GPRC5B protects osteoarthritis by regulation of autophagy signaling

Osteoarthritis (OA) is one of the most common chronic diseases in the world. However, current treatment modalities mainly relieve pain and inhibit cartilage degradation, but do not promote cartilage regeneration. In this study, we show that G protein-coupled receptor class C group 5 member B (GPRC5B), an orphan G-protein-couple receptor, not only inhibits cartilage degradation, but also increases cartilage regeneration and thereby is protective against OA. We observed that Gprc5b deficient chondrocytes had an upregulation of cartilage catabolic gene expression, along with downregulation of anabolic genes in vitro. Furthermore, mice deficient in Gprc5b displayed a more severe OA phenotype in the destabilization of the medial meniscus (DMM) induced OA mouse model, with upregulation of cartilage catabolic factors and downregulation of anabolic factors, consistent with our in vitro findings. Overexpression of Gprc5b by lentiviral vectors alleviated the cartilage degeneration in DMM-induced OA mouse model by inhibiting cartilage degradation and promoting regeneration. We also assessed the molecular mechanisms downstream of Gprc5b that may mediate these observed effects and identify the role of protein kinase B (AKT)-mammalian target of rapamycin (mTOR)-autophagy signaling pathway. Thus, we demonstrate an integral role of GPRC5B in OA pathogenesis, and activation of GPRC5B has the potential in preventing the progression of OA.

Histomorphometry evaluation of bone anabolism promoted by prostaglandin E1 and its relation to hypercalcemia / Evaluación histomorfométrica del anabolismo óseo en la reparación promovida por la prostaglandina E1 y su relación con la hipercalcemia

Abstract Background: At present, parathyroid hormone is the only existing anabolic bone therapy but produces hypercalcemia. Prostaglandin E1 (PGE1) has been suggested as a bone anabolic agent that allows bone modeling formation without producing hypercalcemia. This study aimed to corroborate these PGE1 properties. Methods: For 22 days, rabbits (n = 30) were divided into three groups (n = 10 each group) and received intravenous solutions: vehicle (control group), palate disjunction + vehicle (sham group), and palate disjunction + 50 mg of PGE1 (PGE1 group). On days 1, 3, and 22, palatine suture X-rays were taken. On day 22, bone formation markers were analyzed, and the rabbits were sacrificed. Bone palate undecalcified samples were processed. Histomorphometry software was used to analyze bone parameters, and the mineralization front was stained with toluidine blue. Scalloped lines reflect remodeling-based bone formation (RBF), and smooth lines reflect modeling-based formation (MBF). Results: X-rays showed more significant palatal disjunction in the PGE1 group; this group exhibited significant calcitriol serum increments. Hypercalciuria was observed in the PGE1 group, and resorption markers (N-telopeptides) remained stable. Sutural bones in the PGE1 group exhibited significant anabolism in structural parameters. RBF was 20%, and MBF was 6% in the sham group; in the PGE1 group, RBF was 8.6%, and MBF was 17%. In the PGE1 group, mineralization was significantly accelerated, but resorption remained stable. Conclusions: This model suggests that PGE1 favors palate disjunction, calcitriol synthesis, and shortens the mineralization. Therefore, PGE1 is an important bone anabolic molecule predominantly of modeling-based form and no hypercalcemia.

Resumen Introducción: La hormona paratiroidea es la única molécula anabólica ósea, pero ocasiona hipercalcemia. La prostaglandina E1 (PGE1) sugiere ser un anabólico óseo con formación por modelación predominante y generalmente no ocasiona hipercalcemia. El objetivo de este estudio fue corroborar estas propiedades de la PGE1. Métodos: Por 22 días, 30 conejos divididos en tres grupos (n = 10 cada grupo) recibieron una solución por vía intravenosa: vehículo (grupo control), disyunción palatina más vehículo (grupo sham) y disyunción palatina más 50 mg de PGE1 (grupo PGE1). A los días 1, 3 y 22 se obtuvieron radiografías de la sutura palatina. En el día 22 se analizaron los marcadores bioquímicos de formación ósea y se sacrificó a los conejos. Las suturas y los huesos suturales se procesaron sin descalcificar. La evaluación histomorfométrica fue digitalizada y el frente de mineralización ósea se tiñó con azul de toluidina. Las líneas irregulares reflejan resorción (remodelación) y las líneas rectas no resorción (modelación). Resultados: Radiográficamente, la disyunción palatina fue mayor en el grupo PGE1. Este grupo mostró una hipercalcitonemia significativa, pero la calcemia y los marcadores resortivos (N-telopéptidos) se mantuvieron estables. Por histomorfometría, los huesos suturales del grupo PGE1 mostraron anabolismo significativo en parámetros estructurales. En el grupo sham, la remodelación ósea fue del 20% y la modelación fue del 6%; en el grupo PGE1, la remodelación fue del 8.6% y la modelación fue del 17%. En este mismo grupo, la mineralización fue significativamente acelerada, pero la resorción se mantuvo igual. Conclusiones: Este modelo sugiere que la PGE1 favorece la disyunción palatina y el aumento del calcitriol, y acelera la mineralización y el anabolismo óseo por modelación predominante sin hipercalcemia.

Hormônio do crescimento versus treinamento de força: alterações nas estruturas colágenas, lipídicas e glicídicas / Growth hormone (gh) versus strength training: changes in collagen, lipid and glucidic structures

O objetivo deste estudo foi avaliar o efeito da aplicação de hormônio do crescimento (Growth Hormone - GH) e treinamento de força (TF) na composição do tecido ósseo de ratos Wistar a partir da Espectroscopia Raman. 40 ratos machos foram distribuídos de forma aleatória em quatro grupos: controle (C [n=10]), controle a aplicação de GH (GHC [n=10]), treinamento de força (T [n=10]) e treinamento de força e aplicação de GH (GHT [n=10]). O treinamento foi composto por quatro séries de 10 saltos aquáticos, realizados três vezes por semana, com sobrecarga correspondente a 50% do peso corpóreo e duração de quatro semanas. O GH foi aplicado na dose de 0,2 UI/Kg em cada animal, três vezes por semana e em dias alternados. Ao final do experimento, os animais foram eutanasiados e coletados os fêmures direitos para realização da análise da composição óssea. A espectroscopia Raman (ER) foi utilizada para observar os seguintes compostos a partir de suas respectivas bandas: colágeno e fosfolipídio (1445 cm-1), colesterol (548 cm-1), glicerol (607 cm-1), glicose (913 cm-1), Pico de carboidrato (931 cm-1 ) e prolina (918 cm-1 ). Para a análise estatística, foram realizados os testes de normalidade de Shapiro-Wilk e análise de variâncias ANOVA one-way, seguida pelo pós-teste de Tukey. Os resultados revelaram aumento nas concentrações de colágeno e fosfolipidio, colesterol, glicerol, glicose, pico de carboidrato e prolina em todos os grupos experimentais, associados ou não à realização do ST e/ou aplicação de GH. Porém, somente o grupo T diferiu significativamente do grupo C (p<0,05). Conclui-se que todas intervenções puderam promover ganho no tecido ósseo, porém, somente o grupo T demonstrou diferença significativa nos compostos minerais analisados. (AU)

The objective of this study was to evaluate the effect of the application of growth hormone (GH) and strength training (TF) on the bone tissue composition of Wistar rats using Raman Spectroscopy. 40 male rats were randomly assigned to four groups: control (C [n = 10]), control the application of GH (GHC [n = 10]), strength training (T [n = 10]) and training of strength and application of GH (GHT [n = 10]). The training consisted of four series of 10 water jumps, performed three times a week, with an overload corresponding to 50% of body weight and lasting four weeks. GH was applied at a dose of 0.2 IU / kg to each animal, three times a week and on alternate days. After four weeks, the animals were euthanized and the right femurs were collected to carry out the analysis of the bone composition. Raman spectroscopy (ER) was used to observe the following compounds from their respective bands: collagen and phospholipid (1445 cm-1), cholesterol (548 cm-1), glycerol (607 cm-1), glucose (913 cm-1), Peak carbohydrate (931 cm-1), proline (918 cm-1). For statistical analysis, the Shapiro-Wilk normality tests and ANOVA One-Way analysis of variances were performed, followed by the Tukey post-test. The results revealed an increase in the concentrations of collagen and phospholipid, cholesterol, glycerol, glucose, peak carbohydrate and proline in all experimental groups, associated or not with the performance of ST and / or application of GH. However, only group T differed significantly from group C (p <0.05). It was concluded that all intervention could promote gain in bone tissue, however, only the T group showed a significant difference in the analyzed mineral compounds. (AU)

Metabolism and function of lipids in the adipose and liver tissues of production ruminants: a review / Función y metabolismo de ácidos grasos en el tejido adiposo y hepático de rumiantes en producción: una revisión / Função e metabolismo de ácidos graxos no tecido adiposo e hepático de ruminantes em produção: uma revisão

Abstract The adipose and liver tissues influence the fatty acid metabolism, being largely responsible for regulating their biosynthesis, degradation and storage in body tissues, as well as for their secretion in milk and meat production from ruminants. Therefore, a better understanding of the functionality of fatty acid metabolism in these tissues and the factors that affect it, could provide the basis for the design of productive strategies in ruminants. Thus, the aim of this review is to present a general overview of the functionality and metabolism of fatty acids in the adipose and liver tissues in production ruminants. From the review, it could be established that fatty acids and triglycerides are the main lipid types in adipose and liver tissues. Adipose tissue is the main energy storage site for both ruminants and non-ruminants. Adipose tissue is metabolically associated with liver tissue through an equilibrium that regulates the processes of β-oxidation, de novo synthesis, and fatty acid transport at a tissue level. Finally, it was established that the fatty acids metabolism in adipose and liver tissue is affected by several factors, including nutrition and level of dietary restriction, genetics, physiological state, and environment, being nutrition the main factor.

Resumen El tejido adiposo (TA) y hepático influencian el metabolismo de ácidos grasos (AG), al ser en gran parte los responsables de regular su biosíntesis, degradación y almacenamiento en tejidos corporales, como también de su secreción en leche y carne de animales en producción. De esta forma, un mejor entendimiento de la funcionalidad del metabolismo de AG en estos tejidos y los factores que lo afectan, podría dar las bases para el diseño de estrategias productivas en rumiantes. Así, el objetivo de esta revisión es presentar un panorama general de la funcionalidad y metabolismo de los AG en el TA y hepático en rumiantes de producción. A partir de la revisión, se pudo establecer, que el tipo de lípidos mayoritarios en TA y hepático, lo forman los AG y triglicéridos. El TA es el principal sitio de almacenamiento energético tanto en rumiantes como en no rumiantes. El TA se encuentra metabólicamente asociado con el tejido hepático mediante un equilibrio que regula los procesos de β-oxidación, síntesis de novo y transporte de AG a nivel tisular. Finalmente, se pudo establecer que el metabolismo de AG en TA y hepático es afectado por diversos factores, tales como la nutrición, nivel de restricción dietaria, genética, estado fisiológico y medio ambiente, de los cuales, la nutrición tiene el mayor impacto.

Resumo O tecido adiposo (TA) e hepático influenciam o metabolismo dos ácidos graxos (AG), sendo amplamente responsável pela regulação de biossíntese, degradação e armazenamento destes nos tecidos corporais, bem como sua secreção no leite e na carne de animais em produção. Desta forma, uma melhor compreensão da funcionalidade do metabolismo dos AG nesses tecidos e os fatores que o afetam, poderia fornecer a base para o planejamento de estratégias produtivas em ruminantes. Assim, o objetivo desta revisão é apresentar uma visão geral da funcionalidade e metabolismo dos AG no TA e hepático em ruminantes de produção. A partir da revisão, foi estabelecido que o tipo de lipídios principais no TA e hepático, são os AG e triglicerídeos. O TA é o principal local de armazenamento de energia para ruminantes e não ruminantes. O TA está metabolicamente associado ao tecido hepático através de um equilíbrio que regula os processos de β-oxidação, síntese de novo e transporte de AG ao nível dos tecidos. Finalmente, foi estabelecido que o metabolismo da AG no TA e no hepatócito é afetado por vários fatores, como nutrição, nível de restrição alimentar, genética, estado fisiológico e ambiente, dos quais a nutrição tem o maior impacto.

Metabolism in bacteria at low temperature: A recent report.

The adaptability of bacteria to extreme cold environments has been demonstrated from time to time by various investigators. Metabolic activity of bacteria at subzero temperatures is also evidenced. Recent studies indicate that bacteria continue both catabolic and anabolic activities at subzero temperatures. Implications of these findings are discussed.

Effects of Leptin on Proliferation, Anabolic and Catabolic Metabolism in Chondrocytes / 대한정형외과연구학회지

PURPOSE: Leptin may play an important role in the pathophysiology of osteoarthritis. However, the effect of letpin on the anabolic and catabolic metabolisms in chondrocytes remains unclearly elucidated. Therefore, the purpose of this study was to investigate the effect of leptin on proliferation, anabolic and catabolic metabolism of chondrocyte using ATDC5 chondrogenic cell line. MATERIALS AND METHODS: The effects of leptin on chodnrocyte proliferation, anabolic and catabolic meatabolism were examined in ATDC5 cells treated with leptin at varying concentrations(10, 100, 300, 600 ng/ml) for 24, 48, and 72 hours. The cell proliferation was evaluated by MTT assay. The anabolic and catabolic activities were assayed by RT-PCR for transforming growth factor-beta(TNF-alpha), proteoglycan-4 (PRG4), type- I collagen (type- I Col) and tumor necrosis factor-beta(TNF-alpha), matrix metalloproteinase -2 (MMP-2), respectively. RESULTS: Leptin treatment did not influence cell proliferation of chondrocyte regardless of concentration. TGF-beta expression was increased until 48 hours of leptin treatment compared to controls. Especially, it was significantly increased in leptin of 10 ng/ml and 100 ng/ml (P<0.05). PRG4 expression was not different between letpin treatment and controls. Type-I Col expression was decreased in dose- and time-dependent manner. Leptin of 10ng/ml significantly inhibited MMP-2 and TNF-alpha expressions compared to controls (P<0.05). CONCLUSION: This study shows that leptin at low concentration increases TGF-beta expression, but inhibits the expression of TNF-alpha and MMP-2. Also this study shows that leptin do not affect the cell proliferation of chondrocytes. These results suggest that leptin at low or physiological level contributes to the prevention of cartilage damage by stimulating anabolic activity and inhibiting catabolic activity of chondrocyte rather than chondrocyte regeneration by increasing cell proliferation.

Hormônio do crescimento e exercício físico: considerações atuais: [revisão] / Growth hormone and physical exercise: current considerations: [revision]

Embora o hormônio do crescimento (GH) seja um dos hormônios mais estudados, vários de seus aspectos fisiológicos ainda não estão integralmente esclarecidos, incluindo sua relação com o exercício físico. Estudos mais recentes têm aumentado o conhecimento a respeito dos mecanismos de ação do GH, podendo ser divididos em: 1) ações diretas, mediadas pela rede de sinalizações intracelulares, desencadeadas pela ligação do GH ao seu receptor na membrana plasmática; e 2) ações indiretas, mediadas principalmente pela regulação da síntese dos fatores de crescimento semelhantes à insulina (IGF). Tem sido demonstrado que o exercício físico é um potente estimulador da liberação do GH. A magnitude deste aumento sofre influência de diversos fatores, em especial, da intensidade e do volume do exercício, além do estado de treinamento. Atletas, normalmente, apresentam menor liberação de GH induzida pelo exercício que indivíduos sedentários ou pouco treinados. Evidências experimentais demonstram que o GH: 1) favorece a mobilização de ácidos graxos livres do tecido adiposo para geração de energia; 2) aumenta a capacidade de oxidação de gordura e 3) aumenta o gasto energético.

Although growth hormone (GH) is one of the most extensively studied hormones, various aspects related to this hormone have not been completely established, including its relationship with physical exercise. Recent studies have contributed to the understanding of the mechanisms of action of GH, which can be divided into 1) direct actions mediated by intracellular signals that are triggered by the binding of GH to its receptor on the plasma membrane, and 2) indirect actions mediated mainly by the regulation of the synthesis of insulin-like growth factors (IGF). Physical exercise has been shown to be a potent stimulator of GH release, especially in young men and women. The magnitude of this increase is influenced by several factors, especially the intensity and volume of exercise, in addition to training status. In this respect, athletes normally present a lower exercise-induced GH release than sedentary or poorly trained individuals. Experimental evidence indicates that GH may 1) favor the mobilization of free fatty acids from adipose tissue for energy generation, 2) increase the capacity of fat oxidation, and 3) increase energy expenditure.