Mechanobiology in Medicine最新文献

Bone and immune cells typically inhabit the same microenvironment and engage in mutual interactions to collectively execute the functions of the “osteoimmune system.” Establishing a harmonized and enduring osteoimmune system significantly enhances bone regeneration, necessitating the maintenance of bone and immune homeostasis. Recently, mechanobiology has garnered increasing interest in bone tissue engineering, with matrix stiffness emerging as a crucial parameter that has been extensively investigated. The effect of matrix stiffness on bone homeostasis remains relatively clear. Soft substrates tend to significantly affect the chondrogenic differentiation of bone marrow mesenchymal stem cells, whereas increasing matrix stiffness is advantageous for osteogenic differentiation. Increased stiffness increases osteoclast differentiation and activity. Additionally, there is increasing emphasis on immune homeostasis, which necessitates dynamic communication between immune cells. Immune cells are crucial in initiating bone regeneration and driving early inflammatory responses. Functional changes induced by matrix stiffness are pivotal for determining the outcomes of engineered tissue mimics. However, inconsistent and incomparable findings regarding the responses of different immune cells to matrix stiffness can be perplexing owing to variations in the stiffness range, measurement methods, and other factors. Therefore, this study aimed to provide a comprehensive review of the specific effects of matrix stiffness on diverse immune cells, with a particular focus on its implications for bone regeneration, which would offer theoretical insights into the treatment of large segmental bony defects and assist in the clinical development of new engineering strategies.

The gastrointestinal (GI) tract's primary role is food digestion, relying on coordinated fluid secretion and bowel movements triggered by mechanosensation. Enteroendocrine cells (EECs) are specialized mechanosensitive cells that convert mechanical forces into electrochemical signals, culminating in serotonin release to regulate GI motility. Despite their pivotal role, knowledge of EEC mechanical properties has been lacking due to their rarity and limited accessibility. In this brief report, we present the first single-cell mechanical characterization of human ECCs isolated from healthy intestinal organoids. Using single-cell optical tweezers, we measured EEC stiffness profiles at the physiological temperature and investigated changes following tryptophan metabolism inhibition. Our findings not only shed light on EEC mechanics but also highlight the potential of adult stem cell-derived organoids for studying these elusive cells.

Mechanotransduction is essential for cell fate and behavior, and F-actin plays a key role in the generation and transmission of molecular forces. A recent study published in Nature Communication presented a novel high-precision molecular tension measurement method using a Förster resonance energy transfer–based tension sensor with separated load-bearing function within distinct F-actin structures, and demonstrated that cellular mechanical anisotropy depends on cell shape, loading direction, and magnitude.

Osteoarthritis (OA) is a progressive degenerative joint sickness related with mechanics, obesity, ageing, etc., mainly characterized by cartilage degeneration, subchondral bone damage and synovium inflammation. Coordinated mechanical absorption and conduction of the joint play significant roles in the prevalence and development of OA. Subchondral bone is generally considered a load-burdening tissue where mechanosensitive cells are resident, including osteocytes, osteoblast lineage cells, and osteoclast lineage cells (especially less concerned in mechanical studies). Mechano-signaling imbalances affect complicated cellular events and disorders of subchondral bone homeostasis. This paper will focus on the significance of mechanical force as the pathogenesis, involvement of various mechanical force patterns in mechanosensitive cells, and mechanobiology research of loading devices in vitro and in vivo, which are further discussed. Additionally, various mechanosensing structures (e.g., transient receptor potential channels, gap junctions, primary cilia, podosome-associated complexes, extracellular vesicles) and mechanotransduction signaling pathways (e.g., Ca²⁺ signaling, Wnt/β-catenin, RhoA GTPase, focal adhesion kinase, cotranscriptional activators YAP/TAZ) in mechanosensitive bone cells. Finally, we highlight potential targets for improving mechanoprotection in the treatment of OA. These advances furnish an integration of mechanical regulation of subchondral bone homeostasis, as well as OA therapeutic approaches by modulating mechanical homeostasis.

A recent study published in Nature Communications introduces a novel mechanically-mediated reaction involving ZnO nanoparticles that autonomously react, forming Zn/S mineral microrods within an organogel. These microrods selectively reinforce synthetic polymer composites, offering a unique approach to material strengthening. The method provides a distinctive pathway for mechanical mineralization in composite materials.

Type 1 hypersensitivity involves an exaggerated immune reaction triggered by allergen exposure, leading to rapid release of inflammatory mediators. Meanwhile, mechanobiology explores how physical forces influence cellular processes, and recent research underscores its relevance in allergic reactions. This review provides a concise overview of Type 1 hypersensitivity, highlighting the pivotal role of mast cells and immunoglobulin E (IgE) antibodies in orchestrating allergic reactions. Recognizing the dynamic nature of cellular responses in allergies, this study subsequently delves into the emerging field of mechanobiology and its significance in understanding the mechanical forces governing immune cell behavior. Furthermore, molecular forces during mast cell activation and degranulation are explored, elucidating the mechanical aspects of IgE binding and cytoskeletal rearrangements. Next, we discuss the intricate interplay between immune cells and the extracellular matrix, emphasizing the impact of matrix stiffness on cellular responses. Additionally, we examine key mechanosensitive signaling pathways, including the mitogen-activated protein kinase (MAPK) pathway, Rho guanosine triphosphatase (GTPase) and integrin-mediated focal adhesion signaling, shedding light on their contributions to hypersensitivity reactions. This interplay of mechanobiology and Type 1 hypersensitivity provides insights into potential therapeutic targets and biomarkers, paving the way for better clinical management of Type 1 hypersensitivity reactions.

Mechanical models offer a quantitative framework for understanding scientific problems, predicting novel phenomena, and guiding experimental designs. Over the past few decades, the emerging field of cellular mechanobiology has greatly benefited from the substantial contributions of new theoretical tools grounded in mechanical models. Within the expansive realm of mechanobiology, the investigation of how cells sense and respond to their microenvironment has become a prominent research focus. There is a growing acknowledgment that cells mechanically interact with their external surroundings through an integrated machinery encompassing the cell membrane, cytoskeleton, and nucleus. This review provides a comprehensive overview of mechanical models addressing three pivotal components crucial for force transmission within cells, extending from mechanosensitive receptors on the cell membrane to the actomyosin cytoskeleton and ultimately to the nucleus. We present the existing numerical relationships that form the basis for understanding the structures, mechanical properties, and functions of these components. Additionally, we underscore the significance of developing mechanical models in advancing cellular mechanobiology and propose potential directions for the evolution of these models.

Neural stem cells in vivo receive information from biochemical and biophysical cues of their microenvironment that affect their survival, proliferation and differentiation toward specific lineages. Recapitulation of these conditions in vitro is better achieved in 3D cell cultures. Especially the cells that grow in scaffold-dependent 3D cultures establish more complex cell–cell and cell–material interactions enabling the study of the various signaling pathways. The biochemical signaling from growth factors and hormones has been extensively studied over the years. More recently cumulative evidence demonstrates that cell sensing and response to mechanical stimuli is mediated through mechanotransduction pathways. Although individual signaling pathways activated by biochemical or mechanical cues in cells are well-studied, synergistic or antagonistic effects among them need further research to be fully understood. The understanding of the alteration of the cell behavior due to a microenvironmental cues would be greatly enhanced by the study of key elements that lie in the convergence of biochemical and mechanical pathways. Here we analyzed the effect of the substrate topography on the nerve growth factor (NGF) induced differentiation of PC12 cells. Our results showed that the topography interferes with NGF-induced neuronal differentiation and this is reflected in the reduced activation of the integrin-mediated mechanotransduction.

Accumulating evidence strongly suggests that cell chirality plays a pivotal role in driving left-right (LR) symmetry breaking, a widespread phenomenon in living organisms. Whole embryos and excised organs have historically been employed to investigate LR symmetry breaking and have yielded exciting findings. In recent years, in vitro engineered platforms have emerged as powerful tools to reveal cellular chiral biases and led to uncovering molecular and biophysical insights into chiral morphogenesis, including the significant role of the actin cytoskeleton. Establishing a link between observed in vivo tissue chiral morphogenesis and the determined chiral bias of cells in vitro has become increasingly important. In this regard, computational mathematical models hold immense value as they can explain and predict tissue morphogenic behavior based on the chiral biases of individual cells. Here, we present the formulations and discoveries achieved using various computational models spanning different biological scales, from the molecular and cellular levels to tissue and organ levels. Furthermore, we offer insights into future directions and the role of such models in advancing the study of asymmetric cellular mechanobiology.

Radiation therapy is one of the most effective therapeutic modalities for tumors. The changes in matrix stiffness of tumors and associated tissues are important consequences of side effects after radiotherapy. They are documented to induce the radio-resistance of cancer cells and promote the recurrence and metastasis of tumors, resulting in poor patient prognosis. Identifying the relationship between radiation and matrix stiffness is beneficial to optimize clinical treatment schemes and ultimately improve the patient prognosis. Herein, this review includes knowledge regarding the specific cellular, molecular processes and relevant clinical factors of the changes in matrix stiffness of tumors or associated tissues induced by radiation. The effects of altered matrix stiffness on the behaviors of cancer cells and associated normal cells are further detailed. It also reviews literatures to elucidate the mechanical signal transduction mechanism in radiotherapy and proposes some strategies to enhance the efficacy of radiotherapy based on matrix mechanics.