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Chargo NJ, Kang HJ, Das S, Jin Y, Rockwell C, Cho JY, McCabe LR, Parameswaran N. Korean red ginseng extract prevents bone loss in an oral model of glucocorticoid induced osteoporosis in mice. Front Pharmacol 2024; 15:1268134. [PMID: 38533264 PMCID: PMC10963623 DOI: 10.3389/fphar.2024.1268134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 02/20/2024] [Indexed: 03/28/2024] Open
Abstract
The gut microbiota and barrier function play important roles in bone health. We previously demonstrated that chronic glucocorticoid (GC)-induced bone loss in mice is associated with significant shifts in gut microbiota composition and impaired gut barrier function. Korean Red Ginseng (KRG, Panax Ginseng Meyer, Araliaceae) extract has been shown to prevent glucocorticoid-induced osteoporosis (GIO) in a subcutaneous pellet model in mice, but its effect on gut microbiota and barrier function in this context is not known. The overall goal of this study was to test the effect of KRG extract in a clinically relevant, oral model of GIO and further investigate its role in modulating the gut-bone axis. Growing male mice (CD-1, 8 weeks) were treated with 75 μg/mL corticosterone (∼9 mg/kg/day) or 0.4% ethanol vehicle in the drinking water for 4 weeks. During this 4-week period, mice were treated daily with 500 mg/kg/day KRG extract dissolved in sterile water or an equal amount of sterile water via oral gastric gavage. After 4 weeks of treatment, we assessed bone volume, microbiota composition, gut barrier integrity, and immune cells in the bone marrow (BM) and mesenteric lymph nodes (MLNs). 4 weeks of oral GC treatment caused significant distal femur trabecular bone loss, and this was associated with changes in gut microbiota composition, impaired gut barrier function and altered immune cell composition. Importantly, KRG extract prevented distal femur trabecular bone loss and caused significant alterations in gut microbiota composition but had only modest effects on gut barrier function and immune cell populations. Taken together, these results demonstrate that KRG extract significantly modulates the gut microbiota-bone axis and prevents glucocorticoid-induced bone loss in mice.
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Affiliation(s)
- Nicholas J. Chargo
- Department of Physiology, Michigan State University, East Lansing, MI, United States
- College of Osteopathic Medicine, Michigan State University, East Lansing, MI, United States
| | - Ho Jun Kang
- Department of Physiology, Michigan State University, East Lansing, MI, United States
| | - Subhashari Das
- Department of Physiology, Michigan State University, East Lansing, MI, United States
| | - Yining Jin
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, United States
| | - Cheryl Rockwell
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, United States
| | - Jae Youl Cho
- Department of Integrative Biotechnology, Sungkyunkwan University, Suwon, Republic of Korea
| | - Laura R. McCabe
- Department of Physiology, Michigan State University, East Lansing, MI, United States
- College of Osteopathic Medicine, Michigan State University, East Lansing, MI, United States
| | - Narayanan Parameswaran
- Department of Physiology, Michigan State University, East Lansing, MI, United States
- College of Human Medicine, Michigan State University, East Lansing, MI, United States
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Zhang J, Zhang X, Lu M, Chang Y, Wang Q, Tu J, Wu H, Wang C, Hong Z, Xiong M, Song L, Wei W. GRK2 Mediates Macrophage Polarization by Regulating EP4-cAMP-pCREB Signaling in Ulcerative Colitis and the Therapeutic Effect of Paroxetine on Mice with DSS-Induced Colitis. Pharmaceuticals (Basel) 2023; 16:ph16050664. [PMID: 37242446 DOI: 10.3390/ph16050664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 04/15/2023] [Accepted: 04/25/2023] [Indexed: 05/28/2023] Open
Abstract
G protein-coupled receptor kinase 2 (GRK2) is one of the cytosolic enzymes, and GRK2 translocation induces prostaglandin E2 receptor 4 (EP4) over-desensitization and reduces the level of cyclic adenosine monophosphate (cAMP) to regulate macrophage polarization. However, the role of GRK2 in the pathophysiology of ulcerative colitis (UC) remains unclear. In this study, we investigated the role of GRK2 in macrophage polarization in UC, using biopsies from patients, a GRK2 heterozygous mouse model with dextran sulfate sodium (DSS)-induced colitis, and THP-1 cells. The results showed that a high level of prostaglandin E2 (PGE2) stimulated the receptor EP4 and enhanced the transmembrane activity of GRK2 in colonic lamina propria mononuclear cells (LPMCs), resulting in a down-regulation of membrane EP4 expression. Then, the suppression of cAMP-cyclic AMP responsive element-binding (CREB) signal inhibited M2 polarization in UC. Paroxetine is acknowledged as one of the selective serotonin reuptake inhibitors (SSRI), which is also considered as a potent GRK2 inhibitor with a high selectivity for GRK2. We found that paroxetine could alleviate symptoms of DSS-induced colitis in mice by regulating GPCR signaling to affect macrophage polarization. Taken together, the current results show that GRK2 may act as a novel therapeutic target in UC by regulating macrophage polarization, and paroxetine as a GRK2 inhibitor may have therapeutic effect on mice with DSS-induced colitis.
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Affiliation(s)
- Jiawei Zhang
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-Inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Centre of Anti-Inflammatory and Immune Medicine, Hefei 230032, China
- Department of General Surgery, The First Affiliated Hospital of Anhui Medical University, Hefei 230022, China
| | - Xianzheng Zhang
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-Inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Centre of Anti-Inflammatory and Immune Medicine, Hefei 230032, China
| | - Mingdian Lu
- Department of General Surgery, The First Affiliated Hospital of Anhui Medical University, Hefei 230022, China
| | - Yan Chang
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-Inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Centre of Anti-Inflammatory and Immune Medicine, Hefei 230032, China
| | - Qingtong Wang
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-Inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Centre of Anti-Inflammatory and Immune Medicine, Hefei 230032, China
| | - Jiajie Tu
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-Inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Centre of Anti-Inflammatory and Immune Medicine, Hefei 230032, China
| | - Huaxun Wu
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-Inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Centre of Anti-Inflammatory and Immune Medicine, Hefei 230032, China
| | - Chun Wang
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-Inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Centre of Anti-Inflammatory and Immune Medicine, Hefei 230032, China
| | - Zhongyang Hong
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-Inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Centre of Anti-Inflammatory and Immune Medicine, Hefei 230032, China
| | - Maoming Xiong
- Department of General Surgery, The First Affiliated Hospital of Anhui Medical University, Hefei 230022, China
| | - Lihua Song
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-Inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Centre of Anti-Inflammatory and Immune Medicine, Hefei 230032, China
| | - Wei Wei
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-Inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Centre of Anti-Inflammatory and Immune Medicine, Hefei 230032, China
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Jiang M, Tang C, Yang M, Li Y, Wang W, Wang C, Wei W, Chen J. Paeoniflorin-6'-O-benzene sulfonate protected the intestinal epithelial barrier by restoring the inhibitory effect of GRK2 and β-arrestin 2 on ERK1/2-NF-κB. Phytother Res 2023; 37:743-758. [PMID: 36223242 DOI: 10.1002/ptr.7657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 07/02/2022] [Accepted: 07/09/2022] [Indexed: 11/11/2022]
Abstract
Peoniflorin-6'-O-benzene sulfonate (CP-25) inhibited the activity of GRK2 to exert anti-inflammatory and immunomodulatory effects. This study aimed to investigate the effect of CP-25 the intestinal epithelial barrier and the mechanism. CaCO-2 cell monolayer and dextran sulfate salt (DSS)-induced colitis mouse model was used to evaluate intestinal epithelial barrier function in vitro and in vivo, respectively. Results showed that CP-25 prevented dysfunction of the intestinal epithelial barrier and inhibited NF-κB p65 activation in TNF-α-induced CaCO-2 cells. The colon structure destroyed in DSS-induced colitis mice was improved by CP-25. CP-25 has a role in inhibition membrane translocation of GRK2-β-arrestin 2 complex, stabilization of the binding of GRK2 and β-arrestin 2 to ERK1/2 in cytoplasm. Subsequently down-regulated the nuclear transcription and transactivation of NF-κB p65 via inhibiting its phosphorylation of Ser536, and Ser276, respectively and restored the epithelial barrier function. In conclusion, CP-25 inhibited ERK1/2-NF-κB activation and thereby protected the intestinal epithelial barrier, which was associated with restoring the inhibition of GRK2 and β-arrestin 2 on ERK1/2.
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Affiliation(s)
- Mengya Jiang
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Hefei, People's Republic of China
| | - Caihong Tang
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Hefei, People's Republic of China
| | - Mei Yang
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Hefei, People's Republic of China
| | - Ying Li
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Hefei, People's Republic of China
| | - Wu Wang
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Hefei, People's Republic of China
| | - Chun Wang
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Hefei, People's Republic of China
| | - Wei Wei
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Hefei, People's Republic of China
| | - Jingyu Chen
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Hefei, People's Republic of China
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Cheng H, Guo P, Su T, Jiang C, Zhu Z, Wei W, Zhang L, Wang Q. G protein-coupled receptor kinase type 2 and β-arrestin2: Key players in immune cell functions and inflammation. Cell Signal 2022; 95:110337. [DOI: 10.1016/j.cellsig.2022.110337] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 04/15/2022] [Accepted: 04/15/2022] [Indexed: 02/07/2023]
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Abd Alla J, Quitterer U. The RAF Kinase Inhibitor Protein (RKIP): Good as Tumour Suppressor, Bad for the Heart. Cells 2022; 11:cells11040654. [PMID: 35203304 PMCID: PMC8869954 DOI: 10.3390/cells11040654] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 02/08/2022] [Accepted: 02/11/2022] [Indexed: 02/04/2023] Open
Abstract
The RAF kinase inhibitor protein, RKIP, is a dual inhibitor of the RAF1 kinase and the G protein-coupled receptor kinase 2, GRK2. By inhibition of the RAF1-MAPK (mitogen-activated protein kinase) pathway, RKIP acts as a beneficial tumour suppressor. By inhibition of GRK2, RKIP counteracts GRK2-mediated desensitisation of G protein-coupled receptor (GPCR) signalling. GRK2 inhibition is considered to be cardioprotective under conditions of exaggerated GRK2 activity such as heart failure. However, cardioprotective GRK2 inhibition and pro-survival RAF1-MAPK pathway inhibition counteract each other, because inhibition of the pro-survival RAF1-MAPK cascade is detrimental for the heart. Therefore, the question arises, what is the net effect of these apparently divergent functions of RKIP in vivo? The available data show that, on one hand, GRK2 inhibition promotes cardioprotective signalling in isolated cardiomyocytes. On the other hand, inhibition of the pro-survival RAF1-MAPK pathway by RKIP deteriorates cardiomyocyte viability. In agreement with cardiotoxic effects, endogenous RKIP promotes cardiac fibrosis under conditions of cardiac stress, and transgenic RKIP induces heart dysfunction. Supported by next-generation sequencing (NGS) data of the RKIP-induced cardiac transcriptome, this review provides an overview of different RKIP functions and explains how beneficial GRK2 inhibition can go awry by RAF1-MAPK pathway inhibition. Based on RKIP studies, requirements for the development of a cardioprotective GRK2 inhibitor are deduced.
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Affiliation(s)
- Joshua Abd Alla
- Molecular Pharmacology, Department of Chemistry and Applied Biosciences, ETH Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland;
| | - Ursula Quitterer
- Molecular Pharmacology, Department of Chemistry and Applied Biosciences, ETH Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland;
- Department of Medicine, Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
- Correspondence: ; Tel.: +41-44-632-9801
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Li Y, Jiang MY, Chen JY, Xu ZW, Zhang JW, Li T, Zhang LL, Wei W. CP-25 exerts therapeutic effects in mice with dextran sodium sulfate-induced colitis by inhibiting GRK2 translocation to downregulate the TLR4-NF-κB-NLRP3 inflammasome signaling pathway in macrophages. IUBMB Life 2021; 73:1406-1422. [PMID: 34590407 DOI: 10.1002/iub.2564] [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: 09/22/2021] [Accepted: 09/23/2021] [Indexed: 12/26/2022]
Abstract
Deficiency of G protein-coupled receptor kinase 2 (GRK2) was found to protect mice from dextran sulfate sodium (DSS)-induced colitis. Paeoniflorin-6'-O-benzene sulfonate (CP-25) has been shown to exert anti-inflammatory immune regulatory effects in animal models of inflammatory autoimmune disease. This study aimed to investigate the of GRK2 in the pathogenesis of ulcerative colitis (UC) and its effects on macrophage polarization, macrophage subtype regulation of intestinal barrier function, and therapeutic effects of CP-25 in mice with DSS-induced colitis. We found imbalanced macrophage polarization, intestinal barrier dysfunction, and abnormal activation of GRK2 and TLR4-NF-κB-NLRP3 inflammasome signaling pathway in the colonic mucosa of patients with UC. CP-25, restored the damaged intestinal barrier function by inhibiting the transmembrane region of GRK2 in macrophages stimulated by lipopolysaccharides. CP-25 exerted therapeutic effects by ameliorating clinical manifestation, regulating macrophage polarization, and restoring abnormally activated TLR4-NF-κB-NLRP3 inflammasome signaling pathway by inhibiting GRK2. These data suggest the pathogenesis of UC may be related to the imbalance of macrophage polarization, which leads to abnormal activation of TLR4-NF-κB-NLRP3 inflammasome signaling pathway mediated by GRK2 and destruction of the intestinal mucosal barrier. CP-25 confers therapeutic effects on colitis by inhibiting GRK2 translocation to induce the downregulation of TLR4-NF-κB-NLRP3 inflammasome signaling in macrophages.
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Affiliation(s)
- Ying Li
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Collaborative Innovation Center of Anti-inflammatory and Immune Medicines, Hefei, China
| | - Meng-Ya Jiang
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Collaborative Innovation Center of Anti-inflammatory and Immune Medicines, Hefei, China
| | - Jing-Yu Chen
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Collaborative Innovation Center of Anti-inflammatory and Immune Medicines, Hefei, China
| | - Zhou-Wei Xu
- Department of Emergency Surgery, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Jia-Wei Zhang
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Collaborative Innovation Center of Anti-inflammatory and Immune Medicines, Hefei, China.,Department of General Surgery, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Tao Li
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Collaborative Innovation Center of Anti-inflammatory and Immune Medicines, Hefei, China.,Department of Clinical Laboratory, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Ling-Ling Zhang
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Collaborative Innovation Center of Anti-inflammatory and Immune Medicines, Hefei, China
| | - Wei Wei
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Collaborative Innovation Center of Anti-inflammatory and Immune Medicines, Hefei, China
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Fuentes N, McCullough M, Panettieri RA, Druey KM. RGS proteins, GRKs, and beta-arrestins modulate G protein-mediated signaling pathways in asthma. Pharmacol Ther 2021; 223:107818. [PMID: 33600853 DOI: 10.1016/j.pharmthera.2021.107818] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/25/2021] [Indexed: 12/17/2022]
Abstract
Asthma is a highly prevalent disorder characterized by chronic lung inflammation and reversible airways obstruction. Pathophysiological features of asthma include episodic and reversible airway narrowing due to increased bronchial smooth muscle shortening in response to external and host-derived mediators, excessive mucus secretion into the airway lumen, and airway remodeling. The aberrant airway smooth muscle (ASM) phenotype observed in asthma manifests as increased sensitivity to contractile mediators (EC50) and an increase in the magnitude of contraction (Emax); collectively these attributes have been termed "airways hyper-responsiveness" (AHR). This defining feature of asthma can be promoted by environmental factors including airborne allergens, viruses, and air pollution and other irritants. AHR reduces airway caliber and obstructs airflow, evoking clinical symptoms such as cough, wheezing and shortness of breath. G-protein-coupled receptors (GPCRs) have a central function in asthma through their impact on ASM and airway inflammation. Many but not all treatments for asthma target GPCRs mediating ASM contraction or relaxation. Here we discuss the roles of specific GPCRs, G proteins, and their associated signaling pathways, in asthma, with an emphasis on endogenous mechanisms of GPCR regulation of ASM tone and lung inflammation including regulators of G-protein signaling (RGS) proteins, G-protein coupled receptor kinases (GRKs), and β-arrestin.
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Affiliation(s)
- Nathalie Fuentes
- Lung and Vascular Inflammation Section, Laboratory of Allergic Diseases, NIAID/NIH, Bethesda, MD, United States of America
| | - Morgan McCullough
- Lung and Vascular Inflammation Section, Laboratory of Allergic Diseases, NIAID/NIH, Bethesda, MD, United States of America
| | - Reynold A Panettieri
- Rutgers Institute for Translational Medicine and Science, Child Health Institute of New Jersey, Rutgers University School of Medicine, New Brunswick, NJ, United States of America
| | - Kirk M Druey
- Lung and Vascular Inflammation Section, Laboratory of Allergic Diseases, NIAID/NIH, Bethesda, MD, United States of America.
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Collins FL, Rios-Arce ND, Schepper JD, Jones AD, Schaefer L, Britton RA, McCabe LR, Parameswaran N. Beneficial effects of Lactobacillus reuteri 6475 on bone density in male mice is dependent on lymphocytes. Sci Rep 2019; 9:14708. [PMID: 31605025 PMCID: PMC6789011 DOI: 10.1038/s41598-019-51293-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 09/29/2019] [Indexed: 02/06/2023] Open
Abstract
Oral treatment with probiotic bacteria has been shown to prevent bone loss in multiple models of osteoporosis. In previous studies we demonstrated that oral administration of Lactobacillus reuteri in healthy male mice increases bone density. The host and bacterial mechanisms of these effects however are not well understood. The objective of this study was to understand the role of lymphocytes in mediating the beneficial effects of L. reuteri on bone health in male mice. We administered L. reuteri in drinking water for 4 weeks to wild type or Rag knockout (lack mature T and B lymphocytes) male mice. While L. reuteri treatment increased bone density in wild type, no significant increases were seen in Rag knockout mice, suggesting that lymphocytes are critical for mediating the beneficial effects of L. reuteri on bone density. To understand the effect of L. reuteri on lymphocytes in the intestinal tissues, we isolated mesenteric lymph node (MLN) from naïve wild type mice. In ex vivo studies using whole mesenteric lymph node (MLN) as well as CD3+ T-cells, we demonstrate that live L. reuteri and its secreted factors have concentration-dependent effects on the expression of cytokines, including anti-inflammatory cytokine IL-10. Fractionation studies identified that the active component of L. reuteri is likely water soluble and small in size (<3 kDa) and its effects on lymphocytes are negatively regulated by a RIP2 inhibitor, suggesting a role for NOD signaling. Finally, we show that T-cells from MLNs treated with L. reuteri supernatants, secrete factors that enhance osterix (transcription factor involved in osteoblast differentiation) expression in MC3T3-E1 osteoblasts. Together, these data suggest that L. reuteri secreted factors regulate T-lymphocytes which play an important role in mediating the beneficial effects of L. reuteri on bone density.
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Affiliation(s)
- Fraser L Collins
- Department of Physiology, Michigan State University, East Lansing, USA
| | - Naiomy Deliz Rios-Arce
- Department of Physiology, Michigan State University, East Lansing, USA
- Comparative Medicine and Integrative Biology Program, Michigan State University, East Lansing, Michigan, USA
| | | | - A Daniel Jones
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, USA
- Department of Chemistry, Michigan State University, East Lansing, USA
| | - Laura Schaefer
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, USA
| | - Robert A Britton
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, USA
| | - Laura R McCabe
- Department of Physiology, Michigan State University, East Lansing, USA.
| | - Narayanan Parameswaran
- Department of Physiology, Michigan State University, East Lansing, USA.
- Comparative Medicine and Integrative Biology Program, Michigan State University, East Lansing, Michigan, USA.
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