| 1. |
- Helker, Christian S M, et al.
(författare)
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A whole organism small molecule screen identifies novel regulators of pancreatic endocrine development.
- 2019
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Ingår i: Development. - : The Company of Biologists. - 0950-1991 .- 1477-9129. ; 146:14
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Tidskriftsartikel (refereegranskat)abstract
- An early step in pancreas development is marked by the expression of the transcription factor Pdx1 within the pancreatic endoderm, where it is required for the specification of all endocrine cell types. Subsequently, Pdx1 expression becomes restricted to the β-cell lineage, where it plays a central role in β-cell function. This pivotal role of Pdx1 at various stages of pancreas development makes it an attractive target to enhance pancreatic β-cell differentiation and increase β-cell function. In this study, we used a newly generated zebrafish reporter to screen over 8000 small molecules for modulators of pdx1 expression. We found four hit compounds and validated their efficacy at different stages of pancreas development. Notably, valproic acid treatment increased pancreatic endoderm formation, while inhibition of TGFβ signaling led to α-cell to β-cell transdifferentiation. HC toxin, another HDAC inhibitor, enhances β-cell function in primary mouse and human islets. Thus, using a whole organism screening strategy, this study identified new pdx1 expression modulators that can be used to influence different steps in pancreas and β-cell development.
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| 2. |
- Jonsson, Alexander, et al.
(författare)
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Protein Kinase R Is Constitutively Expressed in the Human Pancreas
- 2019
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Ingår i: Journal of Histochemistry & Cytochemistry. - : SAGE Publications. - 0022-1554 .- 1551-5044. ; 67:2, s. 99-105
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Tidskriftsartikel (refereegranskat)abstract
- Viral infection of the insulin-producing cells in the pancreas has been proposed in the etiology of type 1 diabetes. Protein kinase R (PKR) is a cytoplasmic protein activated through phosphorylation in response to cellular stress and particularly viral infection. As PKR expression in pancreatic beta-cells has been interpreted as a viral footprint, this cross-sectional study aimed at characterizing the PKR expression in non-diabetic human pancreases. PKR expression was evaluated in pancreas tissue from 16 non-diabetic organ donors, using immunohistochemistry, qPCR, and western blot. Immunohistochemistry and western blot showed readily detectable PKR expression in the pancreatic parenchyma. The qPCR detected PKR mRNA in both endocrine and exocrine samples, with a slightly higher expression in the islets. In conclusion, PKR is constitutively expressed in both endocrine and exocrine parts of the pancreas and its expression should not be interpreted as a viral footprint in pancreatic beta cells.
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| 3. |
- Korsgren, Olle, et al.
(författare)
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Imagining a better future for all people with type 1 diabetes mellitus
- 2019
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Ingår i: Nature Reviews Endocrinology. - : Springer Science and Business Media LLC. - 1759-5029 .- 1759-5037. ; 15:11, s. 623-624
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- For a person with type 1 diabetes mellitus, lifelong insulin treatment is the only therapeutic option. However, increased blood levels of glucose are just a symptom of impaired beta-cell function. Approaching the centenary of the first insulin injection, broadening of international therapeutic guidelines to improve diagnostics, as well as monitor and preserve beta-cell function, is warranted.
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| 4. |
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| 5. |
- Seiron, Peter, et al.
(författare)
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Characterisation of the endocrine pancreas in type 1 diabetes : islet size is maintained but islet number is markedly reduced
- 2019
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Ingår i: The journal of pathology. Clinical research. - : Wiley. - 2056-4538. ; 5:4, s. 248-255
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Tidskriftsartikel (refereegranskat)abstract
- Insulin deficiency in type 1 diabetes (T1D) is generally considered a consequence of immune-mediated specific beta-cell loss. Since healthy pancreatic islets consist of similar to 65% beta cells, this would lead to reduced islet size, while the number of islets per pancreas volume (islet density) would not be affected. In this study, we compared the islet density, size, and size distribution in biopsies from subjects with recent-onset or long-standing T1D, with that in matched non-diabetic subjects. The results presented show preserved islet size and islet size distribution, but a marked reduction in islet density in subjects with recent onset T1D compared with non-diabetic subjects. No further reduction in islet density occurred with increased disease duration. Insulin-negative islets in T1D subjects were dominated by glucagon-positive cells that often had lost the alpha-cell transcription factor ARX while instead expressing PDX1, normally only expressed in beta cells within the islets. Based on our findings, we propose that failure to establish a sufficient islet number to reach the beta-cell mass needed to cope with episodes of increased insulin demand contributes to T1D susceptibility. Exhaustion induced by relative lack of beta cells could then potentially drive beta-cell dedifferentiation to alpha-cells, explaining the preserved islet size observed in T1D compared to controls.
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| 6. |
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| 7. |
- Stenwall, Anton, et al.
(författare)
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Characterization of host defense molecules in the human pancreas
- 2019
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Ingår i: Islets. - : Informa UK Limited. - 1938-2014 .- 1938-2022. ; 11:4, s. 89-101
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Tidskriftsartikel (refereegranskat)abstract
- The gut microbiota can play a role in pancreatitis and, likely, in the development of type 1 diabetes (T1D). Anti-microbial peptides and secretory proteins are important mediators of the innate immune response against bacteria but their expression in the human pancreas is not fully known. In this study, immunohistochemistry was used to analyze the expression of seven anti-microbial peptides (Defensin alpha 1, alpha 4, beta 1-4 and Cathelicidin) and two secretory proteins with known antimicrobial properties (REG3A and GP2) in pancreatic and duodenal biopsies from 10 non-diabetic organ donors and one organ donor that died at onset of T1D. Immunohistochemical data was compared with previously published whole-transcriptome data sets. Seven (Defensin alpha 1, beta 2, beta 3, alpha 4, GP2, Cathelicidin, and REG3A) host defense molecules showed positive staining patterns in most non-diabetic organ donors, whereas two (Defensin beta 1 and beta 4) were negative in all non-diabetic donors. Two molecules (Defensin alpha 1 and GP2) were restricted to the exocrine pancreas whereas two (Defensin beta 3, alpha 4) were only expressed in islet tissue. Cathelicidin, beta 2, and REG3A were expressed in both islets and exocrine tissue. The donor that died at onset of T1D had generally less positivity for the host defense molecules, but, notably, this pancreas was the only one where defensin beta 1 was found. Neither donor age, immune-cell infiltration, nor duodenal expression correlated to the pancreatic expression of host defense molecules. In conclusion, these findings could have important implications for the inflammatory processes in diabetes and pancreatitis as we find several host defense molecules expressed by the pancreatic tissue.
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