Leonardo dos Reis Silveira
Laboratory of Muscle Molecular Metabolism (Instagram: @mmblab_prof.leonardo)
This laboratory studies broad aspects of molecular processes that regulates mitochondrial bioenergetics and its biogenesis process in peripheral tissues of mammals with focus on new targets capable of enhancing mitochondrial function and consequently reversing metabolic dysfunction.
TEAM
RESEARCH FELLOW
- Carolina Martins lazaro
- Lucas Saavedra
PHD
- Priscila Romano Raimundo
- Michelle Gomes
Master
- Victória Soran
SCIENTIFIC INITIATION
- Letícia Basso Gomes
- Taciany Simões
MAIN FINDINGS
1. Mitochondria are organelles known primarily for generating ATP. For instance, cold and exercise are two well-known conditions to induce mitochondrial function and biogenesis in skeletal muscle, which ultimately depends on upregulation of mitochondrial genetic program. The transcription process is finely regulated by transcription factors, nuclear receptors and co-regulators. Among the best-known coregulators is the corepressor, NCoR1. Recently we identified new interactors of NcoR1 with potential to regulate its activity. The PABPC4 protein was identified, whose best-known function is the interaction with the poly(A) tail of mRNA. Interestingly, upon different conditions known to induce mitochondrial function and biogenesis, both mRNA expression and PABPC4 protein content were markedly reduced. Of noting, the cells with PABPC4 silencing when subjected to energetic stress were also demonstrated to exhibit higher oxygen consumption when compared to the control cells and lower repression of PPAR. Mechanistically, we demonstrated that PABPC4 silencing increased the ubiquitination and degradation of NCoR1, leading to a lower transcriptional repression of PPAR-regulated genes. As a consequence, cells with PABPC4 silencing had a greater capacity to metabolize lipids, reduced intracellular lipid droplets and cell death. A lower expression of PABPC4 may be an adaptive event required to induce mitochondrial activity in response to metabolic stress in skeletal muscle cells. As such, the NcoR1-PABPC4 interface might be a new road to the treatment of metabolic diseases.
2. The adjustment between metabolic demand and the supply of energy substrates is made possible by the regulation of mitochondrial function at both post-translational and transcriptional levels. The family of nuclear receptors is essential for translating environmental signals into transcriptional modulation, which is orchestrated by the antagonistic action of co-repressors and co-activators. Using publicly available ChIP-seq data, we demonstrate that the Nr2f6 orphan nuclear receptor cistrome is enriched in oxidative metabolism pathway genes. Our global transcriptome profile of Nr2f6-depleted myocytes surprisingly revealed that these cells have an increased myogenic potential and subsequent experiments demonstrated an increased lipid oxidation capacity and lower lactate production, with concomitant activation of the AMPK and Akt pathways. Transactivation assays of the uncoupling protein 3 promoter point to direct repression by Nr2f6 and considering that there is also an increase in UCP3 expression after knockdown of Nr2f6, the metabolic phenotypes can be partially explained by this phenomenon. Experiments that seek to validate direct targets of Nr2f6 and the translational potential of our findings are ongoing, however we can conclude that Nr2f6 acts as a molecular transducer that plays a crucial role in maintaining the balance between skeletal muscle contractile function and oxidative capacity. These results have significant implications for the development of potential therapeutic strategies for metabolic diseases and myopathies.
3. We showed that the transcriptional coregulators PGC-1α and NCoR1 are essential mediators of mitochondrial redox homeostasis. PGC-1α and NCoR1 act as activator and repressor of Sod2 expression, respectively. This mechanism is essential for the cellular antioxidant capacity and viability during metabolic stress.
4. In 2020, we published a study in Am. J. Physiol. showing the role of PPAR in the regulation of miR-let-7b, an important regulator of Akt in mouse and human skeletal muscle tissue. This study was developed in partnership with Dr. Narkar VA, from the University of Texas Health Science Center at Houston (UTHealth Houston), Houston, USA.
5. Impaired mitochondrial function and altered expression in metabolic genes are correlated with various metabolic diseases such as obesity and diabetes. We now identify a microRNA that regulates PGC1α expression through a SNARK dependent mechanism. We discovered that under metabolic stressful conditions, SNARK increases miR-696 expression, which in turn reduces the expression of PGC1α, one of the major regulators of mitochondrial biogenesis and function. Our findings show that the microRNA miR-696 expression is markedly induced in skeletal muscle of obese and diabetic mice, whereas Pgc1α is expressed at a lower level being inversely correlated with miR-696 expression as indicated by analysis of either white (tibialis anterior or extensor digitorum longus) or red (soleus) muscle fibers. We showed the negative effect of miR-696 in the mitochondrial function of C2C12 cells under palmitate exposure. Moreover, glucose uptake was impaired in C2C12 cells transfected with miR-696 mimetic. To determine the mechanism behind the regulation of miR-696 expression, we evaluated the miR-696 expression in skeletal muscle from several lines of transgenic mice including AMPKα2 dominant-negative; SNARK dominant-negative and; wild-type SNARK. We observed that SNARK had a clear role in mediating a signal to induce miR-696 expression and to change mitochondrial respiration. These findings, which encompass muscle-specific transgenic animals as well as in vitro experiments, clearly demonstrate a novel axis, SNARK/miR-696/Pgc1α, where these players regulate mitochondrial function during stressful situations such as diabetes and obesity.Given that mitochondrial function plays a crucial role in cell homeostasis and its importance for cell survival in several diseases and conditions such as diabetes and obesity, our findings rise the importance of studying the new role of SNARK and the microRNA miR-696 as potential targets for metabolic therapies.
Mol Metab. 2021 Sep:51:101226. doi: 10.1016/j.molmet.2021.101226.
MAIN ARTICLES
- Dimitrius Santiago P. S. F. Guimarães et al. Concerted regulation of skeletal muscle metabolismand contractile properties by the orphan nuclearreceptor Nr2f6. Journal of Cachexia, Sarcopenia and Muscle, Março 2024. DOI: 10.1002/jcsm.13480. Impact factor 12.5.
- A. G. Oliveira, L.D. Oliveira, M.V. Cruz, D.S.P.S.F. Guimarães, T.I. Lima, B.C. Santos-Fávero, A.D. Luchessi, B.A. Pauletti, A.P. Leme, M.C. Bajgelman, J. Afonso, L.C.A. Regitano, H.F. Carvalho, E.M. Carneiro, J. Kobarg, V. Perissi, J. Auwerx, L.R. Silveira. Interaction between poly(A)-binding protein PABPC4 and nuclear receptor corepressor NCoR1 modulates a metabolic stress response. J Biol Chem.; 299(6):104702, 2023. doi: 10.1016/j.jbc.2023.104702. Fator de impacto: 5.48.
- Tanes Lima, Pirkka-Pekka Laurila, Martin Wohlwend, Jean David Morel, Ludger, Goeminne, Hao Li, Mario Romani, Li Xiaoxu, Chang-Myung Oh, Julijana Ivanisevic, Hector Gallart-Ayala, Barbara Crisol, Sabrina Pinchon, Florence Berlot, Leonardo R. Silveira, Suresh Jain, Johan Auwerx. Ceramide de novo Synthesis Inhibition Restores Mitochondrial and Protein Homeostasis in Muscle Aging. Science Translacional Medicine, 17;15(696), 2023. Fator Impacto: 19,34.
- André L. Queiroz, Hygor N. Araujo, Dawit A. Gonçalves1, Kawai So, Hirokazu Takahashi, Enilza M. Espreafico, Michael F. Hirshman, Luciane C. Alberici, Isis do Carmo Kettelhut, Laurie J. Goodyear and Leonardo R. Silveira. MicroRNA miR-696 is regulated by SNARK and induces mitochondrial dysfunction in mouse skeletal muscle through Pgc1α inhibition. Mol Metab, 31;51:101226, 2021.doi: 10.1016/j.molmet.2021.101226. Fator de impacto: 8.56.
- Tanes Lima, Leonardo R. Silveira. Opposing action of NCoR1 and PGC-1α in mitochondrial redox homeostasis. Free Radical in Biology and Medicine, 2019. doi: 10.1016/j.freeradbiomed.2019.08.006. Fator Impacto: 5,65.
- Teodoro, BG; Sampaio, IH; Bomfim LHM; Queiroz, AL; Carneiro, EM; Alberici; Cipolla-Neto, J; Amaral, FG; Lima TI, Uyemura SA; Silveira, LR. Melatonin prevents mitochondrial dysfunction and insulin resistance in rat skeletal muscle. Journal Pineal Research, 57(2):155-67, 2014. Fator Impacto: 12,081.
- Hygor N. Araujo; Tanes I. Lima1; Dimitrius Santiago P.S.F. Guimarães; Andre G. Oliveira1; Murilo V. Geraldo; Everardo M Carneiro; Alice C. Rodrigues, Vihang A. Narkar; Leonardo R. Silveira. Regulation of Lin28a-miRNA let-7b-5p pathway in the skeletal muscle cells by 2 PPARδ. Am J. Physiol – Cell Physiol. jul 2020. Fator Impacto: 4,40. doi: 10.1152/ajpcell.00233.2020.
Centro de Pesquisa em Obesidade e Comorbidades - 2º Andar
Instituto de Biologia - Bloco Z
Rua Carl Von Linaeus - s/n - Cidade Universitária
Campinas - SP, 13083-864
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E-mail: [email protected]
Linkedin: https://www.linkedin.com/in/leonardo-silveira-47229634/