The role of mechanically sensitive ion channel Piezo1 in bone remodeling

Roles of Piezo1 in chronic inflammatory diseases and prospects for drug treatment (Review)

The human body is chronically stimulated by various mechanical forces and the body cells can sense harmful stimuli through mechanotransduction to induce chronic inflammation. Piezo type mechanosensitive ion channel component 1 (Piezo1), a novel transmembrane mechanosensitive cation channel, is widely expressed in inflammatory cells, such as neutrophils, macrophages and endothelial cells, as well as in non‑inflammatory cells, such as osteoblasts, osteoclasts and periodontal cells. A growing number of studies have demonstrated that Piezo1 senses changes in environmental mechanical forces, regulates cellular functions and influences the development and regression of chronic inflammation. The present study summarized the roles of Piezo1 and its possible mechanisms in some common chronic inflammatory diseases and evaluated the potential application of drugs that modulate its activity, so as to prove that Piezo1 is likely to become a new target for the treatment of inflammatory diseases.15.

The Mechanosensitive PIEZO1 Channel Contributes to the Reaction of RAW264.7 Macrophages to Mechanical Strain

The mechanosensitive channel 'piezo type mechanosensitive ion channel component 1' (PIEZO1) plays a regulatory role in the response of periodontal ligament fibroblasts (PDLFs) to the mechanical strain that occurs during orthodontic tooth movement. In addition to PDLFs, immune cells such as macrophages are also exposed to mechanical stimuli. Macrophages respond to mechanical strain with increased expression of inflammatory mediators. The role of PIEZO1 in this response remains elusive. To investigate the effect of PIEZO1 activation, RAW264.7 macrophages were stimulated with the PIEZO1 activator YODA1 without concurrent application of pressure. To further examine the specific role of PIEZO1 during mechanical strain, RAW264.7 macrophages were exposed to mechanical strain without and with simultaneous inhibition of PIEZO1 either by chemical inhibition (GsMTx4) or siRNA silencing. The expression of genes and proteins involved in orthodontic tooth movement was examined by quantitative PCR, western blot, and enzyme-linked immunosorbent assay (ELISA). Activation of PIEZO1 by YODA1 or mechanical strain increased the expression of inflammatory cytokines and osteoprotegerin (Opg), which is critically involved in bone remodeling processes. Conversely, inhibition of the PIEZO1 channel attenuates the effects of mechanical stress. In conclusion, our data demonstrate that the PIEZO1 channel is a major contributor to the response of macrophages to mechanical strain encountered during orthodontic tooth movement and affects the expression of inflammatory and bone remodeling factors.

Enhancing Bone Health with Conjugated Linoleic Acid: Mechanisms, Challenges, and Innovative Strategies

Conjugated linoleic acid (CLA) is a bioactive compound known for its anti-inflammatory, anti-carcinogenic, and metabolic effects, with growing interest in its role in supporting bone health. Preclinical studies, particularly those involving the t10c12 isomer, have shown that CLA can enhance bone mineral density (BMD) by enhancing bone formation and reducing bone resorption, indicating its potential as a therapeutic agent to improve bone health. However, clinical trials have yielded inconsistent results, underscoring the difficulty in translating animal model successes to human applications. A major challenge is CLA's low water solubility, poor absorption, and limited bioavailability, which restrict its therapeutic effectiveness. To address these issues, nanoparticle-based delivery systems have been proposed to improve its solubility, stability, and resistance to oxidative damage, thereby enhancing its bioactivity. Recent studies also suggest that electrical stimulation can stimulate bone regeneration by promoting bone cell proliferation, differentiation, and adherence to scaffolds. This review explores the combined use of CLA supplementation and electrical stimulation as a novel approach to improving bone health, particularly in osteoporosis management. By integrating CLA's biological effects with the regenerative potential of electrical stimulation, this multimodal strategy offers a promising method for enhancing bone restoration, with significant implications for clinical applications in bone health.

Molecular mechanism of mechanical pressure induced changes in the microenvironment of intervertebral disc degeneration

BACKGROUND

Lower back pain, as a typical clinical symptom of spinal degenerative diseases, is emerging as a major social problem. According to recent researches, the primary cause of this problem is intervertebral disc degeneration (IVDD). IVDD is closely associated with factors such as age, genetics, mechanical stimulation (MS), and inadequate nutrition. In recent years, an increasing number of studies have further elucidated the relationship between MS and IVDD. However, the exact molecular mechanisms by which MS induces IVDD remain unclear, highlighting the need for in-depth exploration and study of the relationship between MS and IVDD.

METHODS

Search for relevant literature on IVDD and MS published from January 1, 2010, to the present in the PubMed database.

RESULTS

One of the main causes of IVDD is MS, and loading modalities have an impact on the creation of matrix metalloproteinase, the metabolism of the cellular matrix, and other biochemical processes in the intervertebral disc. Nucleus pulposus cell death induced by MS, cartilage end-plate destruction accompanied by pyroptosis, apoptosis, iron death, senescence, autophagy, oxidative stress, inflammatory response, and ECM degradation interact with one another to form a cooperative signaling network.

CONCLUSION

This review discusses the molecular mechanisms of the changes in the microenvironment of intervertebral discs caused by mechanical pressure, explores the interaction between mechanical pressure and IVDD, and provides new insights and approaches for the clinical prevention and treatment of IVDD.

Piezoelectric biomaterials with embedded ionic liquids for improved orthopedic interfaces through osseointegration and antibacterial dual characteristics

Orthopedic implant failures, primarily attributed to aseptic loosening and implant site infections, pose significant challenges to patient recovery and lead to revision surgeries. Combining piezoelectric materials with ionic liquids as interfaces for orthopedic implants presents an innovative approach to addressing both issues simultaneously. In this study, films of poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) incorporated with 1-ethyl-3-methylimidazolium hydrogen sulfate ([Emim][HSO4]) ionic liquid were developed. These films exhibited strong antibacterial properties, effectively reducing biofilm formation, thereby addressing implant-related infections. Furthermore, stem cell-based differentiation assays exposed the potential of the composite materials to induce osteogenesis. Interestingly, our findings also revealed the upregulation of calcium channel expression as a result of electromechanical stimulation, pointing to a mechanistic basis for the observed biological effects. This work highlights the potential of piezoelectric materials with ionic liquids to improve the longevity and biocompatibility of orthopedic implants. Offering dual-functionality for infection prevention and bone integration, these advancements hold significant potential for advancing orthopedic implant technologies and improving patient outcomes.

Piezo ion channels: long-sought-after mechanosensors mediating hypertension and hypertensive nephropathy

Recent advances in mechanobiology and the discovery of mechanosensitive ion channels have opened a new era of research on hypertension and related diseases. Piezo1 and Piezo2, first reported in 2010, are regarded as bona fide mechanochannels that mediate various biological and pathophysiological phenomena in multiple tissues and organs. For example, Piezo channels have pivotal roles in blood pressure control, triggering shear stress-induced nitric oxide synthesis and vasodilation, regulating baroreflex in the carotid sinus and aorta, and releasing renin from renal juxtaglomerular cells. Herein, we provide an overview of recent literature on the roles of Piezo channels in the pathogenesis of hypertension and related kidney damage, including our experimental data on the involvement of Piezo1 in podocyte injury and that of Piezo2 in renin expression and renal fibrosis in animal models of hypertensive nephropathy. The mechanosensitive ion channels Piezo1 and Piezo2 play various roles in the pathogenesis of systemic hypertension by acting on vascular endothelial cells, baroreceptors in the carotid artery and aorta, and the juxtaglomerular apparatus. Piezo channels also contribute to hypertensive nephropathy by acting on mesangial cells, podocytes, and perivascular mesenchymal cells.