Mechanogenetics for the remote and noninvasive control of cancer immunotherapy

Advanced Strategies for Ultrasound Control and Applications in Sonogenetics and Gas Vesicle-Based Technologies: A Review

Control systems play an important role in the diagnosis and treatment of medicine. In contrast to light and magnetic fields, ultrasound has received much attention due to its non-invasive, cost-effective, convenient, and high spatiotemporal precision and deep-penetration characteristics. Some studies have developed special nanomaterials for therapy by controlling the production of reactive oxygen species through ultrasound irradiation. However, the complex functionalities and toxicity issues associated with these nanomaterials limit the development of ultrasound control systems. To overcome these challenges, ultrasound control systems based on synthetic biology have been developed, especially for sonogenetics and gas vesicles. The tunable thermal and mechanical effects of ultrasound act as the main triggering source, enabling engineered cells to perform sono-thermal or sono-mechanical genetic modifications in the targeted tissue. Based on an in-depth understanding of the relationship between ultrasound effects and the design, composition, and applications of engineered cellular technologies, in this review, we focus on recent activation strategies of ultrasound for sonogenetics and gas vesicles, including sono-thermal promoter switch, sono-thermal transient receptor potential channel, sono-mechanical activation and gas vesicles. In addition, applications of these advanced ultrasound control systems for cancer therapy, neural activity, visual recovery and functional imaging are presented. Finally, we discuss the current challenges faced and provide an outlook on the future developments in this evolving field.

Progress and potential of nanobubbles for ultrasound-mediated drug delivery

INTRODUCTION

Despite much progress, nanomedicine-based drug therapies in oncology remain limited by systemic toxicity and insufficient particle accumulation in the tumor. To address these barriers, formulations responsive to external physical stimuli have emerged. One most promising system is the ultrasound stimulation of drug-loaded, gas-core particles (bubbles). Ultrasound induces bubble cavitation for cell and tissue permeabilization, triggers on-demand drug release, and provides opportunities for real-time imaging of delivery.

AREAS COVERED

Here, we focus on shell-stabilized, gas-core nanoparticles (also termed nanobubbles or ultrafine bubbles) and their role in ultrasound-mediated therapeutic delivery to tumors. This review frames the advantages of nanobubbles within the ongoing deficits in nanomedicine, describes mechanisms of ultrasound-mediated therapy, and details formulation techniques for nanobubble delivery systems. It then highlights the past decade of research in nanobubble-facilitated drug delivery for cancer therapy and anticipates new directions in the field.

EXPERT OPINION

Nanobubble ultrasound contrast agents offer a spatiotemporally triggerable therapeutic coupled with a safe, accessible imaging modality. Nanobubbles can be loaded with diverse therapeutic cargoes to treat disease and overcome numerous barriers limiting delivery to solid tumors. Close attention to formulation, characterization methods, acoustic testing parameters, and the biological mechanisms of nanobubble delivery will facilitate preclinical research toward clinical adoption.

Ultrasound-assisted immunotherapy for malignant tumour

Malignant tumour represents a significant global public health concern. The advent of immunotherapy has brought about a revolutionary shift in the landscape of tumour treatment, offering a ray of hope to patients across the globe. Immunotherapy strategies have demonstrated considerable promise in clinical trials. However, the immunosuppressive environment within the tumour microenvironment has constituted a significant obstacle to the advancement of immunotherapies. It is therefore imperative to develop more efficacious and personalised approaches. The utilisation of non-invasive ultrasound-assisted immunotherapy represents a promising strategy. Ultrasound has the capacity to induce an immune response and stimulate other drugs to achieve a specific response, thereby reducing the toxic side effects of treatment and enhancing the outcome of immunotherapy. This paper presents a systematic introduction to the various mechanisms related to ultrasound and reviews the recent advancements of ultrasound-assisted tumour immunotherapy, including ultrasonic ablation, combined application with contrast agents, and sonodynamic therapy.

Remote Control of Eukaryotic Gene Expression by a Modular Ultrasound-Responsive RNA Toolkit

Achieving remote control of biological processes remains a significant challenge in genetics. Although ultrasound has been employed to remotely regulate biological functions by targeting mechanosensitive ion channels, existing systems are constrained by the limited responsiveness of specific channels to specific ultrasound frequencies and their applicability to only a few cell types. Sonogenetics has shown promise for promoter control, thereby regulating gene transcription in eukaryotes. Here, we introduce a new modular toolkit for regulating gene expression using ultrasound-responsive RNA carriers capable of releasing small molecule modulators in response to a broad spectrum of ultrasound frequencies. The cells contain engineered mRNA structures encoding riboswitches or aptazymes, which respond specifically to these small molecule modulators finally controlling downstream protein expression by biocompatible ultrasound. This toolkit is versatile, functioning across various eukaryotic systems-from yeast to mammalian cells-and offers control over gene expression by regulating mRNA translation. We demonstrated that this sonogenetic toolkit robustly modulates gene expression, achieving up to a six-fold downregulation of protein levels in response to ultrasound stimulation. By expanding the application of sonogenetics across eukaryotes, this RNA-based toolkit might provide a promising platform for remotely controlling protein function in specific tissues through on-demand ultrasound activation in the future.

Novel strategies to manage CAR-T cell toxicity

The immune-related adverse events associated with chimeric antigen receptor (CAR)-T cell therapy result in substantial morbidity as well as considerable cost to the health-care system, and can limit the use of these treatments. Current therapeutic strategies to manage immune-related adverse events include interleukin-6 receptor (IL-6R) blockade and corticosteroids. However, because these interventions do not always address the side effects, nor prevent progression to higher grades of adverse events, new approaches are needed. A deeper understanding of the cell types involved, and their associated signalling pathways, cellular metabolism and differentiation states, should provide the basis for alternative strategies. To preserve treatment efficacy, cytokine-mediated toxicity needs to be uncoupled from CAR-T cell function, expansion, long-term persistence and memory formation. This may be achieved by targeting CAR or independent cytokine signalling axes transiently, and through novel T cell engineering strategies, such as low-affinity CAR-T cells, reversible on-off switches and versatile adaptor systems. We summarize the current management of cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome, and review T cell- and myeloid cell-intrinsic druggable targets and cellular engineering strategies to develop safer CAR-T cells.

Living Microalgae-Based Magnetic Microrobots for Calcium Overload and Photodynamic Synergetic Cancer Therapy

The combination of Ca2+ overload and reactive oxygen species (ROS) production for cancer therapy offers a superior solution to the lack of specificity in traditional antitumor strategies. However, current therapeutic platforms for this strategy are primarily based on non-targeting nanomaterials, leading to undesirable off-target side effects. Additionally, resistance to ROS and apoptosis induced by the hypoxic tumor microenvironment (TME) further limits therapeutic efficiency. Herein, a magnetic microrobot based on living Spirulina Platensis (SP), which is coated with a double layer of Fe3O4 nanoparticles (NPs) and CaCO3 NPs. The microrobots can accumulate in tumor regions under magnetic attraction, which produces a high-Ca2+ environment under the acidic TME and facilitates Ca2+ overload under ultrasound (US) stimulation. Meanwhile, sufficient oxygen (O2) production by photosynthesis helps alleviate hypoxia and promotes in situ ROS production by chlorophyll-mediated photodynamic therapy (PDT), which can coordinate with Ca2+ overload to induce cell apoptosis. With these unique properties, the SP-based microrobots offer a promising microrobotics-based strategy for in situ Ca2+ accumulation and ROS production, contributing to a precise and effective way for cancer treatment.

A mediator-free sonogenetic switch for therapeutic protein expression in mammalian cells

An ultrasound-responsive transgene circuit can provide non-invasive, spatiotemporally precise remote control of gene expression and cellular behavior in synthetic biology applications. However, current ultrasound-based systems often rely on nanoparticles or harness ultrasound's thermal effects, posing risks of tissue damage and cellular stress that limit their therapeutic potential. Here, we present Spatiotemporal Ultrasound-induced Protein Expression Regulator (SUPER), a novel gene switch enabling mediator-free, non-invasive and direct regulation of protein expression via ultrasound in mammalian cells. SUPER leverages the mammalian reactive oxygen species (ROS) sensing system, featuring KEAP1 (Kelch-like ECH-associated protein 1), NRF2 (nuclear factor erythroid 2-related factor 2), and antioxidant response element (ARE) as its core components. We demonstrate that low-intensity (1.5 W/cm2, ∼45 kHz), brief (40 s) ultrasound exposure generates non-toxic levels of ROS, activating the KEAP1/NRF2 pathway in engineered cells and leading to the controlled expression of target gene(s) via a synthetic ARE promoter. The system exhibits robust expression dynamics, excellent reversibility, and functionality in various cell types, including human mesenchymal stem cell-derived lines (hMSC-TERT). In a proof-of-concept study, ultrasound stimulation of subcutaneously implanted microencapsulated engineered cells stably expressing the sonogenetic circuit in a type 1 diabetic mouse model triggered sufficient insulin production to restore normoglycemia. Our work highlights ultrasound's potential as a precise and non-invasive tool for advancing cell and gene therapies in personalized medicine.

Programmable solid-state condensates for spatiotemporal control of mammalian gene expression

Engineering of nuclear condensates with chemically inducible gene switches is highly desired but challenging for precise and on-demand regulation of mammalian gene expression. Here, we harness the phase-separation capability of biomolecular condensates and describe a versatile strategy to chemically program ligand-dependent gene expression at various stages of interest. By engineering synthetic anchor proteins capable of tethering various genetically encoded condensate structures toward different cellular compartments or gene products of interest, inducible regulation of transcriptional and translational activities was achieved at different endogenous and episomal loci using the same sets of anchor proteins and synthetic solid-state condensates. Using such a holistic condensate-based strategy, we not only achieved regulation performances comparing favorably to state-of-the-art strategies described for CRISPR-Cas9 activity and transcriptional silencing but further showed that chemically inducible retention of mRNA molecules into engineered condensate structures within the nucleus can become a remarkably efficient alternative for translational regulation.

Inhibition of autophagy promotes ultrasound‑targeted microbubble destruction-induced apoptosis of pancreatic cancer cells

In therapeutic studies of pancreatic cancer, ultrasound-targeted microbubble destruction (UTMD) has shown potential in promoting apoptosis as a safe and non-invasive adjuvant therapy. Autophagy, a regulatory mechanism for cellular stress response and survival, plays a dual role in tumor development, progression, and treatment. However, the role of autophagy in UTMD-induced apoptosis in pancreatic cancer cells remains unclear. In this study, chloroquine (CQ), an autophagy inhibitor, was combined with UTMD to treat pancreatic cancer both in vitro and in vivo, with changes in apoptosis assessed through Western blot and TUNEL staining. The results showed that UTMD induced both apoptosis and autophagy in pancreatic cancer cells. Notably, inhibiting autophagy significantly enhanced UTMD-induced apoptosis, while the inhibition of apoptosis did not affect UTMD-induced autophagy. These findings suggest that autophagy reduces the effectiveness of UTMD in treating pancreatic cancer. This study offers a new perspective on UTMD for treating pancreatic cancer, suggesting that combining autophagy inhibitors could be a promising strategy to enhance the effectiveness of pancreatic cancer therapy.

Precise modulation of cell activity using sono-responsive nano-transducers

Ultrasound, as a form of mechanical energy, possesses a distinctive ability to deeply penetrate tissues, allowing for non-invasive manipulation of cellular activities. Utilizing nanomaterials in conjunction with ultrasound has enabled simple, efficient, spatiotemporally controllable, and minimally invasive regulation of cellular activities with ultrasound-generated electric, optical, acoustic, or chemical stimuli at the localized nanomaterials interface. This technology allows for precise and localized regulation of cellular activities, which is essential for studying and understanding complex biological processes, and also provides new opportunities for research, diagnostics, and therapeutics in the fields of biology and medicine. In this article, we review the state-of-the-art and ongoing developments in nanomaterials-enabled ultrasound cellular modulation, highlighting potential applications and advancements achieved through the integration of sono-responsive nanomaterials with ultrasound.

Mechanoimmunology of T-Cell Activation

T-cell activation, a pivotal process in the adaptive immune response, is initiated when the T cell receptor (TCR) recognises and binds to antigenic peptide-major histocompatibility complex (pMHC) molecules on the cell membrane. Emerging evidence indicates that mechanical cues regulate T-cell activation by modulating TCR signalling and mechanotransduction pathways, although the precise underlying mechanisms remain elusive. This review highlights recent findings suggesting that the TCR functions as a mechanosensor, capable of sensing and transmitting mechanical forces through conformational changes. Key steps in T-cell mechanotransduction are discussed, including the roles of the cytoskeleton, mechanosensitive channels such as Piezo 1 and microvilli in facilitating activation. Additionally, we analyse the mechanical responses of chimeric antigen receptor T cells. Understanding the mechanobiological mechanisms underlying T-cell activation offers novel insights and potential strategies for advancing immunotherapies and treating immune-related disorders.

A Mechanical Immune Checkpoint Inhibitor Stiffens Tumor Cells to Potentiate Antitumor Immunity

Tumor progression is associated with tumor-cell softening. Improving the stiffness of the tumor cells can make them more vulnerable to lymphocyte-mediated attack. Tumor cell membranes typically exhibit higher cholesterol levels than normal cells, making tumor cells soft. Herein, we demonstrate a mechanical immune checkpoint inhibitor (MICI) formulated by cyclodextrin (CD) lipids and fusogenic lipids. Through fusing CD lipids into the tumor cell membrane using a fusogenic liposome formulation, the cholesterol in the plasma membrane is reduced due to the specific host-guest interactions between CD lipid and cholesterol. As a result, tumor cells are stiffened, and the activation of lymphocytes (including NK and cytotoxic effector T cells) is improved when contacting the stiffened tumor cells, characterized by robust degranulation and effector cytokine production. Notably, this treatment has negligible influence on the infiltration and proliferation of lymphocytes in tumor tissues, confirming that the enhanced antitumor efficacy should result from activating a specific number of lymphocytes caused by direct regulation of the tumor cell stiffness. The combination of MICIs and clinical immunotherapies enhances the lymphocyte-mediated antitumor effects in two tumor mouse models, including breast cancer and melanoma. Our research also reveals an unappreciated mechanical dimension to lymphocyte activation.

Programming mammalian cell behaviors by physical cues

In recent decades, the field of synthetic biology has witnessed remarkable progress, driving advances in both research and practical applications. One pivotal area of development involves the design of transgene switches capable of precisely regulating specified outputs and controlling cell behaviors in response to physical cues, which encompass light, magnetic fields, temperature, mechanical forces, ultrasound, and electricity. In this review, we delve into the cutting-edge progress made in the field of physically controlled protein expression in engineered mammalian cells, exploring the diverse genetic tools and synthetic strategies available for engineering targeting cells to sense these physical cues and generate the desired outputs accordingly. We discuss the precision and efficiency limitations inherent in these tools, while also highlighting their immense potential for therapeutic applications.

Reversible Ca2+ signaling and enhanced paracellular transport in endothelial monolayer induced by acoustic bubbles and targeted microbeads

Ultrasound and microbubble mediated blood brain barrier opening is a non-invasive and effective technique for drug delivery to targeted brain region. However, the exact mechanisms are not fully resolved. The influences of Ca2+ signaling on sonoporation and endothelial tight junctional regulation affect the efficiency and biosafety of the technique. Therefore, an improved understanding of how ultrasound evokes Ca2+ signaling in the brain endothelial monolayer, and its correlation to endothelial permeability change is necessary. Here, we examined the effects of SonoVue microbubbles or integrin-targeted microbeads on ultrasound induced bioeffects in brain microvascular endothelial monolayer using an acoustically-coupled microscopy system, where focused ultrasound exposure and real-time recording of Ca2+ signaling and membrane perforation were performed. Microbubbles induced robust Ca2+ responses, often accompanied by cell poration, while ultrasound with microbeads elicited reversible Ca2+ response without membrane poration. At the conditions evoking reversible Ca2+ signaling, intracellular Ca2+ release and reactive oxygen species played key roles for microbubbles induced Ca2+ signaling while activation of mechanosensitive ion channels was essential for the case of microbeads. Trans-well diffusion analysis revealed significantly higher trans-endothelial transport of 70 kDa FITC-dextran for both integrin-targeted microbeads and microbubbles compared to the control group. Further immunofluorescence staining showed disruption of cell junctions with microbubble stimulation and reversible remodeling of many cell junctions by ultrasound with integrin-targeted microbeads. This investigation provides new insights for ultrasound induced Ca2+ signaling and its influence on endothelial permeability, which may help develop new strategies for safe and efficient drug/gene delivery in the vascular system.

Engineering signalling pathways in mammalian cells

In mammalian cells, signalling pathways orchestrate cellular growth, differentiation and survival, as well as many other processes that are essential for the proper functioning of cells. Here we describe cutting-edge genetic-engineering technologies for the rewiring of signalling networks in mammalian cells. Specifically, we describe the recombination of native pathway components, cross-kingdom pathway transplantation, and the development of de novo signalling within cells and organelles. We also discuss how, by designing signalling pathways, mammalian cells can acquire new properties, such as the capacity for photosynthesis, the ability to detect cancer and senescent cell markers or to synthesize hormones or metabolites in response to chemical or physical stimuli. We also review the applications of mammalian cells in biocomputing. Technologies for engineering signalling pathways in mammalian cells are advancing basic cellular biology, biomedical research and drug discovery.

Force versus Response: Methods for Activating and Characterizing Mechanosensitive Ion Channels and GPCRs

Mechanotransduction is the process whereby cells convert mechanical signals into electrochemical responses, where mechanosensitive proteins mediate this interaction. To characterize these critical proteins, numerous techniques have been developed that apply forces and measure the subsequent cellular responses. While these approaches have given insight into specific aspects of many such proteins, subsequent validation and cross-comparison between techniques remain difficult given significant variations in reported activation thresholds and responses for the same protein across different studies. Accurately determining mechanosensitivity responses for various proteins, however, is essential for understanding mechanotransduction and potential physiological implications, including therapeutics. This critical review provides an assessment of current and emerging approaches used for mechanosensitive ion channel and G-Coupled Receptors (GPCRs) stimulation and measurement, with a specific focus on the ability to quantitatively measure mechanosensitive responses.

Harnessing mechanobiology to enhance cell therapy

Recent developments in cell therapy have revolutionized medical treatment. While various methods of stimulation have been explored, the role of mechanical force has often been overlooked. Although mechanical loading is not easily visible, it can actively reshape organisms, and abnormal mechanical loading can lead to injury and disease. By leveraging the mechanobiology of cells, we can equip them with synthetic mechanosensors that can redirect genetic circuits to express protective factors, such as antibodies and cytokines, according to the mechanical force signal. The advancement of artificial intelligence (AI) presents a fascinating opportunity to redesign more complex mechanoreceptors, allowing cells to respond to intricate stimuli. Additionally, genetic engineering tools like CRISPR-Cas9, base editing, and prime editing enable the creation of multiple gene circuits for cells to react to complex mechanical environments. Advanced mechanical loading techniques, such as focused ultrasound, deliver signals in a confined spatial and temporal manner. Therefore, harnessing mechanobiology in cells can develop more flexible, personalized, and precise cell therapies.

Medical Ultrasound Application Beyond Diagnosis: Insights From Ultrasound Sensing and Biological Response

Ultrasound (US) can easily penetrate media with excellent spatial precision corresponding to its wavelength. Naturally, US plays a pivotal role in the echolocation abilities of certain mammals such as bats and dolphins. In addition, medical US generated by transducers interact with tissues via delivering ultrasonic energy in the modes of heat generation, exertion of acoustic radiation force (ARF), and acoustic cavitation. Based on the principle of echolocation, various assistive devices for visual impairment people have been developed. High-Intensity Focused Ultrasound (HIFU) are developed for targeted ablation and tissue destruction. Besides thermal ablation, histotripsy with US is designed to damage tissue purely via mechanical effect without thermal coagulation. Low-Intensity Focused Ultrasound (LIFU) has been proven to be an effective stimulation method for neuromodulation. Furthermore, US has been reported to transiently increase the permeability of biological membranes, enabling acoustic transfection and blood-brain barrier open. All of these advances in US are changing the clinic. This review mainly introduces the advances in these aspects, focusing on the physical and biological principles, challenges, and future direction.

Advances in ligand-based surface engineering strategies for fine-tuning T cell mechanotransduction toward efficient immunotherapy

T cell-based immunotherapy has recently emerged as a promising strategy to treat cancer, requiring the activation of antigen-directed cytotoxicity to eliminate cancer cells. Mechanical signaling, although often overshadowed by its biochemical counterpart, plays a crucial role in T cell anticancer responses, from activation to cytolytic killing. Rapid advancements in the fields of chemistry, biomaterials, and micro/nanoengineering offer an interdisciplinary approach to incorporating mechano- and immunomodulatory ligands, including but not limited to synthetic peptides, small molecules, cytokines, and artificial antigens, onto the biomaterial-based platforms to modulate mechanotransducive processes in T cells. The surface engineering of these immunomodulatory ligands with optimization of ligand density, geometrical arrangement, and mobility has been proven to better mimic the natural ligation between immunoreceptors and ligands to directly enhance or inhibit mechanotransduction pathways in T cells, through triggering upstream mechanosensitive channels, adhesion molecules, cytoskeletal components, or downstream mechanoimmunological regulators. Despite its tremendous potential, current research on this new biomaterial surface engineering approach for mechanomodulatory T cell activation and effector functions remains in a nascent stage. This review highlights the recent progress in this new direction, focusing on achievements in mechanomodulatory ligand-based surface engineering strategies and underlying principles, and outlooks the further research in the rapidly evolving field of T cell mechanotransduction engineering for efficient immunotherapy.

Significant Advancements and Evolutions in Chimeric Antigen Receptor Design

Recent times have witnessed remarkable progress in cancer immunotherapy, drastically changing the cancer treatment landscape. Among the various immunotherapeutic approaches, adoptive cell therapy (ACT), particularly chimeric antigen receptor (CAR) T cell therapy, has emerged as a promising strategy to tackle cancer. CAR-T cells are genetically engineered T cells with synthetic receptors capable of recognising and targeting tumour-specific or tumour-associated antigens. By leveraging the intrinsic cytotoxicity of T cells and enhancing their tumour-targeting specificity, CAR-T cell therapy holds immense potential in achieving long-term remission for cancer patients. However, challenges such as antigen escape and cytokine release syndrome underscore the need for the continued optimisation and refinement of CAR-T cell therapy. Here, we report on the challenges of CAR-T cell therapies and on the efforts focused on innovative CAR design, on diverse therapeutic strategies, and on future directions for this emerging and fast-growing field. The review highlights the significant advances and changes in CAR-T cell therapy, focusing on the design and function of CAR constructs, systematically categorising the different CARs based on their structures and concepts to guide researchers interested in ACT through an ever-changing and complex scenario. UNIVERSAL CARs, engineered to recognise multiple tumour antigens simultaneously, DUAL CARs, and SUPRA CARs are some of the most advanced instances. Non-molecular variant categories including CARs capable of secreting enzymes, such as catalase to reduce oxidative stress in situ, and heparanase to promote infiltration by degrading the extracellular matrix, are also explained. Additionally, we report on CARs influenced or activated by external stimuli like light, heat, oxygen, or nanomaterials. Those strategies and improved CAR constructs in combination with further genetic engineering through CRISPR/Cas9- and TALEN-based approaches for genome editing will pave the way for successful clinical applications that today are just starting to scratch the surface. The frontier lies in bringing those approaches into clinical assessment, aiming for more regulated, safer, and effective CAR-T therapies for cancer patients.

Multifunctional Nanomaterials Mediate Cholesterol Depletion for Cancer Treatment

Cholesterol is an essential membrane component, and the metabolites from cholesterol play important biological functions to intricately support cancer progression and dampen immune responses. Preclinical and clinical studies have demonstrated the role of cholesterol metabolism regulation on inhibiting tumor growth, remodeling the immunosuppressive tumor microenvironment (TME), and enhancing anti-tumor immunity. In this minireview, we discuss complex cholesterol metabolism in tumors, its important role in cancer progression, and its influences on immune cells in the TME. We provide an overview of recent advances in cancer treatment through regulating cholesterol metabolism. We discuss the design of cholesterol-altering multifunctional nanomaterials to regulate oxidative stress, modulate immune checkpoints, manipulate mechanical stress responses, and alter cholesterol metabolic pathways. Additionally, we examine the interactions between cholesterol metabolism regulation and established cancer treatments with the aim of identifying efficient strategies to disrupt cholesterol metabolism and synergistic combination therapies for effective cancer treatment.

Pancreatic ductal adenocarcinoma cells reshape the immune microenvironment: Molecular mechanisms and therapeutic targets

Pancreatic ductal adenocarcinoma (PDAC) is a digestive system malignancy characterized by challenging early detection, limited treatment alternatives, and generally poor prognosis. Although there have been significant advancements in immunotherapy for hematological malignancies and various solid tumors in recent decades, with impressive outcomes in recent preclinical and clinical trials, the effectiveness of these therapies in treating PDAC continues to be modest. The unique immunological microenvironment of PDAC, especially the abnormal distribution, complex composition, and variable activation states of tumor-infiltrating immune cells, greatly restricts the effectiveness of immunotherapy. Undoubtedly, integrating data from both preclinical models and human studies helps accelerate the identification of reliable molecules and pathways responsive to targeted biological therapies and immunotherapies, thereby continuously optimizing therapeutic combinations. In this review, we delve deeply into how PDAC cells regulate the immune microenvironment through complex signaling networks, affecting the quantity and functional status of immune cells to promote immune escape and tumor progression. Furthermore, we explore the multi-modal immunotherapeutic strategies currently under development, emphasizing the transformation of the immunosuppressive environment into an anti-tumor milieu by targeting specific molecular and cellular pathways, providing insights for the development of novel treatment strategies.

Compressive stresses in cancer: characterization and implications for tumour progression and treatment

Beyond their many well-established biological aberrations, solid tumours create an abnormal physical microenvironment that fuels cancer progression and confers treatment resistance. Mechanical forces impact tumours across a range of biological sizes and timescales, from rapid events at the molecular level involved in their sensing and transmission, to slower and larger-scale events, including clonal selection, epigenetic changes, cell invasion, metastasis and immune response. Owing to challenges with studying these dynamic stimuli in biological systems, the mechanistic understanding of the effects and pathways triggered by abnormally elevated mechanical forces remains elusive, despite clear correlations with cancer pathophysiology, aggressiveness and therapeutic resistance. In this Review, we examine the emerging and diverse roles of physical forces in solid tumours and provide a comprehensive framework for understanding solid stress mechanobiology. We first review the physiological importance of mechanical forces, especially compressive stresses, and discuss their defining characteristics, biological context and relative magnitudes. We then explain how abnormal compressive stresses emerge in tumours and describe the experimental challenges in investigating these mechanically induced processes. Finally, we discuss the clinical translation of mechanotherapeutics that alleviate solid stresses and their potential to synergize with chemotherapy, radiotherapy and immunotherapies.

Templated Pluripotent Stem Cell Differentiation via Substratum-Guided Artificial Signaling

The emerging field of synthetic morphogenesis implements synthetic biology tools to investigate the minimal cellular processes sufficient for orchestrating key developmental events. As the field continues to grow, there is a need for new tools that enable scientists to uncover nuances in the molecular mechanisms driving cell fate patterning that emerge during morphogenesis. Here, we present a platform that combines cell engineering with biomaterial design to potentiate artificial signaling in pluripotent stem cells (PSCs). This platform, referred to as PSC-MATRIX, extends the use of programmable biomaterials to PSCs competent to activate morphogen production through orthogonal signaling, giving rise to the opportunity to probe developmental events by initiating morphogenetic programs in a spatially constrained manner through non-native signaling channels. We show that the PSC-MATRIX platform enables temporal and spatial control of transgene expression in response to bulk, soluble inputs in synthetic Notch (synNotch)-engineered human PSCs for an extended culture of up to 11 days. Furthermore, we used PSC-MATRIX to regulate multiple differentiation events via material-mediated artificial signaling in engineered PSCs using the orthogonal ligand green fluorescent protein, highlighting the potential of this platform for probing and guiding fate acquisition. Overall, this platform offers a synthetic approach to interrogate the molecular mechanisms driving PSC differentiation that could be applied to a variety of differentiation protocols.

Mechanosensitive Ion Channels Piezo1 and Piezo2 Mediate Motor Responses In Vivo During Transcranial Focused Ultrasound Stimulation of the Rodent Cerebral Motor Cortex

OBJECTIVE

Transcranial focused ultrasound (tFUS) neuromodulation offers a noninvasive, safe, deep brain stimulation with high precision, presenting potential in understanding neural circuits and treating brain disorders. This in vivo study investigated the mechanism of tFUS in activating the opening of the mechanosensitive ion channels Piezo1 and Piezo2 in the mouse motor cortex to induce motor responses.

METHODS

Piezo1 and Piezo2 were knocked down separately in the mouse motor cortex, followed by EMG and motor cortex immunofluorescence comparisons before and after knockdown under tFUS stimulation.

RESULTS

The results demonstrated that the stimulation-induced motor response success rates in Piezo knockdown mice were lower compared to the control group (Piezo1 knockdown: 57.63% ± 14.62%, Piezo2 knockdown: 73.71% ± 13.10%, Control mice: 85.69% ± 10.23%). Both Piezo1 and Piezo2 knockdowns showed prolonged motor response times (Piezo1 knockdown: 0.62 ± 0.19 s, Piezo2 knockdown: 0.60 ± 0.13 s, Control mice: 0.44 ± 0.12 s) compared to controls. Additionally, Piezo knockdown animals subjected to tFUS showed reduced immunofluorescent c-Fos expression in the target area when measured in terms of cells per unit area compared to the control group.

CONCLUSION

This in vivo study confirms the pivotal role of Piezo channels in tFUS-induced neuromodulation, highlighting their influence on motor response efficacy and timing.

SIGNIFICANCE

This study provides insights into the mechanistic underpinnings of noninvasive brain stimulation techniques and opens avenues for developing targeted therapies for neural disorders.

Unveiling the Role of Mechanical Microenvironment in Hepatocellular Carcinoma: Molecular Mechanisms and Implications for Therapeutic Strategies

Hepatocellular carcinoma (HCC) is the sixth most common cancer in the world and the third leading cause of cancer deaths globally. More than 80% of HCC patients have a background of fibrosis or cirrhosis, which leads to changes in physical factors in tumor microenvironment (TME), such as increased stiffness, solid stress, fluid stresses and structural alterations in the extracellular matrix (ECM). In the past, the focus of cancer research has predominantly been on genetic and biochemical factors in the TME, and the critical role of physical factors has often been overlooked. Recent discoveries suggest these unique physical signals are converted into biochemical signals through a mechanotransduction process that influences the biological behavior of tumor cells and stromal cells. This process facilitates the occurrence and progression of tumors. This review delves into the alterations in the mechanical microenvironment during the progression of liver fibrosis to HCC, the signaling pathways activated by physical signals, and the effects on both tumor and mesenchymal stromal cells. Furthermore, this paper summarizes and discusses the therapeutic options for targeting the mechanical aspects of the TME, offering valuable insights for future research into novel therapeutic avenues against HCC and other solid tumors.

Regulation of Cell Membrane Potential through Supramolecular System for Activating Calcium Ion Channels

The regulation of the cell membrane potential plays a crucial role in governing the transmembrane transport of various ions and cellular life processes. However, in situ and on-demand modulation of cell membrane potential for ion channel regulation is challenging. Herein, we have constructed a supramolecular assembly system based on water-soluble cationic oligo(phenylenevinylene) (OPV) and cucurbit[7]uril (CB[7]). The controllable disassembly of OPV/4CB[7] combined with the subsequent click reaction provides a step-by-step adjustable surface positive potential. These processes can be employed in situ on the plasma membrane to modulate the membrane potential on-demand for precisely controlling the activation of the transient receptor potential vanilloid 1 (TRPV1) ion channel and up-regulating exogenous calcium-responsive gene expression. Compared with typical optogenetics, electrogenetics, and mechanogenetics, our strategy provides a perspective supramolecular genetics toolbox for the regulation of membrane potential and downstream intracellular gene regulation events.

Identification of Hub Genes in Comorbidity of Psoriasis and Vitiligo Using Bioinformatics Analysis

Background

Psoriasis and vitiligo are two common autoimmune skin diseases with increased risk of comorbidities, but the common molecular mechanism about the occurrence of these two diseases is still unknown.

Objective

This study aimed to identify the combined genetic profiles and evaluate the potential mechanism underlying the occurrence of this complication.

Methods

The Gene Expression Omnibus (GEO) database was used to obtain the gene expression profiles of psoriasis (GSE30999) and vitiligo (GSE75819), and common differentially expressed genes (DEGs) were identified using GEO2R. DEGs were analyzed using functional enrichment analysis, protein-protein interaction (PPI) network and module construction, hub gene identification, and co-expression analysis. And hub genes were identified using Cytoscape software, and the gene expression of hub genes were validated in psoriasis (GSE13355) and vitiligo (GSE65127) datasets and immunohistochemistry at the clinical sample.

Results

A total of 164 common DEGs with the same trend (137 upregulated and 27 downregulated) were selected for subsequent analysis. Functional analysis emphasized the important roles of the cell cycle and mitotic cell division, cytoskeletal reorganization, and chromatin remodeling in the complications of these two diseases. Fourteen important hub genes were identified, including BUB1, CEP55, CDK1, TOP2A, CENPF, PBK, MELK, CCNB2, MAD2L1, NUSAP1, TTK, NEK2, CDKN3, and PTTG1. Cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) may be an important immune checkpoint in the pathogenesis of the comorbidities.

Conclusion

Our study identified hub genes and potential mechanisms underlying psoriasis and vitiligo complications. And we proposed a new spatio-temporal theory and the probable immune checkpoint for the pathogenesis of the comorbidity which may provide new ideas for the further research.

Transcranial focused ultrasound precise neuromodulation: a review of focal size regulation, treatment efficiency and mechanisms

Ultrasound is a mechanical wave that can non-invasively penetrate the skull to deep brain regions to activate neurons. Transcranial focused ultrasound neuromodulation is a promising approach, with the advantages of noninvasiveness, high-resolution, and deep penetration, which developed rapidly over the past years. However, conventional transcranial ultrasound's spatial resolution is low-precision which hinders its use in precision neuromodulation. Here we focus on methods that could increase the spatial resolution, gain modulation efficiency at the focal spot, and potential mechanisms of ultrasound neuromodulation. In this paper, we summarize strategies to enhance the precision of ultrasound stimulation, which could potentially improve the ultrasound neuromodulation technic.

Recent advancement of sonogenetics: A promising noninvasive cellular manipulation by ultrasound

Recent advancements in biomedical research have underscored the importance of noninvasive cellular manipulation techniques. Sonogenetics, a method that uses genetic engineering to produce ultrasound-sensitive proteins in target cells, is gaining prominence along with optogenetics, electrogenetics, and magnetogenetics. Upon stimulation with ultrasound, these proteins trigger a cascade of cellular activities and functions. Unlike traditional ultrasound modalities, sonogenetics offers enhanced spatial selectivity, improving precision and safety in disease treatment. This technology broadens the scope of non-surgical interventions across a wide range of clinical research and therapeutic applications, including neuromodulation, oncologic treatments, stem cell therapy, and beyond. Although current literature predominantly emphasizes ultrasonic neuromodulation, this review offers a comprehensive exploration of sonogenetics. We discuss ultrasound properties, the specific ultrasound-sensitive proteins employed in sonogenetics, and the technique's potential in managing conditions such as neurological disorders, cancer, and ophthalmic diseases, and in stem cell therapies. Our objective is to stimulate fresh perspectives for further research in this promising field.

Ultrasound-mediated spatial and temporal control of engineered cells in vivo

Remote regulation of cells in deep tissue remains a significant challenge. Low-intensity pulsed ultrasound offers promise for in vivo therapies due to its non-invasive nature and precise control. This study uses pulsed ultrasound to control calcium influx in mammalian cells and engineers a therapeutic cellular device responsive to acoustic stimulation in deep tissue without overexpressing calcium channels or gas vesicles. Pulsed ultrasound parameters are established to induce calcium influx in HEK293 cells. Additionally, cells are engineered to express a designed calcium-responsive transcription factor controlling the expression of a selected therapeutic gene, constituting a therapeutic cellular device. The engineered sonogenetic system's functionality is demonstrated in vivo in mice, where an implanted anti-inflammatory cytokine-producing cellular device effectively alleviates acute colitis, as shown by improved colonic morphology and histopathology. This approach provides a powerful tool for precise, localized control of engineered cells in deep tissue, showcasing its potential for targeted therapeutic delivery.

Mechanoimmune-Driven Backpack Sustains Dendritic Cell Maturation for Synergistic Tumor Radiotherapy

Cell backpacks present significant potential in both therapeutic and diagnostic applications, making it essential to further explore their interactions with host cells. Current evidence indicates that backpacks can induce sustained immune responses. Our original objective was to incorporate a model antigen into the backpacks to promote dendritic cell maturation and facilitate antigen presentation, thereby inducing immune responses. However, we unexpectedly discovered that both antigen-loaded backpacks and empty backpacks demonstrated comparable abilities to induce dendritic cell maturation, resulting in nearly identical potency in T-cell proliferation. Our mechanistic studies suggest that the attachment of backpacks induces mechanical forces on dendritic cells via opening the PIEZO1 mechanical ion channel. This interaction leads to the remodeling of the intracellular cytoskeleton and facilitates the production of type I interferons by dendritic cells. Consequently, the mechano-immune-driven dendritic cell backpacks, when combined with radiotherapy, induce a robust antitumor effect. This research presents an avenue for leveraging mechanotransduction to enhance combination immunotherapeutic strategies, potentially leading to groundbreaking advancements in the field.

The principles and promising future of sonogenetics for precision medicine

Sonogenetics is an emerging medical technology that uses acoustic waves to control cells through sonosensitive mediators (SSMs) that are genetically encoded, thus remotely and non-invasively modulating specific molecular events and/or biomolecular functions. Sonogenetics has opened new opportunities for targeted spatiotemporal manipulation in the field of gene and cell-based therapies due to its inherent advantages, such as its noninvasive nature, high level of safety, and deep tissue penetration. Sonogenetics holds impressive potential in a wide range of applications, from tumor immunotherapy and mitigation of Parkinsonian symptoms to the modulation of neural reward pathway, and restoration of vision. This review provides a detailed overview of the mechanisms and classifications of established sonogenetics systems and summarizes their applications in disease treatment and management. The review concludes by highlighting the challenges that hinder the further progress of sonogenetics, paving the way for future advances.

Synthetic biology approaches for enhancing safety and specificity of CAR-T cell therapies for solid cancers

CAR-T cell therapies have been successful in treating numerous hematologic malignancies as the T cell can be engineered to target a specific antigen associated with the disease. However, translating CAR-T cell therapies for solid cancers is proving more challenging due to the lack of truly tumor-associated antigens and the high risk of off-target toxicities. To combat this, numerous synthetic biology mechanisms are being incorporated to create safer and more specific CAR-T cells that can be spatiotemporally controlled with increased precision. Here, we seek to summarize and analyze the advancements for CAR-T cell therapies with respect to clinical implementation, from the perspective of synthetic biology and immunology. This review should serve as a resource for further investigation and growth within the field of personalized cellular therapies.

Protein Gas Vesicles of Bacillus megaterium as Enhancers of Ultrasound-Induced Transcriptional Regulation

Gas vesicles (GVs) are large cylindrical gas-filled protein assemblies found in diverse aquatic bacteria that enable their adaptation of buoyancy. GVs have already been used as ultrasound contrasting agents. Here, we investigate GVs derived from Bacillus megaterium, aiming to minimize the number of accessory Gvps within the GV gene cluster and demonstrate the use of GVs as enhancers of acoustic radiation force administered by ultrasound. Three (GvpR, GvpT, and GvpU) out of 11 genes in the cluster were found to be dispensable for functional GV formation, and their omission resulted in narrower GVs. Two essential proteins GvpJ and GvpN were absent from recently determined GV structures, but GvpJ was nevertheless found to be tightly bound to the cylindrical part of GVs in this study. Additionally, the N-terminus of GvpN was observed to play an important role in the formation of mature GVs. The binding of engineered GvpC fromAnabaena flos-aquae to HEK293 cells via integrins enhanced the acoustic force delivered by ultrasound and resulted in an increased Ca2+ influx into cells. Coupling with a synthetic Ca2+-dependent signaling pathway GVs efficiently enhanced cell stimulation by ultrasound, which expands the potentials of noninvasive sonogenetics cell stimulation.

A systematic review of preclinical and clinical transcranial ultrasound neuromodulation and opportunities for functional connectomics

BACKGROUND

Low-intensity transcranial ultrasound has surged forward as a non-invasive and disruptive tool for neuromodulation with applications in basic neuroscience research and the treatment of neurological and psychiatric conditions.

OBJECTIVE

To provide a comprehensive overview and update of preclinical and clinical transcranial low intensity ultrasound for neuromodulation and emphasize the emerging role of functional brain mapping to guide, better understand, and predict responses.

METHODS

A systematic review was conducted by searching the Web of Science and Scopus databases for studies on transcranial ultrasound neuromodulation, both in humans and animals.

RESULTS

187 relevant studies were identified and reviewed, including 116 preclinical and 71 clinical reports with subjects belonging to diverse cohorts. Milestones of ultrasound neuromodulation are described within an overview of the broader landscape. General neural readouts and outcome measures are discussed, potential confounds are noted, and the emerging use of functional magnetic resonance imaging is highlighted.

CONCLUSION

Ultrasound neuromodulation has emerged as a powerful tool to study and treat a range of conditions and its combination with various neural readouts has significantly advanced this platform. In particular, the use of functional magnetic resonance imaging has yielded exciting inferences into ultrasound neuromodulation and has the potential to advance our understanding of brain function, neuromodulatory mechanisms, and ultimately clinical outcomes. It is anticipated that these preclinical and clinical trials are the first of many; that transcranial low intensity focused ultrasound, particularly in combination with functional magnetic resonance imaging, has the potential to enhance treatment for a spectrum of neurological conditions.

The emergence of cancer sono-immunotherapy

Owing to its remarkable ease of use, ultrasound has recently been explored for stimulating or amplifying immune responses during cancer therapy, termed 'sono-immunotherapy'. Ultrasound can cause immunogenic cell death in cancer cells via thermal and nonthermal effects to regulate the tumor microenvironment, thereby priming anticancer immunity; by integrating well-designed biomaterials, novel sono-immunotherapy approaches with augmented efficacy can also be developed. Here, we review the advances in sono-immunotherapy for cancer treatment and summarize existing limitations along with potential trends. We offer emerging insights into this realm, which might prompt breakthroughs and expand its potential applications to other diseases.

Microscale geometrical modulation of PIEZO1 mediated mechanosensing through cytoskeletal redistribution

The microgeometry of the cellular microenvironment profoundly impacts cellular behaviors, yet the link between it and the ubiquitously expressed mechanosensitive ion channel PIEZO1 remains unclear. Herein, we describe a fluorescent micropipette aspiration assay that allows for simultaneous visualization of intracellular calcium dynamics and cytoskeletal architecture in real-time, under varied micropipette geometries. By integrating elastic shell finite element analysis with fluorescent lifetime imaging microscopy and employing PIEZO1-specific transgenic red blood cells and HEK cell lines, we demonstrate a direct correlation between the microscale geometry of aspiration and PIEZO1-mediated calcium signaling. We reveal that increased micropipette tip angles and physical constrictions lead to a significant reorganization of F-actin, accumulation at the aspirated cell neck, and subsequently amplify the tension stress at the dome of the cell to induce more PIEZO1's activity. Disruption of the F-actin network or inhibition of its mobility leads to a notable decline in PIEZO1 mediated calcium influx, underscoring its critical role in cellular mechanosensing amidst geometrical constraints.

Heat-inducible CAR-T overcomes adverse mechanical tumor microenvironment in a 3D bioprinted glioblastoma model

Glioblastoma (GBM) presents a significant therapeutic challenge due to the limited efficacy of existing treatments. Chimeric antigen receptor (CAR) T-cell therapy offers promise, but its potential in solid tumors like GBM is undermined by the physical barrier posed by the extracellular matrix (ECM). To address the inadequacies of traditional 2D cell culture, animal models, and Matrigel-based 3D culture in mimicking the mechanical characteristics of tumor tissues, we employed biomaterials and digital light processing-based 3D bioprinting to fabricate biomimetic tumor models with finely tunable ECM stiffness independent of ECM composition. Our results demonstrated that increased material stiffness markedly impeded CAR-T cell penetration and tumor cell cytotoxicity in GBM models. The 3D bioprinted models enabled us to examine the influence of ECM stiffness on CAR-T cell therapy effectiveness, providing a clinically pertinent evaluation tool for CAR-T cell development in stiff solid tumors. Furthermore, we developed an innovative heat-inducible CAR-T cell therapy, effectively overcoming the challenges posed by the stiff tumor microenvironment.

Sonogenetics-controlled synthetic designer cells for cancer therapy in tumor mouse models

Bacteria-based therapies are powerful strategies for cancer therapy, yet their clinical application is limited by a lack of tunable genetic switches to safely regulate the local expression and release of therapeutic cargoes. Rapid advances in remote-control technologies have enabled precise control of biological processes in time and space. We developed therapeutically active engineered bacteria mediated by a sono-activatable integrated gene circuit based on the thermosensitive transcriptional repressor TlpA39. Through promoter engineering and ribosome binding site screening, we achieved ultrasound (US)-induced protein expression and secretion in engineered bacteria with minimal noise and high induction efficiency. Specifically, delivered either intratumorally or intravenously, engineered bacteria colonizing tumors suppressed tumor growth through US-irradiation-induced release of the apoptotic protein azurin and an immune checkpoint inhibitor, a nanobody targeting programmed death-ligand 1, in different tumor mouse models. Beyond developing safe and high-performance designer bacteria for tumor therapy, our study illustrates a sonogenetics-controlled therapeutic platform that can be harnessed for bacteria-based precision medicine.

Synthetic biology approaches for improving the specificity and efficacy of cancer immunotherapy

Immunotherapy has shown robust efficacy in treating a broad spectrum of hematological and solid cancers. Despite the transformative impact of immunotherapy on cancer treatment, several outstanding challenges remain. These challenges include on-target off-tumor toxicity, systemic toxicity, and the complexity of achieving potent and sustainable therapeutic efficacy. Synthetic biology has emerged as a promising approach to overcome these obstacles, offering innovative tools for engineering living cells with customized functions. This review provides an overview of the current landscape and future prospects of cancer immunotherapy, particularly emphasizing the role of synthetic biology in augmenting its specificity, controllability, and efficacy. We delineate and discuss two principal synthetic biology strategies: those targeting tumor surface antigens with engineered immune cells and those detecting intratumoral disease signatures with engineered gene circuits. This review concludes with a forward-looking perspective on the enduring challenges in cancer immunotherapy and the potential breakthroughs that synthetic biology may contribute to the field.

Photocatalytic manipulation of Ca2+ signaling for regulating cellular and animal behaviors via MOF-enabled H2O2 generation

The in situ generation of H2O2 in cells in response to external stimulation has exceptional advantages in modulating intracellular Ca2+ dynamics, including high controllability and biological safety, but has been rarely explored. Here, we develop photocatalyst-based metal-organic frameworks (DCSA-MOFs) to modulate Ca2+ responses in cells, multicellular spheroids, and organs. By virtue of the efficient photocatalytic oxygen reduction to H2O2 without sacrificial agents, photoexcited DCSA-MOFs can rapidly trigger Ca2+ outflow from the endoplasmic reticulum with single-cell precision in a repeatable and controllable manner, enabling the propagation of intercellular Ca2+ waves (ICW) over long distances in two-dimensional and three-dimensional cell cultures. After photoexcitation, ICWs induced by DCSA-MOFs can activate neural activities in the optical tectum of tadpoles and thighs of spinal frogs, eliciting the corresponding motor behaviors. Our study offers a versatile optical nongenetic modulation technique that enables remote, repeatable, and controlled manipulation of cellular and animal behaviors.

Tension activation of mechanosensitive two-pore domain K+ channels TRAAK, TREK-1, and TREK-2

TRAAK, TREK-1, and TREK-2 are mechanosensitive two-pore domain K+ (K2P) channels that contribute to action potential propagation, sensory transduction, and muscle contraction. While structural and functional studies have led to models that explain their mechanosensitivity, we lack a quantitative understanding of channel activation by membrane tension. Here, we define the tension response of mechanosensitive K2Ps using patch-clamp recording and imaging. All are low-threshold mechanosensitive channels (T10%/50% 0.6-2.7 / 4.4-6.4 mN/m) with distinct response profiles. TRAAK is most sensitive, TREK-1 intermediate, and TREK-2 least sensitive. TRAAK and TREK-1 are activated broadly over a range encompassing nearly all physiologically relevant tensions. TREK-2, in contrast, activates over a narrower range like mechanosensitive channels Piezo1, MscS, and MscL. We further show that low-frequency, low-intensity focused ultrasound increases membrane tension to activate TRAAK and MscS. This work provides insight into tension gating of mechanosensitive K2Ps relevant to understanding their physiological roles and potential applications for ultrasonic neuromodulation.

Towards an ion-channel-centric approach to ultrasound neuromodulation

Ultrasound neuromodulation is a promising technology that could revolutionize study and treatment of brain conditions ranging from mood disorders to Alzheimer's disease and stroke. An understanding of how ultrasound directly modulates specific ion channels could provide a roadmap for targeting specific neurological circuits and achieving desired neurophysiological outcomes. Although experimental challenges make it difficult to unambiguously identify which ion channels are sensitive to ultrasound in vivo, recent progress indicates that there are likely several different ion channels involved, including members of the K2P, Piezo, and TRP channel families. A recent result linking TRPM2 channels in the hypothalamus to induction of torpor by ultrasound in rodents demonstrates the feasibility of targeting a specific ion channel in a specific population of neurons.

Sonogenetics for Monitoring and Modulating Biomolecular Function by Ultrasound

Ultrasound technology, synergistically harnessed with genetic engineering and chemistry concepts, has started to open the gateway to the remarkable realm of sonogenetics-a pioneering paradigm for remotely orchestrating cellular functions at the molecular level. This fusion not only enables precisely targeted imaging and therapeutic interventions, but also advances our comprehension of mechanobiology to unparalleled depths. Sonogenetic tools harness mechanical force within small tissue volumes while preserving the integrity of the surrounding physiological environment, reaching depths of up to tens of centimeters with high spatiotemporal precision. These capabilities circumvent the inherent physical limitations of alternative in vivo control methods such as optogenetics and magnetogenetics. In this review, we first discuss mechanosensitive ion channels, the most commonly utilized sonogenetic mediators, in both mammalian and non-mammalian systems. Subsequently, we provide a comprehensive overview of state-of-the-art sonogenetic approaches that leverage thermal or mechanical features of ultrasonic waves. Additionally, we explore strategies centered around the design of mechanochemically reactive macromolecular systems. Furthermore, we delve into the realm of ultrasound imaging of biomolecular function, encompassing the utilization of gas vesicles and acoustic reporter genes. Finally, we shed light on limitations and challenges of sonogenetics and present a perspective on the future of this promising technology.

Alternating magnetic fields drive stimulation of gene expression via generation of reactive oxygen species

Magnetogenetics represents a method for remote control of cellular function. Previous work suggests that generation of reactive oxygen species (ROS) initiates downstream signaling. Herein, a chemical biology approach was used to elucidate further the mechanism of radio frequency-alternating magnetic field (RF-AMF) stimulation of a TRPV1-ferritin magnetogenetics platform that leads to Ca2+ flux. RF-AMF stimulation of HEK293T cells expressing TRPV1-ferritin resulted in ∼30% and ∼140% increase in intra- and extracellular ROS levels, respectively. Mutations to specific cysteine residues in TRPV1 responsible for ROS sensitivity eliminated RF-AMF driven Ca2+-dependent transcription of secreted embryonic alkaline phosphatase (SEAP). Using a non-tethered (to TRPV1) ferritin also eliminated RF-AMF driven SEAP production, and using specific inhibitors, ROS-activated TRPV1 signaling involves protein kinase C, NADPH oxidase, and the endoplasmic reticulum. These results suggest ferritin-dependent ROS activation of TRPV1 plays a key role in the initiation of magnetogenetics, and provides relevance for potential applications in medicine and biotechnology.

Piezo1 and Its Function in Different Blood Cell Lineages

Mechanosensation is a fundamental function through which cells sense mechanical stimuli by initiating intracellular ion currents. Ion channels play a pivotal role in this process by orchestrating a cascade of events leading to the activation of downstream signaling pathways in response to particular stimuli. Piezo1 is a cation channel that reacts with Ca2+ influx in response to pressure sensation evoked by tension on the cell lipid membrane, originating from cell-cell, cell-matrix, or hydrostatic pressure forces, such as laminar flow and shear stress. The application of such forces takes place in normal physiological processes of the cell, but also in the context of different diseases, where microenvironment stiffness or excessive/irregular hydrostatic pressure dysregulates the normal expression and/or activation of Piezo1. Since Piezo1 is expressed in several blood cell lineages and mutations of the channel have been associated with blood cell disorders, studies have focused on its role in the development and function of blood cells. Here, we review the function of Piezo1 in different blood cell lineages and related diseases, with a focus on megakaryocytes and platelets.

Evidence and therapeutic implications of biomechanically regulated immunosurveillance in cancer and other diseases

Disease progression is usually accompanied by changes in the biochemical composition of cells and tissues and their biophysical properties. For instance, hallmarks of cancer include the stiffening of tissues caused by extracellular matrix remodelling and the softening of individual cancer cells. In this context, accumulating evidence has shown that immune cells sense and respond to mechanical signals from the environment. However, the mechanisms regulating these mechanical aspects of immune surveillance remain partially understood. The growing appreciation for the 'mechano-immunology' field has urged researchers to investigate how immune cells sense and respond to mechanical cues in various disease settings, paving the way for the development of novel engineering strategies that aim at mechanically modulating and potentiating immune cells for enhanced immunotherapies. Recent pioneer developments in this direction have laid the foundations for leveraging 'mechanical immunoengineering' strategies to treat various diseases. This Review first outlines the mechanical changes occurring during pathological progression in several diseases, including cancer, fibrosis and infection. We next highlight the mechanosensitive nature of immune cells and how mechanical forces govern the immune responses in different diseases. Finally, we discuss how targeting the biomechanical features of the disease milieu and immune cells is a promising strategy for manipulating therapeutic outcomes.

Mechanical forces amplify TCR mechanotransduction in T cell activation and function

Adoptive T cell immunotherapies, including engineered T cell receptor (eTCR) and chimeric antigen receptor (CAR) T cell immunotherapies, have shown efficacy in treating a subset of hematologic malignancies, exhibit promise in solid tumors, and have many other potential applications, such as in fibrosis, autoimmunity, and regenerative medicine. While immunoengineering has focused on designing biomaterials to present biochemical cues to manipulate T cells ex vivo and in vivo, mechanical cues that regulate their biology have been largely underappreciated. This review highlights the contributions of mechanical force to several receptor-ligand interactions critical to T cell function, with central focus on the TCR-peptide-loaded major histocompatibility complex (pMHC). We then emphasize the role of mechanical forces in (i) allosteric strengthening of the TCR-pMHC interaction in amplifying ligand discrimination during T cell antigen recognition prior to activation and (ii) T cell interactions with the extracellular matrix. We then describe approaches to design eTCRs, CARs, and biomaterials to exploit TCR mechanosensitivity in order to potentiate T cell manufacturing and function in adoptive T cell immunotherapy.