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Abu-Rub LI, Al-Barazenji T, Abiib S, Hammad AS, Abbas A, Hussain K, Al-Shafai M. Identification of KSR2 Variants in Pediatric Patients with Severe Early-Onset Obesity from Qatar. Genes (Basel) 2024; 15:966. [PMID: 39202327 DOI: 10.3390/genes15080966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2024] [Revised: 07/14/2024] [Accepted: 07/18/2024] [Indexed: 09/03/2024] Open
Abstract
The kinase suppressor of Ras 2 (KSR2) gene is associated with monogenic obesity, and loss-of-function variants in KSR2 have been identified in individuals with severe early-onset obesity. This study investigated KSR2 variants in 9 pediatric patients with severe early-onset obesity in Qatar using whole genome sequencing among a cohort of 240 individuals. We focused on KSR2 variants with a minor allele frequency (MAF) below 1% and a Combined Annotation Dependent Depletion (CADD) score above 13 to identify potential causative variants. Our analysis identified four KSR2 variants: one intronic (c.1765-8G>A) and three missense variants (c.1057G>A, c.1673G>A, and c.923T>C) in nine patients. The intronic variant c.1765-8G>A was the most frequent (seen in six individuals) and had a CADD score of 21.10, suggesting possible pathogenicity. This variant showed a significantly higher allele frequency in the Qatari population compared to the Genome Aggregation Database (gnomAD), indicating a possible founder effect. Molecular modeling of the missense variants revealed structural changes in the protein structure. The study concludes that these four KSR2 variants are associated with monogenic obesity, with an autosomal dominant inheritance pattern. The c.1765-8G>A variant's prevalence in Qatar underscores its importance in genetic screening for severe obesity. This research advances the understanding of genetic factors in severe early-onset obesity and may inform better management strategies.
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Affiliation(s)
- Lubna I Abu-Rub
- Department of Biomedical Sciences, College of Health Sciences, QU Health, Qatar University, Doha 2713, Qatar
| | - Tara Al-Barazenji
- Department of Biomedical Sciences, College of Health Sciences, QU Health, Qatar University, Doha 2713, Qatar
| | - Sumaya Abiib
- Department of Biomedical Sciences, College of Health Sciences, QU Health, Qatar University, Doha 2713, Qatar
| | - Ayat S Hammad
- Department of Biomedical Sciences, College of Health Sciences, QU Health, Qatar University, Doha 2713, Qatar
| | - Alaa Abbas
- Department of Biomedical Sciences, College of Health Sciences, QU Health, Qatar University, Doha 2713, Qatar
| | - Khalid Hussain
- Division of Endocrinology, Department of Pediatric Medicine, Sidra Medicine, Doha P.O. Box 26999, Qatar
| | - Mashael Al-Shafai
- Department of Biomedical Sciences, College of Health Sciences, QU Health, Qatar University, Doha 2713, Qatar
- Biomedical Research Center, Qatar University, Doha P.O. Box 2713, Qatar
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2
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Gomez GA, Rundle CH, Xing W, Kesavan C, Pourteymoor S, Lewis RE, Powell DR, Mohan S. Contrasting effects of <i>Ksr2</i>, an obesity gene, on trabecular bone volume and bone marrow adiposity. eLife 2022; 11:82810. [PMID: 36342465 PMCID: PMC9640193 DOI: 10.7554/elife.82810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 10/06/2022] [Indexed: 11/25/2022] Open
Abstract
Pathological obesity and its complications are associated with an increased propensity for bone fractures. Humans with certain genetic polymorphisms at the kinase suppressor of ras2 (KSR2) locus develop severe early-onset obesity and type 2 diabetes. Both conditions are phenocopied in mice with <i>Ksr2</i> deleted, but whether this affects bone health remains unknown. Here we studied the bones of global <i>Ksr2</i> null mice and found that <i>Ksr2</i> negatively regulates femoral, but not vertebral, bone mass in two genetic backgrounds, while the paralogous gene, <i>Ksr1</i>, was dispensable for bone homeostasis. Mechanistically, KSR2 regulates bone formation by influencing adipocyte differentiation at the expense of osteoblasts in the bone marrow. Compared with <i>Ksr2</i>'s known role as a regulator of feeding by its function in the hypothalamus, pair-feeding and osteoblast-specific conditional deletion of <i>Ksr2</i> reveals that <i>Ksr2</i> can regulate bone formation autonomously. Despite the gains in appendicular bone mass observed in the absence of <i>Ksr2</i>, bone strength, as well as fracture healing response, remains compromised in these mice. This study highlights the interrelationship between adiposity and bone health and provides mechanistic insights into how <i>Ksr2</i>, an adiposity and diabetic gene, regulates bone metabolism.
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Affiliation(s)
| | - Charles H Rundle
- VA Loma Linda Healthcare SystemLoma LindaUnited States,Loma Linda University Medical CenterLoma LindaUnited States
| | - Weirong Xing
- VA Loma Linda Healthcare SystemLoma LindaUnited States,Loma Linda University Medical CenterLoma LindaUnited States
| | - Chandrasekhar Kesavan
- VA Loma Linda Healthcare SystemLoma LindaUnited States,Loma Linda University Medical CenterLoma LindaUnited States
| | | | | | | | - Subburaman Mohan
- VA Loma Linda Healthcare SystemLoma LindaUnited States,Loma Linda University Medical CenterLoma LindaUnited States
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3
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Dasgupta A, Shukla SK, Vernucci E, King RJ, Abrego J, Mulder SE, Mullen NJ, Graves G, Buettner K, Thakur R, Murthy D, Attri KS, Wang D, Chaika NV, Pacheco CG, Rai I, Engle DD, Grandgenett PM, Punsoni M, Reames BN, Teoh-Fitzgerald M, Oberley-Deegan R, Yu F, Klute KA, Hollingsworth MA, Zimmerman MC, Mehla K, Sadoshima J, Tuveson DA, Singh PK. SIRT1-NOX4 signaling axis regulates cancer cachexia. J Exp Med 2021; 217:151806. [PMID: 32441762 PMCID: PMC7336299 DOI: 10.1084/jem.20190745] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 01/31/2020] [Accepted: 04/08/2020] [Indexed: 12/21/2022] Open
Abstract
Approximately one third of cancer patients die due to complexities related to cachexia. However, the mechanisms of cachexia and the potential therapeutic interventions remain poorly studied. We observed a significant positive correlation between SIRT1 expression and muscle fiber cross-sectional area in pancreatic cancer patients. Rescuing Sirt1 expression by exogenous expression or pharmacological agents reverted cancer cell–induced myotube wasting in culture conditions and mouse models. RNA-seq and follow-up analyses showed cancer cell–mediated SIRT1 loss induced NF-κB signaling in cachectic muscles that enhanced the expression of FOXO transcription factors and NADPH oxidase 4 (Nox4), a key regulator of reactive oxygen species production. Additionally, we observed a negative correlation between NOX4 expression and skeletal muscle fiber cross-sectional area in pancreatic cancer patients. Knocking out Nox4 in skeletal muscles or pharmacological blockade of Nox4 activity abrogated tumor-induced cachexia in mice. Thus, we conclude that targeting the Sirt1–Nox4 axis in muscles is an effective therapeutic intervention for mitigating pancreatic cancer–induced cachexia.
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Affiliation(s)
- Aneesha Dasgupta
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE
| | - Surendra K Shukla
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE
| | - Enza Vernucci
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE
| | - Ryan J King
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE
| | - Jaime Abrego
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE
| | - Scott E Mulder
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE
| | - Nicholas J Mullen
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE
| | - Gavin Graves
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE
| | - Kyla Buettner
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE
| | - Ravi Thakur
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE
| | - Divya Murthy
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE
| | - Kuldeep S Attri
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE
| | - Dezhen Wang
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE
| | - Nina V Chaika
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE
| | - Camila G Pacheco
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE
| | - Ibha Rai
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE
| | - Dannielle D Engle
- Cancer Center at Cold Spring Harbor Laboratory, Cold Spring Harbor, NY
| | - Paul M Grandgenett
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE
| | - Michael Punsoni
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE
| | - Bradley N Reames
- Department of Surgery, University of Nebraska Medical Center, Omaha, NE
| | - Melissa Teoh-Fitzgerald
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE
| | - Rebecca Oberley-Deegan
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE
| | - Fang Yu
- Department of Biostatistics, University of Nebraska Medical Center, Omaha, NE
| | - Kelsey A Klute
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE
| | - Michael A Hollingsworth
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE
| | - Matthew C Zimmerman
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE
| | - Kamiya Mehla
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE
| | - Junichi Sadoshima
- Department of Cell Biology and Molecular Medicine, New Jersey Medical School, Rutgers University, Newark, NJ
| | - David A Tuveson
- Cancer Center at Cold Spring Harbor Laboratory, Cold Spring Harbor, NY
| | - Pankaj K Singh
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE.,The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE.,Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE
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4
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King SE, Nilsson E, Beck D, Skinner MK. Adipocyte epigenetic alterations and potential therapeutic targets in transgenerationally inherited lean and obese phenotypes following ancestral exposures. Adipocyte 2019; 8:362-378. [PMID: 31755359 PMCID: PMC6948971 DOI: 10.1080/21623945.2019.1693747] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 10/30/2019] [Accepted: 11/11/2019] [Indexed: 01/01/2023] Open
Abstract
The incidence of obesity has increased dramatically over the past two decades with a prevalence of approximately 40% of the adult population within the United States. The current study examines the potential for transgenerational adipocyte (fat cell) epigenetic alterations. Adipocytes were isolated from the gonadal fat pad of the great-grand offspring F3 generation 1-year old rats ancestrally exposed to DDT (dichlorodiphenyltrichloroethane), atrazine, or vehicle control in order to obtain adipocytes for DNA methylation analysis. Observations indicate that there were differential DNA methylated regions (DMRs) in the adipocytes with the lean or obese phenotypes compared to control normal (non-obese or lean) populations. The comparison of epigenetic alterations indicated that there were substantial overlaps between the different treatment lineage groups for both the lean and obese phenotypes. Novel correlated genes and gene pathways associated with DNA methylation were identified, and may aid in the discovery of potential therapeutic targets for metabolic diseases such as obesity. Observations indicate that ancestral exposures during critical windows of development can induce the epigenetic transgenerational inheritance of DNA methylation changes in adipocytes that ultimately may contribute to an altered metabolic phenotype.
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Affiliation(s)
- Stephanie E. King
- Center for Reproductive Biology, School of Biological Sciences, Washington State University, Pullman, WA, USA
| | - Eric Nilsson
- Center for Reproductive Biology, School of Biological Sciences, Washington State University, Pullman, WA, USA
| | - Daniel Beck
- Center for Reproductive Biology, School of Biological Sciences, Washington State University, Pullman, WA, USA
| | - Michael K. Skinner
- Center for Reproductive Biology, School of Biological Sciences, Washington State University, Pullman, WA, USA
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5
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Moretti E, Collodel G, Belmonte G, Noto D, Giurisato E. Defective spermatogenesis and testosterone levels in kinase suppressor of Ras1 (KSR1)-deficient mice. Reprod Fertil Dev 2019; 31:1369-1377. [PMID: 30981290 DOI: 10.1071/rd18386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 02/08/2019] [Indexed: 11/23/2022] Open
Abstract
The aim of this study was to clarify the role of the protein kinase suppressor of Ras1 (KSR1) in spermatogenesis. Spermatogenesis in ksr1 -/- mice was studied in testicular tissue and epididymal spermatozoa by light and transmission electron microscopy and by immunofluorescence using antibodies to ghrelin and 3β-hydroxysteroid dehydrogenase (3β-HSD). Blood testosterone levels were also assessed. ksr1 -/- mice showed reduced epididymal sperm concentration and motility as compared with wild- type (wt) mice. Testis tissue from ksr1 -/- mice revealed a prevalent spermatogenetic arrest at the spermatocyte stage; the interstitial tissue was hypertrophic and the cytoplasm of the Leydig cells was full of lipid droplets. Ghrelin signal was present in the seminiferous tubules and, particularly, in the interstitial tissue of wt mice; however, in ksr1 -/- mice ghrelin expression was very weak in both the interstitial tissue and tubules. On the contrary, the signal of 3β-HSD was weak in the interstitial tissue of wt and strong in ksr1 -/- mice. Testosterone levels were significantly increased in the blood of ksr1 -/- mice (P <0.05) as compared with wt. The results obtained reveal the importance of the KSR scaffold proteins in the spermatogenetic process. The study of the molecular mechanisms associated with spermatogenetic defects in a mouse model is essential to understand the factors involved in human spermatogenesis.
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Affiliation(s)
- Elena Moretti
- Department of Molecular and Developmental Medicine, University of Siena, Policlinico Le Scotte, Viale Bracci, 14, 53100 Siena, Italy
| | - Giulia Collodel
- Department of Molecular and Developmental Medicine, University of Siena, Policlinico Le Scotte, Viale Bracci, 14, 53100 Siena, Italy; and Corresponding author
| | - Giuseppe Belmonte
- Department of Molecular and Developmental Medicine, University of Siena, Policlinico Le Scotte, Viale Bracci, 14, 53100 Siena, Italy
| | - Daria Noto
- Department of Molecular and Developmental Medicine, University of Siena, Policlinico Le Scotte, Viale Bracci, 14, 53100 Siena, Italy
| | - Emanuele Giurisato
- Department of Molecular and Developmental Medicine, University of Siena, Policlinico Le Scotte, Viale Bracci, 14, 53100 Siena, Italy; and Faculty of Biology, Medicine and Health, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
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6
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Frodyma D, Neilsen B, Costanzo-Garvey D, Fisher K, Lewis R. Coordinating ERK signaling via the molecular scaffold Kinase Suppressor of Ras. F1000Res 2017; 6:1621. [PMID: 29026529 PMCID: PMC5583734 DOI: 10.12688/f1000research.11895.1] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/01/2017] [Indexed: 12/17/2022] Open
Abstract
Many cancers, including those of the colon, lung, and pancreas, depend upon the signaling pathways induced by mutated and constitutively active Ras. The molecular scaffolds Kinase Suppressor of Ras 1 and 2 (KSR1 and KSR2) play potent roles in promoting Ras-mediated signaling through the Raf/MEK/ERK kinase cascade. Here we summarize the canonical role of KSR in cells, including its central role as a scaffold protein for the Raf/MEK/ERK kinase cascade, its regulation of various cellular pathways mediated through different binding partners, and the phenotypic consequences of KSR1 or KSR2 genetic inactivation. Mammalian KSR proteins have a demonstrated role in cellular and organismal energy balance with implications for cancer and obesity. Targeting KSR1 in cancer using small molecule inhibitors has potential for therapy with reduced toxicity to the patient. RNAi and small molecule screens using KSR1 as a reference standard have the potential to expose and target vulnerabilities in cancer. Interestingly, although KSR1 and KSR2 are similar in structure, KSR2 has a distinct physiological role in regulating energy balance. Although KSR proteins have been studied for two decades, additional analysis is required to elucidate both the regulation of these molecular scaffolds and their potent effect on the spatial and temporal control of ERK activation in health and disease.
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Affiliation(s)
- Danielle Frodyma
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Beth Neilsen
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Diane Costanzo-Garvey
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Kurt Fisher
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Robert Lewis
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska, USA.,Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska, USA
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7
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Neilsen BK, Frodyma DE, Lewis RE, Fisher KW. KSR as a therapeutic target for Ras-dependent cancers. Expert Opin Ther Targets 2017; 21:499-509. [PMID: 28333549 DOI: 10.1080/14728222.2017.1311325] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
INTRODUCTION Targeting downstream effectors required for oncogenic Ras signaling is a potential alternative or complement to the development of more direct approaches targeting Ras in the treatment of Ras-dependent cancers. Areas covered: Here we review literature pertaining to the molecular scaffold Kinase Suppressor of Ras (KSR) and its role in promoting signals critical to tumor maintenance. We summarize the phenotypes in knockout models, describe the role of KSR in cancer, and outline the structure and function of the KSR1 and KSR2 proteins. We then focus on the most recent literature that describes the crystal structure of the kinase domain of KSR2 in complex with MEK1, KSR-RAF dimerization particularly in response to RAF inhibition, and novel attempts to target KSR proteins directly. Expert opinion: KSR is a downstream effector of Ras-mediated tumorigenesis that is dispensable for normal growth and development, making it a desirable target for the development of novel therapeutics with a high therapeutic index. Recent advances have revealed that KSR can be functionally inhibited using a small molecule that stabilizes KSR in an inactive conformation. The efficacy and potential for this novel approach to be used clinically in the treatment of Ras-driven cancers is still being investigated.
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Affiliation(s)
- Beth K Neilsen
- a Eppley Institute, Fred & Pamela Buffett Cancer Center , University of Nebraska Medical Center , Omaha , NE , USA
| | - Danielle E Frodyma
- a Eppley Institute, Fred & Pamela Buffett Cancer Center , University of Nebraska Medical Center , Omaha , NE , USA
| | - Robert E Lewis
- a Eppley Institute, Fred & Pamela Buffett Cancer Center , University of Nebraska Medical Center , Omaha , NE , USA.,b Department of Pathology and Microbiology , University of Nebraska Medical Center , Omaha , NE , USA
| | - Kurt W Fisher
- b Department of Pathology and Microbiology , University of Nebraska Medical Center , Omaha , NE , USA
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8
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Guo L, Costanzo-Garvey DL, Smith DR, Neilsen BK, MacDonald RG, Lewis RE. Kinase Suppressor of Ras 2 (KSR2) expression in the brain regulates energy balance and glucose homeostasis. Mol Metab 2016; 6:194-205. [PMID: 28180061 PMCID: PMC5279912 DOI: 10.1016/j.molmet.2016.12.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 12/06/2016] [Accepted: 12/12/2016] [Indexed: 12/03/2022] Open
Abstract
Objective Kinase Suppressor of Ras 2 (KSR2) is a molecular scaffold coordinating Raf/MEK/ERK signaling that is expressed at high levels in the brain. KSR2 disruption in humans and mice causes obesity and insulin resistance. Understanding the anatomical location and mechanism of KSR2 function should lead to a better understanding of physiological regulation over energy balance. Methods Mice bearing floxed alleles of KSR2 (KSR2fl/fl) were crossed with mice expressing the Cre recombinase expressed by the Nestin promoter (Nes-Cre) to produce Nes-CreKSR2fl/fl mice. Growth, body composition, food consumption, cold tolerance, insulin and free fatty acid levels, glucose, and AICAR tolerance were measured in gender and age matched KSR2−/− mice Results Nes-CreKSR2fl/fl mice lack detectable levels of KSR2 in the brain. The growth and onset of obesity of Nes-CreKSR2fl/fl mice parallel those observed in KSR2−/− mice. As in KSR2−/− mice, Nes-CreKSR2fl/fl are glucose intolerant with elevated fasting and cold intolerance. Male Nes-CreKSR2fl/fl mice are hyperphagic, but female Nes-CreKSR2fl/fl mice are not. Unlike KSR2−/− mice, Nes-CreKSR2fl/fl mice respond normally to leptin and AICAR, which may explain why the degree of obesity of adult Nes-CreKSR2fl/fl mice is not as severe as that observed in KSR2−/− animals. Conclusions These observations suggest that, in the brain, KSR2 regulates energy balance via control of feeding behavior and adaptive thermogenesis, while a second KSR2-dependent mechanism, functioning through one or more other tissues, modulates sensitivity to leptin and activators of the energy sensor AMPK. Brain-specific KSR2 knockout causes obesity and glucose intolerance in both genders, but hyperphagia only in male mice. Brain-specific KSR2 knockout suppresses body temperature, before obesity. KSR2 in the brain regulates energy balance via control of feeding behavior and adaptive thermogenesis.
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Affiliation(s)
- Lili Guo
- Eppley Institute for Research in Cancer and Allied Diseases, 985950 Nebraska Medical Center, University of Nebraska Medical Center, Omaha, NE 68198-5950, USA; Fred & Pamela Buffett Cancer Center, 987696 Nebraska Medical Center, University of Nebraska Medical Center, Omaha, NE 68198-7696, USA.
| | - Diane L Costanzo-Garvey
- Eppley Institute for Research in Cancer and Allied Diseases, 985950 Nebraska Medical Center, University of Nebraska Medical Center, Omaha, NE 68198-5950, USA; Fred & Pamela Buffett Cancer Center, 987696 Nebraska Medical Center, University of Nebraska Medical Center, Omaha, NE 68198-7696, USA.
| | - Deandra R Smith
- Eppley Institute for Research in Cancer and Allied Diseases, 985950 Nebraska Medical Center, University of Nebraska Medical Center, Omaha, NE 68198-5950, USA; Fred & Pamela Buffett Cancer Center, 987696 Nebraska Medical Center, University of Nebraska Medical Center, Omaha, NE 68198-7696, USA.
| | - Beth K Neilsen
- Eppley Institute for Research in Cancer and Allied Diseases, 985950 Nebraska Medical Center, University of Nebraska Medical Center, Omaha, NE 68198-5950, USA; Fred & Pamela Buffett Cancer Center, 987696 Nebraska Medical Center, University of Nebraska Medical Center, Omaha, NE 68198-7696, USA.
| | - Richard G MacDonald
- Eppley Institute for Research in Cancer and Allied Diseases, 985950 Nebraska Medical Center, University of Nebraska Medical Center, Omaha, NE 68198-5950, USA; Fred & Pamela Buffett Cancer Center, 987696 Nebraska Medical Center, University of Nebraska Medical Center, Omaha, NE 68198-7696, USA; Department of Biochemistry and Molecular Biology, 985870 Nebraska Medical Center, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA.
| | - Robert E Lewis
- Eppley Institute for Research in Cancer and Allied Diseases, 985950 Nebraska Medical Center, University of Nebraska Medical Center, Omaha, NE 68198-5950, USA; Fred & Pamela Buffett Cancer Center, 987696 Nebraska Medical Center, University of Nebraska Medical Center, Omaha, NE 68198-7696, USA.
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9
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Cell non-autonomous regulation of hepatic IGF-1 and neonatal growth by Kinase Suppressor of Ras 2 (KSR2). Sci Rep 2016; 6:32093. [PMID: 27561547 PMCID: PMC4999994 DOI: 10.1038/srep32093] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 08/02/2016] [Indexed: 12/18/2022] Open
Abstract
Individuals with poor postnatal growth are at risk for cardiovascular and metabolic problems as adults. Here we show that disruption of the molecular scaffold Kinase Suppressor of Ras 2 (KSR2) causes selective inhibition of hepatic GH signaling in neonatal mice with impaired expression of IGF-1 and IGFBP3. ksr2(-/-) mice are normal size at birth but show a marked increase in FGF21 accompanied by reduced body mass, shortened body length, and reduced bone mineral density (BMD) and content (BMC) first evident during postnatal development. However, disrupting FGF21 in ksr2(-/-) mice does not normalize mass, length, or bone density and content in fgf21(-/-)ksr2(-/-) mice. Body length, BMC and BMD, but not body mass, are rescued by infection of two-day-old ksr2(-/-) mice with a recombinant adenovirus encoding human IGF-1. Relative to wild-type mice, GH injections reveal a significant reduction in JAK2 and STAT5 phosphorylation in liver, but not in skeletal muscle, of ksr2(-/-) mice. However, primary hepatocytes isolated from ksr2(-/-) mice show no reduction in GH-stimulated STAT5 phosphorylation. These data indicate that KSR2 functions in a cell non-autonomous fashion to regulate GH-stimulated IGF-1 expression in the liver of neonatal mice, which plays a key role in the development of body length.
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10
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Tekola-Ayele F, Doumatey AP, Shriner D, Bentley AR, Chen G, Zhou J, Fasanmade O, Johnson T, Oli J, Okafor G, Eghan BA, Agyenim-Boateng K, Adebamowo C, Amoah A, Acheampong J, Adeyemo A, Rotimi CN. Genome-wide association study identifies African-ancestry specific variants for metabolic syndrome. Mol Genet Metab 2015; 116:305-13. [PMID: 26507551 PMCID: PMC5292212 DOI: 10.1016/j.ymgme.2015.10.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 10/21/2015] [Accepted: 10/21/2015] [Indexed: 12/21/2022]
Abstract
The metabolic syndrome (MetS) is a constellation of metabolic disorders that increase the risk of developing several diseases including type 2 diabetes and cardiovascular diseases. Although genome-wide association studies (GWAS) have successfully identified variants associated with individual traits comprising MetS, the genetic basis and pathophysiological mechanisms underlying the clustering of these traits remain unclear. We conducted GWAS of MetS in 1427 Africans from Ghana and Nigeria followed by replication testing and meta-analysis in another continental African sample from Kenya. Further replication testing was performed in an African American sample from the Atherosclerosis Risk in Communities (ARIC) study. We found two African-ancestry specific variants that were significantly associated with MetS: SNP rs73989312[A] near CA10 that conferred increased risk (P=3.86 × 10(-8), OR=6.80) and SNP rs77244975[C] in CTNNA3 that conferred protection against MetS (P=1.63 × 10(-8), OR=0.15). Given the exclusive expression of CA10 in the brain, our CA10 finding strengthens previously reported link between brain function and MetS. We also identified two variants that are not African specific: rs76822696[A] near RALYL associated with increased MetS risk (P=7.37 × 10(-9), OR=1.59) and rs7964157[T] near KSR2 associated with reduced MetS risk (P=4.52 × 10(-8), Pmeta=7.82 × 10(-9), OR=0.53). The KSR2 locus displayed pleiotropic associations with triglyceride and measures of blood pressure. Rare KSR2 mutations have been reported to be associated with early onset obesity and insulin resistance. Finally, we replicated the LPL and CETP loci previously found to be associated with MetS in Europeans. These findings provide novel insights into the genetics of MetS in Africans and demonstrate the utility of conducting trans-ethnic disease gene mapping studies for testing the cosmopolitan significance of GWAS signals of cardio-metabolic traits.
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Affiliation(s)
- Fasil Tekola-Ayele
- Center for Research on Genomics and Global Health, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA.
| | - Ayo P Doumatey
- Center for Research on Genomics and Global Health, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Daniel Shriner
- Center for Research on Genomics and Global Health, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Amy R Bentley
- Center for Research on Genomics and Global Health, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Guanjie Chen
- Center for Research on Genomics and Global Health, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Jie Zhou
- Center for Research on Genomics and Global Health, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | | | | | - Johnnie Oli
- University of Nigeria Teaching Hospital, Enugu, Nigeria
| | | | - Benjami A Eghan
- University of Science and Technology, Department of Medicine, Kumasi, Ghana
| | | | - Clement Adebamowo
- Department of Epidemiology and Public Health, School of Medicine, University of Maryland, Baltimore, MD, USA
| | - Albert Amoah
- University of Ghana Medical School, Department of Medicine, Accra, Ghana
| | - Joseph Acheampong
- University of Science and Technology, Department of Medicine, Kumasi, Ghana
| | - Adebowale Adeyemo
- Center for Research on Genomics and Global Health, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Charles N Rotimi
- Center for Research on Genomics and Global Health, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA.
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Moretti E, Collodel G, Mazzi L, Russo I, Giurisato E. Ultrastructural study of spermatogenesis in KSR2 deficient mice. Transgenic Res 2015; 24:741-51. [DOI: 10.1007/s11248-015-9886-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 06/03/2015] [Indexed: 02/07/2023]
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