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Uppuganti S, Creecy A, Fernandes D, Garrett K, Donovan K, Ahmed R, Voziyan P, Rendina-Ruedy E, Nyman JS. Bone Fragility in High Fat Diet-induced Obesity is Partially Independent of Type 2 Diabetes in Mice. Calcif Tissue Int 2024; 115:298-314. [PMID: 39012489 PMCID: PMC11333511 DOI: 10.1007/s00223-024-01252-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Accepted: 06/27/2024] [Indexed: 07/17/2024]
Abstract
Obesity and type 2 diabetes (T2D) are risk factors for fragility fractures. It is unknown whether this elevated risk is due to a diet favoring obesity or the diabetes that often occurs with obesity. Therefore, we hypothesized that the fracture resistance of bone is lower in mice fed with a high fat diet (45% kcal; HFD) than in mice that fed on a similar, control diet (10% kcal; LFD), regardless of whether the mice developed overt T2D. Sixteen-week-old, male NON/ShiLtJ mice (resistant to T2D) and age-matched, male NONcNZO10/LtJ (prone to T2D) received a control LFD or HFD for 21 weeks. HFD increased the bodyweight to a greater extent in the ShiLtJ mice compared to the NZO10 mice, while blood glucose levels were significantly higher in NZO10 than in ShiLtJ mice. As such, the glycated hemoglobin A1c (HbA1c) levels exceeded 10% in NZO10 mice, but it remained below 6% in ShiLtJ mice. Diet did not affect HbA1c. HFD lowered trabecular number and bone volume fraction of the distal femur metaphysis (micro-computed tomography or μCT) in both strains. For the femur mid-diaphysis, HFD significantly reduced the yield moment (mechanical testing by three-point bending) in both strains but did not affect cross-sectional bone area, cortical thickness, nor cortical tissue mineral density (μCT). Furthermore, the effect of diet on yield moment was independent of the structural resistance of the femur mid-diaphysis suggesting a negative effect of HFD on characteristics of the bone matrix. However, neither Raman spectroscopy nor assays of advanced glycation end-products identified how HFD affected the matrix. HFD also lowered the resistance of cortical bone to crack growth in only the diabetic NZO10 mice (fracture toughness testing of other femur), while HFD reduced the ultimate force of the L6 vertebra in both strains (compression testing). In conclusion, the HFD-related decrease in bone strength can occur in mice resistant and prone to diabetes indicating that a diet high in fat deleteriously affects bone without necessarily causing hyperglycemia.
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Affiliation(s)
- Sasidhar Uppuganti
- Department of Orthopaedic Surgery, Vanderbilt University Medical Center, Medical Center East, South Tower, 1215 21st Ave. S., Suite 4200, Nashville, TN, 37232, USA
- Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, 2215B Garland Ave., Nashville, TN, 37212, USA
| | - Amy Creecy
- Department of Orthopaedic Surgery, Indiana University School of Medicine, 550 N. University Blvd, Indianapolis, IN, 46202, USA
| | - Daniel Fernandes
- Department of Biomedical Engineering, Vanderbilt University, 5824 Stevenson Center, Nashville, TN, 37232, USA
| | - Kate Garrett
- Department of Orthopaedic Surgery, Vanderbilt University Medical Center, Medical Center East, South Tower, 1215 21st Ave. S., Suite 4200, Nashville, TN, 37232, USA
| | - Kara Donovan
- Department of Biomedical Engineering, Vanderbilt University, 5824 Stevenson Center, Nashville, TN, 37232, USA
| | - Rafay Ahmed
- Department of Orthopaedic Surgery, Vanderbilt University Medical Center, Medical Center East, South Tower, 1215 21st Ave. S., Suite 4200, Nashville, TN, 37232, USA
- Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, 2215B Garland Ave., Nashville, TN, 37212, USA
| | - Paul Voziyan
- Department of Orthopaedic Surgery, Vanderbilt University Medical Center, Medical Center East, South Tower, 1215 21st Ave. S., Suite 4200, Nashville, TN, 37232, USA
- Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, 2215B Garland Ave., Nashville, TN, 37212, USA
| | - Elizabeth Rendina-Ruedy
- Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, 2215B Garland Ave., Nashville, TN, 37212, USA
- Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, 2215 Garland Ave., Nashville, TN, 37232, USA
| | - Jeffry S Nyman
- Department of Orthopaedic Surgery, Vanderbilt University Medical Center, Medical Center East, South Tower, 1215 21st Ave. S., Suite 4200, Nashville, TN, 37232, USA.
- Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, 2215B Garland Ave., Nashville, TN, 37212, USA.
- Department of Biomedical Engineering, Vanderbilt University, 5824 Stevenson Center, Nashville, TN, 37232, USA.
- United States Department of Veterans Affairs, Tennessee Valley Healthcare System, 1310 24th Ave. S., Nashville, TN, 37212, USA.
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Xm S, Cc L, C L, Yf L, L C, Yz Z, Sj Y. TLR4 inhibition ameliorated glucolipotoxicity-induced differentiation suppression in osteoblasts via RIAM regulation of NF-κB nuclear translocation. Mol Cell Endocrinol 2022; 543:111539. [PMID: 34929310 DOI: 10.1016/j.mce.2021.111539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 12/03/2021] [Accepted: 12/15/2021] [Indexed: 11/26/2022]
Abstract
TLR4 is a key innate immune signal that mediates glucolipid toxicity through yet unclear mechanisms. Here, TLR4 truncation ameliorated bone metabolism disorders in diabetic rats, and the underlying mechanisms were explored by proteomics. Our study showed that TLR4 truncation inhibited bone loss induced by diabetes in rats. In addition, a proteomic analysis screen exposed the differential proteins associated with immune reactivity and T cell activation (RIAM and Class II histocompatibility antigen, M β1 chain). Further cellular experiments showed that TLR4 mediated the inhibition of osteoblast differentiation induced by glucolipotoxicity and promoted an increase in the nuclear level of RIAM-NF-κB. Mechanistic studies showed that TLR4 mediated glucolipotoxicity induced damage in bone metabolism primarily by regulating RIAM-NF-κB interactions, which promoted RIAM-NF-κB nuclear translocation. In conclusion, we confirmed that TLR4 inhibition could delay bone metabolism disorders induced by glycolipid toxicity via RIAM regulation of NF-κB nuclear translocation.
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Affiliation(s)
- Shen Xm
- Department of Endocrinology, The First Affiliated Hospital of Fujian Medical University, 20 Cha Zhong Road, Fuzhou, Fujian, 350005, China; Diabetes Research Institute of Fujian Province, The First Affiliated Hospital of Fujian Medical University, 20 Cha Zhong Road, Fuzhou, Fujian, 350005, China; Metabolic Diseases Research Institute, The First Affiliated Hospital of Fujian Medical University, 20 Cha Zhong Road, Fuzhou, Fujian, 350005, China; Clinical Research Center for Metabolic Diseases of Fujian Province, The First Affiliated Hospital of Fujian Medical University, 20 Cha Zhong Road, Fuzhou, Fujian, 350005, China
| | - Li Cc
- Department of Endocrinology, The First Affiliated Hospital of Fujian Medical University, 20 Cha Zhong Road, Fuzhou, Fujian, 350005, China; Department of Cardiology, Affiliated Fuzhou First Hospital of Fujian Medical University, 190 Da Dao Road, Fuzhou, Fujian, 350009, China
| | - Lan C
- Department of Endocrinology, The First Affiliated Hospital of Fujian Medical University, 20 Cha Zhong Road, Fuzhou, Fujian, 350005, China
| | - Lin Yf
- Department of Endocrinology, The First Affiliated Hospital of Fujian Medical University, 20 Cha Zhong Road, Fuzhou, Fujian, 350005, China
| | - Cheng L
- Department of Endocrinology, The First Affiliated Hospital of Fujian Medical University, 20 Cha Zhong Road, Fuzhou, Fujian, 350005, China
| | - Zhang Yz
- Department of Endocrinology, The First Affiliated Hospital of Fujian Medical University, 20 Cha Zhong Road, Fuzhou, Fujian, 350005, China; Diabetes Research Institute of Fujian Province, The First Affiliated Hospital of Fujian Medical University, 20 Cha Zhong Road, Fuzhou, Fujian, 350005, China; Metabolic Diseases Research Institute, The First Affiliated Hospital of Fujian Medical University, 20 Cha Zhong Road, Fuzhou, Fujian, 350005, China; Clinical Research Center for Metabolic Diseases of Fujian Province, The First Affiliated Hospital of Fujian Medical University, 20 Cha Zhong Road, Fuzhou, Fujian, 350005, China
| | - Yan Sj
- Department of Endocrinology, The First Affiliated Hospital of Fujian Medical University, 20 Cha Zhong Road, Fuzhou, Fujian, 350005, China; Diabetes Research Institute of Fujian Province, The First Affiliated Hospital of Fujian Medical University, 20 Cha Zhong Road, Fuzhou, Fujian, 350005, China; Metabolic Diseases Research Institute, The First Affiliated Hospital of Fujian Medical University, 20 Cha Zhong Road, Fuzhou, Fujian, 350005, China; Clinical Research Center for Metabolic Diseases of Fujian Province, The First Affiliated Hospital of Fujian Medical University, 20 Cha Zhong Road, Fuzhou, Fujian, 350005, China.
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Toll-like Receptor 4, Osteoblasts and Leukemogenesis; the Lesson from Acute Myeloid Leukemia. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27030735. [PMID: 35163998 PMCID: PMC8838156 DOI: 10.3390/molecules27030735] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 01/13/2022] [Accepted: 01/19/2022] [Indexed: 12/29/2022]
Abstract
Toll-like receptor 4 (TLR4) is a pattern-recognizing receptor that can bind exogenous and endogenous ligands. It is expressed by acute myeloid leukemia (AML) cells, several bone marrow stromal cells, and nonleukemic cells involved in inflammation. TLR4 can bind a wide range of endogenous ligands that are present in the bone marrow microenvironment. Furthermore, the TLR4-expressing nonleukemic bone marrow cells include various mesenchymal cells, endothelial cells, differentiated myeloid cells, and inflammatory/immunocompetent cells. Osteoblasts are important stem cell supporting cells localized to the stem cell niches, and they support the proliferation and survival of primary AML cells. These supporting effects are mediated by the bidirectional crosstalk between AML cells and supportive osteoblasts through the local cytokine network. Finally, TLR4 is also important for the defense against complicating infections in neutropenic patients, and it seems to be involved in the regulation of inflammatory and immunological reactions in patients treated with allogeneic stem cell transplantation. Thus, TLR4 has direct effects on primary AML cells, and it has indirect effects on the leukemic cells through modulation of their supporting neighboring bone marrow stromal cells (i.e., modulation of stem cell niches, regulation of angiogenesis). Furthermore, in allotransplant recipients TLR4 can modulate inflammatory and potentially antileukemic immune reactivity. The use of TLR4 targeting as an antileukemic treatment will therefore depend both on the biology of the AML cells, the biological context of the AML cells, aging effects reflected both in the AML and the stromal cells and the additional antileukemic treatment combined with HSP90 inhibition.
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Rendina-Ruedy E, Smith BJ. Common Dietary Modifications in Preclinical Models to Study Skeletal Health. Front Endocrinol (Lausanne) 2022; 13:932343. [PMID: 35909523 PMCID: PMC9329513 DOI: 10.3389/fendo.2022.932343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 05/27/2022] [Indexed: 12/03/2022] Open
Abstract
Bone is a highly dynamic tissue that undergoes continuous remodeling by bone resorbing osteoclasts and bone forming osteoblasts, a process regulated in large part by osteocytes. Dysregulation of these coupled catabolic and anabolic processes as in the case of menopause, type 2 diabetes mellitus, anorexia nervosa, and chronic kidney disease is known to increase fracture risk. Recent advances in the field of bone cell metabolism and bioenergetics have revealed that maintenance of the skeleton places a high energy demand on these cells involved in bone remodeling. These new insights highlight the reason that bone tissue is the beneficiary of a substantial proportion of cardiac output and post-prandial chylomicron remnants and requires a rich supply of nutrients. Studies designed for the specific purpose of investigating the impact of dietary modifications on bone homeostasis or that alter diet composition and food intake to produce the model can be found throughout the literature; however, confounding dietary factors are often overlooked in some of the preclinical models. This review will examine some of the common pre-clinical models used to study skeletal biology and its pathologies and the subsequent impact of various dietary factors on these model systems. Furthermore, the review will include how inadvertent effects of some of these dietary components can influence bone cell function and study outcomes.
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Affiliation(s)
- Elizabeth Rendina-Ruedy
- Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN, United States
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, United States
- *Correspondence: Elizabeth Rendina-Ruedy,
| | - Brenda J. Smith
- Department of Obstetrics and Gynecology, Indiana University School of Medicine, Indianapolis, IN, United States
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, United States
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Supplier-origin mouse microbiomes significantly influence locomotor and anxiety-related behavior, body morphology, and metabolism. Commun Biol 2021; 4:716. [PMID: 34112927 PMCID: PMC8192786 DOI: 10.1038/s42003-021-02249-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 05/20/2021] [Indexed: 12/26/2022] Open
Abstract
The mouse is the most commonly used model species in biomedical research. Just as human physical and mental health are influenced by the commensal gut bacteria, mouse models of disease are influenced by the fecal microbiome (FM). The source of mice represents one of the strongest influences on the FM and can influence the phenotype of disease models. The FM influences behavior in mice leading to the hypothesis that mice of the same genetic background from different vendors, will have different behavioral phenotypes. To test this hypothesis, colonies of CD-1 mice, rederived via embryo transfer into surrogate dams from four different suppliers, were subjected to phenotyping assays assessing behavior and physiological parameters. Significant differences in behavior, growth rate, metabolism, and hematological parameters were observed. Collectively, these findings show the profound influence of supplier-origin FMs on host behavior and physiology in healthy, genetically similar, wild-type mice maintained in identical environments.
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Liang B, Shen X, Lan C, Lin Y, Li C, Zhong S, Yan S. Glycolipid toxicity induces osteogenic dysfunction via the TLR4/S100B pathway. Int Immunopharmacol 2021; 97:107792. [PMID: 34051593 DOI: 10.1016/j.intimp.2021.107792] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 05/11/2021] [Accepted: 05/16/2021] [Indexed: 01/22/2023]
Abstract
Diabetes can cause bone metabolism disorders and osteoporosis. The occurrence of both diabetes mellitus and osteoporosis increases the disability and mortality of elderly individuals due to pathological fracture. Abnormal metabolism of nutrientsis considered to be one of the important mechanisms of diabetes mellitus-induced osteoporosis. This study preliminarily explored the roles of TLR4 (Toll-like receptor 4) and S100B in osteogenic dysfunction induced by glycolipid toxicity. In this study, a diabetic rat model and TLR4-knockdown diabetic rat model were used in vivo. MC3T3-E1 cells in a high glucose and palmitic acid environment were used as glycolipid toxicity cell models in vitro. We investigated the effects of TLR4 and S100B on osteogenesis by overexpression or inhibition of TLR4 and S100B in vitro. We found that when TLR4 or S100B was inhibited, ALP and OCN were significantly up-regulated and p-ERK was significantly down regulated in the glycolipid model. These results suggest that TLR4/S100B may play a role in reducing glycolipid toxicity by regulating ERK phosphorylation.
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Affiliation(s)
- Bo Liang
- Department of Endocrinology, M.D. Candidate, The First Affiliated Hospital of Fujian Medical University, China; Department of Endocrinology, The Second Affiliated Hospital of Fujian Medical University, China
| | - Ximei Shen
- Department of Endocrinology, M.D. Candidate, The First Affiliated Hospital of Fujian Medical University, China; Diabetes Research Institute of Fujian Province, Fuzhou, Fujian, China
| | - Chao Lan
- Department of Endocrinology, M.D. Candidate, The First Affiliated Hospital of Fujian Medical University, China
| | - Youfen Lin
- Department of Endocrinology, M.D. Candidate, The First Affiliated Hospital of Fujian Medical University, China
| | - Chuanchuan Li
- Department of Endocrinology, M.D. Candidate, The First Affiliated Hospital of Fujian Medical University, China
| | - Shuai Zhong
- Department of Endocrinology, M.D. Candidate, The First Affiliated Hospital of Fujian Medical University, China
| | - Sunjie Yan
- Department of Endocrinology, M.D. Candidate, The First Affiliated Hospital of Fujian Medical University, China; Diabetes Research Institute of Fujian Province, Fuzhou, Fujian, China.
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Sherk VD, Heveran CM, Foright RM, Johnson GC, Presby DM, Ferguson VL, MacLean PS. Sex differences in the effect of diet, obesity, and exercise on bone quality and fracture toughness. Bone 2021; 145:115840. [PMID: 33418101 PMCID: PMC11313485 DOI: 10.1016/j.bone.2021.115840] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 12/03/2020] [Accepted: 12/30/2020] [Indexed: 11/23/2022]
Abstract
Bone fragility and obesity are both diseases that are multifactorial in etiology and pathology. The contributing role of high fat diet (HFD) versus energy overconsumption on bone health is controversial. Exercise is often prescribed for improving bone health, but it is unclear whether HFD or overconsumption influences skeletal adaptations to exercise. Female and male Wistar rats were fed HFD or low fat diet (LFD) for 10 weeks, starting at 8 weeks of age. Within HFD, rats were labeled Obesity-Resistant (OR) or Obesity-Prone (OP) based on weight and fat gain. Within each diet and phenotype group, rats were randomized to treadmill exercise or sedentary control (SED) for the final 4 weeks. Femurs were assessed for fracture toughness. Cortical lamellar and nonlamellar bone microscale material behavior and chemistry were assessed using nanoindentation and Raman spectroscopy. Female bones had higher fracture toughness and mineral: matrix ratio than male bones. Diet and energy overconsumption affected bone characteristics in a sex-dependent manner, where the divergence between OP and OR in response to HFD occurred more rapidly in males. Diet composition, in general, had a stronger effect on bone quality than overconsumption. HFD dramatically decreased bone size and lamellar mineral:matrix compared to LFD. Effects of short-term exercise training on microscale tissue properties were generally more robust with LFD. Exercise enhanced the contrast between lamellar and nonlamellar bone for nanoindentation modulus but decreased this contrast for plastic work. Our data demonstrate the complexities in the relationship between diet and obesity and highlight the importance of addressing both aspects when characterizing bone quality and fracture resistance.
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Affiliation(s)
- Vanessa D Sherk
- Department of Orthopedics, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America.
| | - Chelsea M Heveran
- Department of Mechanical & Industrial Engineering, Montana State University, Bozeman, MT, United States of America
| | - Rebecca M Foright
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America
| | - Ginger C Johnson
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America
| | - David M Presby
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America
| | - Virginia L Ferguson
- Department of Orthopedics, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America; Department of Mechanical Engineering, University of Colorado, Boulder, CO; (5)BioFrontiers Institute, University of Colorado, Boulder, CO, United States of America
| | - Paul S MacLean
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America
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BIOMECHANICAL PROPERTIES AND MACROELEMENT ELEMENT COMPOSITION OF LONG TUBULAR BONE OF RATS UNDER EXPERIMENTAL HYPERGLYCAEMIA. WORLD OF MEDICINE AND BIOLOGY 2021. [DOI: 10.26724/2079-8334-2021-2-76-232-238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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9
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Use of in vitro bone models to screen for altered bone metabolism, osteopathies, and fracture healing: challenges of complex models. Arch Toxicol 2020; 94:3937-3958. [PMID: 32910238 PMCID: PMC7655582 DOI: 10.1007/s00204-020-02906-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 09/03/2020] [Indexed: 02/06/2023]
Abstract
Approx. every third hospitalized patient in Europe suffers from musculoskeletal injuries or diseases. Up to 20% of these patients need costly surgical revisions after delayed or impaired fracture healing. Reasons for this are the severity of the trauma, individual factors, e.g, the patients’ age, individual lifestyle, chronic diseases, medication, and, over 70 diseases that negatively affect the bone quality. To investigate the various disease constellations and/or develop new treatment strategies, many in vivo, ex vivo, and in vitro models can be applied. Analyzing these various models more closely, it is obvious that many of them have limits and/or restrictions. Undoubtedly, in vivo models most completely represent the biological situation. Besides possible species-specific differences, ethical concerns may question the use of in vivo models especially for large screening approaches. Challenging whether ex vivo or in vitro bone models can be used as an adequate replacement for such screenings, we here summarize the advantages and challenges of frequently used ex vivo and in vitro bone models to study disturbed bone metabolism and fracture healing. Using own examples, we discuss the common challenge of cell-specific normalization of data obtained from more complex in vitro models as one example of the analytical limits which lower the full potential of these complex model systems.
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Rossetti CL, Oliveira Costa HM, Barthem CS, da Silva MH, Carvalho DP, da‐Silva WS. Sexual dimorphism of liver endoplasmic reticulum stress susceptibility in prepubertal rats and the effect of sex steroid supplementation. Exp Physiol 2019; 104:677-690. [DOI: 10.1113/ep087518] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 02/27/2019] [Indexed: 12/13/2022]
Affiliation(s)
- Camila Lüdke Rossetti
- Laboratório de Adaptações Metabólicas, Programa de Bioquímica e Biofísica Celular, Instituto de Bioquímica Médica Leopoldo de MeisUniversidade Federal do Rio de Janeiro, Cidade Universitária Rio de Janeiro Rio de Janeiro 21941‐902 Brazil
- Laboratório de Fisiologia Endócrina Doris Rosenthal, Instituto de Biofísica Carlos Chagas FilhoUniversidade Federal do Rio de Janeiro, Cidade Universitária, Rio de Janeiro Rio de Janeiro 21949‐900 Brazil
| | - Hellen Marianne Oliveira Costa
- Laboratório de Adaptações Metabólicas, Programa de Bioquímica e Biofísica Celular, Instituto de Bioquímica Médica Leopoldo de MeisUniversidade Federal do Rio de Janeiro, Cidade Universitária Rio de Janeiro Rio de Janeiro 21941‐902 Brazil
| | - Clarissa Souza Barthem
- Laboratório de Adaptações Metabólicas, Programa de Bioquímica e Biofísica Celular, Instituto de Bioquímica Médica Leopoldo de MeisUniversidade Federal do Rio de Janeiro, Cidade Universitária Rio de Janeiro Rio de Janeiro 21941‐902 Brazil
| | - Michele Hinerasky da Silva
- Laboratório de Adaptações Metabólicas, Programa de Bioquímica e Biofísica Celular, Instituto de Bioquímica Médica Leopoldo de MeisUniversidade Federal do Rio de Janeiro, Cidade Universitária Rio de Janeiro Rio de Janeiro 21941‐902 Brazil
| | - Denise P. Carvalho
- Laboratório de Fisiologia Endócrina Doris Rosenthal, Instituto de Biofísica Carlos Chagas FilhoUniversidade Federal do Rio de Janeiro, Cidade Universitária, Rio de Janeiro Rio de Janeiro 21949‐900 Brazil
| | - Wagner Seixas da‐Silva
- Laboratório de Adaptações Metabólicas, Programa de Bioquímica e Biofísica Celular, Instituto de Bioquímica Médica Leopoldo de MeisUniversidade Federal do Rio de Janeiro, Cidade Universitária Rio de Janeiro Rio de Janeiro 21941‐902 Brazil
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Zheng L, Shen X, Ye J, Xie Y, Yan S. Metformin alleviates hyperglycemia-induced apoptosis and differentiation suppression in osteoblasts through inhibiting the TLR4 signaling pathway. Life Sci 2018; 216:29-38. [PMID: 30414431 DOI: 10.1016/j.lfs.2018.11.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 10/27/2018] [Accepted: 11/05/2018] [Indexed: 02/07/2023]
Abstract
AIMS Metformin was found to protect against hyperglycemia-induced injury in osteoblasts, but the cellular mechanisms involved remain unclear. Therefore, the aim of this study was to determine the effect of metformin on hyperglycemia-induced apoptosis and differentiation suppression in osteoblasts and to explore its relationships with the TLR4 signaling pathway. MAIN METHODS A mouse osteoblast cell line, MC3T3-E1, and a diabetic rat model were used to survey the protective effects of metformin on hyperglycemia-induced injury. TLR4 expression was altered using small interfering (si)RNA and lentivirus-mediated TLR4 overexpression. LPS was used as a specific TLR4 activator, and CLI-095 was used as a TLR4 inhibitor. KEY FINDINGS Metformin improved osteoblast differentiation, reduced apoptosis in hyperglycemic osteoblasts, and inhibited TLR4, MyD88 and NF-κB expression in a dose-dependent manner. Down-regulating the expression or inhibiting the activity of TLR4 enhanced these protective effects of metformin on osteoblast differentiation, cell viability and cell apoptosis in hyperglycemic conditions, whereas up-regulating the expression or activating the activity of TLR4 had the opposite effects. Activating NF-κB suppressed the protective effects of metformin, while inhibiting NF-κB activity had the opposite effects. Metformin increased ALP and OCN secretion, enhanced BMP-2 expression, improved bone mineral density (BMD), and decreased TLR4, MyD88 and NF-κB levels in the femur tissues of diabetic rats. SIGNIFICANCE Taken together our experimentation support the hypothesis that metformin may alleviate hyperglycemia-induced apoptosis and differentiation suppression in osteoblasts by inhibiting the TLR4/MyD88/NF-κB signaling pathway.
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Affiliation(s)
- Lifeng Zheng
- Department of Orthopedics, the First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, Fujian, China
| | - Ximei Shen
- Department of Endocrinology, the First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, Fujian, China; Diabetes Research Institute of Fujian Province, Fuzhou 350005, Fujian, China
| | - Junjian Ye
- Department of Orthopedics, the First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, Fujian, China
| | - Yun Xie
- Department of Orthopedics, the First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, Fujian, China
| | - Sunjie Yan
- Department of Endocrinology, the First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, Fujian, China; Diabetes Research Institute of Fujian Province, Fuzhou 350005, Fujian, China.
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Alonso-Pérez A, Franco-Trepat E, Guillán-Fresco M, Jorge-Mora A, López V, Pino J, Gualillo O, Gómez R. Role of Toll-Like Receptor 4 on Osteoblast Metabolism and Function. Front Physiol 2018; 9:504. [PMID: 29867550 PMCID: PMC5952219 DOI: 10.3389/fphys.2018.00504] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 04/18/2018] [Indexed: 01/09/2023] Open
Abstract
Inflammation is a process whose main function is to fight against invading pathogens or foreign agents. Nonetheless, it is widely accepted that inflammation takes part in multiple processes in a physiological or pathophysiological context. Among these processes the inflammation has been closely related to bone metabolism. It is well-known that in systemic inflammatory diseases such as rheumatoid arthritis the inflammatory environment contributes to the reduction of the bone mineral density. This has been further evidenced in different animals models of osteoporosis where the deletion of key inflammatory molecules dramatically reduced the bone loss. On the contrary, it is also well-known that certain degree of inflammation is required to allow bone fractures healing. In fact, excessive use of anti-inflammatory drugs inhibits bone fracture consolidation. The innate immune responses (IIRs) contribute to the development and maintenance of the inflammation. These responses have been observed in cells of the musculoskeletal system. Chondrocytes and osteoblasts are equipped with the molecular repertoire necessary to setting up these IIR, including the expression of several toll-like receptors. Specifically, toll-like receptor 4 (TLR4) activation in mesenchymal stem cells, osteoblasts, and osteocytes has been involved in catabolic and anabolic process. Accordingly, in this review we have summarized the current knowledge about the physiology of TLR4, including its signaling, and its endogenous agonists. In addition we have focused on its role on osteoblast metabolism and function.
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Affiliation(s)
- Ana Alonso-Pérez
- Musculoskeletal Pathology Group, Laboratory 18, Institute IDIS, Servicio Galego de Saúde, Santiago de Compostela, Spain
| | - Eloi Franco-Trepat
- Musculoskeletal Pathology Group, Laboratory 18, Institute IDIS, Servicio Galego de Saúde, Santiago de Compostela, Spain
| | - María Guillán-Fresco
- Musculoskeletal Pathology Group, Laboratory 18, Institute IDIS, Servicio Galego de Saúde, Santiago de Compostela, Spain
| | - Alberto Jorge-Mora
- Musculoskeletal Pathology Group, Laboratory 18, Institute IDIS, Servicio Galego de Saúde, Santiago de Compostela, Spain
- Division of Traumatology, Santiago University Clinical Hospital, Santiago de Compostela, Spain
| | - Verónica López
- NEIRID LAB, Laboratory 9, Institute IDIS, Servicio Galego de Saúde, Santiago de Compostela, Spain
| | - Jesús Pino
- Division of Traumatology, Santiago University Clinical Hospital, Santiago de Compostela, Spain
- NEIRID LAB, Laboratory 9, Institute IDIS, Servicio Galego de Saúde, Santiago de Compostela, Spain
| | - Oreste Gualillo
- NEIRID LAB, Laboratory 9, Institute IDIS, Servicio Galego de Saúde, Santiago de Compostela, Spain
| | - Rodolfo Gómez
- Musculoskeletal Pathology Group, Laboratory 18, Institute IDIS, Servicio Galego de Saúde, Santiago de Compostela, Spain
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Yamanaka JS, Yanagihara GR, Carlos BL, Ramos J, Brancaleon BB, Macedo AP, Issa JPM, Shimano AC. A high-fat diet can affect bone healing in growing rats. J Bone Miner Metab 2018; 36:255-263. [PMID: 28516218 DOI: 10.1007/s00774-017-0837-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 03/24/2017] [Indexed: 12/11/2022]
Abstract
A high-fat diet (HFD) can have a negative effect on bone quality in young and old people. Although bone healing in children is normally efficient, there is no evidence that children who have a diet rich in fat have compromised bone fracture regeneration compared with children with recommended dietary fat levels. The purpose of the present study was to evaluate the effects of an HFD on bone healing in growing female rats. Twenty-six postweaning female Wistar rats were divided into two groups (13 animals per group): a standard diet (SD) group and an HFD (with 60% of energy from fat) group. The rats received the assigned diets for 5 weeks, and in the third week they were submitted to an osteotomy procedure of the left tibia. Body mass and feed intake were recorded during the experiment. One day before euthanasia, an insulin tolerance test was performed. After euthanasia, the tibiae were removed and analyzed by densitometry, mechanical testing, histomorphometry, stereology and immunohistochemistry. An HFD caused an adaptive response to maintain energetic balance by decreasing feed intake and causing insulin insensitivity. There was no change in bone mineral density, collagen amount and immunostaining for bone formation, but maximal load and stiffness were decreased in the HFD group. In addition, bone volume had a tendency to be higher in the SD group than in the HFD group. Compared with rats receiving an SD, growing rats receiving an HFD for 5 weeks had similar bone mineral density but altered mechanical properties at the osteotomy defect site.
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Affiliation(s)
- Jéssica Suzuki Yamanaka
- Departamento de Biomecânica, Medicina e Reabilitação do Aparelho Locomotor, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Rua Pedreira de Freitas, s/n, 14049-900, Ribeirão Preto, São Paulo, Brazil
| | - Gabriela Rezende Yanagihara
- Departamento de Biomecânica, Medicina e Reabilitação do Aparelho Locomotor, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Rua Pedreira de Freitas, s/n, 14049-900, Ribeirão Preto, São Paulo, Brazil
| | - Bruna Leonel Carlos
- Departamento de Biomecânica, Medicina e Reabilitação do Aparelho Locomotor, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Rua Pedreira de Freitas, s/n, 14049-900, Ribeirão Preto, São Paulo, Brazil
| | - Júnia Ramos
- Departamento de Morfologia, Fisiologia e Patologia Básica, Faculdade de Odontologia de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Brígida Batista Brancaleon
- Departamento de Biomecânica, Medicina e Reabilitação do Aparelho Locomotor, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Rua Pedreira de Freitas, s/n, 14049-900, Ribeirão Preto, São Paulo, Brazil
| | - Ana Paula Macedo
- Departamento de Materiais Dentários e Próteses, Faculdade de Odontologia de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - João Paulo Mardegan Issa
- Departamento de Biomecânica, Medicina e Reabilitação do Aparelho Locomotor, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Rua Pedreira de Freitas, s/n, 14049-900, Ribeirão Preto, São Paulo, Brazil
- Departamento de Morfologia, Fisiologia e Patologia Básica, Faculdade de Odontologia de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Antônio Carlos Shimano
- Departamento de Biomecânica, Medicina e Reabilitação do Aparelho Locomotor, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Rua Pedreira de Freitas, s/n, 14049-900, Ribeirão Preto, São Paulo, Brazil.
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Li X, Liu N, Wang Y, Liu J, Shi H, Qu Z, Du T, Guo B, Gu B. Brain and muscle aryl hydrocarbon receptor nuclear translocator-like protein-1 cooperates with glycogen synthase kinase-3β to regulate osteogenesis of bone-marrow mesenchymal stem cells in type 2 diabetes. Mol Cell Endocrinol 2017; 440:93-105. [PMID: 27717746 DOI: 10.1016/j.mce.2016.10.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 10/02/2016] [Accepted: 10/03/2016] [Indexed: 02/08/2023]
Abstract
Type 2 diabetes mellitus (T2DM) is associated with inhibited osteogenesis of bone marrow mesenchymal stem cells (BMSCs). Brain and muscle ARNT-like protein 1 (BMAL1) has been linked to the T2DM-related bone remodeling, however, the specific mechanism is still unclear. Herein, we aimed to determine the role of BMAL1 in T2DM-induced suppression of BMSCs osteogenesis. Inhibited osteogenesis and BMAL1 expression were showed in diabetic BMSCs. And while β-catenin and T cell factor (TCF) expression were decreased, the glycogen synthase kinase-3β (GSK-3β) and nemo-like kinase (NLK) expression were increased in diabetic BMSCs. Moreover, over-expression of BMAL1 led to recovered osteogenesis ability and activation of Wnt/β-catenin pathway, which was partially due to inhibition of GSK-3β caused by over-expression of BMAL1. Taken together, our findings provide new insights into the role of BMAL1 in T2DM-induced suppression of BMSCs osteogenesis. Over-expressed BMAL1 could recover BMSCs osteogenesis in T2DM partially by decreasing GSK-3β expression to activate Wnt/β-catenin pathway. BMAL1 may have a potential use in repairing diabetic bone metabolic disorders.
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Affiliation(s)
- Xiaoguang Li
- Institution of Stomatology, The General Hospital of Chinese PLA, Beijing, China.
| | - Na Liu
- Institution of Stomatology, The General Hospital of Chinese PLA, Beijing, China.
| | - Yizhu Wang
- Institution of Stomatology, The General Hospital of Chinese PLA, Beijing, China.
| | - Jinglong Liu
- Institution of Stomatology, The General Hospital of Chinese PLA, Beijing, China.
| | - Haigang Shi
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, China.
| | - Zhenzhen Qu
- Department of Stomatology, Beijing Xinhua Hospital, Beijing, China.
| | - Tingting Du
- Institution of Stomatology, The General Hospital of Chinese PLA, Beijing, China.
| | - Bin Guo
- Institution of Stomatology, The General Hospital of Chinese PLA, Beijing, China.
| | - Bin Gu
- Institution of Stomatology, The General Hospital of Chinese PLA, Beijing, China.
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Rezende Yanagihara G, Carminati Shimano R, Atsuko Tida J, Suzuki Yamanaka J, Yasuyo Fukada S, Mardegan Issa JP, Shimano AC, Tavares JM. Influence of High-Fat Diet on Bone Tissue: An Experimental Study in Growing Rats. J Nutr Health Aging 2017; 21:1337-1343. [PMID: 29188898 DOI: 10.1007/s12603-017-0871-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND The relationship between obesity and bone tissue remains contradictory, especially when the effect of high-fat diet is assessed in experimental models. The aim of this study was to evaluate the effects of high-fat diet on bone metabolism of growing rats. METHODS Twenty weaned female Wistar rats were equally divided into two groups: SD (standard diet) and HFD (high-fat diet with 60 % of energy as fat). After five weeks of the two diets, the rats were euthanized, and the liver, blood and bones extracted. The liver was analysed for malondialdehyde (MDA) and reduced glutathione (GSH) concentrations. Blood was analysed by the ELISA method for osteoprotegerin (OPG) and tumour necrosis factor ligand superfamily member 11 (TNFSF11/RANKL). The bone tissue was analysed by dual-energy X-ray absorptiometry (DXA), mechanical tests, computed microtomography, histological quantitative analysis and scanning electron microscopy. The gene expressions of PPAR-γ Runx-2, RANKL and Cathepsin-K were also evaluated. RESULTS HFD caused an increase in the MDA concentration, indicating oxidative stress. It also increased the expression of PPAR-γ, which is the gene that is related to adipocyte differentiation. There was an increase in BMD of the tibia of animals fed with the HFD, but other microstructural and mechanical properties were maintained unaltered. In addition, there were no changes in the gene expressions related to the differentiation of osteoblasts and osteoclasts, as well as no changes to the biochemical markers of bone formation and bone resorption. CONCLUSION Liver and gene parameters are changed in response to the HFD. However, although there was an increase in BMD, the microstructure and function of the bone did not change after a 5-week HFD.
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Affiliation(s)
- G Rezende Yanagihara
- Prof. João Manuel R. S. Tavares, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal, , Phone: +351 22 5081487, Fax: +351 22 5081445, url: www.fe.up.pt/~tavares
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16
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Rendina-Ruedy E, Graef J, Lightfoot S, Ritchey J, Clarke S, Lucas E, Smith B. Impaired glucose tolerance attenuates bone accrual by promoting the maturation of osteoblasts: Role of Beclin1-mediated autophagy. Bone Rep 2016; 5:199-207. [PMID: 28580387 PMCID: PMC5440954 DOI: 10.1016/j.bonr.2016.08.001] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 08/07/2016] [Indexed: 11/22/2022] Open
Abstract
Patients with type 2 diabetes mellitus (T2DM) experience a 1.5-3.5 fold increase in fracture risk, but the mechanisms responsible for these alterations in bone biomechanical properties remain elusive. Macroautophagy, often referred to as autophagy, is regulated by signaling downstream of the insulin receptor. Metabolic changes associated with the progression of glucose intolerance have been shown to alter autophagy in various tissues, but limited information is available in relation to bone cells. The aim of this study was to (a) investigate whether autophagy is altered in bone tissue during impaired glucose tolerance, and (b) determine how autophagy impacts osteoblast differentiation, activity, and maturation. Four-week-old, male C57BL/6 mice were fed a control (Con) or high fat (HF) diet for 2, 8, or 16 wks. Mice on the HF diet demonstrated elevated fasting blood glucose and impaired glucose tolerance. Reduced trabecular bone in the femoral neck was evident in the mice on the HF diet by 8 wks compared to Con mice. Histological evaluation of the tibia suggested that the high fat diet promoted terminal differentiation of the osteoblast to an osteocyte. This shift of the osteoblasts towards a non-mineralizing, osteocyte phenotype appears to be coordinated by Beclin1-mediated autophagy. Consistent with these changes in the osteoblast in vivo, the induction of autophagy was able to direct MC3T3-E1 cells towards a more mature osteoblast phenotype. Although these data are somewhat observational, further investigation is warranted to determine if Beclin1-mediated autophagy is essential for the terminal differentiation of the osteoblasts and whether autophagy is having a protective or deleterious effect on bone in T2DM.
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Key Words
- AGEs, advanced glycation end products
- AIN, American Institute of Nutrition
- AMPK, adenosine monophosphate-activated protein kinase
- Ambra1, vacuole sorting protein (Vps34/15), activating molecule in Beclin-1 regulator autophagy
- Atg, autophagy-related proteins
- BafA1, bafilomycinA1
- Beclin1, Bcl-2-interacting myosin-like coiled-coil protein
- FIP200, focal adhesion
- Hyperglycemia
- IR, insulin receptor
- Insulin
- LC3, microtubule associated light chain
- Macroautophagy
- Osteocyte
- PE, phosphatidylethanolamine
- ROCK1, rho kinase 1
- Rap, rapamycin
- T2DM, type 2 diabetes mellitus
- ULK1/2, unc-like kinase
- UVRAG, ultraviolet radiation resistance-associated gene
- mTORC1, mammalian or mechanistic target of rapamycin complex
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Affiliation(s)
- E. Rendina-Ruedy
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, United States
| | - J.L. Graef
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, United States
| | - S.A. Lightfoot
- Center for Cancer Prevention and Drug Development, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - J.W. Ritchey
- Department of Veterinary Pathobiology, Oklahoma State University, Stillwater, OK, United States
| | - S.L. Clarke
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, United States
| | - E.A. Lucas
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, United States
| | - B.J. Smith
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, United States
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Rendina-Ruedy E, Smith BJ. Methodological considerations when studying the skeletal response to glucose intolerance using the diet-induced obesity model. BONEKEY REPORTS 2016; 5:845. [PMID: 27818742 PMCID: PMC5081001 DOI: 10.1038/bonekey.2016.71] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 08/24/2016] [Indexed: 01/22/2023]
Abstract
The prevalence of obesity and type 2 diabetes mellitus (T2DM) continues to rise, and as a result, research aimed at understanding the molecular basis for the co-morbidities has become an area of much scientific interest. Among the more recently recognized chronic complications of T2DM is the increased risk of fracture, especially hip fracture, that has been reported independent of bone mineral density (BMD). A widely used animal model to study how the development and progression of impaired glucose tolerance affect the skeleton has been the diet-induce obesity (DIO) model. As the name implies, this model employs the use of a version of high-fat diets to induce obesity and the subsequent metabolic perturbations that occur with T2DM. Although the model offers a number of advantages, the literature reveals some inconsistent results. Upon further review, discrepancies in the choice of the experimental high-fat diets and the control diets have become a point of major concern. The variability between diets and study design has made it difficult to compare data and results across studies. Therefore, this review aims to provide guidelines that should be employed when designing studies using DIO models of T2DM.
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Affiliation(s)
| | - Brenda J Smith
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, USA
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Jackson EE, Rendina-Ruedy E, Smith BJ, Lacombe VA. Loss of Toll-Like Receptor 4 Function Partially Protects against Peripheral and Cardiac Glucose Metabolic Derangements During a Long-Term High-Fat Diet. PLoS One 2015; 10:e0142077. [PMID: 26539824 PMCID: PMC4634760 DOI: 10.1371/journal.pone.0142077] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 10/16/2015] [Indexed: 02/06/2023] Open
Abstract
Diabetes is a chronic inflammatory disease that carries a high risk of cardiovascular disease. However, the pathophysiological link between these disorders is not well known. We hypothesize that TLR4 signaling mediates high fat diet (HFD)-induced peripheral and cardiac glucose metabolic derangements. Mice with a loss-of-function mutation in TLR4 (C3H/HeJ) and age-matched control (C57BL/6) mice were fed either a high-fat diet or normal diet for 16 weeks. Glucose tolerance and plasma insulin were measured. Protein expression of glucose transporters (GLUT), AKT (phosphorylated and total), and proinflammatory cytokines (IL-6, TNF-α and SOCS-3) were quantified in the heart using Western Blotting. Both groups fed a long-term HFD had increased body weight, blood glucose and insulin levels, as well as impaired glucose tolerance compared to mice fed a normal diet. TLR4-mutant mice were partially protected against long-term HFD-induced insulin resistance. In control mice, feeding a HFD decreased cardiac crude membrane GLUT4 protein content, which was partially rescued in TLR4-mutant mice. TLR4-mutant mice fed a HFD also had increased expression of GLUT8, a novel isoform, compared to mice fed a normal diet. GLUT8 content was positively correlated with SOCS-3 and IL-6 expression in the heart. No significant differences in cytokine expression were observed between groups, suggesting a lack of inflammation in the heart following a HFD. Loss of TLR4 function partially restored a healthy metabolic phenotype, suggesting that TLR4 signaling is a key mechanism in HFD-induced peripheral and cardiac insulin resistance. Our data further suggest that TLR4 exerts its detrimental metabolic effects in the myocardium through a cytokine-independent pathway.
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Affiliation(s)
- Ellen E. Jackson
- Department of Physiological Sciences, Oklahoma State University, Stillwater, Oklahoma, United States of America
| | - Elisabeth Rendina-Ruedy
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, Oklahoma, United States of America
| | - Brenda J. Smith
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, Oklahoma, United States of America
| | - Veronique A. Lacombe
- Department of Physiological Sciences, Oklahoma State University, Stillwater, Oklahoma, United States of America
- Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- * E-mail:
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