Search Results (35)

Osteosarcoma (OS), the most common primary malignant bone tumor, arises in highly mechanosensitive tissue and exhibits marked heterogeneity and resistance to conventional therapies. While molecular drivers have been extensively characterized, the role of mechanical stimuli in OS progression remains underexplored. Here, we identify the transient receptor potential vanilloid 1 (TRPV1) channel as a key regulator of mechanotransduction and drug responsiveness in OS cells. Using uniaxial cyclic stretch, we show that aggressive U-2 OS cells undergo TRPV1-dependent perpendicular reorientation, unlike the inert SAOS-2 cells. Confocal microscopy, immunohistochemistry, and atomic force microscopy reveal that nanomolar concentrations of capsaicin—a well-characterized TRPV1 agonist—chemically mimic this mechanical phenotype, altering metastatic traits including adhesion, edge architecture, migration, nuclear-to-cytoplasmic ratio, and sensitivity to doxorubicin and cisplatin. TRPV1 activation, whether mechanical or chemical, induces subtype-specific effects absent in healthy hFOB osteoblasts. Notably, it differentially regulates nuclear localization of the proto-oncogene Src in U-2 OS versus SAOS-2 cells. Corresponding changes in Src and acetylated histone H3 (acH3) levels support a role for TRPV1 in modulating the Src–acH3 mechanosignaling axis. These effects are tumor-specific, positioning TRPV1 as a mechanosensitive signaling hub that integrates mechanical and chemical cues to drive epigenetic remodeling and phenotypic plasticity in OS, with potential as a therapeutic target in aggressive, drug-resistant subtypes Full article

Orthodontic tooth movement (OTM) is accompanied by sterile inflammation, a necessary biological process that facilitates tooth displacement but also contributes to adverse effects, including hyalinization and orthodontically induced external apical root resorption (OEARR). Despite advancements in orthodontic therapies, the inflammatory response—regulated by dynamic interactions between tissue-specific cells and their molecular mediators—remains a critical factor influencing treatment outcomes. This review summarizes the current understanding of the cellular and molecular mechanisms underlying OTM, with a focus on how these insights can support the development of targeted therapeutic strategies. These include cell- and molecule-based therapies, biomaterial-mediated delivery systems, and applications of artificial intelligence (AI). Notably, AI offers promising opportunities for modeling and simulating biological responses, enabling the optimization of individualized treatment planning. We further discuss current clinical practices and highlight emerging experimental findings, with an emphasis on unresolved research questions pivotal to improving therapeutic efficacy and reducing complications such as OEARR. This comprehensive overview aims to inform future directions in orthodontics by integrating mechanistic knowledge with technological innovation. Full article

Mechanotransduction, also referred to as mechano-signal transduction, is a biophysical process wherein cells perceive and respond to mechanical stimuli by converting them into biochemical signals that initiate specific cellular responses. This mechanism is fundamental to the development and growth, and proper functioning of mechanically active tissues, such as the diaphragm—a respiratory muscle vital for breathing in mammals. In vivo, the diaphragm is subjected to transdiaphragmatic pressure, and therefore, its muscle fibers are subjected to mechanical forces not only in the direction of the muscle fibers but also in the direction transverse to the fibers. Previous research conducted in our laboratory uncovered that stretching the diaphragm in either the longitudinal or transverse direction activates distinct mechanotransduction pathways. This indicates that signaling pathways in the diaphragm muscle are regulated in an anisotropic manner. In this review paper, we discussed the underlying mechanisms that regulate the anisotropic signaling pathways in the diaphragmatic muscle, emphasizing the mechanical role of cytoskeletal proteins in this context. Furthermore, we explored the regulatory mechanisms governing mechanosensitive gene transcription, including microRNAs (mechanomiRs), within the diaphragm muscle. Finally, we examined potential links between anisotropic signaling in the diaphragm muscle and various skeletal muscle disorders. Full article

Mechanical stresses affect a variety of cellular events in relation to the frequency, magnitude, and duration of the stimuli applied. Embryonic stem cell (ESC)-derived embryoid bodies (EBs) are pluripotent stem cell aggregates and comprise all somatic cells. Numerous studies have highlighted the effects of mechanosignals on stem cells, whereas their impact on EBs has been barely investigated. Here, we examined how cyclic tensile stress affects the behavior of EBs to differentiate into mineralized osteocytes by applying 2% elongation at 0.5 Hz frequency for 1 h once or 1 h every other day for 5 or 14 days in osteogenic medium. EBs that expressed undifferentiated markers, Oct4 and Sox2, were differentiated into mineralized cells, along with the accumulation of runt-related transcription factor 2 (RUNX2) and β-catenin in osteogenic medium. The application of tensile force inhibited EB’ mineralization via the downregulation of bone sialoprotein, osteocalcin, osterix, and RUNX2. While the transfection with si-β-catenin did not affect the osteogenic potency of EBs at a significant level, treatment with 10 μM of PD98059, but not of SP600125 or SB203580, diminished the mineralization of EBs and the expression of RUNX2 and RUNX2-regulated osteoblastic genes. The level of phosphorylated extracellular signal-regulated kinase-1 (p-ERK1) rather than p-ERK2 was more apparently diminished in tension-applied EBs. The transfection with si-ERK1, but not with si-ERK2, suppressed the mineralization of osteogenic medium-supplied EBs and the expression of osteoblast-specific genes. Collectively, this study demonstrates that tensile stress inhibits osteogenic potency of EBs by downregulating ERK1-mediated signaling and osteogenic gene expression. Full article

Bone is a highly mechanosensitive tissue, where mechanical signaling plays a central role in maintaining skeletal homeostasis. Mechanotransduction regulates the balance between bone formation and resorption through coordinated interactions among bone cells. Key mechanosensing structures—including the extracellular/pericellular matrix (ECM/PCM), integrins, ion channels, connexins, and primary cilia, translate mechanical cues into biochemical signals that drive bone adaptation. Disruptions in mechanotransduction are increasingly recognized as an important factor in osteoporosis. Under pathological conditions, impaired mechanical signaling reduces bone formation and accelerates bone resorption, leading to skeletal fragility. Defects in mechanotransduction disrupt key pathways involved in bone metabolism, further exacerbating bone loss. Therefore, targeting mechanotransduction presents a promising pharmacological strategy for osteoporosis treatment. Recent advances have focused on developing drugs that enhance bone mechanosensitivity by modulating key mechanotransduction pathways, including integrins, ion channels, connexins, and Wnt signaling. A deeper understanding of mechanosignaling mechanisms may pave the way for novel therapeutic approaches aimed at restoring bone mass, mechanical integrity, and mechanosensitive bone adaptation. Full article

Liver fibrosis, a consequence of chronic liver injury, represents a major global health burden and is the leading cause of liver failure, morbidity, and mortality. The pathological hallmark of this condition is excessive extracellular matrix deposition, driven primarily by integrin-mediated mechanotransduction. Integrins, transmembrane heterodimeric proteins that serve as primary ECM receptors, orchestrate complex mechanosignaling networks that regulate the activation, differentiation, and proliferation of hepatic stellate cells and other ECM-secreting myofibroblasts. These mechanical signals create self-reinforcing feedback loops that perpetuate the fibrotic response. Recent advances have provided insight into the roles of specific integrin subtypes in liver fibrosis and revealed their regulation of key downstream effectors—including transforming growth factor beta, focal adhesion kinase, RhoA/Rho-associated, coiled-coil containing protein kinase, and the mechanosensitive Hippo pathway. Understanding these mechanotransduction networks has opened new therapeutic possibilities through pharmacological manipulation of integrin-dependent signaling. Full article

Mechano-signal transduction is a process in which cells perceive extracellular mechanical signals, convert them into intracellular biochemical signals, and produce a response. Integrins are cell surface receptors that sense the extracellular mechanical cues and bind to the extracellular matrix (ECM). This binding induces integrin clustering and activation. Cytoplasmic tails of activated integrins interact and induce cytoskeleton tensions via several adaptor proteins. Integrins monitor extracellular stiffness via cytoskeleton tensions and modulate ECM stiffness via downstream signaling pathways regulating the expression of genes of ECM components. Integrin-mediated mechano-transduction is very crucial for the cell as it regulates the cell physiology both in normal and diseased conditions according to extracellular mechanical cues. It regulates cell proliferation, survival, and migration. Abnormal mechanical cues such as extreme and prolonged mechanical stress result in pathological conditions including fibrosis, cancers, skin, and autoimmune disorders. This paper aims to explore the role of integrins and their associated proteins in mechano-signal transduction. It highlights the integrins and their associated proteins as targets for therapy development. Furthermore, it also presents the challenges to the targeted drug development, which can be drug resistance and cytotoxicity. It is concluded in this paper that research on integrin-mediated mechano-signal transduction and its relationship with cell physiology and pathologies will be an important step towards the development of effective therapies. Full article

Mechanical signals from the extracellular matrix are crucial in guiding cellular behavior. Two-dimensional hydrogel substrates for cell cultures serve as exceptional tools for mechanobiology studies because they mimic the biomechanical and adhesive characteristics of natural environments. However, the interdisciplinary knowledge required to synthetize and manipulate these biomaterials typically restricts their widespread use in biological laboratories, which may not have the material science expertise or specialized instrumentation. To address this, we propose a scalable method that requires minimal setup to produce 2D hydrogel substrates with independent modulation of the rigidity and adhesiveness within the range typical of natural tissues. In this method, norbornene-terminated 8-arm polyethylene glycol is stoichiometrically functionalized with RGD peptides and crosslinked with a di-cysteine terminated peptide via a thiol–ene click reaction. Since the synthesis process significantly influences the final properties of the hydrogels, we provide a detailed description of the chemical procedure to ensure reproducibility and high throughput results. We demonstrate examples of cell mechanosignaling by monitoring the activation state of the mechanoeffector proteins YAP/TAZ. This method effectively dissects the influence of biophysical and adhesive cues on cell behavior. We believe that our procedure will be easily adopted by other cell biology laboratories, improving its accessibility and practical application. Full article

In the last decade, a group of Ca²⁺ channels called Piezo were discovered, demonstrating a decisive role in the cellular response to mechanical stimuli and being essential in the biological behavior of cells regarding the extracellular compartment. Several investigations have suggested a potential role in carcinogenesis, with a tumor suppressor role in some cases but increased expression in several high-grade neoplasms. Regarding Piezo2 expression in mammary gland neoplasms, a protective role for Piezo2 was initially suggested, but a subsequent study demonstrated a relationship between Piezo2 expression and the highly aggressive triple-negative phenotype of breast carcinoma. A cohort of 125 patients with clinical follow-up was chosen to study Piezo2 expression and clarify its clinical implications using the same immunohistochemical evaluation performed for other breast carcinoma parameters. Fisher’s exact test was chosen to identify potential relationships between the different variables. A significant association was found with the Ki67 proliferation index, but not with mitoses. The tendency of most proliferative tumors was to have an increased score for Piezo2. A similar association was found between Piezo2 expression and perineural invasion. Full article

Diet-induced obesity (DIO) promotes pancreatic ductal adenocarcinoma (PDAC) in mice expressing KRasG12D in the pancreas (KC mice), but the precise mechanisms remain unclear. Here, we performed multiplex quantitative proteomic and phosphoproteomic analysis by liquid chromatography–tandem mass spectrometry and further bioinformatic and spatial analysis of pancreas tissues from control-fed versus DIO KC mice after 3, 6, and 9 months. Normal pancreatic parenchyma and associated proteins were steadily eliminated and the novel proteins, phosphoproteins, and signaling pathways associated with PDAC tumorigenesis increased until 6 months, when most males exhibited cancer, but females did not. Differentially expressed proteins and phosphoproteins induced by DIO revealed the crucial functional role of matrisomal proteins, which implies the roles of upstream regulation by TGFβ, extracellular matrix-receptor signaling to downstream PI3K-Akt-mTOR-, MAPK-, and Yap/Taz activation, and crucial effects in the tumor microenvironment such as metabolic alterations and signaling crosstalk between immune cells, cancer-associated fibroblasts (CAFs), and tumor cells. Staining tissues from KC mice localized the expression of several prognostic PDAC biomarkers and elucidated tumorigenic features, such as robust macrophage infiltration, acinar–ductal metaplasia, mucinous PanIN, distinct nonmucinous atypical flat lesions (AFLs) surrounded by smooth muscle actin-positive CAFs, invasive tumors with epithelial–mesenchymal transition arising close to AFLs, and expanding deserted areas by 9 months. We next used Nanostring GeoMX to characterize the early spatial distribution of specific immune cell subtypes in distinct normal, stromal, and PanIN areas. Taken together, these data richly contextualize DIO promotion of Kras-driven PDAC tumorigenesis and provide many novel insights into the signaling pathways and processes involved. Full article

The pericellular matrix (PCM) is a specialized extracellular matrix that surrounds cells. Interactions with the PCM enable the cells to sense and respond to mechanical signals, triggering a proper adaptive response. Collagen VI is a component of muscle and tendon PCM. Mutations in collagen VI genes cause a distinctive group of inherited skeletal muscle diseases, and Ullrich congenital muscular dystrophy (UCMD) is the most severe form. In addition to muscle weakness, UCMD patients show structural and functional changes of the tendon PCM. In this study, we investigated whether PCM alterations due to collagen VI mutations affect the response of tendon fibroblasts to mechanical stimulation. By taking advantage of human tendon cultures obtained from unaffected donors and from UCMD patients, we analyzed the morphological and functional properties of cellular mechanosensors. We found that the length of the primary cilia of UCMD cells was longer than that of controls. Unlike controls, in UCMD cells, both cilia prevalence and length were not recovered after mechanical stimulation. Accordingly, under the same experimental conditions, the activation of the Hedgehog signaling pathway, which is related to cilia activity, was impaired in UCMD cells. Finally, UCMD tendon cells exposed to mechanical stimuli showed altered focal adhesions, as well as impaired activation of Akt, ERK1/2, p38MAPK, and mechanoresponsive genes downstream of YAP. By exploring the response to mechanical stimulation, for the first time, our findings uncover novel unreported mechanistic aspects of the physiopathology of UCMD-derived tendon fibroblasts and point at a role for collagen VI in the modulation of mechanotransduction in tendons. Full article

PIEZO1 plays a crucial role in the human body as a mechanosensory ion channel. It has been demonstrated that PIEZO1 is important in tissue development and regulating many essential physiological processes. Studies have suggested that the PIEZO1 ion channel plays a role in invasion and progression in cancer; elevated levels of PIEZO1 have been correlated with increased migration in breast cancer cells, chemo-resistance and invasion in gastric cancer cells, and increased invasion of osteosarcoma cells. In addition, high PIEZO1 expression levels were correlated with a worse prognosis in glioma patients. On the other hand, studies in lung cancer have attributed high PIEZO1 levels to better patient outcomes. However, the clinical impact of PIEZO1 in breast cancer is not well characterized. Therefore, our goal was to determine the clinical relevance of PIEZO1 in breast cancer. An analysis of breast cancer data from The Cancer Genome Atlas (TCGA) was conducted to investigate PIEZO1 expression levels and correlation to survival, followed by validation in an independent dataset, GSE3494. We also performed gene set enrichment analysis (GSEA) and pathway enrichment analysis. We also analyzed the immune cell composition in breast tumors from TCGA through a CIBERSORT algorithm. Our results demonstrated that the PIEZO1 expression levels are higher in hormone-receptor (HR)-negative than in HR-positive cohorts. High PIEZO1 expression is correlated with a significant decrease in survival in HR-negative cohorts, especially in triple-negative breast cancer (TNBC), suggesting that PIEZO1 could be utilized as a prognostic biomarker in HR-negative breast cancer. GSEA showed that various signaling pathways associated with more invasive phenotypes and resistance to treatments, including epithelial–mesenchymal transition (EMT), hypoxia, and multiple signaling pathways, are enriched in high-PIEZO1 HR-negative tumors. Our results also demonstrated a decrease in CD8+ and CD4+ T cell infiltration in high-PIEZO1 HR-negative tumors. Further investigations are necessary to elucidate the mechanistic roles of PIEZO1 in HR-negative breast cancer. Full article

Osteoporosis and degenerative endocrine diseases are some of the major causes of disability in the elderly. The feedback loop in the endocrine system works to control the release of hormones and maintain the homeostasis of metabolism, thereby regulating the function of target organs. The breakdown of this feedback loop results in various endocrine and metabolic disorders, such as osteoporosis, type II diabetes, hyperlipidemia, etc. The direct regulation of redox homeostasis is one of the most attractive strategies to redress the imbalance of the feedback loop. The biophysical regulation of redox homeostasis can be achieved through engineered dynamic hydrogel niches, with which cellular mechanics and redox homeostasis are intrinsically connected. Mechanotransduction-dependent redox signaling is initiated by cell surface protein assemblies, cadherins for cell–cell junctions, and integrins for cell–ECM interactions. In this review, we focused on the biophysical regulation of redox homeostasis via the tunable cell–ECM interactions in the engineered dynamic hydrogel niches. We elucidate processes from the rational design of the hydrogel matrix to the mechano-signaling initiation and then to the redox response of the encapsulated cells. We also gave a comprehensive summary of the current biomedical applications of this strategy in several degenerative endocrine disease models. Full article

In preparing space and microgravity experiments, the utilization of ground-based facilities is common for initial experiments and feasibility studies. One approach to simulating microgravity conditions on Earth is to employ a random positioning machine (RPM) as a rotary bioreactor. Combined with a suitable low-mass model system, such as cell cultures, these devices simulating microgravity have been shown to produce results similar to those obtained in a space experiment under real microgravity conditions. One of these effects observed under real and simulated microgravity is the formation of spheroids from 2D adherent cancer cell cultures. Since real microgravity cannot be generated in a laboratory on Earth, we aimed to determine which forces lead to the detachment of individual FTC-133 thyroid cancer cells and the formation of tumor spheroids during culture with exposure to random positioning modes. To this end, we subdivided the RPM motion into different static and dynamic orientations of cell culture flasks. We focused on the molecular activation of the mechanosignaling pathways previously associated with spheroid formation in microgravity. Our results suggest that RPM-induced spheroid formation is a two-step process. First, the cells need to be detached, induced by the cell culture flask’s rotation and the subsequent fluid flow, as well as the presence of air bubbles. Once the cells are detached and in suspension, random positioning prevents sedimentation, allowing 3D aggregates to form. In a comparative shear stress experiment using defined fluid flow paradigms, transcriptional responses were triggered comparable to exposure of FTC-133 cells to the RPM. In summary, the RPM serves as a simulator of microgravity by randomizing the impact of Earth’s gravity vector especially for suspension (i.e., detached) cells. Simultaneously, it simulates physiological shear forces on the adherent cell layer. The RPM thus offers a unique combination of environmental conditions for in vitro cancer research. Full article

Endothelial cells lining blood vessels are essential for maintaining vascular homeostasis and mediate several pathological and physiological processes. Mechanical stresses generated by blood flow and other biomechanical factors significantly affect endothelial cell activity. Here, we review how mechanical stresses, both in situ and in vitro, affect endothelial cells. We review the basic principles underlying the cellular response to mechanical stresses. We also consider the implications of these findings for understanding the mechanisms of mechanotransducer and mechano-signal transduction systems by cytoskeletal components. Full article