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1.
Heliyon ; 10(12): e32949, 2024 Jun 30.
Article in English | MEDLINE | ID: mdl-39021958

ABSTRACT

Osteoclasts are essential for bone remodeling by adapting their resorptive activity in response to their mechanical in vivo environment. However, the molecular mechanisms underlying this process remain unclear. Here, we demonstrated the role of tartrate-resistant acid phosphatase (TRAP, Acp5), a key enzyme secreted by osteoclasts, in bone remodeling and mechanosensitivity. Using CRISPR/Cas9 reporter mice, we demonstrated bone cell reporter (BCRIbsp/Acp5) mice feature fluorescent TRAP-deficient osteoclasts and examined their activity during mechanically driven trabecular bone remodeling. Although BCRIbsp/Acp5 mice exhibited trabecular bone impairments and reduced resorption capacity in vitro, RNA sequencing revealed unchanged levels of key osteoclast-associated genes such as Ctsk, Mmp9, and Calcr. These findings, in conjunction with serum carboxy-terminal collagen crosslinks (CTX) and in vivo mechanical loading outcomes collectively indicated an unaltered bone resorption capacity of osteoclasts in vivo. Furthermore, we demonstrated similar mechanoregulation during trabecular bone remodeling in BCRIbsp/Acp5 and wild-type (WT) mice. Hence, this study provides valuable insights into the dynamics of TRAP activity in the context of bone remodeling and mechanosensation.

2.
J Nanobiotechnology ; 22(1): 327, 2024 Jun 10.
Article in English | MEDLINE | ID: mdl-38858689

ABSTRACT

Magnetogenetics emerges as a transformative approach for modulating cellular signaling pathways through the strategic application of magnetic fields and nanoparticles. This technique leverages the unique properties of magnetic nanoparticles (MNPs) to induce mechanical or thermal stimuli within cells, facilitating the activation of mechano- and thermosensitive proteins without the need for traditional ligand-receptor interactions. Unlike traditional modalities that often require invasive interventions and lack precision in targeting specific cellular functions, magnetogenetics offers a non-invasive alternative with the capacity for deep tissue penetration and the potential for targeting a broad spectrum of cellular processes. This review underscores magnetogenetics' broad applicability, from steering stem cell differentiation to manipulating neuronal activity and immune responses, highlighting its potential in regenerative medicine, neuroscience, and cancer therapy. Furthermore, the review explores the challenges and future directions of magnetogenetics, including the development of genetically programmed magnetic nanoparticles and the integration of magnetic field-sensitive cells for in vivo applications. Magnetogenetics stands at the forefront of cellular manipulation technologies, offering novel insights into cellular signaling and opening new avenues for therapeutic interventions.


Subject(s)
Magnetic Fields , Magnetite Nanoparticles , Signal Transduction , Humans , Animals , Magnetite Nanoparticles/chemistry , Cell Differentiation , Regenerative Medicine/methods , Neurons/metabolism , Stem Cells/metabolism , Neoplasms
3.
Am J Physiol Lung Cell Mol Physiol ; 327(2): L150-L159, 2024 Aug 01.
Article in English | MEDLINE | ID: mdl-38771147

ABSTRACT

Alteration in the normal mechanical forces of breathing can contribute to changes in contractility and remodeling characteristic of airway diseases, but the mechanisms that mediate these effects in airway cells are still under investigation. Airway smooth muscle (ASM) cells contribute to both contractility and extracellular matrix (ECM) remodeling. In this study, we explored ASM mechanisms activated by mechanical stretch, focusing on mechanosensitive piezo channels and the key Ca2+ regulatory protein stromal interaction molecule 1 (STIM1). Expression of Ca2+ regulatory proteins, including STIM1, Orai1, and caveolin-1, mechanosensitive ion channels Piezo-1 and Piezo-2, and NLRP3 inflammasomes were upregulated by 10% static stretch superimposed on 5% cyclic stretch. These effects were blunted by STIM1 siRNA. Histamine-induced [Ca2+]i responses and inflammasome activation were similarly blunted by STIM1 knockdown. These data show that the effects of mechanical stretch in human ASM cells are mediated through STIM1, which activates multiple pathways, including Piezo channels and the inflammasome, leading to potential downstream changes in contractility and ECM remodeling.NEW & NOTEWORTHY Mechanical forces on the airway can contribute to altered contractility and remodeling in airway diseases, but the mechanisms are not clearly understood. Using human airway smooth muscle cells exposed to cyclic forces with static stretch to mimic breathing and static pressure, we found that the effects of stretch are mediated through STIM1, resulting in the activation of multiple pathways, including Piezo channels and the inflammasome, with potential downstream influences on contractility and remodeling.


Subject(s)
Myocytes, Smooth Muscle , Stromal Interaction Molecule 1 , Humans , Stromal Interaction Molecule 1/metabolism , Stromal Interaction Molecule 1/genetics , Myocytes, Smooth Muscle/metabolism , Neoplasm Proteins/metabolism , Neoplasm Proteins/genetics , Inflammasomes/metabolism , Stress, Mechanical , Mechanotransduction, Cellular , Muscle, Smooth/metabolism , Ion Channels/metabolism , Caveolin 1/metabolism , Caveolin 1/genetics , Signal Transduction , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , NLR Family, Pyrin Domain-Containing 3 Protein/genetics , Calcium/metabolism , Cells, Cultured , Muscle Contraction/physiology , Airway Remodeling/physiology , ORAI1 Protein/metabolism , ORAI1 Protein/genetics
4.
EMBO J ; 43(13): 2715-2732, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38769437

ABSTRACT

Microtubules regulate cell polarity and migration via local activation of focal adhesion turnover, but the mechanism of this process is insufficiently understood. Molecular complexes containing KANK family proteins connect microtubules with talin, the major component of focal adhesions. Here, local optogenetic activation of KANK1-mediated microtubule/talin linkage promoted microtubule targeting to an individual focal adhesion and subsequent withdrawal, resulting in focal adhesion centripetal sliding and rapid disassembly. This sliding is preceded by a local increase of traction force due to accumulation of myosin-II and actin in the proximity of the focal adhesion. Knockdown of the Rho activator GEF-H1 prevented development of traction force and abolished sliding and disassembly of focal adhesions upon KANK1 activation. Other players participating in microtubule-driven, KANK-dependent focal adhesion disassembly include kinases ROCK, PAK, and FAK, as well as microtubules/focal adhesion-associated proteins kinesin-1, APC, and αTAT. Based on these data, we develop a mathematical model for a microtubule-driven focal adhesion disruption involving local GEF-H1/RhoA/ROCK-dependent activation of contractility, which is consistent with experimental data.


Subject(s)
Focal Adhesions , Kinesins , Microtubules , Rho Guanine Nucleotide Exchange Factors , Focal Adhesions/metabolism , Microtubules/metabolism , Humans , Rho Guanine Nucleotide Exchange Factors/metabolism , Rho Guanine Nucleotide Exchange Factors/genetics , Kinesins/metabolism , Kinesins/genetics , Adaptor Proteins, Signal Transducing/metabolism , Adaptor Proteins, Signal Transducing/genetics , Cytoskeletal Proteins/metabolism , Cytoskeletal Proteins/genetics , Myosin Type II/metabolism , Talin/metabolism , Talin/genetics , Animals
5.
Biochem Soc Trans ; 52(2): 911-922, 2024 Apr 24.
Article in English | MEDLINE | ID: mdl-38629718

ABSTRACT

To date, there is no general physical model of the mechanism by which unfolded polypeptide chains with different properties are imported into the mitochondria. At the molecular level, it is still unclear how transit polypeptides approach, are captured by the protein translocation machinery in the outer mitochondrial membrane, and how they subsequently cross the entropic barrier of a protein translocation pore to enter the intermembrane space. This deficiency has been due to the lack of detailed structural and dynamic information about the membrane pores. In this review, we focus on the recently determined sub-nanometer cryo-EM structures and our current knowledge of the dynamics of the mitochondrial two-pore outer membrane protein translocation machinery (TOM core complex), which provide a starting point for addressing the above questions. Of particular interest are recent discoveries showing that the TOM core complex can act as a mechanosensor, where the pores close as a result of interaction with membrane-proximal structures. We highlight unusual and new correlations between the structural elements of the TOM complexes and their dynamic behavior in the membrane environment.


Subject(s)
Mitochondria , Mitochondrial Membranes , Mitochondria/metabolism , Mitochondrial Membranes/metabolism , Mitochondrial Precursor Protein Import Complex Proteins , Protein Transport , Cryoelectron Microscopy/methods , Humans , Mitochondrial Membrane Transport Proteins/metabolism , Mitochondrial Membrane Transport Proteins/chemistry , Models, Molecular , Protein Conformation , Animals
6.
Int J Mol Sci ; 25(7)2024 Mar 27.
Article in English | MEDLINE | ID: mdl-38612536

ABSTRACT

The endometrial epithelium and underlying stroma undergo profound changes to support and limit embryo adhesion and invasion, which occur in the secretory phase of the menstrual cycle during the window of implantation. This coincides with a peak in progesterone and estradiol production. We hypothesized that the interplay between hormone-induced changes in the mechanical properties of the endometrial epithelium and stroma supports this process. To study it, we used hormone-responsive endometrial adenocarcinoma-derived Ishikawa cells growing on substrates of different stiffness. We showed that Ishikawa monolayers on soft substrates are more tightly clustered and uniform than on stiff substrates. Probing for mechanical alterations, we found accelerated stress-relaxation after apical nanoindentation in hormone-stimulated monolayers on stiff substrates. Traction force microscopy furthermore revealed an increased number of foci with high traction in the presence of estradiol and progesterone on soft substrates. The detection of single cells and small cell clusters positive for the intermediate filament protein vimentin and the progesterone receptor further underscored monolayer heterogeneity. Finally, adhesion assays with trophoblast-derived AC-1M-88 spheroids were used to examine the effects of substrate stiffness and steroid hormones on endometrial receptivity. We conclude that the extracellular matrix and hormones act together to determine mechanical properties and, ultimately, embryo implantation.


Subject(s)
Extracellular Matrix , Progesterone , Female , Humans , Epithelium , Menstrual Cycle , Estradiol
7.
Curr Opin Behav Sci ; 562024 Apr.
Article in English | MEDLINE | ID: mdl-38505510

ABSTRACT

Ultrasound neuromodulation is a promising technology that could revolutionize study and treatment of brain conditions ranging from mood disorders to Alzheimer's disease and stroke. An understanding of how ultrasound directly modulates specific ion channels could provide a roadmap for targeting specific neurological circuits and achieving desired neurophysiological outcomes. Although experimental challenges make it difficult to unambiguously identify which ion channels are sensitive to ultrasound in vivo, recent progress indicates that there are likely several different ion channels involved, including members of the K2P, Piezo, and TRP channel families. A recent result linking TRPM2 channels in the hypothalamus to induction of torpor by ultrasound in rodents demonstrates the feasibility of targeting a specific ion channel in a specific population of neurons.

8.
J Orthop Res ; 42(6): 1267-1275, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38234146

ABSTRACT

Continuous administration of low-intensity whole-body vibration (WBV) gradually diminishes bone mechanosensitivity over time, leading to a weakening of its osteogenic effect. We investigated whether discretizing WBV into bouts with short rest intervals was effective in enhancing osteoporotic bone repair. Ten-week-old female mice were ovariectomized and underwent drill-hole defect surgery (Day 0) on the right tibial diaphysis at 11 weeks of age. The mice underwent one of three regimens starting from Day 1 for 5 days/week: continuous WBV at 45 Hz and 0.3 g for 7.5 min/day (cWBV); 3-s bouts of WBV at 45 Hz, 0.3 g followed by 9-s rest intervals, repeated for 30 min/day (repeated bouts of whole-body vibration with short rest intervals [rWBV]); or a sham treatment. Both the cWBV and rWBV groups received a total of 20,250 vibration cycles per day. On either Day 7 or 14 posteuthanasia (n = 6/group/timepoint), the bone and angiogenic vasculature in the defect were computed tomography imaged using synchrotron light. By Day 14, the bone repair was most advanced in the rWBV group, showing a higher bone volume fraction and a more uniform mineral distribution compared with the sham group. The cWBV group exhibited an intermediate level of bone repair between the sham and rWBV groups. The rWBV group had a decrease in large-sized angiogenic vessels, while the cWBV group showed an increase in such vessels. In conclusion, osteoporotic bone repair was enhanced by WBV bouts with short rest intervals, which may potentially be attributed to the improved mechanosensitivity of osteogenic cells and alterations in angiogenic vasculature.


Subject(s)
Mice, Inbred C57BL , Osteoporosis , Vibration , Animals , Vibration/therapeutic use , Female , Osteoporosis/therapy , Mice
9.
Toxins (Basel) ; 16(1)2024 01 07.
Article in English | MEDLINE | ID: mdl-38251246

ABSTRACT

Botulinum neurotoxin A (BoNT/A) is a potent neurotoxin that silences cholinergic neurotransmission through the cleavage of the synaptic protein SNAP-25. Previous studies have shown that, in addition to its paralytic effects, BoNT/A can inhibit sensory nerve activity. The aim of this study was to identify how BoNT/A inhibits afferent signalling from the bladder. To investigate the role of SNAP-25 cleavage in the previously reported BoNT/A-dependent inhibition of sensory signalling, we developed a recombinant form of BoNT/A with an inactive light chain, rBoNT/A (0), unable to paralyse muscle. We also developed recombinant light chain (LC)-domain-only proteins to better understand the entry mechanisms, as the heavy chain (HC) of the protein is responsible for the internalisation of the light chain. We found that, despite a lack of catalytic activity, rBoNT/A (0) potently inhibited the afferent responses to bladder distension to a greater degree than catalytically active rBoNT/A. This was also clear from the testing of the LC-only proteins, as the inactive rLC/A (0) protein inhibited afferent responses significantly more than the active rLC/A protein. Immunohistochemistry for cleaved SNAP-25 was negative, and purinergic and nitrergic antagonists partially and totally reversed the sensory inhibition, respectively. These data suggest that the BoNT/A inhibition of sensory nerve activity in this assay is not due to the classical well-characterised 'double-receptor' mechanism of BoNT/A, is independent of SNAP25 cleavage and involves nitrergic and purinergic signalling mechanisms.


Subject(s)
Botulinum Toxins, Type A , Signal Transduction , Neurotoxins , Biological Assay , Muscles
10.
Exp Physiol ; 109(1): 135-147, 2024 01.
Article in English | MEDLINE | ID: mdl-36951012

ABSTRACT

By translating mechanical forces into molecular signals, proprioceptive neurons provide the CNS with information on muscle length and tension, which is necessary to control posture and movement. However, the identities of the molecular players that mediate proprioceptive sensing are largely unknown. Here, we confirm the expression of the mechanosensitive ion channel ASIC2 in proprioceptive sensory neurons. By combining in vivo proprioception-related functional tests with ex vivo electrophysiological analyses of muscle spindles, we showed that mice lacking Asic2 display impairments in muscle spindle responses to stretch and motor coordination tasks. Finally, analysis of skeletons of Asic2 loss-of-function mice revealed a specific effect on spinal alignment. Overall, we identify ASIC2 as a key component in proprioceptive sensing and a regulator of spine alignment.


Subject(s)
Acid Sensing Ion Channels , Proprioception , Animals , Mice , Acid Sensing Ion Channels/metabolism , Muscle Spindles/physiology , Proprioception/physiology , Sensory Receptor Cells/metabolism
11.
Macromol Biosci ; 24(1): e2300110, 2024 Jan.
Article in English | MEDLINE | ID: mdl-37747449

ABSTRACT

There is a tremendous interest in developing hydrogels as tunable in vitro cell culture platforms to study cell response to mechanical cues in a controlled manner. However, little is known about how common cell culture techniques, such as serial expansion on tissue culture plastic, affect subsequent cell behavior when cultured on hydrogels. In this work, a methacrylated hyaluronic acid hydrogel platform is leveraged to study stromal cell mechanotransduction. Hydrogels are first formed through thiol-Michael addition to model normal soft tissue (e.g., lung) stiffness (E ≈ 1 kPa). Secondary cross-linking via radical photopolymerization of unconsumed methacrylates allows matching of early- (E ≈ 6 kPa) and late-stage fibrotic tissue (E ≈ 50 kPa). Early passage (P1) human bone marrow mesenchymal stromal cells (hMSCs) display increased spreading, myocardin-related transcription factor-A (MRTF-A) nuclear localization, and focal adhesion size with increasing hydrogel stiffness. However, late passage (P5) hMSCs show reduced sensitivity to substrate mechanics with lower MRTF-A nuclear translocation and smaller focal adhesions on stiffer hydrogels compared to early passage hMSCs. Similar trends are observed in an immortalized human lung fibroblast line. Overall, this work highlights the implications of standard cell culture practices on investigating cell response to mechanical signals using in vitro hydrogel models.


Subject(s)
Hyaluronic Acid , Hydrogels , Humans , Hydrogels/pharmacology , Hyaluronic Acid/pharmacology , Mechanotransduction, Cellular , Stromal Cells , Cell Culture Techniques/methods
12.
J Biol Chem ; 300(1): 105524, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38043795

ABSTRACT

The renal collecting duct is continuously exposed to a wide spectrum of fluid flow rates and osmotic gradients. Expression of a mechanoactivated Piezo1 channel is the most prominent in the collecting duct. However, the status and regulation of Piezo1 in functionally distinct principal and intercalated cells (PCs and ICs) of the collecting duct remain to be determined. We used pharmacological Piezo1 activation to quantify Piezo1-mediated [Ca2+]i influx and single-channel activity separately in PCs and ICs of freshly isolated collecting ducts with fluorescence imaging and electrophysiological tools. We also employed a variety of systemic treatments to examine their consequences on Piezo1 function in PCs and ICs. Piezo1 selective agonists, Yoda-1 or Jedi-2, induced a significantly greater Ca2+ influx in PCs than in ICs. Using patch clamp analysis, we recorded a Yoda-1-activated nonselective channel with 18.6 ± 0.7 pS conductance on both apical and basolateral membranes. Piezo1 activity in PCs but not ICs was stimulated by short-term diuresis (injections of furosemide) and reduced by antidiuresis (water restriction for 24 h). However, prolonged stimulation of flow by high K+ diet decreased Yoda-1-dependent Ca2+ influx without changes in Piezo1 levels. Water supplementation with NH4Cl to induce metabolic acidosis stimulated Piezo1 activity in ICs but not in PCs. Overall, our results demonstrate functional Piezo1 expression in collecting duct PCs (more) and ICs (less) on both apical and basolateral sides. We also show that acute changes in fluid flow regulate Piezo1-mediated [Ca2+]i influx in PCs, whereas channel activity in ICs responds to systemic acid-base stimuli.


Subject(s)
Calcium , Ion Channels , Kidney Tubules, Collecting , Cell Membrane , Kidney Tubules, Collecting/cytology , Kidney Tubules, Collecting/metabolism , Pyrazines/pharmacology , Thiadiazoles/pharmacology , Water/metabolism , Ion Channels/agonists , Ion Channels/metabolism , Animals , Mice , Calcium/metabolism
13.
Biochim Biophys Acta Biomembr ; 1866(2): 184262, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38081494

ABSTRACT

The endoplasmic reticulum acts as a protein quality control center where a range of chaperones and foldases facilitates protein folding. IRE1 is a sensory transmembrane protein that transduces signals of proteotoxic stress by forming clusters and activating a cellular program called the unfolded protein response (UPR). Recently, membrane thickness variation due to membrane compositional changes have been shown to drive IRE1 cluster formation, activating the UPR even in the absence of proteotoxic stress. Here, we demonstrate a direct relationship between bilayer tension and UPR activation based on IRE1 dimer stability. The stability of the IRE1 dimer in a (50%DOPC-50%POPC) membrane at different applied bilayer tensions was analyzed via molecular dynamics simulations. The potential of mean force for IRE1 dimerization predicts a higher concentration of IRE1 dimers for both tensed and compressed ER membranes. This study shows that IRE1 may be a mechanosensitive membrane protein and establishes a direct biophysical relationship between bilayer tension and UPR activation.


Subject(s)
Protein Serine-Threonine Kinases , Signal Transduction , Protein Serine-Threonine Kinases/genetics , Protein Serine-Threonine Kinases/metabolism , Unfolded Protein Response , Endoplasmic Reticulum/metabolism , Membrane Proteins/metabolism , Cluster Analysis
14.
Healthcare (Basel) ; 11(24)2023 Dec 11.
Article in English | MEDLINE | ID: mdl-38132028

ABSTRACT

The straight leg raise test (SLR) has been proposed to detect increased nerve mechanosensitivity of the lower limbs in individuals with low back pain. However, its validity in the diagnosis of lumbosacral radiculopathy shows very variable results. The aim of this study was to analyse the diagnostic validity of the SLR including well-defined diagnostic criteria (a change in symptoms with the structural differentiation manoeuvre and the reproduction of the patient's symptoms during the test or the asymmetries in the range of motion or symptoms location between limbs) in a sample of participants in phase III with suspicion of lumbar radiculopathy using the electrodiagnostic studies (EDX) as the reference standard. A phase III diagnostic accuracy study was designed. In total, 142 individuals with suspected lumbosacral radiculopathy referred for EDX participated in the study. Each participant was tested with EDX and SLR. SLR was considered positive using three diagnostic criteria. The sensitivity of the SLR for Criterion 3 was 89.02% (CI 81.65-96.40), the specificity was 25.00% (CI 13.21-36.79), and the positive and negative likelihood ratios were 1.19 (CI 1.01-1.40) and 0.44 (0.21-0.94), respectively. SLR showed limited validity in the diagnosis of lumbosacral radiculopathy. The incorporation of more objective diagnostic criteria (asymmetry in range of motion or localisation of symptoms) improved the diagnostic validity but the imprecision of the confidence intervals limited the interpretation of the results.

15.
Nano Lett ; 23(23): 10719-10724, 2023 Dec 13.
Article in English | MEDLINE | ID: mdl-37988562

ABSTRACT

Organic materials are promising candidates for thermoelectric cooling and energy harvesting at room temperature. However, their electrical conductance (G) and Seebeck coefficient (S) need to be improved to make them technologically competitive. Therefore, radically new strategies need to be developed to tune their thermoelectric properties. Here, we demonstrate that G and S can be tuned mechanically in paramagnetic metallocenes, and their thermoelectric properties can be significantly enhanced by the application of mechanical forces. With a 2% junction compression, the full thermoelectric figure of merit is enhanced by more than 200 times. We demonstrate that this is because spin transport resonances in paramagnetic metallocenes are strongly sensitive to the interaction between organic ligands and the metal center, which is not the case in their diamagnetic analogue. These results open a new avenue for the development of organic thermoelectric materials for cooling future quantum computers and generating electricity from low-grade energy sources.

16.
Angew Chem Int Ed Engl ; 62(35): e202305896, 2023 08 28.
Article in English | MEDLINE | ID: mdl-37438325

ABSTRACT

Membrane curvature reflects physical forces operating on the lipid membrane, which plays important roles in cellular processes. Here, we design a mechanosensitive DNA (MSD) nanomachine that mimics natural mechanosensitive PIEZO channels to convert the membrane tension changes of lipid vesicles with different sizes into fluorescence signals in real time. The MSD nanomachine consists of an archetypical six-helix-bundle DNA nanopore, cholesterol-based membrane anchors, and a solvatochromic fluorophore, spiropyran (SP). We find that the DNA nanopore effectively amplifies subtle variations of the membrane tension, which effectively induces the isomerization of weakly emissive SP into highly emissive merocyanine isomers for visualizing membrane tension changes. By measuring the membrane tension via the fluorescence of MSD nanomachine, we establish the correlation between the membrane tension and the curvature that follows the Young-Laplace equation. This DNA nanotechnology-enabled strategy opens new routes to studying membrane mechanics in physiological and pathological settings.


Subject(s)
Nanopores , Nanotechnology , Fluorescence , DNA , Lipids , Cell Membrane
17.
Medicina (Kaunas) ; 59(7)2023 Jul 08.
Article in English | MEDLINE | ID: mdl-37512082

ABSTRACT

Background and Objectives: Practitioners of martial arts such as Taekwondo are likelier to experience back pain during training or competition. As the back pain of taekwondo athletes shows various symptoms depending on the athlete's characteristics, such as technique and movement, a case study was conducted to verify the intervention effect suitable for individual traits. We examined the effects of a complex pain control program on pain, mechanosensitivity, and physical function in a Taekwondo athlete with recurrent low back pain (LBP). Materials and Methods: A Taekwondo athlete with LBP was recruited from D University, Busan. The intervention program was performed for 45 min twice a week for 3 weeks, and the patient was followed up with after 2 weeks. The numerical rating pain scale (NRPS), pain pressure threshold, mechanosensitivity, and Oswestry Disability Index (ODI) scores were measured before and after the intervention. Therapeutic massage and nerve stimulation therapy were performed. Lumbar flexion, extension, and rotation were performed in the movement control exercise group, whereas the sliding technique, a neurodynamic technique of the tibial nerve, was applied in the neurodynamic technique group. This effect was verified by comparing the average measured values before and after the intervention. Results: Pain (NRPS) and mechanosensitivity reduced, range of motion and tactile discrimination abilities improved, and physical function (ODI) improved. The effect of the improved intervention lasted 2 weeks. Conclusions: These results indicate that application of complex pain control programs considering the four aspects of pain mechanisms for 3 weeks can be an effective intervention in Taekwondo athletes with recurrent LBP.


Subject(s)
Low Back Pain , Martial Arts , Humans , Low Back Pain/therapy , Back Pain , Lumbosacral Region , Athletes
18.
Microsc Res Tech ; 86(9): 1099-1107, 2023 Sep.
Article in English | MEDLINE | ID: mdl-37422907

ABSTRACT

Patients with long-lasting hypertension often suffer from atrial or ventricular arrhythmias. Evidence suggests that mechanical stimulation can change the refractory period and dispersion of the ventricular myocyte action potential through stretch-activated ion channels (SACs) and influence cellular calcium transients, thus increasing susceptibility to ventricular arrhythmias. However, the specific pathogenesis of hypertension-induced arrhythmias is unknown. In this study, through clinical data, we found that a short-term increase in blood pressure leads to a rise in tachyarrhythmias in patients with clinical hypertension. We investigated the mechanism of this phenomenon using a combined imaging system(AC) of atomic force microscopy (AFM) and laser scanning confocal microscopy. After mechanical distraction to stimulate ventricular myocytes isolated from Wistar Kyoto rats (WKY) and spontaneously hypertensive rats (SHR), we synchronously monitored cardiomyocyte stiffness and intracellular calcium changes. This method can reasonably simulate cardiomyocytes' mechanics and ion changes when blood pressure rises rapidly. Our results indicated that the stiffness value of cardiomyocytes in SHR was significantly more extensive than that of normal controls, and cardiomyocytes were more sensitive to mechanical stress; In addition, intracellular calcium increased rapidly and briefly in rats with spontaneous hypertension. After intervention with streptomycin, a SAC blocker, ventricular myocytes are significantly less sensitive to mechanical stimuli. Thus, SAC is involved in developing and maintaining ventricular arrhythmias induced by hypertension. The increased stiffness of ventricular myocytes caused by hypertension leads to hypersensitivity of cellular calcium flow to mechanical stimuli is one of the mechanisms that cause arrhythmias. The AC system is a new research method to study the mechanical properties of cardiomyocytes. This study provides new techniques and ideas for developing new anti-arrhythmic drugs. HIGHLIGHT: The mechanism of hypertension-induced tachyarrhythmia is not precise. Through this study, it is found that the biophysical properties of myocardial abnormalities, the myocardium is excessively sensitive to mechanical stimulation, and the calcium flow appears to transient explosive changes, leading to tachyarrhythmia.

19.
Cells ; 12(14)2023 07 10.
Article in English | MEDLINE | ID: mdl-37508484

ABSTRACT

The hypothesis about the role of the cortical cytoskeleton as the primary mechanosensor was tested. Drosophila melanogaster oocytes were exposed to simulated microgravity (by 3D clinorotation in random directions with 4 rotations per minute-sµg group) and hypergravity at the 2 g level (by centrifugal force from one axis rotation-hg group) for 30, 90, and 210 min without and with cytochalasin B, colchicine, acrylamide, and calyculin A. Cell stiffness was measured by atomic force microscopy, protein content in the membrane and cytoplasmic fractions by Western blotting, and cellular respiration by polarography. The obtained results indicate that the stiffness of the cortical cytoskeleton of Drosophila melanogaster oocytes decreases in simulated micro- (after 90 min) and hypergravity (after 30 min), possibly due to intermediate filaments. The cell stiffness recovered after 210 min in the hg group, but intact microtubules were required for this. Already after 30 min of exposure to sµg, the cross-sectional area of oocytes decreased, which indicates deformation, and the singed protein, which organizes microfilaments into longitudinal bundles, diffused from the cortical cytoskeleton into the cytoplasm. Under hg, after 30 min, the cross-sectional area of the oocytes increased, and the proteins that organize filament networks, alpha-actinin and spectrin, diffused from the cortical cytoskeleton.


Subject(s)
Hypergravity , Mercury , Animals , Drosophila melanogaster , Cytoskeleton/metabolism , Oocytes/metabolism
20.
Curr Osteoporos Rep ; 21(4): 414-425, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37395891

ABSTRACT

PURPOSE OF REVIEW: To summarize the fundamental role of transforming growth factor beta (TGFß) signaling in osteocytes and highlight the physiological and pathophysiological conditions stemming from the deregulation of this pathway in osteocytes. RECENT FINDINGS: Osteocytes perform a myriad of skeletal and extraskeletal functions, including mechanosensing, coordinating bone remodeling, local bone matrix turnover, and maintaining systemic mineral homeostasis and global energy balance. Transforming growth factor-beta (TGFß) signaling, which is crucial for embryonic and postnatal bone development and maintenance, has been found to be essential for several osteocyte functions. There is some evidence that TGFß might be accomplishing these functions through crosstalk with the Wnt, PTH, and YAP/TAZ pathways in osteocytes, and a better understanding of this complex molecular network can help identify the pivotal convergence points responsible for distinct osteocyte functions. This review provides recent updates on the interwoven signaling cascades coordinated by TGFß signaling within osteocytes to support their skeletal and extraskeletal functions and highlights physiological and pathophysiological conditions implicating the role of TGFß signaling in osteocytes.

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