478 results on '"Bouwens, Luc"'
Search Results
202. Conversion of Human Pancreatic Acinar Cells Toward a Ductal-Mesenchymal Phenotype and the Role of Transforming Growth Factor and Activin Signaling
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De Waele, Evelien, Wauters, Elke, Ling, Zhidong, and Bouwens, Luc
- Abstract
Epithelial-mesenchymal transition may interfere with the differentiation of cultured pancreatic acinar cells toward endocrine cells. Therefore, it will be important to investigate into detail the reprogramming of human pancreatic acinar cells toward a mesenchymal phenotype: the association with acinoductal transdifferentiation, the influence of cell adhesion, and the regulation behind this process.
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- 2014
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203. Tissue localization and kinetics of pit cells or large granular lymphocytes in the liver of rats treated with biological response modifiers.
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Bouwens, Luc and Wisse, Eddie
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- 1988
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204. Quantitation, tissue distribution and proliferation kinetics of kupffer cells in normal rat liver.
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Bouwens, Luc, Baekeland, Marijke, de Zanger, Ronald, and Wisse, Eddie
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- 1986
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205. Importance of Local Proliferation in the Expanding Kupffer Cell Population of Rat Liver After Zymosan Stimulation and Partial Hepatectomy.
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Bouwens, Luc, Baekeland, Marijke, and Wisse, Eddie
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- 1984
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206. Immuno-electron microscopic characterization of large granular lymphocytes (natural killer cells) from rat liver.
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Bouwens, Luc and Wisse, Eddie
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- 1987
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207. Large granular lymphocytes or 'Pit cells' from rat liver: isolation, ultrastructural characterization and natural killer activity.
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Bouwens, Luc, Remels, Linda, Baekeland, Marijke, Van Bossuyt, Hans, and Wisse, E.
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- 1987
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208. Pit cells in the liver.
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Bouwens, Luc and Wisse, Eddie
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- 1992
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209. Origin and differentiation of hepatic natural killer cells (pit cells).
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Vanderkerken, Karin, Bouwens, Luc, de Neve, Wilfried, van den Berg, Kit, Baekeland, Marijke, Delens, Nadia, and Wisse, Eddie
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- 1993
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210. Natural cytotoxicity of rat hepatic natural killer cells and macrophages against a syngeneic colon adenocarcinoma.
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Bouwens, Luc, Jacobs, Roland, Remels, Linda, and Wisse, Eddie
- Abstract
The in vitro cytotoxic activity of two types of hepatic sinusoidal cells, i.e., natural killer (NK) cells and macrophages (Kupffer cells), was tested against a syngeneic rat colon adenocarcinoma cell line (DHD-K12). Purified hepatic NK cells (85% cells with large granular lymphocyte morphology) were spontaneously cytolytic, whereas Kupffer cells (90% pure) were not able to kill the DHD-K12 cells. This carcinoma cell line was found to be resistant to the action of mouse recombinant tumor necrosis factor which is considered as the major cytolytic molecule secreted by macrophages. However, colon carcinoma cells were readily lysed by soluble factors present in the culture supernatant of NK cells. It is postulated that hepatic NK cells, which are strategically located within the lumen of the sinusoids, may form a first line of defense to metastasizing colon carcinoma cells. [ABSTRACT FROM AUTHOR]
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- 1988
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211. Culture of adult human islet preparations with hepatocyte growth factor and 804G matrix is mitogenic for duct cells but not for beta-cells.
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Lefebvre, Veronique H., Otonkoski, Timo, Ustinov, Jarkko, Huotori, Mari-Anne, Pipeleers, Daniel G., Bouwens, Luc, Lefebvre, V H, Otonkoski, T, Ustinov, J, Huotari, M A, Pipeleers, D G, and Bouwens, L
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PANCREATIC beta cells ,HEPATOCYTE growth factor ,PHYSIOLOGY ,PROTEIN analysis ,EXTRACELLULAR space ,RNA analysis ,ANIMAL experimentation ,CARBONIC anhydrase ,CELL culture ,CELL division ,COMPARATIVE studies ,CYTOKINES ,GLUCAGON ,INSULIN ,ISLANDS of Langerhans ,RESEARCH methodology ,MEDICAL cooperation ,PANCREATIC duct ,PROINSULIN ,PROTEIN precursors ,RATS ,RECOMBINANT proteins ,RESEARCH ,RNA ,TIME ,TUMOR antigens ,EVALUATION research ,DEOXYRIBONUCLEOSIDES - Abstract
It has recently been reported that human adult beta-cells proliferate during culture on an extracellular matrix prepared from rat 804G cells and in the presence of hepatocyte growth factor (HGF). The present study compares the mitogenic effect of this condition on human beta-cells and on neighboring non-endocrine duct cells. Islet cell-enriched fractions were prepared from adult human organ donors and cultured in suspension or on 804G matrix, with or without HGF. The combination of 804G matrix and HGF increased the number of 5-bromo-2'-deoxyuridine-positive (BrdU+) cells within 48 h reaching a maximum after 4 days. In sections, virtually all BrdU+ cells were negative for insulin or glucagon and for preproinsulin mRNA but expressed the ductal cell markers cytokeratin 19 and 7, carbonic anhydrase-II, and carbohydrate antigen 19-9. After 4 days of culture, the cytokeratin 19+ ductal cells exhibited a BrdU-labeling index of 30% (P < 0.01 vs. 2% without HGF and matrix), whereas <0.1% of insulin-positive and <1% of glucagon-positive cells were labeled. Formation of bilayers with ductal cells covering the endocrine cells may cause erroneous interpretation on double positivity in unsectioned tissue. It is concluded that culture of human islet cell preparations with HGF and 804G matrix stimulates the proliferation of the duct cells but not of the underlying beta-cells. [ABSTRACT FROM AUTHOR]
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- 1998
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212. Cytokeratins as markers of ductal cell differentiation and islet neogenesis in the neonatal rat pancreas.
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Bouwens, Luc, Ren-Nian Wang, De Blay, Emmy, Pipeleers, Daniël G., Klöppel, Günter, Bouwens, L, Wang, R N, De Blay, E, Pipeleers, D G, and Klöppel, G
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- 1994
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213. Islet morphogenesis and stem cell markers
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Bouwens, Luc
- Abstract
Abstract: The mechanism of islet neogenesis remains poorly understood, despite its potential applications in regenerative or replacement therapies for the treatment of insulin-dependent diabetes. During fetal development of the mouse or rat, the majority of islet cells are formed in late gestation (E18–21) by the process of neogenesis from precursor cells. The precursor cells are organized as ducts that actively proliferate and express high levels of specific cytokeratin (CK) proteins. Transitional cells coexpressing islet hormones and CK are frequent and disappear shortly after birth, to reappear only in conditions in which pancreas or islet regeneration has been induced. Islet morphogenesis is thought to operate mainly through the budding of islet cells from ducts, followed by their migration away from the duct to form clusters. Single islet cells are indeed frequent in the fetal and regenerating pancreas, but they also occur in normal tissue, especially in the human pancreas. A different neogenic mechanism, observed in the fetal rat, consists in the proliferation of ductal cells resulting in large aggregates. Starting from the middle of the aggregate, cells differentiate into islet cells and gradually lose their proliferative activity and other ductal characteristics. In adult pancreas, islets are in close contact with at least one duct or ductule. Such a direct duct-islet axis becomes even more evident in regeneration models, such as duct ligation. In these models, a metaplastic transformation of the exocrine pancreas to so-called pseudoductal complexes is seen. Surviving exocrine cells acquire a metaplastic phenotype, which resembles the fetal protodifferentiated state. They start to express CK, the β-cell transcription factor Pdx1, the neuroendocrine/islet cell markers PGP9.5 and the CCKB receptor for gastrin, and they show pronounced proliferative activity and islet neogenesis. We hypothesize that these de-differentiated or metaplastic exocrine cells (acinar and ductal), acquire a multipotential state and can serve as islet precursors.
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- 2004
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214. Exocrine cell transdifferentiation in dexamethasone-treated rat pancreas
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Lardon, Jessy, Huyens, Niki, Rooman, Ilse, and Bouwens, Luc
- Abstract
Injured pancreatic tissue, for example, after duct ligation, undergoes remodeling, which involves the replacement of exocrine acini by duct-like structures. This acinoductal metaplasia is probably at least partly due to transdifferentiation of amylase-positive, cytokeratin-20 (CK20)-negative acinar cells into amylase-negative, CK20-positive duct-like cells. Due to the kinetics of these phenotypic changes, however, it has not been possible to demonstrate transitional stages of differentiation, which would express both markers at the same time. We took advantage of the fact that dexamethasone treatment inhibits the loss of amylase from acinar cells to demonstrate transitional cells co-expressing amylase and CK20. This was found both in vivo, where duct-ligation induced metaplasia, and in vitro, after isolation of acini. In addition, we found evidence for an acinar-to-islet conversion under the form of transitional cells co-expressing amylase and insulin. These observations strengthen the notion that fully differentiated cells, such as exocrine pancreatic cells, retain the capacity to undergo important phenotypic switches. This finding could have applications in tissue engineering or cell replacement strategies.
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- 2004
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215. In vitro comparison of various antioxidants and flavonoids from Rooibos as beta cell protectants against lipotoxicity and oxidative stress-induced cell death.
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Moens, Céline, Muller, Christo J. F., and Bouwens, Luc
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CELL death , *PANCREATIC beta cells , *FLAVONOIDS , *OXIDATIVE stress , *TYPE 2 diabetes , *GLUCOSE transporters - Abstract
Oxidative stress and lipotoxicity effects on pancreatic β cells play a major role in the pathogenesis of type 2 diabetes (T2D). Flavonoids and antioxidants are under study for their cytoprotective effects and antidiabetic potential. In this study, we aimed to compare the protective effect of the Rooibos components aspalathin, isoorientin, 3-hydroxyphloretin (3-OH) and green Rooibos extract (GRT) itself, and exendin-4 and N-acetylcysteine (NAC) as reference molecules, against lipotoxicity and oxidative stress. The insulin-producing β cell line INS1E was exposed to hydrogen peroxide or streptozotocin (STZ) to induce oxidative stress, and palmitate to induce lipotoxicity. Cell viability was assessed by a MTS cell viability assay. Antioxidant response and antiapoptotic gene expression was performed by qRT-PCR. Glucose transporter 2 (GLUT 2) transporter inhibition was assessed through 2-NBDG uptake. GRT and the flavonoids aspalathin and 3-hydroxyphloretin offered significant protection against oxidative stress and lipotoxicity. GRT downregulated expression of pro-apoptotic genes Txnip and Ddit3. The flavonoids aspalathin and 3-hydroxyphloretin also downregulated these genes and in addition upregulated expression of antioxidant response genes Hmox1, Nqo1 and Sod1. Isoorientin gave no cytoprotection. Cytoprotection by Rooibos components was significantly higher than by NAC or exendin-4. Rooibos components strongly protect INS1E β cells against diabetogenic stress. Cytoprotection was associated with the upregulation of antioxidant response genes of the NRF2/KEAP1 pathway or suppression of the TXN system. The Rooibos molecules offered better protection against these insults than exendin-4 and NAC, making them interesting candidates as β cell cytoprotectants for therapeutic or nutraceutical applications. [ABSTRACT FROM AUTHOR]
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- 2022
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216. SSEA4: a marker leading the way towards curing diabe.
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Bouwens, Luc
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- 2012
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217. Retraction Note: Transient cytokine treatment induces acinar cell reprogramming and regenerates functional beta cell mass in diabetic mice.
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Baeyens, Luc, Lemper, Marie, Leuckx, Gunter, De Groef, Sofie, Bonfanti, Paola, Stangé, Geert, Shemer, Ruth, Nord, Christoffer, Scheel, David W., Pan, Fong C., Ahlgren, Ulf, Gu, Guoqiang, Stoffers, Doris A., Dor, Yuval, Ferrer, Jorge, Gradwohl, Gerard, Wright, Christopher V. E., Van de Casteele, Mark, German, Michael S., and Bouwens, Luc
- Abstract
This article has been retracted; see accompanying Retraction Note, which can be accessed via a link at the top of the paper. [ABSTRACT FROM AUTHOR]
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- 2020
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218. Isolation, purification and culture of sinusoidal liver cells
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Bouwens, Luc, Wisse, Eduard, Van Bossuyt, Hans, Balabaud, C., Bioulac-Sage, P., Cell Biology and Histology, and Vrije Universiteit Brussel
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- 1988
219. Hepatic pit cells have natural cytotoxic (NC) activity against solid tumor-derived target cells
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Bouwens, Luc, Wisse, Eduard, Knook, Dick, Decker, K., Cell Biology and Histology, and Vrije Universiteit Brussel
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- 1989
220. Characterization and population kinetics of liverassociated large granular lymphocytes (Natural Killer cells)
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Bouwens, Luc, Wisse, Eduard, Dornand, J., Mani, J.c., Cell Biology and Histology, and Vrije Universiteit Brussel
- Published
- 1988
221. Structure and function of the hepatic sunusoidal wall
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Bouwens, Luc, Wisse, Eduard, Motta, P., Cell Biology and Histology, and Vrije Universiteit Brussel
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- 1988
222. A balanced view on the origin of Kupffer cells.Cells of the Hepatic Sinusoid
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Baekeland, Marijke, Bouwens, Luc, Wisse, Eduard, Knook, Dick, Kirk, A., Cell Biology and Histology, and Vrije Universiteit Brussel
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- 1986
223. Ultrastructure of human hepatic pit cells
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Bouwens, Luc, Wisse, Eduard, Brouwer, A., Knook, Dick, Decker, K., Cell Biology and Histology, and Vrije Universiteit Brussel
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- 1989
224. Sinusoidal cells anno 1988: Reviewing the 4th International Kupffer Cell Symposium
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Bouwens, Luc, Geerts, Albert, Vanderkerken, Karin, Wisse, Eduard, Van Bossuyt, Hans, Van Goethem, Freddy, Knook, Dick, Decker, K., Cell Biology and Histology, and Vrije Universiteit Brussel
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- 1989
225. Cell population kinetics of Kupffer cells during the onset of fibrosis in rat liver by chronic carbon tetrachloride administration
- Author
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Geerts, Albert, primary, Schellinck, Paul, additional, Bouwens, Luc, additional, and Wisse, Eddie, additional
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- 1988
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226. Discovery analysis of cancer-relevant genes uniquely expressed in dedifferentiated human acinar cells and not in duct cells.
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Backx, Elyne, Wauters, Elke, Van Bulck, Mathias, Baldan, Jonathan, Ling, Zhidong, Bouwens, Luc, Jacquemin, Patrick, Houbracken, Isabelle, and Rooman, Ilse
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- 2018
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227. Diabetes: β cells at last.
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Mfopou, Josué K and Bouwens, Luc
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- 2015
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228. β cells at last.
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Mfopou, Josué K. and Bouwens, Luc
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STEM cell research , *TYPE 1 diabetes , *PANCREATIC beta cells , *PLURIPOTENT stem cells , *CELL lines - Abstract
The article discusses research being done on the role of stem-cell-derived β (SCβ) cells in patients with type 1 diabetes mellitus. It references the study "Generation of Functional Human Pancreatic β Cells in vitro," by F. W. Pagliuca et al. in the 2014 issue of "Cells." The researchers considered various variables including the difference between SCβ cell and human pluripotent stem cells (hPSC), cell lines and transplantation of the SCβ cells.
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- 2015
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229. Noggin, Retinoids, and Fibroblast Growth Factor Regulate Hepatic or Pancreatic Fate of Human Embryonic Stem Cells.
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Mfopou, Josué Kunjom, Chen, Bing, Mateizel, Ileana, Sermon, Karen, and Bouwens, Luc
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FIBROBLAST growth factors ,PEOPLE with diabetes ,CELL differentiation ,BIOMARKERS ,EMBRYONIC stem cells ,STEM cell transplantation ,BONE morphogenetic proteins ,TRETINOIN - Abstract
Background & Aims: New sources of β cells are needed to develop cell therapies for patients with diabetes. An in vitro, sequential method has been developed to derive pancreatic progenitors, but this technique has not been used for other cell lines. We investigated whether definitive endoderm derived from human embryonic stem (hES) cells might be used to create β cells. Methods: Five hES cell lines were induced to form pancreatic progenitors and analyzed for pancreas markers. Cells were incubated with a bone morphogenetic protein (BMP) antagonist, retinoids, a Hedgehog antagonist, or fibroblast growth factor (FGF) and phenotypes were analyzed. Results: Four hES cell lines sequentially generated definitive endoderm, primitive gut, and posterior foregut equivalents, as described previously. However, functional hepatocytes, rather than pancreas progenitors, developed. Consistent with liver development, FGF and BMP signaling pathways were involved in this process; their inhibition disrupted hepatocyte differentiation. During early stages of development, exposure of cells to noggin and retinoid acid, followed by FGF10, generated pancreatic cells (PDX1+; 50%−80%) that coexpressed FOXA2, HNF6, and SOX9. Conclusions: These findings demonstrate the combined functions of endogenous BMP and supplemented FGF in inducing differentiation of hepatocytes from hES cells and the ability to shift developmental pathways from hepatic to pancreatic cell differentiation. Although additional signals appear to be required for full specification of PDX1
+ early pancreatic progenitors (via PTF1a and NKX6.1 coexpression), these findings indicate the signaling pathways required for differentiation of bipotential progenitors. [Copyright &y& Elsevier]- Published
- 2010
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230. Notch Signaling as Gatekeeper of Rat Acinar-to-β-Cell Conversion in Vitro.
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Baeyens, Luc, Bonné, Stefan, Bos, Tomas, Rooman, Ilse, Peleman, Cindy, Lahoutte, Tony, German, Michael, Heimberg, Harry, and Bouwens, Luc
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NOTCH genes ,CELLULAR signal transduction ,PANCREATIC acinar cells ,PANCREATIC beta cells ,LABORATORY rats ,EPIDERMAL growth factor ,CELLULAR therapy - Abstract
Background & Aims: Exocrine acinar cells in the pancreas are highly differentiated cells that retain a remarkable degree of plasticity. After isolation and an initial phase of dedifferentiation in vitro, rodent acinar cells can convert to endocrine β-cells when cultured in the presence of appropriate factors. The mechanisms regulating this phenotypic conversion are largely unknown. Methods: Using rat acinar cell cultures, we studied the role of Notch signaling in a model of acinar-to-β-cell conversion. Results: We report a novel lectin-based cell labeling method to demonstrate the acinar origin of newly formed insulin-expressing β-cells. This method allows for specific tracing of the acinar cells. We demonstrate that growth factor-induced conversion of adult acinar cells to β-cells is negatively regulated by Notch1 signaling. Activated Notch1 signaling prevents the reexpression of the proendocrine transcription factor Neurogenin-3, the key regulator of endocrine development in the embryonic pancreas. Interfering with Notch1 signaling allows modulating the acinar cell susceptibility to the differentiation-inducing factors. Its inhibition significantly improves β-cell neoformation with approximately 30% of acinar cells that convert to β-cells. The newly formed β-cells mature when transplanted ectopically and are capable of restoring normal blood glycemia in diabetic recipients. Conclusions: We report for the first time an efficient way to reprogram one third of the acinar cells to β-cells by adult cell type conversion. This could find application in cell replacement therapy of type 1 diabetes, provided that it can be translated from rodent to human models. [Copyright &y& Elsevier]
- Published
- 2009
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231. Fractionated Radiation Severely Reduces the Number of CD8+ T Cells and Mature Antigen Presenting Cells Within Lung Tumors.
- Author
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Reijmen, Eva, De Mey, Sven, De Mey, Wout, Gevaert, Thierry, De Ridder, Kirsten, Locy, Hanne, Martens, Sandrina, De Blay, Emmy, Bouwens, Luc, Debie, Pieterjan, Breckpot, Karine, De Grève, Jacques, De Ridder, Mark, Goyvaerts, Cleo, Reijmen, E, De Mey, S, De Mey, W, Gevaert, T, De Ridder, K, and Locy, H
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ANTIGEN presenting cells , *REGULATORY T cells , *T cells , *MYELOID cells , *LUNG tumors , *RESEARCH , *RESEARCH methodology , *ANIMAL experimentation , *MEDICAL cooperation , *EVALUATION research , *COMPARATIVE studies , *MICE - Abstract
Purpose: The combination of standard-of-care radiation therapy (RT) with immunotherapy is moving to the mainstream of non-small cell lung cancer treatment. Multiple preclinical studies reported on the CD8+ T cell stimulating properties of RT, resulting in abscopal therapeutic effects. A literature search demonstrates that most preclinical lung cancer studies applied subcutaneous lung tumor models. Hence, in-depth immunologic evaluation of clinically relevant RT in orthotopic lung cancer models is lacking.Methods and Materials: We studied the therapeutic and immunologic effects of low-dose fractionated RT on lungs from C57BL/6 mice, challenged 2 weeks before with firefly luciferase expressing Lewis lung carcinoma cells via the tail vein. Low-dose fractionation was represented by 4 consecutive daily fractions of image guided RT at 3.2 Gy.Results: We showed reduced lung tumor growth upon irradiation using in vivo bioluminescence imaging and immunohistochemistry. Moreover, significant immunologic RT-induced changes were observed in irradiated lungs and in the periphery (spleen and blood). First, a significant decrease in the number of CD8+ T cells and trends toward more CD4+ and regulatory T cells were seen after RT in all evaluated tissues. Notably, only in the periphery did the remaining CD8+ T cells show a more activated phenotype. In addition, a significant expansion of neutrophils and monocytes was observed upon RT locally and systemically. Locally, RT increased the influx of tumor-associated macrophages and conventional type 2 dendritic cells, whereas the alveolar macrophages and conventional type 1 DCs dramatically decreased. Functionally, these antigen-presenting cells severely reduced their CD86 expression, suggesting a reduced capacity to induce potent immunity.Conclusions: Our results imply that low-dose fractionated RT of tumor-bearing lung tissue shifts the immune cell balance toward an immature myeloid cell dominating profile. These data argue for myeloid cell repolarizing strategies to enhance the abscopal effects in patients with non-small cell lung cancer treated with fractionated RT. [ABSTRACT FROM AUTHOR]- Published
- 2021
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232. Contribution of ductal cells to cytokine responses by human pancreatic islets.
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Pavlovic, Dejan, Chen, Meng-Chi, Bouwens, Luc, Eizirik, Decio L., Pipeleers, Daniel, Pavlovic, D, Chen, M C, Bouwens, L, Eizirik, D L, and Pipeleers, D
- Subjects
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PANCREATIC beta cells , *DIABETES , *CYTOKINES , *NITRIC oxide , *PHYSIOLOGY , *RNA metabolism , *CELL culture , *COMPARATIVE studies , *IMMUNOHISTOCHEMISTRY , *ISLANDS of Langerhans , *RESEARCH methodology , *MEDICAL cooperation , *NITRITES , *OXIDOREDUCTASES , *PANCREATIC duct , *RESEARCH , *EVALUATION research - Abstract
In type 1 diabetes, autoimmune destruction of pancreatic beta-cells has been attributed to cytokines released from infiltrating immunocytes. Exposure of isolated islets to cytokines leads to nitric oxide (NO) production, which can damage beta-cells. Because ductal cells are closely associated with human beta-cells, we examined whether they can contribute to this process. Isolated human ductal cells were cultured for 48 h with various cytokines. The combination of interleukin-1beta (IL-1beta) plus interferon-gamma (IFN-gamma) increased nitric oxide production 12-fold while stimulating mRNA expression of inducible nitric oxide synthase (iNOS). In this condition, 10-20% of cells positive for the cytokeratin-19 duct marker also stained positive for iNOS protein, whereas no positive cells were found in control preparations. Comparison of the magnitude of iNOS mRNA expression and nitric oxide production in these cells with that in isolated human islets suggests that >50% of total islet nitric oxide production might originate from associated ductal cells. It is concluded that ductal cells are a potential source of nitric oxide production in human islets infiltrated by cytokine-releasing immunocytes. [ABSTRACT FROM AUTHOR]
- Published
- 1999
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233. Adult human pancreatic acinar cells dedifferentiate into an embryonic progenitor-like state in 3D suspension culture.
- Author
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Baldan, Jonathan, Houbracken, Isabelle, Rooman, Ilse, and Bouwens, Luc
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- 2019
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234. Circulating microRNA-375 as biomarker of pancreatic beta cell death and protection of beta cell mass by cytoprotective compounds.
- Author
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Song, Imane, Roels, Sarah, Martens, Geert A., and Bouwens, Luc
- Subjects
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PANCREATIC beta cells , *MICRORNA , *CELL death , *CYTOPROTECTION , *BLOOD plasma , *REVERSE transcriptase polymerase chain reaction - Abstract
Objective: Previous studies demonstrated that circulating microRNA-375 (miR-375) is a suitable plasma biomarker for real-time detection of beta cell death. The present study evaluated the use of this biomarker to assess the beta cytoprotective effect of phenylpropenoic acid glucoside (PPAG), which was previously demonstrated to protect beta cells against various types of injury, and of exendin-4, which is an established antidiabetic drug. Methods: PPAG or exendin-4 were administered in mice treated with streptozotocin (STZ) to acutely induce beta cell death. Beta cell mass and apoptotic death were measured in pancreatic tissue sections. Circulating miR-375 was measured in blood plasma by RT-qPCR. The release of miR-375 was also measured in vitro by MIN-6 beta cells. Results: Administration of STZ resulted in measurable circulating levels of miR-375, a decrease in beta cell mass and increase in frequency of apoptotic beta cells. In vitro, there was a good correlation between miR-375 release and the extent of beta cell death. Treatment of mice with PPAG or exendin-4 significantly attenuated STZ-induced loss of beta cell mass and beta cell apoptosis, and normalized the blood level of miR-375. Conclusions: These findings show the potential use of serological miR-375 measurements to evaluate the beta cytoprotective effect of (potential) antidiabetic drugs in vivo. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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235. Co-localization of acinar markers and insulin in pancreatic cells of subjects with type 2 diabetes.
- Author
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Masini, Matilde, Marselli, Lorella, Himpe, Eddy, Martino, Luisa, Bugliani, Marco, Suleiman, Mara, Boggi, Ugo, Filipponi, Franco, Occhipinti, Margherita, Bouwens, Luc, De Tata, Vincenzo, and Marchetti, Piero
- Subjects
- *
PANCREATIC beta cells , *TYPE 2 diabetes , *PEOPLE with diabetes , *ORGAN donors , *AMYLASES , *CARBOXYPEPTIDASES - Abstract
To search for clues suggesting that beta cells may generate by transdifferentiation in humans, we assessed the presence of cells double positive for exocrine (amylase, carboxypeptidase A) and endocrine (insulin) markers in the pancreas of non-diabetic individuals (ND) and patients with type 2 diabetes (T2D). Samples from twelve ND and twelve matched T2D multiorgan donors were studied by electron microscopy, including amylase and insulin immunogold labeling; carboxypeptidase A immunofluorescence light microscopy assessment was also performed. In the pancreas from four T2D donors, cells containing both zymogen-like and insulin-like granules were observed, scattered in the exocrine compartment. Nature of granules was confirmed by immunogold labeling for amylase and insulin. Double positive cells ranged from 0.82 to 1.74 per mm2, corresponding to 0.26±0.045% of the counted exocrine cells. Intriguingly, cells of the innate immune systems (mast cells and/or macrophages) were adjacent to 33.3±13.6% of these hybrid cells. No cells showing co-localization of amylase and insulin were found in ND samples by electron microscopy. Similarly, cells containing both carboxypeptidase A and insulin were more frequently observed in the diabetic pancreata. These results demonstrate more abundant presence of cells containing both acinar markers and insulin in the pancreas of T2D subjects, which suggests possible conversion from one cellular type to the other and specific association with the diseased condition. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
236. Differential plasticity and fate of brain-resident and recruited macrophages during the onset and resolution of neuroinflammation.
- Author
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De Vlaminck, Karen, Van Hove, Hannah, Kancheva, Daliya, Scheyltjens, Isabelle, Pombo Antunes, Ana Rita, Bastos, Jonathan, Vara-Perez, Monica, Ali, Leen, Mampay, Myrthe, Deneyer, Lauren, Miranda, Juliana Fabiani, Cai, Ruiyao, Bouwens, Luc, De Bundel, Dimitri, Caljon, Guy, Stijlemans, Benoît, Massie, Ann, Van Ginderachter, Jo A., Vandenbroucke, Roosmarijn E., and Movahedi, Kiavash
- Subjects
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MACROPHAGES , *GENE expression profiling , *NEUROINFLAMMATION , *BORDERLANDS , *IMMUNE response , *NEUROCYSTICERCOSIS - Abstract
Microglia and border-associated macrophages (BAMs) are brain-resident self-renewing cells. Here, we examined the fate of microglia, BAMs, and recruited macrophages upon neuroinflammation and through resolution. Upon infection, Trypanosoma brucei parasites invaded the brain via its border regions, triggering brain barrier disruption and monocyte infiltration. Fate mapping combined with single-cell sequencing revealed microglia accumulation around the ventricles and expansion of epiplexus cells. Depletion experiments using genetic targeting revealed that resident macrophages promoted initial parasite defense and subsequently facilitated monocyte infiltration across brain barriers. These recruited monocyte-derived macrophages outnumbered resident macrophages and exhibited more transcriptional plasticity, adopting antimicrobial gene expression profiles. Recruited macrophages were rapidly removed upon disease resolution, leaving no engrafted monocyte-derived cells in the parenchyma, while resident macrophages progressively reverted toward a homeostatic state. Long-term transcriptional alterations were limited for microglia but more pronounced in BAMs. Thus, brain-resident and recruited macrophages exhibit diverging responses and dynamics during infection and resolution. [Display omitted] • T. brucei parasites invade the brain via its borders and evoke macrophage expansion • Brain-resident and blood-recruited macrophages show divergent responses • Upon disease resolution, recruited macrophages rapidly disappear and do not engraft • While disease-associated microglia revert toward homeostasis, BAMs remain altered De Vlaminck et al. examine the fate of microglia, border-associated macrophages, and recruited macrophages upon Trypanosoma brucei infection and resolution of neuroinflammation. They show how different types of brain macrophages orchestrate the immune response to invading parasites, revealing that brain-resident and recruited macrophages exhibit diverging responses and dynamics during infection and the return to homeostasis. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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237. Phenylpropenoic Acid Glucoside from Rooibos Protects Pancreatic Beta Cells against Cell Death Induced by Acute Injury.
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Himpe, Eddy, Cunha, Daniel A., Song, Imane, Bugliani, Marco, Marchetti, Piero, Cnop, Miriam, and Bouwens, Luc
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PHENYLPROPIONATES , *PANCREATIC beta cells , *CELL death , *GLUCOSIDES , *ROOIBOS tea - Abstract
Objective: Previous studies demonstrated that a phenylpropenoic acid glucoside (PPAG) from rooibos (Aspalathus linearis) extract had anti-hyperglycemic activity and significant protective effects on the pancreatic beta cell mass in a chronic diet-induced diabetes model. The present study evaluated the cytoprotective effect of the phytochemical on beta cells exposed to acute cell stress. Methods: Synthetically prepared PPAG was administered orally in mice treated with a single dose of streptozotocin to acutely induce beta cell death and hyperglycemia. Its effect was assessed on beta cell mass, proliferation and apoptotic cell death. Its cytoprotective effect was also studied in vitro on INS-1E beta cells and on human pancreatic islet cells. Results: Treatment with the phytochemical PPAG protected beta cells during the first days after the insult against apoptotic cell death, as evidenced by TUNEL staining, and prevented loss of expression of anti-apoptotic protein BCL2 in vivo. In vitro, PPAG protected INS-1E beta cells from streptozotocin-induced apoptosis and necrosis in a BCL2-dependent and independent way, respectively, depending on glucose concentration. PPAG also protected human pancreatic islet cells against the cytotoxic action of the fatty acid palmitate. Conclusions: These findings show the potential use of PPAG as phytomedicine which protects the beta cell mass exposed to acute diabetogenic stress. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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238. Acinar phenotype is preserved in human exocrine pancreas cells cultured at low temperature: implications for lineage-tracing of β-cell neogenesis.
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Mfopou, K. Mfopou, Houbracken, Isabelle, Wauters, Elke, Mathijs, Iris, Song, Imane, Himpe, Eddy, Baldan, Jonathan, Heimberg, Harry, and Bouwens, Luc
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PANCREATIC acinar cells , *PHENOTYPES , *CELL culture , *LOW temperatures , *CILIARY neurotrophic factor , *EPIDERMAL growth factor , *CELL morphology - Abstract
The regenerative medicine field is expanding with great successes in laboratory and preclinical settings. Pancreatic acinar cells in diabetic mice were recently converted into β-cells by treatment with ciliary neurotrophic factor (CNTF) and epidermal growth factor (EGF). This suggests that human acinar cells might become a cornerstone for diabetes cell therapy in the future, if they can also be converted into glucose-responsive insulin-producing cells. Presently, studying pancreatic acinar cell biology in vitro is limited by their high plasticity, as they rapidly lose their phenotype and spontaneously transdifferentiate to a duct-like phenotype in culture. We questioned whether human pancreatic acinar cell phenotype could be preserved in vitro by physico-chemical manipulations and whether this could be valuable in the study of β-cell neogenesis. We found that culture at low temperature (4°C) resulted in the maintenance of morphological and molecular acinar cell characteristics. Specifically, chilled acinar cells did not form the spherical clusters observed in controls (culture at 37°C), and they maintained high levels of acinar-specific transcripts and proteins. Five-day chilled acinar cells still transdifferentiated into duct-like cells upon transfer to 37°C. Moreover, adenoviral-mediated gene transfer evidenced an active Amylase promoter in the 7-day chilled acinar cells, and transduction performed in chilled conditions improved acinar cell labelling. Together, our findings indicate the maintenance of human pancreatic acinar cell phenotype at low temperature and the possibility to efficiently label acinar cells, which opens new perspectives for the study of human acinar-to-β-cell transdifferentiation. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
239. Beta Cell Mass Restoration in Alloxan-Diabetic Mice Treated with EGF and Gastrin.
- Author
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Song, Imane, Patel, Oelfah, Himpe, Eddy, Muller, Christo J. F., and Bouwens, Luc
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ALLOXAN diabetes , *PANCREATIC beta cells , *EPIDERMAL growth factor , *GASTRIN , *REGENERATION (Biology) , *LABORATORY mice , *THERAPEUTICS - Abstract
One week of treatment with EGF and gastrin (EGF/G) was shown to restore normoglycemia and to induce islet regeneration in mice treated with the diabetogenic agent alloxan. The mechanisms underlying this regeneration are not fully understood. We performed genetic lineage tracing experiments to evaluate the contribution of beta cell neogenesis in this model. One day after alloxan administration, mice received EGF/G treatment for one week. The treatment could not prevent the initial alloxan-induced beta cell mass destruction, however it did reverse glycemia to control levels within one day, suggesting improved peripheral glucose uptake. In vitro experiments with C2C12 cell line showed that EGF could stimulate glucose uptake with an efficacy comparable to that of insulin. Subsequently, EGF/G treatment stimulated a 3-fold increase in beta cell mass, which was partially driven by neogenesis and beta cell proliferation as assessed by beta cell lineage tracing and BrdU-labeling experiments, respectively. Acinar cell lineage tracing failed to show an important contribution of acinar cells to the newly formed beta cells. No appearance of transitional cells co-expressing insulin and glucagon, a hallmark for alpha-to-beta cell conversion, was found, suggesting that alpha cells did not significantly contribute to the regeneration. An important fraction of the beta cells significantly lost insulin positivity after alloxan administration, which was restored to normal after one week of EGF/G treatment. Alloxan-only mice showed more pronounced beta cell neogenesis and proliferation, even though beta cell mass remained significantly depleted, suggesting ongoing beta cell death in that group. After one week, macrophage infiltration was significantly reduced in EGF/G-treated group compared to the alloxan-only group. Our results suggest that EGF/G-induced beta cell regeneration in alloxan-diabetic mice is driven by beta cell neogenesis, proliferation and recovery of insulin. The glucose-lowering effect of the treatment might play an important role in the regeneration process. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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240. A Standardized Method for In Vivo Mouse Pancreas Imaging and Semiquantitative β Cell Mass Measurement by Dual Isotope SPECT.
- Author
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Mathijs, Iris, Xavier, Catarina, Peleman, Cindy, Caveliers, Vicky, Brom, Maarten, Gotthardt, Martin, Herrera, Pedro, Lahoutte, Tony, and Bouwens, Luc
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- *
PANCREAS radiography , *ANIMAL models of diabetes , *DIAGNOSTIC use of radiolabeled blood cells , *SINGLE-photon emission computed tomography , *PANCREATIC beta cells , *DISEASE progression - Abstract
Purpose: In order to evaluate future β cell tracers in vivo, we aimed to develop a standardized in vivo method allowing semiquantitative measurement of a prospective β cell tracer within the pancreas. Procedures: 2-[I]Iodo- l-phenylalanine ([I]IPA) and [Lys([In]DTPA)]exendin-3 ([In]Ex3) pancreatic uptake and biodistribution were evaluated using SPECT, autoradiography, and an ex vivo biodistribution study in a controlled unilaterally nephrectomized mouse β cell depletion model. Semiquantitative measurement of the imaging results was performed using [I]IPA to delineate the pancreas and [In]Ex3 as a β cell tracer. Results: The uptake of [I]IPA was highest in the pancreas. Aside from the kidneys, the uptake of [In]Ex3 was highest in the pancreas and lungs. Autoradiography showed only uptake of [In]Ex3 in insulin-expressing cells. Semiquantitative measurement of [In]Ex3 in the SPECT images based on the delineation of the pancreas with [I]IPA showed a high correlation with the [In]Ex3 uptake data of the pancreas obtained by dissection. A strong positive correlation was observed between the relative insulin positive area and the pancreas-to-blood ratios of [In]Ex3 uptake as determined by counting with a gamma counter and the semiquantitative analysis of the SPECT images. Conclusions: [I]IPA is a promising tracer to delineate pancreatic tissue on SPECT images. It shows a high uptake in the pancreas as compared to other abdominal tissues. This study also demonstrates the feasibility and accuracy to measure the β cell mass in vivo in an animal model of diabetes. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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- View/download PDF
241. FGF signaling via MAPK is required early and improves Activin A-induced definitive endoderm formation from human embryonic stem cells
- Author
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Bouwens, Luc [Cell Differentiation Unit, Diabetes Research Center, Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels (Belgium)]
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- 2012
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- View/download PDF
242. Specific targeting of atherosclerotic plaques in ApoE(-/-) mice using a new Camelid sdAb binding the vulnerable plaque marker LOX-1.
- Author
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De Vos, Jens, Mathijs, Iris, Xavier, Catarina, Massa, Sam, Wernery, Ulrich, Bouwens, Luc, Lahoutte, Tony, Muyldermans, Serge, and Devoogdt, Nick
- Abstract
Purpose: Molecular imaging has the potential to provide quantitative information about specific biological aspects of developing atherosclerotic lesions. This requires the generation of reliable, highly specific plaque tracers. This study reports a new camelid single-domain antibody fragment (sdAb) targeting the Lectin-like oxidized low-density lipoprotein receptor (LOX-1), a biomarker for the detection and molecular phenotyping of vulnerable atherosclerotic plaques.Procedures: A camelid sdAb was generated and selected for high affinity binding to LOX-1. Ex vivo biodistribution and in vivo single photon emission computed tomography (SPECT)/computed tomography (CT) imaging studies were performed in wild-type mice and in fat-fed atherosclerotic apolipoprotein E-deficient mice with (99m)Tc-labeled sdAbs. Gamma-counting and autoradiography analyses were performed on dissected aorta segments with different degrees of plaque burden. The specificity of the LOX-1-targeting sdAb was evaluated by blocking with unlabeled sdAb or by comparison with a nontargeting (99m)Tc-labeled control sdAb.Results: We generated a sdAb binding LOX-1 with a KD of 280 pM ± 62 pM affinity. After (99m)Tc-labeling, the tracer had radiochemical purity higher then 99 % and retained specificity in in vitro binding studies. Tracer blood clearance was fast with concomitant high kidney retention. At 3 h after injection, uptake in tissues other than plaques was low and not different than background, suggesting a restricted expression pattern of LOX-1. Conversely, uptake in aortic segments increased with plaque content and was due to specific LOX-1 binding. In vivo SPECT/CT imaging 160 min after injection in atherosclerotic mice confirmed specific targeting of LOX-1-expressing aortic plaques.Conclusions: The LOX-sdAb specifically targets LOX-1-expressing atherosclerotic plaques within hours after injection. The possibility to image LOX-1 rapidly after administration combined with the favourable biodistribution of a sdAb are beneficial for molecular phenotyping of atherosclerotic plaques and the generation of a future prognostic tracer. [ABSTRACT FROM AUTHOR]- Published
- 2014
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243. Transient cytokine treatment induces acinar cell reprogramming and regenerates functional beta cell mass in diabetic mice.
- Author
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Baeyens, Luc, Lemper, Marie, Leuckx, Gunter, De Groef, Sofie, Bonfanti, Paola, Stangé, Geert, Shemer, Ruth, Nord, Christoffer, Scheel, David W, Pan, Fong C, Ahlgren, Ulf, Gu, Guoqiang, Stoffers, Doris A, Dor, Yuval, Ferrer, Jorge, Gradwohl, Gerard, Wright, Christopher V E, Van de Casteele, Mark, German, Michael S, and Bouwens, Luc
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- *
THERAPEUTIC use of cytokines , *PANCREATIC acinar cells , *DIABETES , *EPIDERMAL growth factor , *NEUROGENIN 3 - Abstract
Reprogramming of pancreatic exocrine cells into cells resembling beta cells may provide a strategy for treating diabetes. Here we show that transient administration of epidermal growth factor and ciliary neurotrophic factor to adult mice with chronic hyperglycemia efficiently stimulates the conversion of terminally differentiated acinar cells to beta-like cells. Newly generated beta-like cells are epigenetically reprogrammed, functional and glucose responsive, and they reinstate normal glycemic control for up to 248 d. The regenerative process depends on Stat3 signaling and requires a threshold number of Neurogenin 3 (Ngn3)-expressing acinar cells. In contrast to previous work demonstrating in vivo conversion of acinar cells to beta-like cells by viral delivery of exogenous transcription factors, our approach achieves acinar-to-beta-cell reprogramming through transient cytokine exposure rather than genetic modification. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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244. Peroxiredoxin-I Maintains Inflammation during Pancreatitis.
- Author
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Buckens, Hortense, Pirenne, Sophie, Achouri, Younes, Baldan, Jonathan, Dahou, Hajar, Bouwens, Luc, Lemaigre, Frédéric, Jacquemin, Patrick, and Assi, Mohamad
- Subjects
- *
PANCREATITIS , *INFLAMMATION - Published
- 2022
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- View/download PDF
245. Role of BMP Signaling in Pancreatic Progenitor Differentiation from Human Embryonic Stem Cells.
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Sui, Lina, Geens, Mieke, Sermon, Karen, Bouwens, Luc, and Mfopou, Josué
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BONE morphogenetic proteins , *PROGENITOR cells , *CELL differentiation , *EMBRYONIC stem cells , *PANCREAS , *CELLULAR signal transduction , *TREATMENT of diabetes , *ANATOMY - Abstract
Transplantation of pancreatic progenitors derived from human embryonic stem cells (hESCs) is a promising way to treat diabetes. Strategies to obtain the required cell mass would rely on the up scaling of current differentiation protocols, or the proliferation of committed progenitors. We aimed at finding conditions that maintain a proliferating pancreatic progenitor pool and we assessed the role of BMP4 signaling in this process. hESCs were differentiated into PDX1 positive pancreatic progenitor stage following our established protocol with few modifications, and then the progenitor cells were passaged in a defined proliferation medium (PM). During passage, the effect of BMP4 signaling on the differentiation and proliferation of pancreatic progenitors was examined by RT-PCR and immunofluorescence analysis. We found that PDX1 positive pancreatic progenitors proliferated and gained NKX6.1 expression in the PM, whereas they failed to express NKX6.1 if BMP signaling was inhibited with Noggin. In this latter condition, part of the progenitors rather generated pro-endocrine cells denoted by NGN3 and synaptophysin expression. On the contrary, addition of BMP4 to the PM promoted the early derivation of PDX1 and NKX6.1 coexpressing pancreatic progenitors. Our findings are in line with mouse pancreas development, and indicate that BMP4 signaling is required for the derivation and maintenance of hESC-derived PDX1+NKX6.1+ pancreatic progenitors. These results are instructive for guiding the development of an efficient pancreas differentiation protocol in view of diabetes cell replacement therapy. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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- View/download PDF
246. Gene delivery to pancreatic exocrine cells in vivo and in vitro.
- Author
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Houbracken, Isabelle, Baeyens, Luc, Ravassard, Philippe, Heimberg, Harry, and Bouwens, Luc
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GENETIC transformation , *GENE expression , *BACTERIOPHAGES , *LEUCOCYTES , *ANIMAL models in research - Abstract
Background: Effective gene transfer to the pancreas or to pancreatic cells has remained elusive although it is essential for studies of genetic lineage tracing and modulation of gene expression. Different transduction methods and viral vectors were tested in vitro and in vivo, in rat and mouse pancreas. Results: For in vitro transfection/transduction of rat exocrine cells lipofection reagents, adenoviral vectors, and Mokola- and VSV-G pseudotyped lentiviral vectors were used. For in vivo transduction of mouse and rat pancreas adenoviral vectors and VSV-G lentiviral vectors were injected into the parenchymal tissue. Both lipofection of rat exocrine cell cultures and transduction with Mokola pseudotyped lentiviral vectors were inefficient and resulted in less than 4% EGFP expressing cells. Adenoviral transduction was highly efficient but its usefulness for gene delivery to rat exocrine cells in vitro was hampered by a drastic increase in cell death. In vitro transduction of rat exocrine cells was most optimal with VSV-G pseudotyped lentiviral vectors, with stable transgene expression, no significant effect on cell survival and about 40% transduced cells. In vivo, pancreatic cells could not be transduced by intra-parenchymal administration of lentiviral vectors in mouse and rat pancreas. However, a high efficiency couldbe obtained by adenoviral vectors, resulting in transient transduction of mainly exocrine acinar cells. Injection in immune-deficient animals diminished leukocyte infiltration and prolonged transgene expression. Conclusions: In summary, our study remarkably demonstrates that transduction of pancreatic exocrine cells requires lentiviral vectors in vitro but adenoviral vectors in vivo. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
247. Adult pancreatic acinar cells dedifferentiate to an embryonic progenitor phenotype with concomitant activation of a senescence programme that is present in chronic pancreatitis.
- Author
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Pinho, Andreia V., Rooman, Ilse, Reichert, Maximilian, De Medts, Nele, Bouwens, Luc, Rustgi, Anil K., and Real, Francisco X.
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PANCREATIC acinar cells , *PANCREATITIS , *DISEASES in older people , *PHENOTYPES , *EPITHELIAL cells - Abstract
Objective Acinar cells display plasticity in vitro and in vivo and can activate a variety of differentiation programmes that may contribute to pancreatic diseases. The aims were to determine: (1) the differentiation potential of acinar cells under conditions which favour stem cell survival, and (2) its relationship to the phenotypes acquired by pancreatic epithelial cells in chronic pancreatitis. Design Murine acinar cells were cultured in suspension and their molecular phenotype was characterised by qRT-PCR, chromatin immunoprecipitation, immunocytochemistry and global transcriptome analysis. These findings were compared to the changes occurring in experimental chronic pancreatitis induced by pancreatic duct ligation and chronic caerulein administration. Results Acinar cells in suspension culture acquired a dedifferentiated phenotype characteristic of pancreatic embryonic progenitors, consisting of the co-expression of Ptf1a and Pdx1, presence of an embryonic-type PTF1 transcriptional complex, activation of the Notch pathway, and expression of additional pancreatic progenitor cell markers such as CpA1, Sox9 and Hnf1b. A senescence programme, associated with activation of Ras and ERK signalling, limited the proliferative capacity of the cells. A similar progenitor-like phenotype with activation of a senescence programme was observed in experimental chronic pancreatitis induced by pancreatic duct ligation or repeated caerulein administration, with the concomitant and differential activation of proliferation and senescence in distinct cell populations. Conclusions Acinar cells dedifferentiate into an embryonic progenitor-like phenotype upon suspension culture. This is associated with the activation of a senescence programme. Both processes take place in experimental chronic pancreatitis where senescence may contribute to limit tumour progression. [ABSTRACT FROM AUTHOR]
- Published
- 2011
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- View/download PDF
248. Recent advances and prospects in the differentiation of pancreatic cells from human embryonic stem cells.
- Author
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Mfopou JK, Chen B, Sui L, Sermon K, Bouwens L, Mfopou, Josué Kunjom, Chen, Bing, Sui, Lina, Sermon, Karen, and Bouwens, Luc
- Abstract
Recent studies with human embryonic stem (hES) cells have established new protocols for substantial generation of pancreatic progenitors from definitive endoderm. These findings add to the efficient derivation of definitive endoderm, which is controlled by Wnt and Nodal pathways, and delineate a step forward in the quest for alternative beta-cell sources. It also indicates that critical refining of the available strategies might help define a universal protocol for pancreatic differentiation applicable to several cell lines, therefore offering the possibility for transplantation of immune-matched or patient-specific hES-derived beta-cells. We appraise here the fundamental role that bone morphogenetic protein, fibroblast growth factor, and retinoid signaling play during pancreas development, and describe a fundamental emergence of their combination in recent studies that generated pancreatic cells from hES cells. We finally enumerate some prospects that might improve further differentiation of the progenitor cells into functional beta-cells needed in diabetes cell therapy. [ABSTRACT FROM AUTHOR]
- Published
- 2010
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- View/download PDF
249. In vitro development of islets from human adult pancreatic tissues
- Author
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Gao, Ru, University of Helsinki, Faculty of Medicine, Haartman Institute, Program of Developmental and Reproductive Biology, Helsingin yliopisto, lääketieteellinen tiedekunta, kliinisteoreettinen laitos, Helsingfors universitet, medicinska fakulteten, Haartman institutet, Bouwens, Luc, and Otonkoski, Timo
- Subjects
lääketiede - Abstract
Transplantation of isolated islets from cadaver pancreas is a promising possibility for the optimal treatment of type 1 diabetes. The lack of islets is a major problem. Here we have investigated the possibility of generating islets in tissue culture of human pancreatic cells. We first reproduced a previously reported method of in vitro generation of endocrine cells from human adult pancreatic tissue. By tracing the bromodeoxyuridine-labeled cells in differentiated islet buds, we found that the pancreatic progenitor cells represented a subpopulation of cytokeratin 19 (CK19)-positive ductal cells. Serum-free medium and Matrigel overlay were essential for the endocrine differentiation. We then examined the involvement of preexisting islet cells in islet neogenesis. About 6-10% of endocrine cells dedifferentiated and acquired a transitional phenotype by coexpressing CK19. Significant cell proliferation was only observed in CK19-positive cells, but not in chromogranin A-positive endocrine cells. The in vitro-derived human islets were morphologically and functionally immature when compared with normal islets. Their insulin mRNA levels were only 4-5% of that found in fresh human islets, and glucose-stimulated insulin release was 3 times lower than that of control islets. Moreover, some immature endocrine cells coexpressed insulin and glucagon. After transplantation in nude mice, the in vitro-generated islets became mature with one type of hormone per endocrine cell. In addition, we also found that also in both fresh islet transplants many cells coexpressed endocrine markers and ductal marker CK19 as a sign of ductal to endocrine cell transition. Finally, we studied the effects of clinically used immunosuppressive drugs on precursor cell proliferation and differentiation. Mycophenolate mofetil (MMF) severely hampered duct-cell proliferation, and significantly reduced the total DNA content indicating its antiproliferative effect on the precursors. Tacrolimus mainly affected differentiated beta cells by decreasing the insulin content per DNA as well as the proportion of insulin-positive cells. Sirolimus and daclizumab did not show any individual or synergistic side effects suggesting that these drugs are amenable for use in clinical islet transplantation. In summary, we confirm the capacity of endocrine differentiation from progenitors present in the adult human pancreas. The plasticity of differentiated cell types of human pancreas may be a potential mechanism of human pancreas regeneration. Ductal cell differentiation into endocrine cells in transplanted islets may be an important factor in sustaining the long-term function of islet transplants. The immunosuppressive protocol is likely to be an important determinant of long-term clinical islet graft function. Moreover, these results provide new information on the mechanisms of pancreatic islet regeneration and provide the basis for the development of new strategies for the treatment of insulin deficient diabetes mellitus. Haiman saarekesolujen siirto on lupaava tyypin 1 diabeteksen hoitomahdollisuus. Tässä väitöskirjatutkimuksessa selvitettiin mahdollisuutta kasvattaa soluviljelmissä uusia insuliinia tuottavia saarekesoluja ihmisen haimasoluista, jotka jäävät yli saarekkeiden eristyksen jälkeen. Tutkimusta varten kehitettiin viljelymenetelmä, jossa jakautuvat solut ovat pääasiassa haiman tiehyiden epiteelisoluja. Sopivissa olosuhteissa nämä solut muodostivat n. 4 viikon viljelyn aikana kystamaisia rakenteita, joiden pinnalta kehittyi uusia endokriinisiä, insuliinia ja glukagonia erittäviä saarekesoluja. Ensimmäisessä osatyössä optimoitiin soluviljelyolosuhteet tätä erilaistumista varten. Toisessa osatyössä tutkittiin tarkemmin niitä tapahtumia, jotka edeltävät endokriinistä erilaistumistapahtumaa viljelmissä. Havaittiin, että erilaistuneilla haimasoluilla on kyky muuttaa merkkiominaisuuksiaan viljelyoloissa. Osa valmiiksi erilaistuneista saarekesoluista alkoi ilmentää tiehytsoluille tyypillisiä merkkiominaisuuksia ja kadottaa samalla endokriinisten solujen ominaisuuksia. Tällöin solut myös pystyivät jakautumaan. Havaittu saarekkeiden uudismuodostus perustui ainakin osittain tällaisiin ilmiöihin, jotka osoittavat että haiman saarekesolujen plastisuus on paljon aiemmin luultua suurempi. Soluviljelyssä tuotetut saarekkeet olivat morfologisesti ja toiminnallisesti epäkypsiä. Kun näitä soluja kolmannessa osatyössä siirrettiin immuunipuutteisiin hiiriin, todettiin niiden kypsyvän ja alkavan muistuttaa normaaleja saarekesoluja. Neljännessa osatyössä tutkittiin kliinisisesti saarekesiirtopotilailla käytettävien immunosuppressiivisten lääkeaineiden vaikutuksia edellä kuvatussa soluviljelymallissa. Havaittiin, että laajasti käytetty lääkeaine, mykofenolaatti, oli voimakkaasti epiteelisolujen jakautumista estävä ja vähensi täten merkittävästi soluviljelmässä syntyvien uusien saarekesolujen määrää. Tämä lääkeaine ei kuitenkaan vaikuttanut negatiivisesti erilaistuneisiin endokriinisiin soluihin, toisin kuin toinen yleisesti käytetty lääke, takrolimuusi. Yhteenvetona, tutkimuksessa pystyttiin osoittamaan kokeellisessa mallissa ihmisen haiman saarekkeiden uudismuodostuminen esiasteisista soluista. Eräitä keskeisiä säätelymekanismeja tunnistettiin. Havainnot viittaavat siihen, että saarekesiirrännäisen pitkäaikainen toimivuus riippuu solujen uusiutumiskyvystä ja hyljinnän estoon käytetyillä lääkkeillä voi olla tässä tärkeä merkitys. Tutkimukset antavat myös uutta tietoa haiman saarekkeiden regeneraatiokyvystä, mikä tarjoaa mahdollisuuksia uusien insuliininpuutosdiabeteksen hoitokeinojen kehittämiselle.
- Published
- 2007
250. Resolution of Acinar Dedifferentiation Regulates Tissue Remodeling in Pancreatic Injury and Cancer Initiation.
- Author
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Baldan J, Camacho-Roda J, Ballester M, Høj K, Kurilla A, Maurer HC, Arcila-Barrera S, Lin X, Pan Z, Castro JL, Mayorca-Guiliani AE, Rift CV, Hasselby J, Bouwens L, Lefebvre V, David CJ, Parnas O, DelGiorno KE, Erler JT, Rooman I, and Arnes L
- Subjects
- Animals, Mice, Humans, Pancreatitis pathology, Pancreatitis genetics, Pancreatitis metabolism, SOXC Transcription Factors genetics, SOXC Transcription Factors metabolism, Disease Models, Animal, Pancreas pathology, Pancreas metabolism, Cell Transformation, Neoplastic pathology, Cell Transformation, Neoplastic genetics, Cell Transformation, Neoplastic metabolism, Gene Expression Regulation, Neoplastic, Gene Expression Profiling, Carcinoma in Situ pathology, Carcinoma in Situ genetics, Carcinoma in Situ metabolism, Transcriptome, Pancreatic Neoplasms pathology, Pancreatic Neoplasms genetics, Pancreatic Neoplasms metabolism, Acinar Cells pathology, Acinar Cells metabolism, Carcinoma, Pancreatic Ductal pathology, Carcinoma, Pancreatic Ductal genetics, Carcinoma, Pancreatic Ductal metabolism, Metaplasia genetics, Metaplasia pathology, Proto-Oncogene Proteins p21(ras) genetics, Proto-Oncogene Proteins p21(ras) metabolism, Cell Dedifferentiation, Ceruletide
- Abstract
Background & Aims: Acinar-to-ductal metaplasia (ADM) is crucial in the development of pancreatic ductal adenocarcinoma. However, our understanding of the induction and resolution of ADM remains limited. We conducted comparative transcriptome analyses to identify conserved mechanisms of ADM in mouse and human., Methods: We identified Sox4 among the top up-regulated genes. We validated the analysis by RNA in situ hybridization. We performed experiments in mice with acinar-specific deletion of Sox4 (Ptf1a: CreER; Rosa26
-LSL-YFPLSL-YFP ; Sox4fl/fl ) with and without an activating mutation in Kras (KrasLSL-G12D/+ ). Mice were given caerulein to induce pancreatitis. We performed phenotypic analysis by immunohistochemistry, tissue decellularization, and single-cell RNA sequencing., Results: We demonstrated that Sox4 is reactivated in ADM and pancreatic intraepithelial neoplasias. Contrary to findings in other tissues, Sox4 actually counteracts cellular dedifferentiation and helps maintain tissue homeostasis. Moreover, our investigations unveiled the indispensable role of Sox4 in the specification of mucin-producing cells and tuft-like cells from acinar cells. We identified Sox4-dependent non-cell-autonomous mechanisms regulating the stromal reaction during disease progression. Notably, Sox4-inferred targets are activated upon KRAS inactivation and tumor regression., Conclusions: Our results indicate that our transcriptome analysis can be used to investigate conserved mechanisms of tissue injury. We demonstrate that Sox4 restrains acinar dedifferentiation and is necessary for the specification of acinar-derived metaplastic cells in pancreatic injury and cancer initiation and is activated upon Kras ablation and tumor regression in mice. By uncovering novel potential strategies to promote tissue homeostasis, our findings offer new avenues for preventing the development of pancreatic ductal adenocarcinoma., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)- Published
- 2024
- Full Text
- View/download PDF
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