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Hao L, Khan MSH, Zu Y, Liu J, Wang S. Thermoneutrality Inhibits Thermogenic Markers and Exacerbates Nonalcoholic Fatty Liver Disease in Mice. Int J Mol Sci 2024; 25:8482. [PMID: 39126051 PMCID: PMC11312964 DOI: 10.3390/ijms25158482] [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: 06/30/2024] [Revised: 07/30/2024] [Accepted: 08/01/2024] [Indexed: 08/12/2024] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) affects over a third of the US population and 25% globally, with current treatments proving ineffective. This study investigates whether manipulating brown adipose tissue (BAT) and beige fat activity by housing C57BL/6J mice at thermoneutral (27 °C) or standard temperatures (22 °C) impacts NAFLD development. Male mice were fed either a chow diet (CHD) or a "fast food" diet (FFD) for 10 weeks. Mice at 27 °C had reduced food intake but increased body weight and plasma leptin levels. FFD-fed mice at 27 °C had greater liver weight (2.6 vs. 1.8 g), triglyceride content (7.6 vs. 3.9 mg/g), and hepatic steatosis compared to those at 22 °C. Gene expression of fatty acid synthase, sterol regulatory element-binding protein 1, and fatty acid translocase CD36 was elevated in FFD-fed mice at 27 °C, but not in CHD-fed mice. Thermoneutral housing also reduced expression of thermogenic markers in BAT and inguinal white adipose tissue (WAT) and caused BAT whitening. In conclusion, thermoneutrality inhibits thermogenic markers and exacerbates NAFLD. Activating BAT or promoting WAT browning via cold exposure or other stimuli may offer a strategy for managing NAFLD.
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Affiliation(s)
- Lei Hao
- Department of Nutritional Sciences, Texas Tech University, Lubbock, TX 79409, USA; (M.S.H.K.); (Y.Z.); (J.L.)
- Department of Allied and Public Health, Indiana University of Pennsylvania, Indian, PA 15705, USA
| | - Md Shahjalal Hossain Khan
- Department of Nutritional Sciences, Texas Tech University, Lubbock, TX 79409, USA; (M.S.H.K.); (Y.Z.); (J.L.)
| | - Yujiao Zu
- Department of Nutritional Sciences, Texas Tech University, Lubbock, TX 79409, USA; (M.S.H.K.); (Y.Z.); (J.L.)
| | - Jie Liu
- Department of Nutritional Sciences, Texas Tech University, Lubbock, TX 79409, USA; (M.S.H.K.); (Y.Z.); (J.L.)
| | - Shu Wang
- Department of Nutritional Sciences, Texas Tech University, Lubbock, TX 79409, USA; (M.S.H.K.); (Y.Z.); (J.L.)
- College of Health Solutions, Arizona State University, Phoenix, AZ 85004, USA
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2
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Fuller KNZ, Thyfault JP. Barriers in translating preclinical rodent exercise metabolism findings to human health. J Appl Physiol (1985) 2021; 130:182-192. [PMID: 33180643 PMCID: PMC7944931 DOI: 10.1152/japplphysiol.00683.2020] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 10/21/2020] [Accepted: 11/10/2020] [Indexed: 01/03/2023] Open
Abstract
Physical inactivity and low aerobic capacity are primary drivers of chronic disease pathophysiology and are independently associated with all-cause mortality. Conversely, increased physical activity and exercise are central to metabolic disease prevention and longevity. Although these relationships are well characterized in the literature, what remains incompletely understood are the mechanisms by which physical activity/exercise prevents disease. Given methodological constraints of clinical research, investigators must often rely on preclinical rodent models to investigate these potential underlying mechanisms. However, there are several key barriers to applying exercise metabolism findings from rodent models to human health. These barriers include housing temperature, nutrient metabolism, exercise modality, exercise testing, and sex differences. Increased awareness and understanding of these barriers will enhance the ability to impact human health through more appropriate experimental design and interpretation of data within the context of these factors.
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Affiliation(s)
- Kelly N Z Fuller
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas
| | - John P Thyfault
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Kansas Medical Center, Kansas City, Kansas
- Research Service Kansas City Veterans Affairs Medical Center, Kansas City, Kansas
- Center for Children's Healthy Lifestyles and Nutrition, Kansas City, Missouri
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3
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Turner RT, Philbrick KA, Wong CP, Gamboa AR, Branscum AJ, Iwaniec UT. Effects of Propranolol on Bone, White Adipose Tissue, and Bone Marrow Adipose Tissue in Mice Housed at Room Temperature or Thermoneutral Temperature. Front Endocrinol (Lausanne) 2020; 11:117. [PMID: 32256446 PMCID: PMC7089918 DOI: 10.3389/fendo.2020.00117] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 02/21/2020] [Indexed: 12/16/2022] Open
Abstract
Growing female mice housed at room temperature (22°C) weigh the same but differ in body composition compared to mice housed at thermoneutrality (32°C). Specifically, mice housed at room temperature have lower levels of white adipose tissue (WAT). Additionally, bone marrow adipose tissue (bMAT) and cancellous bone volume fraction in distal femur metaphysis are lower in room temperature-housed mice. The metabolic changes induced by sub-thermoneutral housing are associated with lower leptin levels in serum and higher levels of Ucp1 gene expression in brown adipose tissue. Although the precise mechanisms mediating adaptation to sub-thermoneutral temperature stress remain to be elucidated, there is evidence that increased sympathetic nervous system activity acting via β-adrenergic receptors plays an important role. We therefore evaluated the effect of the non-specific β-blocker propranolol (primarily β1 and β2 antagonist) on body composition, femur microarchitecture, and bMAT in growing female C57BL/6 mice housed at either room temperature or thermoneutral temperature. As anticipated, cancellous bone volume fraction, WAT and bMAT were lower in mice housed at room temperature. Propranolol had small but significant effects on bone microarchitecture (increased trabecular number and decreased trabecular spacing), but did not attenuate premature bone loss induced by room temperature housing. In contrast, propranolol treatment prevented housing temperature-associated differences in WAT and bMAT. To gain additional insight, we evaluated a panel of genes in tibia, using an adipogenesis PCR array. Housing temperature and treatment with propranolol had exclusive as well as shared effects on gene expression. Of particular interest was the finding that room temperature housing reduced, whereas propranolol increased, expression of the gene for acetyl-CoA carboxylase (Acacb), the rate-limiting step for fatty acid synthesis and a key regulator of β-oxidation. Taken together, these findings provide evidence that increased activation of β1 and/or β2 receptors contributes to reduced bMAT by regulating adipocyte metabolism, but that this pathway is unlikely to be responsible for premature cancellous bone loss in room temperature-housed mice.
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Affiliation(s)
- Russell T. Turner
- Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR, United States
- Center for Healthy Aging Research, Oregon State University, Corvallis, OR, United States
| | - Kenneth A. Philbrick
- Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR, United States
| | - Carmen P. Wong
- Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR, United States
| | - Amanda R. Gamboa
- Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR, United States
| | - Adam J. Branscum
- Biostatistics Program, School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR, United States
| | - Urszula T. Iwaniec
- Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR, United States
- Center for Healthy Aging Research, Oregon State University, Corvallis, OR, United States
- *Correspondence: Urszula T. Iwaniec
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Martin SA, Philbrick KA, Wong CP, Olson DA, Branscum AJ, Jump DB, Marik CK, DenHerder JM, Sargent JL, Turner RT, Iwaniec UT. Thermoneutral housing attenuates premature cancellous bone loss in male C57BL/6J mice. Endocr Connect 2019; 8:1455-1467. [PMID: 31590144 PMCID: PMC6865368 DOI: 10.1530/ec-19-0359] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 10/07/2019] [Indexed: 12/12/2022]
Abstract
Mice are a commonly used model to investigate aging-related bone loss but, in contrast to humans, mice exhibit cancellous bone loss prior to skeletal maturity. The mechanisms mediating premature bone loss are not well established. However, our previous work in female mice suggests housing temperature is a critical factor. Premature cancellous bone loss was prevented in female C57BL/6J mice by housing the animals at thermoneutral temperature (where basal rate of energy production is at equilibrium with heat loss). In the present study, we determined if the protective effects of thermoneutral housing extend to males. Male C57BL/6J mice were housed at standard room temperature (22°C) or thermoneutral (32°C) conditions from 5 (rapidly growing) to 16 (slowly growing) weeks of age. Mice housed at room temperature exhibited reductions in cancellous bone volume fraction in distal femur metaphysis and fifth lumbar vertebra; these effects were abolished at thermoneutral conditions. Mice housed at thermoneutral temperature had higher levels of bone formation in distal femur (based on histomorphometry) and globally (serum osteocalcin), and lower global levels of bone resorption (serum C-terminal telopeptide of type I collagen) compared to mice housed at room temperature. Thermoneutral housing had no impact on bone marrow adiposity but resulted in higher abdominal white adipose tissue and serum leptin. The overall magnitude of room temperature housing-induced cancellous bone loss did not differ between male (current study) and female (published data) mice. These findings highlight housing temperature as a critical experimental variable in studies using mice of either sex to investigate aging-related changes in bone metabolism.
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Affiliation(s)
- Stephen A Martin
- Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, USA
| | - Kenneth A Philbrick
- Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, USA
| | - Carmen P Wong
- Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, USA
| | - Dawn A Olson
- Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, USA
| | - Adam J Branscum
- Biostatistics Program, School of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, USA
| | - Donald B Jump
- Molecular Nutrition and Diabetes Research Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, USA
| | - Charles K Marik
- Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, USA
| | - Jonathan M DenHerder
- Carlson College of Veterinary Medicine, Oregon State University, Corvallis, Oregon, USA
| | - Jennifer L Sargent
- Carlson College of Veterinary Medicine, Oregon State University, Corvallis, Oregon, USA
| | - Russell T Turner
- Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, USA
- Center for Healthy Aging Research, Oregon State University, Corvallis, Oregon, USA
| | - Urszula T Iwaniec
- Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, USA
- Center for Healthy Aging Research, Oregon State University, Corvallis, Oregon, USA
- Correspondence should be addressed to U T Iwaniec:
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McKie GL, Medak KD, Knuth CM, Shamshoum H, Townsend LK, Peppler WT, Wright DC. Housing temperature affects the acute and chronic metabolic adaptations to exercise in mice. J Physiol 2019; 597:4581-4600. [PMID: 31297830 DOI: 10.1113/jp278221] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 06/14/2019] [Indexed: 12/21/2022] Open
Abstract
KEY POINTS Mice are commonly housed at room temperatures below their thermoneutral zone meaning they are exposed to chronic thermal stress. Endurance exercise induces browning and mitochondrial biogenesis in white adipose tissue of rodents, but there are conflicting reports of this phenomenon in humans. We hypothesized that the ambient room temperature at which mice are housed could partially explain these discrepant reports between humans and rodents. We housed mice at room temperature or thermoneutrality and studied their physiological responses to acute and chronic exercise. We found that thermoneutral housing altered running behaviour and glucose homeostasis, and further, that exercise-induced markers of mitochondrial biogenesis and the browning of white adipose tissue were reduced in mice housed at thermoneutrality. ABSTRACT Mice are often housed at temperatures below their thermoneutral zone resulting in compensatory increases in thermogenesis. Despite this, many studies report housing mice at room temperature (RT), likely for the convenience of the researchers studying them. As such, the conflicting reports between humans and rodents regarding the ability of exercise to increase mitochondrial and thermogenic markers in white adipose tissue may be explained by the often-overlooked variable, housing temperature. To test this hypothesis, we housed male C57BL/6 mice at RT (22°C) or thermoneutrality (TN) (29°C) with or without access to a voluntary running wheel for 6 weeks or subjected them to an acute exhaustive bout of treadmill running. We examined the gene expression and protein content of select mitochondrial and thermogenic markers in skeletal muscle, epididymal white adipose tissue (eWAT), inguinal white adipose tissue (iWAT) and brown adipose tissue (BAT). We also assessed adipocyte morphology and indices of glucose homeostasis. Housing temperature influenced glucose tolerance and insulin action in vivo, yet the beneficial effects of exercise, both acute and chronic, remained intact in eWAT, BAT and skeletal muscle irrespective of housing temperature. Housing mice at TN led to an attenuation of some of the effects of exercise on iWAT. Collectively, we present data characterizing the acute and chronic metabolic adaptations to exercise at different housing temperatures and demonstrate, for the first time, that temperature influences the ability of exercise to increase markers of mitochondrial biogenesis and the browning of white adipose tissue.
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Affiliation(s)
- Greg L McKie
- Department of Human Health & Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Kyle D Medak
- Department of Human Health & Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Carly M Knuth
- Department of Human Health & Nutritional Sciences, University of Guelph, Guelph, ON, Canada.,Sunnybrook Research Institute, University of Toronto, Toronto, ON, Canada
| | - Hesham Shamshoum
- Department of Human Health & Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Logan K Townsend
- Department of Human Health & Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Willem T Peppler
- Department of Human Health & Nutritional Sciences, University of Guelph, Guelph, ON, Canada.,Toronto General Hospital Research Institute, University Health Network, Toronto, ON, Canada
| | - David C Wright
- Department of Human Health & Nutritional Sciences, University of Guelph, Guelph, ON, Canada
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Small L, Gong H, Yassmin C, Cooney GJ, Brandon AE. Thermoneutral housing does not influence fat mass or glucose homeostasis in C57BL/6 mice. J Endocrinol 2018; 239:313-324. [PMID: 30400016 DOI: 10.1530/joe-18-0279] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 09/05/2018] [Indexed: 12/15/2022]
Abstract
One major factor affecting physiology often overlooked when comparing data from animal models and humans is the effect of ambient temperature. The majority of rodent housing is maintained at ~22°C, the thermoneutral temperature for lightly clothed humans. However, mice have a much higher thermoneutral temperature of ~30°C, consequently data collected at 22°C in mice could be influenced by animals being exposed to a chronic cold stress. The aim of this study was to investigate the effect of housing temperature on glucose homeostasis and energy metabolism of mice fed normal chow or a high-fat, obesogenic diet (HFD). Male C57BL/6J(Arc) mice were housed at standard temperature (22°C) or at thermoneutrality (29°C) and fed either chow or a 60% HFD for 13 weeks. The HFD increased fat mass and produced glucose intolerance as expected but this was not exacerbated in mice housed at thermoneutrality. Changing the ambient temperature, however, did alter energy expenditure, food intake, lipid content and glucose metabolism in skeletal muscle, liver and brown adipose tissue. Collectively, these findings demonstrate that mice regulate energy balance at different housing temperatures to maintain whole-body glucose tolerance and adiposity irrespective of the diet. Despite this, metabolic differences in individual tissues were apparent. In conclusion, dietary intervention in mice has a greater impact on adiposity and glucose metabolism than housing temperature although temperature is still a significant factor in regulating metabolic parameters in individual tissues.
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Affiliation(s)
- Lewin Small
- Diabetes and Metabolism Division, Garvan Institute, Sydney, New South Wales, Australia
| | - Henry Gong
- The University of Sydney, School of Medical Sciences, Charles Perkins Centre, Sydney, New South Wales, Australia
| | - Christian Yassmin
- The University of Sydney, School of Medical Sciences, Charles Perkins Centre, Sydney, New South Wales, Australia
| | - Gregory J Cooney
- Diabetes and Metabolism Division, Garvan Institute, Sydney, New South Wales, Australia
- The University of Sydney, School of Medical Sciences, Charles Perkins Centre, Sydney, New South Wales, Australia
| | - Amanda E Brandon
- Diabetes and Metabolism Division, Garvan Institute, Sydney, New South Wales, Australia
- The University of Sydney, School of Medical Sciences, Charles Perkins Centre, Sydney, New South Wales, Australia
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7
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van der Stelt I, Hoevenaars F, Široká J, de Ronde L, Friedecký D, Keijer J, van Schothorst E. Metabolic Response of Visceral White Adipose Tissue of Obese Mice Exposed for 5 Days to Human Room Temperature Compared to Mouse Thermoneutrality. Front Physiol 2017; 8:179. [PMID: 28386236 PMCID: PMC5362617 DOI: 10.3389/fphys.2017.00179] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 03/08/2017] [Indexed: 01/29/2023] Open
Abstract
Housing of laboratory mice at room temperature (22°C) might be considered a constant cold stress, which induces a thermogenic program in brown adipose tissue (BAT). However, the early adaptive response of white adipose tissue (WAT), the fat storage organ of the body, to a change from thermoneutrality to room temperature is not known. This was investigated here for various WAT depots, focusing on epididymal WAT (eWAT), widely used as reference depot. Male adult diet-induced obese (DIO) C57BL/6JOlaHsd mice housed at thermoneutrality (29°C), were for 5 days either switched to room temperature (22°C) or remained at thermoneutrality. Energy metabolism was continuously measured using indirect calorimetry. At the end of the study, serum metabolomics and WAT transcriptomics were performed. We confirmed activation of the thermogenic program in 22°C housed mice. Body weight and total fat mass were reduced. Whole body energy expenditure (EE) was increased, with a higher fatty acid to carbohydrate oxidation ratio and increased serum acylcarnitine levels, while energy intake was not significantly different between the two groups. Transcriptome analysis of eWAT identified tissue remodeling and inflammation as the most affected processes. Expression of pro-inflammatory M1 macrophage-related genes, and M1 over M2 macrophage ratio were decreased, which might be linked to an increased insulin sensitivity. Markers of thermogenesis were not altered in eWAT. Decreased expression of tryptophan hydroxylase 2 (Tph2) and cholecystokinin (Cck) might represent altered neuroendocrine signaling. eWAT itself does not show increased fatty acid oxidation. The three measured WATs, epididymal, mesenteric, and retroperitoneal, showed mainly similar responses; reduced inflammation (s100a8), decreased carbohydrate oxidation, and no or small differences in fatty acid oxidation. However, Ucp1 was only expressed and increased in rWAT in 22°C housed mice. Cck expression was decreased in the three WATs, significantly in eWAT and rWAT, in contrast to Tph2, which was decreased in eWAT while not expressed in mWAT and rWAT. Our data show that tissue remodeling, inflammation and neuroendocrine signaling are early responses in WAT to a moderate decrease in environmental temperature.
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Affiliation(s)
- Inge van der Stelt
- Human and Animal Physiology, Wageningen University Wageningen, Netherlands
| | - Femke Hoevenaars
- Human and Animal Physiology, Wageningen University Wageningen, Netherlands
| | - Jitka Široká
- Laboratory of Metabolomics, Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University Olomouc Olomouc, Czechia
| | - Lidwien de Ronde
- Human and Animal Physiology, Wageningen University Wageningen, Netherlands
| | - David Friedecký
- Laboratory of Metabolomics, Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University Olomouc Olomouc, Czechia
| | - Jaap Keijer
- Human and Animal Physiology, Wageningen University Wageningen, Netherlands
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Hylander BL, Eng JWL, Repasky EA. The Impact of Housing Temperature-Induced Chronic Stress on Preclinical Mouse Tumor Models and Therapeutic Responses: An Important Role for the Nervous System. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1036:173-189. [PMID: 29275472 PMCID: PMC9423006 DOI: 10.1007/978-3-319-67577-0_12] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In the last 10-15 years, there has been a recognition that the catecholamines (norepinephrine, NE, and epinephrine, Epi) released by the sympathetic nervous system under stressful conditions promote tumor growth through a variety of mechanisms. Tumors recruit autonomic nerves during their development and NE is then released locally in the tumor microenvironment (TME). Acting through adrenergic receptors present on a variety of cells in the TME, NE and Epi induce proliferation, resistance to apoptosis, epithelial to mesenchymal transition, metastasis of tumor cells, angiogenesis, and inflammation in the TME. These pre-clinical studies have been conducted in mouse models whose care and housing parameters are outlined in "The Guide for the Care and Use of Laboratory Animals [1]. In particular, the Guide mandates that mice be housed at standardized sub-thermoneutral temperatures; however, this causes a state of chronic cold-stress and elevated levels of NE. Although mice are able to maintain a normal body temperature when kept at these cool temperatures, it is becoming clear that this cold-stress is sufficient to activate physiological changes which affect experimental outcomes. We find that when mice are housed under standard, sub-thermoneutral temperatures (~22 °C, ST), tumor growth is significantly greater than when mice are housed at thermoneutrality (~30 °C TT). We also find that the anti-tumor immune response is suppressed at ST and this immunosuppression can be reversed by housing mice at TT or by administration of propranolol (a β-adrenergic receptor antagonist) to mice housed at ST. Furthermore, at ST tumors are more resistant to therapy and can also be sensitized to cytotoxic therapies by housing mice at TT or by treating mice with propranolol. The implications of these observations are particularly relevant to the way in which experiments conducted in preclinical models are interpreted and the findings implemented in the clinic. It may be that the disappointing failure of many new therapies to fulfill their promise in the clinic is related to an incomplete preclinical assessment in mouse models. Further, an expanded understanding of the efficacy of a therapy alone or in combination obtained by testing under a wider range of conditions would better predict how patients, who are under various levels of stress, might respond in a clinical setting. This may be particularly important to consider since we now appreciate that long term outcome of many therapies depends on eliciting an immune response.It is clear that the outcome of metabolic experiments, immunological investigations and therapeutic efficacy testing in tumors of mice housed at ST is restricted and expanding these experiments to include results obtained at TT may provide us with valuable information that would otherwise be overlooked.
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Affiliation(s)
- Bonnie L Hylander
- Department of Immunology, Roswell Park Cancer Institute, Buffalo, NY, USA
| | - Jason W-L Eng
- Department of Immunology, Roswell Park Cancer Institute, Buffalo, NY, USA
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Jun JC, Devera R, Unnikrishnan D, Shin MK, Bevans-Fonti S, Yao Q, Rathore A, Younas H, Halberg N, Scherer PE, Polotsky VY. Adipose HIF-1α causes obesity by suppressing brown adipose tissue thermogenesis. J Mol Med (Berl) 2016; 95:287-297. [PMID: 27738746 DOI: 10.1007/s00109-016-1480-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 09/27/2016] [Accepted: 10/06/2016] [Indexed: 12/18/2022]
Abstract
Hypoxia-inducible factor-1α (HIF-1α) in adipose tissue is known to promote obesity. We hypothesized that HIF-1α interferes with brown fat thermogenesis, thus decreasing energy expenditure. To test this hypothesis, we compared transgenic mice constitutively expressing HIF-1α in adipose tissues (HIF-1α++) at usual temperature (22 °C), where brown fat is somewhat active, or at thermoneutrality (30 °C), where brown fat is minimally active. HIF-1α++ mice or control litter mates were separated into room temperature (22 °C) or thermoneutrality (30 °C) groups. We assessed weight gain, food intake, calorimetry, activity, and oxygen consumption and transcriptional changes in isolated white and brown adipocytes. At 22 °C, HIF-1α++ mice exhibited accelerated weight gain, cold and glucose intolerance, hyperglycemia, and decreased energy expenditure without changes in food intake or activity. These changes were absent or minimal at thermoneutrality. In brown adipocytes of HIF-1α++ mice, oxygen consumption decreased ~50 % in association with reduced mitochondrial content, uncoupling protein 2, and peroxisome proliferator-activated receptor gamma coactivator 1 (PGC-1α). In conclusion, adipose HIF-1α overexpression inhibits thermogenesis and cellular respiration in brown adipose tissue, promoting obesity in the setting of reduced ambient temperature. KEY MESSAGE Constitutive HIF-1α activation in adipose tissue promotes weight gain in mice. The weight gain is associated with reduced brown adipose tissue function and oxygen consumption. Reduced oxygen consumption may be mediated by reductions in mitochondria.
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Affiliation(s)
- Jonathan C Jun
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins, University School of Medicine, 5501 Hopkins Bayview Circle Room 4A30A, Baltimore, MD, 21224, USA.
| | - Ronald Devera
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins, University School of Medicine, 5501 Hopkins Bayview Circle Room 4A30A, Baltimore, MD, 21224, USA
| | - Dileep Unnikrishnan
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins, University School of Medicine, 5501 Hopkins Bayview Circle Room 4A30A, Baltimore, MD, 21224, USA
| | - Mi-Kyung Shin
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins, University School of Medicine, 5501 Hopkins Bayview Circle Room 4A30A, Baltimore, MD, 21224, USA
| | - Shannon Bevans-Fonti
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins, University School of Medicine, 5501 Hopkins Bayview Circle Room 4A30A, Baltimore, MD, 21224, USA
| | - Qiaoling Yao
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins, University School of Medicine, 5501 Hopkins Bayview Circle Room 4A30A, Baltimore, MD, 21224, USA
| | - Aman Rathore
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins, University School of Medicine, 5501 Hopkins Bayview Circle Room 4A30A, Baltimore, MD, 21224, USA
| | - Haris Younas
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins, University School of Medicine, 5501 Hopkins Bayview Circle Room 4A30A, Baltimore, MD, 21224, USA
| | - Nils Halberg
- Touchstone Diabetes Center, Departments of Internal Medicine and Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Philipp E Scherer
- Touchstone Diabetes Center, Departments of Internal Medicine and Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Vsevolod Y Polotsky
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins, University School of Medicine, 5501 Hopkins Bayview Circle Room 4A30A, Baltimore, MD, 21224, USA
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10
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Arsenijevic D, Cajot JF, Fellay B, Dulloo AG, Van Vliet BN, Montani JP. Uninephrectomy-Induced Lipolysis and Low-Grade Inflammation Are Mimicked by Unilateral Renal Denervation. Front Physiol 2016; 7:227. [PMID: 27378937 PMCID: PMC4906570 DOI: 10.3389/fphys.2016.00227] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 05/30/2016] [Indexed: 12/13/2022] Open
Abstract
Uninephrectomy (UniNX) in rats on a fixed food intake leads to increased lipolysis and a low-grade inflammation with an increased subset of circulating cytokines. Because UniNX ablates renal nerves on the side of the removed kidney, we tested the contribution of unilateral renal denervation in the phenotype of UniNX. We compared Sham-operated controls, left nephrectomy (UniNX) and unilateral left kidney denervation (uDNX) in rats 4 weeks after surgery. uDNX did not affect kidney weight and function. In general, the uDNX phenotype was similar to the UniNX phenotype especially for lipolysis in fat pads and increased low-grade inflammation. uDNX led to decreased fat pad weight and increased hormone sensitive lipase and adipocyte triglyceride lipase mRNA levels in epididymal and inguinal adipose tissue, as well as increased circulating lipolysis markers β-hydroxybutyrate and glycerol. Measured circulating hormones such as leptin, T3 and insulin were similar amongst the three groups. The lipolytic cytokines interferon-gamma and granulocyte macrophage colony stimulating factor were increased in the circulation of both uDNX and UniNX groups. These two cytokines were also elevated in the spleen of both groups, but contrastingly they were decreased in fat pads, liver, and kidneys. Both uDNX and UniNX similarly increased noradrenaline content in fat pads and spleen. Melanocortin 4 receptor mRNA levels were increased in the brains of both uDNX and UniNX compared to Sham and may contribute to increased tissue noradrenaline levels. In addition, the farnesoid x receptor (FXR) may contribute to changes in tissue metabolism and inflammation, as anti-inflammatory FXR was decreased in the spleen but increased in other tissues in uDNX and UniNX compared to Sham. In summary, both uDNX and UniNX in rats promote metabolic and immunological alterations by mechanisms that seem to implicate modification of unilateral renal nerve pathways as well as central and peripheral neural pathways.
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Affiliation(s)
- Denis Arsenijevic
- Division of Physiology, Department of Medicine, University of FribourgFribourg, Switzerland; National Center of Competence in Research (Kidney.CH)Zurich, Switzerland
| | - Jean-François Cajot
- Division of Physiology, Department of Medicine, University of Fribourg Fribourg, Switzerland
| | - Benoit Fellay
- Chemistry/Hematology Laboratory, Fribourg Hospital Fribourg, Switzerland
| | - Abdul G Dulloo
- Division of Physiology, Department of Medicine, University of Fribourg Fribourg, Switzerland
| | - Bruce N Van Vliet
- BioMedical Sciences Division, Faculty of Medicine, Memorial University St. John's, NL, Canada
| | - Jean-Pierre Montani
- Division of Physiology, Department of Medicine, University of FribourgFribourg, Switzerland; National Center of Competence in Research (Kidney.CH)Zurich, Switzerland
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11
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Hylander BL, Repasky EA. Thermoneutrality, Mice, and Cancer: A Heated Opinion. Trends Cancer 2016; 2:166-175. [PMID: 28741570 DOI: 10.1016/j.trecan.2016.03.005] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 03/10/2016] [Accepted: 03/11/2016] [Indexed: 12/31/2022]
Abstract
The 'mild' cold stress caused by standard sub-thermoneutral housing temperatures used for laboratory mice in research institutes is sufficient to significantly bias conclusions drawn from murine models of several human diseases. We review the data leading to this conclusion, discuss the implications for research and suggest ways to reduce problems in reproducibility and experimental transparency caused by this housing variable. We have found that these cool temperatures suppress endogenous immune responses, skewing tumor growth data and the severity of graft versus host disease, and also increase the therapeutic resistance of tumors. Owing to the potential for ambient temperature to affect energy homeostasis as well as adrenergic stress, both of which could contribute to biased outcomes in murine cancer models, housing temperature should be reported in all publications and considered as a potential source of variability in results between laboratories. Researchers and regulatory agencies should work together to determine whether changes in housing parameters would enhance the use of mouse models in cancer research, as well as for other diseases. Finally, for many years agencies such as the National Cancer Institute (NCI) have encouraged the development of newer and more sophisticated mouse models for cancer research, but we believe that, without an appreciation of how basic murine physiology is affected by ambient temperature, even data from these models is likely to be compromised.
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Affiliation(s)
- Bonnie L Hylander
- Roswell Park Cancer Institute, Department of Immunology, Elm and Carlton Streets, Buffalo, NY 14263-0001, USA
| | - Elizabeth A Repasky
- Roswell Park Cancer Institute, Department of Immunology, Elm and Carlton Streets, Buffalo, NY 14263-0001, USA.
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12
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Eng JWL, Reed CB, Kokolus KM, Repasky EA. Housing temperature influences the pattern of heat shock protein induction in mice following mild whole body hyperthermia. Int J Hyperthermia 2015; 30:540-6. [PMID: 25430986 DOI: 10.3109/02656736.2014.981300] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
PURPOSE Researchers studying the murine response to stress generally use mice housed under standard, nationally mandated conditions as controls. Few investigators are concerned whether basic physical aspects of mouse housing could be an additional source of stress, capable of influencing the subsequent impact of an experimentally applied stressor. We have recently become aware of the potential for housing conditions to impact important physiological and immunological properties in mice. MATERIALS AND METHODS Here we sought to determine whether housing mice at standard temperature (ST; 22 °C) vs. thermoneutral temperature (TT; 30 °C) influences baseline expression of heat shock proteins (HSPs) and their typical induction following a whole body heating. RESULTS There were no significant differences in baseline expression of HSPs at ST and TT. However, in several cases, the induction of Hsp70, Hsp110 and Hsp90 in tissues of mice maintained at ST was greater than at TT following 6 h of heating (which elevated core body temperature to 39.5 °C). This loss of HSP induction was also seen when mice housed at ST were treated with propranolol, a β-adrenergic receptor antagonist, used clinically to treat hypertension and stress. CONCLUSIONS Taken together, these data show that housing temperature significantly influences the expression of HSPs in mice after whole body heating and thus should be considered when stress responses are studied in mice.
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Affiliation(s)
- Jason W-L Eng
- Department of Immunology, Roswell Park Cancer Institute , Buffalo, New York , USA
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13
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Dudele A, Rasmussen GM, Mayntz D, Malte H, Lund S, Wang T. Effects of ambient temperature on glucose tolerance and insulin sensitivity test outcomes in normal and obese C57 male mice. Physiol Rep 2015; 3:3/5/e12396. [PMID: 25991720 PMCID: PMC4463826 DOI: 10.14814/phy2.12396] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Mice are commonly used as animal models to study human metabolic diseases, but experiments are typically performed at room temperature, which is far below their thermoneutral zone and is associated with elevated heart rate, food intake, and energy expenditure. We set out to study how ambient temperature affects glucose tolerance and insulin sensitivity in control and obese male mice. Adult male C57BL/6J mice were housed at room temperature (23°C) for 6 weeks and fed either control or high fat diet. They were then fasted for 6 h before glucose or insulin tolerance tests were performed at 15, 20, 25, or 30°C. To ensure that behavioral thermoregulation did not counterbalance the afflicted ambient temperatures, oxygen consumption was determined on mice with the same thermoregulatory opportunities as during the tests. Decreasing ambient temperatures increased oxygen consumption and body mass loss during fasting in both groups. Mice fed high fat diet had improved glucose tolerance at 30°C and increased levels of fasting insulin followed by successive decrease of fasting glucose. However, differences between control and high-fat diet mice were present at all temperatures. Ambient temperature did not affect glucose tolerance in control group and insulin tolerance in either of the groups. Ambient temperature affects glucose metabolism in mice and this effect is phenotype specific.
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Affiliation(s)
- Anete Dudele
- Section for Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - Gitte Marie Rasmussen
- Section for Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - David Mayntz
- Research and Innovation, VIA University College, Aarhus, Denmark
| | - Hans Malte
- Section for Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - Sten Lund
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Tobias Wang
- Section for Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
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14
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Dumke CL, Slivka DR, Cuddy JS, Hailes WS, Rose SM, Ruby BC. The Effect of Environmental Temperature on Glucose and Insulin After an Oral Glucose Tolerance Test in Healthy Young Men. Wilderness Environ Med 2015; 26:335-42. [PMID: 25937547 DOI: 10.1016/j.wem.2015.03.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 02/04/2015] [Accepted: 03/02/2015] [Indexed: 11/26/2022]
Abstract
OBJECTIVE The purpose of this study was to compare glucose and insulin responses during an oral glucose tolerance test (OGTT) in cold (C), neutral (N), and hot (H) environments. METHODS Eleven males completed three 4-hour climate-controlled OGTT trials (C, 7.2°C; N, 22°C; and H, 43°C). Participants remained semireclined for 60 minutes before ingesting a 1.8 g/kg glucose beverage. Skin and rectal core temperatures were continuously monitored. Blood was collected just before glucose ingestion (time 0) and at 15, 30, 60, 90, 120, and 180 minutes, and analyzed for serum glucose, insulin, hematocrit, and hemoglobin. Expired gases were collected upon entering the chamber (-60 minutes), before glucose ingestion (0 minutes), and at 60, 120, and 180 minutes to determine V(O2) and respiratory exchange ratio. RESULTS Rectal core temperature was greater in the H condition compared with both C and N (P < .001). Rectal core temperature was not different between C and N, whereas skin temperature was different across all trials (H greater than N greater than C). The V(O2) was greater in C than in both H and N during all time points. Carbohydrate oxidation was greater in C compared with H and N (P < 0.001). Glucose was higher during H compared with C and N (P ≤ 0.002). Glucose was elevated in C compared with N. Insulin was higher in H compared with C (P = 0.009). Area under the curve for serum glucose was greater in H compared with C and N (P ≤ 0.001); however, there was no significant difference in area under the curve for insulin. CONCLUSIONS These data indicate that after an OGTT, glucose and insulin are elevated in a hot environment.
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Affiliation(s)
- Charles L Dumke
- Department of Health and Human Performance, Montana Center for Work Physiology and Exercise Metabolism, University of Montana, Missoula, MT (Drs Dumke and Ruby, and Messrs. Cuddy, Hailes, and Rose).
| | - Dustin R Slivka
- School of Health, Physical Education and Recreation, University of Nebraska at Omaha, Omaha, NE (Dr Slivka)
| | - John S Cuddy
- Department of Health and Human Performance, Montana Center for Work Physiology and Exercise Metabolism, University of Montana, Missoula, MT (Drs Dumke and Ruby, and Messrs. Cuddy, Hailes, and Rose)
| | - Walter S Hailes
- Department of Health and Human Performance, Montana Center for Work Physiology and Exercise Metabolism, University of Montana, Missoula, MT (Drs Dumke and Ruby, and Messrs. Cuddy, Hailes, and Rose)
| | - Shawn M Rose
- Department of Health and Human Performance, Montana Center for Work Physiology and Exercise Metabolism, University of Montana, Missoula, MT (Drs Dumke and Ruby, and Messrs. Cuddy, Hailes, and Rose)
| | - Brent C Ruby
- Department of Health and Human Performance, Montana Center for Work Physiology and Exercise Metabolism, University of Montana, Missoula, MT (Drs Dumke and Ruby, and Messrs. Cuddy, Hailes, and Rose)
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15
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Waernbaum I, Dahlquist G. Low mean temperature rather than few sunshine hours are associated with an increased incidence of type 1 diabetes in children. Eur J Epidemiol 2015; 31:61-5. [DOI: 10.1007/s10654-015-0023-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 03/20/2015] [Indexed: 10/23/2022]
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16
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Standard sub-thermoneutral caging temperature influences radiosensitivity of hematopoietic stem and progenitor cells. PLoS One 2015; 10:e0120078. [PMID: 25793392 PMCID: PMC4368554 DOI: 10.1371/journal.pone.0120078] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 01/19/2015] [Indexed: 11/19/2022] Open
Abstract
The production of new blood cells relies on a hierarchical network of hematopoietic stem and progenitor cells (HSPCs). To maintain lifelong hematopoiesis, HSPCs must be protected from ionizing radiation or other cytotoxic agents. For many years, murine models have been a valuable source of information regarding factors that either enhance or reduce the survival of HSPCs after exposure of marrow to ionizing radiation. In a recent series of studies, however, it has become clear that housing-related factors such as the cool room temperature required for laboratory mice can exert a surprising influence on the outcome of experiments. Here we report that the mild, but chronic cold-stress endured by mice housed under these conditions exerts a protective effect on HSPCs after both non-lethal and lethal doses of total body irradiation (TBI). Alleviation of this cold-stress by housing mice at a thermoneutral temperature (30°C) resulted in significantly greater baseline radiosensitivity to a lethal dose of TBI with more HSPCs from mice housed at thermoneutral temperature undergoing apoptosis following non-lethal TBI. Cold-stressed mice have elevated levels of norepinephrine, a key molecule of the sympathetic nervous system that binds to β-adrenergic receptors. We show that blocking this signaling pathway in vivo through use of the β-blocker propanolol completely mitigates the protective effect of cold-stress on HSPC apoptosis. Collectively this study demonstrates that chronic stress endured by the standard housing conditions of laboratory mice increases the resistance of HSPCs to TBI-induced apoptosis through a mechanism that depends upon β-adrenergic signaling. Since β-blockers are commonly prescribed to a wide variety of patients, this information could be important when predicting the clinical impact of HSPC sensitivity to TBI.
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17
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Housing temperature-induced stress drives therapeutic resistance in murine tumour models through β2-adrenergic receptor activation. Nat Commun 2015; 6:6426. [PMID: 25756236 DOI: 10.1038/ncomms7426] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 01/28/2015] [Indexed: 01/04/2023] Open
Abstract
Cancer research relies heavily on murine models for evaluating the anti-tumour efficacy of therapies. Here we show that the sensitivity of several pancreatic tumour models to cytotoxic therapies is significantly increased when mice are housed at a thermoneutral ambient temperature of 30 °C compared with the standard temperature of 22 °C. Further, we find that baseline levels of norepinephrine as well as the levels of several anti-apoptotic molecules are elevated in tumours from mice housed at 22 °C. The sensitivity of tumours to cytotoxic therapies is also enhanced by administering a β-adrenergic receptor antagonist to mice housed at 22 °C. These data demonstrate that standard housing causes a degree of cold stress sufficient to impact the signalling pathways related to tumour-cell survival and affect the outcome of pre-clinical experiments. Furthermore, these data highlight the significant role of host physiological factors in regulating the sensitivity of tumours to therapy.
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18
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Eng JWL, Kokolus KM, Reed CB, Hylander BL, Ma WW, Repasky EA. A nervous tumor microenvironment: the impact of adrenergic stress on cancer cells, immunosuppression, and immunotherapeutic response. Cancer Immunol Immunother 2014; 63:1115-28. [PMID: 25307152 DOI: 10.1007/s00262-014-1617-9] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 09/27/2014] [Indexed: 02/06/2023]
Abstract
Long conserved mechanisms maintain homeostasis in living creatures in response to a variety of stresses. However, continuous exposure to stress can result in unabated production of stress hormones, especially catecholamines, which can have detrimental health effects. While the long-term effects of chronic stress have well-known physiological consequences, recent discoveries have revealed that stress may affect therapeutic efficacy in cancer. Growing epidemiological evidence reveals strong correlations between progression-free and long-term survival and β-blocker usage in cancer patients. In this review, we summarize the current understanding of how the catecholamines, epinephrine and norepinephrine, affect cancer cell survival and tumor progression. We also highlight new data exploring the potential contributions of stress to immunosuppression in the tumor microenvironment and the implications of these findings for the efficacy of immunotherapies.
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Affiliation(s)
- Jason W-L Eng
- Department of Immunology, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY, 14263, USA
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19
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Messmer MN, Kokolus KM, Eng JWL, Abrams SI, Repasky EA. Mild cold-stress depresses immune responses: Implications for cancer models involving laboratory mice. Bioessays 2014; 36:884-91. [PMID: 25066924 DOI: 10.1002/bies.201400066] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Physiologically accurate mouse models of cancer are critical in the pre-clinical development of novel cancer therapies. However, current standardized animal-housing temperatures elicit chronic cold-associated stress in mice, which is further increased in the presence of tumor. This cold-stress significantly impacts experimental outcomes. Data from our lab and others suggest standard housing fundamentally alters murine physiology, and this can produce altered immune baselines in tumor and other disease models. Researchers may thus underestimate the efficacy of therapies that are benefitted by immune responses. A potential mediator, norepinephrine, also underlies stress pathways common in mice and humans. Therefore, research into mechanisms connecting cold-stress and norepinephrine signaling with immune depression in mice could highlight new combination therapies for humans to simultaneously target stress while stimulating anti-tumor immunity.
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Affiliation(s)
- Michelle N Messmer
- Department of Immunology, Roswell Park Cancer Institute, Buffalo, NY, USA
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20
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Abstract
Fasting of mice is a common procedure performed in association with many different types of experiments mainly in order to reduce variability in investigatory parameters or to facilitate surgical procedures. However, the effects of fasting not directly related to the investigatory parameters are often ignored. The aim of this review is to present and summarize knowledge about the effects of fasting of mice to facilitate optimization of the fasting procedure for any given study and thereby maximize the scientific outcome and minimize the discomfort for the mice and hence ensure high animal welfare. The results are presented from a number of experimental studies, providing evidence for fasting-induced changes in hormone balance, body weight, metabolism, hepatic enzymes, cardiovascular parameters, body temperature and toxicological responses. A description of relevant normal behaviour and standard physiological parameters is given, concluding that mice are primarily nocturnal and consume two-thirds of their total food intake during the night. It is argued that overnight fasting of mice is not comparable with overnight fasting of humans because the mouse has a nocturnal circadian rhythm and a higher metabolic rate. It is suggested that because many physiological parameters are regulated by circadian rhythms, fasting initiated at different points in the circadian rhythm has different impacts and produces different results.
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Affiliation(s)
- T L Jensen
- Novo Nordisk, Animal Unit, Maaloev, Denmark
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21
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Grimpo K, Völker MN, Heppe EN, Braun S, Heverhagen JT, Heldmaier G. Brown adipose tissue dynamics in wild-type and UCP1-knockout mice: in vivo insights with magnetic resonance. J Lipid Res 2014; 55:398-409. [PMID: 24343897 PMCID: PMC3934725 DOI: 10.1194/jlr.m042895] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 12/06/2013] [Indexed: 01/12/2023] Open
Abstract
We used noninvasive magnetic resonance imaging (MRI) and magnetic resonance spectroscopy to compare interscapular brown adipose tissue (iBAT) of wild-type (WT) and uncoupling protein 1 (UCP1)-knockout mice lacking UCP1-mediated nonshivering thermogenesis (NST). Mice were sequentially acclimated to an ambient temperature of 30°C, 18°C, and 5°C. We detected a remodeling of iBAT and a decrease in its lipid content in all mice during cold exposure. Ratios of energy-rich phosphates (ATP/ADP, phosphocreatine/ATP) in iBAT were maintained stable during noradrenergic stimulation of thermogenesis in cold- and warm-adapted mice and no difference between the genotypes was observed. As free fatty acids (FFAs) serve as fuel for thermogenesis and activate UCP1 for uncoupling of oxidative phosphorylation, brown adipose tissue is considered to be a main acceptor and consumer of FFAs. We measured a major loss of FFAs from iBAT during noradrenergic stimulation of thermogenesis. This mobilization of FFAs was observed in iBAT of WT mice as well as in mice lacking UCP1. The high turnover and the release of FFAs from iBAT suggests an enhancement of lipid metabolism, which in itself contributes to the sympathetically activated NST and which is independent from uncoupled respiration mediated by UCP1. Our study demonstrates that MRI, besides its potential for visualizing and quantification of fat tissue, is a valuable tool for monitoring functional in vivo processes like lipid and phosphate metabolism during NST.
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Affiliation(s)
- Kirsten Grimpo
- Faculty of Biology, Department of Animal Physiology, Philipps-Universität Marburg, 35043 Marburg, Germany
| | - Maximilian N. Völker
- Faculty of Medicine, Department of Diagnostic Radiology, Philipps-Universität Marburg, 35043 Marburg, Germany
| | - Eva N. Heppe
- Faculty of Biology, Department of Animal Physiology, Philipps-Universität Marburg, 35043 Marburg, Germany
| | - Steve Braun
- Faculty of Medicine, Department of Diagnostic Radiology, Philipps-Universität Marburg, 35043 Marburg, Germany
| | - Johannes T. Heverhagen
- Institute for Diagnostic, Interventional, and Paediatric Radiology, University Hospital Inselspital, Bern, Switzerland
| | - Gerhard Heldmaier
- Faculty of Biology, Department of Animal Physiology, Philipps-Universität Marburg, 35043 Marburg, Germany
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Kokolus KM, Spangler HM, Povinelli BJ, Farren MR, Lee KP, Repasky EA. Stressful presentations: mild cold stress in laboratory mice influences phenotype of dendritic cells in naïve and tumor-bearing mice. Front Immunol 2014; 5:23. [PMID: 24575090 PMCID: PMC3918933 DOI: 10.3389/fimmu.2014.00023] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 01/15/2014] [Indexed: 01/07/2023] Open
Abstract
The ability of dendritic cells (DCs) to stimulate and regulate T cells is critical to effective anti-tumor immunity. Therefore, it is important to fully recognize any inherent factors which may influence DC function under experimental conditions, especially in laboratory mice since they are used so heavily to model immune responses. The goals of this report are to 1) briefly summarize previous work revealing how DCs respond to various forms of physiological stress and 2) to present new data highlighting the potential for chronic mild cold stress inherent to mice housed at the required standard ambient temperatures to influence baseline DCs properties in naïve and tumor-bearing mice. As recent data from our group shows that CD8+ T cell function is significantly altered by chronic mild cold stress and since DC function is crucial for CD8+ T cell activation, we wondered whether housing temperature may also be influencing DC function. Here we report that there are several significant phenotypical and functional differences among DC subsets in naïve and tumor-bearing mice housed at either standard housing temperature or at a thermoneutral ambient temperature, which significantly reduces the extent of cold stress. The new data presented here strongly suggests that, by itself, the housing temperature of mice can affect fundamental properties and functions of DCs. Therefore differences in basal levels of stress due to housing should be taken into consideration when interpreting experiments designed to evaluate the impact of additional variables, including other stressors on DC function.
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Affiliation(s)
- Kathleen M Kokolus
- Department of Immunology, Roswell Park Cancer Institute , Buffalo, NY , USA
| | - Haley M Spangler
- Department of Immunology, Roswell Park Cancer Institute , Buffalo, NY , USA
| | | | - Matthew R Farren
- Department of Immunology, Roswell Park Cancer Institute , Buffalo, NY , USA
| | - Kelvin P Lee
- Department of Immunology, Roswell Park Cancer Institute , Buffalo, NY , USA
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Townsend KL, An D, Lynes MD, Huang TL, Zhang H, Goodyear LJ, Tseng YH. Increased mitochondrial activity in BMP7-treated brown adipocytes, due to increased CPT1- and CD36-mediated fatty acid uptake. Antioxid Redox Signal 2013; 19:243-57. [PMID: 22938691 PMCID: PMC3691916 DOI: 10.1089/ars.2012.4536] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
AIMS Brown adipose tissue dissipates chemical energy in the form of heat and regulates triglyceride and glucose metabolism in the body. Factors that regulate fatty acid uptake and oxidation in brown adipocytes have not yet been fully elucidated. Bone morphogenetic protein 7 (BMP7) is a growth factor capable of inducing brown fat mitochondrial biogenesis during differentiation from adipocyte progenitors. Administration of BMP7 to mice also results in increased energy expenditure. To determine if BMP7 is able to affect the mitochondrial activity of mature brown adipocytes, independent of the differentiation process, we delivered BMP7 to mature brown adipocytes and measured mitochondrial activity. RESULTS We found that BMP7 increased mitochondrial activity, including fatty acid oxidation and citrate synthase activity, without increasing the mitochondrial number. This was accompanied by an increase in fatty acid uptake and increased protein expression of CPT1 and CD36, which import fatty acids into the mitochondria and the cell, respectively. Importantly, inhibition of either CPT1 or CD36 resulted in a blunting of the mitochondrial activity of BMP7-treated cells. INNOVATION These findings uncover a novel pathway regulating mitochondrial activities in mature brown adipocytes by BMP7-mediated fatty acid uptake and oxidation. CONCLUSION In conclusion, BMP7 increases mitochondrial activity in mature brown adipocytes via increased fatty acid uptake and oxidation, a process that requires the fatty acid transporters CPT1 and CD36.
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Affiliation(s)
- Kristy L Townsend
- Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts 02215, USA
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Jun JC, Shin MK, Yao Q, Devera R, Fonti-Bevans S, Polotsky VY. Thermoneutrality modifies the impact of hypoxia on lipid metabolism. Am J Physiol Endocrinol Metab 2013; 304:E424-35. [PMID: 23249698 PMCID: PMC3566502 DOI: 10.1152/ajpendo.00515.2012] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hypoxia has been shown to rapidly increase triglycerides in mice by decreasing plasma lipoprotein clearance. However, the usual temperature of hypoxic exposure is below thermoneutrality for mice, which may increase thermogenesis and energy requirements, resulting in higher tissue lipid uptake. We hypothesize that decreased lipid clearance and ensuing hyperlipidemia are caused by hypoxic suppression of metabolism at cold temperatures and, therefore, would not occur at thermoneutrality. Twelve-week-old, male C57BL6/J mice were exposed to 6 h of 10% O₂ at the usual temperature (22°C) or thermoneutrality (30°C). Acclimation to 22°C increased lipid uptake in the heart, lungs, and brown adipose tissue, resulting in lower plasma triglyceride and cholesterol levels. At this temperature, hypoxia attenuated lipid uptake in most tissues, thereby raising plasma triglycerides and LDL cholesterol. Thermoneutrality decreased tissue lipid uptake, and hypoxia did not cause a further reduction in lipid uptake in any organs. Consequently, hypoxia at thermoneutrality did not affect plasma triglyceride levels. Unexpectedly, plasma HDL cholesterol increased. The effect of hypoxia on white adipose tissue lipolysis was also modified by temperature. Independent of temperature, hypoxia increased heart rate and glucose and decreased activity, body temperature, and glucose sensitivity. Our study underscores the importance of ambient temperature for hypoxia research, especially in studies of lipid metabolism.
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Affiliation(s)
- Jonathan C Jun
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA.
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Ippagunta S, Hadenfeldt TJ, Miner JL, Hargrave-Barnes KM. Dietary conjugated linoleic acid induces lipolysis in adipose tissue of coconut oil-fed mice but not soy oil-fed mice. Lipids 2011; 46:821-30. [PMID: 21643838 DOI: 10.1007/s11745-011-3574-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Accepted: 05/10/2011] [Indexed: 10/18/2022]
Abstract
Mice fed diets containing conjugated linoleic acid (CLA) are leaner than mice not fed CLA. This anti-obesity effect is amplified in mice fed coconut oil-containing or fat free diets, compared to soy oil diets. The present objective was to determine if CLA alters lipolysis in mice fed different base oils. Mice were fed diets containing soy oil (SO), coconut oil (CO), or fat free (FF) for 6 weeks, followed by 10 or 12 days of CLA or no CLA supplementation. Body fat, tissue weights, and ex vivo lipolysis were determined. Relative protein abundance and activation of perilipin, hormone sensitive lipase (HSL), adipose triglyceride lipase (ATGL), and adipose differentiation related protein (ADRP) were determined by western blotting. CLA feeding caused mice to have less (P < 0.05) body fat than non-CLA fed mice. This was enhanced in CO and FF-fed mice (CLA × oil source, P < 0.05). There was also a CLA × oil source interaction on lipolysis as CO + CLA and FF + CLA-fed mice had increased (P < 0.05) rates of lipolysis but SO + CLA-fed mice did not. However, after 12 days of CLA consumption, activated perilipin was increased (P < 0.05) only in SO + CLA-fed mice and total HSL and ATGL were decreased (P < 0.05) in CO + CLA-fed mice. Therefore, the enhanced CLA-induced body fat loss in CO and FF-fed mice appears to involve increased lipolysis but this effect may be decreasing by 12 days of CLA consumption.
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Affiliation(s)
- S Ippagunta
- Division of Animal and Nutritional Sciences, West Virginia University, Morgantown, WV 26506, 6108, USA
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