scholarly journals Moderate Fluid Shear Stress Regulates Heme Oxygenase-1 Expression to Promote Autophagy and ECM Homeostasis in the Nucleus Pulposus Cells

Author(s):  
Sheng Chen ◽  
Lei Qin ◽  
Xiaohao Wu ◽  
Xuekun Fu ◽  
Sixiong Lin ◽  
...  
2021 ◽  
Author(s):  
Shashi Kant ◽  
Khanh-Van Tran ◽  
Miroslava Kvandova ◽  
Amada D. Caliz ◽  
Hyung-Jin Yoo ◽  
...  

Fluid shear stress (FSS) is known to mediate multiple phenotypic changes in the endothelium. Laminar FSS (undisturbed flow) is known to promote endothelial alignment to flow that is key to stabilizing the endothelium and rendering it resistant to atherosclerosis and thrombosis. The molecular pathways responsible for endothelial responses to FSS are only partially understood. Here we have identified peroxisome proliferator gamma coactivator-1α (PGC-1α) as a flow-responsive gene required for endothelial flow alignment in vitro and in vivo. Compared to oscillatory FSS (disturbed flow) or static conditions, laminar FSS (undisturbed flow) increased PGC-1α expression and its transcriptional co-activation. PGC-1α was required for laminar FSS-induced expression of telomerase reverse transcriptase (TERT) in vitro and in vivo via its association with ERRα and KLF4 on the TERT promoter. We found that TERT inhibition attenuated endothelial flow alignment, elongation, and nuclear polarization in response to laminar FSS in vitro and in vivo. Among the flow-responsive genes sensitive to TERT status was heme oxygenase-1 (HMOX1), a gene required for endothelial alignment to laminar FSS. Thus, these data suggest an important role for a PGC-1α-TERT-HMOX1 axis in the endothelial stabilization response to laminar FSS.


Author(s):  
Shashi Kant ◽  
Khanh-Van Tran ◽  
Miroslava Kvandova ◽  
Amada D. Caliz ◽  
Hyung-Jin Yoo ◽  
...  

Objective: Fluid shear stress (FSS) is known to mediate multiple phenotypic changes in the endothelium. Laminar FSS (undisturbed flow) is known to promote endothelial alignment to flow, which is key to stabilizing the endothelium and rendering it resistant to atherosclerosis and thrombosis. The molecular pathways responsible for endothelial responses to FSS are only partially understood. In this study, we determine the role of PGC1α (peroxisome proliferator gamma coactivator-1α)-TERT (telomerase reverse transcriptase)-HMOX1 (heme oxygenase-1) during shear stress in vitro and in vivo. Approach and Results: Here, we have identified PGC1α as a flow-responsive gene required for endothelial flow alignment in vitro and in vivo. Compared with oscillatory FSS (disturbed flow) or static conditions, laminar FSS (undisturbed flow) showed increased PGC1α expression and its transcriptional coactivation. PGC1α was required for laminar FSS-induced expression of TERT in vitro and in vivo via its association with ERRα(estrogen-related receptor alpha) and KLF (Kruppel-like factor)-4 on the TERT promoter. We found that TERT inhibition attenuated endothelial flow alignment, elongation, and nuclear polarization in response to laminar FSS in vitro and in vivo. Among the flow-responsive genes sensitive to TERT status, HMOX1 was required for endothelial alignment to laminar FSS. Conclusions: These data suggest an important role for a PGC1α-TERT-HMOX1 axis in the endothelial stabilization response to laminar FSS.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nabil A. Rashdan ◽  
Bo Zhai ◽  
Pamela C. Lovern

AbstractIncreased fluid shear stress (FSS) is a key initiating stimulus for arteriogenesis, the outward remodeling of collateral arterioles in response to upstream occlusion. Placental growth factor (PLGF) is an important arteriogenic mediator. We previously showed that elevated FSS increases PLGF in a reactive oxygen species (ROS)-dependent fashion both in vitro and ex vivo. Heme oxygenase 1 (HO-1) is a cytoprotective enzyme that is upregulated by stress and has arteriogenic effects. In the current study, we used isolated murine mesentery arterioles and co-cultures of human coronary artery endothelial cells (EC) and smooth muscle cells (SMC) to test the hypothesis that HO-1 mediates the effects of FSS on PLGF. HO-1 mRNA was increased by conditions of increased flow and shear stress in both co-cultures and vessels. Both inhibition of HO-1 with zinc protoporphyrin and HO-1 knockdown abolished the effect of FSS on PLGF. Conversely, induction of HO-1 activity increased PLGF. To determine which HO-1 product upregulates PLGF, co-cultures were treated with a CO donor (CORM-A1), biliverdin, ferric ammonium citrate (FAC), or iron-nitrilotriacetic acid (iron-NTA). Of these FAC and iron-NTA induced an increase PLGF expression. This study demonstrates that FSS acts through iron to induce pro-arteriogenic PLGF, suggesting iron supplementation as a novel potential treatment for revascularization.


2016 ◽  
Vol 100 ◽  
pp. S148
Author(s):  
Paraskevi-Maria Psefteli ◽  
Mark Fowler ◽  
Richard Draijer ◽  
Giovanni E. Mann ◽  
Richard Siow

2019 ◽  
Author(s):  
Haixiong Miao ◽  
Yicun Yao ◽  
Baoqing Ye ◽  
Libing Dai ◽  
Weiguo Liang

AbstractIntervertebral disc degeneration (IVDD) is a chronic disease that correlates with the deterioration of the nucleus pulposus (NP) cells. However, the molecular mechanism of IVDD remains unclear. In this study, we investigated the function of microRNA-222 in IVDD and the potential molecular mechanism. NP cells treated with fluid shear stress (FSS) were used to simulate a model of IVDD in vitro. MicroRNA-222 was significantly downregulated in NP cells stimulated with FSS compared with that in unstimulated NP cells. Human NP cells were also treated with FSS to induce their degeneration. The mRNA and protein levels of C-FOS, MEK, phosphorylated MEK5 (pMEK5), ERK5, and pERK5 were evaluated with RT-PCR and western blotting, respectively. Enzyme-linked immunosorbent assays were used to investigate type II collagen and Aggrecan expression. NP cell proliferation was determined with the Cell Counting Kit-8. MicroRNA-222 was significantly downregulated in NP cells treated with FSS. The production of c-Fos and MEK5 were markedly reduced or increased in NP cells transfected with the has-microRNA-222 mimic or inhibitor, respectively, whether or not they were stimulated with FSS. The overexpression or inhibition of microRNA-222 markedly accelerated or suppressed the apoptosis of FSS-stimulated NP cells, respectively. In the NP cells, the overexpression or inhibition of microRNA-222 massively inhibited or strengthened Aggrecan and type II collagen expression. Together, our data indicated that c-Fos was a target of microRNA-222, and was negatively regulated by microRNA-222 in NP cells. Our findings also suggested that microRNA-222 is a possible therapeutic target for IVDD because it regulates c-Fos.


2021 ◽  
Author(s):  
Nabil A. Rashdan ◽  
Bo Zhai ◽  
Pamela C. Lovern

Abstract Increased fluid shear stress (FSS) is a key initiating stimulus for arteriogenesis, the outward remodeling of collateral arterioles in response to upstream occlusion. Placental growth factor (PLGF) is an important arteriogenic mediator. We previously showed that elevated FSS increases PLGF in a reactive oxygen species (ROS)-dependent fashion both in vitro and ex vivo. Heme oxygenase 1 (HO-1) is a cytoprotective enzyme that is upregulated by stress and has arteriogenic effects. In the current study, we used isolated murine mesentery arterioles and cocultures of human coronary artery endothelial cells (EC) and smooth muscle cells (SMC) to test the hypothesis that HO-1 mediates the effects of FSS on PLGF. HO-1 mRNA was increased by conditions of increased flow and shear stress in both cocultures and vessels. Both inhibition of HO-1 with zinc protoporphyrin and HO-1 knockdown abolished the effect of FSS on PLGF. Conversely, induction of HO-1 activity increased PLGF. To determine which HO-1 product upregulates PLGF, cocultures were treated with a CO donor (CORM-A1), biliverdin, ferric ammonium citrate (FAC), or iron-nitrilotriacetic acid (iron-NTA). Of these FAC and iron-NTA induced an increase PLGF expression. This study demonstrates that FSS acts through iron to induce pro-arteriogenic PLGF, suggesting iron supplementation as a novel potential treatment for revascularization.


2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Dongping Ye ◽  
Weiguo Liang ◽  
Libing Dai ◽  
Yicun Yao

We first applied moderate fluid shear stress to nucleus pulposus cells. The correlation of AP-1 with type II collagen, proteoglycan, Cytokeratin 8 protein, MAP-1, MAP-2, and MAP-4 and the correlation of AP-1 with IL-1β, TNF-α, IL-6, IL-8, MIP-1, MCP-1, and NO were detected. Our results document that moderate fluid shear stress could activate the FAK-MEK5-ERK5-cFos-AP1 signaling pathway. AP1 could downregulate the construct factors of cytoskeleton such as type II collagen, proteoglycan, Cytokeratin 8 protein, MAP-1, MAP-2, and MAP-4 in nucleus pulposus cell after the fluid shear stress was loaded. AP1 could upregulate the inflammatory factors such as IL-1β, TNF-α, IL-6, IL-8, MIP-1, MCP-1, and NO in nucleus pulposus cell after the fluid shear stress was loaded. Taken together, our data suggested that moderate fluid shear stress may play an important role in the cytoskeleton of nucleus pulposus and surrounding inflammatory mediators by activating the FAK-MEK5-ERK5-cFos-AP1 signaling pathway, thereby affecting cell degeneration.


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