The Thyroid Hormone Receptor (TR) beta-Selective Agonist GC-1 Inhibits Proliferation But Induces Differentiation and TR beta mRNA Expression in Mouse and Rat Osteoblast-Like Cells

Previous studies showed anabolic effects of GC-1, a triiodothyronine (T3) analogue that is selective for both binding and activation functions of thyroid hormone receptor (TR) beta 1 over TR alpha 1, on bone tissue in vivo. The aim of this study was to investigate the responsiveness of rat (ROS17/2.8) and mouse (MC3T3-E1) osteoblast-like cells to GC-1. As expected, T3 inhibited cellular proliferation and stimulated mRNA expression of osteocalcin or alkaline phosphatase in both cell lineages. Whereas equimolar doses of T3 and GC-1 equally affected these parameters in ROS17/2.8 cells, the effects of GC-1 were more modest compared to those of T3 in MC3T3-E1 cells. Interestingly, we showed that there is higher expression of TR alpha 1 than TR beta 1 mRNA in rat (similar to 20-90%) and mouse (similar to 90-98%) cell lineages and that this difference is even higher in mouse cells, which highlights the importance of TR alpha 1 to bone physiology and may partially explain the modest effects of GC-1 in comparison with T3 in MC3T3-E1 cells. Nevertheless, we showed that TR beta 1 mRNA expression increases (similar to 2.8- to 4.3-fold) as osteoblastic cells undergo maturation, suggesting a key role of TR beta 1 in mediating T3 effects in the bone forming cells, especially in mature osteoblasts. It is noteworthy that T3 and GC-1 induced TR beta 1 mRNA expression to a similar extent in both cell lineages (similar to 2- to 4-fold), indicating that both ligands may modulate the responsiveness of osteoblasts to T3. Taken together, these data show that TR beta selective T3 analogues have the potential to directly induce the differentiation and activity of osteoblasts.

Inhibition Mechanism of Rat alpha(3)beta(4) Nicotinic Acetylcholine Receptor by the Alzheimer Therapeutic Tacrine

Nicotinic acetylcholine receptors (nAChRs) were studied in detail in the past regarding their interaction with therapeutic and drug addiction related compounds. Using fast kinetic whole-cell recording, we have now studied effects of tacrine, an agent used clinically to treat Alzheimer`s disease, on currents elicited by activation of rat alpha(3)beta(4) nAChR heterologously expressed in KX alpha(3)beta(4)R2 cells. Characterization of receptor activation by nicotine used as agonist revealed a K(d) of 23 +/- 0.2 mu M and 4.3 +/- 1.3 for the channel opening equilibrium constant, Phi(-1). Experiments were performed to investigate whether tacrine is able to activate the alpha(3)beta(4) nAChR. Tacrine did not activate whole-cell currents in KX alpha(3)beta(4)R2 cells but inhibited receptor activity at submicromolar concentration. Dose response curves obtained with increasing agonist or inhibitor concentration revealed competitive inhibition of nAChRs by tacrine, with an apparent inhibition constant, K(I), of 0.8 mu M. The increase of Phi(-1) in the presence of tacrine suggests that the drug stabilizes a nonconducting open channel form of the receptor. Binding studies with TCP and MK-801 ruled out tacrine binding to common allosteric sites of the receptor. Our study suggests a novel mechanism for action of tacrine on nAChRs besides inhibition of acetylcholine esterase.

Nurse-led titration of angiotensin converting enzyme inhibitors, beta-adrenergic blocking agents, and angiotensin receptor blockers for people with heart failure with reduced ejection fraction

BACKGROUND: Heart failure is associated with high mortality and hospital readmissions. Beta-adrenergic blocking agents, angiotensin converting enzyme inhibitors (ACEIs), and angiotensin receptor blockers (ARBs) can improve survival and reduce hospital readmissions and are recommended as first-line therapy in the treatment of heart failure. Evidence has also shown that there is a dose-dependent relationship of these medications with patient outcomes. Despite this evidence, primary care physicians are reluctant to up-titrate these medications. New strategies aimed at facilitating this up-titration are warranted. Nurse-led titration (NLT) is one such strategy. OBJECTIVES: To assess the effects of NLT of beta-adrenergic blocking agents, ACEIs, and ARBs in patients with heart failure with reduced ejection fraction (HFrEF) in terms of safety and patient outcomes. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials in the Cochrane Library (CENTRAL Issue 11 of 12, 19/12/2014), MEDLINE OVID (1946 to November week 3 2014), and EMBASE Classic and EMBASE OVID (1947 to 2014 week 50). We also searched reference lists of relevant primary studies, systematic reviews, clinical trial registries, and unpublished theses sources. We used no language restrictions. SELECTION CRITERIA: Randomised controlled trials (RCTs) comparing NLT of beta-adrenergic blocking agents, ACEIs, and/or ARBs comparing the optimisation of these medications by a nurse to optimisation by another health professional in patients with HFrEF. DATA COLLECTION AND ANALYSIS: Two review authors (AD & JC) independently assessed studies for eligibility and risk of bias. We contacted primary authors if we required additional information. We examined quality of evidence using the GRADE rating tool for RCTs. We analysed extracted data by risk ratio (RR) with 95% confidence interval (CI) for dichotomous data to measure effect sizes of intervention group compared with usual-care group. Meta-analyses used the fixed-effect Mantel-Haenszel method. We assessed heterogeneity between studies by Chi(2) and I(2). MAIN RESULTS: We included seven studies (1684 participants) in the review. One study enrolled participants from a residential care facility, and the other six studies from primary care and outpatient clinics. All-cause hospital admission data was available in four studies (556 participants). Participants in the NLT group experienced a lower rate of all-cause hospital admissions (RR 0.80, 95% CI 0.72 to 0.88, high-quality evidence) and fewer hospital admissions related to heart failure (RR 0.51, 95% CI 0.36 to 0.72, moderate-quality evidence) compared to the usual-care group. Six studies (902 participants) examined all-cause mortality. All-cause mortality was also lower in the NLT group (RR 0.66, 95% CI 0.48 to 0.92, moderate-quality evidence) compared to usual care. Approximately 27 deaths could be avoided for every 1000 people receiving NLT of beta-adrenergic blocking agents, ACEIs, and ARBs. Only three studies (370 participants) reported outcomes on all-cause and heart failure-related event-free survival. Participants in the NLT group were more likely to remain event free compared to participants in the usual-care group (RR 0.60, 95% CI 0.46 to 0.77, moderate-quality evidence). Five studies (966 participants) reported on the number of participants reaching target dose of beta-adrenergic blocking agents. This was also higher in the NLT group compared to usual care (RR 1.99, 95% CI 1.61 to 2.47, low-quality evidence). However, there was a substantial degree of heterogeneity in this pooled analysis. We rated the risk of bias in these studies as high mainly due to a lack of clarity regarding incomplete outcome data, lack of reporting on adverse events associated with the intervention, and the inability to blind participants and personnel. Participants in the NLT group reached maximal dose of beta-adrenergic blocking agents in half the time compared with participants in usual care. Two studies reported on adverse events; one of these studies stated there were no adverse events, and the other study found one adverse event but did not specify the type or severity of the adverse event. AUTHORS' CONCLUSIONS: Participants in the NLT group experienced fewer hospital admissions for any cause and an increase in survival and number of participants reaching target dose within a shorter time period. However, the quality of evidence regarding the proportion of participants reaching target dose was low and should be interpreted with caution. We found high-quality evidence supporting NLT as one strategy that may improve the optimisation of beta-adrenergic blocking agents resulting in a reduction in hospital admissions. Despite evidence of a dose-dependent relationship of beta-adrenergic blocking agents, ACEIs, and ARBs with improving outcomes in patients with HFrEF, the translation of this evidence into clinical practice is poor. NLT is one strategy that facilitates the implementation of this evidence into practice.

Increased pancreatic islet mass is accompanied by activation of the insulin receptor substrate-2/serine-threonine kinase pathway and augmented cyclin D(2) protein levels in insulin-resistant rats

It is well known that glucocorticoids induce peripheral insulin resistance in rodents and humans. Here, we investigated the structural and ultrastructural modifications, as well as the proteins involved in beta-cell function and proliferation, in islets from insulin-resistant rats. Adult male Wistar rats were made insulin resistant by daily administration of dexamethasone (DEX; 1mg/kg, i.p.) for five consecutive days, whilst control (CTL) rats received saline alone. Structure analyses showed a marked hypertrophy of DEX islets with an increase of 1.7-fold in islet mass and of 1.6-fold in islet density compared with CTL islets (P < 0.05). Ultrastructural evaluation of islets revealed an increased amount of secreting organelles, such as endoplasmic reticulum and Golgi apparatus in DEX islets. Mitotic figures were observed in DEX islets at structural and ultrastructural levels. Beta-cell proliferation, evaluated at the immunohistochemical level using anti-PCNA (proliferating cell nuclear antigen), showed an increase in pancreatic beta-cell proliferation of 6.4-fold in DEX islets compared with CTL islets (P < 0.0001). Increases in insulin receptor substrate-2 (IRS-2), phosphorylated-serine-threonine kinase AKT (p-AKT), cyclin D(2) and a decrease in retinoblastoma protein (pRb) levels were observed in DEX islets compared with CTL islets (P < 0.05). Therefore, during the development of insulin resistance, the endocrine pancreas adapts itself increasing beta-cell mass and proliferation, resulting in an amelioration of the functions. The potential mechanisms that underlie these events involve the activation of the IRS-2/AKT pathway and activation of the cell cycle, mediated by cyclin D(2). These adaptations permit the maintenance of glycaemia at near-physiological ranges.

Mineral trioxide aggregate stimulates macrophages and mast cells to release neutrophil chemotactic factors: role of IL-1 beta, MIP-2 and LTB4

Objective. In the present study, the role of macrophages and mast cells in mineral trioxide aggregate (MTA)-induced release of neutrophil chemotactic factor was investigated.Study design. MTA suspension (50 mg/mL) was plated over inserts on macrophages or mast cells for 90 minutes. Untreated cells served as controls. Cells were washed and cultured for 90 minutes in RPMI without the stimuli. Macrophages and mast cell supernatants were injected intraperitoneally (0.5 mL/cavity), and neutrophil migration was assessed 6 hours later. In some experiments, cells were incubated for 30 minutes with dexamethasone (DEX, 10 mu M/well), BWA4C (BW, 100 mu M/well) or U75302 (U75, 10 mu M/well). The concentration of Leukotriene B-4 (LTB4) in the cell-free supernatant from mast cells and macrophage culture was measured by ELISA.Results. Supernatants from MTA-stimulated macrophages and mast cells caused neutrophil migration. The release of neutrophil chemotactic factor by macrophages and mast cells was significantly inhibited by DEX, BW, or U75. Macrophages and mast cells expressed mRNA for interleukin-1 (IL-1)beta and macrophage inflammatory protein-2 (MIP-2) and the pretreatment of macrophages and mast cells with DEX, BW, or U75 significantly altered IL-1 beta and MIP-2 mRNA expression. LTB4 was detected in the MTA-stimulated macrophage supernatant but not mast cells.Conclusions. MTA-induces the release of neutrophil chemotactic factor substances from macrophages and mast cells with participation of IL-1 beta, MIP-2, and LTB4. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010; 109: e135-e142)

Stress hormones increase cell proliferation and regulates interleukin-6 secretion in human oral squamous cell carcinoma cells

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Tumor Necrosis Factor alpha and Interleukin-1 beta Modulate Calcium and Nitric Oxide Signaling in Mechanically Stimulated Osteocytes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Propolis effects on pro-inflammatory cytokine production and Toll-like receptor 2 and 4 expression in stressed mice

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Interleukin-10 but not Transforming Growth Factor beta inhibits murine activated macrophages Paracoccidioides brasiliensis killing: Effect on H2O2 and NO production

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Mode of Peroxisome Proliferator-Activated Receptor gamma Activation by Luteolin

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

EFFECTS OF ENDOTOXIN, INTERLEUKIN-1-BETA AND PROSTAGLANDIN INJECTIONS ON FEVER RESPONSE IN BROILERS

1. The effect of endotoxin, interleukin-1 beta and prostaglandin on fever response was studied in 80 broilers (Hubbard strain). Endotoxin (E. coli, LPS) was injected iv (1.5 mu g/kg) and icv (1.5 mu g/bird); interleukin-1 (human recombinant IL-1 beta, 80 pg/bird) and prostaglandin E(2) (5 mu g/bird) were injected icv. Indomethacin (10 mg/kg, iv) pretreatment was also used before iv endotoxin injection. 2. The results showed that indomethacin was able to block the fever response induced by iv endotoxin injection, and IL-1 beta and PGE(2) were both effective in producing fever when injected icv. These data suggest a prostaglandin-mediated fever response by broilers, and also a strong evidence of the involvement of endogenous pyrogen (interleukin-1) in fever response in birds.

Glucose- and insulin-induced phosphorylation of the insulin receptor and its primary substrates IRS-1 and IRS-2 in rat pancreatic islets

The presence of tyrosine-phosphorylated proteins was studied in cultured rat pancreatic islets, Immunoblotting performed with total extracts of islets cultured in the presence of 1.8 or 5.6 mM glucose revealed at least three distinct tyrosine-phosphorylated bands (25 kDa, 95 kDa and 165-185 kDa). After 12 h incubation in medium containing 1.8 mM glucose, a pulse exposition to 11 or 22 mM glucose or to 10(-7) M insulin led to a substantial increase in the phosphorylation of all three bands, with no appearance of novel bands. Immunoprecipitation with specific antibodies demonstrated that the signal detected at 95 kDa corresponds to the beta subunit of the insulin receptor (IR) while the band at 165-185 kDa corresponds to the early substrates of the insulin receptor, IRS-1 and IRS-2. Immunoprecipitation with IRS-I or IRS-2 antisera detected their association with the lipid metabolizing enzyme phosphatidylinositol 3-kinase (PI 3-kinase), Thus, this is the first demonstration that elements involved in the insulin-signalling pathway of traditional target tissues are also present in pancreatic islets and are potentially involved in auto- and paracrine-signalling in this organ.

Proteinase-activated receptor-2 (PAR2) agonist causes periodontitis in rats

Proteinase-activated receptor-2 (PAR2) is a G-protein-coupled receptor that mediates cellular responses to extracellular proteinases. Since PAR2 is expressed by oral epithelial cells, osteoblasts, and gingival fibroblasts, where its activation releases interleukin-8, we hypothesized that PAR2 activation may participate in periodontal disease in vivo. We investigated the role of PAR2 activation in periodontal disease in rats. Radiographic and enzymatic (myeloperoxidase) analysis revealed that topical application of PAR2 agonist causes periodontitis but also exacerbates existing periodontitis, leading to significant alveolar bone loss and gingival granulocyte infiltration. Inhibition of matrix metalloproteinase (MMP) and cyclo-oxygenase (COX) decreased PAR2 agonist-induced periodontitis. More specifically, the overexpression of COX-1, COX-2, MMP-2, and MMP-9 in gingival tissues suggests that they are involved in PAR 2-induced periodontitis. In conclusion, PAR2 agonist causes periodontitis in rats through a mechanism involving prostaglandin release and MMP activation. Inhibition of PAR2 may represent a novel approach to modulate host response in periodontitis.