Piezo1-ERK1/2-YAP Signaling Cascade Regulates the Proliferation of Urine-derived Stem Cells on Collagen Gels

Piezo1 Is Related to the Enamel Matrix Formation in Mouse Tooth Germ Development

Cellular responses to mechanical stimulation are involved in tissue development and the maintenance of biological functions. Teeth function as receptors for mastication and occlusal pressure. During tooth development, the tooth germ begins with an invagination of the epithelium, and its morphology matures through dynamic interactions between epithelial cells and mesenchymal cells, suggesting that mechanosensors may play an important role in this process. We analyzed the expression and function of Piezo1, a mechanically activated ion channel, during tooth development and clarified the involvement of Piezo1 in tooth morphogenesis. The expression of Piezo1 was observed in both the enamel organ and the surrounding mesenchymal cells at the early stage and in the ameloblasts and odontoblasts during enamel and dentin matrix formation. Yoda1, a Piezo1 activator, inhibited cell proliferation in mouse dental epithelial (mDE6) cells and E15 tooth germs, and suppressed cell migration in mDE6 cells. Meanwhile, GsMTx4, a Piezo1 inactivator, showed opposite results. Furthermore, in the organ culture of E15 tooth germs, the activation and inactivation of Piezo1 were found to affect the expression of ameloblast differentiation marker genes and control the arrangement of ameloblasts. Interestingly, the expression of E-cadherin was reduced in the cell membrane of ameloblasts at the cusp in the GsMTx4-treated tooth germs of organ culture, and enamel formation was significantly decreased. Yoda1-treated mDE6 cells showed upregulated E-cadherin expression, which was downregulated by calpain inhibitor. These findings suggest that Piezo1 may be involved in tooth morphogenesis during ameloblast development by playing an essential role in cell proliferation, migration, arrangement, differentiation, and mineralization.

Matrix stiffening induces hepatocyte functional impairment and DNA damage via the Piezo1‒ERK1/2 signaling pathway

Hepatocytes are the primary functional cells in the liver, and the malignant transformation of hepatocytes significantly contributes to hepatocellular carcinoma (HCC) progression. Liver fibrosis and cirrhosis caused by extracellular matrix (ECM) remodeling during liver lesions is a pivotal driver of HCC. However, the impact of matrix stiffness on hepatocytes and the underlying molecular mechanisms are not fully understood. Herein, using gelatin/sodium alginate hydrogels with different stiffnesses to simulate the change of matrix stiffness during liver lesions, we found that matrix stiffening leads to a notable decrease in the expression of hepatocyte nuclear factor 4α (HNF4α) and functional hepatocyte genes and a significant increase in the expression of interleukin 6 (IL‒6) in human hepatocyte line L‒02 cells, indicating obvious damage of hepatocyte function. In addition, matrix stiffening causes extensive DNA damage to L‒02 cells. Mechanistically, matrix stiffening upregulates piezo‒type mechanosensitive ion channel component 1 (Piezo1) expression and activates extracellular signal‒regulated kinase 1/2 (ERK1/2) signaling. Piezo1 knockdown suppresses matrix stiffening‒induced functional impairment and DNA damage in L‒02 cells. Moreover, Piezo1 knockdown blocks matrix stiffening‒activated ERK1/2 signaling in L‒02 cells. U0126 (a selective inhibitor of ERK1/2 activation) treatment could rescue matrix stiffening‒induced functional impairment and DNA damage. Taken together, these findings demonstrate that matrix stiffening induces functional impairment and DNA damage in L‒02 cells via the Piezo1‒ERK1/2 signaling pathway, which provides evidence for a better understanding of the hepatocyte function damage caused by tissue mechanical microenvironment change in liver diseases and the mechanotransduction in this process.

Pleiotropic physiological functions of Piezo1 in human body and its effect on malignant behavior of tumors

Mechanosensitive ion channel protein 1 (Piezo1) is a large homotrimeric membrane protein. Piezo1 has various effects and plays an important and irreplaceable role in the maintenance of human life activities and homeostasis of the internal environment. In addition, recent studies have shown that Piezo1 plays a vital role in tumorigenesis, progression, malignancy and clinical prognosis. Piezo1 is involved in regulating the malignant behaviors of a variety of tumors, including cellular metabolic reprogramming, unlimited proliferation, inhibition of apoptosis, maintenance of stemness, angiogenesis, invasion and metastasis. Moreover, Piezo1 regulates tumor progression by affecting the recruitment, activation, and differentiation of multiple immune cells. Therefore, Piezo1 has excellent potential as an anti-tumor target. The article reviews the diverse physiological functions of Piezo1 in the human body and its major cellular pathways during disease development, and describes in detail the specific mechanisms by which Piezo1 affects the malignant behavior of tumors and its recent progress as a new target for tumor therapy, providing new perspectives for exploring more potential effects on physiological functions and its application in tumor therapy.

Mechanochemical coupling of MGF mediates periodontal regeneration

Clinical evidence shows that the mechanical stimulation obtained from occlusion could enhance periodontal ligament (PDL) remodeling. Mechano-growth factor (MGF) is a growth factor produced specifically following mechanical stimulus Here, we aim to investigate the mechanical enhancement potential and mechanism of the MGF in PDL regeneration. In vivo study found that MGF produced from the PDL under occlusion force could strongly enhance PDL remodeling. In vitro experiments and mathematical modeling further confirmed the mechanical enhancement effect of MGF for PDLSC differentiation toward fibroblasts. A mechanochemical coupling effect of MGF mediated the enhancement of mechanical effect, which was modulated by Fyn-FAK kinases signaling and subsequent MAPK pathway. Finally, enhanced PDL regeneration under the mechanochemical coupling of MGF and occlusal force was verified in vivo. There exists an additive mechanical effect of MGF mediated by Fyn-FAK crosstalk and subsequent ERK1/2 and p38 phosphorylation, which could be developed as an MGF-centered adjuvant treatment to optimize PDL remodeling, especially for patients with weakened bite force or destroyed periodontium.