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Tran KV, Donahue JK. Identifying the Role of Lipomatous Metaplasia in Ventricular Tachycardia Mechanism for Nonischemic Cardiomyopathy. JACC Clin Electrophysiol 2024; 10:1147-1149. [PMID: 38819349 DOI: 10.1016/j.jacep.2024.03.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Accepted: 03/12/2024] [Indexed: 06/01/2024]
Affiliation(s)
- Khanh-Van Tran
- Division of Cardiology, Department of Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA.
| | - J Kevin Donahue
- Division of Cardiology, Department of Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA.
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2
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Lee SY, Fontana F, Sugatani T, Portales Castillo I, Leanza G, Coler-Reilly A, Civitelli R. Connexin43 in mesenchymal lineage cells regulates body adiposity and energy metabolism in mice. JCI Insight 2024; 9:e170016. [PMID: 38349739 PMCID: PMC11063945 DOI: 10.1172/jci.insight.170016] [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: 02/23/2023] [Accepted: 02/08/2024] [Indexed: 02/27/2024] Open
Abstract
Connexin43 (Cx43) is the most abundant gap junction protein present in the mesenchymal lineage. In mature adipocytes, Cx43 mediates white adipose tissue (WAT) beiging in response to cold exposure and maintains the mitochondrial integrity of brown adipose tissue (BAT). We found that genetic deletion of Gja1 (Cx43 gene) in cells that give rise to chondro-osteogenic and adipogenic precursors driven by the Dermo1/Twist2 promoter led to lower body adiposity and partial protection against the weight gain and metabolic syndrome induced by a high-fat diet (HFD) in both sexes. These protective effects were related to increased locomotion, fuel utilization, energy expenditure, nonshivering thermogenesis, and better glucose tolerance in conditionally Gja1-ablated mice. Accordingly, Gja1-mutant mice exhibited reduced adipocyte hypertrophy, partially preserved insulin sensitivity, increased BAT lipolysis, and decreased whitening under HFD. This metabolic phenotype was not reproduced with more restricted Gja1 ablation in differentiated adipocytes, suggesting that Cx43 in adipocyte progenitors or other targeted cells restrains energy expenditures and promotes fat accumulation. These results reveal what we believe is a hitherto unknown action of Cx43 in adiposity, and offer a promising new pharmacologic target for improving metabolic balance in diabetes and obesity.
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Lee SY, Fontana F, Sugatani T, Castillo IP, Leanza G, Coler-Reilly A, Civitelli R. Connexin43 in mesenchymal lineage cells regulates body adiposity and energy metabolism in mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.05.574415. [PMID: 38260624 PMCID: PMC10802316 DOI: 10.1101/2024.01.05.574415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Connexin43 (Cx43) is the most abundant gap junction protein present in the mesenchymal lineage. In mature adipocytes, Cx43 mediates white adipose tissue (WAT) "beiging" in response to cold exposure and maintains the mitochondrial integrity of brown adipose tissue (BAT). We found that genetic deletion of Gja1 (Cx43 gene) in cells that give rise to chondro-osteogenic and adipogenic precursors driven by the Dermo1/Twist2 promoter leads to lower body adiposity and partial protection against the weight gain and metabolic syndrome induced by a high fat diet (HFD) in both sexes. These protective effects from obesogenic diet are related to increased locomotion, fuel utilization, energy expenditure, non-shivering thermogenesis, and better glucose tolerance in conditionally Gja1 ablated mice. Accordingly, Gja1 mutant mice exhibit reduced adipocyte hypertrophy, partially preserved insulin sensitivity, increased BAT lipolysis and decreased whitening under HFD. This metabolic phenotype is not reproduced with more restricted Gja1 ablation in differentiated adipocytes, suggesting that Cx43 has a hitherto unknown function in adipocyte progenitors or other targeted cells, resulting in restrained energy expenditures and fat accumulation. These results disclose an hitherto unknown action of Cx43 in adiposity, and offer a promising new pharmacologic target for improving metabolic balance in diabetes and obesity.
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Affiliation(s)
- Seung-Yon Lee
- Department of Medicine, Division of Bone and Mineral Diseases; Musculoskeletal Research Center; Washington University School of Medicine, St. Louis, MO. USA
| | - Francesca Fontana
- Department of Medicine, Division of Bone and Mineral Diseases; Musculoskeletal Research Center; Washington University School of Medicine, St. Louis, MO. USA
| | - Toshifumi Sugatani
- Department of Medicine, Division of Bone and Mineral Diseases; Musculoskeletal Research Center; Washington University School of Medicine, St. Louis, MO. USA
| | - Ignacio Portales Castillo
- Department of Medicine, Division of Bone and Mineral Diseases; Musculoskeletal Research Center; Washington University School of Medicine, St. Louis, MO. USA
| | - Giulia Leanza
- Department of Medicine, Division of Bone and Mineral Diseases; Musculoskeletal Research Center; Washington University School of Medicine, St. Louis, MO. USA
| | - Ariella Coler-Reilly
- Department of Medicine, Division of Bone and Mineral Diseases; Musculoskeletal Research Center; Washington University School of Medicine, St. Louis, MO. USA
| | - Roberto Civitelli
- Department of Medicine, Division of Bone and Mineral Diseases; Musculoskeletal Research Center; Washington University School of Medicine, St. Louis, MO. USA
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Simon-Chica A, Wülfers EM, Kohl P. Nonmyocytes as electrophysiological contributors to cardiac excitation and conduction. Am J Physiol Heart Circ Physiol 2023; 325:H475-H491. [PMID: 37417876 PMCID: PMC10538996 DOI: 10.1152/ajpheart.00184.2023] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 06/22/2023] [Accepted: 06/29/2023] [Indexed: 07/08/2023]
Abstract
Although cardiac action potential (AP) generation and propagation have traditionally been attributed exclusively to cardiomyocytes (CM), other cell types in the heart are also capable of forming electrically conducting junctions. Interactions between CM and nonmyocytes (NM) enable and modulate each other's activity. This review provides an overview of the current understanding of heterocellular electrical communication in the heart. Although cardiac fibroblasts were initially thought to be electrical insulators, recent studies have demonstrated that they form functional electrical connections with CM in situ. Other NM, such as macrophages, have also been recognized as contributing to cardiac electrophysiology and arrhythmogenesis. Novel experimental tools have enabled the investigation of cell-specific activity patterns in native cardiac tissue, which is expected to yield exciting new insights into the development of novel or improved diagnostic and therapeutic strategies.
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Affiliation(s)
- Ana Simon-Chica
- Novel Arrhythmogenic Mechanisms Program, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
| | - Eike M Wülfers
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg-Bad Krozingen, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Physics and Astronomy, Faculty of Sciences, Ghent University, Gent, Belgium
| | - Peter Kohl
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg-Bad Krozingen, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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Güiza J, Solís F, Valenzuela B, Arancibia D, Zamorano P, González J, Saavedra J, Neely A, Salgado M, Martínez AD, Sáez JC, Vega JL. Unnexin is a protein subunit of a large-pore channel expressed by unicellular organisms. Proc Natl Acad Sci U S A 2023; 120:e2307898120. [PMID: 37487087 PMCID: PMC10400985 DOI: 10.1073/pnas.2307898120] [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: 05/10/2023] [Accepted: 06/23/2023] [Indexed: 07/26/2023] Open
Abstract
Cells of vertebrate and invertebrate organisms express proteins specialized in membrane channel-based cell-cell communication that are absent in unicellular organisms. We recently described the prediction of some members of the large-pore channel family in kinetoplastids, consisting of proteins called unnexins, which share several structural features with innexin and pannexin proteins. Here, we demonstrated that the unnexin1 protein (Unx1) is delivered to the cell membrane, displaying a topology consisting of four transmembrane domains with C and N termini on the cytoplasmic side and form large-pore channels that are permeable to small molecules. Low extracellular Ca2+/Mg2+ levels or extracellular alkalinization, but not mechanical stretching, increases channel activity. The Unx1 channel mediates the influx of Ca2+ and does not form intercellular dye coupling between HeLa Unx1 transfected cells. Unx1 channel function was further evidenced by its ability to mediate ionic currents when expressed in Xenopus oocytes. Downregulation of Unx1 mRNA with morpholine contains Trypanosoma cruzi invasion. Phylogenetic analysis revealed the presence of Unx1 homologs in other protozoan parasites, suggesting a conserved function for these channel parasites in other protists. Our data demonstrate that Unx1 forms large-pore membrane channels, which may serve as a diffusional pathway for ions and small molecules that are likely to be metabolic substrates or waste products, and signaling autocrine and paracrine molecules that could be involved in cell invasion. As morpholinos-induced downregulation of Unx1 reduces the infectivity of trypomastigotes, the Unx1 channels might be an attractive target for developing trypanocide drugs.
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Affiliation(s)
- Juan Güiza
- Laboratory of Gap Junction Proteins and Parasitic Diseases (GaPaL), Instituto Antofagasta, Universidad de Antofagasta, Antofagasta1240000, Chile
| | - Francisco Solís
- Laboratorio de Microorganismos Extremófilos, Instituto Antofagasta, Universidad de Antofagasta, Antofagasta1240000, Chile
| | - Bernardita Valenzuela
- Laboratorio de Microorganismos Extremófilos, Instituto Antofagasta, Universidad de Antofagasta, Antofagasta1240000, Chile
| | - Duxan Arancibia
- Laboratorio de Microorganismos Extremófilos, Instituto Antofagasta, Universidad de Antofagasta, Antofagasta1240000, Chile
| | - Pedro Zamorano
- Laboratorio de Microorganismos Extremófilos, Instituto Antofagasta, Universidad de Antofagasta, Antofagasta1240000, Chile
| | - Jorge González
- Departamento de Tecnología Médica, Unidad de Parasitología Molecular, Facultad Ciencias de la Salud, Universidad de Antofagasta, Antofagasta1240000, Chile
| | - Jonathan Saavedra
- Instituto de Neurociencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso2381850, Chile
| | - Alan Neely
- Instituto de Neurociencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso2381850, Chile
| | - Magdiel Salgado
- Instituto de Neurociencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso2381850, Chile
| | - Agustín D. Martínez
- Instituto de Neurociencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso2381850, Chile
| | - Juan C. Sáez
- Instituto de Neurociencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso2381850, Chile
| | - José L. Vega
- Laboratory of Gap Junction Proteins and Parasitic Diseases (GaPaL), Instituto Antofagasta, Universidad de Antofagasta, Antofagasta1240000, Chile
- Departamento Biomédico, Facultad de Ciencias de la Salud, Universidad de Antofagasta, Antofagasta1240000, Chile
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Vega JL, Gutiérrez C, Rojas M, Güiza J, Sáez JC. Contribution of large-pore channels to inflammation induced by microorganisms. Front Cell Dev Biol 2023; 10:1094362. [PMID: 36699007 PMCID: PMC9868820 DOI: 10.3389/fcell.2022.1094362] [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: 11/10/2022] [Accepted: 12/22/2022] [Indexed: 01/12/2023] Open
Abstract
Plasma membrane ionic channels selectively permeate potassium, sodium, calcium, and chloride ions. However, large-pore channels are permeable to ions and small molecules such as ATP and glutamate, among others. Large-pore channels are structures formed by several protein families with little or no evolutionary linkages including connexins (Cxs), pannexins (Panxs), innexin (Inxs), unnexins (Unxs), calcium homeostasis modulator (CALHMs), and Leucine-rich repeat-containing 8 (LRRC8) proteins. Large-pore channels are key players in inflammatory cell response, guiding the activation of inflammasomes, the release of pro-inflammatory cytokines such as interleukin-1 beta (IL-1ß), and the release of adenosine-5'-triphosphate (ATP), which is considered a danger signal. This review summarizes our current understanding of large-pore channels and their contribution to inflammation induced by microorganisms, virulence factors or their toxins.
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Affiliation(s)
- José L. Vega
- Laboratory of Gap Junctions Proteins and Parasitic Diseases (GaPaL), Instituto Antofagasta, Universidad de Antofagasta, Antofagasta, Chile,Centro de Investigación en Inmunología y Biotecnología Biomédica de Antofagasta (CIIBBA), Universidad de Antofagasta, Antofagasta, Chile,Centro de Fisiología y Medicina de Altura (FIMEDALT), Universidad de Antofagasta, Antofagasta, Chile,*Correspondence: José L. Vega,
| | - Camila Gutiérrez
- Laboratory of Gap Junctions Proteins and Parasitic Diseases (GaPaL), Instituto Antofagasta, Universidad de Antofagasta, Antofagasta, Chile
| | - Mauro Rojas
- Laboratory of Gap Junctions Proteins and Parasitic Diseases (GaPaL), Instituto Antofagasta, Universidad de Antofagasta, Antofagasta, Chile
| | - Juan Güiza
- Laboratory of Gap Junctions Proteins and Parasitic Diseases (GaPaL), Instituto Antofagasta, Universidad de Antofagasta, Antofagasta, Chile
| | - Juan C. Sáez
- Centro Interdisciplinario de Neurociencias de Valparaíso (CINV), Instituto de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile
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Chagas Heart Disease: Beyond a Single Complication, from Asymptomatic Disease to Heart Failure. J Clin Med 2022; 11:jcm11247262. [PMID: 36555880 PMCID: PMC9784121 DOI: 10.3390/jcm11247262] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 11/18/2022] [Accepted: 11/21/2022] [Indexed: 12/12/2022] Open
Abstract
Chagas cardiomyopathy (CC), caused by the protozoan Trypanosoma cruzi, is an important cause of cardiovascular morbidity and mortality in developing countries. It is estimated that 6 to 7 million people worldwide are infected, and it is predicted that it will be responsible for 200,000 deaths by 2025. The World Health Organization (WHO) considers Chagas disease (CD) as a Neglected Tropical Disease (NTD), which must be acknowledged and detected in time, as it remains a clinical and diagnostic challenge in both endemic and non-endemic regions and at different levels of care. The literature on CC was analyzed by searching different databases (Medline, Cochrane Central, EMBASE, PubMed, Google Scholar, EBSCO) from 1968 until October 2022. Multicenter and bioinformatics trials, systematic and bibliographic reviews, international guidelines, and clinical cases were included. The reference lists of the included papers were checked. No linguistic restrictions or study designs were applied. This review is intended to address the current incidence and prevalence of CD and to identify the main pathogenic mechanisms, clinical presentation, and diagnosis of CC.
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Lecoutre S, Lambert M, Drygalski K, Dugail I, Maqdasy S, Hautefeuille M, Clément K. Importance of the Microenvironment and Mechanosensing in Adipose Tissue Biology. Cells 2022; 11:cells11152310. [PMID: 35954152 PMCID: PMC9367348 DOI: 10.3390/cells11152310] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 07/19/2022] [Accepted: 07/23/2022] [Indexed: 11/16/2022] Open
Abstract
The expansion of adipose tissue is an adaptive mechanism that increases nutrient buffering capacity in response to an overall positive energy balance. Over the course of expansion, the adipose microenvironment undergoes continual remodeling to maintain its structural and functional integrity. However, in the long run, adipose tissue remodeling, typically characterized by adipocyte hypertrophy, immune cells infiltration, fibrosis and changes in vascular architecture, generates mechanical stress on adipose cells. This mechanical stimulus is then transduced into a biochemical signal that alters adipose function through mechanotransduction. In this review, we describe the physical changes occurring during adipose tissue remodeling, and how they regulate adipose cell physiology and promote obesity-associated dysfunction in adipose tissue.
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Affiliation(s)
- Simon Lecoutre
- Nutrition and Obesities: Systemic Approaches Research Group (Nutri-Omics), Sorbonne Université, INSERM, F-75013 Paris, France; (S.L.); (K.D.); (I.D.)
| | - Mélanie Lambert
- Labex Inflamex, Université Sorbonne Paris Nord, INSERM, F-93000 Bobigny, France;
| | - Krzysztof Drygalski
- Nutrition and Obesities: Systemic Approaches Research Group (Nutri-Omics), Sorbonne Université, INSERM, F-75013 Paris, France; (S.L.); (K.D.); (I.D.)
| | - Isabelle Dugail
- Nutrition and Obesities: Systemic Approaches Research Group (Nutri-Omics), Sorbonne Université, INSERM, F-75013 Paris, France; (S.L.); (K.D.); (I.D.)
| | - Salwan Maqdasy
- Department of Medicine (H7), Karolinska Institutet Hospital, C2-94, 14186 Stockholm, Sweden;
| | - Mathieu Hautefeuille
- Laboratoire de Biologie du Développement (UMR 7622), IBPS, Sorbonne Université, F-75005 Paris, France;
| | - Karine Clément
- Nutrition and Obesities: Systemic Approaches Research Group (Nutri-Omics), Sorbonne Université, INSERM, F-75013 Paris, France; (S.L.); (K.D.); (I.D.)
- Assistance Publique Hôpitaux de Paris, Nutrition Department, CRNH Ile-de-France, Pitié-Salpêtrière Hospital, F-75013 Paris, France
- Correspondence: or
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Burl RB, Rondini EA, Wei H, Pique-Regi R, Granneman JG. Deconstructing cold-induced brown adipocyte neogenesis in mice. eLife 2022; 11:e80167. [PMID: 35848799 PMCID: PMC9348851 DOI: 10.7554/elife.80167] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 07/15/2022] [Indexed: 11/21/2022] Open
Abstract
Cold exposure triggers neogenesis in classic interscapular brown adipose tissue (iBAT) that involves activation of β1-adrenergic receptors, proliferation of PDGFRA+ adipose tissue stromal cells (ASCs), and recruitment of immune cells whose phenotypes are presently unknown. Single-cell RNA-sequencing (scRNA-seq) in mice identified three ASC subpopulations that occupied distinct tissue locations. Of these, interstitial ASC1 were found to be direct precursors of new brown adipocytes (BAs). Surprisingly, knockout of β1-adrenergic receptors in ASCs did not prevent cold-induced neogenesis, whereas pharmacological activation of the β3-adrenergic receptor on BAs was sufficient, suggesting that signals derived from mature BAs indirectly trigger ASC proliferation and differentiation. In this regard, cold exposure induced the delayed appearance of multiple macrophage and dendritic cell populations whose recruitment strongly correlated with the onset and magnitude of neogenesis across diverse experimental conditions. High-resolution immunofluorescence and single-molecule fluorescence in situ hybridization demonstrated that cold-induced neogenesis involves dynamic interactions between ASC1 and recruited immune cells that occur on the micrometer scale in distinct tissue regions. Our results indicate that neogenesis is not a reflexive response of progenitors to β-adrenergic signaling, but rather is a complex adaptive response to elevated metabolic demand within brown adipocytes.
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Affiliation(s)
- Rayanne B Burl
- Center for Molecular Medicine and Genetics, Wayne State UniversityDetroitUnited States
| | - Elizabeth Ann Rondini
- Center for Molecular Medicine and Genetics, Wayne State UniversityDetroitUnited States
- Center for Integrative Metabolic and Endocrine Research, Wayne State UniversityDetroitUnited States
| | - Hongguang Wei
- Center for Molecular Medicine and Genetics, Wayne State UniversityDetroitUnited States
- Center for Integrative Metabolic and Endocrine Research, Wayne State UniversityDetroitUnited States
| | - Roger Pique-Regi
- Center for Molecular Medicine and Genetics, Wayne State UniversityDetroitUnited States
| | - James G Granneman
- Center for Molecular Medicine and Genetics, Wayne State UniversityDetroitUnited States
- Center for Integrative Metabolic and Endocrine Research, Wayne State UniversityDetroitUnited States
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Huang M, Song A, Chen X, Ishtiaq S, Wang C, Hadsell DL, Wang QA, Zhu Y. Maternal Adipocyte Connexin43 Gap Junctions Affect Breastmilk Lactose Levels and Neonate Growth in Mice. BIOLOGY 2022; 11:biology11071023. [PMID: 36101404 PMCID: PMC9311998 DOI: 10.3390/biology11071023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 06/28/2022] [Accepted: 07/04/2022] [Indexed: 11/24/2022]
Abstract
Simple Summary Breastfeeding offers many health benefits for both mothers and infants. However, overnutrition and a steady increase in obesity in the U.S. has made it harder for many mothers to produce and express breastmilk. Moreover, the quality of breastmilk from obese mothers is frequently compromised in that it contains fewer nutrients and more inflammatory components. In this study, we used mice to model this phenomenon. We found that short-term high-fat feeding at the start of breeding reduces litter size and pups’ body weight. It also impairs adipocyte remodeling during lactation. Connexin43 is the primary building block for gap junctions in the adipose tissue. It is postulated to play an essential role in adipose tissue remodeling to accommodate mammary gland development and breastmilk production. Using genetically engineered mice without Connexin43 in their adipocytes, we demonstrated that the deletion of adipocyte Connexin43 affects the disappearance of adipocytes during lactation and affects milk composition, which is postulated to impair the pups’ growth. Altogether, this study suggests that increasing or enhancing adipocyte Connexin43 gap junctions may help obese mothers produce better breastmilk to support their neonates. Abstract Breastfeeding offers a broad spectrum of health benefits for infants. However, overnutrition and a steady increase in maternal obesity in the U.S. have made it harder for many mothers to produce and express breastmilk, and the quality of milk from obese mothers is also frequently compromised. Adipocytes, the primary cell type in the non-lactating breast, display a drastic morphological and functional change during lactation in mice. Lipid-filled adipocytes undergo lipolysis, and lipid droplets disappear to provide fatty acids and energy for breastmilk production. Once the animal stops lactation, these lipid-depleted adipocytes return as lipid-laden cells. This dynamic remodeling of the tissue is likely the result of active intercellular communications. Connexin43 (Cx43) is the most abundant connexin in the mammary adipose tissue that makes up the gap junctions for direct intercellular communications. Its expression is increased during lactation and reduced in obese mammary adipose tissue, which is resistant to lactation-induced remodeling. However, whether Cx43 is required for adipocyte remodeling and breastmilk production to support neonates’ growth has not been established. In this study, we used doxycycline-inducible adipocyte-specific Cx43-deleted mice and demonstrated that adipocyte Cx43 played a vital role in determining the carbohydrate levels in breastmilk, which may subsequently affect neonates’ growth.
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Affiliation(s)
- Mingyang Huang
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA; (M.H.); (X.C.); (S.I.); (C.W.); (D.L.H.)
| | - Anying Song
- Department of Molecular Endocrinology, Diabetes and Metabolism Institute, City of Hope Medical Center, Duarte, CA 91010, USA;
| | - Xi Chen
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA; (M.H.); (X.C.); (S.I.); (C.W.); (D.L.H.)
| | - Sarah Ishtiaq
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA; (M.H.); (X.C.); (S.I.); (C.W.); (D.L.H.)
| | - Chunmei Wang
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA; (M.H.); (X.C.); (S.I.); (C.W.); (D.L.H.)
| | - Darryl L. Hadsell
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA; (M.H.); (X.C.); (S.I.); (C.W.); (D.L.H.)
| | - Qiong A. Wang
- Department of Molecular Endocrinology, Diabetes and Metabolism Institute, City of Hope Medical Center, Duarte, CA 91010, USA;
- Correspondence: (Q.A.W.); (Y.Z.); Tel.: +1-626-256-4673 (Q.A.W.); +1-713-798-0378 (Y.Z.)
| | - Yi Zhu
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA; (M.H.); (X.C.); (S.I.); (C.W.); (D.L.H.)
- Correspondence: (Q.A.W.); (Y.Z.); Tel.: +1-626-256-4673 (Q.A.W.); +1-713-798-0378 (Y.Z.)
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Zhu Y, Li N, Huang M, Chen X, An YA, Li J, Zhao S, Funcke JB, Cao J, He Z, Zhu Q, Zhang Z, Wang ZV, Xu L, Williams KW, Li C, Grove K, Scherer PE. Activating Connexin43 gap junctions primes adipose tissue for therapeutic intervention. Acta Pharm Sin B 2022; 12:3063-3072. [PMID: 35865093 PMCID: PMC9293664 DOI: 10.1016/j.apsb.2022.02.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 01/16/2022] [Accepted: 02/08/2022] [Indexed: 12/19/2022] Open
Abstract
Adipose tissue is a promising target for treating obesity and metabolic diseases. However, pharmacological agents usually fail to effectively engage adipocytes due to their extraordinarily large size and insufficient vascularization, especially in obese subjects. We have previously shown that during cold exposure, connexin43 (Cx43) gap junctions are induced and activated to connect neighboring adipocytes to share limited sympathetic neuronal input amongst multiple cells. We reason the same mechanism may be leveraged to improve the efficacy of various pharmacological agents that target adipose tissue. Using an adipose tissue-specific Cx43 overexpression mouse model, we demonstrate effectiveness in connecting adipocytes to augment metabolic efficacy of the β 3-adrenergic receptor agonist Mirabegron and FGF21. Additionally, combing those molecules with the Cx43 gap junction channel activator danegaptide shows a similar enhanced efficacy. In light of these findings, we propose a model in which connecting adipocytes via Cx43 gap junction channels primes adipose tissue to pharmacological agents designed to engage it. Thus, Cx43 gap junction activators hold great potential for combination with additional agents targeting adipose tissue.
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Affiliation(s)
- Yi Zhu
- Touchstone Diabetes Center, Department of Internal Medicine, the University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Na Li
- Touchstone Diabetes Center, Department of Internal Medicine, the University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA
| | - Mingyang Huang
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Xi Chen
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Yu A. An
- Touchstone Diabetes Center, Department of Internal Medicine, the University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA
| | - Jianping Li
- Division of Cardiology, Department of Internal Medicine, the University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA
| | - Shangang Zhao
- Touchstone Diabetes Center, Department of Internal Medicine, the University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA
| | - Jan-Bernd Funcke
- Touchstone Diabetes Center, Department of Internal Medicine, the University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA
| | - Jianhong Cao
- Division of Hypothalamic Research, Department of Internal Medicine, the University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA
| | - Zhenyan He
- Division of Hypothalamic Research, Department of Internal Medicine, the University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA
| | - Qingzhang Zhu
- Touchstone Diabetes Center, Department of Internal Medicine, the University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA
| | - Zhuzhen Zhang
- Touchstone Diabetes Center, Department of Internal Medicine, the University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA
| | - Zhao V. Wang
- Division of Cardiology, Department of Internal Medicine, the University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA
| | - Lin Xu
- Quantitative Biomedical Research Center, Department of Population and Data Sciences, the University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA
- Department of Pediatrics, the University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA
| | - Kevin W. Williams
- Division of Hypothalamic Research, Department of Internal Medicine, the University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA
| | - Chien Li
- Novo Nordisk Research Center, Seattle, WA 98109, USA
| | - Kevin Grove
- Novo Nordisk Research Center, Seattle, WA 98109, USA
| | - Philipp E. Scherer
- Touchstone Diabetes Center, Department of Internal Medicine, the University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA
- Department of Cell Biology, the University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA
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12
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González-Casanova JE, Durán-Agüero S, Caro-Fuentes NJ, Gamboa-Arancibia ME, Bruna T, Bermúdez V, Rojas-Gómez DM. New Insights on the Role of Connexins and Gap Junctions Channels in Adipose Tissue and Obesity. Int J Mol Sci 2021; 22:ijms222212145. [PMID: 34830025 PMCID: PMC8619175 DOI: 10.3390/ijms222212145] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 11/05/2021] [Accepted: 11/05/2021] [Indexed: 12/20/2022] Open
Abstract
Due to the inability to curb the excessive increase in the prevalence of obesity and overweight, it is necessary to comprehend in more detail the factors involved in the pathophysiology and to appreciate more clearly the biochemical and molecular mechanisms of obesity. Thus, understanding the biological regulation of adipose tissue is of fundamental relevance. Connexin, a protein that forms intercellular membrane channels of gap junctions and unopposed hemichannels, plays a key role in adipogenesis and in the maintenance of adipose tissue homeostasis. The expression and function of Connexin 43 (Cx43) during the different stages of the adipogenesis are differentially regulated. Moreover, it has been shown that cell–cell communication decreases dramatically upon differentiation into adipocytes. Furthermore, inhibition of Cx43 degradation or constitutive overexpression of Cx43 blocks adipocyte differentiation. In the first events of adipogenesis, the connexin is highly phosphorylated, which is likely associated with enhanced Gap Junction (GJ) communication. In an intermediate state of adipocyte differentiation, Cx43 phosphorylation decreases, as it is displaced from the membrane and degraded through the proteasome; thus, Cx43 total protein is reduced. Cx is involved in cardiac disease as well as in obesity-related cardiovascular diseases. Different studies suggest that obesity together with a high-fat diet are related to the production of remodeling factors associated with expression and distribution of Cx43 in the atrium.
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Affiliation(s)
- Jorge Enrique González-Casanova
- Facultad de Ciencias de la Salud, Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Santiago 8910060, Chile; (J.E.G.-C.); (N.J.C.-F.)
| | - Samuel Durán-Agüero
- Facultad de Ciencias Para el Cuidado de la Salud, Universidad San Sebastián, Sede Los Leones, Lota 2465, Providencia, Santiago 7500000, Chile;
| | - Nelson Javier Caro-Fuentes
- Facultad de Ciencias de la Salud, Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Santiago 8910060, Chile; (J.E.G.-C.); (N.J.C.-F.)
| | - Maria Elena Gamboa-Arancibia
- Facultad de Química y Biología, Universidad de Santiago de Chile, Av. Libertador Bernardo O’higgins 3363, Estación Central, Santiago 9170022, Chile;
| | - Tamara Bruna
- Centro de Investigación Austral Biotech, Facultad de Ciencias, Universidad Santo Tomás, Avenida Ejercito 146, Santiago 8320000, Chile;
| | - Valmore Bermúdez
- Facultad de Ciencias de la Salud, Universidad Simón Bolívar, Barranquilla 080002, Colombia;
| | - Diana Marcela Rojas-Gómez
- Escuela de Nutrición y Dietética, Facultad de Medicina, Universidad Andres Bello, Santiago 8370321, Chile
- Correspondence: ; Tel.: +56-226618559
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13
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Modulation of Cardiac Arrhythmogenesis by Epicardial Adipose Tissue: JACC State-of-the-Art Review. J Am Coll Cardiol 2021; 78:1730-1745. [PMID: 34674819 DOI: 10.1016/j.jacc.2021.08.037] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 08/06/2021] [Accepted: 08/25/2021] [Indexed: 01/04/2023]
Abstract
Obesity is a significant risk factor for arrhythmic cardiovascular death. Interactions between epicardial adipose tissue (EAT) and myocytes are thought to play a key role in the development of arrhythmias. In this review, the authors investigate the influence of EAT on arrhythmogenesis. First, they summarize electrocardiographic evidence showing the association between increased EAT volume and atrial and ventricular conduction delay. Second, they detail the structural cross talk between EAT and the heart and its arrhythmogenicity. Adipose tissue infiltration within the myocardium constitutes an anatomical obstacle to cardiac excitation. It causes activation delay and increases the risk of arrhythmias. Intercellular electrical coupling between cardiomyocytes and EAT can further slow conduction and increase the risk of block, favoring re-entry and arrhythmias. Finally, EAT secretes multiple substances that influence cardiomyocyte electrophysiology either by modulating ion currents and electrical coupling or by stimulating fibrosis. Thus, structural and paracrine cross talk between EAT and cardiomyocytes facilitates arrhythmias.
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14
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Krishnan A, Chilton E, Raman J, Saxena P, McFarlane C, Trollope AF, Kinobe R, Chilton L. Are Interactions between Epicardial Adipose Tissue, Cardiac Fibroblasts and Cardiac Myocytes Instrumental in Atrial Fibrosis and Atrial Fibrillation? Cells 2021; 10:2501. [PMID: 34572150 PMCID: PMC8467050 DOI: 10.3390/cells10092501] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 09/12/2021] [Accepted: 09/14/2021] [Indexed: 12/12/2022] Open
Abstract
Atrial fibrillation is very common among the elderly and/or obese. While myocardial fibrosis is associated with atrial fibrillation, the exact mechanisms within atrial myocytes and surrounding non-myocytes are not fully understood. This review considers the potential roles of myocardial fibroblasts and myofibroblasts in fibrosis and modulating myocyte electrophysiology through electrotonic interactions. Coupling with (myo)fibroblasts in vitro and in silico prolonged myocyte action potential duration and caused resting depolarization; an optogenetic study has verified in vivo that fibroblasts depolarized when coupled myocytes produced action potentials. This review also introduces another non-myocyte which may modulate both myocardial (myo)fibroblasts and myocytes: epicardial adipose tissue. Epicardial adipocytes are in intimate contact with myocytes and (myo)fibroblasts and may infiltrate the myocardium. Adipocytes secrete numerous adipokines which modulate (myo)fibroblast and myocyte physiology. These adipokines are protective in healthy hearts, preventing inflammation and fibrosis. However, adipokines secreted from adipocytes may switch to pro-inflammatory and pro-fibrotic, associated with reactive oxygen species generation. Pro-fibrotic adipokines stimulate myofibroblast differentiation, causing pronounced fibrosis in the epicardial adipose tissue and the myocardium. Adipose tissue also influences myocyte electrophysiology, via the adipokines and/or through electrotonic interactions. Deeper understanding of the interactions between myocytes and non-myocytes is important to understand and manage atrial fibrillation.
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Affiliation(s)
- Anirudh Krishnan
- College of Medicine and Dentistry, James Cook University, Townsville, QLD 4811, Australia;
| | - Emily Chilton
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC V5A 1S6, Canada;
| | - Jaishankar Raman
- Austin & St Vincent’s Hospitals, Melbourne University, Melbourne, VIC 3010, Australia;
- Applied Artificial Intelligence Institute, Deakin University, Melbourne, VIC 3217, Australia
- Department of Surgery, Oregon Health and Science University, Portland, OR 97239, USA
- School of Engineering, University of Illinois at Urbana-Champaign, Champaign, IL 61820, USA
| | - Pankaj Saxena
- Department of Cardiothoracic Surgery, Townsville University Hospital, Townsville, QLD 4814, Australia;
| | - Craig McFarlane
- Centre for Tropical Bioinformatics and Molecular Biology, Australian Institute of Tropical Health and Medicine, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD 4811, Australia;
| | - Alexandra F. Trollope
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, College of Medicine and Dentistry, James Cook University, Townsville, QLD 4811, Australia;
| | - Robert Kinobe
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD 4811, Australia;
| | - Lisa Chilton
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD 4811, Australia;
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15
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Resende BAM, Beleigoli AMR, Ribeiro ALP, Duncan B, Schmidt MI, Mill JG, Goulart AC, Pereira ADC, Barreto SM, Diniz MDFHS. Chagas disease is not associated with diabetes, metabolic syndrome, insulin resistance and beta cell dysfunction at baseline of Brazilian Longitudinal Study of Adult Health (ELSA-Brasil). Parasitol Int 2021; 85:102440. [PMID: 34411740 DOI: 10.1016/j.parint.2021.102440] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 07/12/2021] [Accepted: 08/13/2021] [Indexed: 11/20/2022]
Abstract
Chagas disease (ChD) affects millions of people worldwide, being endemic in Latin America and emerging in the United States and Europe. Classically described as targeting the heart and gastrointestinal tract, Trypanosoma cruzi parasitism leads to structural and pro-inflammatory changes in the adipose tissue and pancreas. The effects of these changes on insulin resistance (IR), beta cell dysfunction, diabetes mellitus (DM),and metabolic syndrome (MS) are unclear. We aim to evaluate the association of ChD with DM, IR, beta cell dysfunction and MS in the baseline of multi-centric cohort study 'Brazilian Longitudinal Study of Adult Health' (ELSA-Brasil). This cross-sectional analysis included 14,922 (98%) participants of ELSA-Brasil at baseline. To investigate the associations of ChD with DM, IR (assessed by HOMA-IR) and beta cell dysfunction (assessed by HOMA beta), and MS we fitted logistic regression models including socio-demographic and anthropometric variables, health-related conditions and laboratory results. ChD, defined by positive serology, was prevalent in 1.9% (n = 283) of the sample, 17.3% (n = 49) of whom had cardiomyopathy. DM prevalence was 17.25% (n = 2574) and was not different among those with and without ChD (20.5% vs 17.2%; p = 0.28). Fasting and 2 h-blood glucose after a 75 g anhydrous glucose were slightly higher among participants positive for ChD, when compared with those with negative serology (102 mg/dL versus 100 mg/dL, respectively; and 127 mg/dL versus 124 mg/dL, respectively), only in univariate analysis. There was no significant association between these variables and ChD after adjustments. In addition, there was no significant association between DM, IR, beta cell dysfunction or MS and ChD (without and with cardiomyopathy). Our results showed that ChD, regardless of the presence of cardiomyopathy, is not associated with DM, IR, beta cell dysfunction or MS. These findings suggest the parasitism of the adipose tissue and pancreas in Chagas disease do not translate into clinically relevant glucose abnormalities.
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Affiliation(s)
- Bruna A M Resende
- Internal Medicine Department, Faculty of Medicine, Faculdade Atenas, Sete Lagoas, Minas Gerais, Brazil
| | - Alline M R Beleigoli
- College of Nursing and Health Sciences, Flinders University, Adelaide, South Australia, Australia
| | - Antonio Luiz Pinho Ribeiro
- Internal Medicine Department, Faculty of Medicine, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Bruce Duncan
- Postgraduate Program in Epidemiology and Hospital de Clínicas de Porto Alegre, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Maria Inês Schmidt
- Postgraduate Program in Epidemiology and Hospital de Clínicas de Porto Alegre, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - José Geraldo Mill
- Department of Physiological Sciences, Federal University of Espirito Santo, Vitória, Espírito Santo, Brazil
| | | | - Alexandre da Costa Pereira
- Laboratorio de Genetica e Cardiologia Molecular, Instituto do Coração, Faculdade de Medicina da Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - Sandhi Maria Barreto
- Public Health Department, Faculty of Medicine, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
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16
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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: 13] [Impact Index Per Article: 4.3] [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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17
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Mannino G, Vicario N, Parenti R, Giuffrida R, Lo Furno D. Connexin expression decreases during adipogenic differentiation of human adipose-derived mesenchymal stem cells. Mol Biol Rep 2020; 47:9951-9958. [PMID: 33141287 DOI: 10.1007/s11033-020-05950-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 10/23/2020] [Indexed: 02/08/2023]
Abstract
Adipose-derived stem cells (ASCs) represent a valuable tool for regenerative medicine being able to differentiate toward several cell lines, such as adipocytes, chondrocytes and osteocytes. During ASC adipogenic differentiation, changes in connexin (Cx) expression were evaluated in the present study. Three different Cxs were investigated: Cx43, Cx32 and Cx31.9. Cx43 is the most abundant in human tissues, Cx32 is prevalently found in nervous tissue and Cx31.9 is found at the myocardial level. Human ASCs undergoing adipogenic differentiation were isolated from raw lipoaspirate and characterized as mesenchymal stem cells. After multiple days of culture (1, 7, 14, 21 and 28 days), adipogenic differentiation was assessed by Oil Red O staining and Acetyl-CoA carboxylase (ACC) levels by western blotting. Cx expression was evaluated by western blotting at the same time points. In treated ASCs, lipidic vacuoles were detected from day 7 of treatment. Their number and size progressively increased over the entire period of observation. A parallel increase of ACC expression was also found. Lower levels of Cx expression were detected during adipogenic differentiation. Such decreases were particularly evident for Cx32, already after the first day of treatment. Cx31.9 and Cx43 also decreased, but starting from day 7. Our results suggest that ASCs may initially be equipped with a variety of Cxs, which is not surprising assuming their multipotential differentiation ability. Although some Cxs may be selectively enhanced depending on specific induction strategies toward different tissues, they seem markedly downregulated during adipogenic differentiation.
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Affiliation(s)
- Giuliana Mannino
- Department of Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, via Santa Sofia 97, 95123, Catania, Italy
| | - Nunzio Vicario
- Department of Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, via Santa Sofia 97, 95123, Catania, Italy
| | - Rosalba Parenti
- Department of Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, via Santa Sofia 97, 95123, Catania, Italy
| | - Rosario Giuffrida
- Department of Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, via Santa Sofia 97, 95123, Catania, Italy.
| | - Debora Lo Furno
- Department of Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, via Santa Sofia 97, 95123, Catania, Italy
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18
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Pope BD, Warren CR, Dahl MO, Pizza CV, Henze DE, Sinatra NR, Gonzalez GM, Chang H, Liu Q, Glieberman AL, Ferrier JP, Cowan CA, Parker KK. Fattening chips: hypertrophy, feeding, and fasting of human white adipocytes in vitro. LAB ON A CHIP 2020; 20:4152-4165. [PMID: 33034335 PMCID: PMC7818847 DOI: 10.1039/d0lc00508h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Adipose is a distributed organ that performs vital endocrine and energy homeostatic functions. Hypertrophy of white adipocytes is a primary mode of both adaptive and maladaptive weight gain in animals and predicts metabolic syndrome independent of obesity. Due to the failure of conventional culture to recapitulate adipocyte hypertrophy, technology for production of adult-size adipocytes would enable applications such as in vitro testing of weight loss therapeutics. To model adaptive adipocyte hypertrophy in vitro, we designed and built fat-on-a-chip using fiber networks inspired by extracellular matrix in adipose tissue. Fiber networks extended the lifespan of differentiated adipocytes, enabling growth to adult sizes. By micropatterning preadipocytes in a native cytoarchitecture and by adjusting cell-to-cell spacing, rates of hypertrophy were controlled independent of culture time or differentiation efficiency. In vitro hypertrophy followed a nonlinear, nonexponential growth model similar to human development and elicited transcriptomic changes that increased overall similarity with primary tissue. Cells on the chip responded to simulated meals and starvation, which potentiated some adipocyte endocrine and metabolic functions. To test the utility of the platform for therapeutic development, transcriptional network analysis was performed, and retinoic acid receptors were identified as candidate drug targets. Regulation by retinoid signaling was suggested further by pharmacological modulation, where activation accelerated and inhibition slowed hypertrophy. Altogether, this work presents technology for mature adipocyte engineering, addresses the regulation of cell growth, and informs broader applications for synthetic adipose in pharmaceutical development, regenerative medicine, and cellular agriculture.
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Affiliation(s)
- Benjamin D Pope
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Pierce Hall, Room 318, 29 Oxford Street, Cambridge, MA 02138, USA. and Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Curtis R Warren
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Madeleine O Dahl
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Pierce Hall, Room 318, 29 Oxford Street, Cambridge, MA 02138, USA.
| | - Christina V Pizza
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Pierce Hall, Room 318, 29 Oxford Street, Cambridge, MA 02138, USA.
| | - Douglas E Henze
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Pierce Hall, Room 318, 29 Oxford Street, Cambridge, MA 02138, USA.
| | - Nina R Sinatra
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Pierce Hall, Room 318, 29 Oxford Street, Cambridge, MA 02138, USA.
| | - Grant M Gonzalez
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Pierce Hall, Room 318, 29 Oxford Street, Cambridge, MA 02138, USA.
| | - Huibin Chang
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Pierce Hall, Room 318, 29 Oxford Street, Cambridge, MA 02138, USA.
| | - Qihan Liu
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Pierce Hall, Room 318, 29 Oxford Street, Cambridge, MA 02138, USA.
| | - Aaron L Glieberman
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Pierce Hall, Room 318, 29 Oxford Street, Cambridge, MA 02138, USA.
| | - John P Ferrier
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Pierce Hall, Room 318, 29 Oxford Street, Cambridge, MA 02138, USA.
| | - Chad A Cowan
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA and Harvard Stem Cell Institute, Cambridge, MA 02138, USA
| | - Kevin Kit Parker
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Pierce Hall, Room 318, 29 Oxford Street, Cambridge, MA 02138, USA. and Harvard Stem Cell Institute, Cambridge, MA 02138, USA
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19
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Hu J, Li X, Judd RL, Easley CJ. Rapid lipolytic oscillations in ex vivo adipose tissue explants revealed through microfluidic droplet sampling at high temporal resolution. LAB ON A CHIP 2020; 20:1503-1512. [PMID: 32239045 PMCID: PMC7380261 DOI: 10.1039/d0lc00103a] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Our understanding of adipose tissue biology has steadily evolved. While structural and energy storage functionalities have been in the forefront, a key endocrine role for adipocytes was revealed only over the last few decades. In contrast to the wealth of information on dynamic function of other endocrine tissues, few studies have focused on dynamic adipose tissue function or on tool development toward that end. Here, we apply our unique droplet-based microfluidic devices to culture, perfuse, and sample secretions from primary murine epididymal white adipose tissue (eWAT), and from predifferentiated clusters of 3T3-L1 adipocytes. Through automated control, oil-segmented aqueous droplets (∼2.6 nL) were sampled from tissue or cells at 3.5 second temporal resolution (including sample and reference droplets), with integrated enzyme assays enabling real-time quantification of glycerol (down to 1.9 fmol per droplet). This high resolution revealed previously unreported oscillations in secreted glycerol at frequencies of 0.2 to 2.0 min-1 (∼30-300 s periods) present in the primary tissue but not in clustered cells. Low-level bursts (∼50 fmol) released in basal conditions were contrasted with larger bursts (∼300 fmol) during stimulation. Further, both fold changes and burst magnitudes were decreased in eWAT of aged and obese mice. These results, combined with immunostaining and photobleaching analyses, suggest that gap-junctional coupling or nerve cell innervation within the intact ex vivo tissue explants play important roles in this apparent tissue-level, lipolytic synchronization. High-resolution, quantitative sampling by droplet microfluidics thus permitted unique biological information to be observed, giving an analytical framework poised for future studies of dynamic oscillatory function of adipose and other tissues.
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Affiliation(s)
- Juan Hu
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849, USA.
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20
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Severe Myocardial Steatosis: Incidental Finding or a Significant Anatomic Substrate for Sudden Cardiac Arrest? Am J Forensic Med Pathol 2020; 41:42-47. [PMID: 32000221 DOI: 10.1097/paf.0000000000000531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Myocardial steatosis, also known as lipomatosis cordis, is characterized by adipose tissue within the myocardium without significant fibrosis. Evidence suggests that accumulation of fat can disturb the normal electromechanical physiology of the myocardium. Herein, we discuss the case of a 60-year-old woman with a history of chronic obstructive pulmonary disease who died because of anoxic encephalopathy after a sudden cardiac arrest (SCA). An electrocardiogram showed QRS fragmentation noted as notched R in inferior leads. The autopsy revealed a very small thromboembolus in a distal subsegmental branch of the pulmonary artery, which could not explain the SCA. There was an extensive intramyocardial accumulation of adipose tissue involving the right ventricle and interventricular septum, which split the myocardium into discrete bundles. Arrhythmogenic right ventricular cardiomyopathy was ruled out based on the absence of typical fibrofatty changes. The mechanism of fat replacement was likely secondary to redistribution of visceral fat in the setting of Cushing syndrome. We propose that severe myocardial steatosis can create an anatomic substrate to facilitate the development of SCA. Myocardial steatosis should be reported to identify patients who are at risk for developing cardiovascular events secondary to extreme cardiac adiposity.
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21
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Bielczyk-Maczynska E. White Adipocyte Plasticity in Physiology and Disease. Cells 2019; 8:E1507. [PMID: 31775295 PMCID: PMC6953026 DOI: 10.3390/cells8121507] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Revised: 11/19/2019] [Accepted: 11/21/2019] [Indexed: 12/15/2022] Open
Abstract
Cellular plasticity is a transformation of a terminally differentiated cell into another cell type, which has been long known to occur in disease and regeneration. However, white adipocytes (fat cells) have only recently been observed to undergo different types of cellular plasticity. Adipocyte transdifferentiation into myofibroblasts and cancer-associated fibroblasts occurs in fibrosis and cancer, respectively. On the other hand, reversible adipocyte dedifferentiation into adipocyte progenitor cells (preadipocytes) has been demonstrated in mammary gland and in dermal adipose tissue. Here we discuss the research on adipocyte plasticity, including the experimental approaches that allowed to detect and study it, the current state of the knowledge, major research questions which remain to be addressed, and the advances required to stimulate adipocyte plasticity research. In the future, the knowledge of the molecular mechanisms of adipocyte plasticity can be utilized both to prevent adipocyte plasticity in disease and to stimulate it for use in regenerative medicine.
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Affiliation(s)
- Ewa Bielczyk-Maczynska
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA 94305, USA
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Shao Q, Esseltine JL, Huang T, Novielli-Kuntz N, Ching JE, Sampson J, Laird DW. Connexin43 is Dispensable for Early Stage Human Mesenchymal Stem Cell Adipogenic Differentiation But is Protective against Cell Senescence. Biomolecules 2019; 9:E474. [PMID: 31514306 PMCID: PMC6770901 DOI: 10.3390/biom9090474] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 09/05/2019] [Accepted: 09/07/2019] [Indexed: 02/07/2023] Open
Abstract
In the last couple of decades, there has been a growing optimism surrounding the potential transformative use of human mesenchymal stem cells (MSCs) and human-induced pluripotent stem cells (iPSCs) for regenerative medicine and disease treatment. In order for this to occur, it is first essential to understand the mechanisms underpinning their cell-fate specification, which includes cell signaling via gap junctional intercellular communication. Here, we investigated the role of the prototypical gap junction protein, connexin43 (Cx43), in governing the differentiation of iPSCs into MSCs and MSC differentiation along the adipogenic lineage. We found that control iPSCs, as well as iPSCs derived from oculodentodigital dysplasia patient fibroblasts harboring a GJA1 (Cx43) gene mutation, successfully and efficiently differentiated into LipidTox and perilipin-positive cells, indicating cell differentiation along the adipogenic lineage. Furthermore, the complete CRISPR-Cas9 ablation of Cx43 from iPSCs did not prevent their differentiation into bona fide MSCs or pre-adipocytes, strongly suggesting that even though Cx43 expression is upregulated during adipogenesis, it is expendable. Interestingly, late passage Cx43-ablated MSCs senesced more quickly than control cells, resulting in failure to properly differentiate in vitro. We conclude that despite being upregulated during adipogenesis, Cx43 plays no detectable role in the early stages of human iPSC-derived MSC adipogenic differentiation. However, Cx43 may play a more impactful role in protecting MSCs from premature senescence.
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Affiliation(s)
- Qing Shao
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON N6A 5C1, Canada.
| | - Jessica L Esseltine
- Division of BioMedical Sciences, Memorial University of Newfoundland, St. John's, NL A1B 3V6, Canada.
| | - Tao Huang
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON N6A 5C1, Canada.
- Department of Pathology, Shenyang Medical College, Shenyang 110034, China.
| | - Nicole Novielli-Kuntz
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON N6A 5C1, Canada.
| | - Jamie E Ching
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON N6A 5C1, Canada.
| | - Jacinda Sampson
- Department of Neurology, Stanford University Medical Center, Palo Alto, CA 94304, USA.
| | - Dale W Laird
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON N6A 5C1, Canada.
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON N6A 5C1, Canada.
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23
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Pietak A, Levin M. Bioelectrical control of positional information in development and regeneration: A review of conceptual and computational advances. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2018; 137:52-68. [PMID: 29626560 PMCID: PMC10464501 DOI: 10.1016/j.pbiomolbio.2018.03.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Revised: 03/23/2018] [Accepted: 03/26/2018] [Indexed: 12/16/2022]
Abstract
Positional information describes pre-patterns of morphogenetic substances that alter spatio-temporal gene expression to instruct development of growth and form. A wealth of recent data indicate bioelectrical properties, such as the transmembrane potential (Vmem), are involved as instructive signals in the spatiotemporal regulation of morphogenesis. However, the mechanistic relationships between Vmem and molecular positional information are only beginning to be understood. Recent advances in computational modeling are assisting in the development of comprehensive frameworks for mechanistically understanding how endogenous bioelectricity can guide anatomy in a broad range of systems. Vmem represents an extraordinarily strong electric field (∼1.0 × 106 V/m) active over the thin expanse of the plasma membrane, with the capacity to influence a variety of downstream molecular signaling cascades. Moreover, in multicellular networks, intercellular coupling facilitated by gap junction channels may induce directed, electrodiffusive transport of charged molecules between cells of the network to generate new positional information patterning possibilities and characteristics. Given the demonstrated role of Vmem in morphogenesis, here we review current understanding of how Vmem can integrate with molecular regulatory networks to control single cell state, and the unique properties bioelectricity adds to transport phenomena in gap junction-coupled cell networks to facilitate self-assembly of morphogen gradients and other patterns. Understanding how Vmem integrates with biochemical regulatory networks at the level of a single cell, and mechanisms through which Vmem shapes molecular positional information in multicellular networks, are essential for a deep understanding of body plan control in development, regeneration and disease.
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Affiliation(s)
| | - Michael Levin
- Allen Discovery Center at Tufts, USA; Center for Regenerative and Developmental Biology, Tufts University, Medford, MA, USA
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24
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Lee KH, Kim NH. Expressional Patterns of Connexin Isoforms in the Rat Epididymal Fat during Postnatal Development. Dev Reprod 2018; 22:29-38. [PMID: 29707682 PMCID: PMC5915765 DOI: 10.12717/dr.2018.22.1.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/10/2018] [Accepted: 03/17/2018] [Indexed: 12/31/2022]
Abstract
In the multicellular tissue, cell-cell interaction is important for a precise
control of its function. The exchange of signaling molecules between adjacent
cells via connexon allows the functional harmony of cells in the tissue. The
present research was to determine the presence and expressional patterns of
connexin (Cx) isoforms in the rat epididymal fat during
postnatal development using quantitative real-time polymerase chain reaction
(PCR) analysis. Of 13 Cx isoforms examined, expression of 11
Cx isoforms in the epididymal fat during postnatal
development was detected. These Cx isoforms include
Cx26, Cx31, Cx31.1,
Cx32, Cx33, Cx36,
Cx37, Cx40, Cx43,
Cx45, and Cx50. Expressional levels of all
Cx isoforms at 1 and 2 years of age were significantly
higher than those at the early postnatal ages, such as 7 days, 14 days, and 24
days of ages. Except Cx33 and Cx43, the
transcript levels of rest Cx isoforms at 1 year of age were
significantly lower than that at 2 years of age. In addition, expressional
patterns of Cx isoforms between 7 days and 5 months of ages
generally varied according to the isoform. The existence of various
Cx isoforms in the rat epididymal fat has been identified
and expression of each Cx isoform in the epididymal fat during
postnatal development has shown a particular pattern, distinguishable from the
others. To our knowledges, this is the first report showing expressional
patterns of Cx isoforms at transcript level in the epididymal
fat at various postnatal ages.
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Affiliation(s)
- Ki-Ho Lee
- Dept. of Biochemistry and Molecular Biology, College of Medicine, Eulji University, Daejeon 34824, Korea
| | - Nan Hee Kim
- Dept. of Biochemistry and Molecular Biology, College of Medicine, Eulji University, Daejeon 34824, Korea
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25
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Anumonwo JMB, Herron T. Fatty Infiltration of the Myocardium and Arrhythmogenesis: Potential Cellular and Molecular Mechanisms. Front Physiol 2018; 9:2. [PMID: 29403390 PMCID: PMC5786512 DOI: 10.3389/fphys.2018.00002] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 01/03/2018] [Indexed: 11/13/2022] Open
Abstract
Anatomical evidence in several species shows highly heterogeneous fat distribution in the atrial and ventricular myocardium. Atrial appendages have fat deposits, and more so on the posterior left atrium. Although such fat distributions are considered normal, fatty infiltration is regarded arrhythmogenic, and various cardiac pathophysiological conditions show excess myocardial fat deposits, especially in the epicardium. Hypotheses have been presented for the physiological and pathophysiological roles of epicardial fat, however this issue is poorly understood. Therefore, this mini-review will focus on epicardial fat distribution and the (patho)-physiological implications of this distribution. Potential molecular mechanisms that may drive structural and electrical myocardial remodeling attendant to fatty infiltration of the heart are also reviewed.
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Affiliation(s)
- Justus M B Anumonwo
- Department of Internal Medicine (Cardiovascular Medicine), Center for Arrythmia Research, University of Michigan, Ann Arbor, MI, United States
| | - Todd Herron
- Department of Internal Medicine (Cardiovascular Medicine), Center for Arrythmia Research, University of Michigan, Ann Arbor, MI, United States
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26
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Connexin 43 is required for the maintenance of mitochondrial integrity in brown adipose tissue. Sci Rep 2017; 7:7159. [PMID: 28769076 PMCID: PMC5540980 DOI: 10.1038/s41598-017-07658-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 06/30/2017] [Indexed: 11/09/2022] Open
Abstract
We investigated the role of connexin 43 (Cx43) in maintaining the integrity of mitochondria in brown adipose tissue (BAT). The functional effects of Cx43 were evaluated using inducible, adipocyte-specific Cx43 knockout in mice (Gja1adipoqKO) and by overexpression and knockdown of Cx43 in cultured adipocytes. Mitochondrial morphology was evaluated by electron microscopy and mitochondrial function and autophagy were assessed by immunoblotting, immunohistochemistry, and qPCR. The metabolic effects of adipocyte-specific knockout of Cx43 were assessed during cold stress and following high fat diet feeding. Cx43 expression was higher in BAT compared to white adipose tissue. Treatment with the β3-adrenergic receptor agonist CL316,243 increased Cx43 expression and mitochondrial localization. Gja1adipoqKO mice reduced mitochondrial density and increased the presence of damaged mitochondria in BAT. Moreover, metabolic activation with CL316,243 further reduced mitochondrial integrity and upregulated autophagy in the BAT of Gja1adipoqKO mice. Inhibition of Cx43 in cultured adipocytes increased the generation of reactive oxygen species and induction of autophagy during β-adrenergic stimulation. Gja1adipoqKO mice were cold intolerant, expended less energy in response to β3-adrenergic receptor activation, and were more insulin resistant after a high-fat diet challenge. Collectively, our data demonstrate that Cx43 is required for maintaining the mitochondrial integrity and metabolic activity of BAT.
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27
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Becnel LB, Ochsner SA, Darlington YF, McOwiti A, Kankanamge WH, Dehart M, Naumov A, McKenna NJ. Discovering relationships between nuclear receptor signaling pathways, genes, and tissues in Transcriptomine. Sci Signal 2017; 10:10/476/eaah6275. [DOI: 10.1126/scisignal.aah6275] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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28
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Tanowitz HB, Scherer PE, Mota MM, Figueiredo LM. Adipose Tissue: A Safe Haven for Parasites? Trends Parasitol 2016; 33:276-284. [PMID: 28007406 DOI: 10.1016/j.pt.2016.11.008] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 11/17/2016] [Accepted: 11/28/2016] [Indexed: 12/13/2022]
Abstract
Adipose tissue (AT) is no longer regarded as an inert lipid storage, but as an important central regulator in energy homeostasis and immunity. Three parasite species are uniquely associated with AT during part of their life cycle: Trypanosoma cruzi, the causative agent of Chagas disease; Trypanosoma brucei, the causative agent of African sleeping sickness; and Plasmodium spp., the causative agents of malaria. In AT, T. cruzi resides inside adipocytes, T. brucei is found in the interstitial spaces between adipocytes, while Plasmodium spp. infect red blood cells, which may adhere to the blood vessels supplying AT. Here, we discuss how each parasite species adapts to this tissue environment and what the implications are for pathogenesis, clinical manifestations, and therapy.
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Affiliation(s)
- Herbert B Tanowitz
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Philipp E Scherer
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-8549, USA; Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Maria M Mota
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Luisa M Figueiredo
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal.
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29
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Zhu Y, Gao Y, Tao C, Shao M, Zhao S, Huang W, Yao T, Johnson JA, Liu T, Cypess AM, Gupta O, Holland WL, Gupta RK, Spray DC, Tanowitz HB, Cao L, Lynes MD, Tseng YH, Elmquist JK, Williams KW, Lin HV, Scherer PE. Connexin 43 Mediates White Adipose Tissue Beiging by Facilitating the Propagation of Sympathetic Neuronal Signals. Cell Metab 2016; 24:420-433. [PMID: 27626200 PMCID: PMC5024720 DOI: 10.1016/j.cmet.2016.08.005] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 06/28/2016] [Accepted: 08/10/2016] [Indexed: 01/09/2023]
Abstract
"Beige" adipocytes reside in white adipose tissue (WAT) and dissipate energy as heat. Several studies have shown that cold temperature can activate pro-opiomelanocortin-expressing (POMC) neurons and increase sympathetic neuronal tone to regulate WAT beiging. WAT, however, is traditionally known to be sparsely innervated. Details regarding the neuronal innervation and, more importantly, the propagation of the signal within the population of "beige" adipocytes are sparse. Here, we demonstrate that beige adipocytes display an increased cell-to-cell coupling via connexin 43 (Cx43) gap junction channels. Blocking of Cx43 channels by 18α-glycyrrhetinic acid decreases POMC-activation-induced adipose tissue beiging. Adipocyte-specific deletion of Cx43 reduces WAT beiging to a level similar to that observed in denervated fat pads. In contrast, overexpression of Cx43 is sufficient to promote beiging even with mild cold stimuli. These data reveal the importance of cell-to-cell communication, effective in cold-induced WAT beiging, for the propagation of limited neuronal inputs in adipose tissue.
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Affiliation(s)
- Yi Zhu
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Lilly Research Laboratories, Division of Eli Lilly and Company, Indianapolis, IN 46285, USA
| | - Yong Gao
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; National Laboratory of Medical Molecular Biology, Institute of Basic Medical Science, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100005, People's Republic of China
| | - Caroline Tao
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Mengle Shao
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Shangang Zhao
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Wei Huang
- Department of Cancer Biology and Genetics, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Ting Yao
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Medicine, 76 West Yanta Road, Xi'an, Shaanxi 710061, People's Republic of China
| | - Joshua A Johnson
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Tiemin Liu
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Aaron M Cypess
- Translational Physiology Section, Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA
| | - Olga Gupta
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - William L Holland
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Rana K Gupta
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - David C Spray
- Departments of Neuroscience and Medicine (Cardiology), Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Herbert B Tanowitz
- Departments of Pathology and Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Lei Cao
- Department of Cancer Biology and Genetics, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Matthew D Lynes
- Joslin Diabetes Center, Harvard Medical School, Boston, MA 02215, USA
| | - Yu-Hua Tseng
- Joslin Diabetes Center, Harvard Medical School, Boston, MA 02215, USA
| | - Joel K Elmquist
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Kevin W Williams
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Hua V Lin
- Lilly Research Laboratories, Division of Eli Lilly and Company, Indianapolis, IN 46285, USA
| | - Philipp E Scherer
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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30
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Microenvironmental Control of Adipocyte Fate and Function. Trends Cell Biol 2016; 26:745-755. [PMID: 27268909 DOI: 10.1016/j.tcb.2016.05.005] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 05/09/2016] [Accepted: 05/16/2016] [Indexed: 01/07/2023]
Abstract
The properties of tissue-specific microenvironments vary widely in the human body and demonstrably influence the structure and function of many cell types. Adipocytes are no exception, responding to cues in specialized niches to perform vital metabolic and endocrine functions. The adipose microenvironment is remodeled during tissue expansion to maintain the structural and functional integrity of the tissue and disrupted remodeling in obesity contributes to the progression of metabolic syndrome, breast cancer, and other malignancies. The increasing incidence of these obesity-related diseases and the recent focus on improved in vitro models of human tissue biology underscore growing interest in the regulatory role of adipocyte microenvironments in health and disease.
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