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Zegarra-Valdivia JA, Pignatelli J, Nuñez A, Torres Aleman I. The Role of Insulin-like Growth Factor I in Mechanisms of Resilience and Vulnerability to Sporadic Alzheimer's Disease. Int J Mol Sci 2023; 24:16440. [PMID: 38003628 PMCID: PMC10671249 DOI: 10.3390/ijms242216440] [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: 10/11/2023] [Revised: 11/06/2023] [Accepted: 11/14/2023] [Indexed: 11/26/2023] Open
Abstract
Despite decades of intense research, disease-modifying therapeutic approaches for Alzheimer's disease (AD) are still very much needed. Apart from the extensively analyzed tau and amyloid pathological cascades, two promising avenues of research that may eventually identify new druggable targets for AD are based on a better understanding of the mechanisms of resilience and vulnerability to this condition. We argue that insulin-like growth factor I (IGF-I) activity in the brain provides a common substrate for the mechanisms of resilience and vulnerability to AD. We postulate that preserved brain IGF-I activity contributes to resilience to AD pathology as this growth factor intervenes in all the major pathological cascades considered to be involved in AD, including metabolic impairment, altered proteostasis, and inflammation, to name the three that are considered to be the most important ones. Conversely, disturbed IGF-I activity is found in many AD risk factors, such as old age, type 2 diabetes, imbalanced diet, sedentary life, sociality, stroke, stress, and low education, whereas the Apolipoprotein (Apo) E4 genotype and traumatic brain injury may also be influenced by brain IGF-I activity. Accordingly, IGF-I activity should be taken into consideration when analyzing these processes, while its preservation will predictably help prevent the progress of AD pathology. Thus, we need to define IGF-I activity in all these conditions and develop a means to preserve it. However, defining brain IGF-I activity cannot be solely based on humoral or tissue levels of this neurotrophic factor, and new functionally based assessments need to be developed.
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Affiliation(s)
- Jonathan A. Zegarra-Valdivia
- Achucarro Basque Center for Neuroscience, 48940 Leioa, Spain;
- Biomedical Research Networking Center on Neurodegenerative Diseases (CIBERNED), 28029 Madrid, Spain;
- School of Medicine, Universidad Señor de Sipán, Chiclayo 14000, Peru
| | - Jaime Pignatelli
- Biomedical Research Networking Center on Neurodegenerative Diseases (CIBERNED), 28029 Madrid, Spain;
- Cajal Institute (CSIC), 28002 Madrid, Spain
| | - Angel Nuñez
- Department of Anatomy, Histology and Neuroscience, Universidad Autónoma de Madrid, 28049 Madrid, Spain;
| | - Ignacio Torres Aleman
- Achucarro Basque Center for Neuroscience, 48940 Leioa, Spain;
- Biomedical Research Networking Center on Neurodegenerative Diseases (CIBERNED), 28029 Madrid, Spain;
- Ikerbasque, Basque Foundation for Science, 48009 Bilbao, Spain
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Nuñez A, Zegarra-Valdivia J, Fernandez de Sevilla D, Pignatelli J, Torres Aleman I. The neurobiology of insulin-like growth factor I: From neuroprotection to modulation of brain states. Mol Psychiatry 2023; 28:3220-3230. [PMID: 37353586 DOI: 10.1038/s41380-023-02136-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 05/30/2023] [Accepted: 06/13/2023] [Indexed: 06/25/2023]
Abstract
After decades of research in the neurobiology of IGF-I, its role as a prototypical neurotrophic factor is undisputed. However, many of its actions in the adult brain indicate that this growth factor is not only involved in brain development or in the response to injury. Following a three-layer assessment of its role in the central nervous system, we consider that at the cellular level, IGF-I is indeed a bona fide neurotrophic factor, modulating along ontogeny the generation and function of all the major types of brain cells, contributing to sculpt brain architecture and adaptive responses to damage. At the circuit level, IGF-I modulates neuronal excitability and synaptic plasticity at multiple sites, whereas at the system level, IGF-I intervenes in energy allocation, proteostasis, circadian cycles, mood, and cognition. Local and peripheral sources of brain IGF-I input contribute to a spatially restricted, compartmentalized, and timed modulation of brain activity. To better define these variety of actions, we consider IGF-I a modulator of brain states. This definition aims to reconcile all aspects of IGF-I neurobiology, and may provide a new conceptual framework in the design of future research on the actions of this multitasking neuromodulator in the brain.
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Affiliation(s)
- A Nuñez
- Department of Anatomy, Histology and Neurosciences, Universidad Autónoma de Madrid, Madrid, Spain
| | - J Zegarra-Valdivia
- Achucarro Basque Center for Neuroscience, Leioa, Spain
- CIBERNED, Madrid, Spain
- Universidad Señor de Sipán, Chiclayo, Perú
| | - D Fernandez de Sevilla
- Department of Anatomy, Histology and Neurosciences, Universidad Autónoma de Madrid, Madrid, Spain
| | - J Pignatelli
- CIBERNED, Madrid, Spain
- Cajal Institute (CSIC), Madrid, Spain
| | - I Torres Aleman
- Achucarro Basque Center for Neuroscience, Leioa, Spain.
- CIBERNED, Madrid, Spain.
- Ikerbasque Science Foundation, Bilbao, Spain.
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Novaj A, Engel MG, Wang R, Mao K, Xue X, Amir Y, Atzmon G, Huffman DM. Dietary Walnuts Preserve Aspects of Health Span and Alter the Hippocampal Lipidome in Aged High-Fat Diet-Fed Mice. Int J Mol Sci 2023; 24:ijms24032314. [PMID: 36768636 PMCID: PMC9916809 DOI: 10.3390/ijms24032314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 01/14/2023] [Accepted: 01/16/2023] [Indexed: 01/26/2023] Open
Abstract
Evidence continues to accrue that aging and its diseases can be delayed by pharmacologic and dietary strategies that target the underlying hallmarks of the aging process. However, identifying simple, safe, and effective dietary strategies involving the incorporation of whole foods that may confer some protection against the aging process is also needed. Recent observational studies have suggested that nut consumption can reduce mortality risk in humans. Among these, walnuts are particularly intriguing, given their high content of n-3 fatty acids, fiber, and antioxidant and anti-inflammatory compounds. To this end, 12-month-old male CB6F1 mice were provided either a defined control low-fat diet (LFD), a control high-fat diet (HFD), or an isocaloric HFD containing 7.67% walnuts by weight (HFD + W), and measures of healthspan and related biochemical markers (n = 10-19 per group) as well as survival (n = 20 per group) were monitored. Mice provided the HFD or HFD + W demonstrated marked weight gain, but walnuts lowered baseline glucose (p < 0.05) and tended to temper the effects of HFD on liver weight gain (p < 0.05) and insulin tolerance (p = 0.1). Additional assays suggested a beneficial effect on some indicators of health with walnut supplementation, including preservation of exercise capacity and improved short-term working memory, as determined by Y maze (p = 0.02). However, no effect was observed via any diet on inflammatory markers, antioxidant capacity, or survival (p = 0.2). Ingenuity Pathway Analysis of the hippocampal transcriptome identified two processes predicted to be affected by walnuts and potentially linked to cognitive function, including estrogen signaling and lipid metabolism, with changes in the latter confirmed by lipidomic analysis. In summary, while walnuts did not significantly improve survival on a HFD, they tended to preserve features of healthspan in the context of a metabolic stressor with aging.
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Affiliation(s)
- Ardijana Novaj
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Institute for Aging Research, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Matthew G. Engel
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Institute for Aging Research, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Ruixuan Wang
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Institute for Aging Research, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Kai Mao
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Institute for Aging Research, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Xiaonan Xue
- Department of Epidemiology & Population Health, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Yam Amir
- Department of Human Biology, University of Haifa, Haifa 3498838, Israel
| | - Gil Atzmon
- Institute for Aging Research, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Department of Human Biology, University of Haifa, Haifa 3498838, Israel
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Derek M. Huffman
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Institute for Aging Research, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Correspondence: ; Tel.: +1-718-430-4278; Fax: +1-718-430-8922
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Eerola K, Longo F, Reinbothe TM, Richard JE, Shevchouk OT, López-Ferreras L, Mishra D, Asker M, Tolö J, Miranda C, Musovic S, Olofsson CS, Rorsman P, Skibicka KP. Hindbrain insulin controls feeding behavior. Mol Metab 2022; 66:101614. [PMID: 36244663 PMCID: PMC9637798 DOI: 10.1016/j.molmet.2022.101614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 10/10/2022] [Accepted: 10/11/2022] [Indexed: 11/08/2022] Open
Abstract
OBJECTIVE Pancreatic insulin was discovered a century ago, and this discovery led to the first lifesaving treatment for diabetes. While still controversial, nearly one hundred published reports suggest that insulin is also produced in the brain, with most focusing on hypothalamic or cortical insulin-producing cells. However, specific function for insulin produced within the brain remains poorly understood. Here we identify insulin expression in the hindbrain's dorsal vagal complex (DVC), and determine the role of this source of insulin in feeding and metabolism, as well as its response to diet-induced obesity in mice. METHODS To determine the contribution of Ins2-producing neurons to feeding behavior in mice, we used the cross of transgenic RipHER-cre mouse and channelrhodopsin-2 expressing animals, which allowed us to optogenetically stimulate neurons expressing Ins2 in vivo. To confirm the presence of insulin expression in Rip-labeled DVC cells, in situ hybridization was used. To ascertain the specific role of insulin in effects discovered via optogenetic stimulation a selective, CNS applied, insulin receptor antagonist was used. To understand the physiological contribution of insulin made in the hindbrain a virogenetic knockdown strategy was used. RESULTS Insulin gene expression and presence of insulin-promoter driven fluorescence in rat insulin promoter (Rip)-transgenic mice were detected in the hypothalamus, but also in the DVC. Insulin mRNA was present in nearly all fluorescently labeled cells in DVC. Diet-induced obesity in mice altered brain insulin gene expression, in a neuroanatomically divergent manner; while in the hypothalamus the expected obesity-induced reduction was found, in the DVC diet-induced obesity resulted in increased expression of the insulin gene. This led us to hypothesize a potentially divergent energy balance role of insulin in these two brain areas. To determine the acute impact of activating insulin-producing neurons in the DVC, optic stimulation of light-sensitive channelrhodopsin 2 in Rip-transgenic mice was utilized. Optogenetic photoactivation induced hyperphagia after acute activation of the DVC insulin neurons. This hyperphagia was blocked by central application of the insulin receptor antagonist S961, suggesting the feeding response was driven by insulin. To determine whether DVC insulin has a necessary contribution to feeding and metabolism, virogenetic insulin gene knockdown (KD) strategy, which allows for site-specific reduction of insulin gene expression in adult mice, was used. While chow-fed mice failed to reveal any changes of feeding or thermogenesis in response to the KD, mice challenged with a high-fat diet consumed less food. No changes in body weight were identified, possibly resulting from compensatory reduction in thermogenesis. CONCLUSIONS Together, our data suggest an important role for hindbrain insulin and insulin-producing cells in energy homeostasis.
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Affiliation(s)
- Kim Eerola
- Institute for Neuroscience and Physiology, University of Gothenburg, Sweden,Unit of Integrative Physiology and Pharmacology, Institute of Biomedicine, University of Turku, Finland
| | - Francesco Longo
- Institute for Neuroscience and Physiology, University of Gothenburg, Sweden
| | | | | | | | | | - Devesh Mishra
- Institute for Neuroscience and Physiology, University of Gothenburg, Sweden
| | - Mohammed Asker
- Institute for Neuroscience and Physiology, University of Gothenburg, Sweden
| | - Johan Tolö
- Institute for Neuroscience and Physiology, University of Gothenburg, Sweden
| | - Caroline Miranda
- Institute for Neuroscience and Physiology, University of Gothenburg, Sweden
| | - Saliha Musovic
- Institute for Neuroscience and Physiology, University of Gothenburg, Sweden
| | | | - Patrik Rorsman
- Institute for Neuroscience and Physiology, University of Gothenburg, Sweden,Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Karolina P. Skibicka
- Institute for Neuroscience and Physiology, University of Gothenburg, Sweden,Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Sweden,Department of Nutritional Sciences and The Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, USA,Corresponding author. Department of Physiology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Medicinaregatan 11, PO Box 434, SE-405 30, Gothenburg, Sweden. Fax: +46 31 786 3512.
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Gusmao DO, de Sousa ME, Tavares MR, Donato J. Increased GH Secretion and Body Growth in Mice Carrying Ablation of IGF-1 Receptor in GH-releasing Hormone Cells. Endocrinology 2022; 163:6696879. [PMID: 36099517 DOI: 10.1210/endocr/bqac151] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Indexed: 11/19/2022]
Abstract
Growth hormone (GH) secretion is controlled by short and long negative feedback loops. In this regard, both GH (short-loop feedback) and insulin-like growth factor 1 (IGF-1; long-loop feedback) can target somatotropic cells of the pituitary gland and neuroendocrine hypothalamic neurons to regulate the GH/IGF-1 axis. GH-releasing hormone (GHRH)-expressing neurons play a fundamental role in stimulating pituitary GH secretion. However, it is currently unknown whether IGF-1 action on GHRH-expressing cells is required for the control of the GH/IGF-1/growth axis. In the present study, we investigated the phenotype of male and female mice carrying ablation of IGF-1 receptor (IGF1R) exclusively in GHRH cells. After weaning, both male and female GHRHΔIGF1R mice exhibited increases in body weight, lean body mass, linear growth, and length of long bones (tibia, femur, humerus, and radius). In contrast, the percentage of body fat was similar between control and GHRHΔIGF1R mice. The higher body growth of GHRHΔIGF1R mice can be explained by increases in mean GH levels, GH pulse amplitude, and pulse frequency, calculated from 36 blood samples collected from each animal at 10-minute intervals. GHRHΔIGF1R mice also showed increased hypothalamic Ghrh mRNA levels, pituitary Gh mRNA expression, hepatic Igf1 expression, and serum IGF-1 levels compared with control animals. Furthermore, GHRHΔIGF1R mice displayed significant alterations in the sexually dimorphic hepatic gene expression profile, with a prevailing feminization in most genes analyzed. In conclusion, our findings indicate that GHRH neurons represent a key and necessary site for the long-loop negative feedback that controls the GH/IGF-1 axis and body growth.
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Affiliation(s)
- Daniela O Gusmao
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, Sao Paulo, SP 05508-000, Brazil
| | - Maria E de Sousa
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, Sao Paulo, SP 05508-000, Brazil
| | - Mariana R Tavares
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, Sao Paulo, SP 05508-000, Brazil
| | - Jose Donato
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, Sao Paulo, SP 05508-000, Brazil
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Engel MG, Smith J, Mao K, Quipildor GF, Cui MH, Gulinello M, Branch CA, Gandy SE, Huffman DM. Evidence for preserved insulin responsiveness in the aging rat brain. GeroScience 2022; 44:2491-2508. [PMID: 35798912 PMCID: PMC9768080 DOI: 10.1007/s11357-022-00618-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 06/27/2022] [Indexed: 01/06/2023] Open
Abstract
Insulin appears to exert salutary effects in the central nervous system (CNS). Thus, brain insulin resistance has been proposed to play a role in brain aging and dementia but is conceptually complex and unlikely to fit classic definitions established in peripheral tissues. Thus, we sought to characterize brain insulin responsiveness in young (4-5 months) and old (24 months) FBN male rats using a diverse set of assays to determine the extent to which insulin effects in the CNS are impaired with age. When performing hyperinsulinemic-euglycemic clamps in rats, intracerebroventricular (ICV) infusion of insulin in old animals improved peripheral insulin sensitivity by nearly two-fold over old controls and comparable to young rats, suggesting preservation of this insulin-triggered response in aging per se (p < 0.05). We next used an imaging-based approach by comparing ICV vehicle versus insulin and performed resting state functional magnetic resonance imaging (rs-fMRI) to evaluate age- and insulin-related changes in network connectivity within the default mode network. In aging, lower connectivity between the mesial temporal (MT) region and other areas, as well as reduced MT signal complexity, was observed in old rats, which correlated with greater cognitive deficits in old. Despite these stark differences, ICV insulin failed to elicit any significant alteration to the BOLD signal in young rats, while a significant deviation of the BOLD signal was observed in older animals, characterized by augmentation in regions of the septal nucleus and hypothalamus, and reduction in thalamus and nucleus accumbens. In contrast, ex vivo stimulation of hippocampus with 10 nM insulin revealed increased Akt activation in young (p < 0.05), but not old rats. Despite similar circulating levels of insulin and IGF-1, cerebrospinal fluid concentrations of these ligands were reduced with age. Thus, these data highlight the complexity of capturing brain insulin action and demonstrate preserved or heightened brain responses to insulin with age, despite dampened canonical signaling, thereby suggesting impaired CNS input of these ligands may be a feature of reduced brain insulin action, providing further rationale for CNS replacement strategies.
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Affiliation(s)
- Matthew G Engel
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Institute for Aging Research, Albert Einstein College of Medicine, 1300 Morris Park Ave, Golding Building Room 201, BronxBronx, NY, 10461, USA
| | - Jeremy Smith
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, USA
| | - Kai Mao
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Institute for Aging Research, Albert Einstein College of Medicine, 1300 Morris Park Ave, Golding Building Room 201, BronxBronx, NY, 10461, USA
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Gabriela Farias Quipildor
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Institute for Aging Research, Albert Einstein College of Medicine, 1300 Morris Park Ave, Golding Building Room 201, BronxBronx, NY, 10461, USA
| | - Min-Hui Cui
- Department of Radiology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Maria Gulinello
- Dominick S. Purpura Department of Neuroscience, Behavioral Core Facility, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Craig A Branch
- Department of Radiology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Samuel E Gandy
- Department of Neurology and the Mount Sinai Center for Cognitive Health, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Department of Psychiatry and the Mount Sinai Alzheimer's Disease Research Center, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Derek M Huffman
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
- Institute for Aging Research, Albert Einstein College of Medicine, 1300 Morris Park Ave, Golding Building Room 201, BronxBronx, NY, 10461, USA.
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
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dos Santos WO, Wasinski F, Tavares MR, Campos AMP, Elias CF, List EO, Kopchick JJ, Szawka RE, Donato J. Ablation of Growth Hormone Receptor in GABAergic Neurons Leads to Increased Pulsatile Growth Hormone Secretion. Endocrinology 2022; 163:6634255. [PMID: 35803590 PMCID: PMC9302893 DOI: 10.1210/endocr/bqac103] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Indexed: 11/19/2022]
Abstract
Growth hormone (GH) acts in several hypothalamic neuronal populations to modulate metabolism and the autoregulation of GH secretion via negative-feedback loops. However, few studies have investigated whether GH receptor (GHR) expression in specific neuronal populations is required for the homeostatic control of GH secretion and energy homeostasis. In the present study, we investigated the consequences of the specific GHR ablation in GABAergic (VGAT-expressing) or glutamatergic (VGLUT2-expressing) cells. GHR ablation in GABAergic neurons led to increased GH secretion, lean mass, and body growth in male and female mice. VGAT-specific GHR knockout (KO) male mice also showed increased serum insulin-like growth factor-1, hypothalamic Ghrh, and hepatic Igf1 messenger RNA levels. In contrast, normal GH secretion, but reduced lean body mass, was observed in mice carrying GHR ablation in glutamatergic neurons. GHR ablation in GABAergic cells increased weight loss and led to decreased blood glucose levels during food restriction, whereas VGLUT2-specific GHR KO mice showed blunted feeding response to 2-deoxy-D-glucose both in males and females, and increased relative food intake, oxygen consumption, and serum leptin levels in male mice. Of note, VGLUT2-cre female mice, independently of GHR ablation, exhibited a previously unreported phenotype of mild reduction in body weight without further metabolic alterations. The autoregulation of GH secretion via negative-feedback loops requires GHR expression in GABAergic cells. Furthermore, GHR ablation in GABAergic and glutamatergic neuronal populations leads to distinct metabolic alterations. These findings contribute to the understanding of the neuronal populations responsible for mediating the neuroendocrine and metabolic effects of GH.
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Affiliation(s)
- Willian O dos Santos
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de São Paulo, São Paulo, 05508-000, Brazil
| | - Frederick Wasinski
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de São Paulo, São Paulo, 05508-000, Brazil
| | - Mariana R Tavares
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de São Paulo, São Paulo, 05508-000, Brazil
| | - Ana M P Campos
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de São Paulo, São Paulo, 05508-000, Brazil
| | - Carol F Elias
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, 48109-5622, USA
| | - Edward O List
- Edison Biotechnology Institute and Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio, 45701, USA
| | - John J Kopchick
- Edison Biotechnology Institute and Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio, 45701, USA
| | - Raphael E Szawka
- Department of Physiology and Biophysics, Instituto de Ciencias Biologicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901, Brazil
| | - Jose Donato
- Correspondence: Jose Donato Jr, PhD, Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de São Paulo, Av. Prof Lineu Prestes, 1524, São Paulo, 05508-000, Brazil.
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Insulin-like Growth Factor I Couples Metabolism with Circadian Activity through Hypo-Thalamic Orexin Neurons. Int J Mol Sci 2022; 23:ijms23094679. [PMID: 35563069 PMCID: PMC9101627 DOI: 10.3390/ijms23094679] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/20/2022] [Accepted: 04/21/2022] [Indexed: 02/06/2023] Open
Abstract
Uncoupling of metabolism and circadian activity is associated with an increased risk of a wide spectrum of pathologies. Recently, insulin and the closely related insulin-like growth factor I (IGF-I) were shown to entrain feeding patterns with circadian rhythms. Both hormones act centrally to modulate peripheral glucose metabolism; however, whereas central targets of insulin actions are intensely scrutinized, those mediating the actions of IGF-I remain less defined. We recently showed that IGF-I targets orexin neurons in the lateral hypothalamus, and now we evaluated whether IGF-I modulates orexin neurons to align circadian rhythms with metabolism. Mice with disrupted IGF-IR activity in orexin neurons (Firoc mice) showed sexually dimorphic alterations in daily glucose rhythms and feeding activity patterns which preceded the appearance of metabolic disturbances. Thus, Firoc males developed hyperglycemia and glucose intolerance, while females developed obesity. Since IGF-I directly modulates orexin levels and hepatic expression of KLF genes involved in circadian and metabolic entrainment in an orexin-dependent manner, it seems that IGF-I entrains metabolism and circadian rhythms by modulating the activity of orexin neurons.
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Pérez-Matute P, López IP, Íñiguez M, Recio-Fernández E, Torrens R, Piñeiro-Hermida S, Alfaro-Arnedo E, Chau L, Walz C, Hoeflich A, Oteo JA, Pichel JG. IGF1R is a mediator of sex-specific metabolism in mice: Effects of age and high-fat diet. Front Endocrinol (Lausanne) 2022; 13:1033208. [PMID: 36353242 PMCID: PMC9638844 DOI: 10.3389/fendo.2022.1033208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 09/29/2022] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVE We aimed to investigate the short and long-term metabolic consequences of IGF1R systemic gene deficiency in mice. METHODS UBC-CreERT2, Igf1rfl/fl mutant mice were used to suppress IGF1R signaling in adult tissues by inducing postnatal generalized Igf1r deletion with tamoxifen. Animals were analyzed at two different ages: i) 13-weeks old young mice, and ii) 12-months old middle-aged mice. In addition, the effects of 10 weeks-long high-fat diet (HFD) were investigated in middle-aged mice. RESULTS Young IGF1R-deficient mice were insulin-resistant, with high IGF1, growth hormone (GH) and IGFBP3, as well as low IGFBP2 circulating levels. Males also presented increased triglycerides in liver. In contrast, middle-aged mice did not clearly show all of these alterations, suggesting possible compensatory effects. Middle-aged IGF1R-deficient male mice were able to counteract the negative effects induced by aging and HFD in adiposity, inflammation and glucose metabolism. A metabolic sexual dimorphism dependent on IGF1R was observed, especially in middle-aged mice. CONCLUSIONS These results demonstrate that IGF1R is involved in metabolic homeostasis, with effects modulated by diet-induced obesity and aging in a sex dependent manner. Thus, IGF1R deficiency in mice is proposed as a useful tool to understand metabolic alterations observed in patients with IGF1R gene deletions.
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Affiliation(s)
- Patricia Pérez-Matute
- Infectious Diseases, Microbiota and Metabolism Unit, Infectious Diseases Department, Center for Biomedical Research of La Rioja (CIBIR) -Hospital Universitario San Pedro, Logroño, Spain
- *Correspondence: Patricia Pérez-Matute,
| | - Icíar P. López
- Lung Cancer and Respiratory Diseases Unit. Fundación Rioja Salud, Center for Biomedical Research of La Rioja (CIBIR), Logroño, Spain
| | - María Íñiguez
- Infectious Diseases, Microbiota and Metabolism Unit, Infectious Diseases Department, Center for Biomedical Research of La Rioja (CIBIR) -Hospital Universitario San Pedro, Logroño, Spain
| | - Emma Recio-Fernández
- Infectious Diseases, Microbiota and Metabolism Unit, Infectious Diseases Department, Center for Biomedical Research of La Rioja (CIBIR) -Hospital Universitario San Pedro, Logroño, Spain
| | - Raquel Torrens
- Lung Cancer and Respiratory Diseases Unit. Fundación Rioja Salud, Center for Biomedical Research of La Rioja (CIBIR), Logroño, Spain
| | - Sergio Piñeiro-Hermida
- Miguel Servet Foundation-Navarra's Health Research Institute (IDISNA), Navarrabiomed Biomedical Research Center, Oncoimmunology Group, Pamplona, Spain
| | - Elvira Alfaro-Arnedo
- Lung Cancer and Respiratory Diseases Unit. Fundación Rioja Salud, Center for Biomedical Research of La Rioja (CIBIR), Logroño, Spain
| | - Luong Chau
- Institute for Genome Biology, Research Institute for Farm Animal Biology (FBN), Dummerstorf, Germany
| | - Christina Walz
- Institute for Genome Biology, Research Institute for Farm Animal Biology (FBN), Dummerstorf, Germany
| | - Andreas Hoeflich
- Institute for Genome Biology, Research Institute for Farm Animal Biology (FBN), Dummerstorf, Germany
| | - José A. Oteo
- Infectious Diseases, Microbiota and Metabolism Unit, Infectious Diseases Department, Center for Biomedical Research of La Rioja (CIBIR) -Hospital Universitario San Pedro, Logroño, Spain
| | - José G. Pichel
- Lung Cancer and Respiratory Diseases Unit. Fundación Rioja Salud, Center for Biomedical Research of La Rioja (CIBIR), Logroño, Spain
- Biomedical Research Networking Center on Respiratory Diseases (CIBERES), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
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Al-Samerria S, Radovick S. The Role of Insulin-like Growth Factor-1 (IGF-1) in the Control of Neuroendocrine Regulation of Growth. Cells 2021; 10:cells10102664. [PMID: 34685644 PMCID: PMC8534318 DOI: 10.3390/cells10102664] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 09/30/2021] [Accepted: 10/03/2021] [Indexed: 12/12/2022] Open
Abstract
In mammals, the neuroendocrine system, which includes the communication between the hypothalamus and the pituitary, plays a major role in controlling body growth and cellular metabolism. GH produced from the pituitary somatotroph is considered the master regulator of somatic development and involved, directly and indirectly, in carbohydrate and lipid metabolism via complex, yet well-defined, signaling pathways. GH production from the pituitary gland is primarily regulated by the counter-regulatory effects of the hypothalamic GHRH and SST hormones. The role of IGF-1 feedback regulation in GH production has been demonstrated by pharmacologic interventions and in genetically modified mouse models. In the present review, we discuss the role of IGF-1 in the regulation of the GH-axis as it controls somatic growth and metabolic homeostasis. We present genetically modified mouse models that maintain the integrity of the GH/GHRH-axis with the single exception of IGF-1 receptor (IGF-1R) deficiency in the hypothalamic GHRH neurons and somatotroph that reveals a novel mechanism controlling adipose tissues physiology and energy expenditure.
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