PIEZO1 Ion Channel Mediates Ionizing Radiation-Induced Pulmonary Endothelial Cell Ferroptosis via Ca2+/Calpain/VE-Cadherin Signaling

Abstract

Pulmonary endothelial cell dysfunction plays an important role in ionizing radiation (IR)-induced lung injury. Whether pulmonary endothelial cell ferroptosis occurs after IR and what are the underlying mechanisms remain elusive. Here, we demonstrate that 15-Gy IR induced ferroptosis characterized by lethal accumulation of reactive oxygen species (ROS), lipid peroxidation, mitochondria shrinkage, and decreased glutathione peroxidase 4 (GPX4) and SLC7A11 expression in pulmonary endothelial cells. The phenomena could be mimicked by Yoda1, a specific activator of mechanosensitive calcium channel PIEZO1. PIEZO1 protein expression was upregulated by IR in vivo and in vitro. The increased PIEZO1 expression after IR was accompanied with increased calcium influx and increased calpain activity. The effects of radiation on lung endothelial cell ferroptosis was partly reversed by inhibition of PIEZO1 activity using the selective inhibitor GsMTx4 or inhibition of downstreaming Ca2+/calpain signaling using PD151746. Both IR and activation of PIEZO1 led to increased degradation of VE-cadherin, while PD151746 blocked these effects. VE-cadherin knockdown by specific siRNA causes ferroptosis-like phenomena with increased ROS and lipid peroxidation in the lung endothelial cells. Overexpression of VE-cadherin partly recused the ferroptosis caused by IR or PIEZO1 activation as supported by decreased ROS production, lipid peroxidation and mitochondria shrinkage compared to IR or PIEZO1 activation alone. In summary, our study reveals a previously unrecognized role of PIEZO1 in modulating ferroptosis, providing a new target for future mitigation of radiation-induced lung injury.

Cooperation effects of radiation and ferroptosis on tumor suppression and radiation injury

“…In acute RILI, ferroptosis characteristics of mitochondria have been detected, together with substantial downregulation of GPX4 levels ( Li et al, 2019b ; Guo et al, 2021 ). Piezo-type mechanosensitive ion channel component 1 (PIEZO1) is a mechanically activated calcium channel highly expressed in lung tissue ( Coste et al, 2010 ).…”

“…Piezo-type mechanosensitive ion channel component 1 (PIEZO1) is a mechanically activated calcium channel highly expressed in lung tissue ( Coste et al, 2010 ). PIEZO1/Ca 2+ /calpain signaling mediates radiation-induced ferroptosis in pulmonary endothelial cells ( Guo et al, 2021 ) ( Figure 4 ). Radiation induces PIEZO1 protein overexpression, elevating intracellular Ca 2+ levels and activating the Ca 2+ /calpain signaling pathway.…”

“…Vascular endothelial cadherin (VE-cadherin) is a calcium-dependent adhesive molecule expressed only in endothelial cells ( Gory et al, 1999 ). Activation of the Ca 2+ /calpain signaling pathway can promote its degradation, leading to increased ROS content and ferroptosis ( Guo et al, 2021 ). However, the mechanism underlying VE-cadherin-induced ferroptosis has not been comprehensively investigated.…”

Ferroptosis of Endothelial Cells in Vascular Diseases

“…Ferroptosis of lung ECs modulated by piezo-type mechanosensitive ion channel component 1 (PIEZO1)/calcium (Ca 2+ )/calpain signaling was a potential therapeutic mechanism. Vascular endothelial-cadherin (VE-cadherin) knockdown caused ferroptosis-like phenomena in human pulmonary microvascular endothelial cells (HULEC-5a), whereas VE-cadherin overexpression partly decreased ferroptosis [ 66 ]. In addition to ALI, ferroptosis of pulmonary artery ECs (PAECs) is also involved in pulmonary hypertension (PH).…”

“…HMOX1 inhibition via genetic or pharmacological means may have the potential to attenuate ferroptosis [ 55 ]. PIEZO1/Ca 2+ /calpain signaling modulates ferroptosis of lung ECs, which is a potential therapeutic mechanism for treating radiation-induced lung injury [ 66 ]. Tripartite motif-containing 46 and GPX4 form a regulatory pathway that controls HG-induced ferroptosis of human retinal capillary ECs.…”