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1.
Article in English | MEDLINE | ID: mdl-38954823

ABSTRACT

Crohn's disease (CD) is an inflammatory bowel disease characterized by transmural inflammation and intestinal fibrosis. Mechanisms of fibrosis in CD are not well understood. Transmural inflammation is associated with inflammatory cell infiltration, stenosis, and distention, which present mechanical stress (MS) to the bowel wall. We hypothesize that MS induces gene expression of pro-fibrotic mediators such as connective tissue growth factor (CTGF), which may contribute to fibrosis in CD. A rodent model of CD was induced by intracolonic instillation of TNBS to the distal colon. TNBS instillation induced a localized transmural inflammation (site I), with a distended colon segment (site P) proximal to site I. We detected significant fibrosis and collagen content not only in site I, but also in site P in CD rats by day 7. CTGF expression increased significantly in sites P and I, but not in the segment distal to the inflammation site. Increased CTGF expression was detected mainly in the smooth muscle cells (SMC). When rats were fed exclusively with clear liquid diet to prevent mechanical distention in colitis, expression of CTGF in sites P and I was blocked. Direct stretch led to robust expression of CTGF in colonic SMC. Treatment of CD rats with anti-CTGF antibody FG-3149 reduced fibrosis and collagen content in both sites P and I and exhibited consistent trends towards normalizing expression of collagen mRNAs. In conclusion, our studies suggest that mechanical stress, by up-regulating pro-fibrotic mediators i.e. CTGF, may play a critical role in fibrosis in CD.

2.
J Orthop Surg Res ; 19(1): 385, 2024 Jul 01.
Article in English | MEDLINE | ID: mdl-38951850

ABSTRACT

BACKGROUND: In recent years, the use of tapered-wedge short stems has increased due to their ability to preserve bones and tendons. Surgical techniques occasionally result in a varus position of the stem, which is particularly pronounced in short stems. Although the varus position is not clinically problematic, there are reports of an increased incidence of stress shielding and cortical hypertrophy. Thus, we evaluated and examined the acceptable range of varus angles using finite element analysis. METHODS: Patients diagnosed with osteoarthritis of the hip joint who had undergone arthroplasty were selected and classified into three types [champagne-flute (type A), intermediate (type B), and stovepipe (type C)]. Finite element analysis was performed using Mechanical Finder. The model was created using a Taperloc microplasty stem with the varus angle increased by 1° from 0° to 5° from the bone axis and classified into seven zones based on Gruen's zone classification under loading conditions in a one-leg standing position. The volume of interest was set, the mean equivalent stress for each zone was calculated. RESULTS: A significant decrease in stress was observed in zone 2, and increased stress was observed in zones 3 and 4, suggesting the emergence of a distal periosteal reaction, similar to the results of previous studies. In zone 2, there was a significant decrease in stress in all groups at a varus angle ≥ 3°. In zone 3, stress increased from ≥ 3° in type B and ≥ 4° in type C. In zone 4, there was a significant increase in stress at varus angles of ≥ 2° in types A and B and at ≥ 3° in type C. CONCLUSION: In zone 2, the varus angle at which stress shielding above Engh classification grade 3 may appear is expected to be ≥ 3°. Distal cortical hypertrophy may appear in zones 3 and 4; the narrower the medullary cavity shape, the smaller the allowable angle of internal recession, and the wider the medullary cavity shape, the wider the allowable range. Long-term follow-up is required in patients with varus angles > 3°.


Subject(s)
Arthroplasty, Replacement, Hip , Finite Element Analysis , Hip Prosthesis , Stress, Mechanical , Humans , Arthroplasty, Replacement, Hip/methods , Male , Female , Prosthesis Design , Aged , Osteoarthritis, Hip/surgery , Osteoarthritis, Hip/diagnostic imaging , Middle Aged
3.
Proc Natl Acad Sci U S A ; 121(29): e2404551121, 2024 Jul 16.
Article in English | MEDLINE | ID: mdl-38990945

ABSTRACT

Confined cell migration hampers genome integrity and activates the ATR and ATM mechano-transduction pathways. We investigated whether the mechanical stress generated by metastatic interstitial migration contributes to the enhanced chromosomal instability observed in metastatic tumor cells. We employed live cell imaging, micro-fluidic approaches, and scRNA-seq to follow the fate of tumor cells experiencing confined migration. We found that, despite functional ATR, ATM, and spindle assembly checkpoint (SAC) pathways, tumor cells dividing across constriction frequently exhibited altered spindle pole organization, chromosome mis-segregations, micronuclei formation, chromosome fragility, high gene copy number variation, and transcriptional de-regulation and up-regulation of c-MYC oncogenic transcriptional signature via c-MYC locus amplifications. In vivo tumor settings showed that malignant cells populating metastatic foci or infiltrating the interstitial stroma gave rise to cells expressing high levels of c-MYC. Altogether, our data suggest that mechanical stress during metastatic migration contributes to override the checkpoint controls and boosts genotoxic and oncogenic events. Our findings may explain why cancer aneuploidy often does not correlate with mutations in SAC genes and why c-MYC amplification is strongly linked to metastatic tumors.


Subject(s)
Cell Movement , Gene Amplification , Proto-Oncogene Proteins c-myc , Stress, Mechanical , Humans , Cell Movement/genetics , Proto-Oncogene Proteins c-myc/metabolism , Proto-Oncogene Proteins c-myc/genetics , Animals , Cell Line, Tumor , Mice , Mitosis/genetics , Chromosomal Instability , Gene Expression Regulation, Neoplastic , Neoplasms/genetics , Neoplasms/pathology , Neoplasms/metabolism
4.
Proc Natl Acad Sci U S A ; 121(29): e2320470121, 2024 Jul 16.
Article in English | MEDLINE | ID: mdl-38990951

ABSTRACT

Although the formation of new walls during plant cell division tends to follow maximal tensile stress direction, analyses of individual cells over time reveal a much more variable behavior. The origin of such variability as well as the exact role of interphasic microtubule behavior before cell division have remained mysterious so far. To approach this question, we took advantage of the Arabidopsis stem, where the tensile stress pattern is both highly anisotropic and stable. Although cortical microtubules (CMTs) generally align with maximal tensile stress, we detected a specific time window, ca. 3 h before cell division, where cells form a radial pattern of CMTs. This microtubule array organization preceded preprophase band (PPB) formation, a transient CMT array predicting the position of the future division plane. It was observed under different growth conditions and was not related to cell geometry or polar auxin transport. Interestingly, this cortical radial pattern correlated with the well-documented increase of cytoplasmic microtubule accumulation before cell division. This radial organization was prolonged in cells of the trm678 mutant, where CMTs are unable to form a PPB. Whereas division plane orientation in trm678 is noisier, we found that cell division symmetry was in contrast less variable between daughter cells. We propose that this "radial step" reflects a trade-off in robustness for two essential cell division attributes: symmetry and orientation. This involves a "reset" stage in G2, where an increased cytoplasmic microtubule accumulation transiently disrupts CMT alignment with tissue stress.


Subject(s)
Arabidopsis Proteins , Arabidopsis , Cell Division , Microtubules , Arabidopsis/metabolism , Arabidopsis/cytology , Microtubules/metabolism , Cell Division/physiology , Arabidopsis Proteins/metabolism , Arabidopsis Proteins/genetics , Indoleacetic Acids/metabolism
5.
FASEB J ; 38(13): e23776, 2024 Jul 15.
Article in English | MEDLINE | ID: mdl-38958998

ABSTRACT

This study aimed to explore how mechanical stress affects osteogenic differentiation via the miR-187-3p/CNR2 pathway. To conduct this study, 24 female C57BL/6 mice, aged 8 weeks, were used and divided into four groups. The Sham and OVX groups did not undergo treadmill exercise, while the Sham + EX and OVX + EX groups received a 8-week treadmill exercise. Post-training, bone marrow and fresh femur samples were collected for further analysis. Molecular biology analysis, histomorphology analysis, and micro-CT analysis were conducted on these samples. Moreover, primary osteoblasts were cultured under osteogenic conditions and divided into GM group and CTS group. The cells in the CTS group underwent a sinusoidal stretching regimen for either 3 or 7 days. The expression of early osteoblast markers (Runx2, OPN, and ALP) was measured to assess differentiation. The study findings revealed that mechanical stress has a regulatory impact on osteoblast differentiation. The expression of miR-187-3p was observed to decrease, facilitating osteogenic differentiation, while the expression of CNR2 increased significantly. These observations suggest that mechanical stress, miR-187-3p, and CNR2 play crucial roles in regulating osteogenic differentiation. Both in vivo and in vitro experiments have confirmed that mechanical stress downregulates miR-187-3p and upregulates CNR2, which leads to the restoration of distal femoral bone mass and enhancement of osteoblast differentiation. Therefore, mechanical stress promotes osteoblasts, resulting in improved osteoporosis through the miR-187-3p/CNR2 signaling pathway. These findings have broad prospect and provide molecular biology guidance for the basic research and clinical application of exercise in the prevention and treatment of PMOP.


Subject(s)
Cell Differentiation , Mice, Inbred C57BL , MicroRNAs , Osteoblasts , Osteogenesis , Osteoporosis, Postmenopausal , Stress, Mechanical , Animals , MicroRNAs/genetics , MicroRNAs/metabolism , Osteoblasts/metabolism , Female , Osteoporosis, Postmenopausal/metabolism , Osteoporosis, Postmenopausal/therapy , Osteoporosis, Postmenopausal/genetics , Osteoporosis, Postmenopausal/pathology , Mice , Osteogenesis/physiology , Humans , Signal Transduction , Cells, Cultured
6.
Stem Cell Rev Rep ; 2024 Jun 07.
Article in English | MEDLINE | ID: mdl-38848014

ABSTRACT

Non-coding RNA has many types which has rich functions and plays an important role in the study of basic molecular mechanisms. Many non-coding RNA have important implications for pluripotent stem cells and embryonic stem cells. It has been found to affect the self-renewal and osteogenesis of many types of stem cells. They have also been found to regulate stem cell proliferation and induct bone differentiation. Periodontal ligament stem cells are essential for the regeneration of periodontal tissue. In recent years, in the field of stomatology, studies have found that many non-coding RNA also have significant regulatory effects on the proliferation and differentiation of periodontal stem cells and may become potential therapeutic targets for many common periodontal diseases such as periodontitis, bone/tooth/soft tissue loss and orthodontic treatment. Therefore, we summarized the current research status of non-coding RNA in the field of molecular mechanism of periodontal ligament stem cells and prospected its future progress.

7.
Ultrasonics ; 142: 107374, 2024 Jun 06.
Article in English | MEDLINE | ID: mdl-38875881

ABSTRACT

This study investigates the size-dependent dynamics of bubbles and their interaction with soft boundaries under various ultrasound (US) conditions. We found that bubble behavior is influenced by size, with smaller bubbles displaying reduced inertial motion in similar ultrasound environments. Detailed analyses of three bubble sizes (1.5 µm, 15 µm, and 150 µm) next to a soft 1 kPa boundary revealed distinct patterns in radial oscillation, bubble center displacement, and boundary deflection for different ultrasound frequencies (5 kHz - 4 MHz). The smallest bubble maintained a spherical shape, while the largest experienced significant shape changes, indicative of impending jet formation. Investigating interactions at various frequencies highlighted the collapse tendency of the larger bubbles, showcasing maximum radial amplitude, displacement, and bubble wall velocity around its natural frequency. The presence of a soft boundary minimally affected radial amplitude and velocity, while the bubble displacement was contingent on the soft boundary modulus. Furthermore, boundary responses demonstrated that softer boundaries experienced less stress during bubble oscillations, exhibiting sharper peaks at resonance frequencies for larger bubbles. These findings provide valuable insights into optimizing ultrasound conditions for a variety of applications, highlighting the influence of bubble size and boundary properties on outcomes.

8.
Nano Lett ; 2024 Jun 25.
Article in English | MEDLINE | ID: mdl-38916205

ABSTRACT

Mechanical stress significantly affects the physiological functions of cells, including tissue homeostasis, cytoskeletal alterations, and intracellular transport. As a major cytoskeletal component, microtubules respond to mechanical stimulation by altering their alignment and polymerization dynamics. Previously, we reported that microtubules may modulate cargo transport by one of the microtubule-associated motor proteins, dynein, under compressive mechanical stress. Despite the critical role of tensile stress in many biological functions, how tensile stress on microtubules regulates cargo transport is yet to be unveiled. The present study demonstrates that the low-level tensile stress-induced microtubule deformation facilitates dynein-driven transport. We validate our experimental findings using all-atom molecular dynamics simulation. Our study may provide important implications for developing new therapies for diseases that involve impaired intracellular transport.

9.
Front Immunol ; 15: 1385006, 2024.
Article in English | MEDLINE | ID: mdl-38895122

ABSTRACT

Osteoarthritis (OA) is the most common form of arthritis, characterized by osteophyte formation, cartilage degradation, and structural and cellular alterations of the synovial membrane. Activated fibroblast-like synoviocytes (FLS) of the synovial membrane have been identified as key drivers, secreting humoral mediators that maintain inflammatory processes, proteases that cause cartilage and bone destruction, and factors that drive fibrotic processes. In normal tissue repair, fibrotic processes are terminated after the damage has been repaired. In fibrosis, tissue remodeling and wound healing are exaggerated and prolonged. Various stressors, including aging, joint instability, and inflammation, lead to structural damage of the joint and micro lesions within the synovial tissue. One result is the reduced production of synovial fluid (lubricants), which reduces the lubricity of the cartilage areas, leading to cartilage damage. In the synovial tissue, a wound-healing cascade is initiated by activating macrophages, Th2 cells, and FLS. The latter can be divided into two major populations. The destructive thymocyte differentiation antigen (THY)1─ phenotype is restricted to the synovial lining layer. In contrast, the THY1+ phenotype of the sublining layer is classified as an invasive one with immune effector function driving synovitis. The exact mechanisms involved in the transition of fibroblasts into a myofibroblast-like phenotype that drives fibrosis remain unclear. The review provides an overview of the phenotypes and spatial distribution of FLS in the synovial membrane of OA, describes the mechanisms of fibroblast into myofibroblast activation, and the metabolic alterations of myofibroblast-like cells.


Subject(s)
Fibroblasts , Fibrosis , Osteoarthritis , Phenotype , Synoviocytes , Humans , Osteoarthritis/pathology , Osteoarthritis/immunology , Osteoarthritis/metabolism , Fibroblasts/metabolism , Fibroblasts/pathology , Fibroblasts/immunology , Animals , Synoviocytes/metabolism , Synoviocytes/pathology , Synoviocytes/immunology , Synovial Membrane/pathology , Synovial Membrane/immunology , Synovial Membrane/metabolism
10.
J Oral Biosci ; 2024 Jun 25.
Article in English | MEDLINE | ID: mdl-38936470

ABSTRACT

OBJECTIVES: The present study aimed to elucidate the pathogenesis of temporomandibular joint (TMJ) osteoarthritis (TMJ-OA) in a mouse model. We investigated morphological and histological changes in the head of mandible cartilage and early immunohistochemical (IHC) changes in transforming growth factor (TGF)-ß, phosphorylated Smad-2/3 (p-Smad2/3), a TGF-ß signaling molecule, and asporin. METHODS: TMJ-OA was induced in a mouse model through unilateral partial discectomy. Micro-computed tomography (micro-CT) and safranin-O staining were performed to morphologically and histologically evaluate the degeneration of the head of mandible caused by TMJ-OA. IHC staining for TGF-ß, p-Smad2/3, and asporin was performed to evaluate the changes in protein expression. RESULTS: In the experimental group, three-dimensional (3D) morphometry revealed an enlarged head of mandible and safranin-O staining showed degeneration of cartilage tissue in the early stages of TMJ-OA compared to the control group. IHC staining revealed that TGF-ß, p-Smad2/3, and asporin expression increased in the head of mandible cartilage before the degeneration of cartilage tissue, and subsequently decreased for a short period. CONCLUSION: The findings suggested a negative feedback relationship between the expression of asporin and the TGF-ß/Smad transduction pathway, which may be involved in the degeneration of the head of mandible in the early stages of TMJ-OA. Asporin is a potential biomarker of the early stages of TMJ-OA, which ultimately leads to the irreversible degeneration of TMJ tissues.

11.
Cureus ; 16(5): e59429, 2024 May.
Article in English | MEDLINE | ID: mdl-38827003

ABSTRACT

Thoracic ossification of the ligamentum flavum (OLF) is known to result in spinal canal stenosis and myelopathy. It is typically treated through decompressive laminectomy and resection of the ossified ligament, which is known to improve neurological deficits. However, the recurrence of OLF post-surgery remains a relatively undocumented and complex issue. The present report describes the case of a 58-year-old male patient who had obesity (BMI 34), diabetes mellitus, and Basedow's disease. The patient presented with bilateral lower limb paresthesia and associated gait impairment, resulting in an urgent hospital admission. Imaging diagnostics identified extensive thoracic ossification of the posterior longitudinal ligament and OLF, both of which resulted in significant spinal cord compression. He underwent posterior decompression with instrumented fusion from T1 to T9 and additional laminectomy and OLF resection at T10/11. Despite an initial improvement in the postoperative period, the patient developed an epidural hematoma one week following surgery, causing significant paralysis of the lower limbs. This complication was promptly addressed with hematoma removal surgery. Six months after the initial procedure, his walking function improved significantly, but eight months after surgery, he experienced a sudden regression in motor functions due to the recurrence of OLF at T10/11, necessitating an additional posterior instrumented fusion surgery. Subsequent to the additional surgical procedure, the patient experienced an amelioration in paralysis, enabling him to ambulate with the aid of a cane. The recurrence of thoracic OLF after decompression surgery is a significant concern, especially in cases where decompression without instrumented fusion is performed. When determining the surgical procedure for thoracic OLF in cases with extensive ossification of the spinal ligaments, it is crucial to consider the degree of spontaneous fusion and mobility of the spinal segments, as demonstrated in the present case. The concentration of mechanical stress due to fusion at adjacent segments and intervertebral mobility at the thoracolumbar junction may increase the risk of OLF recurrence and should be carefully assessed preoperatively, even though posterior decompression surgery is typically considered a sufficient option for thoracic OLF.

12.
Int J Paleopathol ; 46: 1-8, 2024 Jun 05.
Article in English | MEDLINE | ID: mdl-38843611

ABSTRACT

OBJECTIVE: This study explores the interplay between age-at-death, sex and occupation and the presence, location and severity of Schmorl's nodes. MATERIALS: Vertebral columns of 327 individuals, 180 (55.1%) males and 147 (44.9%) females, with age-at-death between 20 and 65 years old, with known occupation. METHODS: Schmorl's nodes were recorded as present/absent and by location and severity. RESULTS: In this sample, 58.7% (192/327) of individuals were affected by Schmorl's nodes, 75.6% (136/180) were males and 38.1% (56/147) were females, with statistically significant differences (p=0.000). Schmorl's nodes were most commonly found on the T7-L2 (77.1% of all Schmorl's nodes) vertebrae and at the center (73.4%) of the vertebral body surface. Age and occupational categories did not correlate with prevalence, quantity or severity. CONCLUSIONS: Males appear more prone to develop Schmorl's nodes than females. In this study, the prevalence of Schmorl's nodes does not increase with age, nor with the type of occupation held by males. SIGNIFICANCE: This study rejects the purported associations between prevalence of Schmorl's nodes and age and physical stress. LIMITATIONS: It is unknown whether individuals had the same occupation throughout their lives or for how long they performed it. Additionally, it is impossible to access when the individual developed the Schmorl's node. SUGGESTIONS FOR FURTHER RESEARCH: Evaluate the onset of Schmorl's nodes in individuals under 20 and explore possible links between vertebral morphology and the occurrence of Schmorl's nodes.

13.
Int J Mol Sci ; 25(11)2024 May 21.
Article in English | MEDLINE | ID: mdl-38891788

ABSTRACT

In the process of tissue engineering, several types of stresses can influence the outcome of tissue regeneration. This outcome can be understood by designing hydrogels that mimic this process and studying how such hydrogel scaffolds and cells behave under a set of stresses. Here, a hydrogel formulation is proposed to create biomimetic scaffolds suitable for fibroblast cell culture. Subsequently, we examine the impact of external stresses on fibroblast cells cultured on both solid and porous hydrogels. These stresses included mechanical tension and altered-gravity conditions experienced during the 83rd parabolic flight campaign conducted by the European Space Agency. This study shows distinct cellular responses characterized by cell aggregation and redistribution in regions of intensified stress concentration. This paper presents a new biomimetic hydrogel that fulfills tissue-engineering requirements in terms of biocompatibility and mechanical stability. Moreover, it contributes to our comprehension of cellular biomechanics under diverse gravitational conditions, shedding light on the dynamic cellular adaptations versus varying stress environments.


Subject(s)
Fibroblasts , Hydrogels , Tissue Engineering , Fibroblasts/drug effects , Fibroblasts/metabolism , Fibroblasts/cytology , Hydrogels/chemistry , Tissue Engineering/methods , Cell Culture Techniques/methods , Stress, Mechanical , Biomimetics/methods , Animals , Tissue Scaffolds/chemistry , Biomimetic Materials/chemistry , Biomimetic Materials/pharmacology , Humans , Mice
14.
Biochim Biophys Acta Mol Basis Dis ; 1870(6): 167265, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38810918

ABSTRACT

Cataract is the leading cause of blindness across the world. Age-related cataract (ARC) is the most common type of cataract, but its pathogenesis is not fully understood. Using three-dimensional finite element modeling combining experimental biotechnology, our study demonstrates that external forces during accommodation cause mechanical stress predominantly in lens cortex, basically matching the localization of opacities in cortical ARCs. We identified the cellular senescence and upregulation of PIEZO1 mRNA in HLECs under mechanical stretch. This mechano-induced senescence in HLECs might be mediated by PIEZO1-related pathways, portraying a potential biomechanical cause of cortical ARCs. Our study updates the fundamental insight towards cataractogenesis, paving the way for further exploration of ARCs pathogenesis and nonsurgical treatment.


Subject(s)
Cataract , Finite Element Analysis , Lens, Crystalline , Stress, Mechanical , Humans , Cataract/genetics , Cataract/pathology , Lens, Crystalline/metabolism , Lens, Crystalline/pathology , Ion Channels/genetics , Ion Channels/metabolism , RNA-Seq , Aging/genetics , Aging/pathology , Cellular Senescence/genetics
15.
Arterioscler Thromb Vasc Biol ; 44(7): 1617-1627, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38721707

ABSTRACT

BACKGROUND: While it has been hypothesized that high plaque stress and strain may be related to plaque rupture, its direct verification using in vivo coronary plaque rupture data and full 3-dimensional fluid-structure interaction models is lacking in the current literature due to difficulty in obtaining in vivo plaque rupture imaging data from patients with acute coronary syndrome. This case-control study aims to use high-resolution optical coherence tomography-verified in vivo plaque rupture data and 3-dimensional fluid-structure interaction models to seek direct evidence for the high plaque stress/strain hypothesis. METHODS: In vivo coronary plaque optical coherence tomography data (5 ruptured plaques, 5 no-rupture plaques) were acquired from patients using a protocol approved by the local institutional review board with informed consent obtained. The ruptured caps were reconstructed to their prerupture morphology using neighboring plaque cap and vessel geometries. Optical coherence tomography-based 3-dimensional fluid-structure interaction models were constructed to obtain plaque stress, strain, and flow shear stress data for comparative analysis. The rank-sum test in the nonparametric test was used for statistical analysis. RESULTS: Our results showed that the average maximum cap stress and strain values of ruptured plaques were 142% (457.70 versus 189.22 kPa; P=0.0278) and 48% (0.2267 versus 0.1527 kPa; P=0.0476) higher than that for no-rupture plaques, respectively. The mean values of maximum flow shear stresses for ruptured and no-rupture plaques were 145.02 dyn/cm2 and 81.92 dyn/cm2 (P=0.1111), respectively. However, the flow shear stress difference was not statistically significant. CONCLUSIONS: This preliminary case-control study showed that the ruptured plaque group had higher mean maximum stress and strain values. Due to our small study size, larger scale studies are needed to further validate our findings.


Subject(s)
Coronary Artery Disease , Coronary Vessels , Plaque, Atherosclerotic , Stress, Mechanical , Tomography, Optical Coherence , Humans , Coronary Vessels/diagnostic imaging , Coronary Vessels/physiopathology , Coronary Vessels/pathology , Rupture, Spontaneous , Case-Control Studies , Coronary Artery Disease/diagnostic imaging , Coronary Artery Disease/physiopathology , Male , Female , Middle Aged , Models, Cardiovascular , Aged , Predictive Value of Tests , Acute Coronary Syndrome/diagnostic imaging , Acute Coronary Syndrome/physiopathology , Acute Coronary Syndrome/etiology
16.
Sci Bull (Beijing) ; 69(12): 1964-1979, 2024 Jun 30.
Article in English | MEDLINE | ID: mdl-38760248

ABSTRACT

Mechanical loading is required for bone homeostasis, but the underlying mechanism is still unclear. Our previous studies revealed that the mechanical protein polycystin-1 (PC1, encoded by Pkd1) is critical for bone formation. However, the role of PC1 in bone resorption is unknown. Here, we found that PC1 directly regulates osteoclastogenesis and bone resorption. The conditional deletion of Pkd1 in the osteoclast lineage resulted in a reduced number of osteoclasts, decreased bone resorption, and increased bone mass. A cohort study of 32,500 patients further revealed that autosomal dominant polycystic kidney disease, which is mainly caused by loss-of-function mutation of the PKD1 gene, is associated with a lower risk of hip fracture than those with other chronic kidney diseases. Moreover, mice with osteoclast-specific knockout of Pkd1 showed complete resistance to unloading-induced bone loss. A mechanistic study revealed that PC1 facilitated TAZ nuclear translocation via the C-terminal tail-TAZ complex and that conditional deletion of Taz in the osteoclast lineage resulted in reduced osteoclastogenesis and increased bone mass. Pharmacological regulation of the PC1-TAZ axis alleviated unloading- and estrogen deficiency- induced bone loss. Thus, the PC1-TAZ axis may be a potential therapeutic target for osteoclast-related osteoporosis.


Subject(s)
Bone Resorption , Mice, Knockout , Osteoclasts , Osteogenesis , TRPP Cation Channels , Animals , TRPP Cation Channels/genetics , TRPP Cation Channels/metabolism , Bone Resorption/metabolism , Bone Resorption/genetics , Bone Resorption/pathology , Osteoclasts/metabolism , Mice , Humans , Osteoporosis/genetics , Osteoporosis/metabolism , Osteoporosis/pathology , Polycystic Kidney, Autosomal Dominant/genetics , Polycystic Kidney, Autosomal Dominant/metabolism , Polycystic Kidney, Autosomal Dominant/pathology , Male , Female , Adaptor Proteins, Signal Transducing
17.
Int J Mol Sci ; 25(10)2024 May 13.
Article in English | MEDLINE | ID: mdl-38791359

ABSTRACT

The excessive activation of frog eggs, referred to as overactivation, can be initiated by strong oxidative stress, leading to expedited calcium-dependent non-apoptotic cell death. Overactivation also occurs spontaneously, albeit at a low frequency, in natural populations of spawned frog eggs. Currently, the cytological and biochemical events of the spontaneous process have not been characterized. In the present study, we demonstrate that the spontaneous overactivation of Xenopus frog eggs, similarly to oxidative stress- and mechanical stress-induced overactivation, is characterized by the fast and irreversible contraction of the egg's cortical layer, an increase in egg size, the depletion of intracellular ATP, a drastic increase in the intracellular ADP/ATP ratio, and the degradation of M phase-specific cyclin B2. These events manifest in eggs in the absence of caspase activation within one hour of triggering overactivation. Importantly, substantial amounts of ATP and ADP leak from the overactivated eggs, indicating that plasma membrane integrity is compromised in these cells. The rupture of the plasma membrane and acute depletion of intracellular ATP explicitly define necrotic cell death. Finally, we report that egg overactivation can occur in the frog's genital tract. Our data suggest that mechanical stress may be a key factor promoting egg overactivation during oviposition in frogs.


Subject(s)
Adenosine Triphosphate , Necrosis , Ovum , Animals , Adenosine Triphosphate/metabolism , Ovum/metabolism , Xenopus laevis/metabolism , Female , Oxidative Stress , Adenosine Diphosphate/metabolism , Cell Death , Cell Membrane/metabolism , Stress, Mechanical
18.
Nanotechnology ; 35(33)2024 May 30.
Article in English | MEDLINE | ID: mdl-38759631

ABSTRACT

In this paper, the piezoresistive sensitivity is enhanced by applying uniform mechanical stress (MS) on the multi-nanosheet (NS) channels of sub-5 nm junctionless field-effect transistors. The piezoresistivity of the sensing device is boosted by narrowing channel conductivity using low gate biasing and reducing physical channel width, resulting in the maximum (∼6 times higher) sensitivity observed in the subthreshold regime compared to the ON-state condition. In addition, the sensitivity is extensively increased by ∼30.3% near the threshold voltage with horizontally multi-NS stacking due to the uniform MS distribution on the multi-NS channels, which can sense slight deflection of pressure on the circular diaphragm. These results show that the tunable sensitivity of junctionless multi-channel devices is superior to the inversion mode, a consequence of the less scattering effect, better thermal stability, and low electronic noise.

19.
Phys Life Rev ; 49: 77-94, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38564907

ABSTRACT

Mechanical stress stands as a fundamental factor in the intricate processes governing the growth, development, morphological shaping, and maintenance of skeletal mass. The profound influence of stress in shaping the skeletal framework prompts the assertion that stress essentially births the skeleton. Despite this acknowledgment, the mechanisms by which the skeleton perceives and responds to mechanical stress remain enigmatic. In this comprehensive review, our scrutiny focuses on the structural composition and characteristics of sclerotin, leading us to posit that it serves as the primary structure within the skeleton responsible for bearing and perceiving mechanical stress. Furthermore, we propose that osteocytes within the sclerotin emerge as the principal mechanical-sensitive cells, finely attuned to perceive mechanical stress. And a detailed analysis was conducted on the possible transmission pathways of mechanical stress from the extracellular matrix to the nucleus.


Subject(s)
Stress, Mechanical , Humans , Animals , Osteocytes , Bone and Bones , Extracellular Matrix
20.
Front Immunol ; 15: 1342895, 2024.
Article in English | MEDLINE | ID: mdl-38566997

ABSTRACT

Excessive fibrous capsule formation around silicone mammary implants (SMI) involves immune reactions to silicone. Capsular fibrosis, a common SMI complication linked to host responses, worsens with specific implant topographies. Our study with 10 patients investigated intra- and inter-individually, reduced surface roughness effects on disease progression, wound responses, chronic inflammation, and capsular composition. The results illuminate the significant impact of surface roughness on acute inflammatory responses, fibrinogen accumulation, and the subsequent fibrotic cascade. The reduction of surface roughness to an average roughness of 4 µm emerges as a promising approach for mitigating detrimental immune reactions, promoting healthy wound healing, and curbing excessive fibrosis. The identified proteins adhering to rougher surfaces shed light on potential mediators of pro-inflammatory and pro-fibrotic processes, further emphasizing the need for meticulous consideration of surface design. The composition of the implant capsule and the discovery of intracapsular HSP60 expression highlight the intricate web of stress responses and immune activation that can impact long-term tissue outcomes.


Subject(s)
Inflammation , Prostheses and Implants , Humans , Silicones , Fibrosis , Wound Healing
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