Involvement of Alternative Splicing Regulation in Adipose Tissue Thermogenic Induction

[eng] Alternative splicing (AS) is a gene expression regulatory mechanism that enables generation of multiple mRNA isoforms from a single gene which commonly are translated into proteins. This mechanism is tightly regulated by cis- and trans-acting factors. Among the latter, there are splicing facto...

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Autor: Castellá Giner, Moisés
Tipo de recurso: tesis doctoral
Estado:Versión publicada
Fecha de publicación:2023
País:España
Institución:Universidad de Barcelona
Repositorio:Dipòsit Digital de la UB
OAI Identifier:oai:diposit.ub.edu:2445/202765
Acceso en línea:https://hdl.handle.net/2445/202765
http://hdl.handle.net/10803/689129
Access Level:acceso abierto
Palabra clave:Teixit adipós
Expressió gènica
Micro RNAs
Metabolisme dels lípids
Gene expression
MicroRNAs
Lipid metabolism
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oai_identifier_str oai:diposit.ub.edu:2445/202765
network_acronym_str ES
network_name_str España
repository_id_str
dc.title.none.fl_str_mv Involvement of Alternative Splicing Regulation in Adipose Tissue Thermogenic Induction
title Involvement of Alternative Splicing Regulation in Adipose Tissue Thermogenic Induction
spellingShingle Involvement of Alternative Splicing Regulation in Adipose Tissue Thermogenic Induction
Castellá Giner, Moisés
Teixit adipós
Expressió gènica
Micro RNAs
Metabolisme dels lípids
Gene expression
MicroRNAs
Lipid metabolism
title_short Involvement of Alternative Splicing Regulation in Adipose Tissue Thermogenic Induction
title_full Involvement of Alternative Splicing Regulation in Adipose Tissue Thermogenic Induction
title_fullStr Involvement of Alternative Splicing Regulation in Adipose Tissue Thermogenic Induction
title_full_unstemmed Involvement of Alternative Splicing Regulation in Adipose Tissue Thermogenic Induction
title_sort Involvement of Alternative Splicing Regulation in Adipose Tissue Thermogenic Induction
dc.creator.none.fl_str_mv Castellá Giner, Moisés
author Castellá Giner, Moisés
author_facet Castellá Giner, Moisés
author_role author
dc.contributor.none.fl_str_mv Villarroya i Gombau, Francesc
Cereijo Téllez, Rubén
Universitat de Barcelona. Departament de Bioquímica i Biomedicina Molecular
Adipose tissues
dc.subject.none.fl_str_mv Teixit adipós
Expressió gènica
Micro RNAs
Metabolisme dels lípids
Gene expression
MicroRNAs
Lipid metabolism
topic Teixit adipós
Expressió gènica
Micro RNAs
Metabolisme dels lípids
Gene expression
MicroRNAs
Lipid metabolism
description [eng] Alternative splicing (AS) is a gene expression regulatory mechanism that enables generation of multiple mRNA isoforms from a single gene which commonly are translated into proteins. This mechanism is tightly regulated by cis- and trans-acting factors. Among the latter, there are splicing factors, which form part of spliceosome, and splicing regulators, which can enhance or inhibit spliceosome activity. Therefore, AS is a mechanism that can have a dramatic impact in the regulation of protein activity, which can affect other relevant cellular mechanisms and even tissue functions. AS has been studied extensively in some diseases but the knowledge in adipometabolic pathology is still scarce but growing evidence highlights AS as a regulator of gene expression in adipose tissue. Besides energy-storing white adipose tissue, AS is especially unexplored in brown adipose tissue (BAT), which can dissipate energy in form of heat and thus increase energy expenditure. Considering the potential therapeutic approach of using rediscovered BAT in human adults to assist in the treatment of obesity due to its special energy-consuming properties, we decided to study the possible involvement of AS in brown/beige adipose tissue thermogenic function. We first determined the transcriptomic signature associated with the acquisition of a beige phenotype in human adipose tissue by analysing adipose browning occurring in patients affected by pheochromocytoma using deep RNAseq analysis and last generation bioinformatic tools. We identified a massive down regulation of splicing machinery- associated genes occurring in association with human adipose browning and in differentiating human beige cells in culture. In addition, these splicing modifications may act by means of direct modulation of the enzymatic machinery involved in key metabolic and thermogenic functions and/or more indirectly affecting the isoform expression of master regulators and functional molecular actors of browning. This affectation of splicing machinery-associated genes in adipose browning led us to investigate the possible role of two candidates: SF3B1, a key component of the spliceosome, and RBFOX2, a splicing factor/regulator of AS, in brown adipocytes. We discovered that SF3B1 was up-regulated in vivo in murine BAT after thermogenic activation in response to acute cold, and in in vitro brown adipocytes in response to cAMP treatment, the main intracellular mediator of the noradrenergic stimuli. We further explored the effects of blocking SF3B1 using siRNA-mediated interference and a pharmacological inhibitor, pladienolide-B. Blockage of this splicing factor actions reduced both the expression of prominent thermogenesis-associated transcripts and respiration in brown adipocytes in vitro. Next, we assessed the effects of silencing RBFOX2 in brown adipocytes in vitro through shRNA-mediated interference. Repression of RBFOX2 caused alterations in transcript levels of thermogenesis-related genes and in alternative splicing-driven mRNA isoforms involved in brown adipocyte function. Moreover, signs of impaired respiration and lipolysis, together with the aforementioned changes, suggested that RBFOX2 activity is required for appropriate brown adipocyte thermogenic function. Finally, we obtained preliminary results of adipose tissue-specific knock out of RBFOX2 in mice model which indicated mild effects on thermogenesis, with RBFOX2-KO mice showing enhanced cold exposure adaptation by increasing their body temperature faster that controls, but further research is required to full-characterize the role of RBFOX2 in vivo during adaptative thermogenesis. Taken together, our results indicate that AS is a critical process in brown adipose tissue functions that can have a deep impact in systemic energy homeostasis, suggesting further studies on the potential applications energy-consuming brown fat AS regulation- based therapies to counter obesity, type 2 diabetes and its associated comorbidties.
publishDate 2023
dc.date.none.fl_str_mv 2023
dc.type.none.fl_str_mv info:eu-repo/semantics/doctoralThesis
info:eu-repo/semantics/publishedVersion
format doctoralThesis
status_str publishedVersion
dc.identifier.none.fl_str_mv https://hdl.handle.net/2445/202765
http://hdl.handle.net/10803/689129
url https://hdl.handle.net/2445/202765
http://hdl.handle.net/10803/689129
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.rights.none.fl_str_mv cc by-nc (c) Castellá Giner, Moisés, 2023
http://creativecommons.org/licenses/by-nc/3.0/es/
info:eu-repo/semantics/openAccess
rights_invalid_str_mv cc by-nc (c) Castellá Giner, Moisés, 2023
http://creativecommons.org/licenses/by-nc/3.0/es/
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Universitat de Barcelona
publisher.none.fl_str_mv Universitat de Barcelona
dc.source.none.fl_str_mv Tesis Doctorals - Departament - Bioquímica i Biomedicina Molecular
reponame:Dipòsit Digital de la UB
instname:Universidad de Barcelona
instname_str Universidad de Barcelona
reponame_str Dipòsit Digital de la UB
collection Dipòsit Digital de la UB
repository.name.fl_str_mv
repository.mail.fl_str_mv
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spelling Involvement of Alternative Splicing Regulation in Adipose Tissue Thermogenic InductionCastellá Giner, MoisésTeixit adipósExpressió gènicaMicro RNAsMetabolisme dels lípidsGene expressionMicroRNAsLipid metabolism[eng] Alternative splicing (AS) is a gene expression regulatory mechanism that enables generation of multiple mRNA isoforms from a single gene which commonly are translated into proteins. This mechanism is tightly regulated by cis- and trans-acting factors. Among the latter, there are splicing factors, which form part of spliceosome, and splicing regulators, which can enhance or inhibit spliceosome activity. Therefore, AS is a mechanism that can have a dramatic impact in the regulation of protein activity, which can affect other relevant cellular mechanisms and even tissue functions. AS has been studied extensively in some diseases but the knowledge in adipometabolic pathology is still scarce but growing evidence highlights AS as a regulator of gene expression in adipose tissue. Besides energy-storing white adipose tissue, AS is especially unexplored in brown adipose tissue (BAT), which can dissipate energy in form of heat and thus increase energy expenditure. Considering the potential therapeutic approach of using rediscovered BAT in human adults to assist in the treatment of obesity due to its special energy-consuming properties, we decided to study the possible involvement of AS in brown/beige adipose tissue thermogenic function. We first determined the transcriptomic signature associated with the acquisition of a beige phenotype in human adipose tissue by analysing adipose browning occurring in patients affected by pheochromocytoma using deep RNAseq analysis and last generation bioinformatic tools. We identified a massive down regulation of splicing machinery- associated genes occurring in association with human adipose browning and in differentiating human beige cells in culture. In addition, these splicing modifications may act by means of direct modulation of the enzymatic machinery involved in key metabolic and thermogenic functions and/or more indirectly affecting the isoform expression of master regulators and functional molecular actors of browning. This affectation of splicing machinery-associated genes in adipose browning led us to investigate the possible role of two candidates: SF3B1, a key component of the spliceosome, and RBFOX2, a splicing factor/regulator of AS, in brown adipocytes. We discovered that SF3B1 was up-regulated in vivo in murine BAT after thermogenic activation in response to acute cold, and in in vitro brown adipocytes in response to cAMP treatment, the main intracellular mediator of the noradrenergic stimuli. We further explored the effects of blocking SF3B1 using siRNA-mediated interference and a pharmacological inhibitor, pladienolide-B. Blockage of this splicing factor actions reduced both the expression of prominent thermogenesis-associated transcripts and respiration in brown adipocytes in vitro. Next, we assessed the effects of silencing RBFOX2 in brown adipocytes in vitro through shRNA-mediated interference. Repression of RBFOX2 caused alterations in transcript levels of thermogenesis-related genes and in alternative splicing-driven mRNA isoforms involved in brown adipocyte function. Moreover, signs of impaired respiration and lipolysis, together with the aforementioned changes, suggested that RBFOX2 activity is required for appropriate brown adipocyte thermogenic function. Finally, we obtained preliminary results of adipose tissue-specific knock out of RBFOX2 in mice model which indicated mild effects on thermogenesis, with RBFOX2-KO mice showing enhanced cold exposure adaptation by increasing their body temperature faster that controls, but further research is required to full-characterize the role of RBFOX2 in vivo during adaptative thermogenesis. Taken together, our results indicate that AS is a critical process in brown adipose tissue functions that can have a deep impact in systemic energy homeostasis, suggesting further studies on the potential applications energy-consuming brown fat AS regulation- based therapies to counter obesity, type 2 diabetes and its associated comorbidties.Universitat de BarcelonaVillarroya i Gombau, FrancescCereijo Téllez, RubénUniversitat de Barcelona. Departament de Bioquímica i Biomedicina MolecularAdipose tissues2023info:eu-repo/semantics/doctoralThesisinfo:eu-repo/semantics/publishedVersionapplication/pdfhttps://hdl.handle.net/2445/202765http://hdl.handle.net/10803/689129Tesis Doctorals - Departament - Bioquímica i Biomedicina Molecularreponame:Dipòsit Digital de la UBinstname:Universidad de BarcelonaIngléscc by-nc (c) Castellá Giner, Moisés, 2023http://creativecommons.org/licenses/by-nc/3.0/es/info:eu-repo/semantics/openAccessoai:diposit.ub.edu:2445/2027652026-05-27T06:46:51Z
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