Laboratório de Farmacogenômica
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Laboratório de Farmacogenômica
The Pharmacogenomics Laboratory aims to understand how variations in the expression of non-coding RNAs, mainly microRNAs, small non-coding protein RNAS, influence the therapeutic response to drugs (pharmacogenomics), and to identify microRNAs as markers of metabolic diseases to unravel possible pharmacological targets for the treatment of these diseases.
In our laboratory, we study the role of microRNAs in the pathophysiology of obesity and obesity-related diseases. Our main goal is to use microRNAs as drugs or drug targets in the treatment of obesity. We used preclinical models of obesity, diabetes and non-alcoholic fatty liver disease and in vitro models with cell culture. Our recent research has focused on microRNAs in extracellular vesicles in inter-organ communication in obesity. Below are listed the projects
Cells can communicate with neighboring or distant cells through exosomes, a type of extracellular vesicle that can carry microRNAs (miRNAs), small non-coding RNAs that regulate gene expression. Studies have shown the role of exosomes in different diseases, however little is known about their role in metabolic diseases. Obesity is an important risk factor for chronic diseases and represents a threat to global public health. Since the content and number of exosomes released are altered during obesity, we assume that intercellular communication via exosomes may play a role in the pathophysiology of obesity. The objective of this project is to evaluate the role of exosomal microRNAs in the communication between liver, skeletal muscle and white adipose tissue during obesity and their main metabolic implications.
Extracellular vesicles containing microRNAs can be released from skeletal muscle and deliver their microRNA content locally to skeletal muscle or distant tissues such as adipose tissue or liver and exert their post-transcriptional regulation action on these tissues, modulating the metabolism of that organ, one of the mechanisms proposed to explain the beneficial effects of physical exercise on these organs. However, there are no studies that show the origin of microRNAs contained in vesicles after a physical exercise session, nor is it known whether these microRNAs are capable of mimicking the beneficial effect of physical training. The present project has the following objectives: 1) to investigate which tissues are important sources of microRNAs in circulating extracellular vesicles after aerobic physical training; 2) to evaluate whether microRNAs in extracellular vesicles can mimic the beneficial effects of physical exercise in obese mices.
Obesity, defined as the chronic imbalance between energy consumption and expenditure, leading to a positive energy balance and, consequently, the accumulation of lipids in adipose tissue, is a multifactorial disease, influenced by genetic, environmental and behavioral factors. Despite these modifiable factors that influence obesity such as physical inactivity and a diet rich in fat and sugar, there are other non-modifiable risk factors, such as genetic factors or as indicated in animal studies, epigenetic mechanisms programmed in utero. Several studies have pointed out microRNAs, small non-coding RNAs, as important in the development of obesity, both acquired by maternal inheritance and induced by a high-fat diet. Also, studies made with humans and murines pointed out that therapeutic strategies, such as aerobic exercise, modulate microRNAs, circulating and in adipose tissue. Given the above, in this project we used the maternal inheritance model to study the participation of microRNAs in the development of obesity. Aerobic training will be used to understand the participation of microRNAs in strategies that improve obesity. It is expected that the results obtained will contribute to a better understanding of the molecular mechanisms that lead to obesity, and point to microRNAs as therapeutic targets for therapeutic interventions in obesity.
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From a therapeutic point of view, it is possible to carry out microRNA-based treatment using two strategies: 1) microRNA (s) replacement through miRNA mimetic agents (Figure A) and 2) microRNA (s) inhibition through microRNA inhibitors or antimiRs (Figure B). Overtime, both mimetics and antimiRs underwent chemical modifications to the nucleotide framework in order to resist degradation by RNAses present in serum and in cell compartments, the main challenge of RNA-based therapy. However, it is noteworthy that mimetics are more challenging, as the modifications can lead to alteration of the microRNA pharmacodynamics, which means loss of silencing capacity of the target mRNA. This loss of efficacy is related to the loading of miRNA in the silencing complex.
Thus, alternative methods have been developed to increase the effectiveness of miRNA delivery for in vivo treatment, such as the encapsulation of miRNA mimetics in nanoparticles or through viral vectors such as the adeno-associated virus. Many factors must be taken into account such as the best carrier, the best type of synthetic miRNA, target organ and form of administration and the risks of degradation of the molecule. Focusing on the development of microRNA-based therapies for the treatment of diseases associated with obesity such as insulin resistance and NAFLD and based on previous studies of our laboratory on microRNAs differentially expressed in these tissues, we have used microRNAs in vectors or contained in vesicles for the treatment of obese animals with diabetes and/or non-alcoholic fatty liver disease.
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Cushing’s syndrome (endogenous or iatrogenic) includes a set of diseases that are characterized by excessive exposure to glucocorticoids, with a consequent break in the circadian rhythm of the hypothalamic-pituitary-adrenal axis. From a clinical point of view, in humans, the scenario is one of redistribution of body fat with an increase in central adiposity and a reduction of it in limbs. In parallel, it can be observed a case of metabolic syndrome with its classic components: insulin resistance (which can lead to type 2 diabetes mellitus), dyslipidemia, greater susceptibility to systemic arterial hypertension, in addition to other signs and symptoms, including atrophy muscle, osteopenia, abdominal streaks and exacerbated protein catabolism. MicroRNAs can participate in the effect of glucocorticoids both in the functionality of adipose tissue and in its anti-inflammatory action. We use the iatrogenic Cushing model to understand the mechanisms involved in glucocorticoid-induced adipose tissue plasticity, and in this model we intend to investigate the participation of microRNAs in this process. A better understanding of how glucocorticoids work is important to comprehend their role in inducing the Cushing phenotype and how it works to promote the accumulation of visceral fat.
Hyperglycemia Chronicle disease is a primary triggering factor for diabetes complications, including cardiovascular disease, the leading cause of death in individuals with diabetes. Although hyperglycemia can be controlled through pharmacological therapies, physical exercise or changes in diet, several patients continue to suffer cardiovascular complications. This phenomenon was called metabolic memory, due to a supposed “memory” of the cells to high glucose exposure leading to the continuity of harmful effects to the organism even after normalization of blood glucose. However, a new class of antidiabetic drugs, glyphlozines, appeared to have had a cardioprotective effect in patients with diabetes. Our hypothesis is that glyphozins work by “erasing” the metabolic memory of cardiac cells. Among the molecular mechanisms proposed for the cause of the phenomenon of metabolic memory is the (de) regulation by microRNAs that occurs in diabetes. Therefore, it is possible that the cardioprotective effect of glyphozins is associated with the regulation of miRNA expression in the heart. In this project, we used the experimental model of obesity-induced diabetic cardiomyopathy and performed functional and histological analyzes to establish the condition. The improvement of the condition by glyphozins will be associated with the expression of microRNAs in the heart.
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Non-alcoholic fatty liver disease (NAFLD) comprises a spectrum of diseases ranging that goes from the presence of hepatic steatosis in the absence of excessive alcohol consumption to steatohepatitis, which may progress in the long term to fibrosis, cirrhosis and hepatocellular carcinoma. Knockout mice for the enzyme thimet oligopeptidase (EP24.15 or THOP -/-) show resistance to the induction of obesity and NAFLD by a high fat diet, and also present alteration expression of microRNAs previously associated with NAFLD. It has recently been shown that peptides processed by thimet oligopeptidase can prevent microRNA maturation. We hypothesize that the oligopeptidase deletion causes accumulation of peptides that direct or indirectly interact with microRNAs involved in the physiopathology of NAFLD and protect the animal from developing steatohepatitis.
Laboratório de Farmacogenômica
Universidade de São Paulo
Instituto de Ciências Biomédicas
Departamento de Farmacologia
