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Braga GDC, Simões JLB, Teixeira Dos Santos YJ, Filho JCM, Bagatini MD. The impacts of obesity in rheumatoid arthritis and insights into therapeutic purinergic modulation. Int Immunopharmacol 2024; 136:112357. [PMID: 38810303 DOI: 10.1016/j.intimp.2024.112357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 05/22/2024] [Accepted: 05/24/2024] [Indexed: 05/31/2024]
Abstract
Rheumatoid Arthritis (RA) is an autoimmune condition responsible for the impairment of synovia and joints, endangering the functionality of individuals and contributing to mortality. Currently, obesity is increasing worldwide, and recent studies have suggested an association between such condition and RA. In this sense, obese individuals present a lower capacity for achieving remission and present more intense symptoms of the disease, demonstrating a link between both disorders. Different studies aim to understand the possible connection between the conditions; however, few is known in this sense. Therefore, knowing that obesity can alter the activity of multiple body systems, this work's objective is to evaluate the main modifications caused by obesity, which can be linked to the pathophysiology of RA, highlighting as relevant topics obesity's negative impact triggering systemic inflammation, intestinal dysbiosis, endocrine disbalances. Furthermore, the relationship between oxidative stress and obesity also deserves to be highlighted, considering the influence of reactive oxygen species (ROS) accumulation in RA exacerbation. Additionally, many of those characteristics influenced by obesity, along with the classic peculiarities of RA pathophysiology, can also be associated with purinergic signaling. Hence, this work suggests possible connections between the purinergic system and RA, proposing potential therapeutic targets against RA to be studied.
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Di Vincenzo A, Granzotto M, Crescenzi M, Vettor R, Rossato M. Non-aromatizable androgens modulate the lipopolysaccharide induced expression of the P2X7 receptor in human adipocytes. Front Pharmacol 2023; 14:1251035. [PMID: 37936906 PMCID: PMC10627236 DOI: 10.3389/fphar.2023.1251035] [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: 06/30/2023] [Accepted: 10/02/2023] [Indexed: 11/09/2023] Open
Abstract
Introduction: The activation of the P2X7 receptor subtype (P2X7R) has a main role in orchestrating the cellular inflammatory response in many different tissues. Obesity is characterized by dysfunctional fat deposition leading to a tissue-specific and systemic low-grade inflammation. Androgens and estrogens contribute to the whole adipose tissue inflammatory state, but the involvement of sex steroids in the purinergic signaling modulation in adipocytes is still unknown. Methods: We performed an in vitro study to evaluate the possible role of sex hormones on the P2X7R gene expression in human adipocytes, at baseline and after stimulation with bacterial lipopolysaccharide (LPS). We evaluated P2X7R gene expression during in vitro differentiation of human adipocytes, in the absence and presence of testosterone (T) and 17β-estradiol (E2) in the presence and absence of LPS. Furthermore, we analyzed the effects of incubation with dihydrotestosterone (DHT), a non-aromatizable androgen, using the co-incubation of isolated human adipocytes with T alone or in combination with anastrozole, an inhibitor of aromatase, the enzyme responsible of T conversion to E2. Results: At baseline, incubation of adipocytes with T or E2 did not significantly affect P2X7R gene expression. On the contrary, the incubation with DHT was associated with a significant reduction of P2X7R gene expression. LPS incubation significantly increased gene expression of P2X7R with respect to baseline. Interestingly, after LPS stimulation, DHT exposure showed an additional effect, markedly increasing the P2X7R gene expression. This amplificatory effect was confirmed by the incubation of adipocytes to both anastrozole and testosterone. In these experimental conditions, while no effect was observed at baseline, an amplification of the expression of the P2X7R mRNA was observed after stimulation with LPS. Discussion: The purinergic system is involved in the inflammatory response of adipocytes, and androgens may modulate its activity. In particular DHT, a non-aromatizable androgen, amplifies the LPS-induced P2X7R gene expression in human adipocytes thus showing a gender regulated response of the expression of this purinergic receptor strongly involved in the inflammatory response in adipose tissue.
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Affiliation(s)
| | | | | | | | - Marco Rossato
- Internal Medicine, Department of Medicine—DIMED, University Hospital of Padova, Padova, Italy
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Mathias LS, Herman-de-Sousa C, Cury SS, Nogueira CR, Correia-de-Sá P, de Oliveira M. RNA-seq reveals that anti-obesity irisin and triiodothyronine (T3) hormones differentially affect the purinergic signaling transcriptomics in differentiated human adipocytes. Biochim Biophys Acta Mol Cell Biol Lipids 2023; 1868:159276. [PMID: 36642213 DOI: 10.1016/j.bbalip.2022.159276] [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: 07/14/2022] [Revised: 12/05/2022] [Accepted: 12/15/2022] [Indexed: 01/15/2023]
Abstract
The anti-obesity thyroid hormone, triiodothyronine (T3), and irisin, an exercise- and/or cold-induced myokine, stimulate thermogenesis and energy consumption while decreasing lipid accumulation. The involvement of ATP signaling in adipocyte cell function and obesity has attracted increasing attention, but the crosstalk between the purinergic signaling cascade and anti-obesity hormones lacks experimental evidence. In this study, we investigated the effects of T3 and irisin in the transcriptomics of membrane-bound purinoceptors, ectonucleotidase enzymes and nucleoside transporters participating in the purinergic signaling in cultured human adipocytes. The RNA-seq analysis revealed that differentiated adipocytes express high amounts of ADORA1, P2RY11, P2RY12, and P2RX6 gene transcripts, along with abundant levels of transcriptional products encoding to purine metabolizing enzymes (ENPP2, ENPP1, NT5E, ADA and ADK) and transporters (SLC29A1, SCL29A2). The transcriptomics of purinergic signaling markers changed in parallel to the upsurge of "browning" adipocyte markers, like UCP1 and P2RX5, after treatment with T3 and irisin. Upregulation of ADORA1, ADORA2A and P2RX4 gene transcription was obtained with irisin, whereas T3 preferentially upregulated NT5E, SLC29A2 and P2RY11 genes. Irisin was more powerful than T3 towards inhibition of the leptin gene transcription, the SCL29A1 gene encoding for the ENT1 transporter, the E-NPP2 (autotaxin) gene, and genes that encode for two ADP-sensitive P2Y receptors, P2RY1 and P2RY12. These findings indicate that anti-obesity irisin and T3 hormones differentially affect the purinergic signaling transcriptomics, which might point towards new directions for the treatment of obesity and related metabolic disorders that are worth to be pursued in future functional studies.
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Affiliation(s)
- Lucas Solla Mathias
- Department of Internal Clinic, Botucatu Medical School, São Paulo State University (UNESP), Botucatu, São Paulo, Brazil
| | - Carina Herman-de-Sousa
- Laboratório de Farmacologia e Neurobiologia, Departamento de Imuno-Fisiologia e Farmacologia, Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto (ICBAS-UP), Porto, Portugal
| | - Sarah Santiloni Cury
- Department of Structural and Functional Biology, Institute of Biosciences, São Paulo State University (UNESP), Botucatu, São Paulo, Brazil
| | - Célia Regina Nogueira
- Department of Internal Clinic, Botucatu Medical School, São Paulo State University (UNESP), Botucatu, São Paulo, Brazil
| | - Paulo Correia-de-Sá
- Laboratório de Farmacologia e Neurobiologia, Departamento de Imuno-Fisiologia e Farmacologia, Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto (ICBAS-UP), Porto, Portugal; Center for Drug Discovery and Innovative Medicines (MedInUP), ICBAS-UP, Porto, Portugal.
| | - Miriane de Oliveira
- Department of Internal Clinic, Botucatu Medical School, São Paulo State University (UNESP), Botucatu, São Paulo, Brazil
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Purinergic receptor: a crucial regulator of adipose tissue functions. Purinergic Signal 2023; 19:273-281. [PMID: 36515790 PMCID: PMC9984650 DOI: 10.1007/s11302-022-09907-w] [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: 11/01/2021] [Accepted: 11/14/2022] [Indexed: 12/15/2022] Open
Abstract
Obesity is a public-health challenge resulting from an imbalance between energy expenditure and calorie intake. This health problem exacerbates a variety of metabolic complications worldwide. Adipose tissue is an essential regulator of energy homeostasis, and the functions within it are regulated by purinergic receptors. A1R, P2X7R, and P2YR mainly mediate energy homeostasis primarily through regulating energy storage and adipokines secretion in white adipose tissue (WAT). P2X5R is a novel-specific cell surface marker in brown/beige adipocytes. A2R is a promising therapeutic target for stimulating energy expenditure in brown adipose tissue (BAT) and also mediating WAT browning. Based on these features, purinergic receptors may be an appropriate target in treating obesity. In this review, the role of purinergic receptors in different types of adipose tissue is summarized. An improved understanding of purinergic receptor functions in adipose tissue may lead to more effective treatment interventions for obesity and its related metabolic disorders.
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Amoafo EB, Entsie P, Albayati S, Dorsam GP, Kunapuli SP, Kilpatrick LE, Liverani E. Sex-related differences in the response of anti-platelet drug therapies targeting purinergic signaling pathways in sepsis. Front Immunol 2022; 13:1015577. [PMID: 36405709 PMCID: PMC9667743 DOI: 10.3389/fimmu.2022.1015577] [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: 08/09/2022] [Accepted: 10/10/2022] [Indexed: 01/24/2023] Open
Abstract
Sepsis, a complex clinical syndrome resulting from a serious infection, is a major healthcare problem associated with high mortality. Sex-related differences in the immune response to sepsis have been proposed but the mechanism is still unknown. Purinergic signaling is a sex-specific regulatory mechanism in immune cell physiology. Our studies have shown that blocking the ADP-receptor P2Y12 but not P2Y1 receptor was protective in male mice during sepsis, but not female. We now hypothesize that there are sex-related differences in modulating P2Y12 or P2Y1 signaling pathways during sepsis. Male and female wild-type (WT), P2Y12 knock-out (KO), and P2Y1 KO mice underwent sham surgery or cecal ligation and puncture (CLP) to induce sepsis. The P2Y12 antagonist ticagrelor or the P2Y1 antagonist MRS2279 were administered intra-peritoneally after surgery to septic male and female mice. Blood, lungs and kidneys were collected 24 hours post-surgery. Sepsis-induced changes in platelet activation, secretion and platelet interaction with immune cells were measured by flow cytometry. Neutrophil infiltration in the lung and kidney was determined by a myeloperoxidase (MPO) colorimetric assay kit. Sepsis-induced platelet activation, secretion and aggregate formation were reduced in male CLP P2Y12 KO and in female CLP P2Y1 KO mice compared with their CLP WT counterpart. Sepsis-induced MPO activity was reduced in male CLP P2Y12 KO and CLP P2Y1 KO female mice. CLP males treated with ticagrelor or MRS2279 showed a decrease in sepsis-induced MPO levels in lung and kidneys, aggregate formation, and platelet activation as compared to untreated male CLP mice. There were no differences in platelet activation, aggregate formation, and neutrophil infiltration in lung and kidney between female CLP mice and female CLP mice treated with ticagrelor or MRS2279. In human T lymphocytes, blocking P2Y1 or P2Y12 alters cell growth and secretion in vitro in a sex-dependent manner, supporting the data obtained in mice. In conclusion, targeting purinergic signaling represents a promising therapy for sepsis but drug targeting purinergic signaling is sex-specific and needs to be investigated to determine sex-related targeted therapies in sepsis.
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Affiliation(s)
- Emmanuel Boadi Amoafo
- Department of Pharmaceutical Sciences, School of Pharmacy, College of Health Professions, North Dakota State University, Fargo, ND, United States
| | - Philomena Entsie
- Department of Pharmaceutical Sciences, School of Pharmacy, College of Health Professions, North Dakota State University, Fargo, ND, United States
| | - Samara Albayati
- Sol Sherry Thrombosis Research Center, Temple University School of Medicine, Temple University Hospital, Philadelphia, PA, United States
| | - Glenn P. Dorsam
- Center for Inflammation and Lung Research, Department of Microbiology, Immunology and Inflammation, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Satya P. Kunapuli
- Sol Sherry Thrombosis Research Center, Temple University School of Medicine, Temple University Hospital, Philadelphia, PA, United States
| | - Laurie E. Kilpatrick
- Department of Microbiological Sciences, College of Agriculture, Food Systems and Natural Resources, North Dakota State University, Fargo, ND, United States
| | - Elisabetta Liverani
- Department of Pharmaceutical Sciences, School of Pharmacy, College of Health Professions, North Dakota State University, Fargo, ND, United States
- Sol Sherry Thrombosis Research Center, Temple University School of Medicine, Temple University Hospital, Philadelphia, PA, United States
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The purinergic signalling and inflammation in the pathogenesis and progression of diabetes: key factors and therapeutic targets. Inflamm Res 2022; 71:759-770. [PMID: 35648156 DOI: 10.1007/s00011-022-01587-x] [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: 02/23/2022] [Accepted: 05/10/2022] [Indexed: 11/27/2022] Open
Abstract
Type 2 diabetes mellitus (T2DM) is an important chronic disease around the world, and according to the World Health Organization, it is the 9th principal cause of global death. This pathology is characterized by high levels of circulating glucose as a result of insulin resistance, and it is well stated that inflammation related to obesity is directly associated with the development of the disease. The purinergic signalling is involved in both pancreatic destruction, which impairs insulin secretion, and the cytokine production that favors insulin resistance in T2DM. In this review, the purinergic signalling aspects will be discussed, showing the impact of the enzymes, nucleotides, nucleosides, and receptors of this system and the cytokines that result in inflammation, in the development and progression of T2DM, besides, pointing the purinergic receptors as a possible therapeutic approach.
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Chiang CH, Cheng CY, Lien YT, Huang KC, Lin WW. P2X7 Activation Enhances Lipid Accumulation During Adipocytes Differentiation Through Suppressing the Expression of Sirtuin-3, Sirtuin-5, and Browning Genes. Front Pharmacol 2022; 13:852858. [PMID: 35462937 PMCID: PMC9019299 DOI: 10.3389/fphar.2022.852858] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 03/18/2022] [Indexed: 11/24/2022] Open
Abstract
P2X7 signaling has been explored in adipose tissue because of its potential to promote ATP-activated inflammatory cascades during obesogenic environments. However, limited literature has investigated the role of the P2X7 receptor in lipid metabolism during adipocyte differentiation. This study sought to explore the regulatory roles of P2X7 in adipocytes. This study utilized the in vitro 3T3-L1 differentiation model. Lipid accumulation, intracellular triglyceride, and extracellular glycerol were determined. The selective P2X7 agonist BzATP and antagonist A438079 were administered to investigate the functions of P2X7. We found that the expression of P2X7 and the lipid accumulation increased during adipocyte differentiation from D0 to D4. When administered at D0/D2, A438079 attenuated, while BzATP enhanced the degree of lipid accumulation during adipocyte differentiation. Neither did BzATP and A438079 administration affect the expression of PPARγ and C/EBPα genes that increased at D4. In addition, both intracellular triglyceride and extracellular glycerol levels at D4 were reduced by A438079 treatment and enhanced by BzATP administration. When administered at stage 2 of adipocyte differentiation, BzATP consistently enhanced lipid accumulation and intracellular triglyceride and extracellular glycerol levels without affecting mRNA and protein levels of PPARγ and C/EBPα that increased at D4. However, treating A438079 or BzATP at D4 did not affect intracellular triglyceride formation and extracellular glycerol release in differentiated adipocytes at D7. Notably, BzATP administration at stage 2 exerted a concentration-dependent inhibition on the enhanced expression of PRDM16, PGC-1α, and UCP-1 at D4. Furthermore, BzATP administration at D0/D2 inhibited the protein and mRNA levels of sirtuin-3/5 at D4. BzATP treatment at stage 2 also suppressed the mRNA levels of sirtuin-3/5 genes upregulated by insulin. In conclusion, this study demonstrated P2X7 enhances lipid accumulation during adipogenesis by suppressing the expression of sirtuin-3/5 and the browning genes.
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Affiliation(s)
- Chien-Hsieh Chiang
- Graduate Institute of Pharmacology, National Taiwan University College of Medicine, Taipei, Taiwan.,Department of Family Medicine, National Taiwan University Hospital & College of Medicine, Taipei, Taiwan
| | - Ching-Yuan Cheng
- Graduate Institute of Pharmacology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Yi-Ting Lien
- Department of Family Medicine, National Taiwan University Hospital & College of Medicine, Taipei, Taiwan
| | - Kuo-Chin Huang
- Department of Family Medicine, National Taiwan University Hospital & College of Medicine, Taipei, Taiwan
| | - Wan-Wan Lin
- Graduate Institute of Pharmacology, National Taiwan University College of Medicine, Taipei, Taiwan.,Graduate Institute of Medical Sciences, Taipei Medical University, Taipei, Taiwan
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8
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Cai X, Yao Y, Teng F, Li Y, Wu L, Yan W, Lin N. The role of P2X7 receptor in infection and metabolism: Based on inflammation and immunity. Int Immunopharmacol 2021; 101:108297. [PMID: 34717202 DOI: 10.1016/j.intimp.2021.108297] [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: 06/10/2021] [Revised: 10/15/2021] [Accepted: 10/19/2021] [Indexed: 12/20/2022]
Abstract
The P2X7 receptor (P2X7R) is a ligand-gated receptor belonging to the P2 receptor family. It is distributed in various tissues of the human body and is involved in regulating the physiological functions of tissues and cells to affect the occurrence and development of diseases. Unlike all other P2 receptors, the P2X7 receptor is mainly expressed in immune cells and can be activated not only by extracellular nucleotides but also by non-nucleotide substances which act as positive allosteric modulators. In this review, we comprehensively describe the role of the P2X7 receptor in infection and metabolism based on its role as an important regulator of inflammation and immunity, and briefly introduce the structure and general function of the P2X7 receptor. These provide a clear knowledge framework for the study of the P2X7 receptor in human health. Targeting the P2X7 receptor may be an effective method for the treatment of inflammatory and immune diseases. And its role in microbial infection and metabolism may be the main direction for in-depth research on the P2X7 receptor in the future.
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Affiliation(s)
- Xiaoyu Cai
- Department of Clinical Pharmacology, Key Laboratory of Clinical Cancer Pharmacology and Toxicology Research of Zhejiang Province, Affiliated Hangzhou First People's Hospital, Cancer Center, Zhejiang University School of Medicine, Hangzhou 310006, China
| | - Yao Yao
- Department of Pharmacy, Women's Hospital School of Medicine Zhejiang University, Hangzhou 310006, China
| | - Fei Teng
- College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou 310053, China
| | - Yangling Li
- Department of Clinical Pharmacology, Key Laboratory of Clinical Cancer Pharmacology and Toxicology Research of Zhejiang Province, Affiliated Hangzhou First People's Hospital, Cancer Center, Zhejiang University School of Medicine, Hangzhou 310006, China
| | - Linwen Wu
- Department of Clinical Pharmacology, Key Laboratory of Clinical Cancer Pharmacology and Toxicology Research of Zhejiang Province, Affiliated Hangzhou First People's Hospital, Cancer Center, Zhejiang University School of Medicine, Hangzhou 310006, China
| | - Wei Yan
- Department of Clinical Pharmacology, Key Laboratory of Clinical Cancer Pharmacology and Toxicology Research of Zhejiang Province, Affiliated Hangzhou First People's Hospital, Cancer Center, Zhejiang University School of Medicine, Hangzhou 310006, China.
| | - Nengming Lin
- Department of Clinical Pharmacology, Key Laboratory of Clinical Cancer Pharmacology and Toxicology Research of Zhejiang Province, Affiliated Hangzhou First People's Hospital, Cancer Center, Zhejiang University School of Medicine, Hangzhou 310006, China; College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou 310053, China.
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Hixson EA, Borker PV, Jackson EK, Macatangay BJ. The Adenosine Pathway and Human Immunodeficiency Virus-Associated Inflammation. Open Forum Infect Dis 2021; 8:ofab396. [PMID: 34557556 PMCID: PMC8454523 DOI: 10.1093/ofid/ofab396] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 07/23/2021] [Indexed: 12/15/2022] Open
Abstract
Human immunodeficiency virus (HIV) is associated with an increased risk of age-associated comorbidities and mortality compared to people without HIV. This has been attributed to HIV-associated chronic inflammation and immune activation despite viral suppression. The adenosine pathway is an established mechanism by which the body regulates persistent inflammation to limit tissue damage associated with inflammatory conditions. However, HIV infection is associated with derangements in the adenosine pathway that limits its ability to control HIV-associated inflammation. This article reviews the function of purinergic signaling and the role of the adenosine signaling pathway in HIV-associated chronic inflammation. This review also discusses the beneficial and potential detrimental effects of pharmacotherapeutic strategies targeting this pathway among people with HIV.
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Affiliation(s)
- Emily A Hixson
- Department of Infectious Disease and Microbiology, University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania, USA
| | - Priya V Borker
- Division of Pulmonary Allergy and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Edwin K Jackson
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Bernard J Macatangay
- Department of Infectious Disease and Microbiology, University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania, USA.,Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pennsylvania, USA
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Activation of Cx43 Hemichannels Induces the Generation of Ca 2+ Oscillations in White Adipocytes and Stimulates Lipolysis. Int J Mol Sci 2021; 22:ijms22158095. [PMID: 34360859 PMCID: PMC8347185 DOI: 10.3390/ijms22158095] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 07/22/2021] [Accepted: 07/26/2021] [Indexed: 12/11/2022] Open
Abstract
The aim of the study was to investigate the mechanisms of Ca2+ oscillation generation upon activation of connexin-43 and regulation of the lipolysis/lipogenesis balance in white adipocytes through vesicular ATP release. With fluorescence microscopy it was revealed that a decrease in the concentration of extracellular calcium ([Ca2+]ex) results in two types of Ca2+ responses in white adipocytes: Ca2+ oscillations and transient Ca2+ signals. It was found that activation of the connexin half-channels is involved in the generation of Ca2+ oscillations, since the blockers of the connexin hemichannels-carbenoxolone, octanol, proadifen and Gap26-as well as Cx43 gene knockdown led to complete suppression of these signals. The activation of Cx43 in response to the reduction of [Ca2+]ex was confirmed by TIRF microscopy. It was shown that in response to the activation of Cx43, ATP-containing vesicles were released from the adipocytes. This process was suppressed by knockdown of the Cx43 gene and by bafilomycin A1, an inhibitor of vacuolar ATPase. At the level of intracellular signaling, the generation of Ca2+ oscillations in white adipocytes in response to a decrease in [Ca2+]ex occurred due to the mobilization of the Ca2+ ions from the thapsigargin-sensitive Ca2+ pool of IP3R as a result of activation of the purinergic P2Y1 receptors and phosphoinositide signaling pathway. After activation of Cx43 and generation of the Ca2+ oscillations, changes in the expression levels of key genes and their encoding proteins involved in the regulation of lipolysis were observed in white adipocytes. This effect was accompanied by a decrease in the number of adipocytes containing lipid droplets, while inhibition or knockdown of Cx43 led to inhibition of lipolysis and accumulation of lipid droplets. In this study, we investigated the mechanism of Ca2+ oscillation generation in white adipocytes in response to a decrease in the concentration of Ca2+ ions in the external environment and established an interplay between periodic Ca2+ modes and the regulation of the lipolysis/lipogenesis balance.
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Jorquera G, Meneses-Valdés R, Rosales-Soto G, Valladares-Ide D, Campos C, Silva-Monasterio M, Llanos P, Cruz G, Jaimovich E, Casas M. High extracellular ATP levels released through pannexin-1 channels mediate inflammation and insulin resistance in skeletal muscle fibres of diet-induced obese mice. Diabetologia 2021; 64:1389-1401. [PMID: 33710396 DOI: 10.1007/s00125-021-05418-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 12/22/2020] [Indexed: 02/06/2023]
Abstract
AIMS/HYPOTHESIS Skeletal muscle is a key target organ for insulin's actions and is the main regulator of blood glucose. In obese individuals and animal models, there is a chronic low-grade inflammatory state affecting highly metabolic organs, leading to insulin resistance. We have described that adult skeletal muscle fibres can release ATP to the extracellular medium through pannexin-1 (PANX1) channels. Besides, it is known that high extracellular ATP concentrations can act as an inflammatory signal. Here, we propose that skeletal muscle fibres from obese mice release high levels of ATP, through PANX1 channels, promoting inflammation and insulin resistance in muscle cells. METHODS C57BL/6J mice were fed with normal control diet (NCD) or high-fat diet (HFD) for 8 weeks. Muscle fibres were isolated from flexor digitorum brevis (FDB) muscle. PANX1-knockdown FDB fibres were obtained by in vivo electroporation of a short hairpin RNA Panx1 plasmid. We analysed extracellular ATP levels in a luciferin/luciferase assay. Gene expression was studied with quantitative real-time PCR (qPCR). Protein levels were evaluated by immunoblots, ELISA and immunofluorescence. Insulin sensitivity was analysed in a 2-NBDG (fluorescent glucose analogue) uptake assay, immunoblots and IPGTT. RESULTS HFD-fed mice showed significant weight gain and insulin resistance compared with NCD-fed mice. IL-6, IL-1β and TNF-α protein levels were increased in FDB muscle from obese mice. We observed high levels of extracellular ATP in muscle fibres from obese mice (197 ± 55 pmol ATP/μg RNA) compared with controls (32 ± 10 pmol ATP/μg RNA). ATP release in obese mice fibres was reduced by application of 100 μmol/l oleamide (OLE) and 5 μmol/l carbenoxolone (CBX), both PANX1 blockers. mRNA levels of genes linked to inflammation were reduced using OLE, CBX or 2 U/ml ATPase apyrase in muscle fibres from HFD-fed mice. In fibres from mice with pannexin-1 knockdown, we observed diminished extracellular ATP levels (78 ± 10 pmol ATP/μg RNA vs 252 ± 37 pmol ATP/μg RNA in control mice) and a lower expression of inflammatory markers. Moreover, a single pulse of 300 μmol/l ATP to fibres from control mice reduced insulin-mediated 2-NBDG uptake and promoted an elevation in mRNA levels of inflammatory markers. PANX-1 protein levels were increased two- to threefold in skeletal muscle from obese mice compared with control mice. Incubation with CBX increased Akt activation and 2-NBDG uptake in HFD fibres after insulin stimulation, rescuing the insulin resistance condition. Finally, in vivo treatment of HFD-fed mice with CBX (i.p. injection of 10 mg/kg each day) for 14 days, compared with PBS, reduced extracellular ATP levels in skeletal muscle fibres (51 ± 10 pmol ATP/μg RNA vs 222 ± 28 pmol ATP/μg RNA in PBS-treated mice), diminished inflammation and improved glycaemic management. CONCLUSIONS/INTERPRETATION In this work, we propose a novel mechanism for the development of inflammation and insulin resistance in the skeletal muscle of obese mice. We found that high extracellular ATP levels, released by overexpressed PANX1 channels, lead to an inflammatory state and insulin resistance in skeletal muscle fibres of obese mice.
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Affiliation(s)
- Gonzalo Jorquera
- Centro de Neurobiología y Fisiopatología Integrativa (CENFI), Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.
- Centro de Estudios de Ejercicio, Metabolismo y Cáncer, Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
| | - Roberto Meneses-Valdés
- Centro de Estudios de Ejercicio, Metabolismo y Cáncer, Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Giovanni Rosales-Soto
- Centro de Estudios de Ejercicio, Metabolismo y Cáncer, Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Facultad de Ciencias de la Educación, Universidad San Sebastián, sede Bellavista, Santiago, Chile
| | | | - Cristian Campos
- Centro de Estudios de Ejercicio, Metabolismo y Cáncer, Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Mónica Silva-Monasterio
- Centro de Estudios de Ejercicio, Metabolismo y Cáncer, Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Paola Llanos
- Instituto de Investigación en Ciencias Odontológicas, Facultad de Odontología, Universidad de Chile, Santiago, Chile
| | - Gonzalo Cruz
- Centro de Neurobiología y Fisiopatología Integrativa (CENFI), Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Enrique Jaimovich
- Centro de Estudios de Ejercicio, Metabolismo y Cáncer, Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Mariana Casas
- Centro de Estudios de Ejercicio, Metabolismo y Cáncer, Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
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12
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Jain S, Jacobson KA. Purinergic signaling in diabetes and metabolism. Biochem Pharmacol 2020; 187:114393. [PMID: 33359363 DOI: 10.1016/j.bcp.2020.114393] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 12/21/2020] [Accepted: 12/22/2020] [Indexed: 12/22/2022]
Abstract
Purinergic signaling, a concept originally formulated by the late Geoffrey Burnstock (1929-2020), was found to modulate pathways in every physiological system. In metabolic disorders there is a role for both adenosine receptors and P2 (nucleotide) receptors, of which there are two classes, i.e. P2Y metabotropic and P2X ionotropic receptors. The individual roles of the 19 receptors encompassed by this family have been dissected - and in many cases the effects associated with specific cell types, including adipocytes, skeletal muscle, liver cells and immune cells. It is suggested that ligands selective for each of the four adenosine receptors (A1, A2A, A2B and A3), and several of the P2 subtypes (e.g. P2Y6 or P2X7 antagonists) might have therapeutic potential for treating diabetes and obesity. This is a developing story with some conflicting conclusions relevant to drug discovery, which we summarize here.
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Affiliation(s)
- Shanu Jain
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Kenneth A Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA.
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The P2X7 ion channel is dispensable for energy and metabolic homeostasis of white and brown adipose tissues. Purinergic Signal 2020; 16:529-542. [PMID: 33025427 PMCID: PMC7855144 DOI: 10.1007/s11302-020-09738-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 09/20/2020] [Indexed: 12/12/2022] Open
Abstract
Several studies suggest a role of extracellular adenine nucleotides in regulating adipose tissue functions via the purinergic signaling network. Metabolic studies in mice with global deletion of the purinergic receptor P2X7 on the C57BL/6 background indicate that this receptor has only a minor role in adipose tissue for diet-induced inflammation or cold-triggered thermogenesis. However, recent data show that a polymorphism (P451L) present in C57BL/6 mice attenuates P2X7 receptor function, whereas BALB/c mice express the fully functional P451 allele. To determine the potential role of P2rx7 under metabolic and thermogenic stress conditions, we performed comparative studies using male P2rx7 knockout (KO) and respective wild-type controls on both BALB/c and C57BL/6 backgrounds. Our data show that adipose P2rx7 mRNA levels are increased in obese mice. Moreover, P2rx7 deficiency results in reduced levels of circulating CCL2 and IL6 with a moderate effect on gene expression of pro-inflammatory markers in white adipose tissue and liver of BALB/c and C57BL/6 mice. However, P2X7 expression does not alter body weight, insulin resistance, and hyperglycemia associated with high-fat diet feeding on both genetic backgrounds. Furthermore, deficiency of P2rx7 is dispensable for energy expenditure at thermoneutral and acute cold exposure conditions. In summary, these data show that-apart from a moderate effect on inflammatory cytokines-P2X7 plays only a minor role in inflammatory and thermogenic effects of white and brown adipose tissue even on the BALB/c background.
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de Oliveira M, Mathias LS, de Sibio MT, Noronha-Matos JB, Costa MA, Nogueira CR, Correia-de-Sá P. Pitfalls and challenges of the purinergic signaling cascade in obesity. Biochem Pharmacol 2020; 182:114214. [PMID: 32905795 DOI: 10.1016/j.bcp.2020.114214] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 08/31/2020] [Accepted: 09/01/2020] [Indexed: 12/15/2022]
Abstract
Obesity is a worldwide health problem which have reached pandemic proportions, now also including low and middle-income countries. Excessive or abnormal fat deposition in the abdomen especially in the visceral compartment is tightly associated with a high metabolic risk for arterial hypertension, type II diabetes, cardiovascular diseases, musculoskeletal disorders (especially articular degeneration) and some cancers. Contrariwise, accumulation of fat in the subcutaneous compartment has been associated with a neutral metabolic impact, favoring a lower risk of insulin resistance. Obesity results more often from an avoidable imbalance between food consumption and energy expenditure. There are several recommended strategies for dealing with obesity, including pharmacological therapies, but their success remains incomplete and may not compensate the associated adverse effects. Purinergic signaling operated by ATP and its metabolite, adenosine, has attracted increasing attention in obesity. The extracellular levels of purines often reflect the energy status of a given cell population. Adenine nucleotides and nucleosides fine tuning control adipogenesis and mature adipocytes function via the activation of P2 and P1 purinoceptors, respectively. These features make the purinergic signaling cascade a putative target for therapeutic intervention in obesity and related metabolic syndromes. There are, however, gaps in our knowledge regarding the role of purines in adipocyte precursors differentiation and mature adipocytes functions, as well as their impact among distinct adipose tissue deposits (e.g. white vs. brown, visceral vs. subcutaneous), which warrants further investigations before translation to clinical trials can be made.
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Affiliation(s)
- Miriane de Oliveira
- São Paulo State University (UNESP), Botucatu Medical School, District of Rubião Jr, s/n, 18618-000, Botucatu, São Paulo, Brazil
| | - Lucas Solla Mathias
- São Paulo State University (UNESP), Botucatu Medical School, District of Rubião Jr, s/n, 18618-000, Botucatu, São Paulo, Brazil
| | - Maria Teresa de Sibio
- São Paulo State University (UNESP), Botucatu Medical School, District of Rubião Jr, s/n, 18618-000, Botucatu, São Paulo, Brazil
| | - José Bernardo Noronha-Matos
- Laboratório de Farmacologia e Neurobiologia, Departamento de Imuno-Fisiologia e Farmacologia, Instituto de Ciências Biomédicas Abel Salazar - Universidade do Porto (ICBAS-UP); Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas Abel Salazar - Universidade do Porto (ICBAS-UP)
| | - Maria Adelina Costa
- Laboratório de Farmacologia e Neurobiologia, Departamento de Imuno-Fisiologia e Farmacologia, Instituto de Ciências Biomédicas Abel Salazar - Universidade do Porto (ICBAS-UP); Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas Abel Salazar - Universidade do Porto (ICBAS-UP); Departamento de Química, Instituto de Ciências Biomédicas Abel Salazar - Universidade do Porto (ICBAS-UP)
| | - Célia Regina Nogueira
- São Paulo State University (UNESP), Botucatu Medical School, District of Rubião Jr, s/n, 18618-000, Botucatu, São Paulo, Brazil
| | - Paulo Correia-de-Sá
- Laboratório de Farmacologia e Neurobiologia, Departamento de Imuno-Fisiologia e Farmacologia, Instituto de Ciências Biomédicas Abel Salazar - Universidade do Porto (ICBAS-UP); Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas Abel Salazar - Universidade do Porto (ICBAS-UP).
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Coccurello R, Volonté C. P2X7 Receptor in the Management of Energy Homeostasis: Implications for Obesity, Dyslipidemia, and Insulin Resistance. Front Endocrinol (Lausanne) 2020; 11:199. [PMID: 32528404 PMCID: PMC7247848 DOI: 10.3389/fendo.2020.00199] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 03/19/2020] [Indexed: 12/15/2022] Open
Abstract
Whole-body energy metabolism entails the highly regulated balance between food intake, nutrient breakdown, energy generation (ATP), and energy storage for the preservation of vital functions and body mass. Purinergic signaling has attracted increasing attention in the regulatory mechanisms not only for the reverse processes of white adipose tissue lipogenesis and lipolysis, but also for brown adipocyte-dependent thermogenesis and leptin production. This regulatory role has remarkable implications in the handling of body's energy expenditure and energy reservoir. Hence, selected purinergic receptors can play a relevant function in lipid metabolism, endocrine activity, glucose uptake, ATP-dependent increased expression of uncoupling protein 1, and browning of adipose tissue. Indeed, purinergic P2 receptors regulate adipogenesis and lipid metabolism and are involved in adipogenic differentiation. In particular, the ionotropic ATP-activated P2X7 subtype is involved in fat distribution, as well as in the modulation of inflammatory pathways in white adipose tissue. Within this context, very recent evidence has established a direct function of P2X7 in energy metabolism. Specifically, either genetic deletion (P2X7 knockout mice) or subchronic pharmacological inhibition of the receptor produces a decrease of whole-body energy expenditure and, concurrently, an increase of carbohydrate oxidation. As further evidence, lipid accumulation, increased fat mass distribution, and weight gain are reported in P2X7-depleted mice. Conversely, the stimulation of P2X7 enhances energy expenditure. Altogether, this knowledge supports the role of P2X7 signaling in the fight against obesity and insulin resistance, as well as in the promotion of adaptive thermogenesis.
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Affiliation(s)
- Roberto Coccurello
- Institute for Complex System (ISC), National Research Council (CNR), Rome, Italy
- Preclinical Neuroscience, European Center for Brain Research (CERC)/IRCCS Santa Lucia Foundation, Rome, Italy
| | - Cinzia Volonté
- Preclinical Neuroscience, European Center for Brain Research (CERC)/IRCCS Santa Lucia Foundation, Rome, Italy
- Institute for Systems Analysis and Computer Science, National Research Council (CNR), Rome, Italy
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Tozzi M, Hansen JB, Novak I. Pannexin-1 mediated ATP release in adipocytes is sensitive to glucose and insulin and modulates lipolysis and macrophage migration. Acta Physiol (Oxf) 2020; 228:e13360. [PMID: 31400255 DOI: 10.1111/apha.13360] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 07/29/2019] [Accepted: 08/07/2019] [Indexed: 12/15/2022]
Abstract
AIM Extracellular ATP signalling is involved in many physiological and pathophysiological processes in several tissues, including adipose tissue. Adipocytes have crucial functions in lipid and glucose metabolism and they express purinergic receptors. However, the sources of extracellular ATP in adipose tissue are not well characterized. In the present study, we investigated the mechanism and regulation of ATP release in white adipocytes, and evaluated the role of extracellular ATP as potential autocrine and paracrine signal. METHODS Online ATP release was monitored in C3H10T1/2 cells and freshly isolated murine adipocytes. The ATP release mechanism and its regulation were tested in cells exposed to adrenergic agonists, insulin, glucose load and pharmacological inhibitors. Cell metabolism was monitored using Seahorse respirometry and expression analysis of pannexin-1 was performed on pre- and mature adipocytes. The ATP signalling was evaluated in live cell imaging (Ca2+ , pore formation), glycerol release and its effect on macrophages was tested in co-culture and migration assays. RESULTS Here, we show that upon adrenergic stimulation white murine adipocytes release ATP through the pannexin-1 pore that is regulated by a cAMP-PKA-dependent pathway. The ATP release correlates with increased cell metabolism and is sensitive to glucose. Extracellular ATP induces Ca2+ signalling and lipolysis in adipocytes and promotes macrophage migration. Importantly, ATP release is markedly inhibited by insulin, which operates via the activation of phosphodiesterase 3. CONCLUSIONS Our findings reveal an insulin-pannexin-1-purinergic signalling crosstalk in adipose tissue and we propose that deregulation of this signalling may contribute to adipose tissue inflammation and type 2 diabetes.
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Affiliation(s)
- Marco Tozzi
- Section for Cell Biology and Physiology, Department of Biology University of Copenhagen Copenhagen Denmark
| | - Jacob B. Hansen
- Section for Cell Biology and Physiology, Department of Biology University of Copenhagen Copenhagen Denmark
| | - Ivana Novak
- Section for Cell Biology and Physiology, Department of Biology University of Copenhagen Copenhagen Denmark
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Role of the P2X7 receptor in the pathogenesis of type 2 diabetes and its microvascular complications. Curr Opin Pharmacol 2019; 47:75-81. [PMID: 30954933 DOI: 10.1016/j.coph.2019.02.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 02/19/2019] [Accepted: 02/21/2019] [Indexed: 12/16/2022]
Abstract
P2X7 receptors can be found in many tissues and organs, where they mediate several biological functions. This review summarizes the current knowledge about the role of this receptor in the pathogenesis of type 2 diabetes, in which the key clinical features are impaired insulin secretion and sensitivity, hyperglycemia, coexistence of other cardiovascular risk factors such as dyslipidemia and hypertension, and subclinical inflammation. The receptor modulates crucial pathways in the pancreatic islets (where it can either exert a trophic or detrimental action on β cells), and in the liver, in the adipose tissue and in the skeletal muscle, which are main sites of insulin resistance. P2X7 receptors also modulate a series of inflammatory responses that participate in the development of the microvascular complications of the disease. Potent and selective P2X7R blockers are available to be tested in Phase I/II clinical studies for the treatment of several chronic diseases, and it might be worthwhile to consider inclusion of patients with type 2 diabetes and its complications.
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P2Y 2 and P2Y 6 receptor activation elicits intracellular calcium responses in human adipose-derived mesenchymal stromal cells. Purinergic Signal 2018; 14:371-384. [PMID: 30088129 PMCID: PMC6298923 DOI: 10.1007/s11302-018-9618-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 06/29/2018] [Indexed: 02/07/2023] Open
Abstract
Adipose tissue contains self-renewing multipotent cells termed mesenchymal stromal cells. In situ, these cells serve to expand adipose tissue by adipogenesis, but their multipotency has gained interest for use in tissue regeneration. Little is known regarding the repertoire of receptors expressed by adipose-derived mesenchymal stromal cells (AD-MSCs). The purpose of this study was to undertake a comprehensive analysis of purinergic receptor expression. Mesenchymal stromal cells were isolated from human subcutaneous adipose tissue and confirmed by flow cytometry. The expression profile of purinergic receptors was determined by quantitative real-time PCR and immunocytochemistry. The molecular basis for adenine and uracil nucleotide-evoked intracellular calcium responses was determined using Fura-2 measurements. All the known subtypes of P2X and P2Y receptors, excluding P2X2, P2X3 and P2Y12 receptors, were detected at the mRNA and protein level. ATP, ADP and UTP elicited concentration-dependent calcium responses in mesenchymal cells (N = 7–9 donors), with a potency ranking ADP (EC50 1.3 ± 1.0 μM) > ATP (EC50 2.2 ± 1.1 μM) = UTP (3.2 ± 2.8 μM). Cells were unresponsive to UDP (< 30 μM) and UDP-glucose (< 30 μM). ATP responses were attenuated by selective P2Y2 receptor antagonism (AR-C118925XX; IC50 1.1 ± 0.8 μM, 73.0 ± 8.5% max inhibition; N = 7 donors), and UTP responses were abolished. ADP responses were attenuated by the selective P2Y6 receptor antagonist, MRS2587 (IC50 437 ± 133nM, 81.0 ± 8.4% max inhibition; N = 6 donors). These data demonstrate that adenine and uracil nucleotides elicit intracellular calcium responses in human AD-MSCs with a predominant role for P2Y2 and P2Y6 receptor activation. This study furthers understanding about how human adipose-derived mesenchymal stromal cells can respond to external signalling cues.
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Novak I, Solini A. P2X receptor-ion channels in the inflammatory response in adipose tissue and pancreas — potential triggers in onset of type 2 diabetes? Curr Opin Immunol 2018. [DOI: 10.1016/j.coi.2018.02.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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20
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Burnstock G, Gentile D. The involvement of purinergic signalling in obesity. Purinergic Signal 2018; 14:97-108. [PMID: 29619754 PMCID: PMC5940632 DOI: 10.1007/s11302-018-9605-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 03/16/2018] [Indexed: 12/18/2022] Open
Abstract
Obesity is a growing worldwide health problem, with an alarming increasing prevalence in developed countries, caused by a dysregulation of energy balance. Currently, no wholly successful pharmacological treatments are available for obesity and related adverse consequences. In recent years, hints obtained from several experimental animal models support the notion that purinergic signalling, acting through ATP-gated ion channels (P2X), G protein-coupled receptors (P2Y) and adenosine receptors (P1), is involved in obesity, both at peripheral and central levels. This review has drawn together, for the first time, the evidence for a promising, much needed novel therapeutic purinergic signalling approach for the treatment of obesity with a 'proof of concept' that hopefully could lead to further investigations and clinical trials for the management of obesity.
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Affiliation(s)
- Geoffrey Burnstock
- Department of Pharmacology and Therapeutics, The University of Melbourne, Parkville, Melbourne, Victoria, 3010, Australia.
- The Florey Institute of Neuroscience and Mental Health, Parkville, Melbourne, Australia.
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF, UK.
| | - Daniela Gentile
- Department of Clinical and Experimental Medicine, University of Pisa, Via Roma 55, 56126, Pisa, Italy
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Loss of P2X7 receptor function dampens whole body energy expenditure and fatty acid oxidation. Purinergic Signal 2018; 14:299-305. [PMID: 29754194 DOI: 10.1007/s11302-018-9610-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 05/01/2018] [Indexed: 12/24/2022] Open
Abstract
The established role of ATP-responsive P2X7 receptor in inflammatory, neurodegenerative, and immune diseases is now expanding to include several aspects of metabolic dysregulation. Indeed, P2X7 receptors are involved in β cell function, insulin secretion, and liability to diabetes, and loss of P2X7 function may increase the risk of hepatic steatosis and disrupt adipogenesis. Recently, body weight gain, abnormal lipid accumulation, adipocyte hyperplasia, increased fat mass, and ectopic fat distribution have been found in P2X7 KO mice. Here, we hypothesized that such clinical picture of dysregulated lipid metabolism might be the result of altered in vivo energy metabolism. By indirect calorimetry, we assessed 24 h of energy expenditure (EE) and respiratory exchange ratio (RER) as quotient of carbohydrate to fat oxidation in P2X7 KO mice. Moreover, we assessed the same parameters in aged-matched WT counterparts that underwent a 7-day treatment with the P2X7 antagonist A804598. We found that loss of P2X7 function elicits a severe decrease of EE that was less pronounced in A804598-treated mice. In parallel, P2X7KO mice show a drastic increase of RER, thus indicating the occurrence of a greater ratio of carbohydrate to fat oxidation. Decreased EE and fat oxidation is predictive of body weight gain, which was here confirmed. Taken together, our data provide evidence that P2X7 loss of function produces defective energy homeostasis that, together with disrupted adipogenesis, might help to explain accumulation of adipose tissue and contribute to disclose the potential role of P2X7 in metabolic diseases.
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22
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Tozzi M, Novak I. Purinergic Receptors in Adipose Tissue As Potential Targets in Metabolic Disorders. Front Pharmacol 2017; 8:878. [PMID: 29249968 PMCID: PMC5715378 DOI: 10.3389/fphar.2017.00878] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 11/13/2017] [Indexed: 01/04/2023] Open
Abstract
Extracellular nucleosides and nucleotides, such as adenosine and adenosine triphosphate (ATP), are involved in many physiological and pathological processes in adipose tissue (AT). It is becoming accepted that, in addition to the well-established sympathetic and hormonal system, purinergic receptors contribute significantly to regulation of adipocyte functions. Several receptor subtypes for both adenosine (P1) and ATP (P2X and P2Y) have been characterized in white adipocytes (WA) and brown adipocytes (BA). The effects mediated by adenosine and ATP on adipocytes are multiple and often differing, depending on specific receptors activated. Using a variety of agonists, antagonists and transgenic animals it has been demonstrated that adenosine and P2 receptors are involved in lipolysis, lipogenesis, adipokines secretion, glucose uptake, adipogenesis, cell proliferation, inflammation, and other processes. Given their central role in regulating many AT functions, purinergic receptors are considered potential therapeutic targets in different pathological conditions, such as obesity and type-2 diabetes. To achieve this goal, specific and potent P1 and P2 receptors activators and inhibitors are being developed and show promising results. However, more insight is needed into the function of P2 receptors in brown and beige adipocytes and their potential role in thermogenesis. This review aims at summarizing current knowledge on the patho-/physiological role of P1, P2X, and P2Y receptors in WA and BA and their potential exploitation for pharmacological intervention. Furthermore, we analyze impact of purinergic signaling in AT - in health and metabolic diseases.
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Affiliation(s)
- Marco Tozzi
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Ivana Novak
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
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Purinergic P2X7 receptor functional genetic polymorphisms are associated with the susceptibility to obesity in Chinese postmenopausal women. Menopause 2017; 25:329-335. [PMID: 29088017 DOI: 10.1097/gme.0000000000000991] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
OBJECTIVE We conducted a case-control study to investigate the associations of functional single-nucleotide polymorphisms in the purinergic P2X7 receptor (P2X7R) gene (rs2393799, rs7958311, rs1718119, rs2230911, and rs3751143) with obesity and overweight in a population of Chinese postmenopausal women. METHODS Our study included 180 obese women, 179 overweight women, and 204 controls. All participants were genotyped at the P2X7R rs2393799, rs7958311, rs1718119, rs2230911, and rs3751143 loci via allele-specific polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism procedures. The relationships between P2X7R genetic polymorphisms and their associated haplotypes with obesity (body mass index [BMI] ≥30 kg/m] and overweight (25 kg/m ≤ BMI < 30 kg/m) were evaluated. RESULTS Our results showed that P2X7R rs2230911G and rs1718119A were associated with an increased risk of obesity; in particular, both carriers of the rs2230911G allele and GG/(CG + GG) genotypes (G vs C, P < 0.001, odds ratio [OR] 2.87, 95% confidence interval [CI] 1.98-4.16; GG vs CC, P < 0.001, OR 8.76, 95% CI 3.29-23.35; CG + GG vs CC, P < 0.001, OR 2.54, 95% CI 1.63-3.95) and carriers of the rs17181191A allele and GA/(GA + AA) genotypes (A vs G, P < 0.001, OR 2.97, 95% CI 1.86-4.74; GA vs GG, P = 0.001, OR 2.72, 95% CI 1.55-4.79; GA + AA vs GG, P < 0.001, OR 3.05, 95% CI 1.79-5.19) were at a higher risk of obesity. No association with obesity or overweight was observed for the other three P2X7R polymorphisms (rs2393799, rs7958311, and rs3751143). Haplotype analysis indicated that P2X7R rs1718119A-rs2230911G-rs3751143C appeared to be a significant risk haplotype with obesity (P = 0.0005, OR 2.37, 95% CI 1.45-3.90). CONCLUSIONS P2X7R functional genetic polymorphisms and their estimated haplotypes are associated with obesity in Chinese postmenopausal women.
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Li W, Li G, Zhang Y, Wei S, Song M, Wang W, Yuan X, Wu H, Yang Y. Role of P2 × 7 receptor in the differentiation of bone marrow stromal cells into osteoblasts and adipocytes. Exp Cell Res 2015; 339:367-79. [PMID: 26481422 DOI: 10.1016/j.yexcr.2015.10.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 10/07/2015] [Accepted: 10/09/2015] [Indexed: 01/05/2023]
Abstract
Imbalance in osteogenesis and adipogenesis of bone marrow stromal cells is a crucial pathological process of osteoporosis. P2 × 7-deficient mice were previously shown to exhibit an osteopenic phenotype and abnormal fat distribution, leading us to hypothesize that P2 × 7R activation was involved in the differentiation of BMSCs. Consequently, we investigated the effect of P2 × 7R activation on osteogenic and adipogenic differentiation of BMSCs in vitro, and established an ovariectomized (OVX) osteoporosis model to test P2 × 7R activation on adipocytes formation, trabecular and cortical bone parameters in vivo. Our results showed that activation of P2 × 7R by BzATP resulted in increase in the gene expression of osteoblastic markers, the activity of alkaline phosphatase and bone mineralization, and decrease in the gene expression of adipogenic markers and the number of adipocytes generated by BMSCs. MicroCT analysis showed that BzATP treatment ameliorated the micro-architecture of trabecular bones in OVX mice, while cortical bone parameters were unaffected. H&E staining analysis showed that was increase in the volume of trabecular bone and number of trabecular bone, and decrease in bone marrow adipocytes in BzATP-treated OVX mice compared with OVX mice. Also, activation of P2 × 7R transduced to ERK1/2 and JNK signaling pathways. This transduction was prevented by BBG, U0126, and SP600125. U0126 and SP600125 prevented BzATP-induced up-regulation of osteogenic-related genes expression and down-regulation of adipogenic-related genes expression. These data suggest that BzATP activates the differentiation of BMSCs into osteoblasts but not adipocytes by stimulating ERK1/2 and JNK signaling pathways in a P2 × 7R-dependent way.
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Affiliation(s)
- Wenkai Li
- Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Jiefang Avenue 1095, Wuhan 430030, China
| | - Guizhen Li
- Department of Orthopedics, Enshi Center Hospital, Enshi 445000, China
| | - Yingchi Zhang
- Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Jiefang Avenue 1095, Wuhan 430030, China
| | - Sheng Wei
- Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Jiefang Avenue 1095, Wuhan 430030, China
| | - Mingyu Song
- Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Jiefang Avenue 1095, Wuhan 430030, China
| | - Wei Wang
- Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Jiefang Avenue 1095, Wuhan 430030, China
| | - Xuefeng Yuan
- Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Jiefang Avenue 1095, Wuhan 430030, China
| | - Hua Wu
- Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Jiefang Avenue 1095, Wuhan 430030, China.
| | - Yong Yang
- Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Jiefang Avenue 1095, Wuhan 430030, China.
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Lajdova I, Spustova V, Oksa A, Kaderjakova Z, Chorvat D, Morvova M, Sikurova L, Marcek Chorvatova A. The Impact of Vitamin D3 Supplementation on Mechanisms of Cell Calcium Signaling in Chronic Kidney Disease. BIOMED RESEARCH INTERNATIONAL 2015; 2015:807673. [PMID: 26064953 PMCID: PMC4434177 DOI: 10.1155/2015/807673] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 12/19/2014] [Indexed: 01/24/2023]
Abstract
Intracellular calcium concentration in peripheral blood mononuclear cells (PBMCs) of patients with chronic kidney disease (CKD) is significantly increased, and the regulatory mechanisms maintaining cellular calcium homeostasis are impaired. The purpose of this study was to examine the effect of vitamin D3 on predominant regulatory mechanisms of cell calcium homeostasis. The study involved 16 CKD stages 2-3 patients with vitamin D deficiency treated with cholecalciferol 7000-14000 IU/week for 6 months. The regulatory mechanisms of calcium signaling were studied in PBMCs and red blood cells. After vitamin D3 supplementation, serum concentration of 25(OH)D3 increased (P < 0.001) and [Ca(2+)]i decreased (P < 0.001). The differences in [Ca(2+)]i were inversely related to differences in 25(OH)D3 concentration (P < 0.01). Vitamin D3 supplementation decreased the calcium entry through calcium release activated calcium (CRAC) channels and purinergic P2X7 channels. The function of P2X7 receptors was changed in comparison with their baseline status, and the expression of these receptors was reduced. There was no effect of vitamin D3 on P2X7 pores and activity of plasma membrane Ca(2+)-ATPases. Vitamin D3 supplementation had a beneficial effect on [Ca(2+)]i decreasing calcium entry via CRAC and P2X7 channels and reducing P2X7 receptors expression.
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Affiliation(s)
- Ingrid Lajdova
- Department of Clinical and Experimental Pharmacology, Faculty of Medicine, Slovak Medical University, 833 03 Bratislava, Slovakia
| | - Viera Spustova
- Department of Clinical and Experimental Pharmacology, Faculty of Medicine, Slovak Medical University, 833 03 Bratislava, Slovakia
| | - Adrian Oksa
- Department of Clinical and Experimental Pharmacology, Faculty of Medicine, Slovak Medical University, 833 03 Bratislava, Slovakia
| | - Zuzana Kaderjakova
- Department of Nuclear Physics and Biophysics, Faculty of Mathematics, Physics and Informatics, Comenius University, 833 03 Bratislava, Slovakia
| | - Dusan Chorvat
- Department of Biophotonics, International Laser Centre, 833 03 Bratislava, Slovakia
| | - Marcela Morvova
- Department of Nuclear Physics and Biophysics, Faculty of Mathematics, Physics and Informatics, Comenius University, 833 03 Bratislava, Slovakia
| | - Libusa Sikurova
- Department of Nuclear Physics and Biophysics, Faculty of Mathematics, Physics and Informatics, Comenius University, 833 03 Bratislava, Slovakia
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Bełtowski J, Guranowski A, Jamroz-Wiśniewska A, Wolski A, Hałas K. Hydrogen-sulfide-mediated vasodilatory effect of nucleoside 5'-monophosphorothioates in perivascular adipose tissue. Can J Physiol Pharmacol 2015; 93:585-95. [PMID: 26120822 DOI: 10.1139/cjpp-2014-0543] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Hydrogen sulfide (H2S) is synthesized in perivascular adipose tissue (PVAT) and induces vasorelaxation. We examined whether the sulfur-containing AMP and GMP analogs AMPS and GMPS can serve as the H2S donors in PVAT. H2S production by isolated rat periaortic adipose tissue (PAT) was measured with a polarographic sensor. In addition, phenylephrine-induced contractility of aortic rings with (+) or without (-) PAT was examined. Isolated PAT produced H2S from AMPS or GMPS in the presence of the P2X7 receptor agonist BzATP. Phenylephrine-induced contractility of PAT(+) rings was lower than of PAT(-) rings. AMPS or GMPS had no effect on the contractility of PAT(-) rings, but used together with BzATP reduced the contractility of PAT(+) rings when endogenous H2S production was inhibited with propargylglycine. A high-fat diet reduced endogenous H2S production by PAT. Interestingly, AMPS and GMPS were converted to H2S by PAT of obese rats, and reduced contractility of PAT(+) aortic rings isolated from these animals even in the absence of BzATP. We conclude that (i) AMPS and GMPS can be hydrolyzed to H2S by PAT when P2X7 receptors are activated, (ii) a high-fat diet impairs endogenous H2S production by PAT, (iii) AMPS and GMPS restore the anticontractile effects of PAT in obese animals without P2X7 stimulation.
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Affiliation(s)
- Jerzy Bełtowski
- a Department of Pathophysiology, Medical University, ul. Jaczewskiego 8, 20-090 Lublin, Poland
| | - Andrzej Guranowski
- b Department of Biochemistry and Biotechnology, Poznań University of Life Sciences, Poznań, Poland
| | | | - Andrzej Wolski
- d Department of Interventional Radiology and Neuroradiology, Medical University, Lublin, Poland
| | - Krzysztof Hałas
- d Department of Interventional Radiology and Neuroradiology, Medical University, Lublin, Poland
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Pandolfi J, Ferraro A, Lerner M, Serrano JR, Dueck A, Fainboim L, Arruvito L. Purinergic signaling modulates human visceral adipose inflammatory responses: implications in metabolically unhealthy obesity. J Leukoc Biol 2015; 97:941-949. [PMID: 25717146 DOI: 10.1189/jlb.3a1214-626r] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Revised: 01/28/2015] [Accepted: 01/30/2015] [Indexed: 12/18/2022] Open
Abstract
Obesity is accompanied by chronic inflammation of VAT, which promotes metabolic changes, and purinergic signaling has a key role in a wide range of inflammatory diseases. Therefore, we addressed whether fat inflammation could be differentially modulated by this signaling pathway in the MUO and in individuals who remain MHO. Our results show that the necrotized VAT of both groups released greater levels of ATP compared with lean donors. Interestingly, MUO tissue SVCs showed up-regulation and engagement of the purinergic P2X7R. The extracellular ATP concentration is regulated by an enzymatic process, in which CD39 converts ATP and ADP into AMP, and CD73 converts AMP into adenosine. In VAT, the CD73 ectoenzyme was widely distributed in immune and nonimmune cells, whereas CD39 expression was restricted to immune CD45PAN+ SVCs. Although the MUO group expressed the highest levels of both ectoenzymes, no difference in ATP hydrolysis capacity was found between the groups. As expected, MUO exhibited the highest NLRP3 inflammasome expression and IL-1β production. MUO SVCs also displayed up-regulation of the A2AR, allowing extracellular adenosine to increase IL-1β local secretion. Additionally, we demonstrate that metabolic parameters and BMI are positively correlated with purinergic components in VAT. These findings indicate that purinergic signaling is a novel mechanism involved in the chronic inflammation of VAT underlying the metabolic changes in obesity. Finally, our study reveals a proinflammatory role for adenosine in sustaining IL-1β production in this tissue.
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Affiliation(s)
- J Pandolfi
- *Instituto de Inmunología, Genética y Metabolismo, and División Cirugía Gastroenterológica, Hospital de Clínicas "José de San Martín," Universidad de Buenos Aires, Argentina
| | - A Ferraro
- *Instituto de Inmunología, Genética y Metabolismo, and División Cirugía Gastroenterológica, Hospital de Clínicas "José de San Martín," Universidad de Buenos Aires, Argentina
| | - M Lerner
- *Instituto de Inmunología, Genética y Metabolismo, and División Cirugía Gastroenterológica, Hospital de Clínicas "José de San Martín," Universidad de Buenos Aires, Argentina
| | - J R Serrano
- *Instituto de Inmunología, Genética y Metabolismo, and División Cirugía Gastroenterológica, Hospital de Clínicas "José de San Martín," Universidad de Buenos Aires, Argentina
| | - A Dueck
- *Instituto de Inmunología, Genética y Metabolismo, and División Cirugía Gastroenterológica, Hospital de Clínicas "José de San Martín," Universidad de Buenos Aires, Argentina
| | - L Fainboim
- *Instituto de Inmunología, Genética y Metabolismo, and División Cirugía Gastroenterológica, Hospital de Clínicas "José de San Martín," Universidad de Buenos Aires, Argentina
| | - L Arruvito
- *Instituto de Inmunología, Genética y Metabolismo, and División Cirugía Gastroenterológica, Hospital de Clínicas "José de San Martín," Universidad de Buenos Aires, Argentina
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Kaebisch C, Schipper D, Babczyk P, Tobiasch E. The role of purinergic receptors in stem cell differentiation. Comput Struct Biotechnol J 2014; 13:75-84. [PMID: 26900431 PMCID: PMC4720018 DOI: 10.1016/j.csbj.2014.11.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Revised: 10/31/2014] [Accepted: 11/03/2014] [Indexed: 12/20/2022] Open
Abstract
A major challenge modern society has to face is the increasing need for tissue regeneration due to degenerative diseases or tumors, but also accidents or warlike conflicts. There is great hope that stem cell-based therapies might improve current treatments of cardiovascular diseases, osteochondral defects or nerve injury due to the unique properties of stem cells such as their self-renewal and differentiation potential. Since embryonic stem cells raise severe ethical concerns and are prone to teratoma formation, adult stem cells are still in the focus of research. Emphasis is placed on cellular signaling within these cells and in between them for a better understanding of the complex processes regulating stem cell fate. One of the oldest signaling systems is based on nucleotides as ligands for purinergic receptors playing an important role in a huge variety of cellular processes such as proliferation, migration and differentiation. Besides their natural ligands, several artificial agonists and antagonists have been identified for P1 and P2 receptors and are already used as drugs. This review outlines purinergic receptor expression and signaling in stem cells metabolism. We will briefly describe current findings in embryonic and induced pluripotent stem cells as well as in cancer-, hematopoietic-, and neural crest-derived stem cells. The major focus will be placed on recent findings of purinergic signaling in mesenchymal stem cells addressed in in vitro and in vivo studies, since stem cell fate might be manipulated by this system guiding differentiation towards the desired lineage in the future.
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Affiliation(s)
| | | | | | - Edda Tobiasch
- Department of Natural Sciences, Bonn-Rhine-Sieg University of Applied Sciences, Von-Liebig-Str. 20, 53359 Rheinbach, Germany
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Adamson SE, Leitinger N. The role of pannexin1 in the induction and resolution of inflammation. FEBS Lett 2014; 588:1416-22. [PMID: 24642372 DOI: 10.1016/j.febslet.2014.03.009] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 03/03/2014] [Accepted: 03/03/2014] [Indexed: 02/06/2023]
Abstract
Extracellular ATP is an important signaling molecule throughout the inflammatory cascade, serving as a danger signal that causes activation of the inflammasome, enhancement of immune cell infiltration, and fine-tuning of several signaling cascades including those important for the resolution of inflammation. Recent studies demonstrated that ATP can be released from cells in a controlled manner through pannexin (Panx) channels. Panx1-mediated ATP release is involved in inflammasome activation and neutrophil/macrophage chemotaxis, activation of T cells, and a role for Panx1 in inducing and propagating inflammation has been demonstrated in various organs, including lung and the central and peripheral nervous system. The recognition and clearance of dying cells and debris from focal points of inflammation is critical in the resolution of inflammation, and Panx1-mediated ATP release from dying cells has been shown to recruit phagocytes. Moreover, extracellular ATP can be broken down by ectonucleotidases into ADP, AMP, and adenosine, which is critical in the resolution of inflammation. Together, Panx1, ATP, purinergic receptors, and ectonucleotidases contribute to important feedback loops during the inflammatory response, and thus represent promising candidates for new therapies.
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Burnstock G. Purinergic signalling in endocrine organs. Purinergic Signal 2014; 10:189-231. [PMID: 24265070 PMCID: PMC3944044 DOI: 10.1007/s11302-013-9396-x] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 10/24/2013] [Indexed: 01/08/2023] Open
Abstract
There is widespread involvement of purinergic signalling in endocrine biology. Pituitary cells express P1, P2X and P2Y receptor subtypes to mediate hormone release. Adenosine 5'-triphosphate (ATP) regulates insulin release in the pancreas and is involved in the secretion of thyroid hormones. ATP plays a major role in the synthesis, storage and release of catecholamines from the adrenal gland. In the ovary purinoceptors mediate gonadotrophin-induced progesterone secretion, while in the testes, both Sertoli and Leydig cells express purinoceptors that mediate secretion of oestradiol and testosterone, respectively. ATP released as a cotransmitter with noradrenaline is involved in activities of the pineal gland and in the neuroendocrine control of the thymus. In the hypothalamus, ATP and adenosine stimulate or modulate the release of luteinising hormone-releasing hormone, as well as arginine-vasopressin and oxytocin. Functionally active P2X and P2Y receptors have been identified on human placental syncytiotrophoblast cells and on neuroendocrine cells in the lung, skin, prostate and intestine. Adipocytes have been recognised recently to have endocrine function involving purinoceptors.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF, UK,
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Bulloch JM, Daly CJ. Autonomic nerves and perivascular fat: interactive mechanisms. Pharmacol Ther 2014; 143:61-73. [PMID: 24560685 DOI: 10.1016/j.pharmthera.2014.02.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 02/03/2014] [Indexed: 12/31/2022]
Abstract
The evidence describing the autonomic innervation of body fat is reviewed with a particular focus on the role of the sympathetic neurotransmitters. In compiling the evidence, a strong case emerges for the interaction between autonomic nerves and perivascular adipose tissue (PVAT). Adipocytes have been shown to express receptors for neurotransmitters released from nearby sympathetic varicosities such as adrenoceptors (ARs), purinoceptors and receptors for neuropeptide Y (NPY). Noradrenaline can modulate both lipolysis (via α2- and β3-ARs) and lipogenesis (via α1- and β3-ARs). ATP can inhibit lipolysis (via P1 purinoceptors) or stimulate lipolysis (via P2y purinoceptors). NPY, which can be produced by adipocytes and sympathetic nerves, inhibits lipolysis. Thus the sympathetic triad of transmitters can influence adipocyte free fatty acid (FFA) content. Substance P (SP) released from sensory nerves has also been shown to promote lipolysis. Therefore, we propose a mechanism whereby sympathetic neurotransmission can simultaneously activate smooth muscle cells in the tunica media to cause vasoconstriction and alter FFA content and release from adjacent adipocytes in PVAT. The released FFA can influence endothelial function. Adipocytes also release a range of vasoactive substances, both relaxing and contractile factors, including adiponectin and reactive oxygen species. The action of adipokines (such as adiponectin) and reactive oxygen species (ROS) on cells of the vascular adventitia and nerves has yet to be fully elucidated. We hypothesise a strong link between PVAT and autonomic fibres and suggest that this poorly understood relationship is extremely important for normal vascular function and warrants a detailed study.
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Affiliation(s)
- Janette M Bulloch
- School of Science, University of the West of Scotland, Hamilton ML3 0JB, Scotland.
| | - Craig J Daly
- School of Life Sciences, University of Glasgow, Glasgow G128QQ, Scotland.
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Rossi C, Santini E, Chiarugi M, Salvati A, Comassi M, Vitolo E, Madec S, Solini A. The complex P2X7 receptor/inflammasome in perivascular fat tissue of heavy smokers. Eur J Clin Invest 2014; 44:295-302. [PMID: 24372548 DOI: 10.1111/eci.12232] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 12/17/2013] [Indexed: 12/18/2022]
Abstract
OBJECTIVE Smoking is a recognized cardiovascular risk factor. Perivascular visceral adipose tissue (PVAT) is a source of inflammatory molecules, thus contributing to atherosclerosis progression. The P2X7 receptor (P2X7 R)-inflammasome complex, crucial in determining IL-1β and IL-18 release, participates in this scenario. We evaluated whether smoking might affect the PVAT inflammatory phenotype and explored the putative role of the axis P2X7 R-inflammasome in this picture. SUBJECTS AND METHODS TNFα, IL-6, RBP4, MCP-1, as well as P2X7 R and inflammasome components NLRP3, ASC, caspase-1 and IL-1β and IL-18 expression was determined in adipocytes isolated by PVAT of healthy smokers (Smok) and nonsmokers (No-Smok) subjects. Plasma and culture medium levels of these cytokines were also determined. RESULTS Perivascular adipose tissue of Smok had a higher expression of P2X7 R and inflammasome components; via P2X7 R activation, it released more IL-1β and IL-18, whose serum levels were also higher in Smok than in No-Smok. Linear correlations of NLRP3 with P2X7 R and IL-18 expression and release emerged. Smok also had a higher PVAT expression of the chemotactic factor MCP-1. However, no difference was observed in the PVAT expression of genes more strictly related to insulin resistance, like TNFα, RBP4, IL-6; this was coupled with similar plasma levels of TNFα and RBP4 in the two groups. CONCLUSION Smoking contributes to the pro-inflammatory status of the PVAT by enhancing expression and activity of the P2X7 R-inflammasome complex; the effect on adipocytokines more related to insulin resistance and metabolic abnormalities appears trivial.
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Affiliation(s)
- Chiara Rossi
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
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P2X7 receptor polymorphisms do not influence endothelial function and vascular tone in neo-diagnosed, treatment-naive essential hypertensive patients. J Hypertens 2013; 31:2362-9. [DOI: 10.1097/hjh.0b013e3283653ff5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Loss of P2X7 nucleotide receptor function leads to abnormal fat distribution in mice. Purinergic Signal 2013; 10:291-304. [PMID: 24222214 DOI: 10.1007/s11302-013-9388-x] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 09/10/2013] [Indexed: 12/26/2022] Open
Abstract
The P2X7 receptor is an ATP-gated cation channel expressed by a number of cell types. We have shown previously that disruption of P2X7 receptor function results in downregulation of osteogenic markers and upregulation of adipogenic markers in calvarial cell cultures. In the present study, we assessed whether loss of P2X7 receptor function results in changes to adipocyte distribution and lipid accumulation in vivo. Male P2X7 loss-of-function (KO) mice exhibited significantly greater body weight and epididymal fat pad mass than wild-type (WT) mice at 9 months of age. Fat pad adipocytes did not differ in size, consistent with adipocyte hyperplasia rather than hypertrophy. Histological examination revealed ectopic lipid accumulation in the form of adipocytes and/or lipid droplets in several non-adipose tissues of older male KO mice (9-12 months of age). Ectopic lipid was observed in kidney, extraorbital lacrimal gland and pancreas, but not in liver, heart or skeletal muscle. Specifically, lacrimal gland and pancreas from 12-month-old male KO mice had greater numbers of adipocytes in perivascular, periductal and acinar regions. As well, lipid droplets accumulated in the renal tubular epithelium and lacrimal acinar cells. Blood plasma analyses revealed diminished total cholesterol levels in 9- and 12-month-old male KO mice compared with WT controls. Interestingly, no differences were observed in female mice. Moreover, there were no significant differences in food consumption between male KO and WT mice. Taken together, these data establish novel in vivo roles for the P2X7 receptor in regulating adipogenesis and lipid metabolism in an age- and sex-dependent manner.
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Baldini C, Rossi C, Ferro F, Santini E, Seccia V, Donati V, Solini A. The P2X7 receptor-inflammasome complex has a role in modulating the inflammatory response in primary Sjögren's syndrome. J Intern Med 2013; 274:480-9. [PMID: 23906036 DOI: 10.1111/joim.12115] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
OBJECTIVE Innate and adaptive immunity may contribute to gland dysfunction in patients with primary Sjögren's syndrome (pSS). The P2X7 receptor (P2X7 R)-NLRP3 inflammasome complex modulates the release of the inflammatory cytokines IL-1β and IL-18. The presence of P2X7 R in salivary glands suggests an interesting scenario for the initiation and amplification of the innate immune response in pSS. Therefore, the aim of this study was to assess the role of the P2X7 R-NLRP3 inflammasome in pSS. SUBJECTS AND METHODS Twenty-one consecutive patients with pSS according to the American-European Consensus Group criteria and 15 patients with sicca syndrome (i.e. without Sjögren's syndrome, non-SS) were enrolled in this study, together with six control (CTL) subjects. Expression of the P2X7R-NLRP3 platform and IL-18 was determined by real-time PCR and western blotting in gland specimens and peripheral lymphomonocytes; data were related to patients\x92 clinical, serological and histopathological characteristics. The presence of IL-18 was determined in gland and saliva samples. RESULTS P2X7 R expression was significantly higher in salivary glands from individuals with pSS than in those from non-SS and CTL subjects. Accordingly, the gene expression levels of the inflammasome components NLRP3, ASC and caspase-1 were significantly higher in pSS gland specimens, and this was paralleled by an increased expression of mature IL-18 in pSS saliva samples. The expression of both the P2X7 R and the inflammasome components was a marker of disease-related glandular involvement, being increased in patients with anti-Ro/SSA positivity and correlated with focus score. CONCLUSION The results of this study suggest an involvement of the P2X7 R-inflammasome-caspase-1-IL-18 axis in the development of pSS exocrinopathy. This finding provides the basis for studying the complex mechanisms underlying pSS, as well as for developing novel potential therapeutic strategies.
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Affiliation(s)
- C Baldini
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
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Abstract
The pancreas is an organ with a central role in nutrient breakdown, nutrient sensing and release of hormones regulating whole body nutrient homeostasis. In diabetes mellitus, the balance is broken-cells can be starving in the midst of plenty. There are indications that the incidence of diabetes type 1 and 2, and possibly pancreatogenic diabetes, is rising globally. Events leading to insulin secretion and action are complex, but there is emerging evidence that intracellular nucleotides and nucleotides are not only important as intracellular energy molecules but also as extracellular signalling molecules in purinergic signalling cascades. This signalling takes place at the level of the pancreas, where the close apposition of various cells-endocrine, exocrine, stromal and immune cells-contributes to the integrated function. Following an introduction to diabetes, the pancreas and purinergic signalling, we will focus on the role of purinergic signalling and its changes associated with diabetes in the pancreas and selected tissues/organ systems affected by hyperglycaemia and other stress molecules of diabetes. Since this is the first review of this kind, a comprehensive historical angle is taken, and common and divergent roles of receptors for nucleotides and nucleosides in different organ systems will be given. This integrated picture will aid our understanding of the challenges of the potential and currently used drugs targeted to specific organ/cells or disorders associated with diabetes.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF UK
- Department of Pharmacology, Melbourne University, Melbourne, Australia
| | - Ivana Novak
- Molecular and Integrative Physiology, Department of Biology, University of Copenhagen, August Krogh Building, Universitetsparken 13, 2100 Copenhagen Ø, Denmark
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The NLRP3 Inflammasome as a novel player of the intercellular crosstalk in metabolic disorders. Mediators Inflamm 2013; 2013:678627. [PMID: 23843683 PMCID: PMC3697790 DOI: 10.1155/2013/678627] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 05/13/2013] [Accepted: 05/22/2013] [Indexed: 01/13/2023] Open
Abstract
The combination of obesity and type 2 diabetes is a serious health problem, which is projected to afflict 300 million people worldwide by 2020. Both clinical and translational laboratory studies have demonstrated that chronic inflammation is associated with obesity and obesity-related conditions such as insulin resistance. However, the precise etiopathogenetic mechanisms linking obesity to diabetes remain to be elucidated, and the pathways that mediate this phenomenon are not fully characterized. One of the most recently identified signaling pathways, whose activation seems to affect many metabolic disorders, is the “inflammasome,” a multiprotein complex composed of NLRP3 (nucleotide-binding domain and leucine-rich repeat protein 3), ASC (apoptosis-associated speck-like protein containing a CARD), and procaspase-1. NLRP3 inflammasome activation leads to the processing and secretion of the proinflammatory cytokines interleukin- (IL-) 1β and IL-18. The goal of this paper is to review new insights on the effects of the NLRP3 inflammasome activation in the complex mechanisms of crosstalk between different organs, for a better understanding of the role of chronic inflammation in metabolic disease pathogenesis. We will provide here a perspective on the current research on NLRP3 inflammasome, which may represent an innovative therapeutic target to reverse the detrimental metabolic consequences of the metabolic inflammation.
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Burghoff S, Flögel U, Bongardt S, Burkart V, Sell H, Tucci S, Ikels K, Eberhard D, Kern M, Klöting N, Eckel J, Schrader J. Deletion of CD73 promotes dyslipidemia and intramyocellular lipid accumulation in muscle of mice. Arch Physiol Biochem 2013; 119:39-51. [PMID: 23398498 DOI: 10.3109/13813455.2012.755547] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
CONTEXT CD73 converts extracellular AMP to adenosine which is well known to inhibit lipolysis. It is unknown, however, whether adenosine formed directly by CD73 is functionally relevant in this process. OBJECTIVE We therefore explored the effect of CD73-derived adenosine on body fat of aged mice. RESULTS In lean mice, extracellular adenosine formation by adipocytes is dependent on CD73. High fat diet down-regulates the expression of CD73 in wildtype mice similar to ob/ob mice. Transgenic mice chronically lacking CD73 (CD73(-/-)) gain significantly less body weight and show decreased superficial white fat content as well as increased serum free fatty acids and triglycerides. In addition, intramyocellular lipid levels are significantly increased. This phenotype is accompanied by an increase in blood glucose and serum insulin levels although insulin secretion and the level of insulin degrading enzyme are unaltered. Additionally, insulin-induced Akt phosphorylation is reduced in skeletal muscle of CD73(-/-) mice. CONCLUSION CD73-derived adenosine is functionally involved in body fat homeostasis.
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Affiliation(s)
- Sandra Burghoff
- Institute of Molecular Cardiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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Sparks DL, Chatterjee C. Purinergic signaling, dyslipidemia and inflammatory disease. Cell Physiol Biochem 2012; 30:1333-9. [PMID: 23095900 DOI: 10.1159/000343322] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/17/2012] [Indexed: 12/15/2022] Open
Abstract
Metabolic syndrome is a compound obesity disorder, wherein the abnormal metabolism of glucose and lipid is associated with the development of chronic inflammatory diseases. The prevalence of this disease is increasing in the developed world, but the causative linkage between these metabolic disorders has remained obscure. Metabolic disease may be associated with chronic nucleotide secretion, purinergic signaling and activation of inflammatory pathways. Purinergic signaling has been implicated in impaired glucose metabolism and inflammatory disease and may contribute to dyslipidemia. Our research shows that purinergic signaling disrupts hepatic lipoprotein metabolism by blocking insulin receptor signaling and by activating cellular autophagic pathways. Chronic stimulation of purinergic signaling may therefore be causative to glucose and lipid metabolic disorders and associated with the development of cardiovascular disease.
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Affiliation(s)
- Daniel L Sparks
- Atherosclerosis, Genetics and Cell Biology Group, University of Ottawa Heart Institute, Ottawa, ON, K1Y 4W7, Canada.
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Sun S, Xia S, Ji Y, Kersten S, Qi L. The ATP-P2X7 signaling axis is dispensable for obesity-associated inflammasome activation in adipose tissue. Diabetes 2012; 61:1471-8. [PMID: 22415881 PMCID: PMC3357307 DOI: 10.2337/db11-1389] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Inflammasome activation in adipose tissue has been implicated in obesity-associated insulin resistance and type 2 diabetes. However, when and how inflammasome is activated in adipose tissue remains speculative. Here we test the hypothesis that extracellular ATP, a potent stimulus of inflammasome in macrophages via purinergic receptor P2X, ligand-gated ion channel, 7 (P2X(7)), may play a role in inflammasome activation in adipose tissue in obesity. Our data show that inflammasome is activated in adipose tissue upon 8-week feeding of 60% high-fat diet (HFD), coinciding with the onset of hyperglycemia and hyperinsulinemia as well as the induction of P2X(7) in adipose tissue. Unexpectedly, P2X(7)-deficient animals on HFD exhibit no changes in metabolic phenotypes, inflammatory responses, or inflammasome activation when compared with the wild-type controls. Similar observations have been obtained in hematopoietic cell-specific P2X(7)-deficient animals generated by bone marrow transplantation. Thus, we conclude that inflammasome activation in adipose tissue in obesity coincides with the onset of hyperglycemia and hyperinsulinemia but, unexpectedly, is not mediated by the ATP-P2X(7) signaling axis. The nature of the inflammasome-activating danger signal(s) in adipose tissue in obesity remains to be characterized.
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Affiliation(s)
- Shengyi Sun
- Graduate Program in Biochemistry, Molecular, and Cell Biology, Cornell University, Ithaca, New York
| | - Sheng Xia
- Division of Nutritional Sciences, Cornell University, Ithaca, New York
| | - Yewei Ji
- Division of Nutritional Sciences, Cornell University, Ithaca, New York
| | - Sander Kersten
- Division of Nutritional Sciences, Cornell University, Ithaca, New York
- Nutrition, Metabolism, and Genomics Group, Division of Human Nutrition, Wageningen University, Wageningen, the Netherlands
| | - Ling Qi
- Graduate Program in Biochemistry, Molecular, and Cell Biology, Cornell University, Ithaca, New York
- Division of Nutritional Sciences, Cornell University, Ithaca, New York
- Corresponding author: Ling Qi,
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