Joyce Guerra

Dr. Joyce Guerra

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Research Focus & Metrics

Academic Career Length

11Years (2016-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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30 May 2019 in Scientific Reports
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MCMayara Medeiros de Freitas Carvalho
Mayara Medeiros de Freitas Carvalho
NLNara Nunes Lage
Nara Nunes Lage
APAlice Helena de Souza Paulino
Alice Helena de Souza Paulino
RPRenata Rebeca Pereira
Renata Rebeca Pereira
LALetícia Trindade de Almeida
Letícia Trindade de Almeida
JGJoyce Guerra
Joyce Guerra
Non-alcoholic fatty liver disease (NAFLD), the most predominant liver disease worldwide, is a progressive condition that encompasses a spectrum of disorders ranging from steatosis to steatohepatitis, and, ultimately, cirrhosis and hepatocellular carcinoma. Although the underlying mechanism is complex and multifactorial, several intracellular events leading to its progression have been identified, including oxidative stress, inflammation, mitochondrial dysfunction, apoptosis, and altered endoplasmic reticulum (ER) homeostasis. Phenolic compounds, such as those present in açai (Euterpe oleracea Mart.), are considered promising therapeutic agents due to their possible beneficial effects on the prevention and treatment of NAFLD. We tested in vitro effects of aqueous açai extract (AAE) in HepG2 cells and its influence on oxidative stress, endoplasmic reticulum stress, and inflammation in a murine model of high fat diet-induced NAFLD. In vitro AAE exhibited high antioxidant capacity, high potential to inhibit reactive oxygen species production, and no cytotoxicity. In vivo, AAE administration (3 g/kg) for six weeks attenuated liver damage (alanine aminotransferase levels), inflammatory process (number of inflammatory cells and serum TNFα), and oxidative stress, through the reduction of lipid peroxidation and carbonylation of proteins determined by OxyBlot and modulation of the antioxidant enzymes: glutathione reductase, SOD and catalase. No change was observed in collagen content indicating an absence of fibrosis, stress-related genes in RE, and protein expression of caspase-3, a marker of apoptosis. With these results, we provide evidence that açai exhibits hepatoprotective effects and may prevent the progression of liver damage related to NAFLD by targeting pathways involved in its progression.

1 January 2016 in Oxidative Medicine and Cellular Longevity
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RPRenata Rebeca Pereira
Renata Rebeca Pereira
IAIsabel Cristina Mallosto Emerich de Abreu
Isabel Cristina Mallosto Emerich de Abreu
JGJoyce Guerra
Joyce Guerra
NLNara Nunes Lage
Nara Nunes Lage
JLJuliana Márcia Macedo Lopes
Juliana Márcia Macedo Lopes
MPMaria Lucia Pedrosa
Maria Lucia Pedrosa
Açai (Euterpe oleracea Mart.), a fruit from the Amazon region, has emerged as a promising source of polyphenols. Açai consumption has been increasing owing to ascribed health benefits and antioxidant properties; however, its effects on hepatic injury are limited. In this study, we evaluated the antioxidant effect of filtered açai pulp on the expression of paraoxonase (PON) isoforms and PON1 activity in rats with nonalcoholic fatty liver disease (NAFLD). The rats were fed a standard AIN‐93M (control) diet or a high‐fat (HF) diet containing 25% soy oil and 1% cholesterol with or without açai pulp (2 g/day) for 6 weeks. Our results show that açai pulp prevented low‐density lipoprotein (LDL) oxidation, increased serum and hepatic PON1 activity, and upregulated the expression of PON1 and ApoA‐I in the liver. In HF diet‐fed rats, treatment with açai pulp attenuated liver damage, reducing fat infiltration and triglyceride (TG) content. In rats receiving açai, increased serum PON1 activity was correlated with a reduction in hepatic steatosis and hepatic injury. These findings suggest the use of açai as a potential therapy for liver injuries, supporting the idea that dietary antioxidants are a promising approach to enhance the defensive systems against oxidative stress.

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VAVinícius Marques Arruda
Vinícius Marques Arruda
GAGabriela Tolentino Azevedo
Gabriela Tolentino Azevedo
MGMaria Julia Maia Gonçalves Granato
Maria Julia Maia Gonçalves Granato
AMAndré Carlos Pereira Matos
André Carlos Pereira Matos
TAThaise Gonçalves Araújo
Thaise Gonçalves Araújo
JGJoyce Guerra
Joyce Guerra
Non-alcoholic fatty liver disease (NAFLD) is a rising global burden, affecting one in four adults. Despite the increasing prevalence of NAFLD, the exact cellular and molecular mechanisms remain unclear, and effective therapeutic strategies are still limited. In vitro models of NAFLD are critical to understanding the pathogenesis and searching for effective therapies; thus, we evaluated the effects of free fatty acids (FFAs) on NAFLD hallmarks and their association with the modulation of Annexin A2 (ANXA2) and Keratin 17 (KRT17) in HepG2 cells. Our results show that oleic and palmitic acids can differentially induce intracellular lipid accumulation, cell death, and promote oxidative stress by increasing lipid peroxidation, protein carbonylation, and antioxidant defense depletion. Moreover, a markedly increased expression of inflammatory cytokines demonstrated the activation of inflammation pathways associated with lipotoxicity and oxidative stress. ANXA2 overexpression and KRT17 nuclear translocation were also observed, supporting the role of both molecules in the progression of liver disease. Taken together, these data provide insights into the interplay between ANXA2 and KRT17 in NAFLD, paving the way for understanding molecular mechanisms involved with the disease and developing new therapeutic strategies.

20 January 2022 in BMC Complementary Medicine and Therapies
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DBDouglas C. Brandão
Douglas C. Brandão
PLPaula M. A. P. Lima
Paula M. A. P. Lima
IMIsabella C. Martins
Isabella C. Martins
CCCarina S. Cordeiro
Carina S. Cordeiro
ACAntonielle O. Cordeiro
Antonielle O. Cordeiro
TAThaise Gonçalves Araújo
Thaise Gonçalves Araújo
Background: Breast Cancer (BC) is the most common cancer in women worldwide and, although 70% of patients are responsive to selective Estrogen Receptor (ER) modulators such as Tamoxifen (Tam), patients’ survival is comprised by resistance to endocrine therapy. Brazilian flora, especially the Amazon biome, is one of the richest global sources of native species with potentially bioactive compounds. Arrabidaea chica is a plant native to the Amazon that has been used in the treatment of different diseases. However, its action on BC remains unclear. Methods: Herein the biological effects of the chloroform extract of A. chica (CEAC) were evaluated on BC cells and in in vivo model. After confirmation of CEAC antioxidant capacity, cells were treated with CEAC and Tam, alone and with CEAC+Tam. The cell viability was evaluated by MTT and hormone receptor transcripts levels were assessed (ESR1, ESR2 and AR). Finally, anticarcinogenicity of CEAC was recorded in Drosophila melanogaster through Epithelial Tumor Test (ETT). Results: The study confirmed the antioxidant activity of CEAC. CEAC was selective for MCF-7, downregulating ESR2 and AR transcripts and upregulating ESR2 expression. The modulatory effects of CEAC on ERs did not differ between cells treated with Tam and with CEAC+Tam. Interestingly, previous treatment with CEAC, followed by treatment with Tam promoted a significant decrease in cell viability. The extract also presented anticarcinogenic effect in in vivo assay. Conclusion: The bioassays on breast tumor cells demonstrated the antiproliferative activity of the extract, which modulated the expression of hormone receptors and sensitized luminal tumor cells to Tam. These results suggest that CEAC could be a complementary treatment for BC.

1 January 2018 in Archivos Latinoamericanos de Nutrición
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NLNara Nunes Lage
Nara Nunes Lage
JLJuliana Márcia Macedo Lopes
Juliana Márcia Macedo Lopes
RPRenata Rebeca Pereira
Renata Rebeca Pereira
JGJoyce Guerra
Joyce Guerra
MPMariana de Fátima Albuquerque Pereira
Mariana de Fátima Albuquerque Pereira
MPMaria Lúcia Pedrosa
Maria Lúcia Pedrosa
Buriti pulp flour (BPF) contains significant levels of antioxidants. This study evaluated the effect of BPF on biomarkers of oxidative damage in the liver, heart, and pancreas of diabetic rats. The chemical composition, antioxidant capacity, and polyphenol content of BPF were determined. Thirty-six female Fisher rats were divided into four groups: control (C); control + BPF (CB); diabetic (D); diabetic + BPF (DB). Diabetes was induced by treatment with streptozotocin. Thirty days after the induction of diabetes, glucose, total cholesterol and triacylglycerides serum levels, aminotransferase and paraoxonase activities were evaluated. Oxidative damage to lipids and proteins was assessed through thiobarbituric acid reactive substances (TBARS) and protein carbonyl analyses, respectively. Histopathological analyses were also performed. BPF contained high concentrations of phenolic compounds, lipids, and fibers, and exhibited a high capacity to neutralize the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. Diabetes was evidenced by equivalent high levels of glucose in plasma from rats in the D and DB groups. Diabetic rats in both groups also presented the same increased activity of aminotransferases. Protein carbonyl levels were increased in liver, heart, and pancreas in the D compared with C group. Although treatment with BPF did not result in any histopathological alterations, it reduced significantly the levels of TBARS in the heart and protein carbonyls in the liver and heart. No effect on blood glucose and tissue histology was observed following treatment with BPF. However, BPF diminished oxidative damage in liver and heart, indicating a possible antioxidant potential in vivo, in addition to in vitro.

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DBDayanne Silva Borges
Dayanne Silva Borges
LVLara Vecchi
Lara Vecchi
DBDeysse Carla Tolentino Barros
Deysse Carla Tolentino Barros
VAVinícius Marques Arruda
Vinícius Marques Arruda
HFHelen Soares Valença Ferreira
Helen Soares Valença Ferreira
TAThaise Gonçalves Araújo
Thaise Gonçalves Araújo
Glyphosate (GLY) was developed in the early 1970s and has become the most used broad-spectrum herbicide in the world so far. Its main metabolite is aminomethylphosphonic acid (AMPA), and the accumulation of GLY and its derivative compounds raises some concerns regarding possible health outcomes. In this study, we aimed to evaluate the effects of GLY and AMPA on prostate cell lines by evaluating cell viability, proliferation, gene and protein expression, and cellular pathways involved in the response to oxidative stress. Our results indicated that GLY and AMPA reduced the cell viability of tumorigenic and non-tumorigenic prostate cell lines only at higher concentrations (10 mM GLY and 20 mM AMPA). In contrast, both compounds increased the clonogenicity of non-tumorigenic PNT2 cells, mainly at concentrations below the IC50 (5 mM GLY and 10 mM AMPA). Moreover, treatment of non-tumorigenic cells with low concentrations of GLY or AMPA for 48 h increased GSTM3 expression at both mRNA and protein levels. In contrast, the treatments decrease the GST activity and induced an increase in oxidative stress, mainly at lower concentrations. Therefore, both compounds can cause cellular damage even at lower concentrations in non-tumorigenic PNT2 cells, mainly affecting cell proliferation and oxidative stress.