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2.
Z Gerontol Geriatr ; 53(2): 163-170, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31950363

RESUMO

Osteoporotic bones heal more slowly and ineffectively than normal bones. A combination of antibodies against sclerosing protein (Scl-Ab), and parathyroid hormone 1-34 (PTH 1-34) may improve healing. A standard osteoporotic rat model was established 12 weeks after bilateral ovarian resection (OVX). Bone defects were created in the right femora of 80 rats, which were randomly divided into 4 groups: control, Scl-Ab (25 mg/kg twice weekly), PTH (60 µg/kg of PTH 1-34 three times a week) and PTH plus Scl-Ab. After 12 weeks of treatment the rats were sacrificed and blood and the distal femora were harvested for biochemical evaluation, histology, microcomputed tomography and biomechanical testing. Compared to the control group, monotherapy and combination therapy with PTH and/or Scl-Ab promoted the formation of new bone, enhanced maximum femoral loading and increased the levels of procollagen type I N­terminal propeptide (PINP) and osteocalcin. The administration of PTH + Scl-Ab maximally enhanced bone defect healing. Combination treatment was better than either treatment alone, indicating a synergistic effect.


Assuntos
Anticorpos/administração & dosagem , Proteínas Morfogenéticas Ósseas/imunologia , Remodelação Óssea/fisiologia , Consolidação da Fratura/efeitos dos fármacos , Hormônio Paratireóideo/uso terapêutico , Animais , Densidade Óssea/efeitos dos fármacos , Calo Ósseo/efeitos dos fármacos , Modelos Animais de Doenças , Quimioterapia Combinada , Feminino , Humanos , Ovariectomia , Hormônio Paratireóideo/farmacologia , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Microtomografia por Raio-X/métodos
3.
Braz Oral Res ; 33: e086, 2019 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-31483052

RESUMO

Treatment of patients with bisphosphonate usage is a significant concern for oral surgeons because it interferes with jaw bone turnover and regeneration. In case of adverse effects manifesting related to bisphosphonate use, oral surgeons are usually treating and keep the patient's symptoms under control. In this study, we aimed to investigate a new treatment protocol for medication-related osteonecrosis of the jaw (MRONJ). This treatment protocol consisted of administering human parathyroid hormone (hPTH) loaded chitosan microspheres which were prepared by ionotropic gelation method or/and the prepared microspheres were suspended in a poloxamer gel. After in-vitro optimization studies, the efficacy of the chosen formulations was evaluated in-vivo studies. Zoledronic acid was administered daily to forty-eight adult female Sprague-Dawley rats, divided into four experimental groups, at a daily concentration of 0.11 mg/kg over three weeks to induce the MRONJ model. At the end of this period, maxillary left molar teeth were extracted. In the first group, the subjects received no treatment. In the negative control group, poloxamer hydrogel containing empty microspheres were immediately applied to the soft tissues surrounding the extraction socket. The treatment group-1 was treated with local injections of poloxamer hydrogel containing hPTH. The treatment group-2 was treated with a single local injection of poloxamer hydrogel containing hPTH-loaded chitosan microspheres. Both treatment groups received a total of 7 µg of hPTH at the end of the treatment protocol. Our study demonstrates successful attenuation of MRONJ through a local drug delivery system combined with hPTH, as opposed to previously attempted treatment strategies.


Assuntos
Conservadores da Densidade Óssea/farmacologia , Quitosana/farmacologia , Maxila/efeitos dos fármacos , Hormônio Paratireóideo/farmacologia , Animais , Osteonecrose da Arcada Osseodentária Associada a Difosfonatos/tratamento farmacológico , Osteonecrose da Arcada Osseodentária Associada a Difosfonatos/etiologia , Conservadores da Densidade Óssea/efeitos adversos , Conservadores da Densidade Óssea/uso terapêutico , Quitosana/uso terapêutico , Preparações de Ação Retardada , Feminino , Humanos , Maxila/patologia , Microesferas , Modelos Animais , Hormônio Paratireóideo/uso terapêutico , Poloxâmero/administração & dosagem , Poloxâmero/química , Ratos Sprague-Dawley , Ácido Zoledrônico/efeitos adversos
4.
PLoS One ; 14(7): e0219575, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31291372

RESUMO

Parathyroid hormone (PTH) is an anabolic bone drug approved by the US Food and Drug Administration (FDA) to treat osteoporosis. However, previous studies using cross-sectional designs have reported variable and sometimes contradictory results. The aim of the present study was to quantify the localized effect of PTH on the structural and densitometric behaviors of mouse tibia and their links with the global mechanical behavior of bone using a novel spatiotemporal image analysis approach and a finite element analysis technique. Twelve female C57BL/6J mice were divided into two groups: the control and PTH treated groups. The entire right tibiae were imaged using an in vivo micro-computed tomography (µCT) system eight consecutive times. Next, the in vivo longitudinal tibial µCT images were rigidly registered and divided into 10 compartments across the entire tibial space. The bone volume (BV), bone mineral content (BMC), bone tissue mineral density (TMD), and tibial endosteal and periosteal areas (TEA and TPA) were quantified in each compartment. Additionally, finite element models of all the tibiae were generated to analyze the failure behavior of the tibia. It was found that both the BMC and BV started to increase in the proximal tibial region, and then the increases extended to the entire tibial region after two weeks of treatment (p < 0.05). PTH intervention significantly reduced the TEA in most tibial compartments after two weeks of treatment, and the TPA increased in most tibial regions after four weeks of treatment (p < 0.05). Tibial failure loads significantly increased after three weeks of PTH treatment (p < 0.01). The present study provided the first evidence of the localized effect of PTH on bone structural and densitometric properties, as well as their links with the global mechanical behaviors of bone, which are important pieces of information for unveiling the mechanism of PTH intervention.


Assuntos
Densidade Óssea/efeitos dos fármacos , Osteoporose/tratamento farmacológico , Fraturas por Osteoporose/prevenção & controle , Hormônio Paratireóideo/farmacologia , Tíbia/efeitos dos fármacos , Animais , Densitometria/métodos , Modelos Animais de Doenças , Feminino , Análise de Elementos Finitos , Camundongos , Camundongos Endogâmicos C57BL , Osteoporose/complicações , Fraturas por Osteoporose/etiologia , Hormônio Paratireóideo/uso terapêutico , Análise Espaço-Temporal , Tíbia/diagnóstico por imagem , Tíbia/fisiologia , Suporte de Carga , Microtomografia por Raio-X
5.
Am J Orthod Dentofacial Orthop ; 155(5): 670-680, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31053283

RESUMO

INTRODUCTION: This study investigated the effects of different doses of parathyroid hormone (PTH) on orthodontic tooth movement after mandibular ramus osteotomy and the associated dose-response relationship. METHODS: One-hundred twenty rabbits were divided into 2 experimental groups (A and B) and 2 control groups (control group and negative control group). An experimental model of mandibular ramus osteotomy with installation of an orthodontic tooth movement device was established in groups A and B and the control group. After surgery, groups A and B received intermittent subcutaneous injections of PTH, 20 and 40 µg/kg, respectively, and the control group received injections of normal saline solution. The negative control group underwent installation of the orthodontic tooth movement device without mandibular ramus osteotomy and received normal saline solution after surgery. Changes in expression of RANKL and RUNX2 in the periodontal tissues of the first molars were evaluated by means of immunohistochemical analysis and quantitative fluorescence polymerase chain reaction. RESULTS: Movement of the first molars was more rapid in group B than in group A in the 21 days after surgery. Significantly higher RANKL mRNA levels and lower RUNX2 mRNA levels were detected on the compression side of the periodontal tissues in groups A and B than in the control groups. There was a significant difference in RANKL and RUNX2 expression levels between group B and the control groups at all time points. CONCLUSIONS: Mandibular ramus osteotomy combined with high-dose PTH can increase catabolism on the compressed periodontal tissues, thereby accelerating remodeling of periodontal bone and promoting orthodontic tooth movement after surgery.


Assuntos
Osteotomia Mandibular , Hormônio Paratireóideo/farmacologia , Técnicas de Movimentação Dentária , Animais , Remodelação Óssea/fisiologia , Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Relação Dose-Resposta a Droga , Humanos , Imuno-Histoquímica , Hormônio Paratireóideo/administração & dosagem , Reação em Cadeia da Polimerase , Ligante RANK/metabolismo , Coelhos
6.
Science ; 364(6436): 148-153, 2019 04 12.
Artigo em Inglês | MEDLINE | ID: mdl-30975883

RESUMO

The parathyroid hormone receptor-1 (PTH1R) is a class B G protein-coupled receptor central to calcium homeostasis and a therapeutic target for osteoporosis and hypoparathyroidism. Here we report the cryo-electron microscopy structure of human PTH1R bound to a long-acting PTH analog and the stimulatory G protein. The bound peptide adopts an extended helix with its amino terminus inserted deeply into the receptor transmembrane domain (TMD), which leads to partial unwinding of the carboxyl terminus of transmembrane helix 6 and induces a sharp kink at the middle of this helix to allow the receptor to couple with G protein. In contrast to a single TMD structure state, the extracellular domain adopts multiple conformations. These results provide insights into the structural basis and dynamics of PTH binding and receptor activation.


Assuntos
Hormônio Paratireóideo/química , Receptor Tipo 1 de Hormônio Paratireóideo/agonistas , Receptor Tipo 1 de Hormônio Paratireóideo/química , Motivos de Aminoácidos , Microscopia Crioeletrônica , Humanos , Hormônio Paratireóideo/farmacologia , Hormônio Paratireóideo/fisiologia , Ligação Proteica , Domínios Proteicos , Receptor Tipo 1 de Hormônio Paratireóideo/ultraestrutura
7.
Clin Exp Nephrol ; 23(7): 898-907, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30895530

RESUMO

BACKGROUND: Injection of parathyroid hormone (PTH) rapidly stimulates renal Pi excretion, in part by downregulating NaPi-IIa (Npt2a/SLC34A1) and NaPi-IIc (Npt2c/SLC34A3) transporters. The mechanisms underlying the effects of PTH on NaPi-IIc are not fully elucidated. METHODS: We analyzed the effect of PTH on inorganic phosphate (Pi) reabsorption in Npt2a-/- mice to eliminate the influence of Npt2a on renal Pi reabsorption. In opossum kidney (OK) cells and Xenopus oocytes, we investigated the effect of NaPi-IIc transporter phosphorylation. Studies of mice with mutations of NaPi-IIc protein in which serine and threonine were replaced with either alanine (A), which prevents phosphorylation, or aspartic acid (D), which mimics the charged state of phosphorylated NaPi-IIc, were also performed to evaluate the involvement of phosphorylation in the regulation of transport function. RESULTS: The Npt2a-/- experiments showed that PTH administration rapidly inactivated NaPi-IIc function in the apical membrane of proximal tubular cells. Analysis of mutant proteins (S71, S138, T151, S174, T583) at putative protein kinase C sites, revealed that S138 markedly suppressed the function and cellular expression of mouse NaPi-IIc in Xenopus oocytes and OK cells. In addition, 138D had a short half-life compared with wild-type protein. CONCLUSIONS: The present study suggests that acute regulation of NaPi-IIc protein by PTH is involved in the inactivation of Na+-dependent Pi cotransporter activity and that phosphorylation of the transporter is involved in the rapid modification.


Assuntos
Túbulos Renais Proximais/efeitos dos fármacos , Hormônio Paratireóideo/farmacologia , Fragmentos de Peptídeos/farmacologia , Fosfatos/metabolismo , Proteína Quinase C/metabolismo , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Reabsorção Renal/efeitos dos fármacos , Proteínas Cotransportadoras de Sódio-Fosfato Tipo IIc/metabolismo , Animais , Linhagem Celular , Feminino , Túbulos Renais Proximais/metabolismo , Masculino , Camundongos Knockout , Gambás , Fosforilação , Estabilidade Proteica , Proteínas Cotransportadoras de Sódio-Fosfato Tipo IIa/deficiência , Proteínas Cotransportadoras de Sódio-Fosfato Tipo IIa/genética , Proteínas Cotransportadoras de Sódio-Fosfato Tipo IIc/genética , Fatores de Tempo , Xenopus
8.
Nat Commun ; 10(1): 1354, 2019 03 22.
Artigo em Inglês | MEDLINE | ID: mdl-30902975

RESUMO

Osteoporosis is caused by increased bone resorption and decreased bone formation. Intermittent administration of a fragment of Parathyroid hormone (PTH) activates osteoblast-mediated bone formation and is used in patients with severe osteoporosis. However, the mechanisms by which PTH elicits its anabolic effect are not fully elucidated. Here we show that the absence of the homeodomain protein TG-interacting factor 1 (Tgif1) impairs osteoblast differentiation and activity, leading to a reduced bone formation. Deletion of Tgif1 in osteoblasts and osteocytes decreases bone resorption due to an increased secretion of Semaphorin 3E (Sema3E), an osteoclast-inhibiting factor. Tgif1 is a PTH target gene and PTH treatment failed to increase bone formation and bone mass in Tgif1-deficient mice. Thus, our study identifies Tgif1 as a novel regulator of bone remodeling and an essential component of the PTH anabolic action. These insights contribute to a better understanding of bone metabolism and the anabolic function of PTH.


Assuntos
Anabolizantes/farmacologia , Remodelação Óssea/efeitos dos fármacos , Hormônio Paratireóideo/farmacologia , Proteínas Repressoras/deficiência , Animais , Osso e Ossos/efeitos dos fármacos , Osso e Ossos/metabolismo , Diferenciação Celular/efeitos dos fármacos , Deleção de Genes , Glicoproteínas/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular , Camundongos Endogâmicos C57BL , Tamanho do Órgão/efeitos dos fármacos , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacos , Osteoblastos/metabolismo , Osteoclastos/citologia , Osteoclastos/efeitos dos fármacos , Osteoclastos/metabolismo , Proteínas Repressoras/metabolismo , Semaforinas/farmacologia , Fator de Transcrição AP-1/metabolismo , Via de Sinalização Wnt/efeitos dos fármacos
9.
Endocrinology ; 160(5): 1348-1358, 2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-30916761

RESUMO

Fibroblast growth factor 23 (FGF23) secretion is facilitated by the PTH, particularly in hyperparathyroidism. The PTH also attenuates dentin matrix protein 1 (DMP1), which is produced by osteocytes to contribute to bone mineralization and suppress FGF23 expression. Nevertheless, it remains unknown whether attenuated DMP1 affects FGF23 expression in hyperparathyroidism. We examined their expression in bone tissue using a mouse model of primary hyperparathyroidism (PHPT). PHPT mice increased serum FGF23 levels, along with a high level of serum PTH. Fgf23 expression increased, and Dmp1 decreased significantly in the calvaria of PHPT mice compared with wild-type mice and primary osteoblasts treated with PTH. In UMR106 mature osteoblasts, PTH increased Fgf23 expression and decreased Dmp1 expression, and stimulation of protein kinase A (PKA) signaling by forskolin also increased Fgf23 expression and decreased Dmp1 expression in a dose-dependent manner, whereas inhibition of PKA signaling with 10-5 M H89 reversed the changes in Fgf23 and Dmp1 expression when cells were stimulated with PTH. Silencing Dmp1 along with PTH treatment led to an additive increase in Fgf23 expression, accompanied by additive phosphorylation of the cAMP-response element-binding protein. These results indicate that persistent and high levels of PTH lead to the continuous activation of PKA signaling in osteoblasts/osteocytes, resulting in an increase in FGF23 and a decrease in DMP1 in bone. Moreover, suppression of DMP1 enhanced FGF23 expression in PHPT, besides having a direct effect on PTH. These mechanisms may describe one of the pathogeneses behind the increase in FGF23 transcription in bone tissue in patients with PHPT.


Assuntos
Modelos Animais de Doenças , Proteínas da Matriz Extracelular/metabolismo , Fatores de Crescimento de Fibroblastos/metabolismo , Hiperparatireoidismo Primário/metabolismo , Crânio/metabolismo , Animais , Linhagem Celular Tumoral , Células Cultivadas , Proteínas da Matriz Extracelular/genética , Fatores de Crescimento de Fibroblastos/sangue , Fatores de Crescimento de Fibroblastos/genética , Expressão Gênica/efeitos dos fármacos , Humanos , Hiperparatireoidismo Primário/genética , Camundongos Endogâmicos C57BL , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacos , Osteoblastos/metabolismo , Hormônio Paratireóideo/sangue , Hormônio Paratireóideo/farmacologia , Interferência de RNA , Ratos
10.
Arch Oral Biol ; 99: 161-168, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30710837

RESUMO

OBJECTIVES: The aim of this study was to investigate the effects of continuous parathyroid hormone (cPTH) and intermittent parathyroid hormone (iPTH) on bone formation and bone resorption in midpalatal suture during maxillary expansion. METHODS: Forty-eight male SD rats were randomly divided into four groups (n = 12 each), including the control, the expansion (E), the E + cPTH, and the E + iPTH. A thermosensitive controlled-release hydrogel was synthesized for cPTH administration. All animals were sacrificed after seven days. Microcomputed tomography, histochemical staining and real-time PCR were used to investigate the bone remodeling of midpalatal suture. Serum chemistry was adopted to evaluate the systemic condition of experimental animals. RESULTS: The suture width was increased by the expansion, and further elevated by cPTH and iPTH administration. Both regimes improved bone volume fraction and trabecular thickness of suture bone region. Moreover, both cPTH and iPTH decreased SOST expression and enhanced the expression of ß-catenin and Col-I. cPTH increased RANKL expression, inhibited OPG expression, and resulted in an increment of osteoclasts, while iPTH had no influence on osteoclastogenesis. The serum calcium concentration was enhanced by PTH administration. CONCLUSION: Both cPTH and iPTH promote midpalatal suture expansion by enhancing bone formation, probably via SOST downregulation and the resulting ß-catenin activation. Our results demonstrated that PTH administration may have potential to be an adjunctive approach for maxillary expansion treatment.


Assuntos
Suturas Cranianas/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Técnica de Expansão Palatina , Hormônio Paratireóideo/administração & dosagem , Hormônio Paratireóideo/farmacologia , Animais , Remodelação Óssea/efeitos dos fármacos , Reabsorção Óssea/metabolismo , Reabsorção Óssea/patologia , Suturas Cranianas/diagnóstico por imagem , Suturas Cranianas/patologia , Masculino , Modelos Animais , Aparelhos Ortodônticos , Osteoclastos/efeitos dos fármacos , Técnica de Expansão Palatina/instrumentação , Ligante RANK/metabolismo , Ratos , Fatores de Tempo , Microtomografia por Raio-X , beta Catenina/metabolismo
11.
J Mater Sci Mater Med ; 30(2): 25, 2019 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-30747334

RESUMO

Pharmacological therapy of osteoporosis reduces bone loss and risk of fracture in patients. Modulation of bone mineral density cannot explain all effects. Other aspects of bone quality affecting fragility and ways to monitor them need to be better understood. Keratinous tissue acts as surrogate marker for bone protein deterioration caused by oestrogen deficiency in rats. Ovariectomised rats were treated with alendronate (ALN), parathyroid hormone (PTH) or estrogen (E2). MicroCT assessed macro structural changes. Raman spectroscopy assessed biochemical changes. Micro CT confirmed that all treatments prevented ovariectomy-induced macro structural bone loss in rats. PTH induced macro structural changes unrelated to ovariectomy. Raman analysis revealed ALN and PTH partially protect against molecular level changes to bone collagen (80% protection) and mineral (50% protection) phases. E2 failed to prevent biochemical change. The treatments induced alterations unassociated with the ovariectomy; increased beta sheet with E2, globular alpha helices with PTH and fibrous alpha helices with both ALN and PTH. ALN is closest to maintaining physiological status of the animals, while PTH (comparable protective effect) induces side effects. E2 is unable to prevent molecular level changes associated with ovariectomy. Raman spectroscopy can act as predictive tool for monitoring pharmacological therapy of osteoporosis in rodents. Keratinous tissue is a useful surrogate marker for the protein related impact of these therapies.The results demonstrate utility of surrogates where a clear systemic causation connects the surrogate to the target tissue. It demonstrates the need to assess broader biomolecular impact of interventions to examine side effects.


Assuntos
Osteoporose Pós-Menopausa/diagnóstico , Osteoporose Pós-Menopausa/terapia , Análise Espectral Raman , Alendronato/farmacologia , Animais , Peso Corporal , Densidade Óssea , Conservadores da Densidade Óssea/farmacologia , Modelos Animais de Doenças , Estrogênios/metabolismo , Feminino , Humanos , Queratinas/química , Hormônio Paratireóideo/farmacologia , Ratos , Ratos Sprague-Dawley , Microtomografia por Raio-X
12.
Am J Physiol Renal Physiol ; 316(5): F934-F947, 2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-30785349

RESUMO

The objective of the present study was to theoretically investigate the mechanisms underlying uric acid transport in the proximal tubule (PT) of rat kidneys, and their modulation by factors, including Na+, parathyroid hormone, ANG II, and Na+-glucose cotransporter-2 inhibitors. To that end, we incorporated the transport of uric acid and its conjugate anion urate in our mathematical model of water and solute transport in the rat PT. The model accounts for parallel urate reabsorption and secretion pathways on apical and basolateral membranes and their coupling to lactate and α-ketoglutarate transport. Model results agree with experimental findings at the segment level. Net reabsorption of urate by the rat PT is predicted to be ~70% of the filtered load, with a rate of urate removal from the lumen that is 50% higher than the rate of urate secretion. The model suggests that apical URAT1 deletion significantly reduces net urate reabsorption across the PT, whereas ATP-binding cassette subfamily G member 2 dysfunction affects it only slightly. Inactivation of basolateral glucose transporter-9 raises fractional urate excretion above 100%, as observed in patients with renal familial hypouricemia. Furthermore, our results suggest that reducing Na+ reabsorption across Na+/H+ exchangers or Na+-glucose cotransporters augments net urate reabsorption. The model predicts that parathyroid hormone reduces urate excretion, whereas ANG II increases it. In conclusion, we have developed the first model of uric acid transport in the rat PT; this model provides a framework to gain greater insight into the numerous solutes and coupling mechanisms that affect the renal handing of uric acid.


Assuntos
Túbulos Renais Proximais/metabolismo , Modelos Biológicos , Reabsorção Renal , Ácido Úrico/metabolismo , Membro 2 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/metabolismo , Angiotensina II/farmacologia , Animais , Proteínas de Transporte de Ânions/metabolismo , Transporte Biológico , Túbulos Renais Proximais/efeitos dos fármacos , Proteínas de Transporte de Monossacarídeos/metabolismo , Hormônio Paratireóideo/farmacologia , Ratos , Reabsorção Renal/efeitos dos fármacos , Via Secretória , Sódio/metabolismo
13.
Am J Physiol Endocrinol Metab ; 316(4): E590-E604, 2019 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-30668150

RESUMO

Parathyroid hormone (PTH) and its related peptide (PTH-related peptide 1-34) are two of the Food and Drug Administration-approved bone-promoting drugs for age-related osteoporosis. Treatment with PTH stimulates bone formation. However, the molecular mechanisms of PTH-mediated osteoblast differentiation and cell proliferation are still not completely understood. In this study, we showed that PTH induced endoplasmic reticulum (ER) stress in osteoblasts through the PKR-like endoplasmic reticulum kinase (PERK)-eukaryotic initiation factor 2α (EIF2α)-activating transcription factor 4 (ATF4)-signaling pathway. After separately blocking PERK-EIF2α-ATF4 signaling with two different inhibitors [AMG'44 and integrated stress response inhibitor (ISRIB)] or specific small interfering RNA for PERK and ATF4, the following targets were all downregulated: expression of osteoblast differentiation markers [runt-related transcription factor 2 (Runx2), alkaline phosphatase (Alp), type I collagen (Col1a1), and osteocalcin (Ocn)], cell proliferation markers (CyclinE, CyclinD, and CDC2), amino acid import (Glyt1), and metabolism-related genes (Asns). Additionally, Alp-positive staining cells, Alp activity, matrix mineralization, Ocn secretion, and cell proliferation indexes were inhibited. Interestingly, we found that salubrinal enhanced PTH-induced osteoblast differentiation and proliferation by maintenance of phosphorylation of EIF2α. Furthermore, we observed that PTH increased the association between heat shock protein 90 (HSP90) and PERK and maintained PERK protein stabilization in the early stages of PTH-induced ER stress. Treatment of MC3T3-E1 cells with geldanamycin, an HSP90 inhibitor, decreased PERK protein expression and inhibited osteoblast differentiation and cell proliferation upon PTH treatment. Taken together, our data demonstrate that PTH regulates osteoblast differentiation and cell proliferation, partly by activating the HSP90-dependent PERK-EIF2α-ATF4 signaling pathway.


Assuntos
Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Osteoblastos/efeitos dos fármacos , Hormônio Paratireóideo/farmacologia , Fator 4 Ativador da Transcrição/metabolismo , Fosfatase Alcalina/efeitos dos fármacos , Fosfatase Alcalina/metabolismo , Animais , Benzoquinonas/farmacologia , Proteína Quinase CDC2/efeitos dos fármacos , Proteína Quinase CDC2/metabolismo , Linhagem Celular , Colágeno Tipo I/efeitos dos fármacos , Colágeno Tipo I/metabolismo , Subunidade alfa 1 de Fator de Ligação ao Core/efeitos dos fármacos , Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Ciclina D/efeitos dos fármacos , Ciclina D/metabolismo , Ciclina E/efeitos dos fármacos , Ciclina E/metabolismo , Inibidores Enzimáticos/farmacologia , Fator de Iniciação 2 em Eucariotos/metabolismo , Proteínas da Membrana Plasmática de Transporte de Glicina/efeitos dos fármacos , Proteínas da Membrana Plasmática de Transporte de Glicina/metabolismo , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Proteínas de Choque Térmico HSP90/efeitos dos fármacos , Proteínas de Choque Térmico HSP90/metabolismo , Lactamas Macrocíclicas/farmacologia , Camundongos , Osteoblastos/metabolismo , Osteocalcina/efeitos dos fármacos , Osteocalcina/metabolismo , Transdução de Sinais , eIF-2 Quinase/metabolismo
14.
Hum Genet ; 138(2): 151-166, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30661131

RESUMO

Previous genome-wide linkage and association studies have identified an osteoporosis-associated locus at 1p36 that harbors SNPs rs34920465 and rs6426749. The 1p36 locus also comprises the WNT4 gene with known role in bone metabolism and functionally unknown ZBTB40/lncRNA ZBTB40-IT1 genes. How these might interact to contribute to osteoporosis susceptibility is not known. In this study, we show that lncRNA ZBTB40-IT1 is able to suppress osteogenesis and promote osteoclastogenesis by regulating the expression of WNT4, RUNX2, OSX, ALP, COL1A1, OPG and RANKL in U-2OS and hFOB1.19 cell lines, whereas ZBTB40 plays an opposite role in bone metabolism. Treatment with parathyroid hormone significantly downregulates the expression of ZBTB40-IT1 in U-2OS cell lines. ZBTB40 can suppress ZBTB40-IT1 expression but has no response to parathyroid hormone treatment. Dual-luciferase assay and biotin pull-down assay demonstrate that osteoporosis GWAS lead SNPs rs34920465-G and rs6426749-C alleles can respectively bind transcription factors JUN::FOS and CREB1, and upregulate ZBTB40 and ZBTB40-IT1 expression. Our study discovers the critical role of ZBTB40 and lncRNA ZBTB40-IT1 in bone metabolism, and provides a mechanistic basis for osteoporosis GWAS lead SNPs rs34920465 and rs6426749.


Assuntos
Regulação da Expressão Gênica , Predisposição Genética para Doença , Osteogênese/genética , Osteoporose , Polimorfismo de Nucleotídeo Único , RNA Longo não Codificante , Alelos , Linhagem Celular Tumoral , Proteínas de Ligação a DNA/biossíntese , Proteínas de Ligação a DNA/genética , Estudo de Associação Genômica Ampla , Células HEK293 , Humanos , Osteoporose/genética , Osteoporose/metabolismo , Osteoporose/patologia , Hormônio Paratireóideo/metabolismo , Hormônio Paratireóideo/farmacologia , RNA Longo não Codificante/biossíntese , RNA Longo não Codificante/genética
15.
Chem Biol Interact ; 300: 101-110, 2019 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-30639440

RESUMO

Osteoporosis is accompanied by insufficient osteogenic capacity. Several lines of evidence suggested that solutions to enhance osteoblastogenesis were important strategies for osteoporotic bone defect repair. This study investigated the effect of combined treatment with vitamin K2 and PTH on bone formation in calvarial bone defect in osteoporotic rats and its influence on osteoblast in vitro. Bilateral ovariectomy was used in SPF Sprague Dawley rats to generate an osteoporosis model. Subsequently, a calvarial defect model was established and all osteoporotic rats were randomly assigned to the following groups: control, VK (vitamin K2, 30 mg/kg everyday), PTH (recombinant human PTH (1-34), 60 µg/kg, three times a week) or VK + PTH (vitamin K2, 30 mg/kg everyday plus PTH, 60 µg/kg three times a week) for 8 weeks. In vitro, bone marrow-derived stem cells (BMSCs) were cultured and treated with vitamin K2, PTH or vitamin K2+PTH. ALP staining and western blot were performed to observe the influence of combined treatment on BMSCs. Bone formation within calvarial defect were assessed by serum γ-carboxylated osteocalcin (Gla-OC), micro-CT, histological and immunofluorescent labeling. In this study, combined treatment of PTH and vitamin K2 showed positive effects on preventing bone loss in femurs in OVX rats. Combined treatment increased serum Gla-OC and promoted bone formation in osteoporotic calvarial bone defects. Immunohistochemistry showed that OCN and RUNX2 were more highly expressed in the VK + PTH group than in the control groups. In vitro studies results suggested that combined treatment with PTH and vitamin K2 increased expression of ALP, BMP2 and RUNX2 in BMSCs. Our data suggested that the combination of vitamin K2 and PTH increased differentiation of osteoblast and had a synergistic effect on bone formation in osteoporotic calvarial bone defect.


Assuntos
Diferenciação Celular/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Hormônio Paratireóideo/farmacologia , Vitamina K 2/farmacologia , Animais , Biomarcadores/sangue , Células da Medula Óssea/citologia , Colágeno Tipo I/sangue , Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Feminino , Fêmur/diagnóstico por imagem , Fêmur/metabolismo , Fêmur/patologia , Humanos , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacos , Osteoblastos/metabolismo , Osteocalcina/metabolismo , Ovariectomia , Hormônio Paratireóideo/genética , Hormônio Paratireóideo/metabolismo , Fragmentos de Peptídeos/sangue , Ratos , Ratos Sprague-Dawley , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/farmacologia , Células-Tronco/citologia , Células-Tronco/efeitos dos fármacos , Células-Tronco/metabolismo , Microtomografia por Raio-X
16.
FASEB J ; 33(2): 2885-2898, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30354669

RESUMO

Intermittent administration of parathyroid hormone (PTH) stimulates bone formation in vivo and also suppresses the volume of bone marrow adipose tissue (BMAT). In contrast, a calorie-restricted (CR) diet causes bone loss and induces BMAT in both mice and humans. We used the CR model to test whether PTH would reduce BMAT in mice by both altering cell fate and inducing lipolysis of marrow adipocytes. Eight-week-old mice were placed on a control (Ctrl) diet or CR diet. At 12 wk, CR and Ctrl mice were injected daily with PTH (CR/PTH or Ctrl/PTH) or vehicle for 4 wk. Two other cohorts were CR and simultaneously injected (CR + PTH or CR + Veh) for 4 wk. CR mice had low bone mass and increased BMAT in the proximal tibias. PTH significantly increased bone mass in all cohorts despite calorie restrictions. Adipocyte density and size were markedly increased with restriction of calories. PTH reduced adipocyte numbers in CR + PTH mice, whereas adipocyte size was reduced in CR/PTH-treated mice. In contrast, osteoblast number was increased 3-8-fold with PTH treatment. In vitro, bone marrow stromal cells differentiated into adipocytes and, treated with PTH, exhibited increased production of glycerol and fatty acids. Moreover, in cocultures of bone marrow adipocyte and osteoblast progenitors, PTH stimulated the transfer of fatty acids to osteoblasts. In summary, PTH administration to CR mice increased bone mass by shifting lineage allocation toward osteogenesis and inducing lipolysis of mature marrow adipocytes. The effects of PTH on bone marrow adiposity could enhance its anabolic actions by providing both more cells and more fuel for osteoblasts during bone formation.-Maridas, D. E., Rendina-Ruedy, E., Helderman, R. C., DeMambro, V. E., Brooks, D., Guntur, A. R., Lanske, B., Bouxsein, M. L., Rosen, C. J. Progenitor recruitment and adipogenic lipolysis contribute to the anabolic actions of parathyroid hormone on the skeleton.


Assuntos
Adipócitos/citologia , Reabsorção Óssea/tratamento farmacológico , Lipólise/efeitos dos fármacos , Células-Tronco Mesenquimais/citologia , Osteoblastos/citologia , Hormônio Paratireóideo/farmacologia , Células-Tronco/citologia , Adipócitos/efeitos dos fármacos , Adipócitos/metabolismo , Adipogenia , Animais , Reabsorção Óssea/metabolismo , Reabsorção Óssea/patologia , Restrição Calórica , Diferenciação Celular , Células Cultivadas , Feminino , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Osteoblastos/efeitos dos fármacos , Osteoblastos/metabolismo , Osteogênese , Células-Tronco/efeitos dos fármacos , Células-Tronco/metabolismo
17.
In Vitro Cell Dev Biol Anim ; 55(1): 45-51, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30397855

RESUMO

Osteocytes regulate bone remodeling, especially in response to mechanical loading and unloading of bone, with nitric oxide reported to play an important role in that process. In the present study, we found that 8-nitroguanosine 3',5'-cyclic monophosphate (8-nitro-cGMP), a second messenger of nitric oxide in various types of cells, was produced by osteocytes in bone tissue as well as cultured osteocytic Ocy454 cells. The amount of 8-nitro-cGMP in Ocy454 cells increased during incubation with parathyroid hormone or prostaglandin E2, both of which are known to upregulate receptor activator of nuclear factor-κB ligand (RANKL) mRNA expression in osteocytes. On the other hand, exogenous 8-nitro-cGMP did not have effects on either the presence or absence of these bioactive substances. Furthermore, neither an inhibitor of nitric oxide synthase nor 8-bromo-cGMP, a cell-permeable analog of cGMP, showed remarkable effects on mRNA expression of sclerostin or RANKL. These results indicate that neither nitric oxide nor its downstream compounds, including 8-nitro-cGMP, alone are sufficient for induction of functional changes in osteocytes.


Assuntos
GMP Cíclico/análogos & derivados , Dinoprostona/farmacologia , Osteócitos/metabolismo , Hormônio Paratireóideo/farmacologia , Regulação para Cima , Animais , Linhagem Celular , GMP Cíclico/biossíntese , Proteínas da Matriz Extracelular/genética , Proteínas da Matriz Extracelular/metabolismo , Fêmur/citologia , Glicoproteínas/genética , Glicoproteínas/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular , Masculino , Camundongos Endogâmicos C57BL , Osteoprotegerina/genética , Osteoprotegerina/metabolismo , Ligante RANK/genética , Ligante RANK/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Fator de Necrose Tumoral alfa/farmacologia
18.
EBioMedicine ; 40: 56-66, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30528454

RESUMO

BACKGROUND: Parathyroid hormone related protein (PTHrP) triggers white adipose tissue (WAT) browning and cachexia in lung cancer mouse models. It remains unknown whether excessive PTH secretion affects WAT browning and to what extent it contributes to body weight change in primary hyperparathyroidism (PHPT). METHODS: Using the adeno-associated virus injection, Pth gene over-expressed mice mimicking PHPT were firstly established to observe their WAT browning and body weight alteration. The association between PTH and body weight was investigated in 496 PHPT patients. The adipose browning activities of 20 PHPT and 60 control subjects were measured with PET/CT scanning. FINDINGS: Elevated plasma PTH triggered adipose tissue browning, leading to increased energy expenditure, reduced fat content, and finally decreased body weight in PHPT mice. Higher circulating PTH levels were associated with lower body weight (ß = -0.048, P = .0003) independent of renal function, serum calcium, phosphorus,and albumin levels in PHPT patients. PHPT patients exhibited both higher prevalence of detectable brown/beige adipose tissue (20% vs 3.3%, P = .03) and increased browning activities (SUV in cervical adipose was 0.77 vs 0.49,P = .02) compared with control subjects. INTERPRETATION: Elevated serum PTH drove WAT browning program, which contributed in part to body weight loss in both PHPT mice and patients. These results give insights into the novel pathological effect of PTH and are of importance in understanding the metabolic changes of PHPT. FUND: This research is supported by the National Key Research and Development Program of China and National Natural Science Foundation of China.


Assuntos
Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Branco/metabolismo , Hiperparatireoidismo Primário/metabolismo , Perda de Peso , Tecido Adiposo Marrom/efeitos dos fármacos , Tecido Adiposo Branco/efeitos dos fármacos , Animais , Dependovirus/genética , Feminino , Expressão Gênica , Vetores Genéticos/genética , Humanos , Hiperparatireoidismo Primário/diagnóstico , Hiperparatireoidismo Primário/fisiopatologia , Masculino , Camundongos , Pessoa de Meia-Idade , Consumo de Oxigênio , Hormônio Paratireóideo/genética , Hormônio Paratireóideo/metabolismo , Hormônio Paratireóideo/farmacologia , Tomografia Computadorizada com Tomografia por Emissão de Pósitrons , Ratos
19.
Bone ; 120: 548-555, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30465918

RESUMO

Chronic PTH deficiency has a marked effect on the skeleton, leading to characteristic decreases in bone remodeling and increases in bone mass. An effect on fracture risk has not been demonstrated, although biochemical, imaging, and histomorphometric data indicate abnormalities in skeletal properties1,21,21,21,2. Replacement with PTH leads to a new skeletal state that is maintained with long-term treatment.


Assuntos
Osso e Ossos/patologia , Hipoparatireoidismo/patologia , Densidade Óssea/efeitos dos fármacos , Osso e Ossos/diagnóstico por imagem , Fraturas Ósseas/etiologia , Humanos , Hipoparatireoidismo/diagnóstico por imagem , Hipoparatireoidismo/tratamento farmacológico , Hormônio Paratireóideo/farmacologia , Hormônio Paratireóideo/uso terapêutico , Fatores de Risco
20.
Z Gerontol Geriatr ; 52(2): 139-147, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29476205

RESUMO

Recently, the use of the pharmacological agents strontium ranelate (SR), parathyroid hormone (1-34, PTH) and zoledronic acid (ZA) has come to prominence for the treatment of osteoporosis due to their ability to prevent bone loss in osteoporotic patients. Although much emphasis has been placed on using pharmacological agents for the prevention of disease, much less attention has been placed on which one is more effective. There is still no direct comparative study on these three drugs. The aim of the present study was to investigate the effect of SR, PTH, ZA on preventing ovariectomy-induced osteoporosis in rats. After bilateral ovariectomy the rats randomly received vehicle, SR (500 mg/kg body weight/day, orally), PTH (20 µg/kg/day, subcutaneously) or a single injection of ZA (0.1 mg/kg, i.v.) until death at 12 weeks. The distal femurs were harvested for evaluation of bone metabolism. The rats treated with ZA demonstrated the highest levels of new bone formation as assessed by microcomputed tomography (CT), biomechanical strength, histological analysis and bone metabolism. Furthermore, PTH and SR showed a stronger effect on improving trabecular bone mass at 12 weeks. The results from the present study demonstrate that systemic administration of PTH, SR and ZA could prevent bone loss, while a single dose of ZA has a better effect on preventing ovariectomy-induced osteoporosis than either PTH or SR.


Assuntos
Conservadores da Densidade Óssea , Osteoporose , Ovariectomia , Hormônio Paratireóideo , Tiofenos , Ácido Zoledrônico , Animais , Conservadores da Densidade Óssea/farmacologia , Feminino , Osteoporose/etiologia , Osteoporose/prevenção & controle , Ovariectomia/efeitos adversos , Hormônio Paratireóideo/farmacologia , Ratos , Ratos Sprague-Dawley , Tiofenos/farmacologia , Microtomografia por Raio-X , Ácido Zoledrônico/farmacologia
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