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Dive into the research topics where Guilherme Oliveira Barbosa is active.

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Featured researches published by Guilherme Oliveira Barbosa.


Diabetes | 2016

n-3 Fatty Acids Induce Neurogenesis of Predominantly POMC-Expressing Cells in the Hypothalamus.

Lucas F. Nascimento; Gabriela Freitas Pereira de Souza; Joseane Morari; Guilherme Oliveira Barbosa; Carina Solon; Rodrigo Ferreira de Moura; Sheila Cristina Victório; Letícia M. Ignacio-Souza; Daniela S. Razolli; Hernandes F. Carvalho; Lício A. Velloso

Apoptosis of hypothalamic neurons is believed to play an important role in the development and perpetuation of obesity. Similar to the hippocampus, the hypothalamus presents constitutive and stimulated neurogenesis, suggesting that obesity-associated hypothalamic dysfunction can be repaired. Here, we explored the hypothesis that n-3 polyunsaturated fatty acids (PUFAs) induce hypothalamic neurogenesis. Both in the diet and injected directly into the hypothalamus, PUFAs were capable of increasing hypothalamic neurogenesis to levels similar or superior to the effect of brain-derived neurotrophic factor (BDNF). Most of the neurogenic activity induced by PUFAs resulted in increased numbers of proopiomelanocortin but not NPY neurons and was accompanied by increased expression of BDNF and G-protein–coupled receptor 40 (GPR40). The inhibition of GPR40 was capable of reducing the neurogenic effect of a PUFA, while the inhibition of BDNF resulted in the reduction of global hypothalamic cell. Thus, PUFAs emerge as a potential dietary approach to correct obesity-associated hypothalamic neuronal loss.


PLOS ONE | 2014

Transcription Factors Involved in Prostate Gland Adaptation to Androgen Deprivation

Rafaela Rosa-Ribeiro; Umar Nishan; Ramon Vidal; Guilherme Oliveira Barbosa; Leonardo Oliveira Reis; Carlos L. Cesar; Hernandes F. Carvalho

Androgens regulate prostate physiology, and exert their effects through the androgen receptor. We hypothesized that androgen deprivation needs additional transcription factors to orchestrate the changes taking place in the gland after castration and for the adaptation of the epithelial cells to the androgen-deprived environment, ultimately contributing to the origin of castration-resistant prostate cancer. This study was undertaken to identify transcription factors that regulate gene expression after androgen deprivation by castration (Cas). For the sake of comparison, we extended the analysis to the effects of administration of a high dose of 17β-estradiol (E2) and a combination of both (Cas+E2). We approached this by (i) identifying gene expression profiles and enrichment terms, and by searching for transcription factors in the derived regulatory pathways; and (ii) by determining the density of putative transcription factor binding sites in the proximal promoter of the 10 most up- or down-regulated genes in each experimental group in comparison to the controls Gapdh and Tbp7. Filtering and validation confirmed the expression and localized EVI1 (Mecom), NFY, ELK1, GATA2, MYBL1, MYBL2, and NFkB family members (NFkB1, NFkB2, REL, RELA and RELB) in the epithelial and/or stromal cells. These transcription factors represent major regulators of epithelial cell survival and immaturity as well as an adaptation of the gland as an immune barrier in the absence of functional stimulation by androgens. Elk1 was expressed in smooth muscle cells and was up-regulated after day 4. Evi1 and Nfy genes are expressed in both epithelium and stroma, but were apparently not affected by androgen deprivation.


PLOS ONE | 2014

Menthol Inhibits Detrusor Contractility Independently of TRPM8 Activation

Antonio Celso Saragossa Ramos-Filho; Ajay M. Shah; Taize M. Augusto; Guilherme Oliveira Barbosa; Luiz O. Leiria; Hernandes F. Carvalho; Edson Antunes; Andrew D. Grant

Agonists such as icilin and menthol can activate the cool temperature-sensitive ion channel TRPM8. However, biological responses to menthol may occur independently of TRPM8 activation. In the rodent urinary bladder, menthol facilitates the micturition reflex but inhibits muscarinic contractions of the detrusor smooth muscle. The site(s) of TRPM8 expression in the bladder are controversial. In this study we investigated the regulation of bladder contractility in vitro by menthol. Bladder strips from wild type and TRPM8 knockout male mice (25–30 g) were dissected free and mounted in organ baths. Isometric contractions to carbachol (1 nM–30 µM), CaCl2 (1 µM to 100 mM) and electrical field stimulation (EFS; 8, 16, 32 Hz) were measured. Strips from both groups contracted similarly in response to both carbachol and EFS. Menthol (300 µM) or nifedipine (1 µM) inhibited carbachol and EFS-induced contractions in both wild type and TRPM8 knockout bladder strips. Incubation with the sodium channel blocker tetrodotoxin (1 µM), replacement of extracellular sodium with the impermeant cation N-Methyl-D-Glucamine, incubation with a cocktail of potassium channel inhibitors (100 nM charybdotoxin, 1 µM apamin, 10 µM glibenclamide and 1 µM tetraethylammonium) or removal of the urothelium did not affect the inhibitory actions of menthol. Contraction to CaCl2 was markedly inhibited by either menthol or nifedipine. In cultured bladder smooth muscle cells, menthol or nifedipine abrogated the carbachol or KCl-induced increases in [Ca2+]i. Intravesical administration of menthol increased voiding frequency while decreasing peak voiding pressure. We conclude that menthol inhibits muscarinic bladder contractions through blockade of L-type calcium channels, independently of TRPM8 activation.


The Prostate | 2018

Macrophage roles in the clearance of apoptotic cells and control of inflammation in the prostate gland after castration

Juliete A.F. Silva; Alexandre Bruni-Cardoso; Taize M. Augusto; Danilo M. Damas-Souza; Guilherme Oliveira Barbosa; Sérgio Luis Felisbino; Dagmar Ruth Stach-Machado; Hernandes F. Carvalho

Androgen deprivation results in massive apoptosis in the prostate gland. Macrophages are actively engaged in phagocytosing epithelial cell corpses. However, it is unknown whether microtubule‐associated protein 1 light chain 3 alpha (LC3)‐associated phagocytosis (LAP) is involved and contribute to prevent inflammation.


Cell Biology International | 2017

Heparanase 1 involvement in prostate physiopathology

Guilherme Oliveira Barbosa; Nilva de Karla Cervigne; Hernandes F. Carvalho; Taize M. Augusto

The prostate is a compound exocrine gland of the male reproductive tract universally present in mammals. It is highly responsive to androgen and can be committed by a variety of pathological complications as prostatitis, benign, and malignant proliferative changes, which may be intensified by aging. Prostate intensively turnover its extracellular matrix (ECM) either at homeostasis or disease which includes a dynamically change of glycosaminoglycan composition during the life of an individual. Among the different enzymes playing a role in such changes, heparanase‐1 is responsible for cleaving heparan sulfate (HS) at a limited number of sites, clearly involved in tissue remodeling. Its activity has been strongly implicated in cell invasion associated with cancer metastasis, a consequence of the structural modification that loosens the ECM barrier. In the present review we focuses in some aspects of the prostate physiology and diseases, particular prostate cancer, evidencing how the HPSE‐1 activity encompasses the relationship of both processes.


Microscopy Research and Technique | 2016

Multimodal and non-linear optical microscopy applications in reproductive biology.

Javier Adur; Guilherme Oliveira Barbosa; V. B. Pelegati; Mariana Ozello Baratti; Carlos L. Cesar; V.H. Casco; Hernandes F. Carvalho

A plethora of optical techniques is currently available to obtain non‐destructive, contactless, real time information with subcellular spatial resolution to observe cell processes. Each technique has its own unique features for imaging and for obtaining certain biological information. However none of the available techniques can be of universal use. For a comprehensive investigation of biological specimens and events, one needs to use a combination of bioimaging methods, often at the same time. Some modern confocal/multiphoton microscopes provide simultaneous fluorescence, fluorescence lifetime imaging, and four‐dimensional imaging. Some of them can also easily be adapted for harmonic generation imaging, and to permit cell manipulation technique. In this work we present a multimodal optical workstation that extends a commercially available confocal microscope to include nonlinear/multiphoton microscopy and optical manipulation/stimulation tools. The nonlinear microscopy capabilities were added to the commercial confocal microscope by exploiting all the flexibility offered by the manufacturer. The various capabilities of this workstation as applied directly to reproductive biology are discussed. Microsc. Res. Tech. 79:567–582, 2016.


Cytotherapy | 2015

Combined dermatan sulfate and endothelial progenitor cell treatment: action on the initial inflammatory response after arterial injury in C57BL/6 mice

Juliana Aparecida Preto de Godoy; Giane Daniela Carneiro; Micheli Severo Sielski; Guilherme Oliveira Barbosa; Claudio C. Werneck; Cristina P. Vicente

BACKGROUND AIMS Dermatan sulfate (DS), an anticoagulant and antithrombotic glycosaminoglycan, also has anti-inflammatory activity. In this study, we investigated the effect of DS treatment in the presence or absence of bone marrow mononuclear cells (MNCs) or endothelial progenitor cells (EPCs) in the vascular response to carotid artery lesion in C57BL6 mice. METHODS Thrombus formation, the expression of adhesion molecules and factors involved in vascular remodeling, inflammation or vascular tone were analyzed by histologic examination, Western blotting and enzyme-linked immunoassay 1 and 3 days after vascular injury. RESULTS DS injections prevented thrombus formation and decreased P-selectin expression after 3 days of the injury. DS treatment also increased plasma SDF-1 levels but failed to rescue endothelial nitric oxide synthase (eNOS) expression, which is responsible for vascular tone. Treatment with MNCs alone failed to prevent thrombus formation 1 day after injury and increased intercellular adhesion molecule-1 expression, likely because of the inflammatory nature of these cells. Treatment with EPCs with DS was the most efficient among all therapies studied. Dual administration of EPCs and DS promoted an increase in the expression of adhesion molecules and, at the same time, induced a higher expression of eNOS at the injury site. Furthermore, it stimulated an elevated number of EPCs to migrate and adhere to the vascular wall. DISCUSSION Simultaneous treatment with EPCs and DS increased the expression of adhesion molecules, prevented thrombosis, rescued the expression of eNOS and increased migration of EPCs to the site of injury, thereby affecting thrombus remodeling and inflammation and can be involved in vessel hemostasis.


Tumor Biology | 2018

Collagen analysis by second-harmonic generation microscopy predicts outcome of luminal breast cancer

Rodrigo de Andrade Natal; José Vassallo; Geisilene R. Paiva; V. B. Pelegati; Guilherme Oliveira Barbosa; Guilherme Rossi Assis de Mendonça; Caroline Bondarik; Sophie Françoise Mauricette Derchain; Hernandes F. Carvalho; Carmen Silvia Passos Lima; Carlos L. Cesar; Luis Otávio Sarian

Second-harmonic generation microscopy represents an important tool to evaluate extracellular matrix collagen structure, which undergoes changes during cancer progression. Thus, it is potentially relevant to assess breast cancer development. We propose the use of second-harmonic generation images of tumor stroma selected on hematoxylin and eosin–stained slides to evaluate the prognostic value of collagen fibers analyses in peri and intratumoral areas in patients diagnosed with invasive ductal breast carcinoma. Quantitative analyses of collagen parameters were performed using ImageJ software. These parameters presented significantly higher values in peri than in intratumoral areas. Higher intratumoral collagen uniformity was associated with high pathological stages and with the presence of axillary lymph node metastasis. In patients with immunohistochemistry-based luminal subtype, higher intratumoral collagen uniformity and quantity were independently associated with poorer relapse-free and overall survival, respectively. A multivariate response recursive partitioning model determined 12.857 and 11.894 as the best cut-offs for intratumoral collagen quantity and uniformity, respectively. These values have shown high sensitivity and specificity to differentiate distinct outcomes. Values of intratumoral collagen quantity and uniformity exceeding the cut-offs were strongly associated with poorer relapse-free and overall survival. Our findings support a promising prognostic value of quantitative evaluation of intratumoral collagen by second-harmonic generation imaging mainly in the luminal subtype breast cancer.


Journal of Cellular Physiology | 2018

The role of SDF1 in prostate epithelial morphogenesis: BARBOSA et al.

Guilherme Oliveira Barbosa; Taize M. Augusto; Alexandre Bruni-Cardoso; Hernandes F. Carvalho

Androgens induce rat prostate induction from the urogenital sinus epithelium at embryonic day 17.5. Subsequent morphogenesis, including epithelial cord growth, branching, and canalization, results from concerted paracrine interactions with the stroma. A significant number of paracrine factors bind heparan sulfate (HS). We hypothesized that interfering with overall sulfation could disrupt the signaling mediated by HS‐binding factors and that the undersulfated environment would allow investigation of individual exogenous morphogens. First, we investigated whether acinar morphogenesis involved HS‐proteoglycan expression and found that syndecans 1 and 3 were upregulated in RWPE1 cells in the transition from two‐ to three‐dimensional (3D) Matrigel, capable of promoting spheroid formation. We then investigated whether sodium chlorate, a general sulfation inhibitor, interfered with spheroid formation by RWPE1 cells and acinar morphogenesis in ex vivo ventral prostate (VP) organ culture. As expected, treatment with sodium chlorate inhibited spheroid formation by RWPE1 cells in 3D culture. Chlorate also inhibited ex vivo VP epithelial branching and canalization, resulting in long branchless epithelial structures. We then investigated whether the HS‐binding factors, FGF10, TGFβ1, and SDF1, could reverse the effect of sodium chlorate. Although no effect was seen in the FGF10‐ and TGFβ1‐treated samples, SDF1 promoted epithelial canalization in the low sulfated environment, highlighting its specific role in lumen formation. Altogether, the results show that sodium chlorate perturbed prostate morphogenesis and allowed investigation of factors involved in branching and/or canalization, implicating SDF1 signaling in epithelial canalization.


Journal of Neuroinflammation | 2016

Impairment of toll-like receptors 2 and 4 leads to compensatory mechanisms after sciatic nerve axotomy

Camila Marques Freria; D. Bernardes; G. L. Almeida; Gustavo Ferreira Simões; Guilherme Oliveira Barbosa; Alexandre Leite Rodrigues de Oliveira

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Taize M. Augusto

State University of Campinas

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Carlos L. Cesar

State University of Campinas

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Rafaela Rosa-Ribeiro

State University of Campinas

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V. B. Pelegati

National Institute of Standards and Technology

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Umar Nishan

COMSATS Institute of Information Technology

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