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Freeburg SH, Shwartz A, Kemény LV, Smith CJ, Weeks O, Miller BM, PenkoffLidbeck N, Fisher DE, Evason KJ, Goessling W. Hepatocyte vitamin D receptor functions as a nutrient sensor that regulates energy storage and tissue growth in zebrafish. Cell Rep 2024; 43:114393. [PMID: 38944835 DOI: 10.1016/j.celrep.2024.114393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 03/20/2024] [Accepted: 06/07/2024] [Indexed: 07/02/2024] Open
Abstract
Vitamin D receptor (VDR) has been implicated in fatty liver pathogenesis, but its role in the regulation of organismal energy usage remains unclear. Here, we illuminate the evolutionary function of VDR by demonstrating that zebrafish Vdr coordinates hepatic and organismal energy homeostasis through antagonistic regulation of nutrient storage and tissue growth. Hepatocyte-specific Vdr impairment increases hepatic lipid storage, partially through acsl4a induction, while simultaneously diminishing fatty acid oxidation and liver growth. Importantly, Vdr impairment exacerbates the starvation-induced hepatic storage of systemic fatty acids, indicating that loss of Vdr signaling elicits hepatocellular energy deficiency. Strikingly, hepatocyte Vdr impairment diminishes diet-induced systemic growth while increasing hepatic and visceral fat in adult fish, revealing that hepatic Vdr signaling is required for complete adaptation to food availability. These data establish hepatocyte Vdr as a regulator of organismal energy expenditure and define an evolutionary function for VDR as a transcriptional effector of environmental nutrient supply.
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Affiliation(s)
- Scott H Freeburg
- Division of Genetics, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Arkadi Shwartz
- Division of Genetics, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Lajos V Kemény
- Cutaneous Biology Research Center, Department of Dermatology and Cancer Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; HCEMM-SU Translational Dermatology Research Group, Department of Physiology, Semmelweis University, 1085 Budapest Hungary; Department of Dermatology, Venereology, and Dermatooncology, Semmelweis University, 1085 Budapest Hungary
| | - Colton J Smith
- Division of Genetics, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Olivia Weeks
- Division of Genetics, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Bess M Miller
- Division of Genetics, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Nadia PenkoffLidbeck
- Division of Genetics, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - David E Fisher
- Cutaneous Biology Research Center, Department of Dermatology and Cancer Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Kimberley J Evason
- Huntsman Cancer Institute and Department of Pathology, University of Utah, Salt Lake City, UT 84112, USA
| | - Wolfram Goessling
- Division of Genetics, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; Harvard Stem Cell Institute, Cambridge, MA 02138, USA; Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Harvard-MIT Division of Health Sciences and Technology, Boston, MA 02115, USA; Division of Gastroenterology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
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2
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Pečenková T, Potocký M, Stegmann M. More than meets the eye: knowns and unknowns of the trafficking of small secreted proteins in Arabidopsis. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:3713-3730. [PMID: 38693754 DOI: 10.1093/jxb/erae172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Accepted: 05/01/2024] [Indexed: 05/03/2024]
Abstract
Small proteins represent a significant portion of the cargo transported through plant secretory pathways, playing crucial roles in developmental processes, fertilization, and responses to environmental stresses. Despite the importance of small secreted proteins, substantial knowledge gaps persist regarding the regulatory mechanisms governing their trafficking along the secretory pathway, and their ultimate localization or destination. To address these gaps, we conducted a comprehensive literature review, focusing particularly on trafficking and localization of Arabidopsis small secreted proteins with potential biochemical and/or signaling roles in the extracellular space, typically those within the size range of 101-200 amino acids. Our investigation reveals that while at least six members of the 21 mentioned families have a confirmed extracellular localization, eight exhibit intracellular localization, including cytoplasmic, nuclear, and chloroplastic locations, despite the presence of N-terminal signal peptides. Further investigation into the trafficking and secretion mechanisms of small protein cargo could not only deepen our understanding of plant cell biology and physiology but also provide a foundation for genetic manipulation strategies leading to more efficient plant cultivation.
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Affiliation(s)
- Tamara Pečenková
- Institute of Experimental Botany of the Czech Academy of Sciences, Rozvojová 263, 165 02, Prague 6, Czech Republic
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, 128 44, Prague 2, Czech Republic
| | - Martin Potocký
- Institute of Experimental Botany of the Czech Academy of Sciences, Rozvojová 263, 165 02, Prague 6, Czech Republic
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, 128 44, Prague 2, Czech Republic
| | - Martin Stegmann
- Technical University Munich, School of Life Sciences, Phytopathology, Emil-Ramann-Str. 2, 85354 Freising, Germany
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Jacovetti C, Donnelly C, Menoud V, Suleiman M, Cosentino C, Sobel J, Wu K, Bouzakri K, Marchetti P, Guay C, Kayser B, Regazzi R. The mitochondrial tRNA-derived fragment, mt-tRF-Leu TAA, couples mitochondrial metabolism to insulin secretion. Mol Metab 2024; 84:101955. [PMID: 38704026 PMCID: PMC11112368 DOI: 10.1016/j.molmet.2024.101955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 04/29/2024] [Accepted: 04/29/2024] [Indexed: 05/06/2024] Open
Abstract
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.
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Affiliation(s)
- Cecile Jacovetti
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland.
| | - Chris Donnelly
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Véronique Menoud
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Mara Suleiman
- Department of Clinical and Experimental Medicine, Diabetes Unit, University of Pisa, Pisa, Italy
| | - Cristina Cosentino
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Jonathan Sobel
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Kejing Wu
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Karim Bouzakri
- UMR DIATHEC, EA 7294, Centre Européen d'Etude du Diabète, Université de Strasbourg, Fédération de Médecine Translationnelle de Strasbourg, Strasbourg, France
| | - Piero Marchetti
- Department of Clinical and Experimental Medicine, Diabetes Unit, University of Pisa, Pisa, Italy
| | - Claudiane Guay
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Bengt Kayser
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Romano Regazzi
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland; Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
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Boyer CK, Blom SE, Machado AE, Rohli KE, Maxson ME, Stephens SB. Loss of the Golgi-localized v-ATPase subunit does not alter insulin granule formation or pancreatic islet β-cell function. Am J Physiol Endocrinol Metab 2024; 326:E245-E257. [PMID: 38265287 PMCID: PMC11193524 DOI: 10.1152/ajpendo.00342.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 01/11/2024] [Accepted: 01/11/2024] [Indexed: 01/25/2024]
Abstract
Delayed Golgi export of proinsulin has recently been identified as an underlying mechanism leading to insulin granule loss and β-cell secretory defects in type 2 diabetes (T2D). Because acidification of the Golgi lumen is critical for proinsulin sorting and delivery into the budding secretory granule, we reasoned that dysregulation of Golgi pH may contribute to proinsulin trafficking defects. In this report, we examined pH regulation of the Golgi and identified a partial alkalinization of the Golgi lumen in a diabetes model. To further explore this, we generated a β-cell specific knockout (KO) of the v0a2 subunit of the v-ATPase pump, which anchors the v-ATPase to the Golgi membrane. Although loss of v0a2 partially neutralized Golgi pH and was accompanied by distension of the Golgi cisternae, proinsulin export from the Golgi and insulin granule formation were not affected. Furthermore, β-cell function was well preserved. β-cell v0a2 KO mice exhibited normal glucose tolerance in both sexes, no genotypic difference to diet-induced obesity, and normal insulin secretory responses. Collectively, our data demonstrate the v0a2 subunit contributes to β-cell Golgi pH regulation but suggest that additional disturbances to Golgi structure and function contribute to proinsulin trafficking defects in diabetes.NEW & NOTEWORTHY Delayed proinsulin export from the Golgi in diabetic β-cells contributes to decreased insulin granule formation, but the underlying mechanisms are not clear. Here, we explored if dysregulation of Golgi pH can alter Golgi function using β-cell specific knockout (KO) of the Golgi-localized subunit of the v-ATPase, v0a2. We show that partial alkalinization of the Golgi dilates the cisternae, but does not affect proinsulin export, insulin granule formation, insulin secretion, or glucose homeostasis.
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Affiliation(s)
- Cierra K Boyer
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, Iowa, United States
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, United States
| | - Sandra E Blom
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, United States
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States
| | - Ashleigh E Machado
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, United States
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States
| | - Kristen E Rohli
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, United States
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States
- Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa City, Iowa, United States
| | - Michelle E Maxson
- Program in Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Samuel B Stephens
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, United States
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States
- Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa City, Iowa, United States
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Pasquier A, Pastore N, D'Orsi L, Colonna R, Esposito A, Maffia V, De Cegli R, Mutarelli M, Ambrosio S, Tufano G, Grimaldi A, Cesana M, Cacchiarelli D, Delalleau N, Napolitano G, Ballabio A. TFEB and TFE3 control glucose homeostasis by regulating insulin gene expression. EMBO J 2023; 42:e113928. [PMID: 37712288 PMCID: PMC10620765 DOI: 10.15252/embj.2023113928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 07/31/2023] [Accepted: 08/25/2023] [Indexed: 09/16/2023] Open
Abstract
To fulfill their function, pancreatic beta cells require precise nutrient-sensing mechanisms that control insulin production. Transcription factor EB (TFEB) and its homolog TFE3 have emerged as crucial regulators of the adaptive response of cell metabolism to environmental cues. Here, we show that TFEB and TFE3 regulate beta-cell function and insulin gene expression in response to variations in nutrient availability. We found that nutrient deprivation in beta cells promoted TFEB/TFE3 activation, which resulted in suppression of insulin gene expression. TFEB overexpression was sufficient to inhibit insulin transcription, whereas beta cells depleted of both TFEB and TFE3 failed to suppress insulin gene expression in response to amino acid deprivation. Interestingly, ChIP-seq analysis showed binding of TFEB to super-enhancer regions that regulate insulin transcription. Conditional, beta-cell-specific, Tfeb-overexpressing, and Tfeb/Tfe3 double-KO mice showed severe alteration of insulin transcription, secretion, and glucose tolerance, indicating that TFEB and TFE3 are important physiological mediators of pancreatic function. Our findings reveal a nutrient-controlled transcriptional mechanism that regulates insulin production, thus playing a key role in glucose homeostasis at both cellular and organismal levels.
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Affiliation(s)
- Adrien Pasquier
- Telethon Institute of Genetics and Medicine (TIGEM)NaplesItaly
| | - Nunzia Pastore
- Telethon Institute of Genetics and Medicine (TIGEM)NaplesItaly
- Medical Genetics Unit, Department of Medical and Translational ScienceFederico II UniversityNaplesItaly
| | - Luca D'Orsi
- Telethon Institute of Genetics and Medicine (TIGEM)NaplesItaly
| | - Rita Colonna
- Telethon Institute of Genetics and Medicine (TIGEM)NaplesItaly
| | | | - Veronica Maffia
- Telethon Institute of Genetics and Medicine (TIGEM)NaplesItaly
| | | | - Margherita Mutarelli
- Institute of Applied Sciences and Intelligent SystemsNational Research Council (ISASI‐CNR)PozzuoliItaly
| | | | - Gennaro Tufano
- Telethon Institute of Genetics and Medicine (TIGEM)NaplesItaly
| | | | - Marcella Cesana
- Telethon Institute of Genetics and Medicine (TIGEM)NaplesItaly
| | - Davide Cacchiarelli
- Telethon Institute of Genetics and Medicine (TIGEM)NaplesItaly
- Medical Genetics Unit, Department of Medical and Translational ScienceFederico II UniversityNaplesItaly
- School for Advanced Studies, Genomics and Experimental Medicine ProgramUniversity of Naples "Federico II"NaplesItaly
| | | | - Gennaro Napolitano
- Telethon Institute of Genetics and Medicine (TIGEM)NaplesItaly
- Medical Genetics Unit, Department of Medical and Translational ScienceFederico II UniversityNaplesItaly
- School for Advanced Studies, Genomics and Experimental Medicine ProgramUniversity of Naples "Federico II"NaplesItaly
| | - Andrea Ballabio
- Telethon Institute of Genetics and Medicine (TIGEM)NaplesItaly
- Medical Genetics Unit, Department of Medical and Translational ScienceFederico II UniversityNaplesItaly
- School for Advanced Studies, Genomics and Experimental Medicine ProgramUniversity of Naples "Federico II"NaplesItaly
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonTXUSA
- Jan and Dan Duncan Neurological Research InstituteTexas Children's HospitalHoustonTXUSA
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Kim JS, Kim HJ, Lee EB, Choi JH, Jung J, Jang HH, Park SY, Ha KC, Park YK, Joo JC, Lee SH. Supplementary Effects of Allium hookeri Extract on Glucose Tolerance in Prediabetic Subjects and C57BL/KsJ- db/db Mice. Pharmaceuticals (Basel) 2023; 16:1364. [PMID: 37895834 PMCID: PMC10610268 DOI: 10.3390/ph16101364] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 09/16/2023] [Accepted: 09/20/2023] [Indexed: 10/29/2023] Open
Abstract
Allium hookeri (AH) has been used as a nutritional and medicinal food in Asia for many years. Our previous studies have described its anti-diabetic, anti-obesity, and anti-inflammatory activities in animal models and prediabetes. This study investigated whether AH could improve glycemia by modulating insulin secretion in prediabetic subjects through an in-depth study. Eighty prediabetic subjects (100 ≤ fasting plasma glucose < 140 mg/dL) were randomly assigned to a placebo (n = 40) group or an ethanol AH extract (500 mg/day, n = 40) group for 12 weeks. Dietary intake and physical activity, blood glucose (an oral glucose tolerance test for 120 min), insulin (insulin response to oral glucose for 120 min), area under the curve (AUC) of glucose or insulin after oral glucose intake, insulin sensitivity markers, C-peptide, adiponectin, glycated hemoglobin A1c (HbA1c) levels, hematological tests (WBC, RBC, hemoglobin, hematocrit, and platelet count), blood biochemical parameters (ALP, AST, total bilirubin, total protein, albumin, gamma-GT, BUN, creatinine, LD, CK, and hs-CRP), and urine parameters (specific gravity and pH) were examined at both baseline and 12 weeks after supplementation with placebo or AH capsules. Fifty-eight participants (placebo group: 20 men and 10 women; AH group: 13 men and 15 women) completed the study. AH supplementation moderately reduced postprandial blood glucose at 60 min (-6.14 mg/dL, p = 0.061), postprandial insulin levels at 90 min (-16.69 µU/mL, p = 0.017), the glucose AUC at 90 min (-412.52 mg*min/dL, p = 0.021), as well as the insulin AUC at 90 min (-978.77 µU*min/mL, p = 0.021) and 120 min (-1426.41 µU*min/mL, p = 0.015) when compared with the placebo group. However, there were no effects of AH on dietary intake and physical activity; HOMA index; HbAlc; C-peptide; or adiponectin, hematological-, blood biochemical-, and urinary markers. To confirm the effects of AH extract on blood glucose insulin sensitivity, C57BL/6J or C57BL/KsJ-db/db mice were used (n = 8/group). Body weight, fasting plasma glucose level, lipid profiles, liver and renal function, pancreatic histology, and insulin immunoreactivity were assessed. In the diabetic db/db mice, hyperglycemia, which was accompanied by an increase in insulin secretion in diabetic mice, was significantly reduced by AH treatment, resulting in the alleviation of β-cell overcompensation and insulin resistance. We confirmed that AH supplementation can effectively control blood glucose and insulin levels by improving insulin sensitivity and may be a potential agent for glycemic control in subjects with prediabetes and type 2 diabetes mellitus.
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Affiliation(s)
- Ji-Su Kim
- Functional Food Division, Department of Agro-food Resources, National Institute of Agricultural Sciences, Rural Development Administration, Wanju 55365, Jeonbuk, Republic of Korea; (J.-S.K.); (E.-B.L.); (J.-H.C.); (J.J.); (H.-H.J.); (S.-Y.P.)
| | - Hyun-Ju Kim
- Kimchi Functionality Research Group, World Institute of Kimchi, Gwangju 61755, Jeolla, Republic of Korea;
| | - Eun-Byeol Lee
- Functional Food Division, Department of Agro-food Resources, National Institute of Agricultural Sciences, Rural Development Administration, Wanju 55365, Jeonbuk, Republic of Korea; (J.-S.K.); (E.-B.L.); (J.-H.C.); (J.J.); (H.-H.J.); (S.-Y.P.)
| | - Ji-Hye Choi
- Functional Food Division, Department of Agro-food Resources, National Institute of Agricultural Sciences, Rural Development Administration, Wanju 55365, Jeonbuk, Republic of Korea; (J.-S.K.); (E.-B.L.); (J.-H.C.); (J.J.); (H.-H.J.); (S.-Y.P.)
| | - Jieun Jung
- Functional Food Division, Department of Agro-food Resources, National Institute of Agricultural Sciences, Rural Development Administration, Wanju 55365, Jeonbuk, Republic of Korea; (J.-S.K.); (E.-B.L.); (J.-H.C.); (J.J.); (H.-H.J.); (S.-Y.P.)
| | - Hwan-Hee Jang
- Functional Food Division, Department of Agro-food Resources, National Institute of Agricultural Sciences, Rural Development Administration, Wanju 55365, Jeonbuk, Republic of Korea; (J.-S.K.); (E.-B.L.); (J.-H.C.); (J.J.); (H.-H.J.); (S.-Y.P.)
| | - Shin-Young Park
- Functional Food Division, Department of Agro-food Resources, National Institute of Agricultural Sciences, Rural Development Administration, Wanju 55365, Jeonbuk, Republic of Korea; (J.-S.K.); (E.-B.L.); (J.-H.C.); (J.J.); (H.-H.J.); (S.-Y.P.)
| | - Ki-Chan Ha
- Healthcare Claims & Management Incorporation, Jeonju 54858, Jeonbuk, Republic of Korea; (K.-C.H.); (Y.-K.P.)
| | - Yu-Kyung Park
- Healthcare Claims & Management Incorporation, Jeonju 54858, Jeonbuk, Republic of Korea; (K.-C.H.); (Y.-K.P.)
| | - Jong-Cheon Joo
- Department of Sasang Constitutional Medicine, College of Korean Medicine, Wonkwang University, Iksan 54596, Jeonbuk, Republic of Korea;
| | - Sung-Hyen Lee
- Functional Food Division, Department of Agro-food Resources, National Institute of Agricultural Sciences, Rural Development Administration, Wanju 55365, Jeonbuk, Republic of Korea; (J.-S.K.); (E.-B.L.); (J.-H.C.); (J.J.); (H.-H.J.); (S.-Y.P.)
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7
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Iker Etchegaray J, Kelley S, Penberthy K, Karvelyte L, Nagasaka Y, Gasperino S, Paul S, Seshadri V, Raymond M, Marco AR, Pinney J, Stremska M, Barron B, Lucas C, Wase N, Fan Y, Unanue E, Kundu B, Burstyn-Cohen T, Perry J, Ambati J, Ravichandran KS. Phagocytosis in the retina promotes local insulin production in the eye. Nat Metab 2023; 5:207-218. [PMID: 36732622 PMCID: PMC10457724 DOI: 10.1038/s42255-022-00728-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 12/16/2022] [Indexed: 02/04/2023]
Abstract
The retina is highly metabolically active, relying on glucose uptake and aerobic glycolysis. Situated in close contact to photoreceptors, a key function of cells in the retinal pigment epithelium (RPE) is phagocytosis of damaged photoreceptor outer segments (POS). Here we identify RPE as a local source of insulin in the eye that is stimulated by POS phagocytosis. We show that Ins2 messenger RNA and insulin protein are produced by RPE cells and that this production correlates with RPE phagocytosis of POS. Genetic deletion of phagocytic receptors ('loss of function') reduces Ins2, whereas increasing the levels of the phagocytic receptor MerTK ('gain of function') increases Ins2 production in male mice. Contrary to pancreas-derived systemic insulin, RPE-derived local insulin is stimulated during starvation, which also increases RPE phagocytosis. Global or RPE-specific Ins2 gene deletion decreases retinal glucose uptake in starved male mice, dysregulates retinal physiology, causes defects in phototransduction and exacerbates photoreceptor loss in a mouse model of retinitis pigmentosa. Collectively, these data identify RPE cells as a phagocytosis-induced local source of insulin in the retina, with the potential to influence retinal physiology and disease.
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Affiliation(s)
- J Iker Etchegaray
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Shannon Kelley
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Kristen Penberthy
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
| | - Laura Karvelyte
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Yosuke Nagasaka
- Center for Advanced Vision Science, University of Virginia, Charlottesville, VA, USA
| | - Sofia Gasperino
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Soumen Paul
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA, USA
| | - Vikram Seshadri
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA, USA
| | - Michael Raymond
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
| | - Ana Royo Marco
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
| | - Jonathan Pinney
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
| | - Marta Stremska
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Brady Barron
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Christopher Lucas
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
- University of Edinburgh, Edinburgh, UK
| | - Nishikant Wase
- Biomolecular Analysis Facility, University of Virginia, Charlottesville, VA, USA
| | - Yong Fan
- Drexel University, Philadelphia, PA, USA
| | - Emil Unanue
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Bijoy Kundu
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA, USA
| | - Tal Burstyn-Cohen
- Hadassah Medical School, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Justin Perry
- Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Jayakrishna Ambati
- Center for Advanced Vision Science, University of Virginia, Charlottesville, VA, USA
- Ophthalmology, University of Virginia, Charlottesville, VA, USA
| | - Kodi S Ravichandran
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA.
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA.
- Hadassah Medical School, Hebrew University of Jerusalem, Jerusalem, Israel.
- VIB/UGent Inflammation Research Centre, and Biomedical Molecular Biology, Ghent University, Ghent, Belgium.
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Sui X, Wang H, Wu F, Yang C, Zhang H, Xu Z, Guo Y, Guo Z, Xin B, Ma T, Li Y, Dai Z. Hepatic metabolite responses to 4-day complete fasting and subsequent refeeding in rats. PeerJ 2022; 10:e14009. [PMID: 36157064 PMCID: PMC9504452 DOI: 10.7717/peerj.14009] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 08/15/2022] [Indexed: 01/19/2023] Open
Abstract
Background Fasting has been widely used to improve various metabolic diseases in humans. Adaptive fasting is necessary for metabolic adaptation during prolonged fasting, which could overcome the great advantages of short-term fasting. The liver is the main organ responsible for energy metabolism and metabolic homeostasis. To date, we lack literature that describes the physiologically relevant adaptations of the liver during prolonged fasting and refeeding. For that reason, this study aims to evaluate the response of the liver of Sprague-Dawley (SD) rats to prolonged fasting and refeeding. Methods Sixty-six male SD rats were divided into the fasting groups, which were fasted for 0, 4, 8, 12, 24, 48, 72, or 96 h, and the refeeding groups, which were refed for 1, 3, or 6 days after 96 h of fasting. Serum glucose, TG, FFA, β-hydroxybutyrate, insulin, glucagon, leptin, adiponectin and FGF21 levels were assessed. The glucose content, PEPCK activity, TG concentration and FFA content were measured in liver tissue, and the expression of genes involved in gluconeogenesis (PEPCK and G6Pase), ketogenesis (PPARα, CPT-1a and HMGCS2) and the protein expression of nutrient-sensing signaling molecules (AMPK, mTOR and SIRT1) were determined by RT-qPCR and western blotting, respectively. Results Fasting significantly decreased the body weight, which was totally recovered to baseline after 3 days of refeeding. A 4-day fast triggered an energy metabolic substrate shift from glucose to ketones and caused serum hormone changes and changes in the protein expression levels of nutrient-sensing signaling molecules. Glycogenolysis served as the primary fuel source during the first 24 h of fasting, while gluconeogenesis supplied the most glucose thereafter. Serum FFA concentrations increased significantly with 48 h of fasting. Serum FFAs partly caused high serum β-hydroxybutyrate levels, which became an important energy source with the prolongation of the fasting duration. One day of refeeding quickly reversed the energy substrate switch. Nutrient-sensing signaling molecules (AMPK and SIRT1 but not mTOR signaling) were highly expressed at the beginning of fasting (in the first 4 h). Serum insulin and leptin decreased with fasting initiation, and serum glucagon increased, but adiponectin and FGF21 showed no significant changes. Herein, we depicted in detail the timing of the metabolic response and adaptation of the liver to a 4-day water-only fast and subsequent refeeding in rats, which provides helpful support for the design of safe prolonged and intermittent fasting regimens.
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Affiliation(s)
- Xiukun Sui
- Department of Electronic and Information Engineering, Harbin Institute of Technology at Shenzhen, Shenzhen, China,State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China,Space Science and Technology Institute, Shenzhen, China
| | - Hailong Wang
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Feng Wu
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Chao Yang
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Hongyu Zhang
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Zihan Xu
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Yaxiu Guo
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - ZhiFeng Guo
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Bingmu Xin
- Space Science and Technology Institute, Shenzhen, China
| | - Ting Ma
- Department of Electronic and Information Engineering, Harbin Institute of Technology at Shenzhen, Shenzhen, China
| | - Yinghui Li
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Zhongquan Dai
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
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9
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Prolonged insulin-induced hypoglycaemia reduces ß-cell activity rather than number in pancreatic islets in non-diabetic rats. Sci Rep 2022; 12:14113. [PMID: 35982111 PMCID: PMC9388517 DOI: 10.1038/s41598-022-18398-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 08/10/2022] [Indexed: 12/05/2022] Open
Abstract
Pancreatic β-cells have an extraordinary ability to adapt to acute fluctuations in glucose levels by rapid changing insulin production to meet metabolic needs. Although acute changes have been characterised, effects of prolonged metabolic stress on β-cell dynamics are still unclear. Here, the aim was to investigate pancreatic β-cell dynamics and function during and after prolonged hypoglycaemia. Hypoglycaemia was induced in male and female rats by infusion of human insulin for 8 weeks, followed by a 4-week infusion-free recovery period. Animals were euthanized after 4 or 8 weeks of infusion, and either 2 days and 4 weeks after infusion-stop. Total volumes of pancreatic islets and β-cell nuclei, islet insulin and glucagon content, and plasma c-peptide levels were quantified. Prolonged hypoglycaemia reduced c-peptide levels, islet volume and almost depleted islet insulin. Relative β-cell nuclei: total pancreas volume decreased, while being unchanged relative to islet volume. Glucagon: total pancreas volume decreased during hypoglycaemia, whereas glucagon: islet volume increased. Within two days after infusion-stop, plasma glucose and c-peptide levels normalised and all remaining parameters were fully reversed after 4 weeks. In conclusion, our findings indicate that prolonged hypoglycaemia inactivates β-cells, which can rapidly be reactivated when needed, demonstrating the high plasticity of β-cells even following prolonged suppression.
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10
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Morriseau TS, Doucette CA, Dolinsky VW. More than meets the islet: aligning nutrient and paracrine inputs with hormone secretion in health and disease. Am J Physiol Endocrinol Metab 2022; 322:E446-E463. [PMID: 35373587 DOI: 10.1152/ajpendo.00411.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The pancreatic islet is responsive to an array of endocrine, paracrine, and nutritional inputs that adjust hormone secretion to ensure accurate control of glucose homeostasis. Although the mechanisms governing glucose-coupled insulin secretion have received the most attention, there is emerging evidence for a multitude of physiological signaling pathways and paracrine networks that collectively regulate insulin, glucagon, and somatostatin release. Moreover, the modulation of these pathways in conditions of glucotoxicity or lipotoxicity are areas of both growing interest and controversy. In this review, the contributions of external, intrinsic, and paracrine factors in pancreatic β-, α-, and δ-cell secretion across the full spectrum of physiological (i.e., fasting and fed) and pathophysiological (gluco- and lipotoxicity; diabetes) environments will be critically discussed.
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Affiliation(s)
- Taylor S Morriseau
- Diabetes Research Envisioned and Accomplished in Manitoba (DREAM) Theme of the Children's Hospital Research Institute of Manitoba, Winnipeg, Manitoba, Canada
- Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Christine A Doucette
- Diabetes Research Envisioned and Accomplished in Manitoba (DREAM) Theme of the Children's Hospital Research Institute of Manitoba, Winnipeg, Manitoba, Canada
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Vernon W Dolinsky
- Diabetes Research Envisioned and Accomplished in Manitoba (DREAM) Theme of the Children's Hospital Research Institute of Manitoba, Winnipeg, Manitoba, Canada
- Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, Manitoba, Canada
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11
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Bian C, Zhang H, Gao J, Wang Y, Li J, Guo D, Wang W, Song Y, Weng Y, Ren H. SIRT6 regulates SREBP1c-induced glucolipid metabolism in liver and pancreas via the AMPKα-mTORC1 pathway. J Transl Med 2022; 102:474-484. [PMID: 34923569 DOI: 10.1038/s41374-021-00715-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 11/11/2021] [Accepted: 11/12/2021] [Indexed: 11/09/2022] Open
Abstract
The aim of this study was to determine the mechanism by which SIRT6 regulates glucolipid metabolism disorders. We detected histological and molecular changes in Sprague-Dawley rats as well as in BRL 3A and INS-1 cell lines subjected to overnutrition and starvation. SIRT6, SREBP1c, and glucolipid metabolism biomarkers were identified by fluorescence co-localization, real-time PCR, and western blotting. Gene silencing studies were performed. Recombinant SIRT6, AMPK agonist (AICAR), mTOR inhibitor (rapamycin), and liver X receptor (LXR) agonist (T0901317) were used to pre-treated in BRL 3A and INS-1 cells. Real-time PCR and western blotting were used to detect related proteins, and cell counting was utilized to detect proliferation. We obtained conflicting results; SIRT6 and SREBP1c appeared in both the liver and pancreas of high-fat and hungry rats. Recombinant SIRT6 alleviated the decrease in AMPKα and increase in mTORC1 (complex of mTOR, Raptor, and Rheb) caused by overnutrition. SIRT6 siRNA reversed the glucolipid metabolic disorders caused by the AMPK agonist and mTOR inhibitor but not by the LXR agonist. Taken together, our results demonstrate that SIRT6 regulates glycolipid metabolism through AMPKα-mTORC1 regulating SREBP1c in the liver and pancreas induced by overnutrition and starvation, independent of LXR.
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Affiliation(s)
- Che Bian
- Department of Endocrinology and Metabolism, The Fourth Affiliated Hospital of China Medical University, Shenyang, China
| | - Haibo Zhang
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, Liaoning, China
| | - Jing Gao
- Department of Gerontology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Yuxia Wang
- Department of Endocrinology and Metabolism, The Fourth Affiliated Hospital of China Medical University, Shenyang, China
| | - Jia Li
- Department of Endocrinology and Metabolism, The Fourth Affiliated Hospital of China Medical University, Shenyang, China
| | - Dan Guo
- Department of Endocrinology and Metabolism, The Fourth Affiliated Hospital of China Medical University, Shenyang, China
| | - Wei Wang
- Department of Endocrinology and Metabolism, The Fourth Affiliated Hospital of China Medical University, Shenyang, China
| | - Yuling Song
- Department of Endocrinology and Metabolism, The Fourth Affiliated Hospital of China Medical University, Shenyang, China
| | - Yang Weng
- Department of Gastroenterology, The Fourth Affiliated Hospital of China Medical University, Shenyang, China
| | - Huiwen Ren
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, Liaoning, China.
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12
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Rohli KE, Boyer CK, Blom SE, Stephens SB. Nutrient Regulation of Pancreatic Islet β-Cell Secretory Capacity and Insulin Production. Biomolecules 2022; 12:335. [PMID: 35204835 PMCID: PMC8869698 DOI: 10.3390/biom12020335] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/16/2022] [Accepted: 02/17/2022] [Indexed: 01/27/2023] Open
Abstract
Pancreatic islet β-cells exhibit tremendous plasticity for secretory adaptations that coordinate insulin production and release with nutritional demands. This essential feature of the β-cell can allow for compensatory changes that increase secretory output to overcome insulin resistance early in Type 2 diabetes (T2D). Nutrient-stimulated increases in proinsulin biosynthesis may initiate this β-cell adaptive compensation; however, the molecular regulators of secretory expansion that accommodate the increased biosynthetic burden of packaging and producing additional insulin granules, such as enhanced ER and Golgi functions, remain poorly defined. As these adaptive mechanisms fail and T2D progresses, the β-cell succumbs to metabolic defects resulting in alterations to glucose metabolism and a decline in nutrient-regulated secretory functions, including impaired proinsulin processing and a deficit in mature insulin-containing secretory granules. In this review, we will discuss how the adaptative plasticity of the pancreatic islet β-cell's secretory program allows insulin production to be carefully matched with nutrient availability and peripheral cues for insulin signaling. Furthermore, we will highlight potential defects in the secretory pathway that limit or delay insulin granule biosynthesis, which may contribute to the decline in β-cell function during the pathogenesis of T2D.
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Affiliation(s)
- Kristen E. Rohli
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA; (K.E.R.); (C.K.B.); (S.E.B.)
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Cierra K. Boyer
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA; (K.E.R.); (C.K.B.); (S.E.B.)
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA 52242, USA
| | - Sandra E. Blom
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA; (K.E.R.); (C.K.B.); (S.E.B.)
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Samuel B. Stephens
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA; (K.E.R.); (C.K.B.); (S.E.B.)
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA
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13
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Boland BB, Laker RC, O'Brien S, Sitaula S, Sermadiras I, Nielsen JC, Barkholt P, Roostalu U, Hecksher-Sørensen J, Sejthen SR, Thorbek DD, Suckow A, Burmeister N, Oldham S, Will S, Howard VG, Gill BM, Newton P, Naylor J, Hornigold DC, Austin J, Lantier L, McGuinness OP, Trevaskis JL, Grimsby JS, Rhodes CJ. Peptide-YY 3-36/glucagon-like peptide-1 combination treatment of obese diabetic mice improves insulin sensitivity associated with recovered pancreatic β-cell function and synergistic activation of discrete hypothalamic and brainstem neuronal circuitries. Mol Metab 2021; 55:101392. [PMID: 34781035 PMCID: PMC8717237 DOI: 10.1016/j.molmet.2021.101392] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 10/22/2021] [Accepted: 11/04/2021] [Indexed: 01/27/2023] Open
Abstract
OBJECTIVE Obesity-linked type 2 diabetes (T2D) is a worldwide health concern and many novel approaches are being considered for its treatment and subsequent prevention of serious comorbidities. Co-administration of glucagon like peptide 1 (Fc-GLP-1) and peptide YY3-36 (Fc-PYY3-36) renders a synergistic decrease in energy intake in obese men. However, mechanistic details of the synergy between these peptide agonists and their effects on metabolic homeostasis remain relatively scarce. METHODS In this study, we utilized long-acting analogues of GLP-1 and PYY3-36 (via Fc-peptide conjugation) to better characterize the synergistic pharmacological benefits of their co-administration on body weight and glycaemic regulation in obese and diabetic mouse models. Hyperinsulinemic-euglycemic clamps were used to measure weight-independent effects of Fc-PYY3-36 + Fc-GLP-1 on insulin action. Fluorescent light sheet microscopy analysis of whole brain was performed to assess activation of brain regions. RESULTS Co-administration of long-acting Fc-IgG/peptide conjugates of Fc-GLP-1 and Fc-PYY3-36 (specific for PYY receptor-2 (Y2R)) resulted in profound weight loss, restored glucose homeostasis, and recovered endogenous β-cell function in two mouse models of obese T2D. Hyperinsulinemic-euglycemic clamps in C57BLKS/J db/db and diet-induced obese Y2R-deficient (Y2RKO) mice indicated Y2R is required for a weight-independent improvement in peripheral insulin sensitivity and enhanced hepatic glycogenesis. Brain cFos staining demonstrated distinct temporal activation of regions of the hypothalamus and hindbrain following Fc-PYY3-36 + Fc-GLP-1R agonist administration. CONCLUSIONS These results reveal a therapeutic approach for obesity/T2D that improved insulin sensitivity and restored endogenous β-cell function. These data also highlight the potential association between the gut-brain axis in control of metabolic homeostasis.
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Affiliation(s)
- Brandon B Boland
- Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA; Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK; Gubra ApS, Horsholm, Denmark; PRECISIONscientia, Yardley, PA, USA
| | - Rhianna C Laker
- Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA; Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | - Siobhan O'Brien
- Antibody and Protein Engineering, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA; Antibody and Protein Engineering, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | - Sadichha Sitaula
- Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA; Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | - Isabelle Sermadiras
- Antibody and Protein Engineering, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA; Antibody and Protein Engineering, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | | | | | | | | | | | | | - Arthur Suckow
- Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA; Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK; DTX Pharma, San Diego, CA, USA
| | - Nicole Burmeister
- Antibody and Protein Engineering, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA; Antibody and Protein Engineering, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK; Roche, Penzberg, Germany
| | - Stephanie Oldham
- Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA; Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | - Sarah Will
- Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA; Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | - Victor G Howard
- Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA; Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | - Benji M Gill
- Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA; Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | - Philip Newton
- Antibody and Protein Engineering, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA; Antibody and Protein Engineering, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | - Jacqueline Naylor
- Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA; Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | - David C Hornigold
- Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA; Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | - Jotham Austin
- University of Chicago Advanced Electron Microscopy Core Facility, Chicago, IL, USA
| | - Louise Lantier
- Vanderbilt University Mouse Metabolic Phenotyping Center, Nashville, TN, USA
| | - Owen P McGuinness
- Vanderbilt University Mouse Metabolic Phenotyping Center, Nashville, TN, USA
| | - James L Trevaskis
- Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA; Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK; Gilead Sciences, Foster City, CA, USA
| | - Joseph S Grimsby
- Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA; Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | - Christopher J Rhodes
- Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA; Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK.
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14
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Metabolic Phenotypes and Step by Step Evolution of Type 2 Diabetes: A New Paradigm. Biomedicines 2021; 9:biomedicines9070800. [PMID: 34356863 PMCID: PMC8301386 DOI: 10.3390/biomedicines9070800] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 07/02/2021] [Accepted: 07/05/2021] [Indexed: 01/18/2023] Open
Abstract
Unlike bolus insulin secretion mechanisms, basal insulin secretion is poorly understood. It is essential to elucidate these mechanisms in non-hyperinsulinaemia healthy persons. This establishes a baseline for investigation into pathologies where these processes are dysregulated, such as in type 2 diabetes (T2DM), cardiovascular disease (CVD), certain cancers and dementias. Chronic hyperinsulinaemia enforces glucose fueling, depleting the NAD+ dependent antioxidant activity that increases mitochondrial reactive oxygen species (mtROS). Consequently, beta-cell mitochondria increase uncoupling protein expression, which decreases the mitochondrial ATP surge generation capacity, impairing bolus mediated insulin exocytosis. Excessive ROS increases the Drp1:Mfn2 ratio, increasing mitochondrial fission, which increases mtROS; endoplasmic reticulum-stress and impaired calcium homeostasis ensues. Healthy individuals in habitual ketosis have significantly lower glucagon and insulin levels than T2DM individuals. As beta-hydroxybutyrate rises, hepatic gluconeogenesis and glycogenolysis supply extra-hepatic glucose needs, and osteocalcin synthesis/release increases. We propose insulin’s primary role is regulating beta-hydroxybutyrate synthesis, while the role of bone regulates glucose uptake sensitivity via osteocalcin. Osteocalcin regulates the alpha-cell glucagon secretory profile via glucagon-like peptide-1 and serotonin, and beta-hydroxybutyrate synthesis via regulating basal insulin levels. Establishing metabolic phenotypes aids in resolving basal insulin secretion regulation, enabling elucidation of the pathological changes that occur and progress into chronic diseases associated with ageing.
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15
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Corezola do Amaral ME, Kravets V, Dwulet JM, Farnsworth NL, Piscopio R, Schleicher WE, Miranda JG, Benninger RKP. Caloric restriction recovers impaired β-cell-β-cell gap junction coupling, calcium oscillation coordination, and insulin secretion in prediabetic mice. Am J Physiol Endocrinol Metab 2020; 319:E709-E720. [PMID: 32830549 PMCID: PMC7750515 DOI: 10.1152/ajpendo.00132.2020] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 08/14/2020] [Accepted: 08/14/2020] [Indexed: 12/16/2022]
Abstract
Caloric restriction can decrease the incidence of metabolic diseases, such as obesity and Type 2 diabetes mellitus. The mechanisms underlying the benefits of caloric restriction involved in insulin secretion and glucose homeostasis are not fully understood. Intercellular communication within the islets of Langerhans, mediated by Connexin36 (Cx36) gap junctions, regulates insulin secretion dynamics and glucose homeostasis. The goal of this study was to determine whether caloric restriction can protect against decreases in Cx36 gap junction coupling and altered islet function induced in models of obesity and prediabetes. C57BL6 mice were fed with a high-fat diet (HFD), showing indications of prediabetes after 2 mo, including weight gain, insulin resistance, and elevated fasting glucose and insulin levels. Subsequently, mice were submitted to 1 mo of 40% caloric restriction (2 g/day of HFD). Mice under 40% caloric restriction showed reversal in weight gain and recovered insulin sensitivity, fasting glucose, and insulin levels. In islets of mice fed the HFD, caloric restriction protected against obesity-induced decreases in gap junction coupling and preserved glucose-stimulated calcium signaling, including Ca2+ oscillation coordination and oscillation amplitude. Caloric restriction also promoted a slight increase in glucose metabolism, as measured by increased NAD(P)H autofluorescence, as well as recovering glucose-stimulated insulin secretion. We conclude that declines in Cx36 gap junction coupling that occur in obesity can be completely recovered by caloric restriction and obesity reversal, improving Ca2+ dynamics and insulin secretion regulation. This suggests a critical role for caloric restriction in the context of obesity to prevent islet dysfunction.
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Affiliation(s)
| | - Vira Kravets
- Barbara Davis Center for Childhood Diabetes, University of Colorado Anschutz Medical Campus, Aurora, Denver, Colorado
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, Denver, Colorado
| | - JaeAnn M. Dwulet
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, Denver, Colorado
| | - Nikki L. Farnsworth
- Barbara Davis Center for Childhood Diabetes, University of Colorado Anschutz Medical Campus, Aurora, Denver, Colorado
| | - Robert Piscopio
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, Denver, Colorado
| | - Wolfgang E. Schleicher
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, Denver, Colorado
| | - Jose Guadalupe Miranda
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, Denver, Colorado
| | - Richard K. P. Benninger
- Barbara Davis Center for Childhood Diabetes, University of Colorado Anschutz Medical Campus, Aurora, Denver, Colorado
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, Denver, Colorado
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16
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Yau B, Hays L, Liang C, Laybutt DR, Thomas HE, Gunton JE, Williams L, Hawthorne WJ, Thorn P, Rhodes CJ, Kebede MA. A fluorescent timer reporter enables sorting of insulin secretory granules by age. J Biol Chem 2020; 295:8901-8911. [PMID: 32341128 PMCID: PMC7335792 DOI: 10.1074/jbc.ra120.012432] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 03/21/2020] [Indexed: 01/03/2023] Open
Abstract
Within the pancreatic β-cells, insulin secretory granules (SGs) exist in functionally distinct pools, displaying variations in motility as well as docking and fusion capability. Current therapies that increase insulin secretion do not consider the existence of these distinct SG pools. Accordingly, these approaches are effective only for a short period, with a worsening of glycemia associated with continued decline in β-cell function. Insulin granule age is underappreciated as a determinant for why an insulin granule is selected for secretion and may explain why newly synthesized insulin is preferentially secreted from β-cells. Here, using a novel fluorescent timer protein, we aimed to investigate the preferential secretion model of insulin secretion and identify how granule aging is affected by variation in the β-cell environment, such as hyperglycemia. We demonstrate the use of a fluorescent timer construct, syncollin-dsRedE5TIMER, which changes its fluorescence from green to red over 18 h, in both microscopy and fluorescence-assisted organelle-sorting techniques. We confirm that the SG-targeting construct localizes to insulin granules in β-cells and does not interfere with normal insulin SG behavior. We visualize insulin SG aging behavior in MIN6 and INS1 β-cell lines and in primary C57BL/6J mouse and nondiabetic human islet cells. Finally, we separated young and old insulin SGs, revealing that preferential secretion of younger granules occurs in glucose-stimulated insulin secretion. We also show that SG population age is modulated by the β-cell environment in vivo in the db/db mouse islets and ex vivo in C57BL/6J islets exposed to different glucose environments.
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Affiliation(s)
- Belinda Yau
- Charles Perkins Centre, University of Sydney, Sydney, New South Wales, Australia; School of Life and Environmental Sciences, Faculty of Science, University of Sydney, Sydney, New South Wales, Australia
| | - Lori Hays
- STEM-Department of Biology, Edmonds Community College, Lynnwood, Washington, USA
| | - Cassandra Liang
- Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - D Ross Laybutt
- Garvan Institute of Medical Research, Sydney, New South Wales, Australia; St. Vincent's Clinical School, University of New South Wales Sydney, Sydney, New South Wales, Australia
| | - Helen E Thomas
- St. Vincent's Institute, Fitzroy, Victoria, Australia; Department of Medicine, St. Vincent's Hospital, University of Melbourne, Fitzroy, Victoria, Australia
| | - Jenny E Gunton
- Faculty of Medicine and Health, the University of Sydney, Sydney, New South Wales, Australia; The Westmead Institute for Medical Research, University of Sydney, Westmead, New South Wales, Australia
| | - Lindy Williams
- Faculty of Medicine and Health, the University of Sydney, Sydney, New South Wales, Australia; National Pancreas and Islet Transplant Unit (NPITU), Westmead Hospital, Sydney, New South Wales, Australia
| | - Wayne J Hawthorne
- Faculty of Medicine and Health, the University of Sydney, Sydney, New South Wales, Australia; National Pancreas and Islet Transplant Unit (NPITU), Westmead Hospital, Sydney, New South Wales, Australia
| | - Peter Thorn
- Charles Perkins Centre, University of Sydney, Sydney, New South Wales, Australia; Discipline of Physiology, School of Medical Sciences, Faculty of Medicine and Health, Charles Perkins Centre, University of Sydney, Camperdown, New South Wales, Australia
| | - Christopher J Rhodes
- Research and Early Development, Cardiovascular, Renal and Metabolic Diseases, BioPharmaceuticals R&D, AstraZeneca Ltd, Gaithersburg, Maryland, USA; Pacific Northwest Research Institute, Seattle, Washington, USA
| | - Melkam A Kebede
- Charles Perkins Centre, University of Sydney, Sydney, New South Wales, Australia; School of Life and Environmental Sciences, Faculty of Science, University of Sydney, Sydney, New South Wales, Australia.
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17
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Association between famine exposure in early life with insulin resistance and beta cell dysfunction in adulthood. Nutr Diabetes 2020; 10:18. [PMID: 32514025 PMCID: PMC7280514 DOI: 10.1038/s41387-020-0121-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 05/21/2020] [Accepted: 05/22/2020] [Indexed: 02/07/2023] Open
Abstract
Objectives Famine exposure in early life was associated with type 2 diabetes, non-alcoholic fatty liver disease and metabolic syndrome, etc. But evidence in early famine exposure and insulin resistance and beta cell dysfunction were limited. We aimed to investigate whether the association existed between famine exposure in early life and beta cell dysfunction and insulin resistance in adulthood. Methods In all, 7912 non-diabetic participants were included in this study, based on SPECT-China study. Participants with fetal or childhood famine exposure (birth year 1949–1962) were exposure group. Insulin resistance was estimated by the homeostasis model assessment index of insulin resistance (HOMA-IR). Beta cell function, represented by insulin secretion, was estimated by the disposition index. The associations of famine exposure with HOMA-IR and disposition index were assessed via linear regression. Results In men, we did not observe a significant association between early life famine exposure and ln(HOMA-IR) in all three models (P > 0.05 for all). However, in women, early life famine exposure were found to have significant association with ln(HOMA-IR) after adjustments for urbanization, severity of famine exposure, current smoker, waist circumference, hypertension, and dyslipidemia (unstandardized coefficients 0.055, 95% confidence interval 0.021, 0.088, P = 0.001). Early life famine exposure was observed to be negatively associated with ln(disposition index) after adjustments for the above potential confounders, both in men (model 3: unstandardized coefficients −0.042, 95% confidence interval −0.072,−0.012, P = 0.006) and women (model 3: unstandardized coefficients −0.033, 95% confidence interval −0.058,−0.009, P = 0.008). Conclusions In conclusion, exposure to famine in fetal- and childhood- life period is associated with beta cell dysfunction in males and females without diabetes, but early life famine exposure was only associated with insulin resistance in non-diabetic females. These results indicate that malnutrition in early life period may offer a modifiable factor for type 2 diabetes development.
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18
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Kang T, Boland BB, Jensen P, Alarcon C, Nawrocki A, Grimsby JS, Rhodes CJ, Larsen MR. Characterization of Signaling Pathways Associated with Pancreatic β-cell Adaptive Flexibility in Compensation of Obesity-linked Diabetes in db/db Mice. Mol Cell Proteomics 2020; 19:971-993. [PMID: 32265294 PMCID: PMC7261816 DOI: 10.1074/mcp.ra119.001882] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 03/03/2020] [Indexed: 12/20/2022] Open
Abstract
The onset of obesity-linked type 2 diabetes (T2D) is marked by an eventual failure in pancreatic β-cell function and mass that is no longer able to compensate for the inherent insulin resistance and increased metabolic load intrinsic to obesity. However, in a commonly used model of T2D, the db/db mouse, β-cells have an inbuilt adaptive flexibility enabling them to effectively adjust insulin production rates relative to the metabolic demand. Pancreatic β-cells from these animals have markedly reduced intracellular insulin stores, yet high rates of (pro)insulin secretion, together with a substantial increase in proinsulin biosynthesis highlighted by expanded rough endoplasmic reticulum and Golgi apparatus. However, when the metabolic overload and/or hyperglycemia is normalized, β-cells from db/db mice quickly restore their insulin stores and normalize secretory function. This demonstrates the β-cell's adaptive flexibility and indicates that therapeutic approaches applied to encourage β-cell rest are capable of restoring endogenous β-cell function. However, mechanisms that regulate β-cell adaptive flexibility are essentially unknown. To gain deeper mechanistic insight into the molecular events underlying β-cell adaptive flexibility in db/db β-cells, we conducted a combined proteomic and post-translational modification specific proteomic (PTMomics) approach on islets from db/db mice and wild-type controls (WT) with or without prior exposure to normal glucose levels. We identified differential modifications of proteins involved in redox homeostasis, protein refolding, K48-linked deubiquitination, mRNA/protein export, focal adhesion, ERK1/2 signaling, and renin-angiotensin-aldosterone signaling, as well as sialyltransferase activity, associated with β-cell adaptive flexibility. These proteins are all related to proinsulin biosynthesis and processing, maturation of insulin secretory granules, and vesicular trafficking-core pathways involved in the adaptation of insulin production to meet metabolic demand. Collectively, this study outlines a novel and comprehensive global PTMome signaling map that highlights important molecular mechanisms related to the adaptive flexibility of β-cell function, providing improved insight into disease pathogenesis of T2D.
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Affiliation(s)
- Taewook Kang
- Protein research group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark; The Danish Diabetes Academy, Odense, Denmark
| | - Brandon B Boland
- The Kovler Diabetes Center, Department of Medicine Section of Endocrinology, Diabetes & Metabolism, University of Chicago, Chicago, Illinois 60637; Cardiovascular, Renal and Metabolic Disease, BioPharmaceuticals Research and Development, AstraZeneca Gaithersburg, Maryland 20878
| | - Pia Jensen
- Protein research group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Cristina Alarcon
- The Kovler Diabetes Center, Department of Medicine Section of Endocrinology, Diabetes & Metabolism, University of Chicago, Chicago, Illinois 60637
| | - Arkadiusz Nawrocki
- Protein research group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Joseph S Grimsby
- Cardiovascular, Renal and Metabolic Disease, BioPharmaceuticals Research and Development, AstraZeneca Gaithersburg, Maryland 20878
| | - Christopher J Rhodes
- The Kovler Diabetes Center, Department of Medicine Section of Endocrinology, Diabetes & Metabolism, University of Chicago, Chicago, Illinois 60637; Cardiovascular, Renal and Metabolic Disease, BioPharmaceuticals Research and Development, AstraZeneca Gaithersburg, Maryland 20878
| | - Martin R Larsen
- Protein research group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark.
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19
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Bru-Tari E, Oropeza D, Herrera PL. Cell Heterogeneity and Paracrine Interactions in Human Islet Function: A Perspective Focused in β-Cell Regeneration Strategies. Front Endocrinol (Lausanne) 2020; 11:619150. [PMID: 33613453 PMCID: PMC7888438 DOI: 10.3389/fendo.2020.619150] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 12/14/2020] [Indexed: 12/27/2022] Open
Abstract
The β-cell regeneration field has shown a strong knowledge boost in the last 10 years. Pluripotent stem cell differentiation and direct reprogramming from other adult cell types are becoming more tangible long-term diabetes therapies. Newly generated β-like-cells consistently show hallmarks of native β-cells and can restore normoglycemia in diabetic mice in virtually all recent studies. Nonetheless, these cells still show important compromises in insulin secretion, cell metabolism, electrical activity, and overall survival, perhaps due to a lack of signal integration from other islet cells. Mounting data suggest that diabetes is not only a β-cell disease, as the other islet cell types also contribute to its physiopathology. Here, we present an update on the most recent studies of islet cell heterogeneity and paracrine interactions in the context of restoring an integrated islet function to improve β-cell replacement therapies.
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20
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Kang T, Boland BB, Alarcon C, Grimsby JS, Rhodes CJ, Larsen MR. Proteomic Analysis of Restored Insulin Production and Trafficking in Obese Diabetic Mouse Pancreatic Islets Following Euglycemia. J Proteome Res 2019; 18:3245-3258. [PMID: 31317746 DOI: 10.1021/acs.jproteome.9b00160] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
For the treatment of patients with prediabetes or diabetes, clinical evidence has emerged that β-cell function can be restored by glucose-lowering therapeutic strategies. However, little is known about the molecular mechanisms underlying this functional adaptive behavior of the pancreatic β-cell. This study examines the dynamic changes in protein expression and phosphorylation state associated with (pro)insulin production and secretory pathway function mediated by euglycemia to induce β-cell rest in obese/diabetic db/db islet β-cells. Unbiased quantitative profiling of the protein expression and phosphorylation events that occur upon β-cell adaption during the transition from hyperglycemia to euglycemia was assessed in isolated pancreatic islets from obese diabetic db/db and wild-type (WT) mice using quantitative proteomics and phosphoproteomics together with bioinformatics analysis. Dynamic changes in the expression and phosphorylation of proteins associated with pancreatic β-cell (pro)insulin production and complementary regulated-secretory pathway regulation were observed in obese diabetic db/db islets in a hyperglycemic environment, relative to WT mouse islets in a normal euglycemic environment, that resolved when isolated db/db islets were exposed to euglycemia for 12 h in vitro. By similarly treating WT islets in parallel, the effects of tissue culture could be mostly eliminated and only those changes associated with resolution by euglycemia were assessed. Among such regulated protein phosphorylation-dependent signaling events were those associated with COPII-coated vesicle-dependent ER exit, ER-to-Golgi trafficking, clathrin-coat disassembly, and a particular association for the luminal Golgi protein kinase, FAM20C, in control of distal secretory pathway trafficking, sorting, and granule biogenesis. Protein expression and especially phosphorylation play key roles in the regulation of (pro)insulin production, correlative secretory pathway trafficking, and the restoration of β-cell secretory capacity in the adaptive functional β-cell response to metabolic demand, especially that mediated by glucose.
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Affiliation(s)
- Taewook Kang
- Protein Research Group, Department of Biochemistry and Molecular Biology , University of Southern Denmark , DK-5230 Odense M , Denmark.,The Danish Diabetes Academy , 5000 Odense , Denmark
| | - Brandon B Boland
- The Kovler Diabetes Center, Department of Medicine Section of Endocrinology, Diabetes & Metabolism , University of Chicago , Chicago , Illinois 60637 , United States.,Cardiovascular, Renal and Metabolic Disease Research , MedImmune LLC , Gaithersburg , Maryland 20878 , United States
| | - Cristina Alarcon
- The Kovler Diabetes Center, Department of Medicine Section of Endocrinology, Diabetes & Metabolism , University of Chicago , Chicago , Illinois 60637 , United States
| | - Joseph S Grimsby
- Cardiovascular, Renal and Metabolic Disease Research , MedImmune LLC , Gaithersburg , Maryland 20878 , United States
| | - Christopher J Rhodes
- The Kovler Diabetes Center, Department of Medicine Section of Endocrinology, Diabetes & Metabolism , University of Chicago , Chicago , Illinois 60637 , United States.,Cardiovascular, Renal and Metabolic Disease Research , MedImmune LLC , Gaithersburg , Maryland 20878 , United States
| | - Martin R Larsen
- Protein Research Group, Department of Biochemistry and Molecular Biology , University of Southern Denmark , DK-5230 Odense M , Denmark
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21
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Boland BB, Brown C, Boland ML, Cann J, Sulikowski M, Hansen G, Grønlund RV, King W, Rondinone C, Trevaskis J, Rhodes CJ, Grimsby JS. Pancreatic β-Cell Rest Replenishes Insulin Secretory Capacity and Attenuates Diabetes in an Extreme Model of Obese Type 2 Diabetes. Diabetes 2019; 68:131-140. [PMID: 30305366 DOI: 10.2337/db18-0304] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 09/27/2018] [Indexed: 11/13/2022]
Abstract
The onset of common obesity-linked type 2 diabetes (T2D) is marked by exhaustive failure of pancreatic β-cell functional mass to compensate for insulin resistance and increased metabolic demand, leading to uncontrolled hyperglycemia. Here, the β-cell-deficient obese hyperglycemic/hyperinsulinemic KS db/db mouse model was used to assess consequential effects on β-cell functional recovery by lowering glucose homeostasis and/or improving insulin sensitivity after treatment with thiazolidinedione therapy or glucagon-like peptide 1 receptor agonism alone or in combination with sodium/glucose cotransporter 2 inhibition (SGLT-2i). SGLT-2i combination therapies improved glucose homeostasis, independent of changes in body weight, resulting in a synergistic increase in pancreatic insulin content marked by significant recovery of the β-cell mature insulin secretory population but with limited changes in β-cell mass and no indication of β-cell dedifferentiation. Restoration of β-cell insulin secretory capacity also restored biphasic insulin secretion. These data emphasize that by therapeutically alleviating the demand for insulin in vivo, irrespective of weight loss, endogenous β-cells recover significant function that can contribute to attenuating diabetes. Thus, this study provides evidence that alleviation of metabolic demand on the β-cell, rather than targeting the β-cell itself, could be effective in delaying the progression of T2D.
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Affiliation(s)
- Brandon B Boland
- Division of Cardiovascular and Metabolic Disease, MedImmune LLC, Gaithersburg, MD
- Gubra ApS, Hørsholm, Denmark
| | - Charles Brown
- Division of Cardiovascular and Metabolic Disease, MedImmune LLC, Gaithersburg, MD
| | - Michelle L Boland
- Division of Cardiovascular and Metabolic Disease, MedImmune LLC, Gaithersburg, MD
- Gubra ApS, Hørsholm, Denmark
| | - Jennifer Cann
- Division of Cardiovascular and Metabolic Disease, MedImmune LLC, Gaithersburg, MD
| | - Michal Sulikowski
- Division of Cardiovascular and Metabolic Disease, MedImmune LLC, Gaithersburg, MD
| | | | | | - Wanda King
- Division of Cardiovascular and Metabolic Disease, MedImmune LLC, Gaithersburg, MD
| | - Cristina Rondinone
- Division of Cardiovascular and Metabolic Disease, MedImmune LLC, Gaithersburg, MD
| | - James Trevaskis
- Division of Cardiovascular and Metabolic Disease, MedImmune LLC, Gaithersburg, MD
| | - Christopher J Rhodes
- Division of Cardiovascular and Metabolic Disease, MedImmune LLC, Gaithersburg, MD
| | - Joseph S Grimsby
- Division of Cardiovascular and Metabolic Disease, MedImmune LLC, Gaithersburg, MD
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22
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Boland ML, Oldham S, Boland BB, Will S, Lapointe JM, Guionaud S, Rhodes CJ, Trevaskis JL. Nonalcoholic steatohepatitis severity is defined by a failure in compensatory antioxidant capacity in the setting of mitochondrial dysfunction. World J Gastroenterol 2018; 24:1748-1765. [PMID: 29713129 PMCID: PMC5922994 DOI: 10.3748/wjg.v24.i16.1748] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 02/22/2018] [Accepted: 02/25/2018] [Indexed: 02/06/2023] Open
Abstract
AIM To comprehensively evaluate mitochondrial (dys) function in preclinical models of nonalcoholic steatohepatitis (NASH).
METHODS We utilized two readily available mouse models of nonalcoholic fatty liver disease (NAFLD) with or without progressive fibrosis: Lepob/Lepob (ob/ob) and FATZO mice on high trans-fat, high fructose and high cholesterol (AMLN) diet. Presence of NASH was assessed using immunohistochemical and pathological techniques, and gene expression profiling. Morphological features of mitochondria were assessed via transmission electron microscopy and immunofluorescence, and function was assessed by measuring oxidative capacity in primary hepatocytes, and respiratory control and proton leak in isolated mitochondria. Oxidative stress was measured by assessing activity and/or expression levels of Nrf1, Sod1, Sod2, catalase and 8-OHdG.
RESULTS When challenged with AMLN diet for 12 wk, ob/ob and FATZO mice developed steatohepatitis in the presence of obesity and hyperinsulinemia. NASH development was associated with hepatic mitochondrial abnormalities, similar to those previously observed in humans, including mitochondrial accumulation and increased proton leak. AMLN diet also resulted in increased numbers of fragmented mitochondria in both strains of mice. Despite similar mitochondrial phenotypes, we found that ob/ob mice developed more advanced hepatic fibrosis. Activity of superoxide dismutase (SOD) was increased in ob/ob AMLN mice, whereas FATZO mice displayed increased catalase activity, irrespective of diet. Furthermore, 8-OHdG, a marker of oxidative DNA damage, was significantly increased in ob/ob AMLN mice compared to FATZO AMLN mice. Therefore, antioxidant capacity reflected as the ratio of catalase:SOD activity was similar between FATZO and C57BL6J control mice, but significantly perturbed in ob/ob mice.
CONCLUSION Oxidative stress, and/or the capacity to compensate for increased oxidative stress, in the setting of mitochondrial dysfunction, is a key factor for development of hepatic injury and fibrosis in these mouse models.
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Affiliation(s)
- Michelle L Boland
- Cardiovascular and Metabolic Diseases, MedImmune LLC, Gaithersburg, MD 20878, United States
| | - Stephanie Oldham
- Cardiovascular and Metabolic Diseases, MedImmune LLC, Gaithersburg, MD 20878, United States
| | - Brandon B Boland
- Cardiovascular and Metabolic Diseases, MedImmune LLC, Gaithersburg, MD 20878, United States
| | - Sarah Will
- Cardiovascular and Metabolic Diseases, MedImmune LLC, Gaithersburg, MD 20878, United States
| | | | - Silvia Guionaud
- Pathology, Drug Safety and Metabolism, IMED Biotech Unit, AstraZeneca, Cambridge CB22 3AT, United Kingdom
| | - Christopher J Rhodes
- Cardiovascular and Metabolic Diseases, MedImmune LLC, Gaithersburg, MD 20878, United States
| | - James L Trevaskis
- Cardiovascular and Metabolic Diseases, MedImmune LLC, Gaithersburg, MD 20878, United States
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