The sense of mechanical stimuli (e.g. force or deformation) in the environment underlies several important physiological processes, for example the perception of sound, touch, pain and acceleration. The key step in mechanosensation is to convert the extracellular mechanical stimuli into cellular electrical or chemical signals. This process is termed as mechanotransduction. Based on mechanical and electrophysiological measurements, "Gating-Spring" theory was proposed as a general model to describe the cell biological mechanism of mechanotransduction. However, despite efforts made in several model organisms, the molecular basis of the "Gating-Spring" model remains elusive. In recent years, several key progresses have been made using the mechanoreceptors of Drosophila melanogaster as the models. This article introduces the "Gating-Spring" theory and reviews the recent research progresses on the fly mechanotransduction.
Animals ; Drosophila melanogaster ; Mechanoreceptors ; Mechanotransduction, Cellular

Mechanical signal transduction are crucial for chondrocyte in response to mechanical cues during the growth, development and osteoarthritis (OA) of articular cartilage. Extracellular matrix (ECM) turnover regulates the matrix mechanical microenvironment of chondrocytes. Thus, understanding the mechanotransduction mechanisms during chondrocyte sensing the matrix mechanical microenvironment can develop effective targeted therapy for OA. In recent decades, growing evidences are rapidly advancing our understanding of the mechanical force-dependent cartilage remodeling and injury responses mediated by TRPV4 and PIEZOs. In this review, we highlighted the mechanosensing mechanism mediated by TRPV4 and PIEZOs during chondrocytes sensing mechanical microenvironment of the ECM. Additionally, the latest progress in the regulation of OA by inflammatory signals mediated by TRPV4 and PIEZOs was also introduced. These recent insights provide the potential mechanotheraputic strategies to target these channels and prevent cartilage degeneration associated with OA. This review will shed light on the pathogenesis of articular cartilage, searching clinical targeted therapies, and designing cell-induced biomaterials.
Chondrocytes ; TRPV Cation Channels ; Mechanotransduction, Cellular ; Biocompatible Materials ; Cartilage, Articular

This paper discusses the law of atrial electrical activity propagation (the timing of signal and the conduction velocity) under the sinus rhythm before and after AF caused by high-frequency electrical stimulation. The paper analyzes how different doses of acetylcholine affect the conductivity of the atrial cells of dogs. This result can also help the diagnoses and treatment of human's AF.
Acetylcholine ; pharmacology ; Animals ; Dogs ; Epicardial Mapping ; Heart Atria ; cytology ; drug effects ; physiopathology ; Mechanotransduction, Cellular

This paper mainly discusses the interdisciplinary research of the life science and information technology, and also describes some research topics and direction, such as bioinformatics, biomedical optics, micro & nanotechnologies, bionics, etc.
Biomedical Engineering ; trends ; Biomedical Research ; Biomedical Technology ; Interdisciplinary Communication ; Mechanotransduction, Cellular ; Medical Informatics ; Molecular Biology

The purpose of this study was to investigate the effect on the expression of NF-kappaBp65 of osteoblast-like cell under stretch load with the same amplitude but different daily loading times. The osteoblast-like cells MG-63 were passage cultured and stretched by the four-point-bend loading device; based on the daily loading times, the osteoblast-like cells were randomly divided into four groups. The first was the control, the others were stretched with mechanical tension with the same amplitude of 2,000 mu strain and at the same frequency of 0.5 Hz., but the daily loading times were 1 time/d, 2 times/d, 4 times/d differently for each group, the periods of mechanical tension applied to the cells of the three groups were all 60 min/d and lasted for 2d total. After the cells being streteched, the expression levels of NF-kappaBp65 of the osteoblast-like cells of the three groups and control group were investigated by using the techniques of immunohistochemistry, and were compared with each other. The results showed that the positive expression ratios of the four groups were different significantly; the positive expression ratio of the control was lower than those of the other three groups; the positive expression ratio of the 4 times/d group was higher than those of the other two stretched groups; the positive expression ratio of the 2 times/d group was higher than that of the 1 time/d group. The results suggested that when the osteoblast-like cell was under the stretch load with different daily loading times but the same amplitude, the expression ratio of NF-kappaBp65 in the cell increased with the rising of the stimulating times. It means that the mechanical strain with high daily loading times could promote the transcriptional level of osteoblast-like cell more effectively.
Cell Line ; Humans ; Mechanotransduction, Cellular ; Osteoblasts ; cytology ; metabolism ; Stress, Mechanical ; Time Factors ; Transcription Factor RelA ; biosynthesis

OBJECTIVETo study the role of microfilament polymerization in menchanotransduction by human periodontal ligament fibroblast (hPDLFs).

METHODSIn tension-force group, hPDLFs were treated by tension-force values of 18% for 8 h, 16 h, 24 h. In tension-force and inhibitor group, the sample was treated with 5 microg/mL cytochalasin B before using tension-forece. Each sample was collected and the expression of cyclooxygenase-2 was measured by using immunohistoche staining.

RESULTSIn tension-force group, the expression of cyclooxygenase-2 enhanced with the extension of loading time. In tension-force and inhibitor group, cyclooxygenase-2 expression was depressed and had no relation with loading time.

CONCLUSIONTension-force induced cyclooxygenase-2 expression is mediated by microfilament, disruption of the microfilament polymerization will destroy mechanotransduction in hPDLFs.

Cells sense various in vivo mechanical stimuli, which initiate downstream signaling to mechanical forces. While a body of evidences is presented on the impact of limited mechanical regulators in past decades, the mechanisms how biomechanical responses globally affect cell function need to be addressed. Complexity and diversity of in vivo mechanical clues present distinct patterns of shear flow, tensile stretch, or mechanical compression with various parametric combination of its magnitude, duration, or frequency. Thus, it is required to understand, from the viewpoint of mechanobiology, what mechanical features of cells are, why mechanical properties are different among distinct cell types, and how forces are transduced to downstream biochemical signals. Meanwhile, those in vitro isolated mechanical stimuli are usually coupled together in vivo, suggesting that the different factors that are in effect individually could be canceled out or orchestrated with each other. Evidently, omics analysis, a powerful tool in the field of system biology, is advantageous to combine with mechanobiology and then to map the full-set of mechanically sensitive proteins and transcripts encoded by its genome. This new emerging field, namely mechanomics, makes it possible to elucidate the global responses under systematically-varied mechanical stimuli. This review discusses the current advances in the related fields of mechanomics and elaborates how cells sense external forces and activate the biological responses.
Biomechanical Phenomena ; Gene Expression Regulation ; Humans ; Mechanotransduction, Cellular ; Models, Biological ; Proteome ; genetics ; metabolism ; Stress, Physiological ; Transcriptome

The reconstruction of tactile function during the repair of skin damage caused by factors including burns is inseparable from the functional regeneration of tactile receptor Merkel cells. Merkel cells mainly exist in the basal layer of the epidermis and are closely connected with nerves to form Merkel cell-nerve complexes, which play an important role in biological organisms. A large number of studies have shown that Merkel cells conduct precise transmission of mechanical force stimuli through the mechanically gated ion channels PIEZO2, and perform the function of tactile receptors. In this paper, we discussed the characteristics of Merkel cells and analyzed the different subgroups that may possibly exist in this type of cells and their functions, at the same time, we investigated the animal model research of touch-related diseases and the clinical diseases related to touch, revealing the importance of Merkel cell function research.
Animals ; Ion Channels/metabolism* ; Mechanotransduction, Cellular/physiology* ; Merkel Cells/physiology* ; Skin/metabolism* ; Touch/physiology*

Mechanical stimulus is critical to cardiovascular development during embryogenesis period.The mechanoreceptors of endocardial cells and cardiac myocytes may sense mechanical signals and initiate signal transduction that induce gene expression at a cellular level,and then translate molecular-level events into tissue-level deformations,thus guiding embryo development.This review summarizes the regulatory roles of mechanical signals in the early cardiac development including the formation of heart tube,looping,valve and septal morphogenesis,ventricular development and maturation.Further,we discuss the potential mechanical transduction mechanisms of platelet endothelial cell adhesion molecule 1-vascular endothelial-cadherin-vascular endothelial growth factor receptor 2 complex,primary cilia,ion channels,and other mechanical sensors that affect some cardiac malformations.
Animals ; Heart/embryology* ; Humans ; Mechanotransduction, Cellular ; Myocytes, Cardiac/physiology* ; Vascular Endothelial Growth Factor A/metabolism*

Microenvironmental biophysical factors play a fundamental role in controlling cell behaviors including cell morphology, proliferation, adhesion and differentiation, and even determining the cell fate. Cells are able to actively sense the surrounding mechanical microenvironment and change their cellular morphology to adapt to it. Although cell morphological changes have been considered to be the first and most important step in the interaction between cells and their mechanical microenvironment, their regulatory network is not completely clear. In the current study, we generated silicon-based elastomer polydimethylsiloxane (PDMS) substrates with stiff (15:1, PDMS elastomer vs. curing agent) and soft (45:1) stiffnesses, which showed the Young's moduli of ~450 kPa and 46 kPa, respectively, and elucidated a new path in cytoskeleton re-organization in chondrocytes in response to changed substrate stiffnesses by characterizing the axis shift from the secreted extracellular protein laminin β1, focal adhesion complex protein FAK to microfilament bundling. We first showed the cellular cytoskeleton changes in chondrocytes by characterizing the cell spreading area and cellular synapses. We then found the changes of secreted extracellular linkage protein, laminin β1, and focal adhesion complex protein, FAK, in chondrocytes in response to different substrate stiffnesses. These two proteins were shown to be directly interacted by Co-IP and colocalization. We next showed that impact of FAK on the cytoskeleton organization by showing the changes of microfilament bundles and found the potential intermediate regulators. Taking together, this modulation axis of laminin β1-FAK-microfilament could enlarge our understanding about the interdependence among mechanosensing, mechanotransduction, and cytoskeleton re-organization.
Cell Adhesion ; Chondrocytes ; Cytoskeleton/metabolism* ; Elastomers/metabolism* ; Laminin/metabolism* ; Mechanotransduction, Cellular