Pub Date : 2024-10-24DOI: 10.1016/j.metabol.2024.156048
Tong-Tong Yang , Liu-Hua Zhou , Ling-Feng Gu , Ling-Ling Qian , Yu-Lin Bao , Peng Jing , Jia-Teng Sun , Chong Du , Tian-Kai Shan , Si-Bo Wang , Wen-Jing Wang , Jia-Yi Chen , Ze-Mu Wang , Hao Wang , Qi-Ming Wang , Ru-Xing Wang , Lian-Sheng Wang
Background
Mitochondrial dysfunction is linked to myocardial ischemia-reperfusion (I/R) injury. Checkpoint kinase 1 (CHK1) could facilitate cardiomyocyte proliferation, however, its role on mitochondrial function in I/R injury remains unknown.
Methods
To investigate the role of CHK1 on mitochondrial function following I/R injury, cardiomyocyte-specific knockout/overexpression mouse models were generated. Adult mouse cardiomyocytes (AMCMs) were isolated for in vitro study. Mass spectrometry-proteomics analysis and protein co-immunoprecipitation assays were conducted to dissect the molecular mechanism.
Results
CHK1 was downregulated in myocardium post I/R and AMCMs post oxygen-glucose deprivation/re‑oxygenation (OGD/R). In vivo, CHK1 overexpression protected against I/R induced cardiac dysfunction, while heterogenous CHK1 knockout exacerbated cardiomyopathy. In vitro, CHK1 inhibited OGD/R-induced cardiomyocyte apoptosis and bolstered cardiomyocyte survival. Mechanistically, CHK1 attenuated oxidative stress and preserved mitochondrial metabolism in cardiomyocytes under I/R. Moreover, disrupted mitochondrial homeostasis in I/R myocardium was restored by CHK1 through the promotion of mitochondrial biogenesis and mitophagy. Through mass spectrometry analysis following co-immunoprecipitation, SIRT1 was identified as a direct target of CHK1. The 266–390 domain of CHK1 interacted with the 160–583 domain of SIRT1. Importantly, CHK1 phosphorylated SIRT1 at Thr530 residue, thereby inhibiting SMURF2-mediated degradation of SIRT1. The role of CHK1 in maintaining mitochondrial dynamics control and myocardial protection is abolished by SIRT1 inhibition, while inactivated mutation of SIRT1 Thr530 fails to reverse the impaired mitochondrial dynamics following CHK1 knockdown. CHK1 Δ390 amino acids (aa) mutant functioned similarly to full-length CHK1 in scavenging ROS and maintaining mitochondrial dynamics. Consistently, cardiac-specific SIRT1 knockdown attenuated the protective role of CHK1 in I/R injury.
Conclusions
Our findings revealed that CHK1 mitigates I/R injury and restores mitochondrial dynamics in cardiomyocytes through a SIRT1-dependent mechanism.
{"title":"CHK1 attenuates cardiac dysfunction via suppressing SIRT1-ubiquitination","authors":"Tong-Tong Yang , Liu-Hua Zhou , Ling-Feng Gu , Ling-Ling Qian , Yu-Lin Bao , Peng Jing , Jia-Teng Sun , Chong Du , Tian-Kai Shan , Si-Bo Wang , Wen-Jing Wang , Jia-Yi Chen , Ze-Mu Wang , Hao Wang , Qi-Ming Wang , Ru-Xing Wang , Lian-Sheng Wang","doi":"10.1016/j.metabol.2024.156048","DOIUrl":"10.1016/j.metabol.2024.156048","url":null,"abstract":"<div><h3>Background</h3><div>Mitochondrial dysfunction is linked to myocardial ischemia-reperfusion (I/R) injury. Checkpoint kinase 1 (CHK1) could facilitate cardiomyocyte proliferation, however, its role on mitochondrial function in I/R injury remains unknown.</div></div><div><h3>Methods</h3><div>To investigate the role of CHK1 on mitochondrial function following I/R injury, cardiomyocyte-specific knockout/overexpression mouse models were generated. Adult mouse cardiomyocytes (AMCMs) were isolated for <em>in vitro</em> study. Mass spectrometry-proteomics analysis and protein co-immunoprecipitation assays were conducted to dissect the molecular mechanism.</div></div><div><h3>Results</h3><div>CHK1 was downregulated in myocardium post I/R and AMCMs post oxygen-glucose deprivation/re‑oxygenation (OGD/R). <em>In vivo</em>, CHK1 overexpression protected against I/R induced cardiac dysfunction, while heterogenous CHK1 knockout exacerbated cardiomyopathy. <em>In vitro</em>, CHK1 inhibited OGD/R-induced cardiomyocyte apoptosis and bolstered cardiomyocyte survival. Mechanistically, CHK1 attenuated oxidative stress and preserved mitochondrial metabolism in cardiomyocytes under I/R. Moreover, disrupted mitochondrial homeostasis in I/R myocardium was restored by CHK1 through the promotion of mitochondrial biogenesis and mitophagy. Through mass spectrometry analysis following co-immunoprecipitation, SIRT1 was identified as a direct target of CHK1. The 266–390 domain of CHK1 interacted with the 160–583 domain of SIRT1. Importantly, CHK1 phosphorylated SIRT1 at Thr530 residue, thereby inhibiting SMURF2-mediated degradation of SIRT1. The role of CHK1 in maintaining mitochondrial dynamics control and myocardial protection is abolished by SIRT1 inhibition, while inactivated mutation of SIRT1 Thr530 fails to reverse the impaired mitochondrial dynamics following CHK1 knockdown. CHK1 Δ390 amino acids (aa) mutant functioned similarly to full-length CHK1 in scavenging ROS and maintaining mitochondrial dynamics. Consistently, cardiac-specific SIRT1 knockdown attenuated the protective role of CHK1 in I/R injury.</div></div><div><h3>Conclusions</h3><div>Our findings revealed that CHK1 mitigates I/R injury and restores mitochondrial dynamics in cardiomyocytes through a SIRT1-dependent mechanism.</div></div>","PeriodicalId":18694,"journal":{"name":"Metabolism: clinical and experimental","volume":"162 ","pages":"Article 156048"},"PeriodicalIF":10.8,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142504210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-24DOI: 10.1016/j.metabol.2024.156049
Yuan-yuan Luo , Chang-shun Ruan , Fu-zhen Zhao , Min Yang , Wei Cui , Xi Cheng , Xiao-he Luo , Xian-xiang Zhang , Cheng Zhang
Background
Elevated hepatic glucose production (HGP) is a prominent manifestation of impaired hepatic glucose metabolism in individuals with diabetes. Increased hepatic gluconeogenesis plays a pivotal role in the dysregulation of hepatic glucose metabolism and contributes significantly to fasting hyperglycemia in diabetes. Previous studies have identified zinc-finger BED domain-containing 3 (ZBED3) as a risk gene for type 2 diabetes (T2DM), and its single nucleotide polymorphism (SNPs) is closely associated with the fasting blood glucose level, suggesting a potential correlation between ZBED3 and the onset of diabetes. This study primarily explores the effect of ZBED3 on hepatic gluconeogenesis and analyzes the relevant signaling pathways that regulate hepatic gluconeogenesis.
Methods
The expression level of ZBED3 was assessed in the liver of insulin-resistant (IR)-related disease. RNA-seq and bioinformatics analyses were employed to examine the ZBED3-related pathway that modulated HGP. To investigate the role of ZBED3 in hepatic gluconeogenesis, the expression of ZBED3 was manipulated by upregulation or silencing using adeno-associated virus (AAV) in mouse primary hepatocytes (MPHs) and HHL-5 cells. In vivo, hepatocyte-specific ZBED3 knockout mice were generated. Moreover, AAV8 was employed to achieve hepatocyte-specific overexpression and knockdown of ZBED3 in C57BL/6 and db/db mice. Immunoprecipitation and mass spectrometry (IP-MS) analyses were employed to identify proteins that interacted with ZBED3. Co-immunoprecipitation (co-IP), glutathione S-transferase (GST) - pulldown, and dual-luciferase reporter assays were conducted to further elucidate the underlying mechanism of ZBED3 in regulating hepatic gluconeogenesis.
Results
The expression of ZBED3 in the liver of IR-related disease models was found to be increased. Under the stimulation of glucagon, ZBED3 promoted the expression of hepatic gluconeogenesis-related genes PGC1A, PCK1, G6PC, thereby increasing HGP. Consistently, the rate of hepatic gluconeogenesis was found to be elevated in mice with hepatocyte-specific overexpression of ZBED3 and decreased in those with ZBED3 knockout. Additionally, the knockdown of ZBED3 in the liver of db/db mice resulted in a reduction in hepatic gluconeogenesis. Moreover, the study revealed that ZBED3 facilitated the nuclear translocation of protein arginine methyltransferases 5 (PRMT5) to influence the regulation of PRMT5-mediated symmetrical dimethylation of arginine (s-DMA) of cyclic adenosine monophosphate (cAMP) response element binding protein (CREB), which in turn affects the phosphorylation of CREB and ultimately promotes HGP.
Conclusions
This study indicates that ZBED3 promotes hepatic gluconeogenesis and serves as a critical regulator of the progression of diabetes.
{"title":"ZBED3 exacerbates hyperglycemia by promoting hepatic gluconeogenesis through CREB signaling","authors":"Yuan-yuan Luo , Chang-shun Ruan , Fu-zhen Zhao , Min Yang , Wei Cui , Xi Cheng , Xiao-he Luo , Xian-xiang Zhang , Cheng Zhang","doi":"10.1016/j.metabol.2024.156049","DOIUrl":"10.1016/j.metabol.2024.156049","url":null,"abstract":"<div><h3>Background</h3><div>Elevated hepatic glucose production (HGP) is a prominent manifestation of impaired hepatic glucose metabolism in individuals with diabetes. Increased hepatic gluconeogenesis plays a pivotal role in the dysregulation of hepatic glucose metabolism and contributes significantly to fasting hyperglycemia in diabetes. Previous studies have identified zinc-finger BED domain-containing 3 (<em>ZBED3</em>) as a risk gene for type 2 diabetes (T2DM), and its single nucleotide polymorphism (SNPs) is closely associated with the fasting blood glucose level, suggesting a potential correlation between ZBED3 and the onset of diabetes. This study primarily explores the effect of ZBED3 on hepatic gluconeogenesis and analyzes the relevant signaling pathways that regulate hepatic gluconeogenesis.</div></div><div><h3>Methods</h3><div>The expression level of ZBED3 was assessed in the liver of insulin-resistant (IR)-related disease. RNA-seq and bioinformatics analyses were employed to examine the ZBED3-related pathway that modulated HGP. To investigate the role of ZBED3 in hepatic gluconeogenesis, the expression of ZBED3 was manipulated by upregulation or silencing using adeno-associated virus (AAV) in mouse primary hepatocytes (MPHs) and HHL-5 cells. In vivo, hepatocyte-specific ZBED3 knockout mice were generated. Moreover, AAV8 was employed to achieve hepatocyte-specific overexpression and knockdown of ZBED3 in C57BL/6 and db/db mice. Immunoprecipitation and mass spectrometry (IP-MS) analyses were employed to identify proteins that interacted with ZBED3. Co-immunoprecipitation (co-IP), glutathione S-transferase (GST) - pulldown, and dual-luciferase reporter assays were conducted to further elucidate the underlying mechanism of ZBED3 in regulating hepatic gluconeogenesis.</div></div><div><h3>Results</h3><div>The expression of ZBED3 in the liver of IR-related disease models was found to be increased. Under the stimulation of glucagon, ZBED3 promoted the expression of hepatic gluconeogenesis-related genes <em>PGC1A</em>, <em>PCK1</em>, <em>G6PC</em>, thereby increasing HGP. Consistently, the rate of hepatic gluconeogenesis was found to be elevated in mice with hepatocyte-specific overexpression of ZBED3 and decreased in those with ZBED3 knockout. Additionally, the knockdown of ZBED3 in the liver of db/db mice resulted in a reduction in hepatic gluconeogenesis. Moreover, the study revealed that ZBED3 facilitated the nuclear translocation of protein arginine methyltransferases 5 (PRMT5) to influence the regulation of PRMT5-mediated symmetrical dimethylation of arginine (s-DMA) of cyclic adenosine monophosphate (cAMP) response element binding protein (CREB), which in turn affects the phosphorylation of CREB and ultimately promotes HGP.</div></div><div><h3>Conclusions</h3><div>This study indicates that ZBED3 promotes hepatic gluconeogenesis and serves as a critical regulator of the progression of diabetes.</div></div>","PeriodicalId":18694,"journal":{"name":"Metabolism: clinical and experimental","volume":"162 ","pages":"Article 156049"},"PeriodicalIF":10.8,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142504212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-23DOI: 10.1016/j.metabol.2024.156051
Adrien Vouilloz , Thibaut Bourgeois , Marc Diedisheim , Thomas Pilot , Antoine Jalil , Naig Le Guern , Victoria Bergas , Noéline Rohmer , Florence Castelli , Damien Leleu , Alexis Varin , Jean-Paul Pais de Barros , Pascal Degrace , Mickael Rialland , Camille Blériot , Nicolas Venteclef , Charles Thomas , David Masson
Background and aims
Although qualitative and quantitative alterations in liver Polyunsaturated Fatty Acids (PUFAs) are observed in MASH in humans, a causal relationship of PUFAs biosynthetic pathways is yet to be clarified. ELOVL5, an essential enzyme in PUFA elongation regulates hepatic triglyceride metabolism. Nonetheless, the long-term consequences of elongase disruption, particularly in murine models of MASH, have not been evaluated.
Approach & results
In humans, transcriptomic data indicated that PUFAs biosynthesis enzymes and notably ELOVL5 were induced during MASH progression. Moreover, gene module association determination revealed that ELOVL5 expression was associated with mitochondrial function in both humans and mice. WT and Elovl5-deficient mice were fed a high-fat, high-sucrose (HF/HS) diet for four months. Elovl5 deficiency led to limited systemic metabolic alterations but significant hepatic phenotype was observed in Elovl5−/− mice after the HF/HS diet, including hepatomegaly, pronounced macrovesicular and microvesicular steatosis, hepatocyte ballooning, immune cell infiltration, and fibrosis. Lipid analysis confirmed hepatic triglyceride accumulation and a reshaping of FA profile. Transcriptomic analysis indicated significant upregulation of genes involved in immune cell recruitment and fibrosis, and downregulation of genes involved in oxidative phosphorylation in Elovl5−/− mice. Alterations of FA oxidation and energy metabolism were confirmed by non-targeted metabolomic approach. Analysis of mitochondrial function in Elovl5−/− mice showed morphological alterations, qualitative cardiolipin changes with an enrichment in species containing shorter unsaturated FAs, and decreased activity of I and III respiratory chain complexes.
Conclusion
Enhanced susceptibility to diet-induced MASH and fibrosis in Elovl5−/− mice is intricately associated with disruptions in mitochondrial homeostasis, stemming from a profound reshaping of mitochondrial lipids, notably cardiolipins.
{"title":"Impaired unsaturated fatty acid elongation alters mitochondrial function and accelerates metabolic dysfunction-associated steatohepatitis progression","authors":"Adrien Vouilloz , Thibaut Bourgeois , Marc Diedisheim , Thomas Pilot , Antoine Jalil , Naig Le Guern , Victoria Bergas , Noéline Rohmer , Florence Castelli , Damien Leleu , Alexis Varin , Jean-Paul Pais de Barros , Pascal Degrace , Mickael Rialland , Camille Blériot , Nicolas Venteclef , Charles Thomas , David Masson","doi":"10.1016/j.metabol.2024.156051","DOIUrl":"10.1016/j.metabol.2024.156051","url":null,"abstract":"<div><h3>Background and aims</h3><div>Although qualitative and quantitative alterations in liver Polyunsaturated Fatty Acids (PUFAs) are observed in MASH in humans, a causal relationship of PUFAs biosynthetic pathways is yet to be clarified. ELOVL5, an essential enzyme in PUFA elongation regulates hepatic triglyceride metabolism. Nonetheless, the long-term consequences of elongase disruption, particularly in murine models of MASH, have not been evaluated.</div></div><div><h3>Approach & results</h3><div>In humans, transcriptomic data indicated that PUFAs biosynthesis enzymes and notably ELOVL5 were induced during MASH progression. Moreover, gene module association determination revealed that ELOVL5 expression was associated with mitochondrial function in both humans and mice. WT and <em>Elovl5</em>-deficient mice were fed a high-fat, high-sucrose (HF/HS) diet for four months. <em>Elovl5</em> deficiency led to limited systemic metabolic alterations but significant hepatic phenotype was observed in <em>Elovl5</em>−/− mice after the HF/HS diet, including hepatomegaly, pronounced macrovesicular and microvesicular steatosis, hepatocyte ballooning, immune cell infiltration, and fibrosis. Lipid analysis confirmed hepatic triglyceride accumulation and a reshaping of FA profile. Transcriptomic analysis indicated significant upregulation of genes involved in immune cell recruitment and fibrosis, and downregulation of genes involved in oxidative phosphorylation in <em>Elovl5</em>−/− mice. Alterations of FA oxidation and energy metabolism were confirmed by non-targeted metabolomic approach. Analysis of mitochondrial function in <em>Elovl5</em>−/− mice showed morphological alterations, qualitative cardiolipin changes with an enrichment in species containing shorter unsaturated FAs, and decreased activity of I and III respiratory chain complexes.</div></div><div><h3>Conclusion</h3><div>Enhanced susceptibility to diet-induced MASH and fibrosis in <em>Elovl5</em>−/− mice is intricately associated with disruptions in mitochondrial homeostasis, stemming from a profound reshaping of mitochondrial lipids, notably cardiolipins.</div></div>","PeriodicalId":18694,"journal":{"name":"Metabolism: clinical and experimental","volume":"162 ","pages":"Article 156051"},"PeriodicalIF":10.8,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142504211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Metabolic dysfunction-associated fatty liver disease (MAFLD) is a prevalent chronic liver condition characterised by dysregulated lipid metabolism. The role of Natriuretic Peptide Receptor C (NPRC), a receptor responsible for clearing natriuretic peptides, in MAFLD remains elusive. Therefore, the aim of the present study was to elucidate the role of NPRC in MAFLD progression.
Approach and results
This study demonstrated that NPRC enhanced lipid metabolism reprogramming and accelerated MAFLD progression. Mechanistic investigations, including proteomic and ubiquitination analyses, revealed that elevated NPRC levels stabilized the C/EBPβ protein, leading to excessive lipid accumulation. The DNA-binding domain (DBD) of C/EBPβ interacted with the deubiquitinase USP30, a key regulator that inhibited K149-specific K48-linked polyubiquitination of C/EBPβ. Importantly, the ANPR region of NPRC bound to USP30, facilitating the deubiquitination of C/EBPβ. Furthermore, virtual screening identified punicalin, a natural compound, as a potential inhibitor of NPRC expression, which may reduce hepatic lipid accumulation, inflammation and fibrosis.
Conclusions
Our findings indicate that NPRC recruits USP30 to mediate the deubiquitination of C/EBPβ, driving lipid metabolism reprogramming. Targeting NPRC could represent a promising therapeutic approach for MAFLD.
{"title":"NPRC promotes hepatic steatosis via USP30-mediated deubiquitination of C/EBPβ","authors":"Feng Jiang, Xinmiao Li, Lifan Lin, Mengyuan Li, Jianjian Zheng","doi":"10.1016/j.metabol.2024.156050","DOIUrl":"10.1016/j.metabol.2024.156050","url":null,"abstract":"<div><h3>Background and aims</h3><div>Metabolic dysfunction-associated fatty liver disease (MAFLD) is a prevalent chronic liver condition characterised by dysregulated lipid metabolism. The role of Natriuretic Peptide Receptor C (NPRC), a receptor responsible for clearing natriuretic peptides, in MAFLD remains elusive. Therefore, the aim of the present study was to elucidate the role of NPRC in MAFLD progression.</div></div><div><h3>Approach and results</h3><div>This study demonstrated that NPRC enhanced lipid metabolism reprogramming and accelerated MAFLD progression. Mechanistic investigations, including proteomic and ubiquitination analyses, revealed that elevated NPRC levels stabilized the C/EBPβ protein, leading to excessive lipid accumulation. The DNA-binding domain (DBD) of C/EBPβ interacted with the deubiquitinase USP30, a key regulator that inhibited K149-specific K48-linked polyubiquitination of C/EBPβ. Importantly, the ANPR region of NPRC bound to USP30, facilitating the deubiquitination of C/EBPβ. Furthermore, virtual screening identified punicalin, a natural compound, as a potential inhibitor of NPRC expression, which may reduce hepatic lipid accumulation, inflammation and fibrosis.</div></div><div><h3>Conclusions</h3><div>Our findings indicate that NPRC recruits USP30 to mediate the deubiquitination of C/EBPβ, driving lipid metabolism reprogramming. Targeting NPRC could represent a promising therapeutic approach for MAFLD.</div></div>","PeriodicalId":18694,"journal":{"name":"Metabolism: clinical and experimental","volume":"162 ","pages":"Article 156050"},"PeriodicalIF":10.8,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142470017","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-11DOI: 10.1016/j.metabol.2024.156047
Michail Kokkorakis, Pytrik Folkertsma, José Castela Forte, Bruce H R Wolffenbuttel, Sipko van Dam, Christos S Mantzoros
Background & aims: Noninvasive tools (NITs) are currently used to stratify the risk of having or developing hepatic steatosis or fibrosis. Their performance and a proteomic-enabled improvement in forecasting long-term cardio-renal-metabolic morbidity, malignancies, as well as cause-specific and all-cause mortality, are lacking. Therefore, the performance of established NITs needs to be investigated in identifying cardio-renal-metabolic morbidity, malignancies, cause-specific and overall mortality and improve their performance with novel, proteomic-enabled NITs, including growth differentiation factor 15 (GDF-15), allowing multipurpose utilization.
Methods: 502,359 UK Biobank participants free of the study outcomes at baseline with a 14-year median follow-up were grouped into three categories: a) general population, b) potentially metabolic dysfunction-associated steatotic liver disease (MASLD) population, c) individuals with type 2 diabetes mellitus. The investigated NITs include Aspartate aminotransferase to Platelet Ratio Index (APRI), Fibrosis 4 Index (FIB-4), Fatty Liver Index (FLI), Hepatic Steatosis Index (HSI), Lipid Accumulation Product (LAP), and metabolic dysfunction-associated fibrosis (MAF-5) score.
Results: Adding GDF-15 to the existing NITs led to significantly increased prognostic performance compared to the traditional NITs in almost all instances, reaching substantially high C-indices, ranging between 0.601 and 0.808, with an overall >0.2 improvement in C-index. Overall, with the GDF-15 enhanced NITs, up to more than seven times fewer individuals need to be screened to identify more incident cases of adverse outcomes compared to the traditional NITs. The cumulative incidence of all outcomes, based on the continuous value percentiles of NITs, is increasing exponentially in the upper quintile of the GDF-15 enhanced NITs.
Conclusions: The herein-developed GDF-15 enhanced indices demonstrate higher screening effectiveness and significantly improved prognostic abilities, which are reduced to practice through an easy-to-use web-based calculator tool (https://clinicalpredictor.shinyapps.io/multimorbidity-mortality-risk/).
{"title":"GDF-15 improves the predictive capacity of Steatotic liver disease non-invasive tests for incident morbidity and mortality risk for cardio-renal-metabolic diseases and malignancies.","authors":"Michail Kokkorakis, Pytrik Folkertsma, José Castela Forte, Bruce H R Wolffenbuttel, Sipko van Dam, Christos S Mantzoros","doi":"10.1016/j.metabol.2024.156047","DOIUrl":"https://doi.org/10.1016/j.metabol.2024.156047","url":null,"abstract":"<p><strong>Background & aims: </strong>Noninvasive tools (NITs) are currently used to stratify the risk of having or developing hepatic steatosis or fibrosis. Their performance and a proteomic-enabled improvement in forecasting long-term cardio-renal-metabolic morbidity, malignancies, as well as cause-specific and all-cause mortality, are lacking. Therefore, the performance of established NITs needs to be investigated in identifying cardio-renal-metabolic morbidity, malignancies, cause-specific and overall mortality and improve their performance with novel, proteomic-enabled NITs, including growth differentiation factor 15 (GDF-15), allowing multipurpose utilization.</p><p><strong>Methods: </strong>502,359 UK Biobank participants free of the study outcomes at baseline with a 14-year median follow-up were grouped into three categories: a) general population, b) potentially metabolic dysfunction-associated steatotic liver disease (MASLD) population, c) individuals with type 2 diabetes mellitus. The investigated NITs include Aspartate aminotransferase to Platelet Ratio Index (APRI), Fibrosis 4 Index (FIB-4), Fatty Liver Index (FLI), Hepatic Steatosis Index (HSI), Lipid Accumulation Product (LAP), and metabolic dysfunction-associated fibrosis (MAF-5) score.</p><p><strong>Results: </strong>Adding GDF-15 to the existing NITs led to significantly increased prognostic performance compared to the traditional NITs in almost all instances, reaching substantially high C-indices, ranging between 0.601 and 0.808, with an overall >0.2 improvement in C-index. Overall, with the GDF-15 enhanced NITs, up to more than seven times fewer individuals need to be screened to identify more incident cases of adverse outcomes compared to the traditional NITs. The cumulative incidence of all outcomes, based on the continuous value percentiles of NITs, is increasing exponentially in the upper quintile of the GDF-15 enhanced NITs.</p><p><strong>Conclusions: </strong>The herein-developed GDF-15 enhanced indices demonstrate higher screening effectiveness and significantly improved prognostic abilities, which are reduced to practice through an easy-to-use web-based calculator tool (https://clinicalpredictor.shinyapps.io/multimorbidity-mortality-risk/).</p>","PeriodicalId":18694,"journal":{"name":"Metabolism: clinical and experimental","volume":" ","pages":"156047"},"PeriodicalIF":10.8,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142470016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-10DOI: 10.1016/j.metabol.2024.156045
Joan Serrano, Saki Kondo, Grace M Link, Ian S Brown, Richard E Pratley, Kedryn K Baskin, Bret H Goodpaster, Paul M Coen, George A Kyriazis
Background: The TAS1R2 receptor, known for its role in taste perception, has also emerged as a key regulator of muscle physiology. Previous studies have shown that genetic ablation of TAS1R2 in mice enhances muscle fitness mimicking responses to endurance exercise training. However, the translational relevance of these findings to humans remains uncertain.
Methods: We explored responses to endurance exercise training in mice and humans with genetic deficiency of TAS1R2. First, we assessed the effects of muscle-specific deletion of TAS1R2 in mice (mKO) or wild type controls (mWT) following 4 weeks of voluntary wheel running (VWR). Next, we investigated the effects of the TAS1R2-Ile191Val (rs35874116) partial loss-of-function variant on responses to a 6-month diet-induced weight loss with exercise training (WLEX), weight loss alone (WL), or education control (CON) interventions in older individuals with obesity. Participants were retrospectively genotyped for the TAS1R2-Ile191Val polymorphism and classified as conventional function (Ile/Ile) or partial loss-of-function (Val carriers: Ile/Val and Val/Val). Body composition, cardiorespiratory fitness, and skeletal muscle mitochondrial function were assessed before and after the intervention.
Results: In response to VWR, mKO mice demonstrated enhanced running endurance and mitochondrial protein content. Similarly, TAS1R2 Val carriers exhibited distinctive improvements in body composition, including increased muscle mass, along with enhanced cardiorespiratory fitness and mitochondrial function in skeletal muscle following the WLEX intervention compared to Ile/Ile counterparts. Notably, every Val carrier demonstrated substantial responses to exercise training and weight loss, surpassing all Ile/Ile participants in overall performance metrics.
Conclusions: Our findings suggest that TAS1R2 partial loss-of-function confers beneficial effects on muscle function and metabolism in humans in response to exercise training, akin to observations in TAS1R2 muscle-deficient mice. Targeting TAS1R2 may help enhancing exercise training adaptations in individuals with compromised exercise tolerance or metabolic disorders, presenting a potential avenue for personalized exercise interventions.
{"title":"A partial loss-of-function variant (Ile191Val) of the TAS1R2 glucose receptor is associated with enhanced responses to exercise training in older adults with obesity: A translational study.","authors":"Joan Serrano, Saki Kondo, Grace M Link, Ian S Brown, Richard E Pratley, Kedryn K Baskin, Bret H Goodpaster, Paul M Coen, George A Kyriazis","doi":"10.1016/j.metabol.2024.156045","DOIUrl":"10.1016/j.metabol.2024.156045","url":null,"abstract":"<p><strong>Background: </strong>The TAS1R2 receptor, known for its role in taste perception, has also emerged as a key regulator of muscle physiology. Previous studies have shown that genetic ablation of TAS1R2 in mice enhances muscle fitness mimicking responses to endurance exercise training. However, the translational relevance of these findings to humans remains uncertain.</p><p><strong>Methods: </strong>We explored responses to endurance exercise training in mice and humans with genetic deficiency of TAS1R2. First, we assessed the effects of muscle-specific deletion of TAS1R2 in mice (mKO) or wild type controls (mWT) following 4 weeks of voluntary wheel running (VWR). Next, we investigated the effects of the TAS1R2<sup>-Ile191Val</sup> (rs35874116) partial loss-of-function variant on responses to a 6-month diet-induced weight loss with exercise training (WLEX), weight loss alone (WL), or education control (CON) interventions in older individuals with obesity. Participants were retrospectively genotyped for the TAS1R2<sup>-Ile191Val</sup> polymorphism and classified as conventional function (Ile/Ile) or partial loss-of-function (Val carriers: Ile/Val and Val/Val). Body composition, cardiorespiratory fitness, and skeletal muscle mitochondrial function were assessed before and after the intervention.</p><p><strong>Results: </strong>In response to VWR, mKO mice demonstrated enhanced running endurance and mitochondrial protein content. Similarly, TAS1R2 Val carriers exhibited distinctive improvements in body composition, including increased muscle mass, along with enhanced cardiorespiratory fitness and mitochondrial function in skeletal muscle following the WLEX intervention compared to Ile/Ile counterparts. Notably, every Val carrier demonstrated substantial responses to exercise training and weight loss, surpassing all Ile/Ile participants in overall performance metrics.</p><p><strong>Conclusions: </strong>Our findings suggest that TAS1R2 partial loss-of-function confers beneficial effects on muscle function and metabolism in humans in response to exercise training, akin to observations in TAS1R2 muscle-deficient mice. Targeting TAS1R2 may help enhancing exercise training adaptations in individuals with compromised exercise tolerance or metabolic disorders, presenting a potential avenue for personalized exercise interventions.</p>","PeriodicalId":18694,"journal":{"name":"Metabolism: clinical and experimental","volume":" ","pages":"156045"},"PeriodicalIF":10.8,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142406618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Background & aims: Nucleobindin-2 (NUCB2)/nesfatin-1, a signal with recognized anorexigenic and insulin-sensitizing properties in peripheral tissues, is expressed within the hypothalamus. However, the potential involvement of central nesfatin-1 signaling in the pathophysiology of hepatic steatosis remains unknown. This study aimed to determine whether and how central NUCB2/nesfatin-1 plays a role in liver steatosis.
Methods: We generated Nucb2 knockout (Nucb2-/-) rats and administered continuous intracerebroventricular (ICV) nesfatin-1 infusion, while observing its effect on liver steatosis. The molecular mechanism of action of nesfatin-1 was elucidated via proteomics, phosphoproteomics and molecular biology methods.
Results: Herein, we present compelling evidence indicating diminished NUCB2 expression in the hypothalamus of obese rodents. We demonstrated that chronic ICV infusion of nesfatin-1 mitigated both diet-induced obesity and liver steatosis in high-fat diet (HFD)-fed Nucb2-/- rats by regulating hypothalamic endoplasmic reticulum (ER) stress and Akt phosphorylation. Furthermore, we revealed that the increase in hypothalamic insulin resistance (IR) and ER stress induced by tunicamycin infusion or Ero1α overexpression exacerbated hepatic steatosis and offset the favorable influence of central nesfatin-1 on hepatic steatosis. The metabolic action of central nesfatin-1 is contingent upon vagal nerve transmission to the liver. Mechanistically, nesfatin-1 impedes ER stress and interacts with Ero1α to repress its Ser106 phosphorylation. This leads to the enhancement of Akt activity in the hypothalamus, culminating in the inhibition of hepatic lipogenesis.
Conclusions: These findings underscore the importance of hypothalamic NUCB2/nesfatin-1 as a key mediator in the top-down neural mechanism that combats diet-induced liver steatosis.
{"title":"Central NUCB2/nesfatin-1 signaling ameliorates liver steatosis through suppression of endoplasmic reticulum stress in the hypothalamus.","authors":"Yirui He, Cheng Zhang, Shaobo Wu, Ke Li, Siliang Zhang, Mingyuan Tian, Chen Chen, Dongfang Liu, Gangyi Yang, Ling Li, Mengliu Yang","doi":"10.1016/j.metabol.2024.156046","DOIUrl":"10.1016/j.metabol.2024.156046","url":null,"abstract":"<p><strong>Background & aims: </strong>Nucleobindin-2 (NUCB2)/nesfatin-1, a signal with recognized anorexigenic and insulin-sensitizing properties in peripheral tissues, is expressed within the hypothalamus. However, the potential involvement of central nesfatin-1 signaling in the pathophysiology of hepatic steatosis remains unknown. This study aimed to determine whether and how central NUCB2/nesfatin-1 plays a role in liver steatosis.</p><p><strong>Methods: </strong>We generated Nucb2 knockout (Nucb2<sup>-/-</sup>) rats and administered continuous intracerebroventricular (ICV) nesfatin-1 infusion, while observing its effect on liver steatosis. The molecular mechanism of action of nesfatin-1 was elucidated via proteomics, phosphoproteomics and molecular biology methods.</p><p><strong>Results: </strong>Herein, we present compelling evidence indicating diminished NUCB2 expression in the hypothalamus of obese rodents. We demonstrated that chronic ICV infusion of nesfatin-1 mitigated both diet-induced obesity and liver steatosis in high-fat diet (HFD)-fed Nucb2<sup>-/-</sup> rats by regulating hypothalamic endoplasmic reticulum (ER) stress and Akt phosphorylation. Furthermore, we revealed that the increase in hypothalamic insulin resistance (IR) and ER stress induced by tunicamycin infusion or Ero1α overexpression exacerbated hepatic steatosis and offset the favorable influence of central nesfatin-1 on hepatic steatosis. The metabolic action of central nesfatin-1 is contingent upon vagal nerve transmission to the liver. Mechanistically, nesfatin-1 impedes ER stress and interacts with Ero1α to repress its Ser106 phosphorylation. This leads to the enhancement of Akt activity in the hypothalamus, culminating in the inhibition of hepatic lipogenesis.</p><p><strong>Conclusions: </strong>These findings underscore the importance of hypothalamic NUCB2/nesfatin-1 as a key mediator in the top-down neural mechanism that combats diet-induced liver steatosis.</p>","PeriodicalId":18694,"journal":{"name":"Metabolism: clinical and experimental","volume":" ","pages":"156046"},"PeriodicalIF":10.8,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142400753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
<p><strong>Background: </strong>Metabolic reprogramming is a hallmark of cancer, characterized by a high dependence on glycolysis and an enhanced utilization of acetate as an alternative carbon source. ACSS2 is a critical regulator of acetate metabolism, playing a significant role in the development and progression of various malignancies. ACSS2 facilitates the conversion of acetate to acetyl-CoA, which participates in multiple metabolic pathways and functions as an epigenetic regulator of protein acetylation, thereby modulating key cellular processes such as autophagy. However, the roles and intrinsic connections of ACSS2, glycolysis, protein acetylation, and autophagy in ovarian cancer (OC) remain to be elucidated.</p><p><strong>Basic procedures: </strong>Utilizing clinical specimens and online databases, we analysed the expression of ACSS2 in OC and its relationship with clinical prognosis. By knocking down ACSS2, we evaluated its effects on the malignant phenotype, acetate metabolism, glycolysis, and autophagy. The metabolic alterations in OC cells were comprehensively analysed using Seahorse assays, transmission electron microscopy, membrane potential measurements, and stable-isotope labeling techniques. CUT&TAG and co-immunoprecipitation techniques were employed to explore the deacetylation of autophagy-related proteins mediated by ACSS2 via SIRT1. Additionally, through molecular docking, transcriptome sequencing, and metabolomics analyses, we validated the pharmacological effects of paeonol on ACSS2 and the glycolytic process in OC cells. Finally, both in vitro and in vivo experiments were performed to investigate the impact of paeonol on autophagy and its anti-OC effects mediated through the ACSS2/SIRT1 deacetylation axis.</p><p><strong>Main findings: </strong>ACSS2 is significantly upregulated in OC and is associated with poor prognosis. Knockdown of ACSS2 inhibits OC cells proliferation, migration, invasion, angiogenesis, and platinum resistance, while reducing tumour burden in vivo. Mechanistically, inhibiting ACSS2 reduces acetate metabolism and suppresses glycolysis by targeting HXK2. This glycolytic reduction promotes the translocation of ACSS2 from the cytoplasm to the nucleus, leading to increased expression of the deacetylase SIRT1. SIRT1 mediates the deacetylation of autophagy-related proteins, such as ATG5 and ATG2B, thereby significantly activating autophagy in OC cells and exerting antitumor effects. Paeonol inhibits acetate metabolism and glycolysis in OC cells by targeting ACSS2. Paeonol activates autophagy through the ACSS2/SIRT1/ATG5/ATG2B deacetylation axis, demonstrating inhibition of OC in vitro and in vivo.</p><p><strong>Principal conclusions: </strong>Pae can serve as an effective, low-toxicity, multi-targeted drug targeting ACSS2 and glycolysis. It activates autophagy through the ACSS2/SIRT1/ATG5/ATG2B deacetylation signalling cascade, thereby exerting anti-OC effects. Our study provides new insights into the malign
{"title":"Inhibition of ACSS2 triggers glycolysis inhibition and nuclear translocation to activate SIRT1/ATG5/ATG2B deacetylation axis, promoting autophagy and reducing malignancy and chemoresistance in ovarian cancer.","authors":"Jiang Yang, Haoyu Wang, Bingshu Li, Jingchun Liu, Xiaoyi Zhang, Ying Wang, Jiaxin Peng, Likun Gao, Xinqi Wang, Siyuan Hu, Wenyi Zhang, Li Hong","doi":"10.1016/j.metabol.2024.156041","DOIUrl":"10.1016/j.metabol.2024.156041","url":null,"abstract":"<p><strong>Background: </strong>Metabolic reprogramming is a hallmark of cancer, characterized by a high dependence on glycolysis and an enhanced utilization of acetate as an alternative carbon source. ACSS2 is a critical regulator of acetate metabolism, playing a significant role in the development and progression of various malignancies. ACSS2 facilitates the conversion of acetate to acetyl-CoA, which participates in multiple metabolic pathways and functions as an epigenetic regulator of protein acetylation, thereby modulating key cellular processes such as autophagy. However, the roles and intrinsic connections of ACSS2, glycolysis, protein acetylation, and autophagy in ovarian cancer (OC) remain to be elucidated.</p><p><strong>Basic procedures: </strong>Utilizing clinical specimens and online databases, we analysed the expression of ACSS2 in OC and its relationship with clinical prognosis. By knocking down ACSS2, we evaluated its effects on the malignant phenotype, acetate metabolism, glycolysis, and autophagy. The metabolic alterations in OC cells were comprehensively analysed using Seahorse assays, transmission electron microscopy, membrane potential measurements, and stable-isotope labeling techniques. CUT&TAG and co-immunoprecipitation techniques were employed to explore the deacetylation of autophagy-related proteins mediated by ACSS2 via SIRT1. Additionally, through molecular docking, transcriptome sequencing, and metabolomics analyses, we validated the pharmacological effects of paeonol on ACSS2 and the glycolytic process in OC cells. Finally, both in vitro and in vivo experiments were performed to investigate the impact of paeonol on autophagy and its anti-OC effects mediated through the ACSS2/SIRT1 deacetylation axis.</p><p><strong>Main findings: </strong>ACSS2 is significantly upregulated in OC and is associated with poor prognosis. Knockdown of ACSS2 inhibits OC cells proliferation, migration, invasion, angiogenesis, and platinum resistance, while reducing tumour burden in vivo. Mechanistically, inhibiting ACSS2 reduces acetate metabolism and suppresses glycolysis by targeting HXK2. This glycolytic reduction promotes the translocation of ACSS2 from the cytoplasm to the nucleus, leading to increased expression of the deacetylase SIRT1. SIRT1 mediates the deacetylation of autophagy-related proteins, such as ATG5 and ATG2B, thereby significantly activating autophagy in OC cells and exerting antitumor effects. Paeonol inhibits acetate metabolism and glycolysis in OC cells by targeting ACSS2. Paeonol activates autophagy through the ACSS2/SIRT1/ATG5/ATG2B deacetylation axis, demonstrating inhibition of OC in vitro and in vivo.</p><p><strong>Principal conclusions: </strong>Pae can serve as an effective, low-toxicity, multi-targeted drug targeting ACSS2 and glycolysis. It activates autophagy through the ACSS2/SIRT1/ATG5/ATG2B deacetylation signalling cascade, thereby exerting anti-OC effects. Our study provides new insights into the malign","PeriodicalId":18694,"journal":{"name":"Metabolism: clinical and experimental","volume":" ","pages":"156041"},"PeriodicalIF":10.8,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142372342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.metabol.2024.156042
Dandan Wang, Tianjiao Wei, Xiaona Cui, Li Xia, Yafei Jiang, Deshan Yin, Xinyue Liao, Fei Li, Jian Li, Qi Wu, Xiafang Lin, Shan Lang, Yunyi Le, Jichun Yang, Jin Yang, Rui Wei, Tianpei Hong
<p><strong>Background: </strong>Fam3a has been demonstrated to regulate pancreatic β-cell function and glucose homeostasis. However, the role and mechanism of Fam3a in regulating α-cell function remain unexplored.</p><p><strong>Methods: </strong>Glucagon and glucagon-like peptide-1 (GLP-1) levels in pancreas and plasma were measured in global Fam3a knockout (Fam3a<sup>-/-</sup>) mice. Human islet single-cell RNA sequencing (scRNA-seq) datasets were utilized to analyze gene expression correlations between FAM3A and PCSK1 (encoding PC1/3, which processes proglucagon into GLP-1). Mouse pancreatic α-cell line αTC1.9 cells were transfected with Fam3a siRNA or plasmid for Fam3a knockdown or overexpression to explore the effects of Fam3a on PC1/3 expression and GLP-1 production. The downstream mediator (including Nr4a2) was identified by transcriptomic analysis, and its role was confirmed by Fam3a knockdown or overexpression in αTC1.9 cells. Based on the interacted protein of Nr4a2 and the direct binding to Pcsk1 promoter, the transcription factor Foxa2 was selected for further verification. Nuclear translocation assay and dual-luciferase reporter assay were used to clarify the involvement of Fam3a-Nr4a2-Foxa2 pathway in PC1/3 expression and GLP-1 production. Moreover, α-cell-specific Fam3a knockout (Fam3a<sup>α-/-</sup>) mice were constructed to evaluate the metabolic variables and hormone levels under normoglycemic, high-fat diet (HFD)-fed and streptozotocin (STZ)-induced diabetic conditions. Exendin 9-39 (Ex9), a GLP-1 receptor antagonist, was used to investigate GLP-1 paracrine effects in Fam3a<sup>α-/-</sup> mice and in their primary islets.</p><p><strong>Results: </strong>Compared with wild-type mice, pancreatic and plasma active GLP-1 levels were increased in Fam3a<sup>-/-</sup> mice. Analysis of human islet scRNA-seq datasets showed a significant negative correction between FAM3A and PCSK1 in α-cells. Fam3a knockdown upregulated PC1/3 expression and GLP-1 production in αTC1.9 cells, while Fam3a overexpression displayed inverse effects. Transcriptomic analysis identified Nr4a2 as a key downstream mediator of Fam3a, and Nr4a2 expression in αTC1.9 cells was downregulated and upregulated by Fam3a knockdown and overexpression, respectively. Nr4a2 silencing increased PC1/3 expression, albeit Nr4a2 did not directly bind to Pcsk1 promoter. Instead, Nr4a2 formed a complex with Foxa2 to facilitate Fam3a-mediated Foxa2 nuclear translocation. Foxa2 negatively regulated PC1/3 expression and GLP-1 production. Besides, Foxa2 inhibited the transcriptional activity of Pcsk1 promoter at specific binding sites 10 and 6, and this inhibition was intensified by Nr4a2 in αTC1.9 cells. Compared with Flox/cre littermates, improved glucose tolerance, increased active GLP-1 level in pancreas and plasma, upregulated plasma insulin level in response to glucose, and decreased plasma glucagon level were observed in Fam3a<sup>α-/-</sup> mice. Primary islets isolated from Fam3a
{"title":"Fam3a-mediated prohormone convertase switch in α-cells regulates pancreatic GLP-1 production in an Nr4a2-Foxa2-dependent manner.","authors":"Dandan Wang, Tianjiao Wei, Xiaona Cui, Li Xia, Yafei Jiang, Deshan Yin, Xinyue Liao, Fei Li, Jian Li, Qi Wu, Xiafang Lin, Shan Lang, Yunyi Le, Jichun Yang, Jin Yang, Rui Wei, Tianpei Hong","doi":"10.1016/j.metabol.2024.156042","DOIUrl":"10.1016/j.metabol.2024.156042","url":null,"abstract":"<p><strong>Background: </strong>Fam3a has been demonstrated to regulate pancreatic β-cell function and glucose homeostasis. However, the role and mechanism of Fam3a in regulating α-cell function remain unexplored.</p><p><strong>Methods: </strong>Glucagon and glucagon-like peptide-1 (GLP-1) levels in pancreas and plasma were measured in global Fam3a knockout (Fam3a<sup>-/-</sup>) mice. Human islet single-cell RNA sequencing (scRNA-seq) datasets were utilized to analyze gene expression correlations between FAM3A and PCSK1 (encoding PC1/3, which processes proglucagon into GLP-1). Mouse pancreatic α-cell line αTC1.9 cells were transfected with Fam3a siRNA or plasmid for Fam3a knockdown or overexpression to explore the effects of Fam3a on PC1/3 expression and GLP-1 production. The downstream mediator (including Nr4a2) was identified by transcriptomic analysis, and its role was confirmed by Fam3a knockdown or overexpression in αTC1.9 cells. Based on the interacted protein of Nr4a2 and the direct binding to Pcsk1 promoter, the transcription factor Foxa2 was selected for further verification. Nuclear translocation assay and dual-luciferase reporter assay were used to clarify the involvement of Fam3a-Nr4a2-Foxa2 pathway in PC1/3 expression and GLP-1 production. Moreover, α-cell-specific Fam3a knockout (Fam3a<sup>α-/-</sup>) mice were constructed to evaluate the metabolic variables and hormone levels under normoglycemic, high-fat diet (HFD)-fed and streptozotocin (STZ)-induced diabetic conditions. Exendin 9-39 (Ex9), a GLP-1 receptor antagonist, was used to investigate GLP-1 paracrine effects in Fam3a<sup>α-/-</sup> mice and in their primary islets.</p><p><strong>Results: </strong>Compared with wild-type mice, pancreatic and plasma active GLP-1 levels were increased in Fam3a<sup>-/-</sup> mice. Analysis of human islet scRNA-seq datasets showed a significant negative correction between FAM3A and PCSK1 in α-cells. Fam3a knockdown upregulated PC1/3 expression and GLP-1 production in αTC1.9 cells, while Fam3a overexpression displayed inverse effects. Transcriptomic analysis identified Nr4a2 as a key downstream mediator of Fam3a, and Nr4a2 expression in αTC1.9 cells was downregulated and upregulated by Fam3a knockdown and overexpression, respectively. Nr4a2 silencing increased PC1/3 expression, albeit Nr4a2 did not directly bind to Pcsk1 promoter. Instead, Nr4a2 formed a complex with Foxa2 to facilitate Fam3a-mediated Foxa2 nuclear translocation. Foxa2 negatively regulated PC1/3 expression and GLP-1 production. Besides, Foxa2 inhibited the transcriptional activity of Pcsk1 promoter at specific binding sites 10 and 6, and this inhibition was intensified by Nr4a2 in αTC1.9 cells. Compared with Flox/cre littermates, improved glucose tolerance, increased active GLP-1 level in pancreas and plasma, upregulated plasma insulin level in response to glucose, and decreased plasma glucagon level were observed in Fam3a<sup>α-/-</sup> mice. Primary islets isolated from Fam3a","PeriodicalId":18694,"journal":{"name":"Metabolism: clinical and experimental","volume":" ","pages":"156042"},"PeriodicalIF":10.8,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142372341","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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