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1.
BMC Pregnancy Childbirth ; 24(1): 359, 2024 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-38745117

RESUMEN

BACKGROUND: Respectful Maternal and Neonatal Care (RMNC) maintains and respects a pregnant person's dignity, privacy, informed choice, and confidentiality free from harm and mistreatment. It strives for a positive pregnancy and post-pregnancy care experiences for pregnant people and their families, avoiding any form of obstetric violence. Though RMNC is now widely accepted as a priority in obstetric care, there is a gap in resources and support tools for healthcare wproviders to clearly understand the issue and change long-established practices such as non-humanized caesarean sections. MSI Reproductive Choices (MSI) manages 31 maternities across 7 countries with a zero-tolerance approach towards disrespectful maternity care and obstetric violence. MSI developed and implemented a hybrid training package, which includes an online module and 1-day in-person workshop that allows healthcare providers to explore their beliefs and attitudes towards RMNC. It leverages methodologies used in Values-Clarification-Attitudes-Transformation (VCAT) workshops and behaviour change approaches. METHODS: The impact of this training intervention was measured from the healthcare providers' and patients' perspectives. Patient experience of (dis)respectful care was collected from a cross-sectional survey of antenatal and postnatal patients attending MSI maternities in Kenya and Tanzania before and following the RMNC training intervention. Healthcare providers completed pre- and post-workshop surveys at day 1, 90 and 180 to measure any changes in their knowledge, attitudes and perception of intended behaviours regarding RMNC. RESULTS: The results demonstrate that healthcare provider knowledge, attitudes and perceived RMNC practices can be improved with this training interventions. Patients also reported a more positive experience of their maternity care following the training. CONCLUSION: RMNC is a patient-centred care priority in all MSI maternities. The training bridges the gap in resources currently available to support changes in healthcare wproviders' attitudes and behaviours towards provision of RMNC. Ensuring health system infrastructure supports compassionate obstetric care represents only the first step towards ensuring RMNC. The results from the evaluation of this RMNC provider training intervention demonstrates how healthcare provider knowledge and attitudes may represent a bottleneck to ensuring RMNC that can be overcome using VCAT and behaviour change approaches.


Asunto(s)
Actitud del Personal de Salud , Personal de Salud , Respeto , Humanos , Kenia , Tanzanía , Femenino , Embarazo , Adulto , Estudios Transversales , Personal de Salud/educación , Personal de Salud/psicología , Servicios de Salud Materna/normas , Recién Nacido , Relaciones Profesional-Paciente , Adulto Joven
2.
Antioxidants (Basel) ; 13(3)2024 Mar 05.
Artículo en Inglés | MEDLINE | ID: mdl-38539848

RESUMEN

The transcription factor WRKY53 of the model plant Arabidopsis thaliana is an important regulator of leaf senescence. Its expression, activity and degradation are tightly controlled by various mechanisms and feedback loops. Hydrogen peroxide is one of the inducing agents for WRKY53 expression, and a long-lasting intracellular increase in H2O2 content accompanies the upregulation of WRKY53 at the onset of leaf senescence. We have identified different antioxidative enzymes, including catalases (CATs), superoxide dismutases (SODs) and ascorbate peroxidases (APXs), as protein interaction partners of WRKY53 in a WRKY53-pulldown experiment at different developmental stages. The interaction of WRKY53 with these enzymes was confirmed in vivo by bimolecular fluorescence complementation assays (BiFC) in Arabidopsis protoplasts and transiently transformed tobacco leaves. The interaction with WRKY53 inhibited the activity of the enzyme isoforms CAT2, CAT3, APX1, Cu/ZuSOD1 and FeSOD1 (and vice versa), while the function of WRKY53 as a transcription factor was also inhibited by these complex formations. Other WRKY factors like WRKY18 or WRKY25 had no or only mild inhibitory effects on the enzyme activities, indicating that WRKY53 has a central position in this crosstalk. Taken together, we identified a new additional and unexpected feedback regulation between H2O2, the antioxidative enzymes and the transcription factor WRKY53.

3.
J Clin Invest ; 133(6)2023 03 15.
Artículo en Inglés | MEDLINE | ID: mdl-36719747

RESUMEN

Myeloproliferative neoplasms (MPNs) are characterized by the activated JAK2/STAT pathway. Pleckstrin-2 (Plek2) is a downstream target of the JAK2/STAT5 pathway and is overexpressed in patients with MPNs. We previously revealed that Plek2 plays critical roles in the pathogenesis of JAK2-mutated MPNs. The nonessential roles of Plek2 under physiologic conditions make it an ideal target for MPN therapy. Here, we identified first-in-class Plek2 inhibitors through an in silico high-throughput screening approach and cell-based assays, followed by the synthesis of analogs. Plek2-specific small-molecule inhibitors showed potent inhibitory effects on cell proliferation. Mechanistically, Plek2 interacts with and enhances the activity of Akt through the recruitment of downstream effector proteins. The Plek2-signaling complex also includes Hsp72, which protects Akt from degradation. These functions were blocked by Plek2 inhibitors via their direct binding to the Plek2 dishevelled, Egl-10 and pleckstrin (DEP) domain. The role of Plek2 in activating Akt signaling was further confirmed in vivo using a hematopoietic-specific Pten-knockout mouse model. We next tested Plek2 inhibitors alone or in combination with an Akt inhibitor in various MPN mouse models, which showed significant therapeutic efficacies similar to that seen with the genetic depletion of Plek2. The Plek2 inhibitor was also effective in reducing proliferation of CD34-positive cells from MPN patients. Our studies reveal a Plek2/Akt complex that drives cell proliferation and can be targeted by a class of antiproliferative compounds for MPN therapy.


Asunto(s)
Trastornos Mieloproliferativos , Neoplasias , Ratones , Animales , Proteínas Proto-Oncogénicas c-akt/genética , Proteínas Proto-Oncogénicas c-akt/metabolismo , Transducción de Señal , Trastornos Mieloproliferativos/tratamiento farmacológico , Trastornos Mieloproliferativos/genética , Trastornos Mieloproliferativos/patología , Proliferación Celular , Janus Quinasa 2/metabolismo
4.
Proc Natl Acad Sci U S A ; 119(50): e2214396119, 2022 12 13.
Artículo en Inglés | MEDLINE | ID: mdl-36472957

RESUMEN

Osteoporosis is a major public health problem. Currently, there are no orally available therapies that increase bone formation. Intermittent parathyroid hormone (PTH) stimulates bone formation through a signal transduction pathway that involves inhibition of salt-inducible kinase isoforms 2 and 3 (SIK2 and SIK3). Here, we further validate SIK2/SIK3 as osteoporosis drug targets by demonstrating that ubiquitous deletion of these genes in adult mice increases bone formation without extraskeletal toxicities. Previous efforts to target these kinases to stimulate bone formation have been limited by lack of pharmacologically acceptable, specific, orally available SIK2/SIK3 inhibitors. Here, we used structure-based drug design followed by iterative medicinal chemistry to identify SK-124 as a lead compound that potently inhibits SIK2 and SIK3. SK-124 inhibits SIK2 and SIK3 with single-digit nanomolar potency in vitro and in cell-based target engagement assays and shows acceptable kinome selectivity and oral bioavailability. SK-124 reduces SIK2/SIK3 substrate phosphorylation levels in human and mouse cultured bone cells and regulates gene expression patterns in a PTH-like manner. Once-daily oral SK-124 treatment for 3 wk in mice led to PTH-like effects on mineral metabolism including increased blood levels of calcium and 1,25-vitamin D and suppressed endogenous PTH levels. Furthermore, SK-124 treatment increased bone formation by osteoblasts and boosted trabecular bone mass without evidence of short-term toxicity. Taken together, these findings demonstrate PTH-like effects in bone and mineral metabolism upon in vivo treatment with orally available SIK2/SIK3 inhibitor SK-124.


Asunto(s)
Inhibición Psicológica , Osteogénesis , Humanos , Ratones , Animales , Plomo , Proteínas Serina-Treonina Quinasas/genética
5.
BMC Plant Biol ; 21(1): 470, 2021 Oct 14.
Artículo en Inglés | MEDLINE | ID: mdl-34649524

RESUMEN

BACKGROUND: The high susceptibility of European grapevine cultivars (Vitis vinifera) to downy mildew (Plasmopara viticola) leads to the intensive use of fungicides in viticulture. To reduce this input, breeding programs have introgressed resistance loci from wild Vitis species into V. vinifera, resulting in new fungus-resistant grapevine cultivars (FRC). However, little is known about how these different resistance loci confer resistance and what the potential reduction in fungicide applications are likely to be if these FRCs are deployed. To ensure a durable and sustainable resistance management and breeding, detailed knowledge about the different defense mechanisms mediated by the respective Rpv (Resistance to P. viticola) resistance loci is essential. RESULTS: A comparison of the resistance mechanisms mediated by the Rpv3-1, Rpv10 and/or Rpv12-loci revealed an early onset of programmed cell death (PCD) at 8 hours post infection (hpi) in Rpv12-cultivars and 12 hpi in Rpv10-cultivars, whereas cell death was delayed in Rpv3-cultivars and was not observed until 28 hpi. These temporal differences correlated with an increase in the trans-resveratrol level and the formation of hydrogen peroxide shortly before onset of PCD. The differences in timing of onset of Rpv-loci specific defense reactions following downy mildew infection could be responsible for the observed differences in hyphal growth, sporulation and cultivar-specific susceptibility to this pathogen in the vineyard. Hereby, Rpv3- and Rpv12/Rpv3-cultivars showed a potential for a significant reduction of fungicide applications, depending on the annual P. viticola infection pressure and the Rpv-loci. Furthermore, we report on the discovery of a new P. viticola isolate that is able to overcome both Rpv3- and Rpv12-mediated resistance. CONCLUSION: This study reveals that differences in the timing of the defense reaction mediated by the Rpv3-, Rpv10- and Rpv12-loci, result in different degrees of natural resistance to downy mildew in field. Vineyard trials demonstrate that Rpv12/Rpv3- and Rpv3-cultivars are a powerful tool to reduce the dependence of grape production on fungicide applications. Furthermore, this study indicates the importance of sustainable breeding and plant protection strategies based on resistant grapevine cultivars to reduce the risk of new P. viticola isolates that are able to overcome the respective resistance mechanism.


Asunto(s)
Resistencia a la Enfermedad/genética , Oomicetos/fisiología , Enfermedades de las Plantas/inmunología , Proteínas de Plantas/metabolismo , Vitis/genética , Apoptosis , Fungicidas Industriales/farmacología , Sitios Genéticos/genética , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/parasitología , Hojas de la Planta/genética , Hojas de la Planta/inmunología , Hojas de la Planta/parasitología , Proteínas de Plantas/genética , Vitis/inmunología , Vitis/parasitología
6.
Ann Biomed Eng ; 49(9): 2412-2420, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34002287

RESUMEN

Bladder cancer (BC) is the main disease in the urinary tract with a high recurrence rate and it is diagnosed by cystoscopy (CY). To train the CY procedures, a realistic bladder phantom with correct anatomy and physiological properties is highly required. Here, we report a soft bladder phantom (FlexBlad) that mimics many important features of a human bladder. Under filling, it shows a large volume expansion of more than 300% with a tunable compliance in the range of 12.2 ± 2.8 - 32.7 ± 5.4 mL cmH2O-1 by engineering the thickness of the bladder wall. By 3D printing and multi-step molding, detailed anatomical structures are represented on the inner bladder wall, including sub-millimeter blood vessels and reconfigurable bladder tumors. Endoscopic inspection and tumor biopsy were successfully performed. A multi-center study was carried out, where two groups of urologists with different experience levels executed consecutive CYs in the phantom and filled in questionnaires. The learning curves reveal that the FlexBlad has a positive effect in the endourological training across different skill levels. The statistical results validate the usability of the phantom as a valuable educational tool, and the dynamic feature expands its use as a versatile endoscopic training platform.


Asunto(s)
Fantasmas de Imagen , Vejiga Urinaria/diagnóstico por imagen , Adulto , Anciano , Cistoscopía , Humanos , Persona de Mediana Edad , Impresión Tridimensional , Tomografía Computarizada por Rayos X , Neoplasias de la Vejiga Urinaria/diagnóstico por imagen
7.
Micromachines (Basel) ; 10(4)2019 Mar 28.
Artículo en Inglés | MEDLINE | ID: mdl-30925719

RESUMEN

Laser induced forward transfer (LIFT) is a flexible digital printing process for maskless, selective pattern transfer, which uses single laser pulses focused through a transparent carrier substrate onto a donor layer to eject a tiny volume of the donor material towards a receiver substrate. Here, we present an advanced method for the high-resolution micro printing of bio-active detection chemicals diluted in a viscous buffer solution by transferring droplets with precisely controllable volumes using blister-actuated LIFT (BA-LIFT). This variant of the LIFT process makes use of an intermediate polyimide layer partially ablated by the laser pulses. The expanding gaseous ablation products lead to blisters in the polyimide and ejection of droplets from the subjacent viscous solution layer. A relative movement of donor and receiver substrates for the transfer of partially overlapping pixels is realized with a custom-made positioning system. Using a specially developed donor ink containing bio-active components presented method allows to transfer droplets with well controllable volumes between 20 fL and 6 pL, which is far more precise than other methods like inkjet or contact printing. The usefulness of the process is demonstrated by locally functionalizing laser-structured nitrocellulose paper-like membranes to form a multiparametric lateral flow test. The recognition zones localized within parallel micro channels exhibit a well-defined and homogeneous color change free of coffee-ring patterns, which is of utmost importance for reliable optical readout in miniature multiparametric test systems.

8.
Front Med (Lausanne) ; 5: 268, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30320114

RESUMEN

An 83-year-old patient developed erosions and a blister of the gingival mucous membrane, 6 months after discontinuation of the anti-programmed death-1 (anti PD-1) pembrolizumab therapy administered for 10 months for a metastatic melanoma. A diagnosis of mild mucous membrane pemphigoid (MMP) was made. Complete remission of MMP was rapidly obtained with minimal therapy (doxycycline). MMP remained in complete remission after a 3-month follow-up since discontinuation of the doxycycline therapy and no evidence of relapse of the melanoma was observed after a 14-month follow-up since discontinuation of the pembrolizumab therapy. The widespread use of anti PD-1 and anti-programmed death-ligand-1 (PD-L1) in several malignancies reveals new adverse events. MMP describes a group of chronic, inflammatory, mucous membrane-predominant, subepithelial auto-immune blistering diseases. It is clinically distinct from bullous pemphigoid another autoimmune blistering disease but shares some immunological similarities with it. Twenty-nine cases of bullous pemphigoid associated with anti PD-1/PD-L1 have been reported in the literature and one of MMP. Here, we described the case of a MMP developed after pembrolizumab and discussed the accountability of anti PD-1/PD-L1 in our case and the previous reported bullous pemphigoid and MMP cases using the Begaud system scoring.

9.
Anal Bioanal Chem ; 410(3): 863-868, 2018 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-28971240

RESUMEN

Lateral flow type detection is becoming interesting not only in regions with a poor medical infrastructure but also for practitioners in day-to-day clinical work or for veterinary control in case of possible epidemics. In this work, we describe the first steps of development of a multi-channel strip with potential internal calibration of multiparametric and colorimetric lateral flow assays for the simultaneous detection of the lipopolysaccharides (LPS) of Salmonella typhimurium (S. typhimurium) and Salmonella enteritidis (S. enteritidis). We structured four channels in the nitrocellulose membrane with a Yb:KGW solid-state femtosecond laser ("cold" ablation process) to form distinct tracks of porous material and used gold nanoparticles for the labeling of the antibodies. In addition, calibration curves of the spot intensities of both serovars are presented, and it was shown that no cross reactivity between the different capture antibodies and LPS occurred. Finally, we detected LPS of both Salmonella serovars simultaneously. The color changes (spot intensities of the reaction zones) were evaluated using the open-source image-processing program ImageJ. Graphical abstract Multiparametric testing, strip A was tested with LPS S. enteritidis ( c=0.01 g/L) and LPS S.typhimurium ( c=0.0001 g/L), strip B with LPS S. enteritidis ( c=0.001 g/L) and LPS S. typhimurium ( c=0.001g/L) and strip C with LPS S. enteritidis (c=0.0001 g/L) and LPS S. typhimurium ( c=0.01 g/L), and read-out.


Asunto(s)
Colorimetría/instrumentación , Lipopolisacáridos/análisis , Sistemas de Atención de Punto , Infecciones por Salmonella/microbiología , Salmonella enteritidis/aislamiento & purificación , Salmonella typhimurium/aislamiento & purificación , Colodión/química , Diseño de Equipo , Humanos , Inmunoensayo/instrumentación , Membranas Artificiales , Papel , Infecciones por Salmonella/diagnóstico
10.
J Toxicol Pathol ; 29(1 Suppl): 1S-125S, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-26973378

RESUMEN

The INHAND (International Harmonization of Nomenclature and Diagnostic Criteria for Lesions in Rats and Mice) project is a joint initiative of the Societies of Toxicologic Pathology from Europe (ESTP), Great Britain (BSTP), Japan (JSTP), and North America (STP) to develop an internationally accepted nomenclature and diagnostic criteria for nonproliferative and proliferative lesions in laboratory animals. The purpose of this publication is to provide a standardized nomenclature and diagnostic criteria for classifying lesions in the digestive system including the salivary glands and the exocrine pancreas of laboratory rats and mice. Most lesions are illustrated by color photomicrographs. The standardized nomenclature, the diagnostic criteria, and the photomicrographs are also available electronically on the Internet (http://www.goreni.org/). Sources of material included histopathology databases from government, academia, and industrial laboratories throughout the world. Content includes spontaneous and age related lesions as well as lesions induced by exposure to test items. Relevant infectious and parasitic lesions are included as well. A widely accepted and utilized international harmonization of nomenclature and diagnostic criteria for the digestive system will decrease misunderstandings among regulatory and scientific research organizations in different countries and provide a common language to increase and enrich international exchanges of information among toxicologists and pathologists.

11.
Clin Infect Dis ; 62(7): 903-905, 2016 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-26679622

RESUMEN

We report 2 cases of Ebola viral disease (EVD) in pregnant women who survived, initially with intact pregnancies. Respectively 31-32 days after negativation of the maternal blood EVD-polymerase chain reaction (PCR) both patients delivered a stillborn fetus with persistent EVD-PCR amniotic fluid positivity.


Asunto(s)
Fiebre Hemorrágica Ebola , Complicaciones Infecciosas del Embarazo , Adulto , Líquido Amniótico/virología , Femenino , Sangre Fetal/virología , Humanos , Placenta/virología , Embarazo , Mortinato , Adulto Joven
12.
Stomatos ; 21(40)jan. jun. 2015.
Artículo en Inglés | LILACS | ID: biblio-1714

RESUMEN

The eruption cyst is a benign soft tissue anomaly that may occur during eruption of deciduous or permanent teeth. It is usually asymptomatic and its treatment involves clinical follow-up of dental eruption. However, it may become infected or cause discomfort and pain. In such cases, surgical treatment is recommended. The present report aimed to describe a clinical case of eruption cyst located on the deciduous mandibular incisors' area of a four-month-old female infant since her birth. After surgical treatment a change was observed in the position (rotation) of the tooth associated with the cystic lesion. Rotation of the mandibular incisor persisted during the deciduous dentition development.


O cisto de erupção é uma anomalia benigna de tecidos moles que pode ocorrer durante a erupção dos dentes permanentes ou decíduos. Ele é geralmente assintomático e seu tratamento envolve acompanhamento clínico da erupção dental. No entanto, ele pode se tornar infectado ou causar desconforto e dor. Em tais casos, é recomendado tratamento cirúrgico. O presente relato teve como objetivo descrever um caso clínico de cisto de erupção localizado na área dos incisivos inferiores decíduos presente em um bebê de quatro meses de idade desde seu nascimento. Após o tratamento cirúrgico foi observada uma mudança na posição (rotação) do dente associado com a lesão cística. A rotação do incisivo inferior persistiu durante o desenvolvimento da dentição decídua.


Asunto(s)
Lactante , Diente Primario , Erupción Dental , Quiste Odontogénico Calcificado , Lactancia Materna/efectos adversos
15.
Anal Bioanal Chem ; 406(17): 4033-51, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24817356

RESUMEN

This review is focused on methods for detecting small molecules and, in particular, the characterisation of their interaction with natural proteins (e.g. receptors, ion channels). Because there are intrinsic advantages to using label-free methods over labelled methods (e.g. fluorescence, radioactivity), this review only covers label-free techniques. We briefly discuss available techniques and their advantages and disadvantages, especially as related to investigating the interaction between small molecules and proteins. The reviewed techniques include well-known and widely used standard analytical methods (e.g. HPLC-MS, NMR, calorimetry, and X-ray diffraction), newer and more specialised analytical methods (e.g. biosensors), biological systems (e.g. cell lines and animal models), and in-silico approaches.


Asunto(s)
Proteínas/química , Animales , Técnicas Biosensibles , Cromatografía Liquida , Humanos , Ligandos , Espectrometría de Masas , Unión Proteica , Difracción de Rayos X
16.
Brain Lang ; 124(1): 22-33, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23274421

RESUMEN

This study explores oscillatory brain activity by means of event-related synchronization and desynchronization (%ERS/ERD) of EEG activity during the use of phonological and orthographic-morphological spelling strategies in L2 (English) and L1 (German) in native German speaking children. EEG was recorded while 33 children worked on a task requiring either phonological or orthographic-morphological spelling strategies. L2 processing elicited more theta %ERS than L1 processing (particularly at bilateral frontal and right posterior parietal sites) which might suggest a stronger involvement of semantic encoding and retrieval of the less familiar L2. The highest level of theta %ERS was revealed for the orthographic-morphological strategy in L2 which might indicate a more intense way of lexical retrieval compared to the phonological strategy in L2 and the orthographic-morphological strategy in L1. Analyses moreover revealed that phonological processing (both in L1 and L2) was associated with comparatively strong left-hemispheric %ERD in the upper alpha frequency band.


Asunto(s)
Sincronización de Fase en Electroencefalografía/fisiología , Multilingüismo , Fonética , Semántica , Ritmo alfa/fisiología , Niño , Femenino , Lóbulo Frontal/fisiología , Humanos , Lenguaje , Desarrollo del Lenguaje , Masculino , Psicometría , Ritmo Teta/fisiología , Percepción Visual/fisiología , Vocabulario
18.
J Appl Res Intellect Disabil ; 25(3): 282-7, 2012 May.
Artículo en Inglés | MEDLINE | ID: mdl-22489039

RESUMEN

BACKGROUND: Using mechanical restraints to protect a person who engaged in dangerous self-injury was decreased by manipulation of an establishing operation involving the client choosing the staff person who would work with her. MATERIALS AND METHODS: The client was a 28-year-old woman diagnosed with autism, bipolar disorder, static cerebral encephalopathy, moderate intellectual disabilities, hypotonia and musculoskeletal deformities. She had a history of biting herself and further bites could produce irreversible nerve damage. Mechanical restraints were applied when she bit, tried to bite herself or asked for them. RESULTS: When she was allowed to choose staff members, the use of mechanical restraint decreased. CONCLUSION: Reducing the time spent in mechanical restraint by giving the client a choice of staff members who would work with her demonstrates that such a choice may be an establishing operation. The usefulness of cumulative records and scatterplots to evaluate changes in the occurrence of self-injurious behaviour (SIB) and associated mechanical restraint is shown as are the advantages of using alternating treatment designs to assess the effectiveness of treatment conditions for someone who exhibits long-term cyclic behaviour.


Asunto(s)
Cuidadores/psicología , Trastornos Mentales/enfermería , Restricción Física/métodos , Conducta Autodestructiva/fisiopatología , Adulto , Trastorno Autístico/enfermería , Trastorno Autístico/psicología , Trastorno Bipolar/enfermería , Trastorno Bipolar/psicología , Epilepsia/enfermería , Epilepsia/psicología , Femenino , Humanos , Discapacidad Intelectual/enfermería , Discapacidad Intelectual/psicología , Trastornos Mentales/psicología , Hipotonía Muscular/enfermería , Anomalías Musculoesqueléticas/enfermería , Conducta Autodestructiva/enfermería
20.
Mol Cell Biol ; 30(12): 3071-85, 2010 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-20404086

RESUMEN

Beta-Catenin-dependent canonical Wnt signaling plays an important role in bone metabolism by controlling differentiation of bone-forming osteoblasts and bone-resorbing osteoclasts. To investigate its function in osteocytes, the cell type constituting the majority of bone cells, we generated osteocyte-specific beta-catenin-deficient mice (Ctnnb1(loxP/loxP); Dmp1-Cre). Homozygous mutants were born at normal Mendelian frequency with no obvious morphological abnormalities or detectable differences in size or body weight, but bone mass accrual was strongly impaired due to early-onset, progressive bone loss in the appendicular and axial skeleton with mild growth retardation and premature lethality. Cancellous bone mass was almost completely absent, and cortical bone thickness was dramatically reduced. The low-bone-mass phenotype was associated with increased osteoclast number and activity, whereas osteoblast function and osteocyte density were normal. Cortical bone Wnt/beta-catenin target gene expression was reduced, and of the known regulators of osteoclast differentiation, osteoprotegerin (OPG) expression was significantly downregulated in osteocyte bone fractions of mutant mice. Moreover, the OPG levels expressed by osteocytes were higher than or comparable to the levels expressed by osteoblasts during skeletal growth and at maturity, suggesting that the reduction in osteocytic OPG and the concomitant increase in osteocytic RANKL/OPG ratio contribute to the increased number of osteoclasts and resorption in osteocyte-specific beta-catenin mutants. Together, these results reveal a crucial novel function for osteocyte beta-catenin signaling in controlling bone homeostasis.


Asunto(s)
Huesos/metabolismo , Homeostasis , Osteocitos/metabolismo , Transducción de Señal , Proteínas Wnt/metabolismo , beta Catenina/metabolismo , Animales , Animales Recién Nacidos , Resorción Ósea/metabolismo , Huesos/patología , Recuento de Células , Pérdida del Embrión/metabolismo , Pérdida del Embrión/patología , Fémur/anomalías , Fémur/metabolismo , Fémur/patología , Eliminación de Gen , Ratones , Ratones Noqueados , Especificidad de Órganos , Osteoclastos/metabolismo , Osteoclastos/patología , Osteocitos/patología , Factores de Tiempo
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