Mechanosensory ion channels are proteins that are sensitive to mechanical forces. They are found in tissues throughout the body and play an important role in bone remodeling by sensing changes in mechanical stress and transmitting signals to bone-forming cells. Orthodontic tooth movement (OTM) is a prime example of mechanically induced bone remodeling. However, the cell-specific role of the ion channels Piezo1 and Piezo2 in OTM has not been investigated yet. Here we first identify the expression of PIEZO1/2 in the dentoalveolar hard tissues. Results showed that PIEZO1 was expressed in odontoblasts, osteoblasts, and osteocytes, while PIEZO2 was localized in odontoblasts and cementoblasts. We therefore used a Piezo1floxed/floxed mouse model in combination with Dmp1cre to inactivate Piezo1 in mature osteoblasts/cementoblasts, osteocytes/cementocytes, and odontoblasts. Inactivation of Piezo1 in these cells did not affect the overall morphology of the skull but caused significant bone loss in the craniofacial skeleton. Histological analysis revealed a significantly increased number of osteoclasts in Piezo1floxed/floxed;Dmp1cre mice, while osteoblasts were not affected. Despite this increased number of osteoclasts, orthodontic tooth movement was not altered in these mice. Our results suggest that despite Piezo1 being crucial for osteoclast function, it may be dispensable for mechanical sensing of bone remodeling.

• MeSH
• buňky pojivové tkáně * MeSH
• iontové kanály MeSH
• myši MeSH
• osteoblasty * MeSH
• osteocyty MeSH
• osteoklasty MeSH
• remodelace kosti MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• iontové kanály MeSH
• Piezo1 protein, mouse MeSH Prohlížeč

Estrogen is known to regulate bone metabolism in both women and men, but substantial gaps remain in our knowledge of estrogen and estrogen receptor alpha (ERα) regulation of adult bone metabolism. Studies using global ERα-knockout mice were confounded by high circulating sex-steroid levels, and osteocyte/osteoblast-specific ERα deletion may be confounded by ERα effects on growth versus the adult skeleton. Thus, we developed mice expressing the tamoxifen-inducible CreERT2 in osteocytes using the 8-kilobase (kb) Dmp1 promoter (Dmp1CreERT2 ). These mice were crossed with ERαfl//fl mice to create ERαΔOcy mice, permitting inducible osteocyte-specific ERα deletion in adulthood. After intermittent tamoxifen treatment of adult 4-month-old mice for 1 month, female, but not male, ERαΔOcy mice exhibited reduced spine bone volume fraction (BV/TV (-20.1%, p = 0.004) accompanied by decreased trabecular bone formation rate (-18.9%, p = 0.0496) and serum P1NP levels (-38.9%, p = 0.014). Periosteal (+65.6%, p = 0.004) and endocortical (+64.1%, p = 0.003) expansion were higher in ERαΔOcy mice compared to control (Dmp1CreERT2 ) mice at the tibial diaphysis, reflecting the known effects of estrogen to inhibit periosteal apposition and promote endocortical formation. Increases in Sost (2.1-fold, p = 0.001) messenger RNA (mRNA) levels were observed in trabecular bone at the spine in ERαΔOcy mice, consistent with previous reports that estrogen deficiency is associated with increased circulating sclerostin as well as bone SOST mRNA levels in humans. Further, the biological consequences of increased Sost expression were reflected in significant overall downregulation in panels of osteoblast and Wnt target genes in osteocyte-enriched bones from ERαΔOcy mice. These findings thus establish that osteocytic ERα is critical for estrogen action in female, but not male, adult bone metabolism. Moreover, the reduction in bone formation accompanied by increased Sost, decreased osteoblast, and decreased Wnt target gene expression in ERαΔOcy mice provides a direct link in vivo between ERα and Wnt signaling. © 2022 American Society for Bone and Mineral Research (ASBMR).

• Klíčová slova
• ESTROGENS AND SERMs, GENETIC ANIMAL MODELS, OSTEOCYTES, OSTEOPOROSIS, SEX STEROIDS,
• MeSH
• adaptorové proteiny signální transdukční metabolismus   MeSH
• alfa receptor estrogenů * genetika   metabolismus   MeSH
• dospělí MeSH
• estrogeny metabolismus   farmakologie   MeSH
• kojenec MeSH
• lidé MeSH
• messenger RNA metabolismus   MeSH
• mezibuněčné signální peptidy a proteiny metabolismus   MeSH
• myši knockoutované MeSH
• myši MeSH
• osteoblasty metabolismus   MeSH
• osteocyty * metabolismus   MeSH
• tamoxifen farmakologie   MeSH
• zvířata MeSH
• Check Tag
• dospělí MeSH
• kojenec MeSH
• lidé MeSH
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• adaptorové proteiny signální transdukční MeSH
• alfa receptor estrogenů * MeSH
• estrogeny MeSH
• messenger RNA MeSH
• mezibuněčné signální peptidy a proteiny MeSH
• tamoxifen MeSH

It is primarily important to define the standard features and factors that affect dental pulp stem cells (DPSCs) for their broader use in tissue engineering. This study aimed to verify whether DPSCs isolated from various teeth extracted from the same donor exhibit intra-individual variability and what the consequences are for their differentiation potential. The heterogeneity determination was based on studying the proliferative capacity, viability, expression of phenotypic markers, and relative length of telomere chromosomes. The study included 14 teeth (6 molars and 8 premolars) from six different individuals ages 12 to 16. We did not observe any significant intra-individual variability in DPSC size, proliferation rate, viability, or relative telomere length change within lineages isolated from different teeth but the same donor. The minor non-significant variances in phenotype were probably mainly because DPSC cell lines comprised heterogeneous groups of undifferentiated cells independent of the donor. The other variances were seen in DPSC lineages isolated from the same donor, but the teeth were in different stages of root development. We also did not observe any changes in the ability of cells to differentiate into mature cell lines-chondrocytes, osteocytes, and adipocytes. This study is the first to analyze the heterogeneity of DPSC dependent on a donor.

• Klíčová slova
• dental stem cells, intra-individual variability, mesenchymal stem cells, regenerative medicine, same donor isolation, stem cell characterization,
• MeSH
• buněčná diferenciace fyziologie   MeSH
• buněčné linie MeSH
• buněčný rodokmen fyziologie   MeSH
• chondrocyty fyziologie   MeSH
• dárci tkání MeSH
• individuální biologická variabilita MeSH
• kmenové buňky fyziologie   MeSH
• lidé MeSH
• mladiství MeSH
• osteocyty fyziologie   MeSH
• proliferace buněk fyziologie   MeSH
• tukové buňky fyziologie   MeSH
• zubní dřeň fyziologie   MeSH
• Check Tag
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

The purpose of this study was to investigate the effect of load-induced local mechanical strain on bone cell activity of peri-implant bone in mice. Titanium implants were placed in the maxillae of 13-week-old male C57BL/6J mice and subjected to intermittent 0.15 N, 0.3 N, or 0.6 N loads for 30 min/day for 6 days. The animals were sacrificed 2 days after the final loading. Unloaded mice were used as controls. An animal-specific three-dimensional finite element model was constructed based on morphological data retrieved from in vivo microfocus computed tomography for each mouse to calculate the mechanical strain distribution. Strain distribution images were overlaid on corresponding histological images of the same site in the same animal. The buccal cervical region of the peri-implant bone was predetermined as the region of interest (ROI). Each ROI was divided by four strain intensity levels: 0-20 με, 20-60 με, 60-100 με, and ≥100 με, and the bone histomorphometric parameters were analyzed by the total area of each strain range for all loaded samples. The distance between the calcified front and calcein labeling as a parameter representing the mineral apposition rate was significantly greater in the areas with strain intensity ≥100 με than in the area with strain intensity <100 με, suggesting that the bone formation activity of osteoblasts was locally enhanced by a higher mechanical strain. However, the shrunken osteocytes and the empty osteocyte lacunae were significantly lower in the highest strain area, suggesting that osteoclastogenesis was more retarded in higher strain areas than in lower strain areas. The histomorphometric parameters were not affected geometrically in the unloaded animals, suggesting that the load-induced mechanical strain caused differences in the histomorphometric parameters. Our findings support the hypothesis that bone cell activity related to bone resorption and formation is local strain-dependent on implant loading.

• Klíčová slova
• Bone remodeling, Dental implants, Histomorphometry, Mechanotransduction, Osteoblasts, Stress analysis,
• MeSH
• analýza metodou konečných prvků MeSH
• mechanický stres MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• osteocyty MeSH
• resorpce kosti * MeSH
• zubní implantáty * MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• zubní implantáty * MeSH

A silicalite-1 film (SF) deposited on Ti-6Al-4V alloy was investigated in this study as a promising coating for metallic implants. Two forms of SFs were prepared: as-synthesized SFs (SF-RT), and SFs heated up to 500 °C (SF-500) to remove the excess of template species from the SF surface. The SFs were characterized in detail by X-ray photoelectron spectroscopy (XPS), by Fourier transform infrared spectroscopy (FTIR), by scanning electron microscopy (SEM) and water contact angle measurements (WCA). Two types of bone-derived cells (hFOB 1.19 non-tumor fetal osteoblast cell line and U-2 OS osteosarcoma cell line) were used for a biocompatibility assessment. The initial adhesion of hFOB 1.19 cells, evaluated by cell numbers and cell spreading area, was better supported by SF-500 than by SF-RT. While no increase in cell membrane damage, in ROS generation and in TNF-alpha secretion of bone-derived cells grown on both SFs was found, gamma H2AX staining revealed an elevated DNA damage response of U-2 OS cells grown on heat-treated samples (SF-500). This study also discusses differences between osteosarcoma cell lines and non-tumor osteoblastic cells, stressing the importance of choosing the right cell type model.

• MeSH
• biokompatibilní materiály chemie   MeSH
• buněčná membrána účinky léků   MeSH
• buněčné linie MeSH
• cytotoxiny chemie   farmakologie   MeSH
• fotoelektronová spektroskopie metody   MeSH
• lidé MeSH
• mikroskopie elektronová rastrovací metody   MeSH
• nádorové buněčné linie MeSH
• osteoblasty účinky léků   MeSH
• osteocyty účinky léků   MeSH
• povrchové vlastnosti účinky léků   MeSH
• proliferace buněk účinky léků   MeSH
• slitiny MeSH
• testování materiálů metody   MeSH
• titan chemie   MeSH
• vysoká teplota MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• biokompatibilní materiály MeSH
• cytotoxiny MeSH
• slitiny MeSH
• titan MeSH
• titanium alloy (TiAl6V4) MeSH Prohlížeč

Mandibular/alveolar (m/a) bone, as a component of the periodontal apparatus, allows for the proper tooth anchorage and function of dentition. Bone formation around the tooth germs starts prenatally and, in the mouse model, the mesenchymal condensation turns into a complex vascularized bone (containing osteo-blasts, -cytes, -clasts) within only two days. This very short but critical period is characterized by synchronized cellular and molecular events. The m/a bone, as others, is subjected to endocrine regulations. This not only requires vasculature to allow the circulation of active molecules (ligands), but also the expression of corresponding cell receptors to define target tissues. This contribution aimed at following the dynamics of calciotropic receptors´ expression during morphological transformation of a mesenchymal condensation into the initial m/a bone structure. Receptors for all three calciotropic systemic regulators: parathormone, calcitonin and activated vitamin D (calcitriol), were localized on serial histological sections using immunochemistry and their relative expression was quantified by q-PCR. The onset of calciotropic receptors was followed along with bone cell differentiation (as checked using osteocalcin, sclerostin, RANK and TRAP) and vascularization (CD31) during mouse prenatal/embryonic (E) days 13-15 and 18. Additionally, the timing of calciotropic receptor appearance was compared with that of estrogen receptors (ESR1, ESR2). PTH receptor (PTH1r) appeared in the bone already at E13, when the first osteocalcin-positive cells were detected within the mesenchymal condensation forming the bone anlage. At this stage, blood vessels were only lining the condensation. At E14, the osteoblasts started to express the receptor for activated vitamin D (VDR). At this stage, the vasculature just penetrated the forming bone. On the same day, the first TRAP-positive (but not yet multinucleated) osteoclastic cells were identified. However, calcitonin receptor was detected only one day later. The first Sost-positive osteocytes, present at E15, were PTH1r and VDR positive. ESR1 almost copied the expression pattern of PTH1r, and ESR2 appearance was similar with VDR with a significant increase between E15 and E18. This report focuses on the in vivo situation and links morphological transformation of the mesenchymal cell condensation into a bone structure with dynamics of cell differentiation/maturation, vascularization and onset of receptors for calciotropic endocrine signalling in developing m/a bone.

• Klíčová slova
• Activated vitamin D, Calcitonin, Osteogenesis, Parathormone, Receptors,
• MeSH
• adaptorové proteiny signální transdukční analýza   genetika   MeSH
• buněčná diferenciace MeSH
• imunohistochemie MeSH
• kvantitativní polymerázová řetězová reakce MeSH
• mandibula růst a vývoj   MeSH
• messenger RNA analýza   MeSH
• myši MeSH
• osteoblasty fyziologie   MeSH
• osteocyty fyziologie   MeSH
• osteogeneze fyziologie   MeSH
• osteokalcin analýza   genetika   MeSH
• osteoklasty fyziologie   MeSH
• receptory kalcitoninu metabolismus   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• adaptorové proteiny signální transdukční MeSH
• messenger RNA MeSH
• osteokalcin MeSH
• receptory kalcitoninu MeSH
• Sost protein, mouse MeSH Prohlížeč

PURPOSE OF REVIEW: The goal of the review is to assess the appropriateness of menopausal hormone therapy (MHT) for the primary prevention of bone loss in women at elevated risk in the early years after menopause. RECENT FINDINGS: Estrogen alone or combined with progestin to protect the uterus from cancer significantly reduces the risk of osteoporosis-related fractures. MHT increases type 1 collagen production and osteoblast survival and maintains the equilibrium between bone resorption and bone formation by modulating osteoblast/osteocyte and T cell regulation of osteoclasts. Estrogens have positive effects on muscle and cartilage. Estrogen, but not antiresorptive therapies, can attenuate the inflammatory bone-microenvironment associated with estrogen deficiency. However, already on second year of administration, MHT is associated with excess breast cancer risk, increasing steadily with duration of use. MHT should be considered in women with premature estrogen deficiency and increased risk of bone loss and osteoporotic fractures. However, MHT use for the prevention of bone loss is hindered by increase in breast cancer risk even in women younger than 60 years old or who are within 10 years of menopause onset.

• Klíčová slova
• Bone cells, Estrogens, Fracture, Postmenopausal osteoporosis, Prevention,
• MeSH
• estrogenní substituční terapie metody   MeSH
• estrogeny terapeutické užití   MeSH
• hodnocení rizik MeSH
• kolagen typu I metabolismus   MeSH
• kosti a kostní tkáň metabolismus   MeSH
• lidé středního věku MeSH
• lidé MeSH
• nádory prsu epidemiologie   MeSH
• osteoblasty MeSH
• osteocyty MeSH
• osteogeneze MeSH
• osteoklasty MeSH
• osteoporotické fraktury prevence a kontrola   MeSH
• postmenopauzální osteoporóza metabolismus   prevence a kontrola   MeSH
• progestiny terapeutické užití   MeSH
• resorpce kosti MeSH
• T-lymfocyty MeSH
• výsledek terapie MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• estrogeny MeSH
• kolagen typu I MeSH
• progestiny MeSH

Sprouty proteins are modulators of the MAPK/ERK pathway. Amongst these, Sprouty2 (SPRY2) has been investigated as a possible factor that takes part in the initial phases of osteogenesis. However, the in vivo context has not yet been investigated and the underlying mechanisms taking place in vitro remain unknown. Therefore, in this study, the impact of Spry2 deficiency was examined in the developing tibias of Spry2 deficient (-/-) mouse. The investigation was performed when the osteogenic zone became clearly visible and when all three basic bone cells types were present. The main markers of osteoblasts, osteocytes and osteoclasts were evaluated by immunohistochemistry and RT-PCR. RT-PCR showed that the expression of Sost was 3.5 times higher in Spry2-/- than in the wild-type bone, which pointed to a still unknown mechanism of action of SPRY2 on the differentiation of osteocytes. The up-regulation of Sost was independent of Hif-1α expression and could not be related to its positive regulator, Runx2, since none of these factors showed an increased expression in the bone of Spry2-/- mice. Regarding the RANK/RANKL/OPG pathway, the Spry2-/- showed an increased expression of Rank, but no significant change in the expression of Rankl and Opg. Thanks to these results, the impact of Spry2 deletion is shown for the first time in the developing bone as a complex organ including, particularly, an effect on osteoblasts (Runx2) and osteocytes (Sost). This might explain the previously reported decrease in bone formation in postnatal Spry2-/- mice.

• Klíčová slova
• Endochondral bone development, SPROUTY2, growth plate, mouse, ossification,
• MeSH
• buněčná diferenciace MeSH
• cytoplazma metabolismus   MeSH
• faktor 1 indukovatelný hypoxií - podjednotka alfa metabolismus   MeSH
• ligand RANK metabolismus   MeSH
• membránové proteiny genetika   fyziologie   MeSH
• myši inbrední ICR MeSH
• myši knockoutované MeSH
• myši MeSH
• osteoblasty cytologie   metabolismus   MeSH
• osteocyty cytologie   metabolismus   MeSH
• osteogeneze * MeSH
• osteoklasty cytologie   metabolismus   MeSH
• osteoprotegerin metabolismus   MeSH
• proliferace buněk MeSH
• protein-serin-threoninkinasy genetika   fyziologie   MeSH
• vývoj kostí MeSH
• vývojová regulace genové exprese * MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• faktor 1 indukovatelný hypoxií - podjednotka alfa MeSH
• Hif1a protein, mouse MeSH Prohlížeč
• ligand RANK MeSH
• membránové proteiny MeSH
• osteoprotegerin MeSH
• protein-serin-threoninkinasy MeSH
• Spry2 protein, mouse MeSH Prohlížeč
• Tnfrsf11b protein, mouse MeSH Prohlížeč
• Tnfsf11 protein, mouse MeSH Prohlížeč

The skeleton shows an unconventional role in the physiology and pathophysiology of the human organism, not only as the target tissue for a number of systemic hormones, but also as endocrine tissue modulating some skeletal and extraskeletal systems. From this point of view, the principal cells in the skeleton are osteocytes. These cells primarily work as mechano-sensors and modulate bone remodeling. Mechanically unloaded osteocytes synthetize sclerostin, the strong inhibitor of bone formation and RANKL, the strong activator of bone resorption. Osteocytes also express hormonally active vitamin D (1,25(OH)(2)D) and phosphatonins, such as FGF23. Both 1,25(OH)(2)D and FGF23 have been identified as powerful regulators of the phosphate metabolism, including in chronic kidney disease. Further endocrine cells of the skeleton involved in bone remodeling are osteoblasts. While FGF23 targets the kidney and parathyroid glands to control metabolism of vitamin D and phosphates, osteoblasts express osteocalcin, which through GPRC6A receptors modulates beta cells of the pancreatic islets, muscle, adipose tissue, brain and testes. This article reviews some knowledge concerning the interaction between the bone hormonal network and phosphate or energy homeostasis and/or male reproduction.

• MeSH
• endokrinní systém fyziologie   MeSH
• fibroblastový růstový faktor 23 MeSH
• homeostáza fyziologie   MeSH
• lidé MeSH
• osteoblasty fyziologie   MeSH
• osteocyty fyziologie   MeSH
• remodelace kosti fyziologie   MeSH
• vitamin D metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• FGF23 protein, human MeSH Prohlížeč
• fibroblastový růstový faktor 23 MeSH
• vitamin D MeSH

Cortical bone plays a vital role in determining overall bone strength. We investigate the structural, compositional, and nanomechanical properties of cortical bone following ovariectomy (OVX) of 12-week-old Sprague Dawley rats, since this animal model is frequently employed to evaluate the performance of implantable biomaterials in compromised bone healing conditions. Morphological parameters and material properties of bone in the geometrical center of the femoral cortex were investigated four and eight weeks post-OVX and in unoperated controls (Ctrl), using X-ray micro-computed tomography, backscattered electron scanning electron microscopy, Raman spectroscopy, and nanoindentation. The OVX animals showed increase in body weight, diminished bone mineral density, increased intracortical porosity, but increased bone mass through periosteal apposition (e.g., increases in periosteal perimeter, cortical cross-sectional thickness, and cross-sectional area). However, osteocyte densities, osteocyte lacunar dimensions, and the nanomechanical behavior on the single mineralized collagen fibril level remained unaffected. Our correlative multiscale investigation provides structural, chemical, and nanomechanical evidence substantiating earlier reports suggesting that rats ovariectomized at 12 weeks undergo simultaneous bone loss and growth, resulting in the effects of OVX being less obvious. Periosteal apposition contradicts the conventional view of bone loss in osteoporosis but appears advantageous for the greater functional demand imposed on the skeleton by increased body weight and fragility induced by increased intracortical porosity. Through a variety of morphological changes, it is likely that 12-week-old rats are able to adapt to OVX-related microstructural and compositional alterations. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 997-1007, 2018.

• Klíčová slova
• Raman spectroscopy, bone, nanoindentation, osteoporosis, ovariectomy,
• MeSH
• biomechanika MeSH
• extracelulární matrix metabolismus   MeSH
• femur patologie   patofyziologie   MeSH
• kortikální kost diagnostické zobrazování   patologie   patofyziologie   MeSH
• lineární modely MeSH
• minerály metabolismus   MeSH
• nanočástice chemie   MeSH
• osteocyty metabolismus   MeSH
• osteoporóza diagnostické zobrazování   patologie   patofyziologie   MeSH
• počet buněk MeSH
• poréznost MeSH
• potkani Sprague-Dawley MeSH
• rentgenová mikrotomografie MeSH
• tělesná hmotnost MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• minerály MeSH