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Abebe EC, Mengstie MA, Seid MA, Malik T, Dejenie TA. The evolving roles of alarin in physiological and disease conditions, and its future potential clinical implications. Front Endocrinol (Lausanne) 2022; 13:1028982. [PMID: 36246892 PMCID: PMC9556965 DOI: 10.3389/fendo.2022.1028982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 09/12/2022] [Indexed: 11/30/2022] Open
Abstract
Alarin is a member of the galanin family of neuropeptides that is widely expressed in the central nervous system and peripheral tissues in humans and rodents. It was initially isolated fifteen years ago in ganglionic cells of human neuroblastoma. Subsequently, it was demonstrated to be broadly distributed in the blood vessels, skin, eyes, peripheral and central nervous systems, thymus, gastrointestinal tract, and endocrine organs of different species. Alarin is a 25 amino acid neuropeptide derived from the alternative splicing of the GALP gene, missing exon 3. It is found to be involved in several physiological functions that include feeding behavior, energy homeostasis, glucose homeostasis, body temperature, and reproduction. It has also vasoactive, anti-inflammatory, anti-edema, and antimicrobial activities. However, the physiological effects of alarin have not been fully elucidated and the receptors that mediate these effects are not currently known. Unearthing the novel biological effects of alarin and its unidentified receptors will therefore be a task in future biomedical research. In addition, alarin is involved in various disease conditions, such as metabolic syndrome, obesity, insulin resistance, type 2 diabetes, diabetic retinopathy, hypertension, cardiac fibrosis, polycystic ovarian syndrome, and depression. Thus, alarin may serve as a promising tool for future pharmacological treatment and diagnosis. But further research is awaited to confirm whether alarin has a protective or pathological role in these diseases. This article provides a comprehensive review on the evolving implications of alarin in a variety of physiological and disease conditions, and its future perspectives.
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Affiliation(s)
- Endeshaw Chekol Abebe
- Department of Medical Biochemistry, College of Health Sciences, Debre Tabor University, Debre Tabor, Ethiopia
- *Correspondence: Endeshaw Chekol Abebe,
| | - Misganaw Asmamaw Mengstie
- Department of Medical Biochemistry, College of Health Sciences, Debre Tabor University, Debre Tabor, Ethiopia
| | - Mohammed Abdu Seid
- Department of Physiology, College of Health Sciences, Debre Tabor University, Debre Tabor, Ethiopia
| | - Tabarak Malik
- Department of Medical Biochemistry, College of Medicine and Health Sciences, University of Gondar, Gondar, Ethiopia
| | - Tadesse Asmamaw Dejenie
- Department of Medical Biochemistry, College of Medicine and Health Sciences, University of Gondar, Gondar, Ethiopia
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Li M, Wu M, Zhu H, Hua Y, Ma Z, Yao J, Feng B, Shi B. Serum Tenascin-C and Alarin Levels Are Associated with Cardiovascular Diseases in Type 2 Diabetes Mellitus. Int J Endocrinol 2022; 2022:2009724. [PMID: 35493201 PMCID: PMC9050282 DOI: 10.1155/2022/2009724] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Accepted: 04/11/2022] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Tenascin-C (TNC), an extracellular matrix glycoprotein, is elevated in inflammatory and cardiovascular pathologies, whereas alarin, a novel orexigenic peptide, participates in insulin resistance and glycometabolism. The roles of these molecules in individuals with cardiovascular disease (CVD) and type 2 diabetes mellitus (T2DM), clinical conditions associating with metabolic disorders, and chronic inflammation, remain controversial. Our study aimed at determining the potential role of TNC and alarin in CVD adult patients with T2DM. METHODS This was a cross-sectional study. Basic and clinical information for 250 patients with T2DM were analyzed. Based on their cardiovascular disease status, participants were assigned into the CVD and non-CVD groups. Serum TNC and alarin levels were assessed by enzyme-linked immunosorbent assay (ELISA). RESULTS Serum TNC and alarin concentrations in the CVD group were significantly higher than those of the non-CVD group. Moreover, serum TNC levels were positively correlated with age, waist circumference, and waist-hip ratio; however, they were negatively correlated with TC, LDL-C, and eGFR levels. Alarin levels were positively correlated with BMI, waist circumference, and hip circumference. In logistic regression models, TNC and alarin were also established to be independent determinants for CVD in T2DM patients and their increases were associated with CVD severity. Receiver operating characteristic (ROC) curve analysis showed that the area under curve (AUC) values for TNC and alarin were 0.68 and 0.67, respectively. TNC and alarin were good predictors of CVD occurrence. When the cutoff value for TNC was 134.05 pg/mL, its sensitivity was 69.47% while its specificity was 61.29%. When the cutoff value for alarin was 142.69 pg/mL, sensitivity and specificity were 38.95% and 90.97%, respectively. CONCLUSION Elevated TNC and alarin levels are independently associated with the occurrence and severity of CVD in T2DM individuals. Therefore, these two biomarkers are potential diagnostic and prognostic indicators for CVD in diabetics.
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Affiliation(s)
- Mingming Li
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of Soochow University, Suzhou 215006, China
| | - Mengjiao Wu
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of Soochow University, Suzhou 215006, China
| | - Hua Zhu
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of Soochow University, Suzhou 215006, China
| | - Yulin Hua
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of Soochow University, Suzhou 215006, China
| | - Zijun Ma
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of Soochow University, Suzhou 215006, China
| | - Jiayi Yao
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of Soochow University, Suzhou 215006, China
| | - Bin Feng
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of Soochow University, Suzhou 215006, China
| | - Bimin Shi
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of Soochow University, Suzhou 215006, China
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Oliveira Volpe CM, Vaz T, Rocha-Silva F, Villar-Delfino PH, Nogueira-Machado JA. Is Galanin a Promising Therapeutic Resource for Neural and Nonneural Diseases? Curr Drug Targets 2021; 21:922-929. [PMID: 32096740 DOI: 10.2174/1389450121666200225112055] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 01/21/2020] [Accepted: 01/24/2020] [Indexed: 12/24/2022]
Abstract
BACKGROUND Galanin (GAL) constitutes a family of neuropeptides composed of four peptides: (i) galanin (GAL), (ii) galanin-message associated peptide (GAMP), (iii) galanin-like peptide (GALP), and (iv) alarin. GAL contains 29/30 amino acids, and its biological action occurs through the interactions with its various receptors (GALR1, GALR2, and GALR3). The neuropeptide GAL regulates several physiological and pathophysiological functions in the central nervous system, the peripheral nervous system, and the peripheral organs. GAL is secreted mainly by oligodendrocytes, astrocytes, and the gastrointestinal tract, and its effect depends on the interaction with its different receptors. These receptors are expressed mainly in the central, peripheral nervous systems and the intestines. OBJECTIVE The present review evaluates the role of GAL family in inflammatory diseases. An overview is given of the signaling and pharmacological effects due to the interaction between GAL and GALR in different cell types. The potential use of GAL as a therapeutic resource is critically discussed. CONCLUSION GAL is suggested to have an anti-inflammatory function in some situations and a proinflammatory function in others. The literature on GAL is controversial and currently not conclusive. This could be due to the complexity of the metabolic network signaling induced by the interactions between GAL and GALR. In the next future, GAL might be a promising therapeutic resource for several diseases, but its practical use for disease control is presently not advisable.
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Affiliation(s)
- Caroline Maria Oliveira Volpe
- Nucleo de Pos-Graduacao e Pesquisa, Hospital Santa Casa de Belo Horizonte, Rua Domingos Vieira 590, Santa Efigenia, 30150-240, Belo Horizonte, MG, Brazil
| | - Tatiana Vaz
- Nucleo de Pos-Graduacao e Pesquisa, Hospital Santa Casa de Belo Horizonte, Rua Domingos Vieira 590, Santa Efigenia, 30150-240, Belo Horizonte, MG, Brazil
| | - Fabiana Rocha-Silva
- Nucleo de Pos-Graduacao e Pesquisa, Hospital Santa Casa de Belo Horizonte, Rua Domingos Vieira 590, Santa Efigenia, 30150-240, Belo Horizonte, MG, Brazil
| | - Pedro Henrique Villar-Delfino
- Nucleo de Pos-Graduacao e Pesquisa, Hospital Santa Casa de Belo Horizonte, Rua Domingos Vieira 590, Santa Efigenia, 30150-240, Belo Horizonte, MG, Brazil
| | - José Augusto Nogueira-Machado
- Nucleo de Pos-Graduacao e Pesquisa, Hospital Santa Casa de Belo Horizonte, Rua Domingos Vieira 590, Santa Efigenia, 30150-240, Belo Horizonte, MG, Brazil
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Hu G, Yu S, Yuan C, Hong W, Wang Z, Zhang R, Wang D, Li Z, Yi Z, Fang Y. Gene expression signatures differentiating major depressive disorder from subsyndromal symptomatic depression. Aging (Albany NY) 2021; 13:13124-13137. [PMID: 33971621 PMCID: PMC8148500 DOI: 10.18632/aging.202995] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 03/27/2021] [Indexed: 12/11/2022]
Abstract
Subsyndromal symptomatic depression (SSD) and major depressive disorder (MDD) have been classified as distinct diseases, due to their dissimilar gene expression profiles and responses to venlafaxine. To identify specific biomarkers of these two diseases, we conducted a secondary analysis of the gene expression signatures of SSD patients, MDD patients and healthy controls (n=8/group) from the study of Yi et al. Global, individual, specific, enrichment and co-expression analyses were used to compare the transcriptomic profiles of peripheral blood lymphocytes from the three groups. The global and individual analyses revealed that different genes were up- and downregulated in the SSD and MDD groups. Through our specific analysis, we identified 1719 and 3278 differentially expressed genes specifically associated with MDD and SSD, respectively. Enrichment and co-expression analyses demonstrated that the genes specific to MDD were enriched in pathways associated with hormone levels and immune responses, while those specific to SSD were associated with immune function. The specific hub gene for the MDD co-expression network was transmembrane protein 132B (TMEM132B), while the hub genes for SSD were actin-related protein 2/3 complex (ARPC2) and solute carrier family 5 member 5 (SLC5A5). This bioinformatic analysis has provided potential biomarkers that can distinguish SSD from MDD.
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Affiliation(s)
- Guoqin Hu
- Clinical Research Center, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200030, China.,Department of Psychiatry, Huangpu District Mental Health Center, Shanghai 200023, China
| | - Shunying Yu
- Clinical Research Center, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200030, China
| | - Chengmei Yuan
- Clinical Research Center, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200030, China
| | - Wu Hong
- Clinical Research Center, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200030, China
| | - Zuowei Wang
- Department of Psychiatry, Hongkou District Mental Health Center, Shanghai 200083, China
| | - Ran Zhang
- Clinical Research Center, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200030, China
| | - Dongxiang Wang
- Clinical Research Center, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200030, China
| | - Zezhi Li
- Department of Neurology, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
| | - Zhenghui Yi
- Clinical Research Center, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200030, China
| | - Yiru Fang
- Clinical Research Center, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200030, China.,CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai 20000, China.,Shanghai Key Laboratory of Psychotic Disorders, Shanghai 201108, China
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Hu W, Fan X, Zhou B, Li L, Tian B, Fang X, Xu X, Liu H, Yang G, Liu Y. Circulating alarin concentrations are high in patients with type 2 diabetes and increased by glucagon-like peptide-1 receptor agonist treatment: An Consort-compliant study. Medicine (Baltimore) 2019; 98:e16428. [PMID: 31305464 PMCID: PMC6641675 DOI: 10.1097/md.0000000000016428] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
CONTEXT Alarin has been reported to be relative to food intake and an increase in body weight. However, to date, no report has demonstrated the relationship between circulating alarin and diabetes in humans. OBJECTIVE The objective of this study is to gain insight into the possible role of alarin in humans. DESIGN AND METHODS 164 patients with newly diagnosed type 2 diabetes mellitus (nT2DM), 112 IGT and 134 healthy subjects were recruited for this study. In an interventional study, 29 nT2DM patients were treated by a weekly GLP-1RA for 6 months. Plasma alarin concentrations were measured by ELISA. RESULTS Circulating alarin concentrations were significantly higher in both IGT and nT2DM subjects than in healthy individuals (0.40 ± 0.14 and 0.54 ± 0.24 vs 0.37 ± 0.10 μg/L, P < .05 or P < .01), whereas in T2DM patients, circulating alarin levels were higher than in IGT subjects. Circulating alarin positively correlated with FBG, HbA1c, HOMA-IR, AUCglucose and TNFα (P < .05 or P < .01). Multivariate logistic regression revealed that circulating alarin levels were correlated with IGT and T2DM. GLP-1RA treatment for 6 months increased circulating alarin levels in T2DM patients (from 0.34 ± 0.10 for baseline, to 0.39 ± 0.14 for 12 weeks, and finally to 0.38 ± 0.15 μg/L for 24 weeks; vs. pre-treatment P < .05). CONCLUSIONS These data suggest that alarin might be involved in the pathogenesis of T2DM in humans. CLINICAL TRIAL REGISTRATION NUMBER ChiCTR-OCS-13003185 (18/03/2013 ).
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Affiliation(s)
- Wenjing Hu
- Chongqing Prevention and Treatment Hospital for Occupational Diseases
| | - Xiaoyun Fan
- Chongqing Prevention and Treatment Hospital for Occupational Diseases
| | - Baoyong Zhou
- Department of Hepatobiliary Surgery, First Affiliated Hospital, Chongqing Medical University
| | - Ling Li
- Key Laboratory of Diagnostic Medicine (Ministry of Education) and Department of Clinical Biochemistry, College of Laboratory Medicine, Chongqing Medical University
| | - Bo Tian
- Chongqing Prevention and Treatment Hospital for Occupational Diseases
| | - Xia Fang
- Department of Endocrinology, The Second Affiliated Hospital, Chongqing Medical University and Chongqing Clinical Research Center for Geriatrics, Chongqing, China
| | - Xiaohui Xu
- Department of Endocrinology, The Second Affiliated Hospital, Chongqing Medical University and Chongqing Clinical Research Center for Geriatrics, Chongqing, China
| | - Hua Liu
- Department of Pediatrics, University of Mississippi Medical Center, Jackson, MS, USA
| | - Gangyi Yang
- Chongqing Prevention and Treatment Hospital for Occupational Diseases
- Department of Endocrinology, The Second Affiliated Hospital, Chongqing Medical University and Chongqing Clinical Research Center for Geriatrics, Chongqing, China
| | - Yongsheng Liu
- Chongqing Prevention and Treatment Hospital for Occupational Diseases
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Jabari S, Schrödl F, Kaser-Eichberger A, Kofler B, Brehmer A. Alarin in different human intestinal epithelial cell types. Histochem Cell Biol 2019; 151:513-520. [PMID: 30612153 DOI: 10.1007/s00418-018-1763-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/18/2018] [Indexed: 12/18/2022]
Abstract
Alarin (AL), a new member of the galanin family, has been localized in various CNS regions, mainly in rodents. Among other effects, it modulates food intake. Therefore, we analyzed the immunohistochemical distribution pattern of AL in human intestinal epithelia. Cryosections of 12 human bowel samples were immunohistochemically double-stained for AL and α-defensin 5 (αD; first set). Two further sets of sections were quadruple-stained either (second set) for AL, chromogranin (CG), synaptophysin (SY), and somatostatin (SO) or (third set) for AL, CG, Peptide Y (PY), and 5-hydroxytryptamine (5-HT). Slides were digitized and quantitative analysis of co-localization rates was undertaken. Small bowel: most of AL-positive cells (56%) were αD-positive Paneth cells located within the base of the crypts (first set). In the second set, about 27% of AL-labeled cells were co-reactive for SY and CG, likely representing entero-endocrine cells. In the third set, the largest subpopulation of AL-positive cells was not co-reactive for other markers applied (89%); most of them were likely Paneth cells. Large bowel: co-localization of AL with αD was not detected (first set). In the second set, AL was frequently co-localized with the other three markers applied (68%). In the third set, AL was frequently co-localized with 5-HT and CG (31%) as well as with PY and 5-HT (22%). Due to its presence in various enteroendocrine as well as Paneth cells, AL may be involved in different physiological and pathological processes.
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Affiliation(s)
- Samir Jabari
- Institute of Neuropathology, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany.
| | - Falk Schrödl
- Department of Ophthalmology/Optometry, Research Program Experimental Ophthalmology, Paracelsus Medical University, Salzburg, Austria.,Department of Anatomy, Paracelsus Medical University, Salzburg, Austria
| | - Alexandra Kaser-Eichberger
- Department of Ophthalmology/Optometry, Research Program Experimental Ophthalmology, Paracelsus Medical University, Salzburg, Austria.,Department of Anatomy, Paracelsus Medical University, Salzburg, Austria
| | - Barbara Kofler
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria
| | - Axel Brehmer
- Institute of Anatomy and Cell Biology, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
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Kaser-Eichberger A, Trost A, Strohmaier C, Bogner B, Runge C, Bruckner D, Hohberger B, Jünemann A, Kofler B, Reitsamer HA, Schrödl F. Distribution of the neuro-regulatory peptide galanin in the human eye. Neuropeptides 2017; 64:85-93. [PMID: 27914762 DOI: 10.1016/j.npep.2016.11.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 11/22/2016] [Accepted: 11/22/2016] [Indexed: 02/07/2023]
Abstract
Galanin (GAL) is a neuro-regulatory peptide involved in many physiological and pathophysiological processes. While data of GAL origin/distribution in the human eye are rather fragmentary and since recently the presence of GAL-receptors in the normal human eye has been reported, we here systematically search for sources of ocular GAL in the human eye. Human eyes (n=14) were prepared for single- and double-immunohistochemistry of GAL and neurofilaments (NF). Cross- and flat-mount sections were achieved; confocal laser-scanning microscopy was used for documentation. In the anterior eye, GAL-immunoreactivity (GAL-IR) was detected in basal layers of corneal epithelium, endothelium, and in nerve fibers and keratinocytes of the corneal stroma. In the conjunctiva, GAL-IR was seen throughout all epithelial cell layers. In the iris, sphincter and dilator muscle and endothelium of iris vessels displayed GAL-IR. It was also detected in stromal cells containing melanin granules, while these were absent in others. In the ciliary body, ciliary muscle and pigmented as well as non-pigmented ciliary epithelium displayed GAL-IR. In the retina, GAL-IR was detected in cells associated with the ganglion cell layer, and in endothelial cells of retinal blood vessels. In the choroid, nerve fibers of the choroidal stroma as well as fibers forming boutons and surrounding choroidal blood vessels displayed GAL-IR. Further, the majority of intrinsic choroidal neurons were GAL-positive, as revealed by co-localization-experiments with NF, while a minority displayed NF- or GAL-IR only. GAL-IR was also detected in choroidal melanocytes, as identified by the presence of intracellular melanin-granules, as well as in cells lacking melanin-granules, most likely representing macrophages. GAL-IR was detected in numerous cells and tissues throughout the anterior and posterior eye and might therefore be an important regulatory peptide for many aspects of ocular control. Upcoming studies in diseased tissue will help to clarify the role of GAL in ocular homeostasis.
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Affiliation(s)
- Alexandra Kaser-Eichberger
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, Salzburg, Austria.
| | - Andrea Trost
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, Salzburg, Austria
| | - Clemens Strohmaier
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, Salzburg, Austria
| | - Barbara Bogner
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, Salzburg, Austria
| | - Christian Runge
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, Salzburg, Austria
| | - Daniela Bruckner
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, Salzburg, Austria
| | - Bettina Hohberger
- Dept. of Ophthalmology, University Erlangen-Nuremberg, Erlangen, Germany
| | - Anselm Jünemann
- Dept. of Ophthalmology, University Rostock, Rostock, Germany
| | - Barbara Kofler
- Laura-Bassi Centre of Expertise, THERAPEP, Research Program of Receptor Biochemistry and Tumor Metabolism, Dept. of Pediatrics, Paracelsus Medical University/SALK, Salzburg, Austria
| | - Herbert A Reitsamer
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, Salzburg, Austria; Director of the Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, Salzburg, Austria
| | - Falk Schrödl
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, Salzburg, Austria; Dept. of Anatomy, Paracelsus Medical University, Salzburg, Austria
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Mikó A, Füredi N, Tenk J, Rostás I, Soós S, Solymár M, Székely M, Balaskó M, Brunner SM, Kofler B, Pétervári E. Acute central effects of alarin on the regulation on energy homeostasis. Neuropeptides 2017; 64:117-122. [PMID: 27625299 DOI: 10.1016/j.npep.2016.09.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 09/04/2016] [Indexed: 12/17/2022]
Abstract
Hypothalamic neuropeptides influence the main components of energy balance: metabolic rate, food intake, body weight as well as body temperature, by exerting either an overall anabolic or catabolic effect. The contribution of alarin, the most recently discovered member of the galanin peptide family to the regulation of energy metabolism has been suggested. Our aim was to analyze the complex thermoregulatory and food intake-related effects of alarin in rats. Adult male Wistar rats received different doses of alarin (0.3; 1; 3 and 15μg corresponding approximately to 0.1, 0.33, 1, and 5 nmol, respectively) intracerebroventricularly. Regarding thermoregulatory analysis, oxygen consumption (indicating metabolic rate), core temperature and heat loss (assessed by tail skin temperature) were recorded in an Oxymax indirect calorimeter system complemented with thermocouples and Benchtop thermometer. In order to investigate potential prostaglandin-mediated mechanisms of the hyperthermic effect of alarin, effects of intraperitoneally applied non-selective (indomethacin, 2mg/kg) or selective cyclooxygenase inhibitor (COX-2 inhibitor meloxicam, 1; 2mg/kg) were tested. Effects of alarin on daytime and nighttime spontaneous food intake, as well as, 24-h fasting-induced re-feeding were recorded in an automated FeedScale system. Alarin increased oxygen consumption with simultaneous suppression of heat loss leading to a slow coordinated rise in core temperature. Both applied COX-inhibitors suppressed this action. Alarin failed to induce daytime food intake, but suppressed spontaneous nighttime and also fasting-induced re-feeding food intake. Alarin appears to elicit a slow anorexigenic and prostaglandin-mediated, fever-like hyperthermic response in rats. Such a combination would characterize a catabolic mediator. The potential involvement of alarin in sickness behavior may be assumed.
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Affiliation(s)
- Alexandra Mikó
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - Nóra Füredi
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - Judit Tenk
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - Ildikó Rostás
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - Szilvia Soós
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - Margit Solymár
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - Miklós Székely
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - Márta Balaskó
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - Susanne M Brunner
- Laura Bassi Centre of Expertise - THERAPEP, Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria
| | - Barbara Kofler
- Laura Bassi Centre of Expertise - THERAPEP, Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria.
| | - Erika Pétervári
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary.
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10
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Intracerebroventricular Injection of Alarin Increased Glucose Uptake in Skeletal Muscle of Diabetic Rats. PLoS One 2015; 10:e0139327. [PMID: 26439383 PMCID: PMC4595443 DOI: 10.1371/journal.pone.0139327] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 09/11/2015] [Indexed: 12/18/2022] Open
Abstract
In order to investigate the central effect of alarin on glucose uptake, we administered alarin and/ or its inhibitor, ala6-25Cys into the cerebral ventricles of the type 2 diabetic rats. Then the relative parameters about glucose uptake in skeletal muscles were measured. We found that central treatment with alarin significantly increased the food intake, body weight and glucose infusion rates in hyperinsulinemic euglycemic clamp tests of the animals. Besides, the treatment also enhanced 2-deoxy-[3H]-D-glucose uptake, vesicle-associated membrane protein 2 contents, glucose transporter 4 protein and mRNA expression, as well as pAktThr308, pAktSer473 and total Akt levels in muscle cells, but reduced plasma glucose and insulin levels of the rats. All of the alarin-inducing events may be antagonised by central injection of ala6-25Cys. These results suggest that central administration of alarin stimulates glucose uptake mediated by activation of Akt signal pathway in type 2 diabetic animals.
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Lang R, Gundlach AL, Holmes FE, Hobson SA, Wynick D, Hökfelt T, Kofler B. Physiology, signaling, and pharmacology of galanin peptides and receptors: three decades of emerging diversity. Pharmacol Rev 2015; 67:118-75. [PMID: 25428932 DOI: 10.1124/pr.112.006536] [Citation(s) in RCA: 218] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Galanin was first identified 30 years ago as a "classic neuropeptide," with actions primarily as a modulator of neurotransmission in the brain and peripheral nervous system. Other structurally-related peptides-galanin-like peptide and alarin-with diverse biologic actions in brain and other tissues have since been identified, although, unlike galanin, their cognate receptors are currently unknown. Over the last two decades, in addition to many neuronal actions, a number of nonneuronal actions of galanin and other galanin family peptides have been described. These include actions associated with neural stem cells, nonneuronal cells in the brain such as glia, endocrine functions, effects on metabolism, energy homeostasis, and paracrine effects in bone. Substantial new data also indicate an emerging role for galanin in innate immunity, inflammation, and cancer. Galanin has been shown to regulate its numerous physiologic and pathophysiological processes through interactions with three G protein-coupled receptors, GAL1, GAL2, and GAL3, and signaling via multiple transduction pathways, including inhibition of cAMP/PKA (GAL1, GAL3) and stimulation of phospholipase C (GAL2). In this review, we emphasize the importance of novel galanin receptor-specific agonists and antagonists. Also, other approaches, including new transgenic mouse lines (such as a recently characterized GAL3 knockout mouse) represent, in combination with viral-based techniques, critical tools required to better evaluate galanin system physiology. These in turn will help identify potential targets of the galanin/galanin-receptor systems in a diverse range of human diseases, including pain, mood disorders, epilepsy, neurodegenerative conditions, diabetes, and cancer.
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Affiliation(s)
- Roland Lang
- Department of Dermatology (R.L.) and Laura Bassi Centre of Expertise, Department of Pediatrics (B.K.), Paracelsus Private Medical University, Salzburg, Austria; The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia (A.L.G.); Schools of Physiology and Pharmacology and Clinical Sciences, Bristol University, Bristol, United Kingdom (F.E.H., S.A.H., D.W.); and Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (T.H.)
| | - Andrew L Gundlach
- Department of Dermatology (R.L.) and Laura Bassi Centre of Expertise, Department of Pediatrics (B.K.), Paracelsus Private Medical University, Salzburg, Austria; The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia (A.L.G.); Schools of Physiology and Pharmacology and Clinical Sciences, Bristol University, Bristol, United Kingdom (F.E.H., S.A.H., D.W.); and Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (T.H.)
| | - Fiona E Holmes
- Department of Dermatology (R.L.) and Laura Bassi Centre of Expertise, Department of Pediatrics (B.K.), Paracelsus Private Medical University, Salzburg, Austria; The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia (A.L.G.); Schools of Physiology and Pharmacology and Clinical Sciences, Bristol University, Bristol, United Kingdom (F.E.H., S.A.H., D.W.); and Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (T.H.)
| | - Sally A Hobson
- Department of Dermatology (R.L.) and Laura Bassi Centre of Expertise, Department of Pediatrics (B.K.), Paracelsus Private Medical University, Salzburg, Austria; The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia (A.L.G.); Schools of Physiology and Pharmacology and Clinical Sciences, Bristol University, Bristol, United Kingdom (F.E.H., S.A.H., D.W.); and Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (T.H.)
| | - David Wynick
- Department of Dermatology (R.L.) and Laura Bassi Centre of Expertise, Department of Pediatrics (B.K.), Paracelsus Private Medical University, Salzburg, Austria; The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia (A.L.G.); Schools of Physiology and Pharmacology and Clinical Sciences, Bristol University, Bristol, United Kingdom (F.E.H., S.A.H., D.W.); and Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (T.H.)
| | - Tomas Hökfelt
- Department of Dermatology (R.L.) and Laura Bassi Centre of Expertise, Department of Pediatrics (B.K.), Paracelsus Private Medical University, Salzburg, Austria; The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia (A.L.G.); Schools of Physiology and Pharmacology and Clinical Sciences, Bristol University, Bristol, United Kingdom (F.E.H., S.A.H., D.W.); and Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (T.H.)
| | - Barbara Kofler
- Department of Dermatology (R.L.) and Laura Bassi Centre of Expertise, Department of Pediatrics (B.K.), Paracelsus Private Medical University, Salzburg, Austria; The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia (A.L.G.); Schools of Physiology and Pharmacology and Clinical Sciences, Bristol University, Bristol, United Kingdom (F.E.H., S.A.H., D.W.); and Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (T.H.)
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Guo L, Fang P, Yu M, Shi M, Bo P, Zhang Z. Central alarin ameliorated insulin resistance of adipocytes in type 2 diabetic rats. J Endocrinol 2014; 223:217-25. [PMID: 25240061 DOI: 10.1530/joe-14-0102] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Alarin, a regulatory peptide, belongs to the galanin family and plays the same regulatory roles as galanin in orexigenic activity and energy metabolism. Our previous studies had found that galanin might facilitate insulin sensitivity via activation of its central receptors. To date, little is known about whether central alarin may exert similar effects on insulin sensitivity. In order to investigate this, alarin and its specific antagonist, alarin 6-25Cys, were administered into the cerebral ventricles of type 2 diabetic rats (T2DR) to evaluate the changes in insulin resistance. The results indicated that central treatment with alarin significantly increased the body weight of animals, the 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose uptake, the plasma adiponectin levels, the glucose infusion rates in hyperinsulinemic-euglycemic clamp tests, the vesicle-associated membrane protein 2 as well as glucose transporter 4 (GLUT4 (SLC2A4)) protein and mRNA levels, and the ratios of GLUT4 contents in plasma membranes to total cell membranes in adipocytes, but reduced blood glucose and plasma retinol-binding protein 4 levels. These effects of alarin may be inhibited by pretreatment with alarin 6-25Cys. The above-mentioned results suggest that the central alarin projective system may facilitate insulin sensitivity and glucose uptake via the increase in GLUT4 content and GLUT4 translocation from intracellular pools to plasma membranes in T2DR.
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Affiliation(s)
- Lili Guo
- Department of EndocrinologyClinical Medical College, Yangzhou University, Nantong West Street No. 98, Yangzhou, Jiangsu 225001, ChinaMedical CollegeResearch Institute of Combined Chinese Traditional and Western Medicine, Yangzhou University, Yangzhou, Jiangsu 225001, ChinaDepartment of PhysiologyHanlin College, Nanjing University of Chinese Medicine, Taizhou, Jiangsu 225300, ChinaDepartment of Physical EducationChuzhou College, Chuzhou, Anhui Province 239012, China
| | - Penghua Fang
- Department of EndocrinologyClinical Medical College, Yangzhou University, Nantong West Street No. 98, Yangzhou, Jiangsu 225001, ChinaMedical CollegeResearch Institute of Combined Chinese Traditional and Western Medicine, Yangzhou University, Yangzhou, Jiangsu 225001, ChinaDepartment of PhysiologyHanlin College, Nanjing University of Chinese Medicine, Taizhou, Jiangsu 225300, ChinaDepartment of Physical EducationChuzhou College, Chuzhou, Anhui Province 239012, China
| | - Mei Yu
- Department of EndocrinologyClinical Medical College, Yangzhou University, Nantong West Street No. 98, Yangzhou, Jiangsu 225001, ChinaMedical CollegeResearch Institute of Combined Chinese Traditional and Western Medicine, Yangzhou University, Yangzhou, Jiangsu 225001, ChinaDepartment of PhysiologyHanlin College, Nanjing University of Chinese Medicine, Taizhou, Jiangsu 225300, ChinaDepartment of Physical EducationChuzhou College, Chuzhou, Anhui Province 239012, China
| | - Mingyi Shi
- Department of EndocrinologyClinical Medical College, Yangzhou University, Nantong West Street No. 98, Yangzhou, Jiangsu 225001, ChinaMedical CollegeResearch Institute of Combined Chinese Traditional and Western Medicine, Yangzhou University, Yangzhou, Jiangsu 225001, ChinaDepartment of PhysiologyHanlin College, Nanjing University of Chinese Medicine, Taizhou, Jiangsu 225300, ChinaDepartment of Physical EducationChuzhou College, Chuzhou, Anhui Province 239012, China
| | - Ping Bo
- Department of EndocrinologyClinical Medical College, Yangzhou University, Nantong West Street No. 98, Yangzhou, Jiangsu 225001, ChinaMedical CollegeResearch Institute of Combined Chinese Traditional and Western Medicine, Yangzhou University, Yangzhou, Jiangsu 225001, ChinaDepartment of PhysiologyHanlin College, Nanjing University of Chinese Medicine, Taizhou, Jiangsu 225300, ChinaDepartment of Physical EducationChuzhou College, Chuzhou, Anhui Province 239012, China Department of EndocrinologyClinical Medical College, Yangzhou University, Nantong West Street No. 98, Yangzhou, Jiangsu 225001, ChinaMedical CollegeResearch Institute of Combined Chinese Traditional and Western Medicine, Yangzhou University, Yangzhou, Jiangsu 225001, ChinaDepartment of PhysiologyHanlin College, Nanjing University of Chinese Medicine, Taizhou, Jiangsu 225300, ChinaDepartment of Physical EducationChuzhou College, Chuzhou, Anhui Province 239012, China
| | - Zhenwen Zhang
- Department of EndocrinologyClinical Medical College, Yangzhou University, Nantong West Street No. 98, Yangzhou, Jiangsu 225001, ChinaMedical CollegeResearch Institute of Combined Chinese Traditional and Western Medicine, Yangzhou University, Yangzhou, Jiangsu 225001, ChinaDepartment of PhysiologyHanlin College, Nanjing University of Chinese Medicine, Taizhou, Jiangsu 225300, ChinaDepartment of Physical EducationChuzhou College, Chuzhou, Anhui Province 239012, China
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13
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Wang M, Chen Q, Li M, Zhou W, Ma T, Wang Y, Gu S. Alarin-induced antidepressant-like effects and their relationship with hypothalamus-pituitary-adrenal axis activity and brain derived neurotrophic factor levels in mice. Peptides 2014; 56:163-72. [PMID: 24768903 DOI: 10.1016/j.peptides.2014.04.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 04/11/2014] [Accepted: 04/11/2014] [Indexed: 12/22/2022]
Abstract
Alarin is a newly identified member of the galanin family of peptides. Galanin has been shown to exert regulatory effects on depression. Similar to galanin in distribution, alarin is also expressed in the medial amygdala and hypothalamus, i.e., regions interrelated with depression. However, it remains a puzzle whether alarin is involved in depression. Accordingly, we established the depression-like mouse model using behavioral tests to ascertain the possible involvement of alarin, with fluoxetine as a positive control. With the positive antidepressant-like effects of alarin, we further examined its relationship to HPA axis activity and brain-derived neurotrophic factor (BDNF) levels in different brain areas in a chronic unpredictable mild stress (CUMS) paradigm. In the acute studies, alarin produced a dose-related reduction in the immobility duration in tail suspension test (TST) in mice. In the open-field test, intracerebroventricular (i.c.v.) injection of alarin (1.0 nmol) did not impair locomotion or motor coordination in the treated mice. In the CUMS paradigm, alarin administration (1.0 nmol, i.c.v.) significantly improved murine behaviors (FST and locomotor activity), which was associated with a decrease in corticotropin-releasing hormone (CRH) mRNA levels in the hypothalamus, as well as a decline in serum levels of CRH, adrenocorticotropic hormone (ACTH) and corticosterone (CORT), all of which are key hormones of the HPA axis. Furthermore, alarin upregulated BDNF mRNA levels in the prefrontal cortex and hippocampus. These findings suggest that alarin may potentiate the development of new antidepressants, which would be further secured with the identification of its receptor(s).
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Affiliation(s)
- Ming Wang
- Department of Pharmacology, Xuzhou Medical College, Xuzhou, Jiangsu 221004, China
| | - Qian Chen
- Department of Pharmacology, Xuzhou Medical College, Xuzhou, Jiangsu 221004, China
| | - Mei Li
- Department of Pharmacology, Xuzhou Medical College, Xuzhou, Jiangsu 221004, China
| | - Wei Zhou
- Department of Pharmacology, Xuzhou Medical College, Xuzhou, Jiangsu 221004, China
| | - Tengfei Ma
- Department of Pharmacology, Xuzhou Medical College, Xuzhou, Jiangsu 221004, China
| | - Yun Wang
- Department of Pharmacology, Xuzhou Medical College, Xuzhou, Jiangsu 221004, China
| | - Shuling Gu
- Department of Pharmacology, Xuzhou Medical College, Xuzhou, Jiangsu 221004, China.
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14
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Wang G. Human antimicrobial peptides and proteins. Pharmaceuticals (Basel) 2014; 7:545-94. [PMID: 24828484 PMCID: PMC4035769 DOI: 10.3390/ph7050545] [Citation(s) in RCA: 337] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 04/15/2014] [Accepted: 04/29/2014] [Indexed: 12/11/2022] Open
Abstract
As the key components of innate immunity, human host defense antimicrobial peptides and proteins (AMPs) play a critical role in warding off invading microbial pathogens. In addition, AMPs can possess other biological functions such as apoptosis, wound healing, and immune modulation. This article provides an overview on the identification, activity, 3D structure, and mechanism of action of human AMPs selected from the antimicrobial peptide database. Over 100 such peptides have been identified from a variety of tissues and epithelial surfaces, including skin, eyes, ears, mouths, gut, immune, nervous and urinary systems. These peptides vary from 10 to 150 amino acids with a net charge between -3 and +20 and a hydrophobic content below 60%. The sequence diversity enables human AMPs to adopt various 3D structures and to attack pathogens by different mechanisms. While α-defensin HD-6 can self-assemble on the bacterial surface into nanonets to entangle bacteria, both HNP-1 and β-defensin hBD-3 are able to block cell wall biosynthesis by binding to lipid II. Lysozyme is well-characterized to cleave bacterial cell wall polysaccharides but can also kill bacteria by a non-catalytic mechanism. The two hydrophobic domains in the long amphipathic α-helix of human cathelicidin LL-37 lays the basis for binding and disrupting the curved anionic bacterial membrane surfaces by forming pores or via the carpet model. Furthermore, dermcidin may serve as ion channel by forming a long helix-bundle structure. In addition, the C-type lectin RegIIIα can initially recognize bacterial peptidoglycans followed by pore formation in the membrane. Finally, histatin 5 and GAPDH(2-32) can enter microbial cells to exert their effects. It appears that granulysin enters cells and kills intracellular pathogens with the aid of pore-forming perforin. This arsenal of human defense proteins not only keeps us healthy but also inspires the development of a new generation of personalized medicine to combat drug-resistant superbugs, fungi, viruses, parasites, or cancer. Alternatively, multiple factors (e.g., albumin, arginine, butyrate, calcium, cyclic AMP, isoleucine, short-chain fatty acids, UV B light, vitamin D, and zinc) are able to induce the expression of antimicrobial peptides, opening new avenues to the development of anti-infectious drugs.
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Affiliation(s)
- Guangshun Wang
- Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center, 986495 Nebraska Medical Center, Omaha, NE 68198-6495, USA.
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15
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Database-Guided Discovery of Potent Peptides to Combat HIV-1 or Superbugs. Pharmaceuticals (Basel) 2013; 6:728-58. [PMID: 24276259 PMCID: PMC3816732 DOI: 10.3390/ph6060728] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 05/02/2013] [Accepted: 05/13/2013] [Indexed: 11/17/2022] Open
Abstract
Antimicrobial peptides (AMPs), small host defense proteins, are indispensable for the protection of multicellular organisms such as plants and animals from infection. The number of AMPs discovered per year increased steadily since the 1980s. Over 2,000 natural AMPs from bacteria, protozoa, fungi, plants, and animals have been registered into the antimicrobial peptide database (APD). The majority of these AMPs (>86%) possess 11–50 amino acids with a net charge from 0 to +7 and hydrophobic percentages between 31–70%. This article summarizes peptide discovery on the basis of the APD. The major methods are the linguistic model, database screening, de novo design, and template-based design. Using these methods, we identified various potent peptides against human immunodeficiency virus type 1 (HIV-1) or methicillin-resistant Staphylococcus aureus (MRSA). While the stepwise designed anti-HIV peptide is disulfide-linked and rich in arginines, the ab initio designed anti-MRSA peptide is linear and rich in leucines. Thus, there are different requirements for antiviral and antibacterial peptides, which could kill pathogens via different molecular targets. The biased amino acid composition in the database-designed peptides, or natural peptides such as θ-defensins, requires the use of the improved two-dimensional NMR method for structural determination to avoid the publication of misleading structure and dynamics. In the case of human cathelicidin LL-37, structural determination requires 3D NMR techniques. The high-quality structure of LL-37 provides a solid basis for understanding its interactions with membranes of bacteria and other pathogens. In conclusion, the APD database is a comprehensive platform for storing, classifying, searching, predicting, and designing potent peptides against pathogenic bacteria, viruses, fungi, parasites, and cancer cells.
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