Effect of Piezo1 Overexpression on Peritumoral Brain Edema in Glioblastomas

Piezo1, the new actor in cell volume regulation

All animal cells control their volume through a complex set of mechanisms, both to counteract osmotic perturbations of the environment and to enable numerous vital biological processes, such as proliferation, apoptosis, and migration. The ability of cells to adjust their volume depends on the activity of ion channels and transporters which, by moving K+, Na+, and Cl- ions across the plasma membrane, generate the osmotic gradient that drives water in and out of the cell. In 2010, Patapoutian's group identified a small family of evolutionarily conserved, Ca2+-permeable mechanosensitive channels, Piezo1 and Piezo2, as essential components of the mechanically activated current that mediates mechanotransduction in vertebrates. Piezo1 is expressed in several tissues and its opening is promoted by a wide range of mechanical stimuli, including membrane stretch/deformation and osmotic stress. Piezo1-mediated Ca2+ influx is used by the cell to convert mechanical forces into cytosolic Ca2+ signals that control diverse cellular functions such as migration and cell death, both dependent on changes in cell volume and shape. The crucial role of Piezo1 in the regulation of cell volume was first demonstrated in erythrocytes, which need to reduce their volume to pass through narrow capillaries. In HEK293 cells, increased expression of Piezo1 was found to enhance the regulatory volume decrease (RVD), the process whereby the cell re-establishes its original volume after osmotic shock-induced swelling, and it does so through Ca2+-dependent modulation of the volume-regulated anion channels. More recently we reported that Piezo1 controls the RVD in glioblastoma cells via the modulation of Ca2+-activated K+ channels. To date, however, the mechanisms through which this mechanosensitive channel controls cell volume and maintains its homeostasis have been poorly investigated and are still far from being understood. The present review aims to provide a broad overview of the literature discussing the recent advances on this topic.

Piezo1 inhibitor isoquercitrin rescues neural impairment mediated by NLRP3 after intracerebral hemorrhage

In intracerebral hemorrhage (ICH), the mechanical brain injury is a considerable and indispensable factor determining the neurological functions and poor outcomes. Previous studies indicate the mechanically gated ion channel-Piezo1 can transduce mechanical effects following ICH. Isoquercitrin (ISQ) is a well-studied ion channel inhibitor. Furthermore, whether the following Piezo1-mediated neurological impairment can be ameliorated by ISQ remains unclear. Herein, we constructed the hydrostatic pressure model and ICH rat model. Firstly, we found that Piezo1 agonists Yoda1 and Jedi1 facilitated extracellular calcium influx dramatically, but ISQ could depress intracellular Ca2+ overload under hydrostatic pressure in primary neurons. Then we detected the expression profile of Piezo1, NLRP3 and NF-κB p-p65 after ICH, and found that the expression of Piezo1 was much earlier than NLRP3 and NF-κB p-p65. Furthermore, by western blot and immunofluorescence, ISQ decreased the expression of Piezo1 and NLRP3 dramatically like GsMTx4, but Nigericin as a NLRP3 agonist failed to affect Piezo1. Besides, both ISQ and interfering Piezo1 suppressed the upregulated caspase-1, NF-κB p-p65, p-IκBα, Tunel-positive cells and inflammatory factors (IL-1β, IL-6 and TNF-α) in ICH. At last, the hydrostatic pressure or hematoma induced disturbed neural viability, disordered neural cytomorphology, and increased neurobehavioral and cognitive deficits, but they were improved by ISQ and GsMTx4 strongly. Therefore, ISQ could alleviate neurological injuries induced by Piezo1 via NLRP3 pathway. These observations indicated that Piezos might be the new therapeutic targets, and blocking Piezos/NLRP3 pathway by ISQ could be an auspicious strategy for the treatment of ICH.

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.

Inhibition of piezo1 prevents chronic cerebral hypoperfusion-induced cognitive impairment and blood brain barrier disruption

Chronic cerebral hypoperfusion (CCH) plays a critical role in the onset and progression of vascular dementia (VD), which is now recognized as the second most common form of dementia after Alzheimer's disease (AD). The mechanosensitive piezo1 channel has been identified to play important roles in several neurological disorders. However, the roles and possible mechanisms of piezo1 in CCH-induced cognitive decline and blood brain barrier (BBB) disruption, as well as the underlying mechanisms remain elusive. In this study, the CCH model was established by bilateral common carotid artery occlusion in rats and by oxygen and glucose deprivation/reoxygenation (OGD/R) in bEnd.3 cells. The results demonstrated that the antagonist of piezo1 GsMTx4 ameliorated CCH-induced cognitive dysfunction and mitigated cerebral edema. Furthermore, this study indicated that GsMTx4 improved the permeability and integrity of BBB and protected cerebral microvasculature after CCH. In vitro, GsMTx4 improved cell viability, promoted the ability of cell motility and migration, and inhibited the degradation of BBB integrity-related proteins by inhibiting NLRP3 inflammasome activation. In addition, NLRP3 agonist abolished the beneficial effects of GsMTx4. Collectively, our results demonstrate that piezo1 might be involved in CCH-induced cognitive impairment and BBB damage, which may be at least partially mediated through regulation of NLRP3 inflammasome.

Pharmacological Activation of Piezo1 Channels Enhances Astrocyte-Neuron Communication via NMDA Receptors in the Murine Neocortex

The Piezo1 mechanosensitive ion channel is abundant on several elements of the central nervous system including astrocytes. It has been already demonstrated that activation of these channels is able to elicit calcium waves on astrocytes, which contributes to the release of gliotransmitters. Astrocyte- and N-methyl-D-aspartate (NMDA) receptor-dependent slow inward currents (SICs) are hallmarks of astrocyte-neuron communication. These currents are triggered by glutamate released as gliotransmitter, which in turn activates neuronal NMDA receptors responsible for this inward current having slower kinetics than any synaptic events. In this project, we aimed to investigate whether Piezo1 activation and inhibition is able to alter spontaneous SIC activity of murine neocortical pyramidal neurons. When the Piezo1 opener Yoda1 was applied, the SIC frequency and the charge transfer by these events in a minute time was significantly increased. These changes were prevented by treating the preparations with the NMDA receptor inhibitor D-AP5. Furthermore, Yoda1 did not alter the spontaneous EPSC frequency and amplitude when SICs were absent. The Piezo1 inhibitor Dooku1 effectively reverted the actions of Yoda1 and decreased the rise time of SICs when applied alone. In conclusion, activation of Piezo1 channels is able to alter astrocyte-neuron communication. Via enhancement of SIC activity, astrocytic Piezo1 channels have the capacity to determine neuronal excitability.

Mechanical Constraints in Tumor Guide Emergent Spatial Patterns of Glioblastoma Cancer Stem Cells

The mechanical constraints in the overcrowding glioblastoma (GBM) microenvironment have been implicated in the regulation of tumor heterogeneity and disease progression. Especially, such mechanical cues can alter cellular DNA transcription and give rise to a subpopulation of tumor cells called cancer stem cells (CSCs). These CSCs with stem-like properties are critical drivers of tumorigenesis, metastasis, and treatment resistance. Yet, the biophysical and molecular machinery underlying the emergence of CSCs in tumor remained unexplored. This work employed a two-dimensional micropatterned multicellular model to examine the impact of mechanical constraints arisen from geometric confinement on the emergence and spatial patterning of CSCs in GBM tumor. Our study identified distinct spatial distributions of GBM CSCs in different geometric patterns, where CSCs mostly emerged in the peripheral regions. The spatial pattern of CSCs was found to correspond to the gradients of mechanical stresses resulted from the interplay between the cell-ECM and cell-cell interactions within the confined environment. Further mechanistic study highlighted a Piezo1-RhoA-focal adhesion signaling axis in regulating GBM cell mechanosensing and the subsequent CSC phenotypic transformation. These findings provide new insights into the biophysical origin of the unique spatial pattern of CSCs in GBM tumor and offer potential avenues for targeted therapeutic interventions.

The role of ion channels in the relationship between the immune system and cancer

The immune system is capable of identifying and eliminating cancer, a complicated illness marked by unchecked cellular proliferation. The significance of ion channels in the complex interaction between the immune system and cancer has been clarified by recent studies. Ion channels, which are proteins that control ion flow across cell membranes, have variety of physiological purposes, such as regulating immune cell activity and tumor development. Immune cell surfaces contain ion channels, which have been identified to control immune cell activation, motility, and effector activities. The regulation of immune responses against cancer cells has been linked to a number of ion channels, including potassium, calcium, and chloride channels. As an example, potassium channels are essential for regulating T cell activation and proliferation, which are vital for anti-tumor immunity. Calcium channels play a crucial role when immune cells produce cytotoxic chemicals in order to eliminate cancer cells. Chloride channels also affect immune cell infiltration and invasion into malignancies. Additionally, tumor cells' own expressed ion channels have an impact on their behavior and in the interaction with the immune system. The proliferation, resistance to apoptosis, and immune evasion of cancer cells may all be impacted by changes in ion channel expression and function. Ion channels may also affect the tumor microenvironment by controlling angiogenesis, inflammatory responses, and immune cell infiltration. Ion channel function in the interaction between the immune system and cancer has important implications for cancer treatment. A possible method to improve anti-tumor immune responses and stop tumor development is to target certain ion channels. Small compounds and antibodies are among the ion channel modulators under investigation as possible immunotherapeutics. The complex interaction between ion channels, the immune system, and cancer highlights the significance of these channels for tumor immunity. The development of novel therapeutic strategies for the treatment of cancer will be made possible by unraveling the processes by which ion channels control immune responses and tumor activity. Hence, the main driving idea of the present chapter is trying to understand the possible function of ion channels in the complex crosstalk between cancer and immunoresponse. To this aim, after giving a brief journey of ion channels throughout the history, a classification of the main ion channels involved in cancer disease will be discussed. Finally, the last paragraph will focus on more recently advancements in the use of biomaterials as therapeutic strategy for cancer treatment. The hope is that future research will take advantage of the promising combination of ion channels, immunomodulation and biomaterials filed to provide better solutions in the treatment of cancer disease.

Mechanosensitive Ion Channels: Their Physiological Importance and Potential Key Role in Cancer

Mechanosensitive ion channels comprise a broad group of proteins that sense mechanical extracellular and intracellular changes, translating them into cation influx to adapt and respond to these physical cues. All cells in the organism are mechanosensitive, and these physical cues have proven to have an important role in regulating proliferation, cell fate and differentiation, migration and cellular stress, among other processes. Indeed, the mechanical properties of the extracellular matrix in cancer change drastically due to high cell proliferation and modification of extracellular protein secretion, suggesting an important contribution to tumor cell regulation. In this review, we describe the physiological significance of mechanosensitive ion channels, emphasizing their role in cancer and immunity, and providing compelling proof of the importance of continuing to explore their potential as new therapeutic targets in cancer research.

Ca2+ -activated K+ channels regulate cell volume in human glioblastoma cells

Glioblastoma (GBM), the most lethal form of brain tumors, bases its malignancy on the strong ability of its cells to migrate and invade the narrow spaces of healthy brain parenchyma. Cell migration and invasion are both critically dependent on changes in cell volume and shape driven by the transmembrane transport of osmotically important ions such as K+ and Cl- . However, while the Cl- channels participating in cell volume regulation have been clearly identified, the precise nature of the K+ channels involved is still uncertain. Using a combination of electrophysiological and imaging approaches in GBM U87-MG cells, we found that hypotonic-induced cell swelling triggered the opening of Ca2+ -activated K+ (KCa ) channels of large and intermediate conductance (BKCa and IKCa , respectively), both highly expressed in GBM cells. The influx of Ca2+ mediated by the hypotonic-induced activation of mechanosensitive channels was found to be a key step for opening both the BKCa and the IKCa channels. Finally, the activation of both KCa channels mediated by mechanosensitive channels was found to be essential for the development of the regulatory volume decrease following hypotonic shock. Taken together, these data indicate that KCa channels are the main K+ channels responsible for the volume regulation in U87-MG cells.

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.

Inflammation condition sensitizes Piezo1 mechanosensitive channel in mouse cerebellum astrocyte

Piezo1 mechanosensitive ion channel (MSC) plays a significant role in human physiology. Despite several research on the function and expression of Piezo1 in the nervous system, its electrophysiological properties in neuroinflammatory astrocytes remain unknown. We tested whether astrocytic neuroinflammatory state regulates Piezo1 using electrical recordings, calcium imaging, and wound healing assays on cultured astrocytes. In this study, we determined whether neuroinflammatory condition regulates astrocytic Piezo1 currents in astrocytes. First, we performed electrophysiological recordings on the mouse cerebellum astrocytes (C8-S) under lipopolysaccharide (LPS)-induced neuroinflammatory condition. We found that LPS treatment significantly increased MSC currents in C8-S. The half-maximal pressure of LPS treated MSC currents was left-shifted but the slope sensitivity was not altered by LPS treatment. LPS-induced increase of MSC currents were further augmented by Piezo1 agonist, Yoda1 but were normalized by Piezo1 inhibitor, GsMTx4. Furthermore, silencing Piezo1 in LPS treated C8-S normalized not only MSC currents but also calcium influx and cell migration velocity. Together, our results show that LPS sensitized Piezo1 channel in C8-S astrocytes. These findings will suggest that astrocytic Piezo1 is a determinant of neuroinflammation pathogenesis and may in turn become the foundation of further research into curing several neuronal illnesses and injury related inflammation of neuronal cells.

PIEZO1-Related Physiological and Pathological Processes in CNS: Focus on the Gliomas

PIEZO1 is ubiquitously expressed in cells in different kinds of tissues throughout the body, which can sense physical or mechanical stimuli and translate them into intracellular electrochemical signals to regulate organism functions. In particular, PIEZO1 appears in complex interactive regulatory networks as a central node, governing normal and pathological functions in the body. However, the effect and mechanism of the activation or expression of PIEZO1 in diseases of the central nervous system (CNS) remain unclear. On one hand, in CNS diseases, pathophysiological processes in neurons and glial are often accompanied by variations in the mechanical properties of the cellular and extracellular matrix stiffness. The expression of PIEZO1 can therefore be upregulated, in responding to mechanical stimulation, to drive the biological process in cells, which in turns indirectly affects the cellular microenvironment, resulting in alterations of the cellular status. On the other hand, it may have contradictory effects with the change of active patterns and/or subcellular location. This review highlights the biological processes involved with PIEZO1 in CNS cells, with special emphasis on its multiple roles in glioma-associated phenotypes. In conclusion, PIEZO1 can be used as an indicator to assess the malignancy and prognosis of patients with gliomas, as well as a therapeutic target for clinical application following fully exploring the potential mechanism of PIEZO1 in CNS diseases.

Mechanosensitive Ion Channels and Their Role in Cancer Cells

Mechanical forces are an inherent element in the world around us. The effects of their action can be observed both on the macro and molecular levels. They can also play a prominent role in the tissues and cells of animals due to the presence of mechanosensitive ion channels (MIChs) such as the Piezo and TRP families. They are essential in many physiological processes in the human body. However, their role in pathology has also been observed. Recent discoveries have highlighted the relationship between these channels and the development of malignant tumors. Multiple studies have shown that MIChs mediate the proliferation, migration, and invasion of various cancer cells via various mechanisms. This could show MIChs as new potential biomarkers in cancer detection and prognosis and interesting therapeutic targets in modern oncology. Our paper is a review of the latest literature on the role of the Piezo1 and TRP families in the molecular mechanisms of carcinogenesis in different types of cancer.

Mechanotransductive Receptor Piezo1 as a Promising Target in the Treatment of Neurological Diseases

In recent years, increasing attention has been paid to the role of physical factors in biological processes. This direction was ultimately confirmed by the recent 2021 Nobel Prize in medicine and physiology awarded in ½ to Ardem Patapoutian for his discovery of Piezo1 and Piezo2 mechanosensitive receptors. Among them, Piezo2 is responsible for sensing touch, while Piezo1 is engaged in a variety of mechanotransduction events. Piezo1 is expressed in various central nervous system cells, while its expression may be affected in the course of various pathological conditions. Recently, thanks to the development of Piezo1 modulators (i.e. Yoda1, Jedi1/2 and Dooku2), it is possible to study the role of Piezo1 in the pathogenesis of various neurological diseases including ischemia, glioma, and age-related dementias. The results obtained in this field suggest that proper modulation of Piezo1 receptor might be beneficial in the course of various neurological diseases.

Nomogram Model for Predicting the Prognosis of High-Grade Glioma in Adults Receiving Standard Treatment: A Retrospective Cohort Study

OBJECTIVES

To identify the critical factors associated with the progression-free survival (PFS) and overall survival (OS) of high-grade glioma (HGG) in adults who have received standard treatment and establish a novel graphical nomogram and an online dynamic nomogram.

PATIENTS AND METHODS

This is a retrospective study of adult HGG patients receiving standard treatment (surgery, postoperative radiotherapy, and temozolomide (TMZ) chemotherapy) at Huashan Hospital, Fudan University between January 2017 and December 2019. We used uni- and multi-variable COX models to identify the significant prognostic factors for PFS and OS. Based on the significant predictors, graphical and online nomograms were established.

RESULTS

A total of 246 patients were enrolled in the study based on the inclusion criteria. The average PFS and OS were 22.99 ± 11.43 and 30.51 ± 13.73 months, respectively. According to the multi-variable COX model, age, extent of resection (EOR), and IDH mutation were associated with PFS and OS, while edema index (EI) was relevant to PFS. In addition, patients with IDH and TERT promoter co-mutations had longer PFSs and OSs, and no apparent survival benefit was found in the long-cycle TMZ adjuvant chemotherapy compared with the standard Stupp protocol. Based on these critical factors, a graphical nomogram and online nomogram were developed for predicting PFS and OS, respectively. The calibration curve showed favorable consistency between the predicted and actual survival rates. C-index and time-dependent AUC showed good discrimination abilities.

CONCLUSIONS

We identified the significant predictors for the PFS and OS of HGG adults receiving standard treatment and established user-friendly nomogram models to assist neurosurgeons in optimizing clinical management and treatment strategies.

Transcription factor CASZ1 increases an oncogenic transcriptional process in tumorigenesis and progression of glioma cells

As a transcription factor, the role of CASZ1 in different entities is inconsistent. Glioma is one of the leading causes of cancer death worldwide. Its prognostic relevance and biological functions in glioma remain obscure. We focused on the role, mechanism, and prognostic value of CASZ1 in glioma cells. Herein, CASZ1 was identified as a novel potential oncogene in glioma tissues from GEO and TCGA datasets. CASZ1 was highly expressed in glioma tissues, predicting poor prognosis in glioma patients. Knockdown of CASZ1 inhibited proliferation and invasion in vitro, whereas upregulation of CASZ1 presented opposite results. Overexpression of CASZ1 increased transcriptional process of target gene p75NTR. CASZ1 was the potential transcriptional regulators for p75NTR. In addition, the p75NTR expression is essential for CASZ1 to exert its function as an oncogene. Our findings indicate that highly expressed CASZ1 in glioma cells acts as a pro‐oncogene factor in gliomas via regulating transcriptional process of target gene p75NTR, which was identified as an unfavorable prognostic marker in patients with gliomas. CASZ1 is expected to become a novel target for the treatment of gliomas.

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.

Mechanosensitive Ion Channel PIEZO1 Signaling in the Hall-Marks of Cancer: Structure and Functions

Simple Summary

Tumor cells obtain various unique characteristics, which known as hallmarks of cancers, including sustained proliferative signaling, apoptosis resistance, and metastasis. These characteristics are crucial for tumor cells survival and for supporting their rapid growth. Studies have revealed that tumorigenesis is also accompanied by alteration in mechanical properties. Tumor cells could sense various mechanical forces, such as compressive force, shear stress, and portal vein pressure, which in turn could affect tumor progression. Piezo1 is a mechanically sensitive ion channel protein that can be activated mechanically, and is closely related to various diseases. Recent studies showed that Piezo1 is overexpressed in numerous tumors and is associated with poor prognosis. Furthermore, previous studies revealed that Piezo1 mediates these cancer hallmarks, and thus links up mechanical forces with tumor progression. Therefore, the discovery of Piezo1 provides a new insight for elucidating the mechanism of tumor progression under a mechanical microenvironment.

Abstract

Tumor cells alter their characteristics and behaviors during tumorigenesis. These characteristics, known as hallmarks of cancer, are crucial for supporting their rapid growth, need for energy, and adaptation to tumor microenvironment. Tumorigenesis is also accompanied by alteration in mechanical properties. Cells in tumor tissue sense mechanical signals from the tumor microenvironment, which consequently drive the acquisition of hallmarks of cancer, including sustained proliferative signaling, evading growth suppressors, apoptosis resistance, sustained angiogenesis, metastasis, and immune evasion. Piezo-type mechanosensitive ion channel component 1 (Piezo1) is a mechanically sensitive ion channel protein that can be activated mechanically and is closely related to various diseases. Recent studies showed that Piezo1 mediates tumor development through multiple mechanisms, and its overexpression is associated with poor prognosis. Therefore, the discovery of Piezo1, which links-up physical factors with biological properties, provides a new insight for elucidating the mechanism of tumor progression under a mechanical microenvironment, and suggests its potential application as a tumor marker and therapeutic target. In this review, we summarize current knowledge regarding the role of Piezo1 in regulating cancer hallmarks and the underlying molecular mechanisms. Furthermore, we discuss the potential of Piezo1 as an antitumor therapeutic target and the limitations that need to be overcome.

PIEZO channels and newcomers in the mammalian mechanosensitive ion channel family

Many ion channels have been described as mechanosensitive according to various criteria. Most broadly defined, an ion channel is called mechanosensitive if its activity is controlled by application of a physical force. The last decade has witnessed a revolution in mechanosensory physiology at the molecular, cellular, and system levels, both in health and in diseases. Since the discovery of the PIEZO proteins as prototypical mechanosensitive channel, many proteins have been proposed to transduce mechanosensory information in mammals. However, few of these newly identified candidates have all the attributes of bona fide, pore-forming mechanosensitive ion channels. In this perspective, we will cover and discuss new data that have advanced our understanding of mechanosensation at the molecular level.

Contribution of Oxidative Stress Induced by Sonodynamic Therapy to the Calcium Homeostasis Imbalance Enhances Macrophage Infiltration in Glioma Cells

Simple Summary

Sonodynamic therapy (SDT) is a non-invasive technique that is based on the combination of a sonosensitizer and acoustic activation that destroys the mitochondrial respiratory chain, leading to increases in the levels of intracellular reactive oxygen species (ROS) and calcium overload as well as to the inhibition of proliferation, invasion, and promotion of the apoptosis of biologically more aggressive grade 4 glioma. This study aimed to better understand the calcium overload mechanism involved in SDT irradiation and killing gliomas as well as in lipid metabolism in aggressive glioma cells under the SDT treatment. In this study, we examined the hypothesis that the early application of the mechanosensitive Ca²⁺ channel Piezo1 antagonist (GsMTx4) could better promote the dissociation and polymerization of the Ca²⁺ lipid complex and further increase oxidative stress levels, leading to a better anti-tumor effect when SDT was used as a treatment. Moreover, Piezo1’s early closing state and intracellular calcium overload formation may be a key link that leads to the final tumor-infiltrating macrophages.

Abstract

Background: To better understand the Ca²⁺ overload mechanism of SDT killing gliomas, we examined the hypothesis that the early application of the mechanosensitive Ca²⁺ channel Piezo1 antagonist (GsMTx4) could have a better anti-tumor effect. Methods: The in vitro effect of low-energy SDT combined with GsMTx4 or agonist Yoda 1 on both the ROS-induced distribution of Ca²⁺ as well as on the opening of Piezo1 and the dissociation and polymerization of the Ca²⁺ lipid complex were assessed. The same groups were also studied to determine their effects on both tumor-bearing BALB/c-nude and C57BL/6 intracranial tumors, and their effects on the tumor-infiltrating macrophages were studied as well. Results: It was determined that ultrasound-activated Piezo1 contributes to the course of intracellular Ca²⁺ overload, which mediates macrophages (M1 and M2) infiltrating under the oxidative stress caused by SDT. Moreover, we explored the effects of SDT based on the dissociation of the Ca²⁺ lipid complex by inhibiting the expression of fatty acid binding protein 4 (FABP4). The Piezo1 channel was blocked early and combined with SDT treatment, recruited macrophages in the orthotopic transplantation glioma model. Conclusions: SDT regulates intracellular Ca²⁺ signals by upregulating Piezo1 leading to the inhibition of the energy supply from lipid and recruitment of macrophages. Therefore, intervening with the function of the Ca²⁺ channel on the glioma cell membrane in advance is likely to be the key factor to obtain a better effect combined with SDT treatment.

Mechanical Properties in the Glioma Microenvironment: Emerging Insights and Theranostic Opportunities

Gliomas represent the most common malignant primary brain tumors, and a high-grade subset of these tumors including glioblastoma are particularly refractory to current standard-of-care therapies including maximal surgical resection and chemoradiation. The prognosis of patients with these tumors continues to be poor with existing treatments and understanding treatment failure is required. The dynamic interplay between the tumor and its microenvironment has been increasingly recognized as a key mechanism by which cellular adaptation, tumor heterogeneity, and treatment resistance develops. Beyond ongoing lines of investigation into the peritumoral cellular milieu and microenvironmental architecture, recent studies have identified the growing role of mechanical properties of the microenvironment. Elucidating the impact of these biophysical factors on disease heterogeneity is crucial for designing durable therapies and may offer novel approaches for intervention and disease monitoring. Specifically, pharmacologic targeting of mechanical signal transduction substrates such as specific ion channels that have been implicated in glioma progression or the development of agents that alter the mechanical properties of the microenvironment to halt disease progression have the potential to be promising treatment strategies based on early studies. Similarly, the development of technology to measure mechanical properties of the microenvironment in vitro and in vivo and simulate these properties in bioengineered models may facilitate the use of mechanical properties as diagnostic or prognostic biomarkers that can guide treatment. Here, we review current perspectives on the influence of mechanical properties in glioma with a focus on biophysical features of tumor-adjacent tissue, the role of fluid mechanics, and mechanisms of mechanical signal transduction. We highlight the implications of recent discoveries for novel diagnostics, therapeutic targets, and accurate preclinical modeling of glioma.

BMAL1 may be involved in angiogenesis and peritumoral cerebral edema of human glioma by regulating VEGF and ANG2

The rhythm gene BMAL1 (Brain and Muscle ARNT-Like 1) may play an important role in glioma tolerance for anti-angiogenesis therapy. In humans with glioma of different pathological grades, BMAL1 expression was significantly different, and the expression of ANG2 (Angiopoietin 2) and VEGF (Vascular endothelial growth factor) was positively correlated with the expression of BMAL1. Additionally, BMAL1 expression is positively correlated with the microvascular density and peritumoral edema of glioma. According to in vitro experiments, silencing the expression of BMAL1 in primary glioma cells results in a decrease in the expression of VEGF. In contrast, overexpression of BMAL1 promotes the expression of ANG2 and VEGF via HIF-1a pathway. Therefore, BMAL1 likely participates in the angiogenesis of glioma by modulating ANG2 and VEGF expression, alters the therapeutic effect of anti-angiogenic treatments, and promotes peritumoral brain edema of glioma.

Reprint of: Mechanosensitive ion channels in cell migration

Cellular processes are initiated and regulated by different stimuli, including mechanical forces. Cell membrane mechanosensors represent the first step towards the conversion of mechanical stimuli to a biochemical or electrical response. Mechanosensitive (MS) ion channels form a growing family of ion gating channels that respond to direct physical force or plasma membrane deformations. A number of calcium (Ca²⁺) permeable MS channels are known to regulate the initiation, direction, and persistence of cell migration during development and tumour progression. While the evidence that links individual MS ion channels to cell migration is growing, a unified analysis of the molecular mechanisms regulated downstream of MS ion channel activation is lacking. In this review, we describe the MS ion channel families known to regulate cell migration. We discuss the molecular mechanisms that act downstream of MS ion channels with an emphasis on Ca²⁺ mediated processes. Finally, we propose the future directions and impact of MS ion channel activity in the field of cell migration.

The emerging role of mechanical and topographical factors in the development and treatment of nervous system disorders: dark and light sides of the force

Nervous system diseases are the subject of intensive research due to their association with high mortality rates and their potential to cause irreversible disability. Most studies focus on targeting the biological factors related to disease pathogenesis, e.g. use of recombinant activator of plasminogen in the treatment of stroke. Nevertheless, multiple diseases such as Parkinson’s disease and Alzheimer’s disease still lack successful treatment. Recently, evidence has indicated that physical factors such as the mechanical properties of cells and tissue and topography play a crucial role in homeostasis as well as disease progression. This review aims to depict these factors’ roles in the progression of nervous system diseases and consequently discusses the possibility of new therapeutic approaches. The literature is reviewed to provide a deeper understanding of the roles played by physical factors in nervous system disease development to aid in the design of promising new treatment approaches.

Physiology and Pathophysiology of Mechanically Activated PIEZO Channels

Nearly all structures in our body experience mechanical forces. At a molecular scale, these forces are detected by ion channels that function as mechanotransducers converting physical forces into electrochemical responses. Here we focus on PIEZOs, a family of mechanically activated ion channels comprising PIEZO1 and PIEZO2. The significance of these channels is highlighted by their roles in touch and pain sensation as well as in cardiovascular and respiratory physiology, among others. Moreover, mutations in PIEZOs cause somatosensory, proprioceptive, and blood disorders. The goal here is to present the diverse physiology and pathophysiology of these unique channels, discuss ongoing research and critical gaps in the field, and explore the pharmaceutical interest in targeting PIEZOs for therapeutic development.

Mechanosensitive ion channels in cell migration

Cellular processes are initiated and regulated by different stimuli, including mechanical forces. Cell membrane mechanosensors represent the first step towards the conversion of mechanical stimuli to a biochemical or electrical response. Mechanosensitive (MS) ion channels form a growing family of ion gating channels that respond to direct physical force or plasma membrane deformations. A number of calcium (Ca2+) permeable MS channels are known to regulate the initiation, direction, and persistence of cell migration during development and tumour progression. While the evidence that links individual MS ion channels to cell migration is growing, a unified analysis of the molecular mechanisms regulated downstream of MS ion channel activation is lacking. In this review, we describe the MS ion channel families known to regulate cell migration. We discuss the molecular mechanisms that act downstream of MS ion channels with an emphasis on Ca2+ mediated processes. Finally, we propose the future directions and impact of MS ion channel activity in the field of cell migration.

Piezo-type mechanosensitive ion channel component 1 (Piezo1) in human cancer

Piezo-type mechanosensitive ion channel component 1 (Piezo1) is a mechanosensitive ion channel protein that is evolutionarily conserved and multifunctional. It plays an important role as an oncogenic mediator in several malignant tumors. It mediates the proliferation, migration, and invasion of a variety of cancer cells through various mechanisms. Multiple studies have shown that the expression of Piezo1 is related to the clinical characteristics of senescence and cancer patients, making Piezo1 useful as a new biomarker for the diagnosis and prognosis of a variety of human cancers. Manipulating the expression or function of Piezo1 is a potential therapeutic strategy for different diseases. Piezo1 may be a promising tumor biomarker and therapeutic target. Here we review the biological function, mechanism of action, and potential clinical significance of Piezo1 in oncogenesis and progression.

A New Hope in Spinal Degenerative Diseases: Piezo1

As a newly discovered mechanosensitive ion channel protein, the piezo1 protein participates in the transmission of mechanical signals on the cell membrane and plays a vital role in mammalian biomechanics. Piezo1 has attracted widespread attention since it was discovered in 2010. In recent years, studies on piezo1 have gradually increased and deepened. In addition to the discovery that piezo1 is expressed in the respiratory, cardiovascular, gastrointestinal, and urinary systems, it is also stably expressed in cells such as mesenchymal stem cells (MSCs), osteoblasts, osteoclasts, chondrocytes, and nucleus pulposus cells that constitute vertebral bodies and intervertebral discs. They can all receive external mechanical stimulation through the piezo1 protein channel to affect cell proliferation, differentiation, migration, and apoptosis to promote the occurrence and development of lumbar degenerative diseases. Through reviewing the relevant literature of piezo1 in the abovementioned cells, this paper discusses the effect of piezo1 protein expression under mechanical stress stimuli on spinal degenerative disease, providing the molecular basis for the pathological mechanism of spinal degenerative disease and also a new basis, ideas, and methods for the prevention and treatment of this degenerative disease.

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

Stroke is associated with high mortality and extremely high disability rate. Regulating ferroptosis seems to be a promising way to treat ischemic stroke. After stroke, vasogenic edema exerts a mechanical force on surrounding structures, which could activate the mechanosensitive PIEZO1 channel. Our previous research has found that brain cortex PIEZO1 expression was increased in the rat model of middle cerebral artery occlusion (MCAO), and PIEZO1 regulated oxygen-glucose deprivation/reoxygenation (OGD/R) injury in neurons through the calcium signaling. Considering recent studies has identified HIF1α as an essential protein in PIEZO1/calcium signaling, ferroptosis regulation and cerebral ischemia, we herein hypothesize that PIEZO1 might be involved in cerebral ischemia-reperfusion injury through ferroptosis regulation.