Biomedical subjects

Francisca Lago

Publications and source records attributed to Francisca Lago.

14 recordsLinked to original sources

PubMed2026

Relaxin-2: Shaping the Proteomic Landscape of Skeletal Muscle Physiology, Glucose Trafficking, and Mitochondrial Function in Rat.

Relaxin-2 is a hormone with robust beneficial effects on the heart and blood vessels and potential as a therapy for cardiovascular (CV) disease. Considering the interorgan communication between skeletal muscle and heart, and the relation between muscle quality/composition and CV events, we hypothesize that relaxin-2 may regulate skeletal muscle physiology and metabolism. We aim to evaluate the impact of relaxin-2 on the proteome of skeletal muscle from healthy Sprague-Dawley rats. Animals were treated with 0.4 mg/kg/day of serelaxin (recombinant form of human relaxin-2) or vehicle (PBS) for 2 weeks employing subcutaneous osmotic minipumps. Skeletal muscle protein identification and quantification were performed by LC-MS/MS using a Data-Independent Acquisition (DIA)-Sequential Window Acquisition of All Theoretical Fragment Ion Spectra (SWATH) method. SWATH/MS quantitative analysis identified that relaxin-2 significantly decreased 95 proteins and significantly increased 32 proteins in rat skeletal muscle when compared to control rats. From these, 34 proteins were associated with muscle function, myogenesis, muscle differentiation and/or regeneration, 20 are mitochondrial proteins (six from the complexes of the electron transport chain), and 10 proteins participate in glucose metabolism. Qualitative data-dependent workflow analysis identified 35 proteins exclusive to the skeletal muscle of the relaxin-2-treated group: eight proteins related to processes of skeletal muscle function (size, ion homeostasis or organization of caveolae structures and cytoskeleton) and myogenesis, and two proteins involved in muscle differentiation. Our work highlighted for the first time the role of relaxin-2 in crucial processes of muscle physiology and energetic metabolism, which could influence several processes involved in myopathy and CV.

Animals↗

PubMed2006

One ancestor, several peptides post-translational modifications of preproghrelin generate several peptides with antithetical effects.

Preproghrelin is the polypeptide precursor of ghrelin. First discovered in gastric extract as a growth hormone releasing peptide and food intake modulator, it has more recently been revealed to have other physiological aspects. The fine molecular mechanisms of ghrelin biosynthesis show that this peptide is but one piece of a puzzle which contains many other peptides obtained from alternative splicing of the same gene or from extensive post-translational modifications. Recent developments have shown that pro-ghrelin cleavage generates another active peptide named obestatin with an intriguingly subtle but opposite physiological action to ghrelin. Noteworthy, and similar to ghrelin, which requires post-translational processing close to its amino terminus by acylation, the biological activity of the ghrelin-associated peptide obestatin also depends on modification, but by amidation at its carboxyl terminus. In this review we will summarize the steps which led to the identification of pre-proghrelin gene products and will examine the significance and perspectives of the different peptides generated from the same ancestor gene.

Animals↗

PubMed2006

Doxazosin induces activation of GADD153 and cleavage of focal adhesion kinase in cardiomyocytes en route to apoptosis.

OBJECTIVE: The alpha 1-adrenoreceptor blocker doxazosin, which in the ALLHAT trial was associated with a greater risk of heart failure than the diuretic chlorthalidone, induces the apoptosis of human and murine cardiomyocytes regardless of alpha 1-adrenoreceptor blockade. We aimed to throw light on the mechanism of this process. METHODS: Murine cardiomyocytes (HL-1) and primary cultures of human and neonatal rat cardiomyocytes were treated with 25 micromol/L doxazosin for between 0.5 and 48 h. cDNA microarray analysis, real-time RT-PCR, and Western blotting were performed to detect possible changes in gene expression and/or activation of proteins that could be involved in doxazosin-induced apoptosis. RESULTS: Microarray analysis revealed changes in the expression of genes directly involved in the apoptotic end-stage of the cellular response to endoplasmic reticulum (ER) stress. Doxazosin considerably increased transcription and translation of gadd153, C/epb beta, and DOC-1 in cardiomyocytes as well as translocation of GADD153 to the nucleus, phosphorylation of p38 MAPK (a GADD153 activator), and the initial phosphorylation and subsequent cleavage of focal adhesion kinase (FAK). Experiments repeated following blockade of alpha(1)-adrenoreceptors showed no alteration of the above effects of doxazosin. CONCLUSION: Doxazosin induces the apoptosis of cardiomyocytes via the ER pathway, with increased production of C/EBP beta, GADD153 and DOC-1. Likewise it increases phosphorylation of the GADD153 activator p38 MAPK and induces first the phosphorylation, and then the cleavage, of FAK. These effects are not mediated by alpha 1-adrenoreceptors.

Adrenergic alpha-Antagonists↗

PubMed2006

[Gender differences in adiponectin and leptin expression in epicardial and subcutaneous adipose tissue. Findings in patients undergoing cardiac surgery].

INTRODUCTION AND OBJECTIVES: The high level of metabolic activity present in visceral adipose tissue is associated with the development of atherothrombosis. Subcutaneous adipose tissue secretes larger quantities of the adipocytokines leptin and adiponectin than visceral adipose tissue. Epicardial adipose tissue secretes inflammatory mediators, and the resulting proinflammatory activity is greater than that associated with subcutaneous adipose tissue. The aim of this study was to compare adiponectin and leptin expression in human epicardial and subcutaneous adipose tissue. METHODS: Samples of both epicardial and subcutaneous adipose tissue were taken from 46 patients who were undergoing heart surgery, coronary artery bypass surgery, or aortic or mitral valve replacement. Levels of protein and gene expression of leptin and adiponectin were assessed immunohistochemically and by RT-PCR, respectively. Levels of mRNA expression in the 2 adipose tissue types were compared by real-time quantitative PCR. RESULTS: Significant differences were found between adiponectin and leptin mRNA expression in epicardial and subcutaneous adipose tissue, with epicardial adipose tissue exhibiting lower levels of adiponectin and leptin expression. Moreover, adiponectin and leptin mRNA expression in epicardial adipose tissue was higher in women than men. CONCLUSIONS: Adiponectin and leptin expression is lower in epicardial than in subcutaneous adipose tissue. Moreover, there are differences in adiponectin and leptin expression in epicardial adipose tissue between women and men.

Adiponectin↗

PubMed2005

Adiponectin is synthesized and secreted by human and murine cardiomyocytes.

Adiponectin is thought to play a decisive role in the relationships among obesity, insulin resistance and cardiovascular risk. This study investigated whether cardiomyocytes synthesize and secrete adiponectin, and the effects of this hormone on cardiac cells. RT-PCR showed that mouse, rat and human cardiomyocytes produced mRNA for adiponectin and adiponectin receptors 1 and 2. Immunohistochemistry confirmed the presence of adiponectin in the cytoplasm of cultured cardiomyocytes, and radioimmunoassay showed that these cells secreted adiponectin into the culture medium. Exogenous adiponectin enhanced glucose and fatty acid uptake and induced AMPK phosphorylation in cultured cardiomyocytes. Our results demonstrate that adiponectin is synthesized and secreted by isolated murine and human cardiomyocytes, and suggest that the local production of this hormone by cardiomyocytes could be involved in the regulation of cardiac metabolism and function.

AMP-Activated Protein Kinases↗

PubMed2005

Signalling pathway involved in nitric oxide synthase type II activation in chondrocytes: synergistic effect of leptin with interleukin-1.

The objective of the present study was to investigate the effect of leptin, alone or in combination with IL-1, on nitric oxide synthase (NOS) type II activity in vitro in human primary chondrocytes, in the mouse chondrogenic ATDC5 cell line, and in mature and hypertrophic ATDC5 differentiated chondrocytes. For completeness, we also investigated the signalling pathway of the putative synergism between leptin and IL-1. For this purpose, nitric oxide production was evaluated using the Griess colorimetric reaction in culture medium of cells stimulated over 48 hours with leptin (800 nmol/l) and IL-1 (0.025 ng/ml), alone or combined. Specific pharmacological inhibitors of NOS type II (aminoguanidine [1 mmol/l]), janus kinase (JAK)2 (tyrphostin AG490 and Tkip), phosphatidylinositol 3-kinase (PI3K; wortmannin [1, 2.5, 5 and 10 micromol/l] and LY294002 [1, 2.5, 5 and 10 micromol/l]), mitogen-activated protein kinase kinase (MEK)1 (PD098059 [1, 5, 10, 20 and 30 micromol/l]) and p38 kinase (SB203580 [1, 5, 10, 20 and 30 micromol/l]) were added 1 hour before stimulation. Nitric oxide synthase type II mRNA expression in ATDC5 chondrocytes was investigated by real-time PCR and NOS II protein expression was analyzed by western blot. Our results indicate that stimulation of chondrocytes with IL-1 results in dose-dependent nitric oxide production. In contrast, leptin alone was unable to induce nitric oxide production or expression of NOS type II mRNA or its protein. However, co-stimulation with leptin and IL-1 resulted in a net increase in nitric oxide concentration over IL-1 challenge that was eliminated by pretreatment with the NOS II specific inhibitor aminoguanidine. Pretreatment with tyrphostin AG490 and Tkip (a SOCS-1 mimetic peptide that inhibits JAK2) blocked nitric oxide production induced by leptin/IL-1. Finally, wortmannin, LY294002, PD098059 and SB203580 significantly decreased nitric oxide production. These findings were confirmed in mature and hypertrophic ATDC5 chondrocytes, and in human primary chondrocytes. This study indicates that leptin plays a proinflammatory role, in synergy with IL-1, by inducing NOS type II through a signalling pathway that involves JAK2, PI3K, MEK-1 and p38 kinase.

Animals↗

PubMed2005

Leptin, from fat to inflammation: old questions and new insights.

Leptin is 16 kDa adipokine that links nutritional status with neuroendocrine and immune functions. Initially thought to be a satiety factor that regulates body weight by inhibiting food intake and stimulating energy expenditure, leptin is a pleiotropic hormone whose multiple effects include regulation of endocrine function, reproduction, and immunity. Leptin can be considered as a pro-inflammatory cytokine that belongs to the family of long-chain helical cytokines and has structural similarity with interleukin-6, prolactin, growth hormone, IL-12, IL-15, granulocyte colony-stimulating factor and oncostatin M. Because of its dual nature as a hormone and cytokine, leptin links the neuroendocrine and the immune system. The role of leptin in the modulation of immune response and inflammation has recently become increasingly evident. The increase in leptin production that occurs during infection and inflammation strongly suggests that leptin is a part of the cytokine network which governs the inflammatory-immune response and the host defense mechanisms. Leptin plays an important role in inflammatory processes involving T cells and has been reported to modulate T-helper cells activity in the cellular immune response. Several studies have implicated leptin in the pathogenesis of autoimmune inflammatory conditions, such as experimental autoimmune encephalomyelitis, type 1 diabetes, rheumatoid arthritis, and intestinal inflammation. Very recently, a key role for leptin in osteoarthritis has been demonstrated: leptin indeed exhibits, in concert with other pro-inflammatory cytokines, a detrimental effect on articular cartilage by promoting nitric oxide synthesis in chondrocytes. Here, we review the recent advances regarding leptin biology with a special focus on those actions relevant to the role of leptin in the pathophysiology of inflammatory processes and immune responses.

Animals↗

PubMed2005

Ghrelin, the same peptide for different functions: player or bystander?

Ghrelin is a recently discovered brain-gut peptide with two main physiological actions: growth hormone secretagogue activity and food intake inducer. Although its production is prevalently gastric, ghrelin is widely expressed in several tissues, where it might therefore act as a paracrine or autocrine factor. It is becoming clear that ghrelin is much more than a simple growth hormone secretagogue. In addition to its formerly envisaged role, ghrelin has other activities including stimulation of pituitary hormones secretion, modulation of food intake and control of energy metabolism, regulation of gastric and pancreatic activity, and cardiovascular and hemodynamic activities. In addition, modulation of cartilage and bone homeostasis, sleep and behavioral influences, and modulation of the immune system, as well as effects on cell proliferation, are other relevant actions of ghrelin. Thus, the peptide appears to be an important component of an integrated multifaceted regulatory system. In this review, we summarize several aspects of ghrelin biology and attempt to inform the reader with information regarding unexpected functions of this gastric peptide.

Acylation↗

PubMed2005

Leptin does not induce hypertrophy, cell cycle alterations, or production of MCP-1 in cultured rat and mouse cardiomyocytes.

BACKGROUND: Leptin has been proposed as an important mediator in cardiovascular pathophysiology. Patients with congestive heart failure (CHF) present high plasma leptin levels. CHF is generally preceded by myocardial remodeling involving hypertrophy, necrosis, and apoptosis. AIM: To investigate whether leptin causes hypertrophy or cell cycle alterations, or induces MCP-1 synthesis in cardiomyocytes. METHODS: Primary cultures of neonatal rat cardiomyocytes (PC) and murine cell line HL-1 were used. RT-PCR was used to identify Ob-Rb gene expression. Metabolic activity and proliferation of cardiomyocytes was studied using MTT and BrdU uptake, while apoptosis was assayed with Hoechst dye vital staining and flow cytometry. Measurement of the cell surface area was used to determine hypertrophy. MCP-1 levels were measured by ELISA. RESULTS: RT-PCR showed Ob-Rb mRNA expression in HL-1 cells. Exposure to leptin induced no changes in metabolic activity, proliferation, and apoptotic rates, and did not alter cell cycle in cardiomyocytes. Leptin did not increase cell size of cardiomyocytes, and MCP-1 synthesis was not detected in PC and HL-1 cells treated with leptin. CONCLUSION: This work shows that leptin does not induce changes in viability, proliferation, size or apoptosis of rat neonatal and HL-1 cardiomyocytes, and it does not induce MCP-1 secretion in these cells.

Animals↗

PubMed2004

Growth hormone releasing peptide (ghrelin) is synthesized and secreted by cardiomyocytes.

OBJECTIVE: Ghrelin, the endogenous ligand of growth hormone secretagogue receptor (GHS-R), acts on the pituitary and the hypothalamus to stimulate the release of growth hormone (GH) and promotes appetite and adiposity. It has also been reported to increase myocardial contractility, induce vasodilation, and protect against myocardial-infarction-induced heart failure. Though principally gastric in origin, it is also produced by other tissues. This work investigated whether cardiomyocytes synthesize and secrete ghrelin, and how its production in these cells responds to stress and exogenous apoptotic agents. METHODS: Ghrelin and its receptor expression was studied by RT-PCR, immunohistochemistry, and competitive binding studies in mouse adult cardiomyocyte cell line HL-1, and primary cultured human cardiomyocytes. Ghrelin accumulation in cardiomyocyte culture medium was measured by radioimmunoassay. Viability and apoptosis assays were carried on by MTT and Hoechst dye vital staining, respectively. RESULTS: RT-PCR showed that HL-1 cells produce mRNAs for both ghrelin and GHS-R, and that GHS-R1a is expressed in human cardiomyocytes; and competitive binding studies using (125)I-labelled ghrelin showed efficient constitutive expression of GHS-R at the surface of HL-1 cells. Immunohistochemistry confirmed the presence of ghrelin in the cytoplasm of HL-1 cells and of isolated human cardiomyocytes in primary culture. Radioimmunoassay showed that ghrelin was secreted by HL-1 cells and human cardiomyocytes into the culture medium. Ghrelin did not modify the viability of HL-1 cells subjected to 12-h starvation, but did protect against the apoptosis inducer cytosine arabinoside (AraC). Finally, production of ghrelin mRNA in HL-1 cardiomyocytes was reduced by AraC but increased if exposure to AraC was preceded by GH treatment. CONCLUSIONS: Ghrelin is synthesized and secreted by isolated murine and human cardiomyocytes, probably with paracrine/autocrine effects, and may be involved in protecting these cells from apoptosis.

Animals↗

PubMed2003

Ghrelin, a widespread hormone: insights into molecular and cellular regulation of its expression and mechanism of action.

The recent discovery of ghrelin, the endogenous ligand for the growth hormone secretagogue receptor, is the result of almost 25 years of research by many groups all around the world, and represents a milestone in our understanding of growth hormone secretion and energy homeostasis. This minireview is focused on recent studies on ghrelin, pointing out the cellular and molecular mechanisms involved in the gene expression of ghrelin since recent studies have unequivocally shown that ghrelin biological activity is dependent on a peculiar post-translational processing. Major interest in this peptide derived from the fact that, in addition to other effects, it is involved in the regulation of energy balance by inducing weight gain and reducing fat utilization. These activities are likely mediated by a CNS network of cells that is also modulated by other hormones such as leptin. Ghrelin has emerged as a premeal initiation factor that informs CNS about the status of the energy balance. The development of ghrelin analogs, agonists and antagonists, appears as a suitable approach for possible therapeutic intervention in a variety of disease states linked to alterations in body weight homeostasis.

Animals↗

PubMed2003

Ghrelin plasmatic levels in patients with fibromyalgia.

Ghrelin is a recently discovered 28 amino acid peptide that regulates GH secretion and energy homeostasis. In fibromyalgia (FM) there are alterations in the pituitary-hypothalamic axis, particularly in the growth hormone (GH) secretion pattern. Whether this anomalous secretion of GH pertains to abnormal levels of ghrelin is still unknown. The purpose of this study was to investigate plasma ghrelin levels in patients with fibromyalgia (FM) compared with healthy controls. Plasmatic ghrelin concentrations were determined by a double antibody radioimmunoassay in 19 patients with FM and 14 healthy controls. Compared with controls, patients with FM did not show any significant differences of ghrelin plasmatic levels. In conclusion, FM is not associated with deviation in ghrelin concentrations. Existing alterations in FM with respect to GH are unlikely due to circulating ghrelin.

Female↗

PubMed2003

Doxazosin induces apoptosis in cardiomyocytes cultured in vitro by a mechanism that is independent of alpha1-adrenergic blockade.

BACKGROUND: The alpha1-adrenoceptor-blocking antihypertensive doxazosin has been associated with increased risk of heart failure and is known to induce prostate cell apoptosis. We hypothesized that it might also induce apoptosis in cardiomyocytes. METHODS AND RESULTS: Hoechst dye vital staining and flow cytometry provided evidence that doxazosin induced apoptosis time- and dose-dependently in cardiomyocytes of the HL-1 cell line. TUNEL assays and 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) viability test confirmed that doxazosin induced DNA damage and cell death in these cells. MTT tests showed that doxazosin treatment decreased cell viability in primary cultures of neonatal rat cardiomyocytes, and Hoechst dye vital staining demonstrated doxazosin-induced apoptosis in primary cultures of human adult cardiomyocytes. The proapoptotic effect of doxazosin on cardiomyocytes seems not to depend on alpha1 blockade, because it was not modified by cotreatment with alpha- or beta-adrenergic agonists or with the irreversible alpha1-blocker phenoxybenzamine and because doxazosin also decreased the viability of NIH 3T3 cells, which lack alpha1-adrenoceptors. It also does not involve calcineurin, being unaffected by the presence of the calcineurin inhibitors cyclosporin A and FK506. Three other alpha1-blockers were also investigated; prazosin was proapoptotic, like doxazosin, but 5-methylurapidil and terazosin were not. CONCLUSIONS: The alpha1-blockers doxazosin and prazosin induce the apoptosis of cardiomyocytes cultured in vitro by a mechanism that is independent of alpha1 blockade and calcineurin.

3T3 Cells↗

PubMedDate not supplied

Leptin: a metabolic hormone that functions like a proinflammatory adipokine.

Initially described as a satiety factor with neuroendocrine properties, leptin has been shown to regulate immune and inflammatory processes. Mainly produced by white adipose tissue, this hormone was first known to regulate energy homeostasis by inhibiting food intake and by upregulating energy consumption. Leptin is a dual molecule: apart from its actions as a hormone involved in energy homeostasis, increasing evidence suggests that leptin is a novel proinflammatory adipocyte-derived factor that operates in the cytokine network by linking immune and inflammatory processes to the neuroendocrine system. In fact, recent findings have shown that leptin regulates and participates both in immune homeostasis and inflammatory processes not only by acting as a modulator of T-cell activity, but also by playing a key role in a host of autoimmune inflammatory conditions such as autoimmune encephalomyelitis, type 1 diabetes, bowel inflammation and articular degenerative diseases such as osteoarthritis and rheumatoid arthritis. This review will more closely address leptin's cytokine properties rather than its role as a metabolic hormone by focusing on its biological actions in inflammatory processes, specifically those related to degenerative inflammatory diseases of the joints.

Adiponectin↗