP/SMAD pathway inhibition.
- miR-122-5p directly targets GREM2, a BMP-2 antagonist.
- GREM2 overexpression exacerbated GC-induced endothelial damage, while GREM2 silencing partially rescued endothelial function and reversed GC's effects on the BMP/SMAD pathway.
Conclusions:
- The study establishes a novel miR-122-5p/GREM2 axis that modulates GC-induced endothelial damage through the BMP/SMAD signaling pathway.
- miR-122-5p acts as a protective factor against GC-induced endothelial dysfunction.
- The miR-122-5p/GREM2 axis represents a potential therapeutic target for managing GC-induced ONFH, warranting further in vivo and clinical investigation.
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