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Mori H, Peterson SK, Simmermon RC, Overmyer KA, Nishii A, Paulsson E, Li Z, Jen A, Uranga RM, Maung JN, Yacawych WT, Lewis KT, Schill RL, Hetrick T, Seino R, Inoki K, Coon JJ, MacDougald OA. Scd1 and monounsaturated lipids are required for autophagy and survival of adipocytes. Mol Metab 2024; 83:101916. [PMID: 38492843 PMCID: PMC10975504 DOI: 10.1016/j.molmet.2024.101916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Revised: 02/29/2024] [Accepted: 03/11/2024] [Indexed: 03/18/2024] Open
Abstract
OBJECTIVE Exposure of adipocytes to 'cool' temperatures often found in the periphery of the body induces expression of Stearoyl-CoA Desaturase-1 (Scd1), an enzyme that converts saturated fatty acids to monounsaturated fatty acids. The goal of this study is to further investigate the roles of Scd in adipocytes. METHOD In this study, we employed Scd1 knockout cells and mouse models, along with pharmacological Scd1 inhibition to dissect the enzyme's function in adipocyte physiology. RESULTS Our study reveals that production of monounsaturated lipids by Scd1 is necessary for fusion of autophagosomes to lysosomes and that with a Scd1-deficiency, autophagosomes accumulate. In addition, Scd1-deficiency impairs lysosomal and autolysosomal acidification resulting in vacuole accumulation and eventual cell death. Blocking autophagosome formation or supplementation with monounsaturated fatty acids maintains vitality of Scd1-deficient adipocytes. CONCLUSION This study demonstrates the indispensable role of Scd1 in adipocyte survival, with its inhibition in vivo triggering autophagy-dependent cell death and its depletion in vivo leading to the loss of bone marrow adipocytes.
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Affiliation(s)
- Hiroyuki Mori
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA.
| | - Sydney K Peterson
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Rachel C Simmermon
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Katherine A Overmyer
- Morgridge Institute for Research, Madison, WI, USA; National Center for Quantitative Biology of Complex Systems, Madison, WI, USA
| | - Akira Nishii
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Emma Paulsson
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Ziru Li
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Annie Jen
- Department of Biomolecular Chemistry, University of Wisconsin, Madison, WI, USA; Department of Chemistry, University of Wisconsin, Madison, WI, USA
| | - Romina M Uranga
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Jessica N Maung
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Warren T Yacawych
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Kenneth T Lewis
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Rebecca L Schill
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Taryn Hetrick
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Ryo Seino
- Dojindo Molecular Technologies, Inc., Rockville, MD, USA
| | - Ken Inoki
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Joshua J Coon
- Morgridge Institute for Research, Madison, WI, USA; National Center for Quantitative Biology of Complex Systems, Madison, WI, USA; Department of Biomolecular Chemistry, University of Wisconsin, Madison, WI, USA; Department of Chemistry, University of Wisconsin, Madison, WI, USA
| | - Ormond A MacDougald
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA; Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA.
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Mori H, Peterson SK, Simmermon R, Overmyer KA, Nishii A, Paulsson E, Li Z, Jen A, Uranga RM, Maung J, Yacawych WT, Lewis KT, Schill RL, Hetrick T, Seino R, Inoki K, Coon JJ, MacDougald OA. SCD1 and monounsaturated lipids are required for autophagy and survival of adipocytes. bioRxiv 2023:2023.10.27.564376. [PMID: 37961537 PMCID: PMC10634865 DOI: 10.1101/2023.10.27.564376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Exposure of adipocytes to 'cool' temperatures often found in the periphery of the body induces expression of Stearoyl-CoA Desaturase-1 (SCD1), an enzyme that converts saturated fatty acids to monounsaturated fatty acids. In this study, we employed Scd1 knockout cells and mouse models, along with pharmacological SCD1 inhibition, to investigate further the roles of SCD1 in adipocytes. Our study reveals that production of monounsaturated lipids by SCD1 is necessary for fusion of autophagosomes to lysosomes and that with a SCD1-deficiency, autophagosomes accumulate. In addition, SCD1-deficiency impairs lysosomal and autolysosomal acidification resulting in vacuole accumulation and eventual cell death. Blocking autophagosome formation or supplementation with monounsaturated fatty acids maintains vitality of SCD1-deficient adipocytes. Taken together, our results demonstrate that in vitro inhibition of SCD1 in adipocytes leads to autophagy-dependent cell death, and in vivo depletion leads to loss of bone marrow adipocytes.
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Lewis KT, Oles LR, MacDougald OA. Tetracycline response element driven Cre causes ectopic recombinase activity independent of transactivator element. Mol Metab 2022; 61:101501. [PMID: 35452876 PMCID: PMC9170755 DOI: 10.1016/j.molmet.2022.101501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 04/06/2022] [Accepted: 04/14/2022] [Indexed: 12/03/2022] Open
Abstract
OBJECTIVE Tamoxifen is widely used for inducible Cre-LoxP systems but has several undesirable side effects for researchers investigating metabolism or energy balance, including weight loss, lipoatrophy, and drug incorporation into lipid stores. For this reason, we sought to determine whether a doxycycline-inducible system would be more advantageous for adipocyte-specific Cre mouse models, but serendipitously discovered widespread ectopic tetracycline response element Cre (TRE-Cre) recombinase activity. METHODS Adipocyte-specific tamoxifen- and doxycycline-inducible Cre mice were crossed to fluorescent Cre reporter mice and visualized by confocal microscopy to assess efficiency and background activity. TRE-Cre mice were crossed to stop-floxed diphtheria toxin mice to selectively ablate cells with background Cre activity. RESULTS Tamoxifen- and doxycycline-inducible systems performed similarly in adipose tissues, but ectopic Cre recombination was evident in numerous other cell types of the latter, most notably neurons. The source of ectopic Cre activity was isolated to the TRE-Cre transgene, driven by the pTet (tetO7) tetracycline-inducible promoter. Ablation of cells with ectopic recombination in mice led to stunted growth, diminished survival, and reduced brain mass. CONCLUSIONS These results indicate that tamoxifen- and doxycycline-inducible adipocyte-specific Cre mouse models are similarly efficient, but the TRE-Cre component of the latter is inherently leaky. TRE-Cre background activity is especially pronounced in the brain and peripheral nerve fibers, and selective ablation of these cells impairs mouse development and survival. Caution should be taken when pairing TRE-Cre with floxed alleles that have defined roles in neural function, and additional controls should be included when using this model system.
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Affiliation(s)
- Kenneth T Lewis
- University of Michigan Medical School, Department of Molecular & Integrative Physiology, Ann Arbor, MI, USA
| | - Lily R Oles
- University of Michigan Medical School, Department of Molecular & Integrative Physiology, Ann Arbor, MI, USA
| | - Ormond A MacDougald
- University of Michigan Medical School, Department of Molecular & Integrative Physiology, Ann Arbor, MI, USA; University of Michigan Medical School, Department of Internal Medicine, Ann Arbor, MI, USA.
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Li Z, Bowers E, Zhu J, Yu H, Hardij J, Bagchi DP, Mori H, Lewis KT, Granger K, Schill RL, Romanelli SM, Abrishami S, Hankenson KD, Singer K, Rosen CJ, MacDougald OA. Lipolysis of bone marrow adipocytes is required to fuel bone and the marrow niche during energy deficits. eLife 2022; 11:e78496. [PMID: 35731039 PMCID: PMC9273217 DOI: 10.7554/elife.78496] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 06/21/2022] [Indexed: 11/13/2022] Open
Abstract
To investigate roles for bone marrow adipocyte (BMAd) lipolysis in bone homeostasis, we created a BMAd-specific Cre mouse model in which we knocked out adipose triglyceride lipase (ATGL, Pnpla2 gene). BMAd-Pnpla2-/- mice have impaired BMAd lipolysis, and increased size and number of BMAds at baseline. Although energy from BMAd lipid stores is largely dispensable when mice are fed ad libitum, BMAd lipolysis is necessary to maintain myelopoiesis and bone mass under caloric restriction. BMAd-specific Pnpla2 deficiency compounds the effects of caloric restriction on loss of trabecular bone in male mice, likely due to impaired osteoblast expression of collagen genes and reduced osteoid synthesis. RNA sequencing analysis of bone marrow adipose tissue reveals that caloric restriction induces dramatic elevations in extracellular matrix organization and skeletal development genes, and energy from BMAd is required for these adaptations. BMAd-derived energy supply is also required for bone regeneration upon injury, and maintenance of bone mass with cold exposure.
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Affiliation(s)
- Ziru Li
- University of Michigan Medical School, Department of Molecular & Integrative PhysiologyAnn ArborUnited States
| | - Emily Bowers
- University of Michigan Medical School, Department of PediatricsAnn ArborUnited States
| | - Junxiong Zhu
- Department of Orthopedic Surgery, University of Michigan Medical SchoolAnn ArborUnited States
- Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of MedicineHangzhouChina
| | - Hui Yu
- University of Michigan Medical School, Department of Molecular & Integrative PhysiologyAnn ArborUnited States
| | - Julie Hardij
- University of Michigan Medical School, Department of Molecular & Integrative PhysiologyAnn ArborUnited States
| | - Devika P Bagchi
- University of Michigan Medical School, Department of Molecular & Integrative PhysiologyAnn ArborUnited States
| | - Hiroyuki Mori
- University of Michigan Medical School, Department of Molecular & Integrative PhysiologyAnn ArborUnited States
| | - Kenneth T Lewis
- University of Michigan Medical School, Department of Molecular & Integrative PhysiologyAnn ArborUnited States
| | - Katrina Granger
- University of Michigan Medical School, Department of Molecular & Integrative PhysiologyAnn ArborUnited States
| | - Rebecca L Schill
- University of Michigan Medical School, Department of Molecular & Integrative PhysiologyAnn ArborUnited States
| | - Steven M Romanelli
- University of Michigan Medical School, Department of Molecular & Integrative PhysiologyAnn ArborUnited States
| | - Simin Abrishami
- University of Michigan Medical School, Department of PediatricsAnn ArborUnited States
| | - Kurt D Hankenson
- Department of Orthopedic Surgery, University of Michigan Medical SchoolAnn ArborUnited States
| | - Kanakadurga Singer
- University of Michigan Medical School, Department of Molecular & Integrative PhysiologyAnn ArborUnited States
- University of Michigan Medical School, Department of PediatricsAnn ArborUnited States
| | | | - Ormond A MacDougald
- University of Michigan Medical School, Department of Molecular & Integrative PhysiologyAnn ArborUnited States
- University of Michigan Medical School, Department of Internal MedicineAnn ArborUnited States
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Romanelli SM, Lewis KT, Nishii A, Rupp AC, Li Z, Mori H, Schill RL, Learman BS, Rhodes CJ, MacDougald OA. BAd-CRISPR: Inducible gene knockout in interscapular brown adipose tissue of adult mice. J Biol Chem 2021; 297:101402. [PMID: 34774798 PMCID: PMC8661024 DOI: 10.1016/j.jbc.2021.101402] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 10/26/2021] [Accepted: 11/09/2021] [Indexed: 12/26/2022] Open
Abstract
CRISPR/Cas9 has enabled inducible gene knockout in numerous tissues; however, its use has not been reported in brown adipose tissue (BAT). Here, we developed the brown adipocyte CRISPR (BAd-CRISPR) methodology to rapidly interrogate the function of one or multiple genes. With BAd-CRISPR, an adeno-associated virus (AAV8) expressing a single guide RNA (sgRNA) is administered directly to BAT of mice expressing Cas9 in brown adipocytes. We show that the local administration of AAV8-sgRNA to interscapular BAT of adult mice robustly transduced brown adipocytes and ablated expression of adiponectin, adipose triglyceride lipase, fatty acid synthase, perilipin 1, or stearoyl-CoA desaturase 1 by >90%. Administration of multiple AAV8 sgRNAs led to simultaneous knockout of up to three genes. BAd-CRISPR induced frameshift mutations and suppressed target gene mRNA expression but did not lead to substantial accumulation of off-target mutations in BAT. We used BAd-CRISPR to create an inducible uncoupling protein 1 (Ucp1) knockout mouse to assess the effects of UCP1 loss on adaptive thermogenesis in adult mice. Inducible Ucp1 knockout did not alter core body temperature; however, BAd-CRISPR Ucp1 mice had elevated circulating concentrations of fibroblast growth factor 21 and changes in BAT gene expression consistent with heat production through increased peroxisomal lipid oxidation. Other molecular adaptations predict additional cellular inefficiencies with an increase in both protein synthesis and turnover, and mitochondria with reduced reliance on mitochondrial-encoded gene expression and increased expression of nuclear-encoded mitochondrial genes. These data suggest that BAd-CRISPR is an efficient tool to speed discoveries in adipose tissue biology.
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Affiliation(s)
- Steven M Romanelli
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Kenneth T Lewis
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Akira Nishii
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Alan C Rupp
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Ziru Li
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Hiroyuki Mori
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Rebecca L Schill
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Brian S Learman
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Christopher J Rhodes
- Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, Maryland, USA
| | - Ormond A MacDougald
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA; Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, USA.
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Corsa CAS, Walsh CM, Bagchi DP, Foss Freitas MC, Li Z, Hardij J, Granger K, Mori H, Schill RL, Lewis KT, Maung JN, Azaria RD, Rothberg AE, Oral EA, MacDougald OA. Adipocyte-Specific Deletion of Lamin A/C Largely Models Human Familial Partial Lipodystrophy Type 2. Diabetes 2021; 70:1970-1984. [PMID: 34088712 PMCID: PMC8576431 DOI: 10.2337/db20-1001] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 05/25/2021] [Indexed: 11/13/2022]
Abstract
Mechanisms by which autosomal recessive mutations in Lmna cause familial partial lipodystrophy type 2 (FPLD2) are poorly understood. To investigate the function of lamin A/C in adipose tissue, we created mice with an adipocyte-specific loss of Lmna (Lmna ADKO). Although Lmna ADKO mice develop and maintain adipose tissues in early postnatal life, they show a striking and progressive loss of white and brown adipose tissues as they approach sexual maturity. Lmna ADKO mice exhibit surprisingly mild metabolic dysfunction on a chow diet, but on a high-fat diet they share many characteristics of FPLD2 including hyperglycemia, hepatic steatosis, hyperinsulinemia, and almost undetectable circulating adiponectin and leptin. Whereas Lmna ADKO mice have reduced regulated and constitutive bone marrow adipose tissue with a concomitant increase in cortical bone, FPLD2 patients have reduced bone mass and bone mineral density compared with controls. In cell culture models of Lmna deficiency, mesenchymal precursors undergo adipogenesis without impairment, whereas fully differentiated adipocytes have increased lipolytic responses to adrenergic stimuli. Lmna ADKO mice faithfully reproduce many characteristics of FPLD2 and thus provide a unique animal model to investigate mechanisms underlying Lmna-dependent loss of adipose tissues.
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Affiliation(s)
- Callie A S Corsa
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI
| | - Carolyn M Walsh
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI
| | - Devika P Bagchi
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI
| | - Maria C Foss Freitas
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, MI
| | - Ziru Li
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI
| | - Julie Hardij
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI
| | - Katrina Granger
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI
| | - Hiroyuki Mori
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI
| | - Rebecca L Schill
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI
| | - Kenneth T Lewis
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI
| | - Jessica N Maung
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI
| | - Ruth D Azaria
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI
| | - Amy E Rothberg
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, MI
| | - Elif A Oral
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, MI
| | - Ormond A MacDougald
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, MI
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Bagchi DP, Li Z, Corsa CA, Hardij J, Mori H, Learman BS, Lewis KT, Schill RL, Romanelli SM, MacDougald OA. Wntless regulates lipogenic gene expression in adipocytes and protects against diet-induced metabolic dysfunction. Mol Metab 2020; 39:100992. [PMID: 32325263 PMCID: PMC7264081 DOI: 10.1016/j.molmet.2020.100992] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 03/27/2020] [Accepted: 04/02/2020] [Indexed: 02/08/2023] Open
Abstract
OBJECTIVE Obesity is a key risk factor for many secondary chronic illnesses, including type 2 diabetes and cardiovascular disease. Canonical Wnt/β-catenin signaling is established as an important endogenous inhibitor of adipogenesis. This pathway is operative in mature adipocytes; however, its roles in this context remain unclear due to complexities of Wnt signaling and differences in experimental models. In this study, we used novel cultured cell and mouse models to investigate functional roles of Wnts secreted from adipocytes. METHODS We generated adipocyte-specific Wntless (Wls) knockout mice and cultured cell models to investigate molecular and metabolic consequences of disrupting Wnt secretion from mature adipocytes. To characterize Wls-deficient cultured adipocytes, we evaluated the expression of Wnt target and lipogenic genes and the downstream functional effects on carbohydrate and lipid metabolism. We also investigated the impact of adipocyte-specific Wls deletion on adipose tissues and global glucose metabolism in mice fed normal chow or high-fat diets. RESULTS Many aspects of the Wnt signaling apparatus are expressed and operative in mature adipocytes, including the Wnt chaperone Wntless. Deletion of Wntless in cultured adipocytes results in the inhibition of de novo lipogenesis and lipid monounsaturation, likely through repression of Srebf1 (SREBP1c) and Mlxipl (ChREBP) and impaired cleavage of immature SREBP1c into its active form. Adipocyte-specific Wls knockout mice (Wls-/-) have lipogenic gene expression in adipose tissues and isolated adipocytes similar to that of controls when fed a normal chow diet. However, closer investigation reveals that a subset of Wnts and downstream signaling targets are upregulated within stromal-vascular cells of Wls-/- mice, suggesting that adipose tissues defend loss of Wnt secretion from adipocytes. Interestingly, this compensation is lost with long-term high-fat diet challenges. Thus, after six months of a high-fat diet, Wls-/- mice are characterized by decreased adipocyte lipogenic gene expression, reduced visceral adiposity, and improved glucose homeostasis. CONCLUSIONS Taken together, these studies demonstrate that adipocyte-derived Wnts regulate de novo lipogenesis and lipid desaturation and coordinate the expression of lipogenic genes in adipose tissues. In addition, we report that Wnt signaling within adipose tissues is defended, such that a loss of Wnt secretion from adipocytes is sensed and compensated for by neighboring stromal-vascular cells. With chronic overnutrition, this compensatory mechanism is lost, revealing that Wls-/- mice are resistant to diet-induced obesity, adipocyte hypertrophy, and metabolic dysfunction.
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Affiliation(s)
- Devika P Bagchi
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA.
| | - Ziru Li
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA.
| | - Callie A Corsa
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA.
| | - Julie Hardij
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA.
| | - Hiroyuki Mori
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA.
| | - Brian S Learman
- Department of Microbiology and Immunology, University of Buffalo, Buffalo, NY, USA.
| | - Kenneth T Lewis
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA.
| | - Rebecca L Schill
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA.
| | - Steven M Romanelli
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA.
| | - Ormond A MacDougald
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA; Division of Metabolism, Endocrinology, and Diabetes, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA.
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Naik AR, Kuhn ER, Lewis KT, Kokotovich KM, Maddipati KR, Chen X, Hörber JHK, Taatjes DJ, Potoff JJ, Jena BP. Self-Assembly and Biogenesis of the Cellular Membrane are Dictated by Membrane Stretch and Composition. J Phys Chem B 2019; 123:6997-7005. [PMID: 31322890 DOI: 10.1021/acs.jpcb.9b04769] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The cell plasma membrane is a highly dynamic organelle governing a wide range of cellular activities including ion transport, secretion, cell division, growth, and development. The fundamental process involved in the addition of new membranes to pre-existing plasma membranes, however, is unclear. Here, we report, using biophysical, morphological, biochemical, and molecular dynamic simulations, the selective incorporation of proteins and lipids from the cytosol into the cell plasma membrane dictated by membrane stretch and composition. Stretching of the cell membrane as a consequence of volume increase following incubation in a hypotonic solution and results in the incorporation of cytosolic proteins and lipids into the existing plasma membrane. Molecular dynamic simulations further confirm that increased membrane stretch results in the rapid insertion of lipids into the existing plasma membrane. Similarly, depletion of cholesterol from the cell plasma membrane selectively alters the incorporation of lipids into the membrane.
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Affiliation(s)
| | | | | | | | | | | | - J H K Hörber
- Department of Physics , University of Bristol , Bristol BS8 1TD , U.K
| | - Douglas J Taatjes
- Department of Pathology and Laboratory Medicine, Microscopy Imaging Center , University of Vermont College of Medicine , Burlington , Vermont 05405 , United States
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Li Z, Hardij J, Evers SS, Hutch CR, Choi SM, Shao Y, Learman BS, Lewis KT, Schill RL, Mori H, Bagchi DP, Romanelli SM, Kim KS, Bowers E, Griffin C, Seeley RJ, Singer K, Sandoval DA, Rosen CJ, MacDougald OA. G-CSF partially mediates effects of sleeve gastrectomy on the bone marrow niche. J Clin Invest 2019; 129:2404-2416. [PMID: 31063988 PMCID: PMC6546463 DOI: 10.1172/jci126173] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 03/05/2019] [Indexed: 01/26/2023] Open
Abstract
Bariatric surgeries are integral to the management of obesity and its metabolic complications. However, these surgeries cause bone loss and increase fracture risk through poorly understood mechanisms. In a mouse model, vertical sleeve gastrectomy (VSG) caused trabecular and cortical bone loss that was independent of sex, body weight, and diet, and this loss was characterized by impaired osteoid mineralization and bone formation. VSG had a profound effect on the bone marrow niche, with rapid loss of marrow adipose tissue, and expansion of myeloid cellularity, leading to increased circulating neutrophils. Following VSG, circulating granulocyte-colony stimulating factor (G-CSF) was increased in mice, and was transiently elevated in a longitudinal study of humans. Elevation of G-CSF was found to recapitulate many effects of VSG on bone and the marrow niche. In addition to stimulatory effects of G-CSF on myelopoiesis, endogenous G-CSF suppressed development of marrow adipocytes and hindered accrual of peak cortical and trabecular bone. Effects of VSG on induction of neutrophils and depletion of marrow adiposity were reduced in mice deficient for G-CSF; however, bone mass was not influenced. Although not a primary mechanism for bone loss with VSG, G-CSF plays an intermediary role for effects of VSG on the bone marrow niche.
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Affiliation(s)
- Ziru Li
- Department of Molecular & Integrative Physiology
| | - Julie Hardij
- Department of Molecular & Integrative Physiology
| | | | | | | | | | | | | | | | | | | | | | | | - Emily Bowers
- Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Cameron Griffin
- Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | | | - Kanakadurga Singer
- Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor, Michigan, USA
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Naik AR, Pernal S, Lewis KT, Wu Y, Wu H, Carruthers NJ, Stemmer P, Jena BP. Human Skeletal Muscle‐on‐a‐Chip. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.lb645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | - Yaobin Wu
- ChemistryHong Kong UniversityHong KongPeople's Republic of China
| | - Hongkai Wu
- ChemistryHong Kong UniversityHong KongPeople's Republic of China
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11
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Naik AR, Pernal S, Lewis KT, Wu Y, Wu H, Carruthers NJ, Stemmer PM, Jena BP. Human Skeletal Muscle Cells on Engineered 3D Platform Express Key Growth and Developmental Proteins. ACS Biomater Sci Eng 2019; 5:970-976. [PMID: 33405788 DOI: 10.1021/acsbiomaterials.8b01338] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Current approaches in regenerative medicine to develop human skeletal muscle replicating native tissue for engrafts and high-throughput drug screening and gene therapy are still in their infancy and have not proven to recapitulate the behavior and regulatory processes present in endogenous skeletal muscle tissue. This stems at least in part from the lack of a comprehensive understanding of the emergent properties of in vitro skeletal muscle growth and development. To address this gap in our current knowledge, we have developed a stretchable micropatterned 3D human skeletal muscle platform that recapitulates organized and parallel growth of muscle cells and fibers as opposed to the randomly oriented cells growth on a 2D glass surface. Mass spectrometry of the muscle cells growing on the 3D platform express key myogenic proteins such as myoferlin for myoblast fusion required in the formation of muscle tissue, and proteins involved in mitochondrial health and biogenesis, in contrast to cells growing on 2D glass surface. These results demonstrate that the engineered human muscle cells grown on the 3D platform holds great promise to further establish the emergent properties of in vitro skeletal muscle growth and development for a wide range of biomedical applications.
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Affiliation(s)
| | | | | | - Yaobin Wu
- Department of Chemistry, Hong Kong University of Science & Technology, Hong Kong, China
| | - Hongkai Wu
- Department of Chemistry, Hong Kong University of Science & Technology, Hong Kong, China
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12
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Abstract
Culturing bone marrow stromal cells on 3D silk scaffolds supports their proliferation and adipogenesis, while minimizing the activation of inflammatory pathways. Therefore, differentiation of bone marrow adipocytes in 3D culture might provide a more representative model for the study of bone marrow adipose tissue than is offered by traditional 2D cell cultures.
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Affiliation(s)
- Kenneth T Lewis
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Ormond A MacDougald
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
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13
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Naik AR, Kuhn ER, Lewis KT, Kokotovich KM, Maddipati KR, Chen X, Hörber H, Taatjes DJ, Potoff JJ, Jena BP. Mechanism of Membrane Biogenesis. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.671.11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Eric R. Kuhn
- Department of PhysiologySchool of MedicineWayne State UniversityDetroitMI
| | - Kenneth T. Lewis
- Department of PhysiologySchool of MedicineWayne State UniversityDetroitMI
| | | | - Krishna R. Maddipati
- Department of Pathology, Lipidomics Core FacilityWayne State UniversityDetroitMI
| | - Xuequn Chen
- Department of PhysiologySchool of MedicineWayne State UniversityDetroitMI
| | - Heinrich Hörber
- Department of PhysicsUniversity of BristolBristolUnited Kingdom
| | - Douglas J. Taatjes
- Department of Pathology and Laboratory MedicineMicroscopy Imaging CenterUniversity of Vermont College of MedicineBurlingtonVT
| | - Jeffrey J. Potoff
- Department of Chemical Engineering & Materials ScienceCollege of EngineeringWayne State UniversityDetroitMI
| | - Bhanu P. Jena
- Department of PhysiologySchool of MedicineWayne State UniversityDetroitMI
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14
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Lewis KT, Naik AR, Laha SS, Wang S, Mao G, Kuhn E, Jena BP. Secretion induces cell pH dynamics impacting assembly-disassembly of the fusion protein complex: A combined fluorescence and atomic force microscopy study. Semin Cell Dev Biol 2018; 73:57-63. [DOI: 10.1016/j.semcdb.2017.08.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 07/28/2017] [Accepted: 08/01/2017] [Indexed: 11/25/2022]
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Lewis KT, Maddipati KR, Naik AR, Jena BP. Unique Lipid Chemistry of Synaptic Vesicle and Synaptosome Membrane Revealed Using Mass Spectrometry. ACS Chem Neurosci 2017; 8:1163-1169. [PMID: 28244738 DOI: 10.1021/acschemneuro.7b00030] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Synaptic vesicles measuring 30-50 nm in diameter containing neurotransmitters either completely collapse at the presynaptic membrane or dock and transiently fuse at the base of specialized 15 nm cup-shaped lipoprotein structures called porosomes at the presynaptic membrane of synaptosomes to release neurotransmitters. Recent study reports the unique composition of major lipids associated with neuronal porosomes. Given that lipids greatly influence the association and functions of membrane proteins, differences in lipid composition of synaptic vesicle and the synaptosome membrane was hypothesized. To test this hypothesis, the lipidome of isolated synaptosome, synaptosome membrane, and synaptic vesicle preparation were determined by using mass spectrometry in the current study. Results from the study demonstrate the enriched presence of triacyl glycerols and sphingomyelins in synaptic vesicles, as opposed to the enriched presence of phospholipids in the synaptosome membrane fraction, reflecting on the tight regulation of nerve cells in compartmentalization of membrane lipids at the nerve terminal.
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Affiliation(s)
- Kenneth T. Lewis
- Department
of Physiology and ‡Department of Pathology, Lipidomics Core Facility, Wayne State University School of Medicine, Detroit, Michigan 48201, United States
| | - Krishna R. Maddipati
- Department
of Physiology and ‡Department of Pathology, Lipidomics Core Facility, Wayne State University School of Medicine, Detroit, Michigan 48201, United States
| | - Akshata R. Naik
- Department
of Physiology and ‡Department of Pathology, Lipidomics Core Facility, Wayne State University School of Medicine, Detroit, Michigan 48201, United States
| | - Bhanu P. Jena
- Department
of Physiology and ‡Department of Pathology, Lipidomics Core Facility, Wayne State University School of Medicine, Detroit, Michigan 48201, United States
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16
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Abstract
In the past 50 years, isolated blood platelets have had restricted use in wound healing, cancer therapy, and organ and tissue transplant, to name a few. The major obstacle for its unrestricted use has been, among others, the presence of ultrahigh concentrations of growth factors and the presence of both pro-angiogenic and anti-angiogenic proteins. To overcome this problem requires the isolation and separation of the membrane bound secretory vesicles containing the different factors. In the current study, high-resolution imaging of isolated secretory vesicles from human platelets using atomic force microscopy (AFM) and mass spectrometry enabled characterization of the remaining vesicles size and composition following their immunoseparation. The remaining vesicles obtained following osmotic lysis, when subjected to immunoseparation employing antibody to different vesicle-associated membrane proteins (VAMPs), demonstrate for the first time that VAMP-3-, VAMP-7-, and VAMP-8-specific vesicles each possesses distinct size range and composition. These results provide a window into our understanding of the heterogeneous population of vesicles in human platelets and their stability following both physical manipulation using AFM and osmotic lysis of the platelet. This study further provides a platform for isolation and the detailed characterization of platelet granules, with promise for their future use in therapy. Additionally, results from the study demonstrate that secretory vesicles of different size found in cells reflect their unique and specialized composition and function.
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Affiliation(s)
- Bhanu P Jena
- Department of Physiology, School of Medicine, ‡Department of Chemical Engineering & Materials Science, College of Engineering, and §Institute of Environment Health Sciences, Wayne State University , Detroit, Michigan 48201, United States
| | - Paul M Stemmer
- Department of Physiology, School of Medicine, ‡Department of Chemical Engineering & Materials Science, College of Engineering, and §Institute of Environment Health Sciences, Wayne State University , Detroit, Michigan 48201, United States
| | - Sunxi Wang
- Department of Physiology, School of Medicine, ‡Department of Chemical Engineering & Materials Science, College of Engineering, and §Institute of Environment Health Sciences, Wayne State University , Detroit, Michigan 48201, United States
| | - Guangzhao Mao
- Department of Physiology, School of Medicine, ‡Department of Chemical Engineering & Materials Science, College of Engineering, and §Institute of Environment Health Sciences, Wayne State University , Detroit, Michigan 48201, United States
| | - Kenneth T Lewis
- Department of Physiology, School of Medicine, ‡Department of Chemical Engineering & Materials Science, College of Engineering, and §Institute of Environment Health Sciences, Wayne State University , Detroit, Michigan 48201, United States
| | - Daniel A Walz
- Department of Physiology, School of Medicine, ‡Department of Chemical Engineering & Materials Science, College of Engineering, and §Institute of Environment Health Sciences, Wayne State University , Detroit, Michigan 48201, United States
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17
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Arachchige MP, Laha SS, Naik AR, Lewis KT, Naik R, Jena BP. Functionalized nanoparticles enable tracking the rapid entry and release of doxorubicin in human pancreatic cancer cells. Micron 2017; 92:25-31. [DOI: 10.1016/j.micron.2016.10.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 10/24/2016] [Accepted: 10/25/2016] [Indexed: 10/20/2022]
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18
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Abstract
Supramolecular cup-shaped lipoprotein structures called porosomes embedded in the cell plasma membrane mediate fractional release of intravesicular contents from cells during secretion. The presence of porosomes, have been documented in many cell types including neurons, acinar cells of the exocrine pancreas, GH-secreting cells of the pituitary, and insulin-secreting pancreatic β-cells. Functional reconstitution of porosomes into artificial lipid membranes, have also been accomplished. Earlier studies on mouse insulin-secreting Min6 cells report 100-nm porosome complexes composed of nearly 30 proteins. In the current study, porosomes have been functionally reconstituted for the first time in live cells. Isolated Min6 porosomes reconstituted into live Min6 cells demonstrate augmented levels of porosome proteins and a consequent increase in the potency and efficacy of glucose-stimulated insulin release. Elevated glucose-stimulated insulin secretion 48 hours after reconstitution, reflects on the remarkable stability and viability of reconstituted porosomes, documenting the functional reconstitution of native porosomes in live cells. These results, establish a new paradigm in porosome-mediated insulin secretion in β-cells.
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Affiliation(s)
- Akshata R Naik
- Department of Physiology (A.R.N., S.P.K., K.T.L., B.P.J.), Wayne State University School of Medicine, Detroit, Michigan 48201; and Department of Pathology and Laboratory Medicine (D.J.T.), Microscopy Imaging Center, University of Vermont College of Medicine, Burlington, Vermont 05405
| | - Sanjana P Kulkarni
- Department of Physiology (A.R.N., S.P.K., K.T.L., B.P.J.), Wayne State University School of Medicine, Detroit, Michigan 48201; and Department of Pathology and Laboratory Medicine (D.J.T.), Microscopy Imaging Center, University of Vermont College of Medicine, Burlington, Vermont 05405
| | - Kenneth T Lewis
- Department of Physiology (A.R.N., S.P.K., K.T.L., B.P.J.), Wayne State University School of Medicine, Detroit, Michigan 48201; and Department of Pathology and Laboratory Medicine (D.J.T.), Microscopy Imaging Center, University of Vermont College of Medicine, Burlington, Vermont 05405
| | - Douglas J Taatjes
- Department of Physiology (A.R.N., S.P.K., K.T.L., B.P.J.), Wayne State University School of Medicine, Detroit, Michigan 48201; and Department of Pathology and Laboratory Medicine (D.J.T.), Microscopy Imaging Center, University of Vermont College of Medicine, Burlington, Vermont 05405
| | - Bhanu P Jena
- Department of Physiology (A.R.N., S.P.K., K.T.L., B.P.J.), Wayne State University School of Medicine, Detroit, Michigan 48201; and Department of Pathology and Laboratory Medicine (D.J.T.), Microscopy Imaging Center, University of Vermont College of Medicine, Burlington, Vermont 05405
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19
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Abstract
Cup-shaped secretory portals at the cell plasma membrane called porosomes mediate the precision release of intravesicular material from cells. Membrane-bound secretory vesicles transiently dock and fuse at the base of porosomes facing the cytosol to expel pressurized intravesicular contents from the cell during secretion. The structure, isolation, composition, and functional reconstitution of the neuronal porosome complex have greatly progressed, providing a molecular understanding of its function in health and disease. Neuronal porosomes are 15 nm cup-shaped lipoprotein structures composed of nearly 40 proteins, compared to the 120 nm nuclear pore complex composed of >500 protein molecules. Membrane proteins compose the porosome complex, making it practically impossible to solve its atomic structure. However, atomic force microscopy and small-angle X-ray solution scattering studies have provided three-dimensional structural details of the native neuronal porosome at sub-nanometer resolution, providing insights into the molecular mechanism of its function. The participation of several porosome proteins previously implicated in neurotransmission and neurological disorders, further attest to the crosstalk between porosome proteins and their coordinated involvement in release of neurotransmitter at the synapse.
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Affiliation(s)
- Akshata R Naik
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Kenneth T Lewis
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Bhanu P Jena
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, USA
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20
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Rajagopal A, Kulkarni S, Lewis KT, Chen X, Maarouf A, Kelly CV, Taatjes DJ, Jena BP. Proteome of the insulin-secreting Min6 cell porosome complex: involvement of Hsp90 in its assembly and function. J Proteomics 2014; 114:83-92. [PMID: 25464371 DOI: 10.1016/j.jprot.2014.11.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 10/19/2014] [Accepted: 11/03/2014] [Indexed: 11/15/2022]
Abstract
UNLABELLED Porosomes are secretory portals located at the cell plasma membrane involved in the regulated release of intravesicular contents from cells. Porosomes have been immunoisolated from a number of cells including the exocrine pancreas and neurons, biochemically characterized, and functionally reconstituted into an artificial lipid membrane. In the current study, the proteome of the porosome complex in mouse insulinoma Min6 cells was determined, demonstrating among other proteins, the presence of 30 core proteins including the heat shock protein Hsp90. Half maximal inhibition of Hsp90 using the specific inhibitor 17-demethoxy-17-(2-prophenylamino) geldanamycin, results in the loss of proteins, including the calcium-transporting ATPase type 2C and the potassium channel subfamily K member 2 from the Min6 porosome. This loss of porosome proteins is reflected in the observed inhibition of glucose stimulated insulin release from Min6 cells exposed to the Hsp90 specific inhibitor. Results from the study implicate Hsp90 in the assembly and function of the porosome complex. BIOLOGICAL SIGNIFICANCE In the present study, the porosome proteome in the insulin-secreting mouse β-cell line Min6 has been determined. Nearly 30 core proteins including the heat shock protein Hsp90 are found to compose the Min6 porosome complex. Results from the study implicate Hsp90 in the assembly of the Min6 porosome. These new findings will facilitate understanding of the porosome assembly and its function in insulin secretion.
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Affiliation(s)
- Amulya Rajagopal
- Wayne State University School of Medicine, Department of Physiology, Detroit, MI, USA
| | - Sanjana Kulkarni
- Wayne State University School of Medicine, Department of Physiology, Detroit, MI, USA
| | - Kenneth T Lewis
- Wayne State University School of Medicine, Department of Physiology, Detroit, MI, USA
| | - Xuequn Chen
- Wayne State University School of Medicine, Department of Physiology, Detroit, MI, USA
| | - Abir Maarouf
- Wayne State University, Department of Physics and Astronomy, Detroit, MI, USA
| | - Christopher V Kelly
- Wayne State University, Department of Physics and Astronomy, Detroit, MI, USA
| | - Douglas J Taatjes
- Department of Pathology and Laboratory Medicine, Microscopy Imaging Center, University of Vermont College of Medicine, Burlington, VT 05405, USA
| | - Bhanu P Jena
- Wayne State University School of Medicine, Department of Physiology, Detroit, MI, USA; Wayne State University, Department of Physics and Astronomy, Detroit, MI, USA.
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21
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Abstract
Cup-shaped lipoprotein structures called porosomes are the universal secretory portals at the cell plasma membrane, where secretory vesicles transiently dock and fuse to release intravesicular contents. In neurons, porosomes measure ∼15 nm and are comprised of nearly 40 proteins, among them SNAREs, ion channels, the Gαo G-protein and several structural proteins. Earlier studies report the interaction of specific lipids and their influence on SNAREs, ion channels and G-protein function. Our own studies demonstrate the requirement of cholesterol for the maintenance of neuronal porosome integrity, and the influence of lipids on SNARE complex assembly. In this study, to further understand the role of lipids on porosome structure-function, the lipid composition of isolated neuronal porosome was determined using mass spectrometry. Using lipid-binding assays, the affinity of porosome-associated syntaxin-1A to various lipids was determined. Our mass spectrometry results demonstrate the presence of phosphatidylinositol phosphates (PIP's) and phosphatidic acid (PA) among other lipids, and the enriched presence of ceramide (Cer), lysophosphatidylinositol phosphates (LPIP) and diacylglycerol (DAG). Lipid binding assays demonstrate the binding of neuronal porosome to cardiolipin, and confirm its association with PIP's and PA. The ability of exogenous PA to alter protein–protein interaction and neurotransmitter release is further demonstrated from the study.
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Affiliation(s)
- Kenneth T Lewis
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI, USA
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22
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Hou X, Lewis KT, Wu Q, Wang S, Chen X, Flack A, Mao G, Taatjes DJ, Sun F, Jena BP. Proteome of the porosome complex in human airway epithelia: interaction with the cystic fibrosis transmembrane conductance regulator (CFTR). J Proteomics 2013; 96:82-91. [PMID: 24220302 DOI: 10.1016/j.jprot.2013.10.041] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Revised: 10/20/2013] [Accepted: 10/31/2013] [Indexed: 01/11/2023]
Abstract
UNLABELLED The surface of the airways is coated with a thin film of mucus composed primarily of mucin, which is under continuous motion via ciliary action. Mucin not only serves to lubricate the airways epithelia, but also functions as a trap for foreign particles and pathogens, thereby assisting in keeping the airways clean and free of particulate matter and infections. Altered mucin secretion especially increased mucin viscosity, results in mucin stagnation due to the inability of the cilia to propel them, leading to infections and diseases such as cystic fibrosis (CF). Since porosomes have been demonstrated to be the secretory portals at the cell plasma membrane in cells, their presence, structure, and composition in the mucin-secreting human airway epithelial cell line Calu-3 expressing CF transmembrane receptor (CFTR), were investigated. Atomic force microscopy (AFM) of Calu-3 cells demonstrates the presence of approximately 100nm in diameter porosome openings at the plasma membrane surface. Electron microscopy confirms the AFM results, and tandem mass spectrometry and immunoanalysis performed on isolated Calu-3 porosomes, reveal the association of CFTR with the porosome complex. These new findings will facilitate understanding of CFTR-porosome interactions influencing mucous secretion, and provide critical insights into the etiology of CF disease. BIOLOGICAL SIGNIFICANCE In the present study, the porosome proteome in human airway epithelia has been determined. The interaction between the cystic fibrosis transmembrane conductance regulator (CFTR) and the porosome complex in the human airway epithelia is further demonstrated. The possible regulation by CFTR on the quality of mucus secretion via the porosome complex at the cell plasma membrane is hypothesized. These new findings will facilitate understanding of CFTR-porosome interactions influencing mucous secretion, and provide critical insights into the etiology of CF disease.
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Affiliation(s)
- Xia Hou
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA
| | - Kenneth T Lewis
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA
| | - Qingtian Wu
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA
| | - Sunxi Wang
- Department of Chemical Engineering & Materials Science, College of Engineering, Wayne State University, MI 48202, USA
| | - Xuequn Chen
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA
| | - Amanda Flack
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA
| | - Guangzhao Mao
- Department of Chemical Engineering & Materials Science, College of Engineering, Wayne State University, MI 48202, USA
| | - Douglas J Taatjes
- Department of Pathology, Microscopy Imaging Center, University of Vermont College of Medicine, Burlington, VT 05405, USA
| | - Fei Sun
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA
| | - Bhanu P Jena
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA; Department of Chemical Engineering & Materials Science, College of Engineering, Wayne State University, MI 48202, USA.
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Kovari LC, Brunzelle JS, Lewis KT, Cho WJ, Lee JS, Taatjes DJ, Jena BP. X-ray solution structure of the native neuronal porosome-synaptic vesicle complex: Implication in neurotransmitter release. Micron 2013; 56:37-43. [PMID: 24176623 DOI: 10.1016/j.micron.2013.10.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 09/29/2013] [Accepted: 10/02/2013] [Indexed: 11/30/2022]
Abstract
Nanoportals at the cell plasma membrane called porosomes, mediate secretion from cells. In neurons porosomes are 15 nm cup-shaped lipoprotein structure composed of nearly 40 proteins. The size and complexity of the porosome has precluded determination of its atomic structure. Here we report at nanometer resolution the native 3D structure of the neuronal porosome-synaptic vesicle complex within isolated nerve terminals using small-angle X-ray solution scattering. In addition to furthering our understanding of the porosome structure, results from the study suggests the molecular mechanism involved in neurotransmitter release at the nerve terminal.
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Affiliation(s)
- Ladislau C Kovari
- Wayne State University School of Medicine, Department of Biochemistry and Molecular Biology, Detroit, MI, USA
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Lewis KT, Stiles M. Management of cat and dog bites. Am Fam Physician 1995; 52:479-85, 489-90. [PMID: 7625323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
An estimated 1 to 2 million Americans are bitten by cats and dogs each year. Most victims are children who are bitten by dogs. Dog and cat bite wounds may appear trivial, but if they are not managed appropriately, they can become infected and may result in functional impairment. Cat bite wounds on the hand have the greatest risk of infection. Pasteurella multocida, isolated in over half of all cat bite wounds and in 20 to 30 percent of dog bite wounds, can cause serious infection with severe complications. Amoxicillin-clavulanate is recommended for the outpatient treatment of dog and cat bite wounds. Tetanus immunization status and the risk of rabies infection should be routinely addressed in bite wound management.
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Affiliation(s)
- K T Lewis
- Department of Family Medicine, University of Wisconsin Medical School, USA
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Lewis KT, Bukstein DA. Parapneumonic empyema in children: diagnosis and management. Am Fam Physician 1992; 46:1443-55. [PMID: 1442463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Parapneumonic effusion can be a significant problem if it is not recognized and treated promptly. The amount of pleural fluid at presentation is usually small and may not be detected on physical examination. If pleural fluid is seen on radiographs, thoracentesis must be performed. Early, free-flowing parapneumonic effusions usually respond clinically to antibiotic therapy without the necessity of draining the pleural space. Distinguishing between exudative effusion and empyema is crucial. Failure of effusion or empyema to respond to the treatment is usually due to failure to adequately drain the pleural space or inappropriate antibiotic therapy. If chest tube drainage does not result in a lower temperature and an appropriate clinical response within a few days, further evaluation by computed tomographic scanning and surgical consultation are indicated. In patients with pleural effusion and empyema that responds poorly to medical and/or surgical therapy, underlying causes or associated debilitating disease should be excluded.
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Utt JK, Lewis KT. Using desktop publishing to enhance pharmacy publications. Am J Hosp Pharm 1988; 45:1863-4. [PMID: 3228112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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