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Bozadjieva-Kramer N, Shin JH, Li Z, Rupp AC, Miller N, Kernodle S, Lanthier N, Henry P, Seshadri N, Myronovych A, MacDougald OA, O'Rourke RW, Kohli R, Burant CF, Rothberg AE, Seeley RJ. Intestinal FGF15 regulates bile acid and cholesterol metabolism but not glucose and energy balance. JCI Insight 2024; 9:e174164. [PMID: 38587078 DOI: 10.1172/jci.insight.174164] [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] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 02/21/2024] [Indexed: 04/09/2024] Open
Abstract
Fibroblast growth factor 15/19 (FGF15/19, mouse/human ortholog) is expressed in the ileal enterocytes of the small intestine and released postprandially in response to bile acid absorption. Previous reports of FGF15-/- mice have limited our understanding of gut-specific FGF15's role in metabolism. Therefore, we studied the role of endogenous gut-derived FGF15 in bile acid, cholesterol, glucose, and energy balance. We found that circulating levels of FGF19 were reduced in individuals with obesity and comorbidities, such as type 2 diabetes and metabolic dysfunction-associated fatty liver disease. Gene expression analysis of ileal FGF15-positive cells revealed differential expression during the obesogenic state. We fed standard chow or a high-fat metabolic dysfunction-associated steatohepatitis-inducing diet to control and intestine-derived FGF15-knockout (FGF15INT-KO) mice. Control and FGF15INT-KO mice gained similar body weight and adiposity and did not show genotype-specific differences in glucose, mixed meal, pyruvate, and glycerol tolerance. FGF15INT-KO mice had increased systemic bile acid levels but decreased cholesterol levels, pointing to a primary role for gut-derived FGF15 in regulating bile acid and cholesterol metabolism when exposed to obesogenic diet. These studies show that intestinal FGF15 plays a specific role in bile acid and cholesterol metabolism regulation but is not essential for energy and glucose balance.
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Affiliation(s)
- Nadejda Bozadjieva-Kramer
- Research Service, Veterans Affairs Ann Arbor Healthcare System, Ann Arbor, Michigan, USA
- Department of Surgery and
| | | | - Ziru Li
- Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
- Center for Molecular Medicine, MaineHealth Institute for Research, Scarborough, Maine, USA
| | - Alan C Rupp
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Nicole Miller
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | | | - Nicolas Lanthier
- Hepato-Gastroenterology Department, Saint-Luc University Clinics, and
- Laboratory of Hepatology and Gastroenterology, Institute of Experimental and Clinical Research, UCLouvain, Brussels, Belgium
| | - Paulina Henry
- Pathological Anatomy Department, Institute of Pathology and Genetics, Gosselies, Belgium
| | | | | | - Ormond A MacDougald
- Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Robert W O'Rourke
- Research Service, Veterans Affairs Ann Arbor Healthcare System, Ann Arbor, Michigan, USA
- Department of Surgery and
| | - Rohit Kohli
- Division of Gastroenterology, Hepatology and Nutrition, Children's Hospital Los Angeles, Los Angeles, California, USA
| | - Charles F Burant
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Amy E Rothberg
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
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2
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Rupp AC, Tomlinson AJ, Affinati AH, Yacawych WT, Duensing AM, True C, Lindsley SR, Kirigiti MA, MacKenzie A, Polex-Wolf J, Li C, Knudsen LB, Seeley RJ, Olson DP, Kievit P, Myers MG. Suppression of food intake by Glp1r/Lepr-coexpressing neurons prevents obesity in mouse models. J Clin Invest 2023; 133:e157515. [PMID: 37581939 PMCID: PMC10541203 DOI: 10.1172/jci157515] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 08/03/2023] [Indexed: 08/17/2023] Open
Abstract
The adipose-derived hormone leptin acts via its receptor (LepRb) in the brain to control energy balance. A potentially unidentified population of GABAergic hypothalamic LepRb neurons plays key roles in the restraint of food intake and body weight by leptin. To identify markers for candidate populations of LepRb neurons in an unbiased manner, we performed single-nucleus RNA-Seq of enriched mouse hypothalamic LepRb cells, identifying several previously unrecognized populations of hypothalamic LepRb neurons. Many of these populations displayed strong conservation across species, including GABAergic Glp1r-expressing LepRb (LepRbGlp1r) neurons, which expressed more Lepr than other LepRb cell populations. Ablating Lepr from LepRbGlp1r cells provoked hyperphagic obesity without impairing energy expenditure. Similarly, improvements in energy balance caused by Lepr reactivation in GABA neurons of otherwise Lepr-null mice required Lepr expression in GABAergic Glp1r-expressing neurons. Furthermore, restoration of Glp1r expression in LepRbGlp1r neurons in otherwise Glp1r-null mice enabled food intake suppression by the GLP1R agonist, liraglutide. Thus, the conserved GABAergic LepRbGlp1r neuron population plays crucial roles in the suppression of food intake by leptin and GLP1R agonists.
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Affiliation(s)
| | | | | | - Warren T. Yacawych
- Department of Internal Medicine and
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Allison M. Duensing
- Department of Internal Medicine and
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Cadence True
- Oregon National Primate Research Center, Beaverton, Oregon, USA
| | | | | | | | | | - Chien Li
- Novo Nordisk, Copenhagen, Denmark
| | | | | | - David P. Olson
- Department of Pediatrics, University of Michigan, Ann Arbor, Michigan, USA
| | - Paul Kievit
- Oregon National Primate Research Center, Beaverton, Oregon, USA
| | - Martin G. Myers
- Department of Internal Medicine and
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
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3
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Patel AR, Frikke-Schmidt H, Sabatini PV, Rupp AC, Sandoval DA, Myers MG, Seeley RJ. Neither GLP-1 receptors nor GFRAL neurons are required for aversive or anorectic response to DON (vomitoxin). Am J Physiol Regul Integr Comp Physiol 2023; 324:R635-R644. [PMID: 36912475 PMCID: PMC10110708 DOI: 10.1152/ajpregu.00189.2022] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 03/02/2023] [Accepted: 03/02/2023] [Indexed: 03/14/2023]
Abstract
Deoxynivalenol (DON), a type B trichothecene mycotoxin contaminating grains, promotes nausea, emesis and anorexia. With DON exposure, circulating levels of intestinally derived satiation hormones, including glucagon-like peptide 1 (GLP-1) are elevated. To directly test whether GLP-1 signaling mediates the effects of DON, we examined the response of GLP-1 or GLP-1R-deficient mice to DON injection. We found comparable anorectic and conditioned taste avoidance learning responses in GLP-1/GLP-1R deficient mice compared to control littermates, suggesting that GLP-1 is not necessary for the effects of DON on food intake and visceral illness. We then used our previously published data from translating ribosome affinity purification with RNA sequencing (TRAP-seq) analysis of area postrema neurons that express the receptor for the circulating cytokine growth differentiation factor (GDF15), growth differentiation factor a-like (GFRAL). Interestingly, this analysis showed that a cell surface receptor for DON, calcium sensing receptor (CaSR), is heavily enriched in GFRAL neurons. Given that GDF15 potently reduces food intake and can cause visceral illness by signaling through GFRAL neurons, we hypothesized that DON may also signal by activating CaSR on GFRAL neurons. Indeed, circulating GDF15 levels are elevated after DON administration but both GFRAL knockout and GFRAL neuron-ablated mice exhibited similar anorectic and conditioned taste avoidance responses compared to WT littermates. Thus, GLP-1 signaling and GFRAL signaling and neurons are not required for DON-induced visceral illness or anorexia.
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Affiliation(s)
- Anita R Patel
- Neuroscience Graduate Program, University of Michigan-Ann Arbor, Ann Arbor, MI, United States
- Department of Surgery, University of Michigan-Ann Arbor, Ann Arbor, MI, United States
| | | | - Paul V Sabatini
- Department of Medicine, McGill University, Montreal, QC, Canada
| | - Alan C Rupp
- Department of Internal Medicine, University of Michigan-Ann Arbor, Ann Arbor, MI, United States
| | - Darleen A Sandoval
- Department of Pediatrics, Section of Nutrition and Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Martin G Myers
- Department of Internal Medicine, University of Michigan-Ann Arbor, Ann Arbor, MI, United States
| | - Randy J Seeley
- Department of Surgery, University of Michigan-Ann Arbor, Ann Arbor, MI, United States
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4
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Shin JH, Bozadjieva-Kramer N, Shao Y, Lyons-Abbott S, Rupp AC, Sandoval DA, Seeley RJ. The gut peptide Reg3g links the small intestine microbiome to the regulation of energy balance, glucose levels, and gut function. Cell Metab 2022; 34:1765-1778.e6. [PMID: 36240758 PMCID: PMC9633559 DOI: 10.1016/j.cmet.2022.09.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [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: 04/06/2022] [Revised: 08/12/2022] [Accepted: 09/26/2022] [Indexed: 02/08/2023]
Abstract
Changing composition of the gut microbiome is an important component of the gut adaptation to various environments, which have been implicated in various metabolic diseases including obesity and type 2 diabetes, but the mechanisms by which the microbiota influence host physiology remain contentious. Here we find that both diets high in the fermentable fiber inulin and vertical sleeve gastrectomy increase intestinal expression and circulating levels of the anti-microbial peptide Reg3g. Moreover, a number of beneficial effects of these manipulations on gut function, energy balance, and glucose regulation are absent in Reg3g knockout mice. Peripheral administration of various preparations of Reg3g improves glucose tolerance, and this effect is dependent on the putative receptor Extl3 in the pancreas. These data suggest Reg3g acts both within the lumen and as a gut hormone to link the intestinal microbiome to various aspects of host physiology that may be leveraged for novel treatment strategies.
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Affiliation(s)
- Jae Hoon Shin
- Department of Surgery, University of Michigan, Ann Arbor, MI, USA
| | - Nadejda Bozadjieva-Kramer
- Department of Surgery, University of Michigan, Ann Arbor, MI, USA; Veterans Affairs Ann Arbor Healthcare System, Research Service, Ann Arbor, MI, USA
| | - Yikai Shao
- Department of Surgery, University of Michigan, Ann Arbor, MI, USA; Center for Obesity and Metabolic Surgery, Huashan Hospital of Fudan University, Shanghai, China
| | | | - Alan C Rupp
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Darleen A Sandoval
- Department of Surgery, University of Michigan, Ann Arbor, MI, USA; Department of Pediatrics Section of Nutrition, University of Colorado School of Medicine, Aurora, CO, USA
| | - Randy J Seeley
- Department of Surgery, University of Michigan, Ann Arbor, MI, USA.
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5
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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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6
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Cheng W, Ndoka E, Maung JN, Pan W, Rupp AC, Rhodes CJ, Olson DP, Myers MG. NTS Prlh overcomes orexigenic stimuli and ameliorates dietary and genetic forms of obesity. Nat Commun 2021; 12:5175. [PMID: 34462445 PMCID: PMC8405610 DOI: 10.1038/s41467-021-25525-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 08/11/2021] [Indexed: 11/09/2022] Open
Abstract
Calcitonin receptor (Calcr)-expressing neurons of the nucleus tractus solitarius (NTS; CalcrNTS cells) contribute to the long-term control of food intake and body weight. Here, we show that Prlh-expressing NTS (PrlhNTS) neurons represent a subset of CalcrNTS cells and that Prlh expression in these cells restrains body weight gain in the face of high fat diet challenge in mice. To understand the relationship of PrlhNTS cells to hypothalamic feeding circuits, we determined the ability of PrlhNTS-mediated signals to overcome enforced activation of AgRP neurons. We found that PrlhNTS neuron activation and Prlh overexpression in PrlhNTS cells abrogates AgRP neuron-driven hyperphagia and ameliorates the obesity of mice deficient in melanocortin signaling or leptin. Thus, enhancing Prlh-mediated neurotransmission from the NTS dampens hypothalamically-driven hyperphagia and obesity, demonstrating that NTS-mediated signals can override the effects of orexigenic hypothalamic signals on long-term energy balance. Calcitonin receptor-expressing neurons of the nucleus tractus solitarius contribute to long-term control of food intake and body weight. The authors show that a subset of these cells expresses Prlh and that enhancing Prlh-mediated neurotransmission from the NTS dampens hypothalamically-driven hyperphagia and obesity in mice.
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Affiliation(s)
- Wenwen Cheng
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA.
| | - Ermelinda Ndoka
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Jessica N Maung
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Warren Pan
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Alan C Rupp
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Christopher J Rhodes
- Research and Early Development, Cardiovascular, Renal, and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA
| | - David P Olson
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA.,Division of Endocrinology, Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA
| | - Martin G Myers
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA. .,Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA.
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7
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Affinati AH, Sabatini PV, True C, Tomlinson AJ, Kirigiti M, Lindsley SR, Li C, Olson DP, Kievit P, Myers MG, Rupp AC. Cross-species analysis defines the conservation of anatomically segregated VMH neuron populations. eLife 2021; 10:69065. [PMID: 34018926 PMCID: PMC8184210 DOI: 10.7554/elife.69065] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 05/14/2021] [Indexed: 12/14/2022] Open
Abstract
The ventromedial hypothalamic nucleus (VMH) controls diverse behaviors and physiologic functions, suggesting the existence of multiple VMH neural subtypes with distinct functions. Combing translating ribosome affinity purification with RNA-sequencing (TRAP-seq) data with single-nucleus RNA-sequencing (snRNA-seq) data, we identified 24 mouse VMH neuron clusters. Further analysis, including snRNA-seq data from macaque tissue, defined a more tractable VMH parceling scheme consisting of six major genetically and anatomically differentiated VMH neuron classes with good cross-species conservation. In addition to two major ventrolateral classes, we identified three distinct classes of dorsomedial VMH neurons. Consistent with previously suggested unique roles for leptin receptor (Lepr)-expressing VMH neurons, Lepr expression marked a single dorsomedial class. We also identified a class of glutamatergic VMH neurons that resides in the tuberal region, anterolateral to the neuroanatomical core of the VMH. This atlas of conserved VMH neuron populations provides an unbiased starting point for the analysis of VMH circuitry and function.
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Affiliation(s)
- Alison H Affinati
- Department of Internal Medicine, University of Michigan, Ann Arbor, United States
| | - Paul V Sabatini
- Department of Internal Medicine, University of Michigan, Ann Arbor, United States
| | - Cadence True
- Oregon National Primate Research Center, Beaverton, United States
| | - Abigail J Tomlinson
- Department of Internal Medicine, University of Michigan, Ann Arbor, United States
| | - Melissa Kirigiti
- Oregon National Primate Research Center, Beaverton, United States
| | - Sarah R Lindsley
- Oregon National Primate Research Center, Beaverton, United States
| | - Chien Li
- Novo Nordisk Research Center, Seattle, United States
| | - David P Olson
- Department of Pediatrics, University of Michigan, Ann Arbor, United States
| | - Paul Kievit
- Oregon National Primate Research Center, Beaverton, United States
| | - Martin G Myers
- Department of Internal Medicine, University of Michigan, Ann Arbor, United States
| | - Alan C Rupp
- Department of Internal Medicine, University of Michigan, Ann Arbor, United States
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8
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Sabatini PV, Wang J, Rupp AC, Affinati AH, Flak JN, Li C, Olson DP, Myers MG. tTARGIT AAVs mediate the sensitive and flexible manipulation of intersectional neuronal populations in mice. eLife 2021; 10:66835. [PMID: 33704065 PMCID: PMC8026215 DOI: 10.7554/elife.66835] [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] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Accepted: 03/10/2021] [Indexed: 12/20/2022] Open
Abstract
While Cre-dependent viral systems permit the manipulation of many neuron types, some cell populations cannot be targeted by a single DNA recombinase. Although the combined use of Flp and Cre recombinases can overcome this limitation, insufficient recombinase activity can reduce the efficacy of existing Cre+Flp-dependent viral systems. We developed a sensitive dual recombinase-activated viral approach: tTA-driven Recombinase-Guided Intersectional Targeting (tTARGIT) adeno-associated viruses (AAVs). tTARGIT AAVs utilize a Flp-dependent tetracycline transactivator (tTA) ‘Driver’ AAV and a tetracycline response element-driven, Cre-dependent ‘Payload’ AAV to express the transgene of interest. We employed this system in Slc17a6FlpO;LeprCre mice to manipulate LepRb neurons of the ventromedial hypothalamus (VMH; LepRbVMH neurons) while omitting neighboring LepRb populations. We defined the circuitry of LepRbVMH neurons and roles for these cells in the control of food intake and energy expenditure. Thus, the tTARGIT system mediates robust recombinase-sensitive transgene expression, permitting the precise manipulation of previously intractable neural populations. The brain contains hundreds of types of neurons, which differ in size, shape and behavior. But neuroscientists often wish to study individual neuronal types in isolation. They are able to do this with the aid of a toolkit made up of two parts: viral vectors and genetically modified mice. Viral vectors are viruses that have been modified so that they are no longer harmful and can instead be used to introduce genetic material into cells on demand. To create a viral vector, the virus’ own genetic material is replaced with a ‘cargo’ gene, such as the gene for a fluorescent protein. The virus is then introduced into a new host such as a mouse. Importantly, the virus only produces the protein encoded by its ‘cargo’ gene if it is inside a cell that also contains one of two specific enzymes. These enzymes are called Cre and Flp. This is where the second part of the toolkit comes in. Mice can be genetically engineered to produce either Cre or Flp exclusively in specific cell types. By introducing a viral vector into mice that produce either Cre or Flp only in one particular type of neuron, researchers can limit the activity of the cargo gene to that neuronal type. But sometimes even this approach is not selective enough. Researchers may wish to limit the activity of the cargo gene to a subpopulation of cells that produce Cre or Flp. Or they may wish to target only Cre- or Flp-producing cells in a small area of the brain, while leaving cells in neighboring areas unaffected. Sabatini et al. have now overcome this limitation by developing and testing a new set of viral vectors that are active only in neurons that produce both Cre and Flp. The vectors are called tTARGIT AAVs and allow researchers to target cells more precisely than was possible with the previous version of the toolkit. Sabatini et al. show tTARGIT AAVs in action by using them to identify a group of neurons that control how much energy mice use and how much food they eat. As well as applying the vectors to their own research on obesity, Sabatini et al. have also made them freely available for other researchers to use in their own projects.
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Affiliation(s)
- Paul V Sabatini
- Department of Internal Medicine, University of Michigan, Ann Arbor, United States
| | - Jine Wang
- Department of Internal Medicine, University of Michigan, Ann Arbor, United States.,Chinese academy, College of Medical Science, China Three Gorges University, Yichang, China
| | - Alan C Rupp
- Department of Internal Medicine, University of Michigan, Ann Arbor, United States
| | - Alison H Affinati
- Department of Internal Medicine, University of Michigan, Ann Arbor, United States
| | - Jonathan N Flak
- Indiana Biosciences Research Institute, Indianapolis, United States
| | - Chien Li
- Novo Nordisk Research Center, Seattle, United States
| | - David P Olson
- Department of Pediatrics, University of Michigan, Ann Arbor, United States.,Department of Molecular and Integrative Physiology, Ann Arbor, United States
| | - Martin G Myers
- Department of Internal Medicine, University of Michigan, Ann Arbor, United States.,Department of Molecular and Integrative Physiology, Ann Arbor, United States
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9
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Sabatini PV, Frikke-Schmidt H, Arthurs J, Gordian D, Patel A, Rupp AC, Adams JM, Wang J, Beck Jørgensen S, Olson DP, Palmiter RD, Myers MG, Seeley RJ. GFRAL-expressing neurons suppress food intake via aversive pathways. Proc Natl Acad Sci U S A 2021; 118:e2021357118. [PMID: 33593916 PMCID: PMC7923658 DOI: 10.1073/pnas.2021357118] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [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] [Indexed: 12/17/2022] Open
Abstract
The TGFβ cytokine family member, GDF-15, reduces food intake and body weight and represents a potential treatment for obesity. Because the brainstem-restricted expression pattern of its receptor, GDNF Family Receptor α-like (GFRAL), presents an exciting opportunity to understand mechanisms of action for area postrema neurons in food intake; we generated GfralCre and conditional GfralCreERT mice to visualize and manipulate GFRAL neurons. We found infection or pathophysiologic states (rather than meal ingestion) stimulate GFRAL neurons. TRAP-Seq analysis of GFRAL neurons revealed their expression of a wide range of neurotransmitters and neuropeptides. Artificially activating GfralCre -expressing neurons inhibited feeding, decreased gastric emptying, and promoted a conditioned taste aversion (CTA). GFRAL neurons most strongly innervate the parabrachial nucleus (PBN), where they target CGRP-expressing (CGRPPBN) neurons. Silencing CGRPPBN neurons abrogated the aversive and anorexic effects of GDF-15. These findings suggest that GFRAL neurons link non-meal-associated pathophysiologic signals to suppress nutrient uptake and absorption.
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Affiliation(s)
- Paul V Sabatini
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109
| | | | - Joe Arthurs
- Howard Hughes Medical Institute and Department of Biochemistry, University of Washington, Seattle, WA 98115
- Howard Hughes Medical Institute and Department of Genome Sciences, University of Washington, Seattle, WA 98115
| | - Desiree Gordian
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109
| | - Anita Patel
- Department of Surgery, University of Michigan, Ann Arbor, MI 48109
| | - Alan C Rupp
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109
| | - Jessica M Adams
- Department of Pediatrics, University of Michigan, Ann Arbor, MI 48109
- School of Biological Sciences, Illinois State University, Normal, IL 61790
| | - Jine Wang
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109
- College of Medical Science, China Three Gorges University, 43002 Yichang, China
| | | | - David P Olson
- Department of Pediatrics, University of Michigan, Ann Arbor, MI 48109
| | - Richard D Palmiter
- Howard Hughes Medical Institute and Department of Biochemistry, University of Washington, Seattle, WA 98115
- Howard Hughes Medical Institute and Department of Genome Sciences, University of Washington, Seattle, WA 98115
| | - Martin G Myers
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109
| | - Randy J Seeley
- Department of Surgery, University of Michigan, Ann Arbor, MI 48109;
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10
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Cote JL, Argetsinger LS, Flores A, Rupp AC, Cline JM, DeSantis LC, Bedard AH, Bagchi DP, Vander PB, Cacciaglia AM, Clutter ES, Chandrashekar G, MacDougald OA, Myers MG, Carter-Su C. Deletion of the Brain-Specific α and δ Isoforms of Adapter Protein SH2B1 Protects Mice From Obesity. Diabetes 2021; 70:400-414. [PMID: 33214137 PMCID: PMC7881872 DOI: 10.2337/db20-0687] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 11/12/2020] [Indexed: 11/13/2022]
Abstract
Mice lacking SH2B1 and humans with variants of SH2B1 display severe obesity and insulin resistance. SH2B1 is an adapter protein that is recruited to the receptors of multiple hormones and neurotrophic factors. Of the four known alternatively spliced SH2B1 isoforms, SH2B1β and SH2B1γ exhibit ubiquitous expression, whereas SH2B1α and SH2B1δ are essentially restricted to the brain. To understand the roles for SH2B1α and SH2B1δ in energy balance and glucose metabolism, we generated mice lacking these brain-specific isoforms (αδ knockout [αδKO] mice). αδKO mice exhibit decreased food intake, protection from weight gain on standard and high-fat diets, and an adiposity-dependent improvement in glucose homeostasis. SH2B1 has been suggested to impact energy balance via the modulation of leptin action. However, αδKO mice exhibit leptin sensitivity that is similar to that of wild-type mice by multiple measures. Thus, decreasing the abundance of SH2B1α and/or SH2B1δ relative to the other SH2B1 isoforms likely shifts energy balance toward a lean phenotype via a primarily leptin-independent mechanism. Our findings suggest that the different alternatively spliced isoforms of SH2B1 perform different functions in vivo.
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Affiliation(s)
- Jessica L Cote
- Neuroscience Program, University of Michigan Medical School, Ann Arbor, MI
| | - Lawrence S Argetsinger
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
| | - Anabel Flores
- Cell and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI
| | - Alan C Rupp
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI
| | - Joel M Cline
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
| | - Lauren C DeSantis
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
| | - Alexander H Bedard
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
| | - Devika P Bagchi
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
| | - Paul B Vander
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
| | - Abrielle M Cacciaglia
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
| | - Erik S Clutter
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
| | - Gowri Chandrashekar
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
| | - Ormond A MacDougald
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
- Cell and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI
| | - Martin G Myers
- Neuroscience Program, University of Michigan Medical School, Ann Arbor, MI
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
- Cell and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI
| | - Christin Carter-Su
- Neuroscience Program, University of Michigan Medical School, Ann Arbor, MI
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
- Cell and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI
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11
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Rupp AC, Ren M, Altimus CM, Fernandez DC, Richardson M, Turek F, Hattar S, Schmidt TM. Distinct ipRGC subpopulations mediate light's acute and circadian effects on body temperature and sleep. eLife 2019; 8:44358. [PMID: 31333190 PMCID: PMC6650245 DOI: 10.7554/elife.44358] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 06/18/2019] [Indexed: 12/16/2022] Open
Abstract
The light environment greatly impacts human alertness, mood, and cognition by both acute regulation of physiology and indirect alignment of circadian rhythms. These processes require the melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs), but the relevant downstream brain areas involved remain elusive. ipRGCs project widely in the brain, including to the central circadian pacemaker, the suprachiasmatic nucleus (SCN). Here we show that body temperature and sleep responses to acute light exposure are absent after genetic ablation of all ipRGCs except a subpopulation that projects to the SCN. Furthermore, by chemogenetic activation of the ipRGCs that avoid the SCN, we show that these cells are sufficient for acute changes in body temperature. Our results challenge the idea that the SCN is a major relay for the acute effects of light on non-image forming behaviors and identify the sensory cells that initiate light’s profound effects on body temperature and sleep. Light, whether natural or artificial, affects our everyday lives in several ways. Exposure to light impacts on our health and well-being. It plays a crucial but indirect role in helping to align our internal body clock with the 24-hour cycle of day and night, and a burst of bright light in the middle of the night can wake us up from sleep. Decades of research have revealed the circuitry that controls the indirect effects of light on the body's internal clock. A tiny set of cells in the base of the brain called the suprachiasmatic nucleus (SCN for short) generates the body’s daily or “circadian” rhythm. A small group of nerve cells in the retina of the eye called intrinsically photosensitive retinal ganglion cells (ipRGCs) connect with the SCN. These ipRGCs relay information about light to the SCN to ensure that daily rhythms happen at the appropriate times of day. But scientists do not yet know if the same brain circuits regulate the direct effects of light on alertness. Mice are often used in studies of circadian rhythms but, unlike humans, mice are normally active at night and sleep throughout the day. This means that a burst of bright light in the middle of the night causes mice to become less alert. Now, in experiments with mice, Rupp et al. show there are two separate circuits from the retina to the brain that influence wakefulness. In the experiments, some mice were genetically engineered to only have ipRGCs that connect with the SCN and to lack those that connect with other brain areas. These mice lived in cages with a normal day/night cycle and their body temperature and sleep-related brain activity were monitored as Rupp et al. sporadically exposed them to bright light at night. These mice continued their normal routines and were unaffected by the bursts of light. In a second set of experiments, ipRGCs that do not connect with the SCN were activated in other mice. This caused an immediate and sustained drop in the body temperature of the mice, which is linked to them becoming less alert. The experiments suggest that the circuit that connects ipRGCs to the SCN to align the body’s circadian rhythm with light does not control the direct effect of light on wakefulness. Instead, a separate circuit that extends from ipRGCs to an unknown part of the brain area influences wakefulness. Better understanding this second circuit could allow scientists to develop ways to keep people like emergency personnel or overnight shift workers awake and alert at night while avoiding harmful disruptions to their circadian rhythms.
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Affiliation(s)
- Alan C Rupp
- Department of Biology, Johns Hopkins University, Baltimore, United States
| | - Michelle Ren
- Department of Neurobiology, Northwestern University, Evanston, United States
| | - Cara M Altimus
- Department of Biology, Johns Hopkins University, Baltimore, United States
| | - Diego C Fernandez
- Department of Biology, Johns Hopkins University, Baltimore, United States
| | - Melissa Richardson
- Department of Biology, Johns Hopkins University, Baltimore, United States
| | - Fred Turek
- Department of Neurobiology, Northwestern University, Evanston, United States
| | - Samer Hattar
- Department of Biology, Johns Hopkins University, Baltimore, United States.,Department of Neuroscience, Johns Hopkins University, Baltimore, United States
| | - Tiffany M Schmidt
- Department of Neurobiology, Northwestern University, Evanston, United States
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12
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Rupp AC, Allison MB, Jones JC, Patterson CM, Faber CL, Bozadjieva N, Heisler LK, Seeley RJ, Olson DP, Myers MG. Specific subpopulations of hypothalamic leptin receptor-expressing neurons mediate the effects of early developmental leptin receptor deletion on energy balance. Mol Metab 2018; 14:130-138. [PMID: 29914853 PMCID: PMC6034096 DOI: 10.1016/j.molmet.2018.06.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [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: 04/26/2018] [Revised: 05/25/2018] [Accepted: 06/02/2018] [Indexed: 01/29/2023] Open
Abstract
OBJECTIVE To date, early developmental ablation of leptin receptor (LepRb) expression from circumscribed populations of hypothalamic neurons (e.g., arcuate nucleus (ARC) Pomc- or Agrp-expressing cells) has only minimally affected energy balance. In contrast, removal of LepRb from at least two large populations (expressing vGat or Nos1) spanning multiple hypothalamic regions produced profound obesity and metabolic dysfunction. Thus, we tested the notion that the total number of leptin-responsive hypothalamic neurons (rather than specific subsets of cells with a particular molecular or anatomical signature) subjected to early LepRb deletion might determine energy balance. METHODS We generated new mouse lines deleted for LepRb in ARC GhrhCre neurons or in Htr2cCre neurons (representing roughly half of all hypothalamic LepRb neurons, distributed across many nuclei). We compared the phenotypes of these mice to previously-reported models lacking LepRb in Pomc, Agrp, vGat or Nos1 cells. RESULTS The early developmental deletion of LepRb from vGat or Nos1 neurons produced dramatic obesity, but deletion of LepRb from Pomc, Agrp, Ghrh, or Htr2c neurons minimally altered energy balance. CONCLUSIONS Although early developmental deletion of LepRb from known populations of ARC neurons fails to substantially alter body weight, the minimal phenotype of mice lacking LepRb in Htr2c cells suggests that the phenotype that results from early developmental LepRb deficiency depends not simply upon the total number of leptin-responsive hypothalamic LepRb cells. Rather, specific populations of LepRb neurons must play particularly important roles in body energy homeostasis; these as yet unidentified LepRb cells likely reside in the DMH.
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Affiliation(s)
- Alan C Rupp
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Margaret B Allison
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Justin C Jones
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Christa M Patterson
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Chelsea L Faber
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Nadejda Bozadjieva
- Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | | | - Randy J Seeley
- Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - David P Olson
- Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Martin G Myers
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA.
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13
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Keenan WT, Rupp AC, Ross RA, Somasundaram P, Hiriyanna S, Wu Z, Badea TC, Robinson PR, Lowell BB, Hattar SS. A visual circuit uses complementary mechanisms to support transient and sustained pupil constriction. eLife 2016; 5:e15392. [PMID: 27669145 PMCID: PMC5079752 DOI: 10.7554/elife.15392] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [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: 02/19/2016] [Accepted: 09/22/2016] [Indexed: 12/22/2022] Open
Abstract
Rapid and stable control of pupil size in response to light is critical for vision, but the neural coding mechanisms remain unclear. Here, we investigated the neural basis of pupil control by monitoring pupil size across time while manipulating each photoreceptor input or neurotransmitter output of intrinsically photosensitive retinal ganglion cells (ipRGCs), a critical relay in the control of pupil size. We show that transient and sustained pupil responses are mediated by distinct photoreceptors and neurotransmitters. Transient responses utilize input from rod photoreceptors and output by the classical neurotransmitter glutamate, but adapt within minutes. In contrast, sustained responses are dominated by non-conventional signaling mechanisms: melanopsin phototransduction in ipRGCs and output by the neuropeptide PACAP, which provide stable pupil maintenance across the day. These results highlight a temporal switch in the coding mechanisms of a neural circuit to support proper behavioral dynamics.
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Affiliation(s)
| | - Alan C Rupp
- Department of Biology, Johns Hopkins University, Baltimore, United States
| | - Rachel A Ross
- Department of Psychiatry, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, United States
- Department of Psychiatry, Massachusetts General Hospital, Boston, United States
| | - Preethi Somasundaram
- Department of Biological Sciences, University of Marlyand, Baltimore, United States
| | - Suja Hiriyanna
- National Eye Institute, National Institutes of Health, Bethesda, United States
| | - Zhijian Wu
- National Eye Institute, National Institutes of Health, Bethesda, United States
| | - Tudor C Badea
- National Eye Institute, National Institutes of Health, Bethesda, United States
| | - Phyllis R Robinson
- Department of Biological Sciences, University of Marlyand, Baltimore, United States
| | - Bradford B Lowell
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, United States
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, United States
- Program in Neuroscience, Harvard Medical School, Boston, United States
| | - Samer S Hattar
- Department of Biology, Johns Hopkins University, Baltimore, United States
- Department of Neuroscience, Johns Hopkins University, Baltimore, United States
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14
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Xue Y, Shen SQ, Jui J, Rupp AC, Byrne LC, Hattar S, Flannery JG, Corbo JC, Kefalov VJ. CRALBP supports the mammalian retinal visual cycle and cone vision. J Clin Invest 2015; 125:727-38. [PMID: 25607845 DOI: 10.1172/jci79651] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 12/11/2014] [Indexed: 11/17/2022] Open
Abstract
Mutations in the cellular retinaldehyde-binding protein (CRALBP, encoded by RLBP1) can lead to severe cone photoreceptor-mediated vision loss in patients. It is not known how CRALBP supports cone function or how altered CRALBP leads to cone dysfunction. Here, we determined that deletion of Rlbp1 in mice impairs the retinal visual cycle. Mice lacking CRALBP exhibited M-opsin mislocalization, M-cone loss, and impaired cone-driven visual behavior and light responses. Additionally, M-cone dark adaptation was largely suppressed in CRALBP-deficient animals. While rearing CRALBP-deficient mice in the dark prevented the deterioration of cone function, it did not rescue cone dark adaptation. Adeno-associated virus-mediated restoration of CRALBP expression specifically in Müller cells, but not retinal pigment epithelial (RPE) cells, rescued the retinal visual cycle and M-cone sensitivity in knockout mice. Our results identify Müller cell CRALBP as a key component of the retinal visual cycle and demonstrate that this pathway is important for maintaining normal cone-driven vision and accelerating cone dark adaptation.
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15
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Chew KS, Schmidt TM, Rupp AC, Kofuji P, Trimarchi JM. Loss of gq/11 genes does not abolish melanopsin phototransduction. PLoS One 2014; 9:e98356. [PMID: 24870805 PMCID: PMC4037210 DOI: 10.1371/journal.pone.0098356] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 05/01/2014] [Indexed: 11/29/2022] Open
Abstract
In mammals, a subset of retinal ganglion cells (RGCs) expresses the photopigment melanopsin, which renders them intrinsically photosensitive (ipRGCs). These ipRGCs mediate various non-image-forming visual functions such as circadian photoentrainment and the pupillary light reflex (PLR). Melanopsin phototransduction begins with activation of a heterotrimeric G protein of unknown identity. Several studies of melanopsin phototransduction have implicated a G-protein of the Gq/11 family, which consists of Gna11, Gna14, Gnaq and Gna15, in melanopsin-evoked depolarization. However, the exact identity of the Gq/11 gene involved in this process has remained elusive. Additionally, whether Gq/11 G-proteins are necessary for melanopsin phototransduction in vivo has not yet been examined. We show here that the majority of ipRGCs express both Gna11 and Gna14, but neither Gnaq nor Gna15. Animals lacking the melanopsin protein have well-characterized deficits in the PLR and circadian behaviors, and we therefore examined these non-imaging forming visual functions in a variety of single and double mutants for Gq/11 family members. All Gq/11 mutant animals exhibited PLR and circadian behaviors indistinguishable from WT. In addition, we show persistence of ipRGC light-evoked responses in Gna11−/−; Gna14−/− retinas using multielectrode array recordings. These results demonstrate that Gq, G11, G14, or G15 alone or in combination are not necessary for melanopsin-based phototransduction, and suggest that ipRGCs may be able to utilize a Gq/11-independent phototransduction cascade in vivo.
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Affiliation(s)
- Kylie S. Chew
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, United States of America
- * E-mail:
| | - Tiffany M. Schmidt
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Alan C. Rupp
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Paulo Kofuji
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Jeffrey M. Trimarchi
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, United States of America
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16
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Bedont JL, LeGates TA, Slat EA, Byerly MS, Wang H, Hu J, Rupp AC, Qian J, Wong GW, Herzog ED, Hattar S, Blackshaw S. Lhx1 controls terminal differentiation and circadian function of the suprachiasmatic nucleus. Cell Rep 2014; 7:609-22. [PMID: 24767996 PMCID: PMC4254772 DOI: 10.1016/j.celrep.2014.03.060] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 02/23/2014] [Accepted: 03/21/2014] [Indexed: 12/27/2022] Open
Abstract
Vertebrate circadian rhythms are organized by the hypothalamic suprachiasmatic nucleus (SCN). Despite its physiological importance, SCN development is poorly understood. Here, we show that Lim homeodomain transcription factor 1 (Lhx1) is essential for terminal differentiation and function of the SCN. Deletion of Lhx1 in the developing SCN results in loss of SCN-enriched neuropeptides involved in synchronization and coupling to downstream oscillators, among other aspects of circadian function. Intact, albeit damped, clock gene expression rhythms persist in Lhx1-deficient SCN; however, circadian activity rhythms are highly disorganized and susceptible to surprising changes in period, phase, and consolidation following neuropeptide infusion. Our results identify a factor required for SCN terminal differentiation. In addition, our in vivo study of combinatorial SCN neuropeptide disruption uncovered synergies among SCN-enriched neuropeptides in regulating normal circadian function. These animals provide a platform for studying the central oscillator's role in physiology and cognition.
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Affiliation(s)
- Joseph L Bedont
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Tara A LeGates
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Emily A Slat
- Department of Biology, Washington University, St. Louis, MO 63130, USA
| | - Mardi S Byerly
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Hong Wang
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Jianfei Hu
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Alan C Rupp
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Jiang Qian
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - G William Wong
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Erik D Herzog
- Department of Biology, Washington University, St. Louis, MO 63130, USA
| | - Samer Hattar
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Seth Blackshaw
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Center for High-Throughput Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
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