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Song X, Jiao X, Yan H, Yu L, Jiang L, Zhang M, Chen L, Ju M, Wang L, Wei Q, Zhao L, Wei M. Overexpression of PTPRN Promotes Metastasis of Lung Adenocarcinoma and Suppresses NK Cell Cytotoxicity. Front Cell Dev Biol 2021; 9:622018. [PMID: 34150744 PMCID: PMC8207963 DOI: 10.3389/fcell.2021.622018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 04/06/2021] [Indexed: 01/04/2023] Open
Abstract
Background Lung adenocarcinoma (LUAD) is the most common diagnostic histologic subtype of non-small cell lung cancer, but the role of receptor-type tyrosine-protein phosphatase-like N (PTPRN) in LUAD has not been studied. Methods We conducted a bioinformatic analysis to identify the expression of PTPRN on LUAD data from the Cancer Genome Atlas (TCGA) and the relationship between PTPRN and overall survival of LUAD patients. The effects of PTPRN on the migration ability of LUAD cells and the underlying mechanisms were investigated by in vitro and in vivo assays (i.e., wound healing assay, transwell assay, western blotting, xenograft model, and immunohistochemistry). Gene-set enrichment analysis and computational resource were used to analyze the correlation between PTPRN and different tumor-infiltrating immune cells (TIICs). Lactate dehydrogenase assay and Enzyme-linked immunosorbent assay were conducted to examine natural killer (NK) cell cytotoxicity. Results In our study, we found that PTPRN was up-regulated in LUAD and related to metastasis of LUAD patients. Besides, PTPRN was correlated with poor prognosis in the TCGA-LUAD dataset. PTPRN overexpression promoted LUAD cell migration and the expression of EMT markers by influencing MEK/ERK and PI3K/AKT signaling. Moreover, PTPRN expression was significantly associated with TIICs, especially NK cells. A549 and H1299 cells overexpressed PTPRN inhibited NK cell cytotoxicity. Conclusion Taken together, these findings demonstrated that PTPRN might be a potential and novel therapeutic target modulating antitumor immune response in treatment of LUAD.
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Affiliation(s)
- Xinyue Song
- Department of Pharmacology, School of Pharmacy, China Medical University, Shenyang, China.,Liaoning Key Laboratory of Molecular Targeted Anti-Tumor Drug Development and Evaluation, China Medical University, Shenyang, China.,Liaoning Cancer Immune Peptide Drug Engineering Technology Research Center, China Medical University, Shenyang, China.,Key Laboratory of Precision Diagnosis and Treatment of Gastrointestinal Tumors, Ministry of Education, China Medical University, Shenyang, China
| | - Xue Jiao
- Department of Pharmacology, School of Pharmacy, China Medical University, Shenyang, China.,Liaoning Key Laboratory of Molecular Targeted Anti-Tumor Drug Development and Evaluation, China Medical University, Shenyang, China.,Liaoning Cancer Immune Peptide Drug Engineering Technology Research Center, China Medical University, Shenyang, China.,Key Laboratory of Precision Diagnosis and Treatment of Gastrointestinal Tumors, Ministry of Education, China Medical University, Shenyang, China
| | - Han Yan
- Department of Pharmacology, School of Pharmacy, China Medical University, Shenyang, China.,Liaoning Key Laboratory of Molecular Targeted Anti-Tumor Drug Development and Evaluation, China Medical University, Shenyang, China.,Liaoning Cancer Immune Peptide Drug Engineering Technology Research Center, China Medical University, Shenyang, China.,Key Laboratory of Precision Diagnosis and Treatment of Gastrointestinal Tumors, Ministry of Education, China Medical University, Shenyang, China
| | - Lifeng Yu
- Department of Pharmacology, School of Pharmacy, China Medical University, Shenyang, China.,Liaoning Key Laboratory of Molecular Targeted Anti-Tumor Drug Development and Evaluation, China Medical University, Shenyang, China.,Liaoning Cancer Immune Peptide Drug Engineering Technology Research Center, China Medical University, Shenyang, China.,Key Laboratory of Precision Diagnosis and Treatment of Gastrointestinal Tumors, Ministry of Education, China Medical University, Shenyang, China
| | - Longyang Jiang
- Department of Pharmacology, School of Pharmacy, China Medical University, Shenyang, China.,Liaoning Key Laboratory of Molecular Targeted Anti-Tumor Drug Development and Evaluation, China Medical University, Shenyang, China.,Liaoning Cancer Immune Peptide Drug Engineering Technology Research Center, China Medical University, Shenyang, China.,Key Laboratory of Precision Diagnosis and Treatment of Gastrointestinal Tumors, Ministry of Education, China Medical University, Shenyang, China
| | - Ming Zhang
- Department of Pharmacology, School of Pharmacy, China Medical University, Shenyang, China.,Liaoning Key Laboratory of Molecular Targeted Anti-Tumor Drug Development and Evaluation, China Medical University, Shenyang, China.,Liaoning Cancer Immune Peptide Drug Engineering Technology Research Center, China Medical University, Shenyang, China.,Key Laboratory of Precision Diagnosis and Treatment of Gastrointestinal Tumors, Ministry of Education, China Medical University, Shenyang, China
| | - Lianze Chen
- Department of Pharmacology, School of Pharmacy, China Medical University, Shenyang, China.,Liaoning Key Laboratory of Molecular Targeted Anti-Tumor Drug Development and Evaluation, China Medical University, Shenyang, China.,Liaoning Cancer Immune Peptide Drug Engineering Technology Research Center, China Medical University, Shenyang, China.,Key Laboratory of Precision Diagnosis and Treatment of Gastrointestinal Tumors, Ministry of Education, China Medical University, Shenyang, China
| | - Mingyi Ju
- Department of Pharmacology, School of Pharmacy, China Medical University, Shenyang, China.,Liaoning Key Laboratory of Molecular Targeted Anti-Tumor Drug Development and Evaluation, China Medical University, Shenyang, China.,Liaoning Cancer Immune Peptide Drug Engineering Technology Research Center, China Medical University, Shenyang, China.,Key Laboratory of Precision Diagnosis and Treatment of Gastrointestinal Tumors, Ministry of Education, China Medical University, Shenyang, China
| | - Lin Wang
- Department of Pharmacology, School of Pharmacy, China Medical University, Shenyang, China.,Liaoning Key Laboratory of Molecular Targeted Anti-Tumor Drug Development and Evaluation, China Medical University, Shenyang, China.,Liaoning Cancer Immune Peptide Drug Engineering Technology Research Center, China Medical University, Shenyang, China.,Key Laboratory of Precision Diagnosis and Treatment of Gastrointestinal Tumors, Ministry of Education, China Medical University, Shenyang, China
| | - Qian Wei
- Department of Pharmacology, School of Pharmacy, China Medical University, Shenyang, China.,Liaoning Key Laboratory of Molecular Targeted Anti-Tumor Drug Development and Evaluation, China Medical University, Shenyang, China.,Liaoning Cancer Immune Peptide Drug Engineering Technology Research Center, China Medical University, Shenyang, China.,Key Laboratory of Precision Diagnosis and Treatment of Gastrointestinal Tumors, Ministry of Education, China Medical University, Shenyang, China
| | - Lin Zhao
- Department of Pharmacology, School of Pharmacy, China Medical University, Shenyang, China.,Liaoning Key Laboratory of Molecular Targeted Anti-Tumor Drug Development and Evaluation, China Medical University, Shenyang, China.,Liaoning Cancer Immune Peptide Drug Engineering Technology Research Center, China Medical University, Shenyang, China.,Key Laboratory of Precision Diagnosis and Treatment of Gastrointestinal Tumors, Ministry of Education, China Medical University, Shenyang, China
| | - Minjie Wei
- Department of Pharmacology, School of Pharmacy, China Medical University, Shenyang, China.,Shenyang Kangwei Medical Laboratory Analysis Co. LTD., Shenyang, China
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2
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Liu F, Horton-Sparks K, Hull V, Li RW, Martínez-Cerdeño V. The valproic acid rat model of autism presents with gut bacterial dysbiosis similar to that in human autism. Mol Autism 2018; 9:61. [PMID: 30555669 PMCID: PMC6288876 DOI: 10.1186/s13229-018-0251-3] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 11/26/2018] [Indexed: 02/07/2023] Open
Abstract
Background Gut microbiota has the capacity to impact the regular function of the brain, which can in turn affect the composition of microbiota. Autism spectrum disorder (ASD) patients suffer from gastrointestinal problems and experience changes in gut microbiota; however, it is not yet clear whether the change in the microbiota associated with ASD is a cause or a consequence of the disease. Methods We have investigated the species richness and microbial composition in a valproic acid (VPA)-induced rat model autism. Fecal samples from the rectum were collected at necropsy, microbial total DNA was extracted, 16 rRNA genes sequenced using Illumina, and the global microbial co-occurrence network was constructed using a random matrix theory-based pipeline. Collected rat microbiome data were compared to available data derived from cases of autism. Results We found that VPA administration during pregnancy reduced fecal microbial richness, changed the gut microbial composition, and altered the metabolite potential of the fecal microbial community in a pattern similar to that seen in patients with ASD. However, the global network property and network composition as well as microbial co-occurrence patterns were largely preserved in the offspring of rats exposed to prenatal administration of VPA. Conclusions Our data on the microbiota of the VPA rat model of autism indicate that this model, in addition to behaviorally and anatomically mimicking the autistic brain as previously shown, also mimics the microbiome features of autism, making it one of the best-suited rodent models for the study of autism and ASD.
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Affiliation(s)
- Fang Liu
- College of Food Science and Engineering, Ocean University of China, Qingdao, China
| | - Kayla Horton-Sparks
- Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children Northern California, 2504 Stockton Blvd, Sacramento, CA 95817 USA
| | - Vanessa Hull
- Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children Northern California, 2504 Stockton Blvd, Sacramento, CA 95817 USA
| | - Robert W. Li
- United States Department of Agriculture, Agriculture Research Service (USDA-ARS), Animal Genomics and Improvement Laboratory, Beltsville, MD USA
| | - Verónica Martínez-Cerdeño
- Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children Northern California, 2504 Stockton Blvd, Sacramento, CA 95817 USA
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, Sacramento, CA USA
- MIND Institute, Sacramento, CA USA
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3
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Biochemical, biophysical, and functional properties of ICA512/IA-2 RESP18 homology domain. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2016; 1864:511-22. [DOI: 10.1016/j.bbapap.2016.01.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 01/04/2016] [Accepted: 01/29/2016] [Indexed: 02/04/2023]
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4
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X-ray structure of the mature ectodomain of phogrin. ACTA ACUST UNITED AC 2014; 16:1-9. [PMID: 25421040 DOI: 10.1007/s10969-014-9191-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 11/19/2014] [Indexed: 10/24/2022]
Abstract
Phogrin/IA-2β and ICA512/IA-2 are two paralogs receptor-type protein-tyrosine phosphatases (RPTP) that localize in secretory granules of various neuroendocrine cells. In pancreatic islet β-cells, they participate in the regulation of insulin secretion, ensuring proper granulogenesis, and β-cell proliferation. The role of their cytoplasmic tail has been partially unveiled, while that of their luminal region remains unclear. To advance the understanding of its structure-function relationship, the X-ray structure of the mature ectodomain of phogrin (ME phogrin) at pH 7.4 and 4.6 has been solved at 1.95- and 2.01-Å resolution, respectively. Similarly to the ME of ICA512, ME phogrin adopts a ferredoxin-like fold: a sheet of four antiparallel β-strands packed against two α-helices. Sequence conservation among vertebrates, plants and insects suggests that the structural similarity extends to all the receptor family. Crystallized ME phogrin is monomeric, in agreement with solution studies but in striking contrast with the behavior of homodimeric ME ICA512. The structural details that may cause the quaternary structure differences are analyzed. The results provide a basis for building models of the overall orientation and oligomerization state of the receptor in biological membranes.
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Gesche J, Fehrenbach H, Koslowski R, Ohler FM, Pynn CJ, Griese M, Poets CF, Bernhard W. rhKGF stimulates lung surfactant production in neonatal rats in vivo. Pediatr Pulmonol 2011; 46:882-95. [PMID: 21462359 DOI: 10.1002/ppul.21443] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Revised: 02/07/2011] [Accepted: 02/09/2011] [Indexed: 01/03/2023]
Abstract
Surfactant deficiency and bronchopulmonary dysplasia (BPD), major obstacles in preterm infants, are addressed with pre- and postnatal glucocorticoids which also evoke harmful catabolic side-effects. Keratinocyte growth factor (KGF) accelerates surfactant production in fetal type II pneumocytes (PN-II), protects epithelia from injury and is deficient in lungs developing BPD, highlighting its potential efficacy in neonates. Neonatal rats were treated with recombinant human (rh)KGF, betamethasone, or their combination for 48 hr prior to sacrifice after which body weight, surfactant, and tissue phosphatidylcholines (PC) were investigated at postnatal d3, d7, d15, and d21. Pneumocyte proliferation, surfactant protein (SP) expression and SP-B/C in lung lavage fluid (LLF) were also determined at d7 and d21 to identify broader surfactant changes occurring at the beginning and end of the initial alveolarization phase. While all treatments increased secreted surfactant PC, BM compromised animal growth whereas rhKGF did not. At d3 rhKGF was more effective in male compared to female rats. Single treatments became less effective towards d21. Neither treatment altered PC composition in LLF. BM inhibited PN-II proliferation and increased surfactant PCs at the expense of tissue PCs. rhKGF however increased surfactant PCs without decreasing other PC species. Whereas SP-B/C gene expression was induced by all treatments, the changes in secreted SP-B/C mirrored those observed for surfactant PC. Our results encourage investigation of the mechanisms by which rhKGF improves surfactant homoeostasis, and detailed examination of its efficacy in neonatal lung injury models with a view to implementing it as a non-catabolic surfactant-increasing therapeutic in neonatal intensive care.
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Affiliation(s)
- Jens Gesche
- Faculty of Medicine, Department of Neonatology, Eberhard-Karls-University, Tübingen, Germany
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6
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Nath M, Offers M, Hummel M, Seissler J. Isolation and in vitro expansion of Lgr6-positive multipotent hair follicle stem cells. Cell Tissue Res 2011; 344:435-44. [PMID: 21484413 DOI: 10.1007/s00441-011-1165-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Accepted: 03/09/2011] [Indexed: 12/13/2022]
Abstract
Hair follicles (HFs) are a well-known niche of multipotent stem cells. Recently, HF cells expressing leucine-rich orphan G protein-coupled receptors (Lgr) have been described as multipotent adult stem cells with a high potential for regenerative therapies. We have now established the conditions for the isolation and long-term expansion of stem cells from HFs (HFSCs) and analyzed their characteristics (reverse transcription with the polymerase chain reaction, immunohistochemistry) and multipotent capacity (differentiation assays). HFSCs possess a high self-renewal capacity and share characteristics of putative HF epithelial stem cells, such as the expression of Lgr6, cytokeratins (Ck18, Ck19), and multipotent stem cell markers (Sca-1, Bcrp1, nestin, P75NTR). Under defined cell culture conditions, HFSCs are able to differentiate into mesenchymal lineages (adipocytes, chondrocytes, muscle cells) or neurons (βIII-tubulin). We report, for the first time, an in vitro culture method to isolate Lgr6-positive stem cells from HFs. HFSCs represent a unique tool for studying the cell characteristics of Lgr6-positive cells and should provide a novel easily accessible source for regenerative therapies.
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Affiliation(s)
- Miriam Nath
- Diabetes Center, Medical Clinic Innenstadt, Ludwig Maximilian's University Munich, Ziemssenstraße 1, 80336, Munich, Germany
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7
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Torii S, Saito N, Kawano A, Hou N, Ueki K, Kulkarni RN, Takeuchi T. Gene silencing of phogrin unveils its essential role in glucose-responsive pancreatic beta-cell growth. Diabetes 2009; 58:682-92. [PMID: 19073770 PMCID: PMC2646067 DOI: 10.2337/db08-0970] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Phogrin and IA-2, autoantigens in insulin-dependent diabetes, have been shown to be involved in insulin secretion in pancreatic beta-cells; however, implications at a molecular level are confusing from experiment to experiment. We analyzed biological functions of phogrin in beta-cells by an RNA interference technique. RESEARCH DESIGN AND METHODS Adenovirus-mediated expression of short hairpin RNA specific for phogrin (shPhogrin) was conducted using cultured beta-cell lines and mouse islets. Both glucose-stimulated insulin secretion and cell proliferation rate were determined in the phogrin-knockdown cells. Furthermore, protein expression was profiled in these cells. To see the binding partner of phogrin in beta-cells, coimmunoprecipitation analysis was carried out. RESULTS Adenoviral expression of shPhogrin efficiently decreased its endogenous expression in pancreatic beta-cells. Silencing of phogrin in beta-cells abrogated the glucose-mediated mitogenic effect, which was accompanied by a reduction in the level of insulin receptor substrate 2 (IRS2) protein, without any changes in insulin secretion. Phogrin formed a complex with insulin receptor at the plasma membrane, and their interaction was promoted by high-glucose stimulation that in turn led to stabilization of IRS2 protein. Corroboratively, phogrin knockdown had no additional effect on the proliferation of beta-cell line derived from the insulin receptor-knockout mouse. CONCLUSIONS Phogrin is involved in beta-cell growth via regulating stability of IRS2 protein by the molecular interaction with insulin receptor. We propose that phogrin and IA-2 function as an essential regulator of autocrine insulin action in pancreatic beta-cells.
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Affiliation(s)
- Seiji Torii
- Secretion Biology Lab, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, Japan
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8
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Torii S. Expression and function of IA-2 family proteins, unique neuroendocrine-specific protein-tyrosine phosphatases. Endocr J 2009; 56:639-48. [PMID: 19550073 DOI: 10.1507/endocrj.k09e-157] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
IA-2 (also known as islet cell antigen ICA-512) and IA-2 beta (also known as phogrin, phosphatase homologue in granules of insulinoma) are major autoantigens in insulin-dependent diabetes mellitus (IDDM). Autoantibodies against both proteins are expressed years before clinical onset, and they become predictive markers for high-risk subjects. However, the role of these genes in the IDDM pathogenesis has been reported fairly negative by recent studies. IA-2 and IA-2 beta are type I transmembrane proteins that possess one inactive protein-tyrosine phosphatase (PTP) domain in the cytoplasmic region, and act as one of the constituents of regulated secretory pathways in various neuroendocrine cell types including pancreatic beta-cells. Existence of IA-2 homologues in different species suggests a fundamental role in neuroendocrine function. Studies of knockout animals have shown their involvement in maintaining hormone content, however, their specific steps in the secretory pathway IA-2 functions as well as their molecular mechanisms in the hormone content regulation are still unknown. More recent studies have suggested a novel function showing that they contribute to pancreatic beta-cell growth. This review attempts to show the possible biological functions of IA-2 family, focusing on their expression and localization in the neuroendocrine cells.
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Affiliation(s)
- Seiji Torii
- Department of Molecular Medicine, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan.
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Nitescu N, Grimberg E, Ricksten SE, Marcussen N, Nordlinder H, Guron G. Effects of thrombin inhibition with melagatran on renal hemodynamics and function and liver integrity during early endotoxemia. Am J Physiol Regul Integr Comp Physiol 2006; 292:R1117-24. [PMID: 17068159 DOI: 10.1152/ajpregu.00471.2006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sepsis is associated with an activation of the coagulation system and multiorgan failure. The aim of the study was to examine the effects of selective thrombin inhibition with melagatran on renal hemodynamics and function, and liver integrity, during early endotoxemia. Endotoxemia was induced in thiobutabarbital-anesthetized rats by an intravenous bolus dose of lipopolysaccharide (LPS; 6 mg/kg). Sham-Saline, LPS-Saline, and LPS-Melagatran study groups received isotonic saline or melagatran immediately before (0.75 micromol/kg iv) and continuously during (0.75 micromol.kg(-1).h(-1) iv) 4.5 h of endotoxemia. Kidney function, renal blood flow (RBF), and intrarenal cortical and outer medullary perfusion (OMLDF) measured by laser-Doppler flowmetry were analyzed throughout. Markers of liver injury and tumor necrosis factor (TNF)-alpha were measured in plasma after 4.5 h of endotoxemia. In addition, liver histology and gene expression were examined. Melagatran treatment prevented the decline in OMLDF observed in the LPS-Saline group (P < 0.05, LPS-Melagatran vs. LPS-Saline). However, melagatran did not ameliorate reductions in mean arterial pressure, RBF, renal cortical perfusion, and glomerular filtration rate or attenuate tubular dysfunctions during endotoxemia. Melagatran reduced the elevated plasma concentrations of aspartate aminotransferase (-34 +/- 11%, P < 0.05), alanine aminotransferase (-21 +/- 7%, P < 0.05), bilirubin (-44 +/- 9%, P < 0.05), and TNF-alpha (-32 +/- 14%, P < 0.05) in endotoxemia. Melagatran did not diminish histological abnormalities in the liver or the elevated hepatic gene expression of TNF-alpha, intercellular adhesion molecule-1, and inducible nitric oxide synthase in endotoxemic rats. In summary, thrombin inhibition with melagatran preserved renal OMLDF, attenuated liver dysfunction, and reduced plasma TNF-alpha levels during early endotoxemia.
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Affiliation(s)
- Nicoletta Nitescu
- Department of Anesthesiology and Intensive Care, Institute of Clinical Sciences, Sahlgrenska University Hospital, S-413 45 Göteborg, Sweden.
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10
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Knoch KP, Meisterfeld R, Kersting S, Bergert H, Altkrüger A, Wegbrod C, Jäger M, Saeger HD, Solimena M. cAMP-dependent phosphorylation of PTB1 promotes the expression of insulin secretory granule proteins in beta cells. Cell Metab 2006; 3:123-34. [PMID: 16459313 DOI: 10.1016/j.cmet.2005.12.008] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2005] [Revised: 11/13/2005] [Accepted: 12/29/2005] [Indexed: 11/23/2022]
Abstract
Glucose stimulates the exocytosis of insulin secretory granules of pancreatic beta cells. Granule stores are quickly refilled by activation of posttranscriptional mechanisms that enhance the biosynthesis of granule components. Rapid replacement of granules is important to sustain insulin secretion, since new granules appear to be preferentially released. Posttranscriptional regulation of granule biogenesis includes the glucose-induced nucleocytoplasmic translocation of polypyrimidine tract binding protein 1 (PTB1), which binds mRNAs encoding granule proteins, and thus promotes their stabilization and translation. Glucagon-like peptide 1 (GLP-1) potentiates glucose-stimulated insulin gene expression and secretion by increasing cAMP levels in beta cells. Here, we show that elevation of cAMP levels causes the protein kinase A-dependent phosphorylation and nucleocytoplasmic translocation of PTB1, thereby preventing the rapid degradation of insulin mRNA and enhancing the expression of various granule proteins. Taken together, these findings identify PTB1 as a common downstream target of glucose and GLP-1 for the posttranscriptional upregulation of granule biogenesis.
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Affiliation(s)
- Klaus-Peter Knoch
- Laboratory of Experimental Diabetology, Medical School, Dresden University of Technology, Fetscherstrasse 74, 01307 Dresden, Germany
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Bergert H, Knoch KP, Meisterfeld R, Jäger M, Ouwendijk J, Kersting S, Saeger HD, Solimena M. Effect of oxygenated perfluorocarbons on isolated rat pancreatic islets in culture. Cell Transplant 2005; 14:441-8. [PMID: 16285252 DOI: 10.3727/000000005783982873] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
One impediment for a wider application of islet transplantation is the limited number of donor pancreata for islet isolation. A more efficient utilization of available organs could in part alleviate this problem. Perfluorocarbons (PFCs) have a high oxygen solubility coefficient and maintain high oxygen partial pressures for extended time. They serve also as oxygen "reservoirs" for harvested organs in pancreas organ transplantation. The aim of this study was to test whether the use of PFCs could also be beneficial for the secretory activity and overall viability of cultured purified islets before transplantation. Purified rat islets were cultured in static conditions with or without oxygen-saturated PFCs for 1 or 7 days. Cell death and apoptosis were assessed by trypan blue staining, DNA strand breaks, and caspase 3/7 activity. mRNA levels of insulin and ICA512/IA-2, a membrane marker of secretory granules (SGs), were quantitated by real-time PCR, whereas insulin content and secretion were measured by RIA. Polypyrimidine tract binding protein (PTB), which promotes SG biogenesis, was assessed by Western blotting. The number of SGs and the ultrastructural appearance of beta5-cells were analyzed by cryoimmunoelectronmicroscopy for insulin. Various parameters, including caspase activity, insulin and ICA512/IA-2 mRNA levels, PTB expression, number of secretory granules, and ultrastructural appearance did not significantly differ between control and PFC-cultured islets. On the other hand, PFC culture islets showed significantly increased DNA fragmentation and a reduced insulin stimulation index at both time points compared to control islets. While advantageous for the transport of human harvested organs, the use of PFH in the culture may be comparable to and/or not provide advantage over conventional protocols for culture of islets for transplantation.
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Affiliation(s)
- Hendrik Bergert
- Department of Experimental Diabetology, School of Medicine, University of Technology Dresden, Germany.
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12
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Xu W, Gao Z, Wu J, Wolf BA. Interferon-gamma-induced regulation of the pancreatic derived cytokine FAM3B in islets and insulin-secreting betaTC3 cells. Mol Cell Endocrinol 2005; 240:74-81. [PMID: 16006032 DOI: 10.1016/j.mce.2005.05.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2005] [Revised: 05/19/2005] [Accepted: 05/20/2005] [Indexed: 10/25/2022]
Abstract
The pancreatic-derived factor (PANDER, FAM3B) is a novel protein that is beta-cell specific and induces beta-cell death. PANDER is localized to insulin-containing granules-based on confocal microscopy and immunogold electron microscopy. PANDER protein was detected in the conditioned medium of betaTC3 cells. Using real-time reverse transcription-polymerase chain reaction, treatment of betaTC3 cells with IL-1beta + TNFalpha + IFNgamma induced a significant seven-fold increase in PANDER mRNA expression (n = 3; p < 0.01 at 24 h, p < 0.05 at 48 h), while IFNgamma alone caused a 3.2-fold increase (n = 3; p < 0.01 at 24 h) compared to unstimulated and time-matched vehicle controls. IL-1beta or TNFalpha alone had no effect. Under those conditions, a similar up-regulation was also observed in mouse islet cells, with increases in PANDER mRNA of 5.9-fold and 5.0-fold after treatment with IL-1beta + TNFalpha + IFNgamma or IFNgamma alone. Because PANDER mRNA expression is up-regulated by IFNgamma, a cytokine implicated in the pathogenesis of type 1 diabetes, PANDER may contribute to the pathogenesis of beta-cell death.
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Affiliation(s)
- Weizhen Xu
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, 19104, USA
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Trajkovski M, Mziaut H, Altkrüger A, Ouwendijk J, Knoch KP, Müller S, Solimena M. Nuclear translocation of an ICA512 cytosolic fragment couples granule exocytosis and insulin expression in {beta}-cells. ACTA ACUST UNITED AC 2004; 167:1063-74. [PMID: 15596545 PMCID: PMC2172607 DOI: 10.1083/jcb.200408172] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Islet cell autoantigen 512 (ICA512)/IA-2 is a receptor tyrosine phosphatase-like protein associated with the insulin secretory granules (SGs) of pancreatic β-cells. Here, we show that exocytosis of SGs and insertion of ICA512 in the plasma membrane promotes the Ca2+-dependent cleavage of ICA512 cytoplasmic domain by μ-calpain. This cleavage occurs at the plasma membrane and generates an ICA512 cytosolic fragment that is targeted to the nucleus, where it binds the E3-SUMO ligase protein inhibitor of activated signal transducer and activator of transcription-y (PIASy) and up-regulates insulin expression. Accordingly, this novel pathway directly links regulated exocytosis of SGs and control of gene expression in β-cells, whose impaired insulin production and secretion causes diabetes.
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Affiliation(s)
- Mirko Trajkovski
- Experimental Diabetology, Carl Gustav Carus Medical School, Dresden University of Technology, Dresden, Germany
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Mendez II, Chung YH, Jun HS, Yoon JW. Immunoregulatory role of nitric oxide in Kilham rat virus-induced autoimmune diabetes in DR-BB rats. THE JOURNAL OF IMMUNOLOGY 2004; 173:1327-35. [PMID: 15240727 DOI: 10.4049/jimmunol.173.2.1327] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Macrophages play a critical role in the pathogenesis of Kilham rat virus (KRV)-induced autoimmune diabetes in diabetes-resistant BioBreeding (DR-BB) rats. This investigation was initiated to determine the role of macrophage-derived soluble mediators, particularly NO, in the pathogenesis of KRV-induced diabetes in DR-BB rats. We found that the expression of inducible NO synthase (iNOS), an enzyme responsible for NO production, was significantly increased during the early phase of KRV infection. Inhibition of iNOS by aminoguanidine (AG) treatment resulted in the prevention of diabetes in KRV-infected animals. The expression of IL-1beta, TNF-alpha, and IL-12 was significantly decreased in the spleen of AG-treated, KRV-infected DR-BB rats compared with PBS-treated, KRV-infected control rats. Subsequent experiments revealed that AG treatment exerted its preventive effect in KRV-infected rats by maintaining the finely tuned immune balance normally disrupted by KRV, evidenced by a significant decrease in the expression of IFN-gamma, but not IL-4, and a decrease in Th1-type chemokine receptors CCR5, CXCR3, and CXCR4. We also found that iNOS inhibition by AG decreased the KRV-induced expression of MHC class II molecules and IL-2R alpha-chain, resulting in the suppression of T cell activation, evidenced by the decreased cytolytic activity of CD8(+) T cells. We conclude that NO plays a critical immunoregulatory role by up-regulating macrophage-derived proinflammatory cytokines, up-regulating the Th1 immune response, and activating T cells, leading to type 1 diabetes after KRV infection, whereas suppression of NO production by AG treatment prevents KRV-induced autoimmune diabetes in DR-BB rats.
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Affiliation(s)
- Israel I Mendez
- Julia McFarlane Diabetes Research Centre, Department of Microbiology and Infectious Diseases, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
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Knoch KP, Bergert H, Borgonovo B, Saeger HD, Altkrüger A, Verkade P, Solimena M. Polypyrimidine tract-binding protein promotes insulin secretory granule biogenesis. Nat Cell Biol 2004; 6:207-14. [PMID: 15039777 DOI: 10.1038/ncb1099] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2003] [Accepted: 01/26/2004] [Indexed: 01/12/2023]
Abstract
Pancreatic beta-cells store insulin in secretory granules that undergo exocytosis upon glucose stimulation. Sustained stimulation depletes beta-cells of their granule pool, which must be quickly restored. However, the factors promoting rapid granule biogenesis are unknown. Here we show that beta-cell stimulation induces the nucleocytoplasmic translocation of polypyrimidine tract-binding protein (PTB). Activated cytosolic PTB binds and stabilizes mRNAs encoding proteins of secretory granules, thus increasing their translation, whereas knockdown of PTB expression by RNA interference (RNAi) results in the depletion of secretory granules. These findings may provide insight for the understanding and treatment of diabetes, in which insulin secretion is typically impaired.
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Affiliation(s)
- Klaus-Peter Knoch
- Experimental Diabetology, Carl Gustav Carus Medical School, University of Technology Dresden, Dresden 01307, Germany
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Achard S, Jean A, Lorphelin D, Amoravain M, Claret EJ. Homogeneous Assays Allow Direct "In Well" Cytokine Level Quantification. Assay Drug Dev Technol 2003; 1:181-5. [PMID: 15090145 DOI: 10.1089/154065803321537908] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
We have developed several homogeneous cytokine assays based on TR-FRET using europium cryptate- and cross-linked allophycocyanin-conjugated antibodies. Taking advantage of homogeneous assays, we have coincubated the cells with the antibody pair during the stimulation step. The results show that the presence of cells in wells at the time of reading does not alter the results. Furthermore, this experimental procedure avoids cumbersome transfer and storage steps streamlining sample analysis. Finally, it facilitates the follow-up of cytokine production.
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Affiliation(s)
- Stephanie Achard
- CIS bio international, HTRF/Bioassays, BP 81475, 30204 Bagnols-sur-Ceze Cedex, France
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