PIEZO1 might be involved in cerebral ischemia-reperfusion injury through ferroptosis regulation: a hypothesis

The influence of ferroptosis on the in vitro OGD/R model in rat microglia

OBJECTIVE

We aimed to explore the influence of ferroptosis on an oxygen-glucose deprivation/reoxygenation (OGD/R) model in primary rat microglia.

METHODS

Primary microglia were extracted from rats and cultured in vitro. The cells were subjected to a hypoxic environment for 6 h in a glucose-free medium, and then re-oxygenated for 24 h in DMEM/F12. Rat microglia were pretreated with the ferroptosis activator erastin and the ferroptosis inhibitor ferrostatin 1 for 24 h, followed by detection of cell cycle progression and apoptosis by flow cytometry. Intracellular total iron levels were measured. In addition, the relative levels of reactive oxygen species (ROS), malondialdehyde (MDA), and superoxide dismutase (SOD) were determined using enzyme-linked immunosorbent assay. The protein levels of 15-lox2, GPX4, SLC7A11, ACSL4, and TFR1 were examined by western blotting.

RESULTS

Compared with rat microglia subjected to OGD/R, pretreatment with erastin did not influence cell apoptosis but significantly enhanced total iron levels, MDA, and ROS levels, whereas it reduced SOD levels. Moreover, it upregulated ACSL4, TFR1, and 15-lox2 and downregulated GPX4 and SLC7A11. Pretreatment with ferrostatin 1 significantly inhibited cell apoptosis and cell cycle arrest in the G0/G1 phase. It significantly reduced total iron levels, MDA, and ROS levels and enhanced SOD levels, which also downregulated ACSL4, TFR1, and 15-lox2, and upregulated GPX4 and SLC7A11.

CONCLUSION

Our study showed that inhibition of ferroptosis is favorable against potential OGD/R-induced damage in rat microglia.

Mechanobiological insight into brain diseases based on mechanosensitive channels: Common mechanisms and clinical potential

BACKGROUND

As physical signals, mechanical cues regulate the neural cells in the brain. The mechanosensitive channels (MSCs) perceive the mechanical cues and transduce them by permeating specific ions or molecules across the plasma membrane, and finally trigger a series of intracellular bioelectrical and biochemical signals. Emerging evidence supports that wide-distributed, high-expressed MSCs like Piezo1 play important roles in several neurophysiological processes and neurological disorders.

AIMS

To systematically conclude the functions of MSCs in the brain and provide a novel mechanobiological perspective for brain diseases.

METHOD

We summarized the mechanical cues and MSCs detected in the brain and the research progress on the functional roles of MSCs in physiological conditions. We then concluded the pathological activation and downstream pathways triggered by MSCs in two categories of brain diseases, neurodegenerative diseases and place-occupying damages. Finally, we outlined the methods for manipulating MSCs and discussed their medical potential with some crucial outstanding issues.

RESULTS

The MSCs present underlying common mechanisms in different brain diseases by acting as the "transportation hubs" to transduce the distinct signal patterns: the upstream mechanical cues and the downstream intracellular pathways. Manipulating the MSCs is feasible to alter the complicated downstream processes, providing them promising targets for clinical treatment.

CONCLUSIONS

Recent research on MSCs provides a novel insight into brain diseases. The common mechanisms mediated by MSCs inspire a wide range of therapeutic potentials targeted on MSCs in different brain diseases.

The endothelium: gatekeeper to lung ischemia-reperfusion injury

The success of lung transplantation is limited by the high rate of primary graft dysfunction due to ischemia-reperfusion injury (IRI). Lung IRI is characterized by a robust inflammatory response, lung dysfunction, endothelial barrier disruption, oxidative stress, vascular permeability, edema, and neutrophil infiltration. These events are dependent on the health of the endothelium, which is a primary target of IRI that results in pulmonary endothelial barrier dysfunction. Over the past 10 years, research has focused more on the endothelium, which is beginning to unravel the multi-factorial pathogenesis and immunologic mechanisms underlying IRI. Many important proteins, receptors, and signaling pathways that are involved in the pathogenesis of endothelial dysfunction after IR are starting to be identified and targeted as prospective therapies for lung IRI. In this review, we highlight the more significant mediators of IRI-induced endothelial dysfunction discovered over the past decade including the extracellular glycocalyx, endothelial ion channels, purinergic receptors, kinases, and integrins. While there are no definitive clinical therapies currently available to prevent lung IRI, we will discuss potential clinical strategies for targeting the endothelium for the treatment or prevention of IRI. The accruing evidence on the essential role the endothelium plays in lung IRI suggests that promising endothelial-directed treatments may be approaching the clinic soon. The application of therapies targeting the pulmonary endothelium may help to halt this rapid and potentially fatal injury.

Membrane Dynamics and Cation Handling in Ferroptosis

Ferroptosis, a regulated cell death hallmarked by excessive lipid peroxidation, is implicated in various (patho)physiological contexts. During ferroptosis, lipid peroxidation leads to a diverse change in membrane properties and the dysregulation of ion homeostasis via the cation channels, ultimately resulting in plasma membrane rupture. This review illuminates cellular membrane dynamics and cation handling in ferroptosis regulation.

Matrine induces ferroptosis in cervical cancer through activation of piezo1 channel

BACKGROUND

Cervical cancer, which is a significant public health concern in women, currently lacks effective therapeutic drugs. Matrine, a constituent of the traditional Chinese herb Sophora flavescentis Radix, is known for its anti-cervical cancer properties and ability to induce programmed cell death. The induction of cancer cell ferroptosis, which is a novel cell death pattern, can become an effective clinical therapy for tumor in the future. However, the effect of matrine on ferroptosis in cervical cancer remains to be elucidated.

PURPOSE

In this study, we investigated whether matrine induces ferroptosis in cervical cancer and elucidated the underlying mechanisms.

METHODS

We established an SiHa-derived tumor-bearing mouse model using CB17 severe combined immunodeficient (SCID) mice and administered a group of matrine (25, 50, and 75 mg/kg) and cisplatin (2 mg/kg). We meticulously tracked alterations in body weight and tumor size and evaluated liver and kidney health using haematoxylin and eosin (H&E) staining. Using Gene Expression Omnibus (GEO) Dataset (GSE201309), we evaluated the relationship between the effects of matrine on malignant tumor cells and ferroptosis. In vitro, tetrazolium-based colorimetric (MTT), lactate dehydrogenase (LDH) and colony formation assays were used to study the effects of matrine on SiHa cell activity and cytotoxicity. We assessed ferroptosis-related protein abundance using western blotting and ferroptosis-related indices in cells using confocal immunofluorescence microscopy. The interaction of matrine with a protein linked to ferroptosis was studied using cellular thermal shift assay (CETSA). The effects of matrine on Piezo1 expression were investigated using calcium imaging. We also used Piezo1-specific siRNA to explore the role of Piezo1 in ferroptosis.

RESULTS

Matrine administration effectively inhibited tumor growth in a SiHa-derived tumor-bearing mouse model without inducing noticeable harm. The analysis results of GEO data set show matrine-induced effects in tumor cells were indeed involved in the process of ferroptosis. Treatment with matrine resulted in a significant reduction in GPX4 protein levels and a concurrent increase in lipid peroxide and Fe2+ content, suggesting matrine-induced modulation of ferroptosis. Matrine promoted SiHa cell death in vitro, as evidenced by the results of MTT and LDH assays. Cell death coincides with increases in intracellular Fe2+, reactive oxygen species (ROS), and lipid peroxides. Our study also revealed significant upregulation of Piezo1 expression through the action of matrine, whereas transferrin receptor (Tfr) and System Xc- (xCT) expression and interaction remained unaffected. We provided further evidence that matrine induces calcium influx through the Piezo1 channel, thereby potentially influencing ferroptosis. Transfection with Piezo1 siRNA reversed the effects of matrine in SiHa cell.

CONCLUSIONS

Our findings indicate that matrine exerts a protective effect against cervical cancer by inducing ferroptosis through the activation of Piezo1, but not xCT or Tfr.

Mechanosensitive Piezo1 channel in physiology and pathophysiology of the central nervous system

Since the discovery of the mechanosensitive Piezo1 channel in 2010, there has been a significant amount of research conducted to explore its regulatory role in the physiology and pathology of various organ systems. Recently, a growing body of compelling evidence has emerged linking the activity of the mechanosensitive Piezo1 channel to health and disease of the central nervous system. However, the exact mechanisms underlying these associations remain inadequately comprehended. This review systematically summarizes the current research on the mechanosensitive Piezo1 channel and its implications for central nervous system mechanobiology, retrospects the results demonstrating the regulatory role of the mechanosensitive Piezo1 channel on various cell types within the central nervous system, including neural stem cells, neurons, oligodendrocytes, microglia, astrocytes, and brain endothelial cells. Furthermore, the review discusses the current understanding of the involvement of the Piezo1 channel in central nervous system disorders, such as Alzheimer's disease, multiple sclerosis, glaucoma, stroke, and glioma.

Mechanical properties of the brain: Focus on the essential role of Piezo1-mediated mechanotransduction in the CNS

BACKGROUND

The brain is a highly mechanosensitive organ, and changes in the mechanical properties of brain tissue influence many physiological and pathological processes. Piezo type mechanosensitive ion channel component 1 (Piezo1), a protein found in metazoans, is highly expressed in the brain and involved in sensing changes of the mechanical microenvironment. Numerous studies have shown that Piezo1-mediated mechanotransduction is closely related to glial cell activation and neuronal function. However, the precise role of Piezo1 in the brain requires further elucidation.

OBJECTIVE

This review first discusses the roles of Piezo1-mediated mechanotransduction in regulating the functions of a variety of brain cells, and then briefly assesses the impact of Piezo1-mediated mechanotransduction on the progression of brain dysfunctional disorders.

CONCLUSIONS

Mechanical signaling contributes significantly to brain function. Piezo1-mediated mechanotransduction regulates processes such as neuronal differentiation, cell migration, axon guidance, neural regeneration, and oligodendrocyte axon myelination. Additionally, Piezo1-mediated mechanotransduction plays significant roles in normal aging and brain injury, as well as the development of various brain diseases, including demyelinating diseases, Alzheimer's disease, and brain tumors. Investigating the pathophysiological mechanisms through which Piezo1-mediated mechanotransduction affects brain function will give us a novel entry point for the diagnosis and treatment of numerous brain diseases.

Sevoflurane preconditioning improves neuroinflammation in cerebral ischemia/reperfusion induced rats through ROS-NLRP3 pathway

AIM

We aimed to study the influence of sevoflurane on the nucleotide-binding domain and Leucine-rich repeat protein 3 (NLRP3) pathways in rats with cerebral ischemia/reperfusion (I/R) injury.

METHODS

Sixty Sprague-Dawley rats were equally divided into five groups randomly: sham-operated, cerebral I/R, sevoflurane (Sevo), NLRP3 inhibitor-treated (MCC950), and sevoflurane and NLRP3 inducer-treated groups. Rats' neurological functions were assessed using Longa scoring after 24 h of reperfusion, after which they were sacrificed, and cerebral infarction area was determined by triphenyl tetrazolium chloride staining. Pathological changes in damaged portions were assessed using hematoxylin-eosin and Nissl staining, and cell apoptosis was detected by terminal-deoxynucleotidyl transferase-mediated nick end labeling staining. Interleukin 1 beta (IL-1β), tumor necrosis factor α (TNF-α), interleukin-6 (IL-6), interleukin-18 (IL-18), malondialdehyde (MDA), and superoxide dismutase (SOD) levels in brain tissues were determined using enzyme-linked immunosorbent assay. Reactive oxygen species (ROS) levels were analyzed using a ROS assay kit. Protein levels of NLRP3, caspase-1, and IL-1β were determined by western blot.

RESULTS

Neurological function scores, cerebral infarction areas, and neuronal apoptosis index were decreased in the Sevo and MCC950 groups than in the I/R group. IL-1β, TNF-α, IL-6, IL-18, NLRP3, caspase-1, and IL-1β levels decreased in the Sevo and MCC950 groups (p < 0.05). ROS and MDA levels increased, but SOD levels increased in the Sevo and MCC950 groups than in the I/R group. NLPR3-inducer nigericin eliminated the protective effects of sevoflurane on cerebral I/R injury in rats.

CONCLUSION

Sevoflurane could alleviate cerebral I/R-induced brain damage by inhibiting the ROS-NLRP3 pathway.

MicroRNA-27a Regulates Ferroptosis Through SLC7A11 to Aggravate Cerebral ischemia-reperfusion Injury

Cerebral ischemia-reperfusion (I/R) injury is an inevitable issue in the treatment of ischemic stroke, which has a high disability rate and seriously threatens the living quality of patients. Previous studies have demonstrated that ferroptosis, which plays a crucial role in ischemia-reperfusion injury, can be accelerated by microRNA-27a (miR-27a). However, the mechanism by which miR-27a regulates ferroptosis in cerebral ischemia-reperfusion injury remains unknown. In this study, Male Sprague-Dawley rats were subjected to a middle cerebral artery occlusion (MCAO), then restored blood flow. Neurological function score and TTC staining were used to evaluate brain tissue injury and the infarct volume. The relative expression level of miR-27a was detected by qPCR. The relative expression levels of glutathione peroxidase 4(GPx4), solute carrier family 7 member 11 (SLC7A11) proteins were analyzed by Western Blot. The contents of GSH, Fe and malonaldehyde (MDA) were detected by corresponding detection kits, and the target gene of miR-27a was confirmed by dual luciferase reporter gene technique. It was found the relative expression level of miR-27a was increased and ferroptosis was aggravated as reperfusion time went by. Also, brain tissue injury and ferroptosis were exacerbated with agomiR-27a intervention, while these effects were reversed with antagomiR-27a intervention. In addition, the combined intervention of agomiR-27a and Fer-1 alleviated the brain tissue injury and ferroptosis. The results of dual luciferase reporter gene technique indicated SLC7A11 as the target gene of miR-27a. In the current study, miR-27a upregulates ferroptosis to aggravate cerebral ischemia-reperfusion injury by SLC7A11.

Activation of Meningeal Afferents Relevant to Trigeminal Headache Pain after Photothrombotic Stroke Lesion: A Pilot Study in Mice

Stroke can be followed by immediate severe headaches. As headaches are initiated by the activation of trigeminal meningeal afferents, we assessed changes in the activity of meningeal afferents in mice subjected to cortical photothrombosis. Cortical photothrombosis induced ipsilateral lesions of variable sizes that were associated with contralateral sensorimotor impairment. Nociceptive firing of mechanosensitive Piezo1 channels, activated by the agonist Yoda1, was increased in meningeal afferents in the ischemic hemispheres. These meningeal afferents also had a higher maximal spike frequency at baseline and during activation of the mechanosensitive Piezo1 channel by Yoda1. Moreover, in these meningeal afferents, nociceptive firing was active during the entire induction of transient receptor potential vanilloid 1 (TRPV1) channels by capsaicin. No such activation was observed on the contralateral hemi-skulls of the same group of mice or in control mice. Our data suggest the involvement of mechanosensitive Piezo1 channels capable of maintaining high-frequency spiking activity and of nociceptive TRPV1 channels in trigeminal headache pain responses after experimental ischemic stroke in mice.

Cell Death Mechanisms in Cerebral Ischemia-Reperfusion Injury

Ischemic stroke is one of the major causes of morbidity and mortality, affecting millions of people worldwide. Inevitably, the interruption of cerebral blood supply after ischemia may promote a cascade of pathophysiological processes. Moreover, the subsequent restoration of blood flow and reoxygenation may further aggravate brain tissue injury. Although recombinant tissue plasminogen activator (rt-PA) is the only approved therapy for restoring blood perfusion, the reperfusion injury and the narrow therapeutic time window restrict its application for most stroke patients. Increasing evidence indicates that multiple cell death mechanisms are relevant to cerebral ischemia-reperfusion injury, including apoptosis, necrosis, necroptosis, autophagy, pyroptosis, ferroptosis, and so on. Therefore, it is crucial to comprehend various cell death mechanisms and their interactions. In this review, we summarize the various signaling pathways underlying cerebral ischemia-reperfusion injury and elaborate on the crosstalk between the different mechanisms.

Bibliometric Analysis of Ferroptosis in Stroke From 2013 to 2021

Background: Stroke is a major cause of long-term disability and death, but the clinical therapeutic strategy for stroke is limited and more research must be conducted to explore the possible avenues for stroke treatment and recovery. Since ferroptosis is defined, its role in the body has become the focus of attention and discussion, including in stroke.

Methods: In this work, we aim to systematically discuss the “ferroptosis in stroke” research by bibliometric analysis. Documents were retrieved from the Web of Science Core Collection database on October 30, 2021. Statistical analysis and visualization analysis were conducted by the VOSviewer 1.6.15.

Results: Ninety-nine documents were identified for bibliometric analysis. Research on “ferroptosis in stroke” has been rapidly developing and has remained the focus of many scholars and organizations in the last few years, but the Chinese groups in this field still lacked collaboration with others. Documents and citation analysis suggested that Rajiv R. Ratan and Brent R. Stockwell are active researchers, and the research by Qingzhang Tuo, Ishraq Alim, and Qian Li are more important drivers in the development of the field. Keywords associated with lipid peroxidation, ferroptosis, iron, oxidative stress, and cell death had high frequency, but apoptosis, necroptosis, pyroptosis, and autophagy had scant research, and there may be more research ideas in the future by scholars.

Conclusion: Further exploration of the mechanisms of crosstalk between ferroptosis and other programmed cell death may improve clinical applications and therapeutic effects against stroke. Scholars will also continue to pay attention to and be interested in the hot topic “ferroptosis in stroke”, to produce more exciting results and provide new insights into the bottleneck of stroke treatment.

Tubeimoside I Ameliorates Myocardial Ischemia-Reperfusion Injury through SIRT3-Dependent Regulation of Oxidative Stress and Apoptosis

Myocardial ischemia-reperfusion injury (MIRI) is a phenomenon that reperfusion leads to irreversible damage to the myocardium and increases mortality in acute myocardial infarction (AMI) patients. There is no effective drug to treat MIRI. Tubeimoside I (TBM) is a triterpenoid saponin purified from Chinese traditional medicine tubeimu. In this study, 4 mg/kg TBM was given to mice intraperitoneally at 15 min after ischemia. And TBM treatment improved postischemic cardiac function, decreased infarct size, diminished lactate dehydrogenase release, ameliorated oxidative stress, and reduced apoptotic index. Notably, ischemia-reperfusion induced a significant decrease in cardiac SIRT3 expression and activity, while TBM treatment upregulated SIRT3's expression and activity. However, the cardioprotective effects of TBM were largely abolished by a SIRT3 inhibitor 3-(1H-1,2,3-triazol-4-yl) pyridine (3-TYP). This suggests that SIRT3 plays an essential role in TBM's cardioprotective effects. In vitro, TBM also protected H9c2 cells against simulated ischemia/reperfusion (SIR) injury by attenuating oxidative stress and apoptosis, and siSIRT3 diminished its protective effects. Taken together, our results demonstrate for the first time that TBM protects against MIRI through SIRT3-dependent regulation of oxidative stress and apoptosis. TBM might be a potential drug candidate for MIRI treatment.

Targeting Ferroptosis: Pathological Mechanism and Treatment of Ischemia-Reperfusion Injury

Ischemia-reperfusion (I/R) is a pathological process that occurs in many organs and diseases. Reperfusion, recovery of blood flow, and reoxygenation often lead to reperfusion injury. Drug therapy and early reperfusion therapy can reduce tissue injury and cell necrosis caused by ischemia, leading to irreversible I/R injury. Ferroptosis was clearly defined in 2012 as a newly discovered iron-dependent, peroxide-driven, nonapoptotic form of regulated cell death. Ferroptosis is considered the cause of reperfusion injury. This discovery provides new avenues for the recognition and treatment of diseases. Ferroptosis is a key factor that leads to I/R injury and organ failure. Given the important role of ferroptosis in I/R injury, there is considerable interest in the potential role of ferroptosis as a targeted treatment for a wide range of I/R injury-related diseases. Recently, substantial progress has been made in applying ferroptosis to I/R injury in various organs and diseases. The development of ferroptosis regulators is expected to provide new opportunities for the treatment of I/R injury. Herein, we analytically review the pathological mechanism and targeted treatment of ferroptosis in I/R and related diseases from the perspectives of myocardial I/R injury, cerebral I/R injury, and ischemic renal injury.