Pub Date : 2024-05-03DOI: 10.1016/j.molmet.2024.101955
Cecile Jacovetti , Chris Donnelly , Véronique Menoud , Mara Suleiman , Cristina Cosentino , Jonathan Sobel , Kejing Wu , Karim Bouzakri , Piero Marchetti , Claudiane Guay , Bengt Kayser , Romano Regazzi
Objective
The contribution of the mitochondrial electron transfer system to insulin secretion involves more than just energy provision. We identified a small RNA fragment (mt-tRF-LeuTAA) derived from the cleavage of a mitochondrially-encoded tRNA that is conserved between mice and humans. The role of mitochondrially-encoded tRNA-derived fragments remains unknown. This study aimed to characterize the impact of mt-tRF-LeuTAA, on mitochondrial metabolism and pancreatic islet functions.
Methods
We used antisense oligonucleotides to reduce mt-tRF-LeuTAA levels in primary rat and human islet cells, as well as in insulin-secreting cell lines. We performed a joint transcriptome and proteome analysis upon mt-tRF-LeuTAA inhibition. Additionally, we employed pull-down assays followed by mass spectrometry to identify direct interactors of the fragment. Finally, we characterized the impact of mt-tRF-LeuTAA silencing on the coupling between mitochondrial metabolism and insulin secretion using high-resolution respirometry and insulin secretion assays.
Results
Our study unveils a modulation of mt-tRF-LeuTAA levels in pancreatic islets in different Type 2 diabetes models and in response to changes in nutritional status. The level of the fragment is finely tuned by the mechanistic target of rapamycin complex 1. Located within mitochondria, mt-tRF-LeuTAA interacts with core subunits and assembly factors of respiratory complexes of the electron transfer system. Silencing of mt-tRF-LeuTAA in islet cells limits the inner mitochondrial membrane potential and impairs mitochondrial oxidative phosphorylation, predominantly by affecting the Succinate (via Complex II)-linked electron transfer pathway. Lowering mt-tRF-LeuTAA impairs insulin secretion of rat and human pancreatic β-cells.
Conclusions
Our findings indicate that mt-tRF-LeuTAA interacts with electron transfer system complexes and is a pivotal regulator of mitochondrial oxidative phosphorylation and its coupling to insulin secretion.
{"title":"The mitochondrial tRNA-derived fragment, mt-tRF-LeuTAA, couples mitochondrial metabolism to insulin secretion","authors":"Cecile Jacovetti , Chris Donnelly , Véronique Menoud , Mara Suleiman , Cristina Cosentino , Jonathan Sobel , Kejing Wu , Karim Bouzakri , Piero Marchetti , Claudiane Guay , Bengt Kayser , Romano Regazzi","doi":"10.1016/j.molmet.2024.101955","DOIUrl":"10.1016/j.molmet.2024.101955","url":null,"abstract":"<div><h3>Objective</h3><p>The contribution of the mitochondrial electron transfer system to insulin secretion involves more than just energy provision. We identified a small RNA fragment (mt-tRF-Leu<sup>TAA</sup>) derived from the cleavage of a mitochondrially-encoded tRNA that is conserved between mice and humans. The role of mitochondrially-encoded tRNA-derived fragments remains unknown. This study aimed to characterize the impact of mt-tRF-Leu<sup>TAA</sup>, on mitochondrial metabolism and pancreatic islet functions.</p></div><div><h3>Methods</h3><p>We used antisense oligonucleotides to reduce mt-tRF-Leu<sup>TAA</sup> levels in primary rat and human islet cells, as well as in insulin-secreting cell lines. We performed a joint transcriptome and proteome analysis upon mt-tRF-Leu<sup>TAA</sup> inhibition. Additionally, we employed pull-down assays followed by mass spectrometry to identify direct interactors of the fragment. Finally, we characterized the impact of mt-tRF-Leu<sup>TAA</sup> silencing on the coupling between mitochondrial metabolism and insulin secretion using high-resolution respirometry and insulin secretion assays.</p></div><div><h3>Results</h3><p>Our study unveils a modulation of mt-tRF-Leu<sup>TAA</sup> levels in pancreatic islets in different Type 2 diabetes models and in response to changes in nutritional status. The level of the fragment is finely tuned by the mechanistic target of rapamycin complex 1. Located within mitochondria, mt-tRF-Leu<sup>TAA</sup> interacts with core subunits and assembly factors of respiratory complexes of the electron transfer system. Silencing of mt-tRF-Leu<sup>TAA</sup> in islet cells limits the inner mitochondrial membrane potential and impairs mitochondrial oxidative phosphorylation, predominantly by affecting the Succinate (via Complex II)-linked electron transfer pathway. Lowering mt-tRF-Leu<sup>TAA</sup> impairs insulin secretion of rat and human pancreatic β-cells.</p></div><div><h3>Conclusions</h3><p>Our findings indicate that mt-tRF-Leu<sup>TAA</sup> interacts with electron transfer system complexes and is a pivotal regulator of mitochondrial oxidative phosphorylation and its coupling to insulin secretion.</p></div>","PeriodicalId":18765,"journal":{"name":"Molecular Metabolism","volume":null,"pages":null},"PeriodicalIF":8.1,"publicationDate":"2024-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2212877824000863/pdfft?md5=130e63b06f1481887e27a9cde022c370&pid=1-s2.0-S2212877824000863-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140867760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-01DOI: 10.1016/j.molmet.2024.101919
Ting Xiang, Liang Ma
{"title":"Letter-to-the-editor on “Acetyl-CoA synthetase (ACSS2) does not generate butyryl- and crotonyl-CoA”","authors":"Ting Xiang, Liang Ma","doi":"10.1016/j.molmet.2024.101919","DOIUrl":"10.1016/j.molmet.2024.101919","url":null,"abstract":"","PeriodicalId":18765,"journal":{"name":"Molecular Metabolism","volume":null,"pages":null},"PeriodicalIF":8.1,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2212877824000504/pdfft?md5=e26454206a38b518f4af020c4e8f59f3&pid=1-s2.0-S2212877824000504-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140184865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-01DOI: 10.1016/j.molmet.2024.101920
Uwe Schlattner, Saadi Khochbin, Carlo Petosa
{"title":"Response to letter-to-the-editor: “Acetyl-CoA synthetase (ACSS2) does not generate butyryl- and crotonyl-CoA”","authors":"Uwe Schlattner, Saadi Khochbin, Carlo Petosa","doi":"10.1016/j.molmet.2024.101920","DOIUrl":"10.1016/j.molmet.2024.101920","url":null,"abstract":"","PeriodicalId":18765,"journal":{"name":"Molecular Metabolism","volume":null,"pages":null},"PeriodicalIF":8.1,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2212877824000516/pdfft?md5=a0ddc4144bddd3525af16c6a6bc74d1d&pid=1-s2.0-S2212877824000516-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140184866","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-01DOI: 10.1016/j.molmet.2024.101935
Tobias Boothe , Gareth E. Lim , Haoning Cen , Søs Skovsø , Micah Piske , Shu Nan Li , Ivan R. Nabi , Patrick Gilon , James D. Johnson
{"title":"Corrigendum to “Inter-domain tagging implicates caveolin-1 in insulin receptor trafficking and Erk signaling bias in pancreatic beta-cells” [Mol Metab 2016 May; 5 (5): 366–378]","authors":"Tobias Boothe , Gareth E. Lim , Haoning Cen , Søs Skovsø , Micah Piske , Shu Nan Li , Ivan R. Nabi , Patrick Gilon , James D. Johnson","doi":"10.1016/j.molmet.2024.101935","DOIUrl":"10.1016/j.molmet.2024.101935","url":null,"abstract":"","PeriodicalId":18765,"journal":{"name":"Molecular Metabolism","volume":null,"pages":null},"PeriodicalIF":8.1,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2212877824000668/pdfft?md5=fc178f72e7eea18d5185e83f444dc1c5&pid=1-s2.0-S2212877824000668-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140584087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Corrigendum to “Elevation of hypothalamic ketone bodies induces a decrease in energy expenditures and an increase risk of metabolic disorder” [Mol Metab, 83 (2024) 101926]","authors":"Lionel Carneiro , Rocco Bernasconi , Adriano Bernini , Cendrine Repond , Luc Pellerin","doi":"10.1016/j.molmet.2024.101937","DOIUrl":"10.1016/j.molmet.2024.101937","url":null,"abstract":"","PeriodicalId":18765,"journal":{"name":"Molecular Metabolism","volume":null,"pages":null},"PeriodicalIF":8.1,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2212877824000681/pdfft?md5=ee85be5283f30def43c6b236f277f8ad&pid=1-s2.0-S2212877824000681-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140583997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-30DOI: 10.1016/j.molmet.2024.101950
Kripa Shankar , Nathan P. Metzger , Connor Lawrence , Deepali Gupta , Sherri Osborne-Lawrence , Salil Varshney , Omprakash Singh , Corine P. Richard , Alexander N. Zaykov , Rebecca Rolfts , Barent N. DuBois , Diego Perez-Tilve , Bharath K. Mani , Suntrea T.G. Hammer , Jeffrey M. Zigman
Objective
The number of individuals affected by metabolic dysfunction associated fatty liver disease [1] is on the rise, yet hormonal contributors to the condition remain incompletely described and only a single FDA-approved treatment is available. Some studies suggest that the hormones ghrelin and LEAP2, which act as agonist and antagonist/inverse agonist, respectively, for the G protein coupled receptor GHSR, may influence the development of MAFLD. For instance, ghrelin increases hepatic fat whereas synthetic GHSR antagonists do the opposite. Also, hepatic steatosis is less prominent in standard chow-fed ghrelin-KO mice but more prominent in 42% high-fat diet-fed female LEAP2-KO mice.
Methods
Here, we sought to determine the therapeutic potential of a long-acting LEAP2 analog (LA-LEAP2) to treat MAFLD in mice. LEAP2-KO and wild-type littermate mice were fed a Gubra-Amylin-NASH (GAN) diet for 10 or 40 wks, with some randomized to an additional 28 or 10 days of GAN diet, respectively, while treated with LA-LEAP2 vs Vehicle. Various metabolic parameters were followed and biochemical and histological assessments of MAFLD were made.
Results
Among the most notable metabolic effects, daily LA-LEAP2 administration to both LEAP2-KO and wild-type littermates during the final 4 wks of a 14 wk-long GAN diet challenge markedly reduced liver weight, hepatic triglycerides, plasma ALT, hepatic microvesicular steatosis, hepatic lobular inflammation, NASH activity scores, and prevalence of higher-grade fibrosis. These changes were accompanied by prominent reductions in body weight, without effects on food intake, and reduced plasma total cholesterol. Daily LA-LEAP2 administration during the final 10 d of a 41.5 wk-long GAN diet challenge also reduced body weight, plasma ALT, and plasma total cholesterol in LEAP2-KO and wild-type littermates and prevalence of higher grade fibrosis in LEAP2-KO mice.
Conclusions
Administration of LA-LEAP2 to mice fed a MAFLD-prone diet markedly improves several facets of MAFLD, including hepatic steatosis, hepatic lobular inflammation, higher-grade hepatic fibrosis, and transaminitis. These changes are accompanied by prominent reductions in body weight and lowered plasma total cholesterol. Taken together, these data suggest that LEAP2 analogs such as LA-LEAP2 hold promise for the treatment of MAFLD and obesity.
{"title":"A long-acting LEAP2 analog reduces hepatic steatosis and inflammation and causes marked weight loss in mice","authors":"Kripa Shankar , Nathan P. Metzger , Connor Lawrence , Deepali Gupta , Sherri Osborne-Lawrence , Salil Varshney , Omprakash Singh , Corine P. Richard , Alexander N. Zaykov , Rebecca Rolfts , Barent N. DuBois , Diego Perez-Tilve , Bharath K. Mani , Suntrea T.G. Hammer , Jeffrey M. Zigman","doi":"10.1016/j.molmet.2024.101950","DOIUrl":"10.1016/j.molmet.2024.101950","url":null,"abstract":"<div><h3>Objective</h3><p>The number of individuals affected by metabolic dysfunction associated fatty liver disease [1] is on the rise, yet hormonal contributors to the condition remain incompletely described and only a single FDA-approved treatment is available. Some studies suggest that the hormones ghrelin and LEAP2, which act as agonist and antagonist/inverse agonist, respectively, for the G protein coupled receptor GHSR, may influence the development of MAFLD. For instance, ghrelin increases hepatic fat whereas synthetic GHSR antagonists do the opposite. Also, hepatic steatosis is less prominent in standard chow-fed ghrelin-KO mice but more prominent in 42% high-fat diet-fed female LEAP2-KO mice.</p></div><div><h3>Methods</h3><p>Here, we sought to determine the therapeutic potential of a long-acting LEAP2 analog (LA-LEAP2) to treat MAFLD in mice. LEAP2-KO and wild-type littermate mice were fed a Gubra-Amylin-NASH (GAN) diet for 10 or 40 wks, with some randomized to an additional 28 or 10 days of GAN diet, respectively, while treated with LA-LEAP2 vs Vehicle. Various metabolic parameters were followed and biochemical and histological assessments of MAFLD were made.</p></div><div><h3>Results</h3><p>Among the most notable metabolic effects, daily LA-LEAP2 administration to both LEAP2-KO and wild-type littermates during the final 4 wks of a 14 wk-long GAN diet challenge markedly reduced liver weight, hepatic triglycerides, plasma ALT, hepatic microvesicular steatosis, hepatic lobular inflammation, NASH activity scores, and prevalence of higher-grade fibrosis. These changes were accompanied by prominent reductions in body weight, without effects on food intake, and reduced plasma total cholesterol. Daily LA-LEAP2 administration during the final 10 d of a 41.5 wk-long GAN diet challenge also reduced body weight, plasma ALT, and plasma total cholesterol in LEAP2-KO and wild-type littermates and prevalence of higher grade fibrosis in LEAP2-KO mice.</p></div><div><h3>Conclusions</h3><p>Administration of LA-LEAP2 to mice fed a MAFLD-prone diet markedly improves several facets of MAFLD, including hepatic steatosis, hepatic lobular inflammation, higher-grade hepatic fibrosis, and transaminitis. These changes are accompanied by prominent reductions in body weight and lowered plasma total cholesterol. Taken together, these data suggest that LEAP2 analogs such as LA-LEAP2 hold promise for the treatment of MAFLD and obesity.</p></div>","PeriodicalId":18765,"journal":{"name":"Molecular Metabolism","volume":null,"pages":null},"PeriodicalIF":8.1,"publicationDate":"2024-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2212877824000814/pdfft?md5=c284ebfbcfa89e00fc4a7ee8d25194df&pid=1-s2.0-S2212877824000814-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140862917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-26DOI: 10.1016/j.molmet.2024.101947
K. Suba , Y. Patel , A. Martin-Alonso , B. Hansen , X. Xu , A. Roberts , M. Norton , P. Chung , J. Shrewsbury , R. Kwok , V. Kalogianni , S. Chen , X. Liu , K. Kalyviotis , G.A. Rutter , B. Jones , J. Minnion , B.M. Owen , P. Pantazis , W. Distaso , V. Salem
Objective
Type 2 diabetes (T2D) is characterised by the loss of first-phase insulin secretion. We studied mice with β-cell selective loss of the glucagon receptor (Gcgrfl/fl X Ins-1Cre), to investigate the role of intra-islet glucagon receptor (GCGR) signalling on pan-islet [Ca2+]I activity and insulin secretion.
Methods
Metabolic profiling was conducted on Gcgrβ-cell−/− and littermate controls. Crossing with GCaMP6f (STOP flox) animals further allowed for β-cell specific expression of a fluorescent calcium indicator. These islets were functionally imaged in vitro and in vivo. Wild-type mice were transplanted with islets expressing GCaMP6f in β-cells into the anterior eye chamber and placed on a high fat diet. Part of the cohort received a glucagon analogue (GCG-analogue) for 40 days and the control group were fed to achieve weight matching. Calcium imaging was performed regularly during the development of hyperglycaemia and in response to GCG-analogue treatment.
Results
Gcgrβ-cell−/− mice exhibited higher glucose levels following intraperitoneal glucose challenge (control 12.7 mmol/L ± 0.6 vs. Gcgrβ-cell−/− 15.4 mmol/L ± 0.0 at 15 min, p = 0.002); fasting glycaemia was not different to controls. In vitro, Gcgrβ-cell−/− islets showed profound loss of pan-islet [Ca2+]I waves in response to glucose which was only partially rescued in vivo. Diet induced obesity and hyperglycaemia also resulted in a loss of co-ordinated [Ca2+]I waves in transplanted islets. This was reversed with GCG-analogue treatment, independently of weight-loss (n = 8).
Conclusion
These data provide novel evidence for the role of intra-islet GCGR signalling in sustaining synchronised [Ca2+]I waves and support a possible therapeutic role for glucagonergic agents to restore the insulin secretory capacity lost in T2D.
{"title":"Intra-islet glucagon signalling regulates beta-cell connectivity, first-phase insulin secretion and glucose homoeostasis","authors":"K. Suba , Y. Patel , A. Martin-Alonso , B. Hansen , X. Xu , A. Roberts , M. Norton , P. Chung , J. Shrewsbury , R. Kwok , V. Kalogianni , S. Chen , X. Liu , K. Kalyviotis , G.A. Rutter , B. Jones , J. Minnion , B.M. Owen , P. Pantazis , W. Distaso , V. Salem","doi":"10.1016/j.molmet.2024.101947","DOIUrl":"10.1016/j.molmet.2024.101947","url":null,"abstract":"<div><h3>Objective</h3><p>Type 2 diabetes (T2D) is characterised by the loss of first-phase insulin secretion. We studied mice with β-cell selective loss of the glucagon receptor (Gcgr<sup><em>fl/fl</em></sup> X Ins-1<sup><em>Cre</em></sup>), to investigate the role of intra-islet glucagon receptor (GCGR) signalling on pan-islet [Ca<sup>2+</sup>]<sub>I</sub> activity and insulin secretion.</p></div><div><h3>Methods</h3><p>Metabolic profiling was conducted on Gcgr<sup><em>β-cell−/−</em></sup> and littermate controls. Crossing with GCaMP6f (STOP flox) animals further allowed for β-cell specific expression of a fluorescent calcium indicator. These islets were functionally imaged <em>in vitro</em> and <em>in vivo</em>. Wild-type mice were transplanted with islets expressing GCaMP6f in β-cells into the anterior eye chamber and placed on a high fat diet. Part of the cohort received a glucagon analogue (GCG-analogue) for 40 days and the control group were fed to achieve weight matching. Calcium imaging was performed regularly during the development of hyperglycaemia and in response to GCG-analogue treatment.</p></div><div><h3>Results</h3><p>Gcgr<sup><em>β-cell−/−</em></sup> mice exhibited higher glucose levels following intraperitoneal glucose challenge (control 12.7 mmol/L ± 0.6 vs. Gcgr<sup><em>β-cell−/−</em></sup> 15.4 mmol/L ± 0.0 at 15 min, <em>p</em> = 0.002); fasting glycaemia was not different to controls. <em>In vitro</em>, Gcgr<sup><em>β-cell−/−</em></sup> islets showed profound loss of pan-islet [Ca<sup>2+</sup>]<sub>I</sub> waves in response to glucose which was only partially rescued <em>in vivo</em>. Diet induced obesity and hyperglycaemia also resulted in a loss of co-ordinated [Ca<sup>2+</sup>]<sub>I</sub> waves in transplanted islets. This was reversed with GCG-analogue treatment, independently of weight-loss (n = 8).</p></div><div><h3>Conclusion</h3><p>These data provide novel evidence for the role of intra-islet GCGR signalling in sustaining synchronised [Ca<sup>2+</sup>]<sub>I</sub> waves and support a possible therapeutic role for glucagonergic agents to restore the insulin secretory capacity lost in T2D.</p></div>","PeriodicalId":18765,"journal":{"name":"Molecular Metabolism","volume":null,"pages":null},"PeriodicalIF":8.1,"publicationDate":"2024-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2212877824000784/pdfft?md5=f4ea3b4a092124716185df1b1ecbf067&pid=1-s2.0-S2212877824000784-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140839185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-25DOI: 10.1016/j.molmet.2024.101948
Kyungchan Kim , Jamie Wann , Hyeong-Geug Kim , Jisun So , Evan D. Rosen , Hyun Cheol Roh
Objective
Uncoupling protein 1 (UCP1), a mitochondrial protein responsible for nonshivering thermogenesis in adipose tissue, serves as a distinct marker for thermogenic brown and beige adipocytes. Ucp1-Cre mice are thus widely used to genetically manipulate these thermogenic adipocytes. However, evidence suggests that UCP1 may also be expressed in non-adipocyte cell types. In this study, we investigated the presence of UCP1 expression in different mouse tissues that have not been previously reported.
Methods
We employed Ucp1-Cre mice crossed with Cre-inducible transgenic reporter Nuclear tagging and Translating Ribosome Affinity Purification (NuTRAP) mice to investigate Ucp1-Cre expression in various tissues of adult female mice and developing embryos. Tamoxifen-inducible Ucp1-CreERT2 mice crossed with NuTRAP mice were used to assess active Ucp1 expression in adult mice. Immunostaining, RNA analysis, and single-cell/nucleus RNA-seq (sc/snRNA-seq) data analysis were performed to determine the expression of endogenous UCP1 and Ucp1-Cre-driven reporter expression. We also investigated the impact of UCP1 deficiency on mammary gland development and function using Ucp1-knockout (KO) mice.
Results
Ucp1-Cre expression was observed in the mammary glands within the inguinal white adipose tissue of female Ucp1-Cre; NuTRAP mice. Ucp1-Cre was activated during embryonic development in various tissues, including mammary glands, as well as in the brain, kidneys, eyes, and ears, specifically in epithelial cells in these organs. However, Ucp1-CreERT2 showed no or only partial activation in these tissues of adult mice, indicating the potential for low or transient expression of endogenous Ucp1. While sc/snRNA-seq data suggest potential expression of UCP1 in mammary epithelial cells in adult mice and humans, Ucp1-KO female mice displayed normal mammary gland development and function.
Conclusions
Our findings reveal widespread Ucp1-Cre expression in various non-adipose tissue types, starting during early development. These results highlight the importance of exercising caution when interpreting data and devising experiments involving Ucp1-Cre mice.
{"title":"Uncoupling protein 1-driven Cre (Ucp1-Cre) is expressed in the epithelial cells of mammary glands and various non-adipose tissues","authors":"Kyungchan Kim , Jamie Wann , Hyeong-Geug Kim , Jisun So , Evan D. Rosen , Hyun Cheol Roh","doi":"10.1016/j.molmet.2024.101948","DOIUrl":"https://doi.org/10.1016/j.molmet.2024.101948","url":null,"abstract":"<div><h3>Objective</h3><p>Uncoupling protein 1 (UCP1), a mitochondrial protein responsible for nonshivering thermogenesis in adipose tissue, serves as a distinct marker for thermogenic brown and beige adipocytes. <em>Ucp1-Cre</em> mice are thus widely used to genetically manipulate these thermogenic adipocytes. However, evidence suggests that UCP1 may also be expressed in non-adipocyte cell types. In this study, we investigated the presence of UCP1 expression in different mouse tissues that have not been previously reported.</p></div><div><h3>Methods</h3><p>We employed <em>Ucp1-Cre</em> mice crossed with Cre-inducible transgenic reporter Nuclear tagging and Translating Ribosome Affinity Purification (NuTRAP) mice to investigate <em>Ucp1</em>-<em>Cre</em> expression in various tissues of adult female mice and developing embryos. Tamoxifen-inducible <em>Ucp1-CreERT2</em> mice crossed with NuTRAP mice were used to assess active <em>Ucp1</em> expression in adult mice. Immunostaining, RNA analysis, and single-cell/nucleus RNA-seq (sc/snRNA-seq) data analysis were performed to determine the expression of endogenous UCP1 and <em>Ucp1-Cre</em>-driven reporter expression. We also investigated the impact of UCP1 deficiency on mammary gland development and function using <em>Ucp1</em>-knockout (KO) mice.</p></div><div><h3>Results</h3><p><em>Ucp1-Cre</em> expression was observed in the mammary glands within the inguinal white adipose tissue of female <em>Ucp1-Cre</em>; NuTRAP mice. <em>Ucp1-Cre</em> was activated during embryonic development in various tissues, including mammary glands, as well as in the brain, kidneys, eyes, and ears, specifically in epithelial cells in these organs. However, <em>Ucp1-CreERT2</em> showed no or only partial activation in these tissues of adult mice, indicating the potential for low or transient expression of endogenous <em>Ucp1</em>. While sc/snRNA-seq data suggest potential expression of UCP1 in mammary epithelial cells in adult mice and humans, <em>Ucp1</em>-KO female mice displayed normal mammary gland development and function.</p></div><div><h3>Conclusions</h3><p>Our findings reveal widespread <em>Ucp1-Cre</em> expression in various non-adipose tissue types, starting during early development. These results highlight the importance of exercising caution when interpreting data and devising experiments involving <em>Ucp1-Cre</em> mice.</p></div>","PeriodicalId":18765,"journal":{"name":"Molecular Metabolism","volume":null,"pages":null},"PeriodicalIF":8.1,"publicationDate":"2024-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2212877824000796/pdfft?md5=2dd886159b3e290fb7fce24fd7d83585&pid=1-s2.0-S2212877824000796-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140815616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Adipose tissue is an endocrine and energy storage organ composed of several different cell types, including mature adipocytes, stromal cells, endothelial cells, and a variety of immune cells. Adipose tissue aging contributes to the pathogenesis of metabolic dysfunction and is likely induced by crosstalk between adipose progenitor cells (APCs) and immune cells, but the underlying molecular mechanisms remain largely unknown. In this study, we revealed the biological role of p16high senescent APCs, and investigated the crosstalk between each cell type in the aged white adipose tissue.
Methods
We performed the single-cell RNA sequencing (scRNA-seq) analysis on the p16high adipose cells sorted from aged p16-CreERT2/Rosa26-LSL-tdTomato mice. We also performed the time serial analysis on the age-dependent bulk RNA-seq datasets of human and mouse white adipose tissues to infer the transcriptome alteration of adipogenic potential within aging.
Results
We show that M2 macrophage-derived TGF-β induces APCs senescence which impairs adipogenesis in vivo. p16high senescent APCs increase with age and show loss of adipogenic potential. The ligand–receptor interaction analysis reveals that M2 macrophages are the donors for TGF-β and the senescent APCs are the recipients. Indeed, treatment of APCs with TGF-β1 induces senescent phenotypes through mitochondrial ROS-mediated DNA damage in vitro. TGF-β1 injection into gonadal white adipose tissue (gWAT) suppresses adipogenic potential and induces fibrotic genes as well as p16 in APCs. A gWAT atrophy is observed in cancer cachexia by APCs senescence, whose induction appeared to be independent of TGF-β induction.
Conclusions
Our results suggest that M2 macrophage-derived TGF-β induces age-related lipodystrophy by APCs senescence. The TGF-β treatment induced DNA damage, mitochondrial ROS, and finally cellular senescence in APCs.
{"title":"M2 macrophage-derived TGF-β induces age-associated loss of adipogenesis through progenitor cell senescence","authors":"Xinyi Zeng , Teh-Wei Wang , Kiyoshi Yamaguchi , Seira Hatakeyama , Satoshi Yamazaki , Eigo Shimizu , Seiya Imoto , Yoichi Furukawa , Yoshikazu Johmura , Makoto Nakanishi","doi":"10.1016/j.molmet.2024.101943","DOIUrl":"10.1016/j.molmet.2024.101943","url":null,"abstract":"<div><h3>Objectives</h3><p>Adipose tissue is an endocrine and energy storage organ composed of several different cell types, including mature adipocytes, stromal cells, endothelial cells, and a variety of immune cells. Adipose tissue aging contributes to the pathogenesis of metabolic dysfunction and is likely induced by crosstalk between adipose progenitor cells (APCs) and immune cells, but the underlying molecular mechanisms remain largely unknown. In this study, we revealed the biological role of p16<sup>high</sup> senescent APCs, and investigated the crosstalk between each cell type in the aged white adipose tissue.</p></div><div><h3>Methods</h3><p>We performed the single-cell RNA sequencing (scRNA-seq) analysis on the p16<sup>high</sup> adipose cells sorted from aged p16-Cre<sup>ERT2</sup>/Rosa26-LSL-tdTomato mice. We also performed the time serial analysis on the age-dependent bulk RNA-seq datasets of human and mouse white adipose tissues to infer the transcriptome alteration of adipogenic potential within aging.</p></div><div><h3>Results</h3><p>We show that M2 macrophage-derived TGF-β induces APCs senescence which impairs adipogenesis <em>in vivo</em>. p16<sup>high</sup> senescent APCs increase with age and show loss of adipogenic potential. The ligand–receptor interaction analysis reveals that M2 macrophages are the donors for TGF-β and the senescent APCs are the recipients. Indeed, treatment of APCs with TGF-β1 induces senescent phenotypes through mitochondrial ROS-mediated DNA damage <em>in vitro</em>. TGF-β1 injection into gonadal white adipose tissue (gWAT) suppresses adipogenic potential and induces fibrotic genes as well as p16 in APCs. A gWAT atrophy is observed in cancer cachexia by APCs senescence, whose induction appeared to be independent of TGF-β induction.</p></div><div><h3>Conclusions</h3><p>Our results suggest that M2 macrophage-derived TGF-β induces age-related lipodystrophy by APCs senescence. The TGF-β treatment induced DNA damage, mitochondrial ROS, and finally cellular senescence in APCs.</p></div>","PeriodicalId":18765,"journal":{"name":"Molecular Metabolism","volume":null,"pages":null},"PeriodicalIF":8.1,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2212877824000747/pdfft?md5=7a9bc93c94ee7dab78d63a3d6cf992f8&pid=1-s2.0-S2212877824000747-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140794508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-23DOI: 10.1016/j.molmet.2024.101946
Vojtěch Škop , Naili Liu , Cuiying Xiao , Emma Stinson , Kong Y. Chen , Kevin D. Hall , Paolo Piaggi , Oksana Gavrilova , Marc L. Reitman
Our circadian world shapes much of metabolic physiology. In mice ∼40% of the light and ∼80% of the dark phase time is characterized by bouts of increased energy expenditure (EE). These ultradian bouts have a higher body temperature (Tb) and thermal conductance and contain virtually all of the physical activity and awake time. Bout status is a better classifier of mouse physiology than photoperiod, with ultradian bouts superimposed on top of the circadian light/dark cycle. We suggest that the primary driver of ultradian bouts is a brain-initiated transition to a higher defended Tb of the active/awake state. Increased energy expenditure from brown adipose tissue, physical activity, and cardiac work combine to raise Tb from the lower defended Tb of the resting/sleeping state. Thus, unlike humans, much of mouse metabolic physiology is episodic with large ultradian increases in EE and Tb that correlate with the active/awake state and are poorly aligned with circadian cycling.
{"title":"Beyond day and night: The importance of ultradian rhythms in mouse physiology","authors":"Vojtěch Škop , Naili Liu , Cuiying Xiao , Emma Stinson , Kong Y. Chen , Kevin D. Hall , Paolo Piaggi , Oksana Gavrilova , Marc L. Reitman","doi":"10.1016/j.molmet.2024.101946","DOIUrl":"10.1016/j.molmet.2024.101946","url":null,"abstract":"<div><p>Our circadian world shapes much of metabolic physiology. In mice ∼40% of the light and ∼80% of the dark phase time is characterized by bouts of increased energy expenditure (EE). These ultradian bouts have a higher body temperature (Tb) and thermal conductance and contain virtually all of the physical activity and awake time. Bout status is a better classifier of mouse physiology than photoperiod, with ultradian bouts superimposed on top of the circadian light/dark cycle. We suggest that the primary driver of ultradian bouts is a brain-initiated transition to a higher defended Tb of the active/awake state. Increased energy expenditure from brown adipose tissue, physical activity, and cardiac work combine to raise Tb from the lower defended Tb of the resting/sleeping state. Thus, unlike humans, much of mouse metabolic physiology is episodic with large ultradian increases in EE and Tb that correlate with the active/awake state and are poorly aligned with circadian cycling.</p></div>","PeriodicalId":18765,"journal":{"name":"Molecular Metabolism","volume":null,"pages":null},"PeriodicalIF":8.1,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2212877824000772/pdfft?md5=fd71858cf6575f2988dca84de5f54db2&pid=1-s2.0-S2212877824000772-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140755989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}