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- Jantti, H, et al.
(författare)
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Human PSEN1 Mutant Glia Improve Spatial Learning and Memory in Aged Mice
- 2022
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Ingår i: Cells. - : MDPI AG. - 2073-4409. ; 11:24
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Tidskriftsartikel (refereegranskat)abstract
- The PSEN1 ΔE9 mutation causes a familial form of Alzheimer’s disease (AD) by shifting the processing of amyloid precursor protein (APP) towards the generation of highly amyloidogenic Aβ42 peptide. We have previously shown that the PSEN1 ΔE9 mutation in human-induced pluripotent stem cell (iPSC)-derived astrocytes increases Aβ42 production and impairs cellular responses. Here, we injected PSEN1 ΔE9 mutant astrosphere-derived glial progenitors into newborn mice and investigated mouse behavior at the ages of 8, 12, and 16 months. While we did not find significant behavioral changes in younger mice, spatial learning and memory were paradoxically improved in 16-month-old PSEN1 ΔE9 glia-transplanted male mice as compared to age-matched isogenic control-transplanted animals. Memory improvement was associated with lower levels of soluble, but not insoluble, human Aβ42 in the mouse brain. We also found a decreased engraftment of PSEN1 ΔE9 mutant cells in the cingulate cortex and significant transcriptional changes in both human and mouse genes in the hippocampus, including the extracellular matrix-related genes. Overall, the presence of PSEN1 ΔE9 mutant glia exerted a more beneficial effect on aged mouse brain than the isogenic control human cells likely as a combination of several factors.
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| 3. |
- Kjellman, M., et al.
(författare)
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A Plasma Protein Biomarker Strategy for Detection of Small Intestinal Neuroendocrine Tumors
- 2021
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Ingår i: Neuroendocrinology. - : S. Karger AG. - 0028-3835 .- 1423-0194. ; 111:9, s. 840-849
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Tidskriftsartikel (refereegranskat)abstract
- Background: Small intestinal neuroendocrine tumors (SI-NETs) are difficult to diagnose in the early stage of disease. Current blood biomarkers such as chromogranin A (CgA) and 5-hydroxyindolacetic acid have low sensitivity (SEN) and specificity (SPE). This is a first preplanned interim analysis (Nordic non-interventional, prospective, exploratory, EXPLAIN study [NCT02630654]). Its objective is to investigate if a plasma protein multi-biomarker strategy can improve diagnostic accuracy (ACC) in SI-NETs. Methods: At the time of diagnosis, before any disease-specific treatment was initiated, blood was collected from patients with advanced SI-NETs and 92 putative cancer-related plasma proteins from 135 patients were analyzed and compared with the results of age- and sex-matched controls (n = 143), using multiplex proximity extension assay and machine learning techniques. Results: Using a random forest model including 12 top ranked plasma proteins in patients with SI-NETs, the multi-biomarker strategy showed SEN and SPE of 89 and 91%, respectively, with negative predictive value (NPV) and positive predictive value (PPV) of 90 and 91%, respectively, to identify patients with regional or metastatic disease with an area under the receiver operator characteristic curve (AUROC) of 99%. In 30 patients with normal CgA concentrations, the model provided a diagnostic SPE of 98%, SEN of 56%, and NPV 90%, PPV of 90%, and AUROC 97%, regardless of proton pump inhibitor intake. Conclusion: This interim analysis demonstrates that a multi-biomarker/machine learning strategy improves diagnostic ACC of patients with SI-NET at the time of diagnosis, especially in patients with normal CgA levels. The results indicate that this multi-biomarker strategy can be useful for early detection of SI-NETs at presentation and conceivably detect recurrence after radical primary resection.
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| 4. |
- Krauss, Tobias, et al.
(författare)
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Preventive medicine of von Hippel-Lindau disease-associated pancreatic neuroendocrine tumors
- 2018
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Ingår i: Endocrine-Related Cancer. - : BIOSCIENTIFICA LTD. - 1351-0088 .- 1479-6821. ; 25:9, s. 783-793
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Tidskriftsartikel (refereegranskat)abstract
- Pancreatic neuroendocrine tumors (PanNETs) are rare in von Hippel-Lindau disease (VHL) but cause serious morbidity and mortality. Management guidelines for VHL-PanNETs continue to be based on limited evidence, and survival data to guide surgical management are lacking. We established the European-American-Asian-VHL-PanNET-Registry to assess data for risks for metastases, survival and long-term outcomes to provide best management recommendations. Of 2330 VHL patients, 273 had a total of 484 PanNETs. Median age at diagnosis of PanNET was 35 years (range 10-75). Fifty-five (20%) patients had metastatic PanNETs. Metastatic PanNETs were significantly larger (median size 5 vs 2 cm; P < 0.001) and tumor volume doubling time (TVDT) was faster (22 vs 126 months; P = 0.001). All metastatic tumors were >= 2.8 cm. Codons 161 and 167 were hotspots for VHL germline mutations with enhanced risk for metastatic PanNETs. Multivariate prediction modeling disclosed maximum tumor diameter and TVDT as significant predictors for metastatic disease (positive and negative predictive values of 51% and 100% for diameter cut-off >= 2.8 cm, 44% and 91% for TVDT cut-off of <= 24 months). In 117 of 273 patients, PanNETs > 1.5 cm in diameter were operated. Ten-year survival was significantly longer in operated vs non-operated patients, in particular for PanNETs < 2.8 cm vs >= 2.8 cm (94% vs 85% by 10 years; P = 0.020; 80% vs 50% at 10 years; P = 0.030). This study demonstrates that patients with PanNET approaching the cut-off diameter of 2.8 cm should be operated. Mutations in exon 3, especially of codons 161/167 are at enhanced risk for metastatic PanNETs. Survival is significantly longer in operated non-metastatic VHL-PanNETs.
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| 7. |
- Makitie, R. E., et al.
(författare)
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An ARHGAP25 variant links aberrant Rac1 function to early-onset skeletal fragility
- 2021
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Ingår i: JBMR Plus. - : Wiley. - 2473-4039. ; 5:7
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Tidskriftsartikel (refereegranskat)abstract
- Ras homologous guanosine triphosphatases (RhoGTPases) control several cellular functions, including cytoskeletal actin remodeling and cell migration. Their activities are downregulated by GTPase-activating proteins (GAPs). Although RhoGTPases are implicated in bone remodeling and osteoclast and osteoblast function, their significance in human bone health and disease remains elusive. Here, we report defective RhoGTPase regulation as a cause of severe, early-onset, autosomal-dominant skeletal fragility in a three-generation Finnish family. Affected individuals (n = 13) presented with multiple low-energy peripheral and vertebral fractures despite normal bone mineral density (BMD). Bone histomorphometry suggested reduced bone volume, low surface area covered by osteoblasts and osteoclasts, and low bone turnover. Exome sequencing identified a novel heterozygous missense variant c.652G>A (p.G218R) in ARHGAP25, encoding a GAP for Rho-family GTPase Rac1. Variants in the ARHGAP25 5 ' untranslated region (UTR) also associated with BMD and fracture risk in the general population, across multiple genomewide association study (GWAS) meta-analyses (lead variant rs10048745). ARHGAP25 messenger RNA (mRNA) was expressed in macrophage colony-stimulating factor (M-CSF)-stimulated human monocytes and mouse osteoblasts, indicating a possible role for ARHGAP25 in osteoclast and osteoblast differentiation and activity. Studies on subject-derived osteoclasts from peripheral blood mononuclear cells did not reveal robust defects in mature osteoclast formation or resorptive activity. However, analysis of osteosarcoma cells overexpressing the ARHGAP25 G218R-mutant, combined with structural modeling, confirmed that the mutant protein had decreased GAP-activity against Rac1, resulting in elevated Rac1 activity, increased cell spreading, and membrane ruffling. Our findings indicate that mutated ARHGAP25 causes aberrant Rac1 function and consequently abnormal bone metabolism, highlighting the importance of RhoGAP signaling in bone metabolism in familial forms of skeletal fragility and in the general population, and expanding our understanding of the molecular pathways underlying skeletal fragility. (c) 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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| 12. |
- Casar Borota, Olivera, et al.
(författare)
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Corticotroph Aggressive Pituitary Tumors and Carcinomas Frequently Harbor ATRX Mutations
- 2021
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Ingår i: Journal of Clinical Endocrinology & Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 106:4, s. 1183-1194
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Tidskriftsartikel (refereegranskat)abstract
- Context: Aggressive pituitary tumors (APTs) are characterized by unusually rapid growth and lack of response to standard treatment. About 1% to 2% develop metastases being classified as pituitary carcinomas (PCs). For unknown reasons, the corticotroph tumors are overrepresented among APTs and PCs. Mutations in the alpha thalassemia/mental retardation syndrome X-linked (ATRX) gene, regulating chromatin remodeling and telomere maintenance, have been implicated in the development of several cancer types, including neuroendocrine tumors. Objective: To study ATRX protein expression and mutational status of the ATRX gene in APTs and PCs. Design: We investigated ATRX protein expression by using immunohistochemistry in 30 APTs and 18 PCs, mostly of Pit-1 and T-Pit cell lineage. In tumors lacking ATRX immunolabeling, mutational status of the ATRX gene was explored. Results: Nine of the 48 tumors (19%) demonstrated lack of ATRX immunolabelling with a higher proportion in patients with PCs (5/18; 28%) than in those with APTs (4/30;13%). Lack of ATRX was most common in the corticotroph tumors, 7/22 (32%), versus tumors of the Pit-1 lineage, 2/24 (8%). Loss-of-function ATRX mutations were found in all 9 ATRX immunonegative cases: nonsense mutations (n = 4), frameshift deletions (n = 4), and large deletions affecting 22-28 of the 36 exons (n = 3). More than 1 ATRX gene defect was identified in 2 PCs. Conclusion: ATRX mutations occur in a subset of APTs and are more common in corticotroph tumors. The findings provide a rationale for performing ATRX immunohistochemistry to identify patients at risk of developing aggressive and potentially metastatic pituitary tumors.
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| 17. |
- Makitie, R. E., et al.
(författare)
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Skeletal Characteristics of WNT1 Osteoporosis in Children and Young Adults
- 2016
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Ingår i: Journal of Bone and Mineral Research. - : Wiley. - 0884-0431 .- 1523-4681. ; 31:9, s. 1734-1742
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Tidskriftsartikel (refereegranskat)abstract
- WNT proteins comprise a 19-member glycoprotein family that act in several developmental and regenerative processes. In bone, WNT proteins regulate osteoblast differentiation and maintain bone health by activating the canonical WNT/-catenin pathway. We reported a heterozygous missense mutation c.652T>G (p.C218G) in WNT1 exon 4 as the cause for severe early-onset, autosomal dominant osteoporosis. The initial study concerned a large Finnish family with 10 affected adults. Here we report clinical findings of the WNT1 osteoporosis in 8 children and young adults (median age 14 years; range 10 to 30 years) in two families, all with the p.C218G mutation in WNT1. Clinical assessments showed no apparent dysmorphia or features similar to typical osteogenesis imperfecta (OI). Biochemistry revealed no changes in parameters of calcium metabolism and bone turnover markers. Fracture frequencies varied, but all subjects had sustained at least one fracture and 4 had a pathological fracture history. Plain radiographs showed osteopenic appearance, loss in vertebral height, and thin diaphyses of the long bones. Bone densitometry showed the BMD to be below normal median in all subjects and the bone mass deficit seemed to be more severe in older participants. Bone histomorphometry revealed a low turnover osteoporosis in 2 subjects at ages 14 and 16 years. These findings are congruent with earlier findings in adult patients and indicate that WNT1 osteoporosis causes significant skeletal changes already in early childhood and impairs bone mass gain during pubertal years. Genetic testing of children or close relatives of affected individuals is recommended for appropriate preventive measures. (c) 2016 American Society for Bone and Mineral Research.
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| 18. |
- Nevalainen, H., et al.
(författare)
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Firing of coal and biomass and their mixtures in 50 kW and 12 MW circulating fluidized beds - Phenomenon study and comparison of scales
- 2007
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Ingår i: Fuel. - : Elsevier BV. - 0016-2361. ; 86:14, s. 2043-2051
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Tidskriftsartikel (refereegranskat)abstract
- The combustion dynamics of coal, wood chips and their mixture is investigated. Load change capability and the effect of the individual control variables, for example the mixture ratio of different fuels, on pilot-scale CFB boiler dynamics were also studied. Disturbances in fuel feeding cause fluctuations in the flue gas concentrations. Changes in the heating value are possible due to varying moisture content of the fuel. Both these disturbances affect the instantaneous firing rate in a boiler. Also the characteristics of the fuels have to be taken into consideration when designing boiler control systems. When co-firing two fuels with clearly distinct combustion characteristics, direct assumptions based on each fuel's characteristies cannot be made about combustion behaviour of their mixture. Combustion experiments with coal and wood chips and their co-firing were carried out in a pilot-scale CFB reactor (VTT) and a large-scale CFB boiler (Chalmers). A comparison of the combustion in the two different size reactors, provides information about scaling. The combustion responses due to changes in the fuel feeding of the two circulating fluidized beds are analyzed by a dynamic model. (c) 2007 Elsevier Ltd. All rights reserved.
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