Cytoskeletal tensional homeostasis is known to be an important factor in controlling catabolic gene expression in tendon cells. Loss of cell tension in lax rat tail tendon fascicles (RTTfs) has been associated with an upregulation of MMP-13 gene expression and protein synthesis. To determine the role of the actin cytoskeleton in re-establishing tensional homeostasis in lax tendons, RTTfs were allowed to freely contract in vitro for 8 days. The cultured RTTfs contracted rapidly, reaching 50% of their initial length by 3 days. This contraction was associated with the presence of α-smooth muscle actin positive cells within the tendon. Disruption of the actin network by cytochalasian D caused an immediate and significant elongation of the contracted RTTfs. Subsequent removal of the cytochalasian D re-initiated the contraction process. When lax RTTfs were allowed to contract between fixed clamps in culture and become taut, they demonstrated a marked decrease in MMP-13 staining intensity when compared to freely contracting RTTfs. The ability of native tendon cells to contract lax tendons and re-establish their homeostatic "set point" with respect to collagenase production may be an important mechanism in the recovery of tendons elongated by injury, surgical positioning, or cyclic, viscoelastic creep secondary to repetitive exercise.
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http://dx.doi.org/10.1002/jor.22131 | DOI Listing |
Fluids Barriers CNS
January 2025
Department of Neurosurgery, Osaka Medical and Pharmaceutical University, Takatsuki, Osaka, Japan.
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View Article and Find Full Text PDFJ Transl Med
December 2024
Department of General Surgery and Surgical-Medical Specialties, Unit of Periodontology, School of Dentistry, University of Catania, Via S. Sofia 78, Catania, Catania, 95123, Italy.
Background: Micro-RNAs (miRNAs) have been reported to play an important role during orthodontic tooth movement (OTM) through the regulation of periodontal soft and hard tissue homeostasis and functions. The aim of the present study was to assess the effects of miRNAs on OTM and to evaluate possible predictors that influenced the overall OTM amount at a 3-month follow-up.
Methods: Through a split-mouth design, 21 healthy patients (mean age 13.
bioRxiv
December 2024
Department of Molecular Physiology and Biological Physics, University of Virginia; Charlottesville, VA 22903, USA.
Membranes are molecular interfaces that compartmentalize cells to control the flow of nutrients and information. These functions are facilitated by diverse collections of lipids, nearly all of which are distributed asymmetrically between the two bilayer leaflets. Most models of biomembrane structure and function often include the implicit assumption that these leaflets have similar abundances of phospholipids.
View Article and Find Full Text PDFMethods Mol Biol
December 2024
Raman Research Institute, Bangalore, Karnataka, India.
Biological cells sample their surrounding microenvironments using nanoscale force sensors on the cell surfaces. These surface-based force and stress sensors generate physical and chemical responses inside the cell. The inherently well-connected cytoskeleton and its physical contacts with the force elements on the nuclear membrane lead these physicochemical responses to cascade all the way inside the cell nucleus, physically altering the nuclear state.
View Article and Find Full Text PDFArch Biochem Biophys
December 2024
Institute for Special Environmental Biophysics, Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, 710072, Shaanxi, China. Electronic address:
Mechanical unloading can lead to homeostasis imbalance and severe muscle disease, in which muscle atrophy was one of the disused diseases. However, there were limited therapeutic targets for such diseases. In this study, miR-495 was found dramatically reduced in atrophic skeletal muscle induced by mechanical unloading models both in vitro and in vivo, including the random positioning model (RPM), tail-suspension (TS) model, and aged mice model.
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