Modulation of the K/BxN arthritis mouse model and the effector functions of human fibroblast-like synoviocytes by liver X receptors.

The role of liver X receptors (LXR) in rheumatoid arthritis (RA) remains controversial. We studied the effect of LXR agonists on fibroblast-like synoviocytes (FLS) from RA patients and the K/BxN arthritis model in LXRα and β double-deficient (Nr1h2/3) mice. Two synthetic LXR agonists, GW3965 and T0901317, were used to activate LXRs and investigate their effects on cell growth, proliferation and matrix metalloproteinases, and chemokine production in cultured FLS from RA patients.

Quantal Release Analysis of Electrochemically Active Molecules Using Single-Cell Amperometry.

Single-cell amperometry is a powerful technique that permits the detection of electrochemically active transmitters, such as catecholamines, histamine, or serotonin, released by exocytosis from secretory cells.Amperometry has two main characteristics that make it ideal for the study of exocytosis at the single-cell level with single-vesicle resolution quantal release. (i) It is noninvasive.

Glucagon-like peptide-1 receptor controls exocytosis in chromaffin cells by increasing full-fusion events.

Agonists for glucagon-like-peptide-1 receptor (GLP-1R) are currently used for the treatment of type 2 diabetes and obesity. Their benefits have been centered on pancreas and hypothalamus, but their roles in other organ systems are not well understood. We studied the action of GLP-1R on secretions of adrenal medulla.

HDL cholesterol efflux capacity and lipid profile in patients with systemic sclerosis.

Objective: It is well established that patients with systemic sclerosis (SSc) have a disrupted lipid profile and an increased cardiovascular risk. Cholesterol efflux capacity (CEC), the ability of high-density lipoprotein (HDL)-cholesterol to accept cholesterol from macrophages, has been linked to cardiovascular events. The aim of this study was to establish whether CEC and lipid profile were impaired in SSc patients with respect to controls and whether these changes were associated with disease-related data.

Differences in Capacity of High-Density Lipoprotein Cholesterol Efflux Between Patients With Systemic Lupus Erythematosus and Rheumatoid Arthritis.

Objective: Cholesterol efflux capacity (CEC) is the ability of high-density lipoprotein (HDL) cholesterol to accept cholesterol from macrophages. Lipid profiles and CEC appear to be altered in patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) due to disease activity and inflammation. CEC has been linked to cardiovascular events in the general population and to subclinical atherosclerosis in SLE and RA patients.

Impaired HDL cholesterol efflux capacity in systemic lupus erythematosus patients is related to subclinical carotid atherosclerosis.

Objectives: Lipid profiles appear to be altered in SLE patients due to disease activity and inflammation. Cholesterol efflux capacity (CEC) is the ability of high-density lipoprotein cholesterol to accept cholesterol from macrophages. CEC has been linked to cardiovascular events in the general population and is impaired in SLE patients.

HDL cholesterol efflux capacity is related to disease activity in psoriatic arthritis patients.

Objective: Cholesterol efflux capacity (CEC) is the ability of high-density lipoprotein (HDL) cholesterol to accept cholesterol from macrophages. CEC is linked to cardiovascular events in the general population, and it has been shown to be disrupted in inflammatory states. The aim of this study was to establish whether CEC is impaired in PsA patients and if this could be explained by disease-related features like disease activity.

Combining the lack of chromogranins with chronic L-DOPA treatment affects motor activity in mice.

We have tested whether the lack of chromogranins (Cgs) A and B could provoke CNS disorders when combined with an excess of dopamine. We chronically treated (over 6 months) mice lacking both chromogranins A and B (Cgs-KO) with a low oral dosage of L-DOPA/benserazide (10/2.5 mg/kg).

Effect of IL-6 Receptor Blockade on Proprotein Convertase Subtilisin/Kexin Type-9 and Cholesterol Efflux Capacity in Rheumatoid Arthritis Patients.

The aim of the work was to examine whether abnormalities in the lipid profile that tocilizumab (TCZ), an anti-IL-6 receptor Ab, exerts in rheumatoid arthritis (RA) patients is related to changes in either proprotein convertase subtilisin/kexin-9 (PCSK9) serum concentrations or in serum cholesterol efflux capacity (CEC). TOCRIVAR is a one-year prospective clinical trial that analyzes the influence of TCZ on cardiovascular risk factors. Twenty-seven RA patients receiving TCZ (8 mg/kg IV/q4w) were assessed at baseline and weeks 12, 24, and 52.

Electrochemical Investigation of the Interaction between Catecholamines and ATP.

The study of the colligative properties of adenosine 5'-triphosphate (ATP) and catecholamines has received the attention of scientists for decades, as they could explain the capabilities of secretory vesicles (SVs) to accumulate neurotransmitters. In this Article, we have applied electrochemical methods to detect such interactions in vitro, at the acidic pH of SVs (pH 5.5) and examined the effect of compounds having structural similarities that correlate with functional groups of ATP (adenosine, phosphoric acid and sodium phosphate salts) and catecholamines (catechol).

Functional effects of proinflammatory factors present in Sjögren's syndrome salivary microenvironment in an in vitro model of human salivary gland.

Primary Sjögren's syndrome (pSS) is an autoimmune exocrinopathy in which the role that the immune response plays in reducing exocrine gland function, including the glandular microenvironment of cytokines, has not been fully understood. Epithelial cells from biopsies of human parotid gland (HPG) were used to establish a model of human salivary gland in vitro. In this model, the functional consequences of several proinflammatory soluble factors present in the pSS glandular microenvironment were assessed.

Isolation of mouse chromaffin secretory vesicles and their division into 12 fractions.

The study of chromaffin secretory vesicles (SVs) has contributed immensely to our understanding of exocytosis. These organelles, also called chromaffin granules, are a specific type of large dense secretory vesicle found in many endocrine cells and neurons. Traditionally, they have been isolated from bovine adrenal glands due to the large number of SVs that can be obtained from this tissue.

HDL cholesterol efflux capacity in rheumatoid arthritis patients: contributing factors and relationship with subclinical atherosclerosis.

Background: Lipid profiles appear to be altered in rheumatoid arthritis (RA) patients because of disease activity and inflammation. Cholesterol efflux capacity (CEC), which is the ability of high-density lipoprotein cholesterol to accept cholesterol from macrophages, has been linked not only to cardiovascular events in the general population but also to being impaired in patients with RA. The aim of this study was to establish whether CEC is related to subclinical carotid atherosclerosis in patients with RA.

ATP: The crucial component of secretory vesicles.

The colligative properties of ATP and catecholamines demonstrated in vitro are thought to be responsible for the extraordinary accumulation of solutes inside chromaffin cell secretory vesicles, although this has yet to be demonstrated in living cells. Because functional cells cannot be deprived of ATP, we have knocked down the expression of the vesicular nucleotide carrier, the VNUT, to show that a reduction in vesicular ATP is accompanied by a drastic fall in the quantal release of catecholamines. This phenomenon is particularly evident in newly synthesized vesicles, which we show are the first to be released.

The intravesicular cocktail and its role in the regulation of exocytosis.

The accumulation of neurotransmitters within secretory vesicles (SVs) far exceeds the theoretical tonic concentrations in the cytosol, a phenomenon that has captivated the attention of scientists for decades. For instance, chromaffin granules can accumulate close to molar concentrations of catecholamines, along with many other products like ATP, calcium, peptides, chromogranins, ascorbate, and other nucleotides. In this short review, we will summarize the interactions that are currently believed to occur between the elements that make up the vesicular cocktail in the acidic environment of SVs, and how they permit the accumulation of such high concentrations of certain components.

The role of chromogranins in the secretory pathway.

Chromogranins (Cgs) are acidic proteins implicated in several physiological processes, including the biogenesis and sorting of secretory vesicles, the generation of bioactive peptides, and the accumulation of soluble species inside large dense core vesicles (LDCV). Indeed, Cgs are the main protein component of the vesicular matrix in LDCV, and they are involved in the concentration of soluble species like neurotransmitters and calcium. Experiments using electrochemical techniques such amperometry, patch amperometry, and intracellular electrochemistry have clarified the functional roles of Cgs in the accumulation and release of catecholamines.

Prevention of neutrophil extravasation by α2-adrenoceptor-mediated endothelial stabilization.

Adrenergic receptors are expressed on the surface of inflammation-mediating cells, but their potential role in the regulation of the inflammatory response is still poorly understood. The objectives of this work were to study the effects of α2-adrenergic agonists on the inflammatory response in vivo and to determine their mechanism of action. In two mouse models of inflammation, zymosan air pouch and thioglycolate-induced peritonitis models, the i.

The interaction between chromogranin A and catecholamines governs exocytosis.

Chromogranins (Cgs) are acidic proteins that have been described in the large, dense core vesicles (LDCVs) of adrenal chromaffin cells and that have been shown to promote LDCV formation, even in nonsecretory cells. Catecholamines (CAs) are adsorbed by Cgs in vitro, and the absence of Cgs modifies the storage and exocytosis of CAs in chromaffin cells. In this study, we set out to assess the role of CgA in the accumulation and exocytosis of CAs in cells when the levels of CgA and CA are manipulated.

The functional role of chromogranins in exocytosis.

Chromogranins A (CgA) and B (CgB) are the main soluble proteins of large dense-core secretory vesicles (LDCVs). Using CgA- and CgB-knockout (KO) mice, we found that the absence of chromogranins A and B induces significant changes in catecholamine (CA) accumulation and the kinetics of exocytosis. By crossing these two knockout strains, we generated a viable and fertile double CgA/B-KO mouse in which the catecholamine content in chromaffin LDCVs was halved, and the secretory response significantly reduced.

Vesicular Ca(2+) mediates granule motion and exocytosis.

Secretory vesicles of chromaffin cells are acidic organelles that maintain an increasing pH gradient towards the cytosol (5.5 vs. 7.

Chromogranins A and B are key proteins in amine accumulation, but the catecholamine secretory pathway is conserved without them.

Chromogranins are the main soluble proteins in the large dense core secretory vesicles (LDCVs) found in aminergic neurons and chromaffin cells. We recently demonstrated that chromogranins A and B each regulate the concentration of adrenaline in chromaffin granules and its exocytosis. Here we have further studied the role played by these proteins by generating mice lacking both chromogranins.

Ouabain enhances exocytosis through the regulation of calcium handling by the endoplasmic reticulum of chromaffin cells.

The augmentation of neurotransmitter and hormone release produced by ouabain inhibition of plasmalemmal Na+/K+-ATPase (NKA) is well established. However, the mechanism underlying this action is still controversial. Here we have shown that in bovine adrenal chromaffin cells ouabain diminished the mobility of chromaffin vesicles, an indication of greater number of docked vesicles at subplasmalemmal exocytotic sites.

Fluorescent β-Blockers as Tools to Study Presynaptic Mechanisms of Neurosecretion.

Several, if not all adrenergic β-blockers (β-Bs), accumulate progressively inside secretory vesicles in a time- and concentration-dependent manner, and could be considered to be false neurotransmitters. This transmitter effect is most likely unrelated to their ability to block adrenergic receptors, but it could explain the delay in lowering arterial pressure in hypertensive patients. We have developed a new drug to monitor the accumulation of β-Bs inside living cells, RCTM-3, which fluoresces in the visible spectrum.

Chromogranins A and B as regulators of vesicle cargo and exocytosis.

Chromogranins (Cgs) are acidic proteins that have been implicated in several physiological processes such as vesicle sorting, the production of bioactive peptides and the accumulation of soluble species inside large dense core vesicles (LDCV). They constitute the main protein component in the vesicular matrix of LDCV. This latter characteristic of Cgs accounts for the ability of vesicles to concentrate catecholamines and Ca(2+).