1
|
Cell-Penetrating Peptides and Transportan. Pharmaceutics 2021; 13:pharmaceutics13070987. [PMID: 34210007 PMCID: PMC8308968 DOI: 10.3390/pharmaceutics13070987] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/24/2021] [Accepted: 06/25/2021] [Indexed: 12/21/2022] Open
Abstract
In the most recent 25–30 years, multiple novel mechanisms and applications of cell-penetrating peptides (CPP) have been demonstrated, leading to novel drug delivery systems. In this review, I present a brief introduction to the CPP area with selected recent achievements. This is followed by a nostalgic journey into the research in my own laboratories, which lead to multiple CPPs, starting from transportan and paving a way to CPP-based therapeutic developments in the delivery of bio-functional materials, such as peptides, proteins, vaccines, oligonucleotides and small molecules, etc.
Collapse
|
2
|
Nordin F, Ahmad RNR, Farzaneh F. Transactivator protein: An alternative for delivery of recombinant proteins for safer reprogramming of induced Pluripotent Stem Cell. Virus Res 2017; 235:106-114. [DOI: 10.1016/j.virusres.2017.04.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 04/08/2017] [Indexed: 10/19/2022]
|
3
|
Rahimi M, Vinciguerra M, Daghighi M, Özcan B, Akbarkhanzadeh V, Sheedfar F, Amini M, Mazza T, Pazienza V, Motazacker MM, Mahmoudi M, De Rooij FWM, Sijbrands E, Peppelenbosch MP, Rezaee F. Age-related obesity and type 2 diabetes dysregulate neuronal associated genes and proteins in humans. Oncotarget 2016; 6:29818-32. [PMID: 26337083 PMCID: PMC4745765 DOI: 10.18632/oncotarget.4904] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2015] [Accepted: 08/07/2015] [Indexed: 12/29/2022] Open
Abstract
Despite numerous developed drugs based on glucose metabolism interventions for treatment of age-related diseases such as diabetes neuropathies (DNs), DNs are still increasing in patients with type 1 or type 2 diabetes (T1D, T2D). We aimed to identify novel candidates in adipose tissue (AT) and pancreas with T2D for targeting to develop new drugs for DNs therapy. AT-T2D displayed 15 (e.g. SYT4 up-regulated and VGF down-regulated) and pancreas-T2D showed 10 (e.g. BAG3 up-regulated, VAV3 and APOA1 down-regulated) highly differentially expressed genes with neuronal functions as compared to control tissues. ELISA was blindly performed to measure proteins of 5 most differentially expressed genes in 41 human subjects. SYT4 protein was upregulated, VAV3 and APOA1 were down-regulated, and BAG3 remained unchanged in 1- Obese and 2- Obese-T2D without insulin, VGF protein was higher in these two groups as well as in group 3- Obese-T2D receiving insulin than 4-lean subjects. Interaction networks analysis of these 5 genes showed several metabolic pathways (e.g. lipid metabolism and insulin signaling). Pancreas is a novel site for APOA1 synthesis. VGF is synthesized in AT and could be considered as good diagnostic, and even prognostic, marker for age-induced diseases obesity and T2D. This study provides new targets for rational drugs development for the therapy of age-related DNs.
Collapse
Affiliation(s)
- Mehran Rahimi
- Faculty of Medical Science, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Manlio Vinciguerra
- Institute for Liver and Digestive Health, Division of Medicine, University College London (UCL), London, UK.,Gastroenterology Unit, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Mojtaba Daghighi
- Department of Biomedical Engineering, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Behiye Özcan
- Department of Endocrinology, Erasmus Medical Center, Rotterdam, The Netherlands
| | | | - Fareeba Sheedfar
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Marzyeh Amini
- Department of Epidemiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Tommaso Mazza
- Bioinformatics Unit, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Valerio Pazienza
- Gastroenterology Unit, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Mahdi M Motazacker
- Department of Clinical Genetics, Academic Medical Center, Amsterdam, The Netherlands
| | - Morteza Mahmoudi
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, United States.,Department of Nanotechnology and Nanotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
| | - Felix W M De Rooij
- Department of Cardiovascular Genetics, Metabolism, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Eric Sijbrands
- Department of Cardiovascular Genetics, Metabolism, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Maikel P Peppelenbosch
- Department of Gastroenterology and Hepatology, Erasmus Medical Center, University of Rotterdam, Rotterdam, The Netherlands
| | - Farhad Rezaee
- Department of Gastroenterology and Hepatology, Erasmus Medical Center, University of Rotterdam, Rotterdam, The Netherlands.,Department of Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| |
Collapse
|
4
|
Shim YJ, Kim JE, Hwang SK, Choi BS, Choi BH, Cho EM, Jang KM, Ko CW. Identification of Candidate Gene Variants in Korean MODY Families by Whole-Exome Sequencing. Horm Res Paediatr 2016; 83:242-51. [PMID: 25765181 DOI: 10.1159/000368657] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 09/22/2014] [Indexed: 12/15/2022] Open
Abstract
AIMS To date, 13 genes causing maturity-onset diabetes of the young (MODY) have been identified. However, there is a big discrepancy in the genetic locus between Asian and Caucasian patients with MODY. Thus, we conducted whole-exome sequencing in Korean MODY families to identify causative gene variants. METHODS Six MODY probands and their family members were included. Variants in the dbSNP135 and TIARA databases for Koreans and the variants with minor allele frequencies >0.5% of the 1000 Genomes database were excluded. We selected only the functional variants (gain of stop codon, frameshifts and nonsynonymous single-nucleotide variants) and conducted a case-control comparison in the family members. The selected variants were scanned for the previously introduced gene set implicated in glucose metabolism. RESULTS Three variants c.620C>T:p.Thr207Ile in PTPRD, c.559C>G:p.Gln187Glu in SYT9, and c.1526T>G:p.Val509Gly in WFS1 were respectively identified in 3 families. We could not find any disease-causative alleles of known MODY 1-13 genes. Based on the predictive program, Thr207Ile in PTPRD was considered pathogenic. CONCLUSIONS Whole-exome sequencing is a valuable method for the genetic diagnosis of MODY. Further evaluation is necessary about the role of PTPRD, SYT9 and WFS1 in normal insulin release from pancreatic beta cells.
Collapse
Affiliation(s)
- Ye Jee Shim
- Department of Pediatrics, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | | | | | | | | | | | | | | |
Collapse
|
5
|
Abstract
The prevalence of diabetes is increasing rapidly worldwide. A cardinal feature of most forms of diabetes is the lack of insulin-producing capability, due to the loss of insulin-producing β-cells, impaired glucose-sensitive insulin secretion from the β-cell, or a combination thereof, the reasons for which largely remain elusive. Reversible phosphorylation is an important and versatile mechanism for regulating the biological activity of many intracellular proteins, which, in turn, controls a variety of cellular functions. For instance, significant changes in protein kinase activities and in protein phosphorylation patterns occur subsequent to the stimulation of insulin release by glucose. Therefore, the molecular mechanisms regulating the phosphorylation of proteins involved in the insulin secretory process by the β-cell have been extensively investigated. However, far less is known about the role and regulation of protein dephosphorylation by various protein phosphatases. Herein, we review extant data implicating serine/threonine and tyrosine phosphatases in various aspects of healthy and diabetic islet biology, ranging from control of hormonal stimulus-secretion coupling to mitogenesis and apoptosis.
Collapse
Affiliation(s)
- Henrik Ortsäter
- Biovation Park TelgeSödertälje, SwedenResearch UnitSödertälje Hospital, SE-152 86 Södertälje, SwedenDegenerative Disease ProgramSanford-Burnham Medical Research Institute, Del E. Webb Neuroscience, Aging and Stem Cell Research Center, 10901 North Torrey Pines Road, La Jolla, California 92037, USADepartment of Biochemistry and Molecular BiologyCollege of Medicine, University of South Alabama, Mobile, Alabama 36688, USADepartment of Internal MedicineSödertälje Hospital, Södertälje, SwedenBiovation Park TelgeSödertälje, SwedenResearch UnitSödertälje Hospital, SE-152 86 Södertälje, SwedenDegenerative Disease ProgramSanford-Burnham Medical Research Institute, Del E. Webb Neuroscience, Aging and Stem Cell Research Center, 10901 North Torrey Pines Road, La Jolla, California 92037, USADepartment of Biochemistry and Molecular BiologyCollege of Medicine, University of South Alabama, Mobile, Alabama 36688, USADepartment of Internal MedicineSödertälje Hospital, Södertälje, Sweden
| | - Nina Grankvist
- Biovation Park TelgeSödertälje, SwedenResearch UnitSödertälje Hospital, SE-152 86 Södertälje, SwedenDegenerative Disease ProgramSanford-Burnham Medical Research Institute, Del E. Webb Neuroscience, Aging and Stem Cell Research Center, 10901 North Torrey Pines Road, La Jolla, California 92037, USADepartment of Biochemistry and Molecular BiologyCollege of Medicine, University of South Alabama, Mobile, Alabama 36688, USADepartment of Internal MedicineSödertälje Hospital, Södertälje, Sweden
| | - Richard E Honkanen
- Biovation Park TelgeSödertälje, SwedenResearch UnitSödertälje Hospital, SE-152 86 Södertälje, SwedenDegenerative Disease ProgramSanford-Burnham Medical Research Institute, Del E. Webb Neuroscience, Aging and Stem Cell Research Center, 10901 North Torrey Pines Road, La Jolla, California 92037, USADepartment of Biochemistry and Molecular BiologyCollege of Medicine, University of South Alabama, Mobile, Alabama 36688, USADepartment of Internal MedicineSödertälje Hospital, Södertälje, Sweden
| | - Åke Sjöholm
- Biovation Park TelgeSödertälje, SwedenResearch UnitSödertälje Hospital, SE-152 86 Södertälje, SwedenDegenerative Disease ProgramSanford-Burnham Medical Research Institute, Del E. Webb Neuroscience, Aging and Stem Cell Research Center, 10901 North Torrey Pines Road, La Jolla, California 92037, USADepartment of Biochemistry and Molecular BiologyCollege of Medicine, University of South Alabama, Mobile, Alabama 36688, USADepartment of Internal MedicineSödertälje Hospital, Södertälje, SwedenBiovation Park TelgeSödertälje, SwedenResearch UnitSödertälje Hospital, SE-152 86 Södertälje, SwedenDegenerative Disease ProgramSanford-Burnham Medical Research Institute, Del E. Webb Neuroscience, Aging and Stem Cell Research Center, 10901 North Torrey Pines Road, La Jolla, California 92037, USADepartment of Biochemistry and Molecular BiologyCollege of Medicine, University of South Alabama, Mobile, Alabama 36688, USADepartment of Internal MedicineSödertälje Hospital, Södertälje, SwedenBiovation Park TelgeSödertälje, SwedenResearch UnitSödertälje Hospital, SE-152 86 Södertälje, SwedenDegenerative Disease ProgramSanford-Burnham Medical Research Institute, Del E. Webb Neuroscience, Aging and Stem Cell Research Center, 10901 North Torrey Pines Road, La Jolla, California 92037, USADepartment of Biochemistry and Molecular BiologyCollege of Medicine, University of South Alabama, Mobile, Alabama 36688, USADepartment of Internal MedicineSödertälje Hospital, Södertälje, Sweden
| |
Collapse
|
6
|
Therapeutic properties of VO(dmpp)2 as assessed by in vitro and in vivo studies in type 2 diabetic GK rats. J Inorg Biochem 2014; 131:115-22. [DOI: 10.1016/j.jinorgbio.2013.11.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 11/15/2013] [Accepted: 11/17/2013] [Indexed: 01/28/2023]
|
7
|
Exploring transduction mechanisms of protein transduction domains (PTDs) in living cells utilizing single-quantum dot tracking (SQT) technology. SENSORS 2012; 12:549-72. [PMID: 22368485 PMCID: PMC3279229 DOI: 10.3390/s120100549] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 12/30/2011] [Accepted: 12/31/2011] [Indexed: 12/04/2022]
Abstract
Specific protein domains known as protein transduction domains (PTDs) can permeate cell membranes and deliver proteins or bioactive materials into living cells. Various approaches have been applied for improving their transduction efficacy. It is, therefore, crucial to clarify the entry mechanisms and to identify the rate-limiting steps. Because of technical limitations for imaging PTD behavior on cells with conventional fluorescent-dyes, how PTDs enter the cells has been a topic of much debate. Utilizing quantum dots (QDs), we recently tracked the behavior of PTD that was derived from HIV-1 Tat (TatP) in living cells at the single-molecule level with 7-nm special precision. In this review article, we initially summarize the controversy on TatP entry mechanisms; thereafter, we will focus on our recent findings on single-TatP-QD tracking (SQT), to identify the major sequential steps of intracellular delivery in living cells and to discuss how SQT can easily provide direct information on TatP entry mechanisms. As a primer for SQT study, we also discuss the latest findings on single particle tracking of various molecules on the plasma membrane. Finally, we discuss the problems of QDs and the challenges for the future in utilizing currently available QD probes for SQT. In conclusion, direct identification of the rate-limiting steps of PTD entry with SQT should dramatically improve the methods for enhancing transduction efficiency.
Collapse
|
8
|
Portha B, Giroix MH, Tourrel-Cuzin C, Le-Stunff H, Movassat J. The GK rat: a prototype for the study of non-overweight type 2 diabetes. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2012; 933:125-59. [PMID: 22893405 DOI: 10.1007/978-1-62703-068-7_9] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Type 2 diabetes mellitus (T2D) arises when the endocrine pancreas fails to secrete sufficient insulin to cope with the metabolic demand because of β-cell secretory dysfunction and/or decreased β-cell mass. Defining the nature of the pancreatic islet defects present in T2D has been difficult, in part because human islets are inaccessible for direct study. This review is aimed to illustrate to what extent the Goto Kakizaki rat, one of the best characterized animal models of spontaneous T2D, has proved to be a valuable tool offering sufficient commonalities to study this aspect. A comprehensive compendium of the multiple functional GK abnormalities so far identified is proposed in this perspective, together with their time-course and interactions. A special focus is given toward the pathogenesis of defective β-cell number and function in the GK model. It is proposed that the development of T2D in the GK model results from the complex interaction of multiple events: (1) several susceptibility loci containing genes responsible for some diabetic traits; (2) gestational metabolic impairment inducing an epigenetic programming of the offspring pancreas and the major insulin target tissues; and (3) environmentally induced loss of β-cell differentiation due to chronic exposure to hyperglycemia/hyperlipidemia, inflammation, and oxidative stress.
Collapse
Affiliation(s)
- Bernard Portha
- Laboratoire B2PE (Biologie et Pathologie du Pancréas Endocrine), Unité BFA (Biologie Fonctionnelle et Adaptive), Université Paris-Diderot, CNRS EAC 4413, Paris, France.
| | | | | | | | | |
Collapse
|
9
|
Izuchi R, Nakai Y, Takahashi H, Ushiama S, Okada S, Misaka T, Abe K. Hepatic gene expression of the insulin signaling pathway is altered by administration of persimmon peel extract: a DNA microarray study using type 2 diabetic Goto-Kakizaki rats. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2011; 59:3320-3329. [PMID: 21370910 DOI: 10.1021/jf102422z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Persimmon (Diospyros kaki) is a very popular fruit in East Asian countries, but its peels are not consumed despite the fact that they contain many antioxidants such as carotenoids and polyphenols. We prepared a fat-soluble extract from persimmon peel (PP) and fed type 2 diabetic Goto-Kakizaki (GK) rats an AIN-93G rodent diet supplemented with persimmon peel extract (PP diet) for 12 weeks. Compared with the control AIN-93G diet, the PP diet significantly reduced plasma glutamic-pyruvate transaminase activity, with accumulation of β-cryptoxanthin in the liver. DNA microarray analysis revealed that the PP diet altered hepatic gene expression profiles. In particular, expression of insulin signaling pathway-related genes was significantly enriched in differentially expressed gene sets. Moreover, Western blotting analysis showed an increase in insulin receptor beta tyrosine phosphorylation in rats fed the PP diet. These data suggest that the PP diet improves insulin resistance in GK rats.
Collapse
Affiliation(s)
- Ryoichi Izuchi
- Toyo Institute of Food Technology, Kawanishi-shi, Hyogo, Japan.
| | | | | | | | | | | | | |
Collapse
|
10
|
Noguchi H, Matsushita M, Kobayashi N, Levy MF, Matsumoto S. Recent Advances in Protein Transduction Technology. Cell Transplant 2010; 19:649-54. [DOI: 10.3727/096368910x508744] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
During the past 15 years, a variety of peptides, known as protein transduction domains (PTDs), or cell-penetrating peptides (CPPs), have been characterized for their ability to translocate into live cells. There are now numerous examples of biologically active full-length proteins and peptides that have been successfully delivered to cells and tissues, both in vitro and in vivo. One of the principal mechanisms of protein transduction is via electrostatic interactions with the plasma membrane, subsequent penetration into the cells by macropinocytosis, and release into the cytoplasm and nuclei by retrograde transport. Recent reports have also now shown that some of the limitations of protein transduction technology have been overcome. In particular, the use of ubiquitination-resistant proteins has been demonstrated to be a more effective strategy for transduction because the half-life of these molecules is significantly increased. Moreover, the use of the NH2-terminal domain of the influenza virus hemagglutinin-2 subunit (HA2) or photosensitive PTDs has been shown to specifically enhance macropinosome escape. Hence, these and other recent advances in protein transduction technologies have created a number of possibilities for the development of new peptide-based drugs.
Collapse
Affiliation(s)
- Hirofumi Noguchi
- Baylor All Saints Medical Center, Baylor Research Institute, Fort Worth, TX, USA
| | | | - Naoya Kobayashi
- Department of Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Marlon F. Levy
- Baylor All Saints Medical Center, Baylor Research Institute, Fort Worth, TX, USA
| | - Shinichi Matsumoto
- Baylor All Saints Medical Center, Baylor Research Institute, Fort Worth, TX, USA
| |
Collapse
|
11
|
Portha B, Lacraz G, Chavey A, Figeac F, Fradet M, Tourrel-Cuzin C, Homo-Delarche F, Giroix MH, Bailbé D, Gangnerau MN, Movassat J. Islet structure and function in the GK rat. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 654:479-500. [PMID: 20217511 DOI: 10.1007/978-90-481-3271-3_21] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Type 2 diabetes mellitus (T2D) arises when the endocrine pancreas fails to secrete sufficient insulin to cope with the metabolic demand because of beta-cell secretory dysfunction and/or decreased beta-cell mass. Defining the nature of the pancreatic islet defects present in T2D has been difficult, in part because human islets are inaccessible for direct study. This review is aimed to illustrate to what extent the Goto-Kakizaki rat, one of the best characterized animal models of spontaneous T2D, has proved to be a valuable tool offering sufficient commonalities to study this aspect. A comprehensive compendium of the multiple functional GK islet abnormalities so far identified is proposed in this perspective. The pathogenesis of defective beta-cell number and function in the GK model is also discussed. It is proposed that the development of T2D in the GK model results from the complex interaction of multiple events: (i) several susceptibility loci containing genes responsible for some diabetic traits (distinct loci encoding impairment of beta-cell metabolism and insulin exocytosis, but no quantitative trait locus for decreased beta-cell mass); (ii) gestational metabolic impairment inducing an epigenetic programming of the offspring pancreas (decreased beta-cell neogenesis and proliferation) transmitted over generations; and (iii) loss of beta-cell differentiation related to chronic exposure to hyperglycaemia/hyperlipidaemia, islet inflammation, islet oxidative stress, islet fibrosis and perturbed islet vasculature.
Collapse
Affiliation(s)
- Bernard Portha
- Laboratoire B2PE, Unité BFA, Université Paris-Diderot et CNRS EAC4413, F - 75205 Paris Cedex13, France.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Pi J, Zhang Q, Fu J, Woods CG, Hou Y, Corkey BE, Collins S, Andersen ME. ROS signaling, oxidative stress and Nrf2 in pancreatic beta-cell function. Toxicol Appl Pharmacol 2009; 244:77-83. [PMID: 19501608 DOI: 10.1016/j.taap.2009.05.025] [Citation(s) in RCA: 248] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2009] [Revised: 05/22/2009] [Accepted: 05/27/2009] [Indexed: 12/16/2022]
Abstract
This review focuses on the emerging evidence that reactive oxygen species (ROS) derived from glucose metabolism, such as H(2)O(2), act as metabolic signaling molecules for glucose-stimulated insulin secretion (GSIS) in pancreatic beta-cells. Particular emphasis is placed on the potential inhibitory role of endogenous antioxidants, which rise in response to oxidative stress, in glucose-triggered ROS and GSIS. We propose that cellular adaptive response to oxidative stress challenge, such as nuclear factor E2-related factor 2 (Nrf2)-mediated antioxidant induction, plays paradoxical roles in pancreatic beta-cell function. On the one hand, induction of antioxidant enzymes protects beta-cells from oxidative damage and possible cell death, thus minimizing oxidative damage-related impairment of insulin secretion. On the other hand, the induction of antioxidant enzymes by Nrf2 activation blunts glucose-triggered ROS signaling, thus resulting in reduced GSIS. These two premises are potentially relevant to impairment of beta-cells occurring in the late and early stage of Type 2 diabetes, respectively. In addition, we summarized our recent findings that persistent oxidative stress due to absence of uncoupling protein 2 activates cellular adaptive response which is associated with impaired pancreatic beta-cell function.
Collapse
Affiliation(s)
- Jingbo Pi
- Division of Translational Biology, The Hamner Institutes for Health Sciences, 6 Davis Drive, Research Triangle Park, NC 27709, USA.
| | | | | | | | | | | | | | | |
Collapse
|
13
|
Impaired glucose-stimulated insulin secretion in the GK rat is associated with abnormalities in islet nitric oxide production. ACTA ACUST UNITED AC 2008; 151:139-46. [PMID: 18662725 DOI: 10.1016/j.regpep.2008.07.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2008] [Revised: 05/23/2008] [Accepted: 07/02/2008] [Indexed: 11/24/2022]
Abstract
We investigated implications of nitric oxide (NO) derived from islet neuronal constitutive NO synthase (ncNOS) and inducible NOS (iNOS) on insulin secretory mechanisms in the mildly diabetic GK rat. Islets from GK rats and Wistar controls were analysed for ncNOS and iNOS by HPLC, immunoblotting and immunocytochemistry in relation to insulin secretion stimulated by glucose or l-arginine in vitro and in vivo. No obvious difference in ncNOS fluorescence in GK vs control islets was seen but freshly isolated GK islets displayed a marked iNOS expression and activity. After incubation at low glucose GK islets showed an abnormal increase in both iNOS and ncNOS activities. At high glucose the impaired glucose-stimulated insulin release was associated with an increased iNOS expression and activity and NOS inhibition dose-dependently amplified insulin secretion in both GK and control islets. This effect by NOS inhibition was also evident in depolarized islets at low glucose, where forskolin had a further amplifying effect in GK but not in control islets. NOS inhibition increased basal insulin release in perfused GK pancreata and amplified insulin release after glucose stimulation in both GK and control pancreata, almost abrogating the nadir separating first and second phase in controls. A defective insulin response to l-arginine was seen in GK rats in vitro and in vivo, being partially restored by NOS inhibition. The results suggest that increased islet NOS activities might contribute to the defective insulin response to glucose and l-arginine in the GK rat. Excessive iNOS expression and activity might be deleterious for the beta-cells over time.
Collapse
|
14
|
Ostenson CG, Efendic S. Islet gene expression and function in type 2 diabetes; studies in the Goto-Kakizaki rat and humans. Diabetes Obes Metab 2007; 9 Suppl 2:180-6. [PMID: 17919192 DOI: 10.1111/j.1463-1326.2007.00787.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Defective beta-cell function with resulting impairment of glucose-stimulated insulin release is a critical factor in the pathogenesis of type 2 diabetes. Accumulated studies in pancreatic islets of the spontaneously diabetic Goto-Kakizaki (GK) rat suggest that this is a useful animal model of type 2 diabetes. The GK rat is non-obese, and abnormal glucose regulation develops early in life in association with impaired insulin secretion. There are some differences in islet morphology and function reported between different GK rat colonies. In addition to reduction of beta-cell mass, a number of beta-cell defects have been described with possible relevance for the reduced insulin secretion. Interestingly, some of these defects have also been shown in isolated islets from type 2 diabetic humans. The polygenic nature of diabetes heredity in the GK rat may well resemble the genetic basis in the majority of patients with type 2 diabetes. Here, we review studies concerning beta-cell function and islet gene expression in the GK rat and compare it with the limited number of investigations on similar topics in isolated islets from patients with type 2 diabetes.
Collapse
Affiliation(s)
- C-G Ostenson
- Department of Molecular Medicine and Surgery, Endocrine and Diabetes Unit, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden.
| | | |
Collapse
|
15
|
Noguchi H, Matsumoto S. Protein transduction technology offers a novel therapeutic approach for diabetes. ACTA ACUST UNITED AC 2007; 13:306-13. [PMID: 16858541 DOI: 10.1007/s00534-005-1038-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2005] [Accepted: 09/12/2005] [Indexed: 12/14/2022]
Abstract
Diabetes remains a major burden, with more than 200 million people affected worldwide, representing 6% of the population. New technology, known as protein transduction technology, has been recently developed. A variety of peptides, known as protein transduction domains or cell-penetrating peptides, have been characterized for their ability to translocate into live cells. There are numerous examples of biologically active full-length proteins and peptides that have been delivered to cells and tissues both in vitro and in vivo, suggesting new avenues for the treatment of several diseases. Some studies have shown that this technology is useful for the treatment of diabetes. In islet isolation and transplantation, cell-permeable peptides deliver anti-apoptotic molecules to protect islets. Another peptide provides immunosuppression for fully mismatched islet allografts in mice. These findings suggest that peptide drugs could lead to outcome improvement for pancreatic islet transplantation. In mice with type 2 diabetes, a cell-penetrating peptide markedly improves insulin resistance and ameliorates glucose tolerance. Moreover, the technology facilitates the differentiation of stem cells into insulin-producing cells. Protein transduction technology has opened up several possibilities for the development of new peptide/protein drugs for the treatment of diabetes.
Collapse
|
16
|
Hudecz F, Bánóczi Z, Csík G. Medium-sized peptides as built in carriers for biologically active compounds. Med Res Rev 2006; 25:679-736. [PMID: 15952174 DOI: 10.1002/med.20034] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A growing number of oligopeptides of natural and/or synthetic origin have been described and considered as targeting structures for delivery bioactive compounds into various cell types. This review will outline the discovery of peptide sequences and the corresponding mid-sized oligopeptides with membrane translocating properties and also summarize de novo designed structures possessing similar features. Conjugates and chimera constructs derived from these sequences with covalently attached bioactive peptide, epitope, oligonucleotide, PNA, drug, reporter molecule will be reviewed. A brief note will refer to the present understanding on the uptake mechanism at the end of each section.
Collapse
Affiliation(s)
- Ferenc Hudecz
- Research Group of Peptide Chemistry, Hungarian Academy of Sciences, Eötvös Loránd University, Budapest 112, POB 32, Hungary H-1518. hudecz@szerves,chem.elte.hu
| | | | | |
Collapse
|
17
|
Lajus S, Lang J. Splice variant 3, but not 2 of receptor protein-tyrosine phosphatase σ can mediate stimulation of insulin-secretion by α-latrotoxin. J Cell Biochem 2006; 98:1552-9. [PMID: 16552719 DOI: 10.1002/jcb.20871] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Alpha-latrotoxin (alpha-LTX) binds to several cell surface receptors including receptor protein-tyrosine phosphatase sigma (RPTPsigma). Here we demonstrate that transient overexpression of the short splice variant 3 conferred alpha-LTX induced secretion to hamster insulinoma (HIT-15) cells. In contrast, the long splice variant 2 containing four additional extracellular fibronectin-III domains was inactive in secretion or in a single cell assay. Toxin-sensitive (MIN6) and toxin-insensitive (HIT-T15) insulinoma cell lines as well as PC12 cells expressed similar amounts of endogenous short RPTPsigma splice variant suggesting that this receptor does not play a role for toxin-sensitivity.
Collapse
Affiliation(s)
- Sophie Lajus
- Institut Européen de Chimie et Biologie, JE 2390, F-33607 Bordeaux/Pessac, France
| | | |
Collapse
|
18
|
Lominadze G, Powell DW, Luerman GC, Link AJ, Ward RA, McLeish KR. Proteomic Analysis of Human Neutrophil Granules. Mol Cell Proteomics 2005; 4:1503-21. [PMID: 15985654 DOI: 10.1074/mcp.m500143-mcp200] [Citation(s) in RCA: 243] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Stimulated exocytosis of intracellular granules plays a critical role in conversion of inactive, circulating neutrophils to fully activated cells capable of chemotaxis, phagocytosis, and bacterial killing. The functional changes induced by exocytosis of each of the granule subsets, gelatinase (tertiary) granules, specific (secondary) granules, and azurophil (primary) granules, are poorly defined. To improve the understanding of the role of exocytosis of these granule subsets, a proteomic analysis of the azurophil, specific, and gelatinase granules from human neutrophils was performed. Two different methods for granule protein identification were applied. First, two-dimensional (2D) gel electrophoresis followed by MALDI-TOF MS analysis of peptides obtained by in-gel trypsin digestion of proteins was performed. Second, peptides from tryptic digests of granule membrane proteins were separated by two-dimensional microcapillary chromatography using strong cation exchange and reverse phase microcapillary high pressure liquid chromatography and analyzed with electrospray ionization tandem mass spectrometry (2D HLPC ESI-MS/MS). Our analysis identified 286 proteins on the three granule subsets, 87 of which were identified by MALDI MS and 247 were identified by 2D HPLC ESI-MS/MS. The increased sensitivity of 2D HPLC ESI-MS/MS, however, resulted in identification of over 500 proteins from subcellular organelles contaminating isolated granules. Defining the proteome of neutrophil granule subsets provides a basis for understanding the role of exocytosis in neutrophil biology. Additionally, the described methods may be applied to mobilizable compartments of other secretory cells.
Collapse
Affiliation(s)
- George Lominadze
- Department of Medicine, University of Louisville and the Veterans Affairs Medical Center, Louisville, Kentucky 40202, USA
| | | | | | | | | | | |
Collapse
|
19
|
Yang X, Li J, Zhou Y, Shen Q, Chen J, Li J. Discovery of novel inhibitor of human leukocyte common antigen-related phosphatase. Biochim Biophys Acta Gen Subj 2005; 1726:34-41. [PMID: 16198483 DOI: 10.1016/j.bbagen.2005.07.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2005] [Revised: 06/23/2005] [Accepted: 07/08/2005] [Indexed: 11/18/2022]
Abstract
Human leukocyte common antigen-related phosphatase (LAR) may play a role in type 2 diabetes and cancer, and in the development of the nervous system, and it may be an attractive target for the treatment of diabetes and cancer. We identified eight hits from the random screening of LAR D1 with a high-throughput screening assay. Further validation of the eight hits showed that the meD insertion was associated with inhibition of LAR D1D2 and LAR D1Q. These data suggest that the inserted meD peptide influences the interaction of the enzyme and inhibitor, which is consistent with the kinetic catalysis constants of the substrate pNPP. Our data showed that Hit 1, the first published novel inhibitor of LAR, is a competitive inhibitor with a K(i) of 330 nM that displays obvious selectivity for LAR and mouse PTPsigma, but not for other protein tyrosine phosphatases.
Collapse
Affiliation(s)
- Xiaoning Yang
- East China Normal University, Academy of Life Science, Shanghai 200062, P. R. China
| | | | | | | | | | | |
Collapse
|
20
|
Chen J, Ostenson CG. Inhibition of protein-tyrosine phosphatases stimulates insulin secretion in pancreatic islets of diabetic Goto-Kakizaki rats. Pancreas 2005; 30:314-7. [PMID: 15841039 DOI: 10.1097/01.mpa.0000161887.25115.6c] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
OBJECTIVES Because increased expression of protein tyrosine phosphatases in the pancreatic islets may contribute to impaired insulin secretion in diabetes, we studied the effects of the phosphatase inhibitor peroxovanadate (pV) in islets of spontaneously diabetic Goto-Kakizaki (GK) and control Wistar rats. METHODS Insulin release and glucose use were studied in isolated islets of GK and control rats. RESULTS Insulin release from isolated GK rat islets at 3.3 and 16.7 mmol/L glucose was enhanced by pV in a dose-dependent manner (0.1-1 mmol/L). This was partly in contrast to the effect of pV in Wistar rat islets, where insulin response to 16.7 mmol/L glucose was inhibited by 0.01-0.1 mmol/L of the compound. In GK rat islets, pV was a strong initiator of insulin release and also had some potentiating effect on glucose-stimulated insulin secretion, whereas in Wistar rat islets, pV only had an initiating, and lacked potentiating, effect. The PI3K inhibitor wortmannin suppressed pV-induced insulin release at 3.3 mmol/L but not at 16.7 mmol/L glucose in both GK and Wistar rat islets. The modulatory effects by pV on insulin release were not related to effects by the compound on islet glucose metabolism. CONCLUSIONS Our findings suggest that impaired insulin secretion in GK rat islets is accounted for, at least partly, by increased protein-tyrosine phosphatase activity in B cells.
Collapse
Affiliation(s)
- Jie Chen
- Department of Molecular Medicine, Endocrine and Diabetes Unit, Karolinska Hospital, Stockholm, Sweden
| | | |
Collapse
|
21
|
Mosén H, Salehi A, Alm P, Henningsson R, Jimenez-Feltström J, Ostenson CG, Efendic S, Lundquist I. Defective glucose-stimulated insulin release in the diabetic Goto-Kakizaki (GK) rat coincides with reduced activity of the islet carbon monoxide signaling pathway. Endocrinology 2005; 146:1553-8. [PMID: 15564331 DOI: 10.1210/en.2004-0851] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The Goto-Kakizaki (GK) rat displays a markedly reduced insulin response to glucose, a defect that is thought to be coupled to an impaired glucose signaling in the beta-cell. We have examined whether carbon monoxide (CO), derived from beta-cell heme oxygenase (HO), might be involved in the secretory dysfunction. Immunocytochemical labeling of constitutive HO (HO-2) showed no overt difference in fluorescence pattern in islets from GK vs. Wistar controls. However, isolated islets from GK rats displayed a markedly impaired HO activity measured as CO production (-50%), and immunoblotting revealed an approximately 50% reduction of HO-2 protein expression compared with Wistar controls. Furthermore, there was a prominent expression of inducible HO (HO-1) in GK islets. Incubation of isolated islets showed that the glucose-stimulated CO production and the glucose-stimulated insulin response were considerably reduced in GK islets compared with Wistar islets. Addition of the HO activator hemin or gaseous CO to the incubation media brought about a similar amplification of glucose-stimulated insulin release in GK and Wistar islets, suggesting that distal steps in the HO-CO signaling pathway were not appreciably affected. We conclude that the defective insulin response to glucose in the GK rat can be explained, at least in part, by a marked impairment of the glucose-HO-CO signaling pathway as manifested by a prominent decrease in glucose stimulation of islet CO production and a reduced expression of HO-2. A possible role of HO-1 expression as a compensatory mechanism in the GK islets is presently unclear.
Collapse
Affiliation(s)
- Henrik Mosén
- Department of Pharmacology, Institute of Physiological Sciences, University of Lund, BMC F13, S-221 84 Lund, Sweden.
| | | | | | | | | | | | | | | |
Collapse
|
22
|
Dietz GPH, Bähr M. Delivery of bioactive molecules into the cell: the Trojan horse approach. Mol Cell Neurosci 2005; 27:85-131. [PMID: 15485768 DOI: 10.1016/j.mcn.2004.03.005] [Citation(s) in RCA: 358] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2003] [Revised: 02/17/2004] [Accepted: 03/16/2004] [Indexed: 01/12/2023] Open
Abstract
In recent years, vast amounts of data on the mechanisms of neural de- and regeneration have accumulated. However, only in disproportionally few cases has this led to efficient therapies for human patients. Part of the problem is to deliver cell death-averting genes or gene products across the blood-brain barrier (BBB) and cellular membranes. The discovery of Antennapedia (Antp)-mediated transduction of heterologous proteins into cells in 1992 and other "Trojan horse peptides" raised hopes that often-frustrating attempts to deliver proteins would now be history. The demonstration that proteins fused to the Tat protein transduction domain (PTD) are capable of crossing the BBB may revolutionize molecular research and neurobiological therapy. However, it was only recently that PTD-mediated delivery of proteins with therapeutic potential has been achieved in models of neural degeneration in nerve trauma and ischemia. Several groups have published the first positive results using protein transduction domains for the delivery of therapeutic proteins in relevant animal models of human neurological disorders. Here, we give an extensive review of peptide-mediated protein transduction from its early beginnings to new advances, discuss their application, with particular focus on a critical evaluation of the limitations of the method, as well as alternative approaches. Besides applications in neurobiology, a large number of reports using PTD in other systems are included as well. Because each protein requires an individual purification scheme that yields sufficient quantities of soluble, transducible material, the neurobiologist will benefit from the experiences of other researchers in the growing field of protein transduction.
Collapse
|
23
|
Bernier M. Protein tyrosine phosphatases. Cell Biochem Biophys 2004. [DOI: 10.1385/cbb:40:3:209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
24
|
Huang J, Lin A, Narasimhan B, Quertermous T, Hsiung CA, Ho LT, Grove JS, Olivier M, Ranade K, Risch NJ, Olshen RA. Tree-structured supervised learning and the genetics of hypertension. Proc Natl Acad Sci U S A 2004; 101:10529-34. [PMID: 15249660 PMCID: PMC489971 DOI: 10.1073/pnas.0403794101] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
This paper is about an algorithm, FlexTree, for general supervised learning. It extends the binary tree-structured approach (Classification and Regression Trees, CART) although it differs greatly in its selection and combination of predictors. It is particularly applicable to assessing interactions: gene by gene and gene by environment as they bear on complex disease. One model for predisposition to complex disease involves many genes. Of them, most are pure noise; each of the values that is not the prevalent genotype for the minority of genes that contribute to the signal carries a "score." Scores add. Individuals with scores above an unknown threshold are predisposed to the disease. For the additive score problem and simulated data, FlexTree has cross-validated risk better than many cutting-edge technologies to which it was compared when small fractions of candidate genes carry the signal. For the model where only a precise list of aberrant genotypes is predisposing, there is not a systematic pattern of absolute superiority; however, overall, FlexTree seems better than the other technologies. We tried the algorithm on data from 563 Chinese women, 206 hypotensive, 357 hypertensive, with information on ethnicity, menopausal status, insulin-resistant status, and 21 loci. FlexTree and Logic Regression appear better than the others in terms of Bayes risk. However, the differences are not significant in the usual statistical sense.
Collapse
Affiliation(s)
- Jing Huang
- Affymetrix Inc., 3380 Central Expressway, Santa Clara, CA 95051, USA.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Kapp K, Metzinger E, Kellerer M, Häring HU, Lammers R. The protein tyrosine phosphatase alpha modifies insulin secretion in INS-1E cells. Biochem Biophys Res Commun 2004; 311:361-4. [PMID: 14592422 DOI: 10.1016/j.bbrc.2003.10.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Increasing evidence indicates a role of insulin signalling for insulin secretion from the pancreatic beta-cells. Therefore, regulators of insulin signalling, like protein tyrosine phosphatases, could also have an impact on insulin secretion. Here, we investigated a possible role of the negative regulator protein tyrosine phosphatase alpha (PTP alpha) for insulin secretion. RT-PCR analysis confirmed that both splice variants of the extracellular domain of PTP alpha that vary by an insert of 9 amino acids are expressed in human islets and insulinoma cells (INS-1E, RIN1046-38). Overexpression of the wild type PTP alpha splice variant containing the 9 amino acids reduced insulin secretion, as did a mutant form unable to bind Grb2 (Tyr798Phe). By contrast, overexpression of a phosphatase inactive mutant improved insulin secretion. These data reveal a functional relevance of PTP alpha for insulin secretion.
Collapse
Affiliation(s)
- Katja Kapp
- Medical Clinic IV, Otfried-Müller-Str. 10, 72076 Tuebingen, Germany
| | | | | | | | | |
Collapse
|
26
|
Protein tyrosine phosphatases. Cell Biochem Biophys 2004. [DOI: 10.1007/bf02739025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
27
|
Tomes CN, Roggero CM, De Blas G, Saling PM, Mayorga LS. Requirement of protein tyrosine kinase and phosphatase activities for human sperm exocytosis. Dev Biol 2004; 265:399-415. [PMID: 14732401 DOI: 10.1016/j.ydbio.2003.09.032] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The acrosome is a membrane-limited granule that overlies the nucleus of the mature spermatozoon. In response to physiological or pharmacological stimuli, sperm undergo calcium-dependent exocytosis termed the acrosome reaction, which is an absolute prerequisite for fertilization. Protein tyrosine phosphorylation and dephosphorylation are a mechanisms by which multiple cellular events are regulated. Here we report that calcium induces tyrosine phosphorylation in streptolysin O (SLO)-permeabilized human sperm. As expected, pretreatment with tyrphostin A47-a tyrosine kinase inhibitor-abolishes the calcium effect. Interestingly, the calcium-induced increase in tyrosine phosphorylation has a functional correlate in sperm exocytosis. Masking of phosphotyrosyl groups with a specific antibody or inhibition of tyrosine kinases with genistein, tyrphostin A47, and tyrphostin A51 prevent the acrosome reaction. By reversibly sequestering intra-acrosomal calcium with a photo-inhibitable chelator, we show a requirement for protein tyrosine phosphorylation late in the exocytotic pathway, after the efflux of intra-acrosomal calcium. Both mouse and human sperm contain highly active tyrosine phosphatases. Importantly, this activity declines when sperm are incubated under capacitating conditions. Inhibition of tyrosine phosphatases with pervanadate, bis(N,N-dimethylhydroxoamido)hydroxovanadate, ethyl-3,4-dephostatin, and phenylarsine oxide prevents the acrosome reaction. Our results show that both tyrosine kinases and phosphatases play a central role in sperm exocytosis.
Collapse
Affiliation(s)
- C N Tomes
- Laboratorio de Biología Celular y Molecular, Instituto de Histología y Embriología (IHEM-CONICET), Facultad de Ciencias Médicas, CC56, Universidad Nacional de Cuyo, 5500 Mendoza, Argentina.
| | | | | | | | | |
Collapse
|
28
|
Abstract
Changes in protein tyrosine phosphorylation are an essential aspect of egg activation after fertilization. Such changes result from the net contributions of both tyrosine kinases and phosphatases (PTP). This study was conducted to determine what role(s) PTP may have in egg activation. We identified four novel PTP in Chaetopterus pergamentaceus oocytes, cpPTPNT6, cpPTPNT7, cpPTPR2B, and cpPTPR2A, that have significant homology to, respectively, human PTPsigma, -rho, -D2 and -BAS. The first two are cytosolic and the latter two are transmembrane. Several PTP inhibitors were tested to see if they would affect Chaetopterus pergamentaceus fertilization. Eggs treated with beta-bromo-4-hydroxyacetophenone (PTP inhibitor 1) exhibited microvillar elongation, which is a sign of cortical changes resulting from activation. Those treated with Na3VO4 underwent full parthenogenetic activation, including polar body formation and pseudocleavage and did so independently of extracellular Ca2+, which is required for the Ca2+ oscillations that initiate development after fertilization. Fluorescence microscopy identified phosphotyrosine-containing proteins in the cortex and around the nucleus of vanadate-activated eggs, whereas in fertilized eggs they were concentrated only in the cortex. Immunoblots of vanadate-activated and fertilized eggs showed tyrosine hyperphosphorylation of approximately 140 kDa protein. These results suggest that PTP most likely maintain the egg in an inactive state by dephosphorylation of proteins independent of the Ca2+ oscillations in the activation process.
Collapse
Affiliation(s)
- Shantá D Hinton
- Department of Biology, Howard University, Washington, DC 20059, USA
| | | | | |
Collapse
|
29
|
Sim ATR, Baldwin ML, Rostas JAP, Holst J, Ludowyke RI. The role of serine/threonine protein phosphatases in exocytosis. Biochem J 2003; 373:641-59. [PMID: 12749763 PMCID: PMC1223558 DOI: 10.1042/bj20030484] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2003] [Revised: 05/09/2003] [Accepted: 05/16/2003] [Indexed: 10/27/2022]
Abstract
Modulation of exocytosis is integral to the regulation of cellular signalling, and a variety of disorders (such as epilepsy, hypertension, diabetes and asthma) are closely associated with pathological modulation of exocytosis. Emerging evidence points to protein phosphatases as key regulators of exocytosis in many cells and, therefore, as potential targets for the design of novel therapies to treat these diseases. Diverse yet exquisite regulatory mechanisms have evolved to direct the specificity of these enzymes in controlling particular cell processes, and functionally driven studies have demonstrated differential regulation of exocytosis by individual protein phosphatases. This Review discusses the evidence for the regulation of exocytosis by protein phosphatases in three major secretory systems, (1) mast cells, in which the regulation of exocytosis of inflammatory mediators plays a major role in the respiratory response to antigens, (2) insulin-secreting cells in which regulation of exocytosis is essential for metabolic control, and (3) neurons, in which regulation of exocytosis is perhaps the most complex and is essential for effective neurotransmission.
Collapse
Affiliation(s)
- Alistair T R Sim
- School of Biomedical Sciences, Faculty of Health, University of Newcastle, and Clinical Neuroscience Program, Hunter Medical Research Institute, Callaghan, NSW 2308, Australia.
| | | | | | | | | |
Collapse
|