| 11. |
- Delgado-Vega, Angelica, et al.
(författare)
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Recent findings on genetics of systemic autoimmune diseases
- 2010
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Ingår i: Current Opinion in Immunology. - : Elsevier BV. - 0952-7915 .- 1879-0372. ; 22:6, s. 698-705
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Forskningsöversikt (refereegranskat)abstract
- Association studies of over 1 million SNPs capturing most of the human genome common variation became possible thanks to the information provided by the HapMap International project and the development of high-throughput genotyping technologies at accessible prices. Genome-wide scans analyzing thousands of individuals have now identified most if not all of the major genes involved in susceptibility for several systemic autoimmune diseases. In particular, results for rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and systemic sclerosis (SSc) are reviewed here. While most genes are shared between diseases, few seem to be unique reflecting that we still are long before knowing all genes, their interactions with other genes and the environment and their impact on biological functions.
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| 12. |
- Deng, Wu-Min, et al.
(författare)
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Dystroglycan is required for polarizing the epithelial cells and the oocyte in Drosophila.
- 2003
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Ingår i: Development: For advances in developmental biology and stem cells. - 1477-9129. ; 130:1, s. 173-184
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Tidskriftsartikel (refereegranskat)abstract
- The transmembrane protein Dystroglycan is a central element of the dystrophin-associated glycoprotein complex, which is involved in the pathogenesis of many forms of muscular dystrophy. Dystroglycan is a receptor for multiple extracellular matrix (ECM) molecules such as Laminin, agrin and perlecan, and plays a role in linking the ECM to the actin cytoskeleton; however, how these interactions are regulated and their basic cellular functions are poorly understood. Using mosaic analysis and RNAi in the model organism Drosophila melanogaster, we show that Dystroglycan is required cell-autonomously for cellular polarity in two different cell types, the epithelial cells (apicobasal polarity) and the oocyte (anteroposterior polarity). Loss of Dystroglycan function in follicle and disc epithelia results in expansion of apical markers to the basal side of cells and overexpression results in a reduced apical localization of these same markers. In Dystroglycan germline clones early oocyte polarity markers fail to be localized to the posterior, and oocyte cortical F-actin organization is abnormal. Dystroglycan is also required non-cell-autonomously to organize the planar polarity of basal actin in follicle cells, possibly by organizing the Laminin ECM. These data suggest that the primary function of Dystroglycan in oogenesis is to organize cellular polarity; and this study sets the stage for analyzing the Dystroglycan complex by using the power of Drosophila molecular genetics.
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| 13. |
- Diamanti, Klev, 1987-, et al.
(författare)
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Organ-specific metabolic pathways distinguish prediabetes, type 2 diabetes, and normal tissues
- 2022
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Ingår i: Cell Reports Medicine. - : Elsevier BV. - 2666-3791. ; 3:10
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Tidskriftsartikel (refereegranskat)abstract
- Environmental and genetic factors cause defects in pancreatic islets driving type 2 diabetes (T2D) together with the progression of multi-tissue insulin resistance. Mass spectrometry proteomics on samples from five key metabolic tissues of a cross-sectional cohort of 43 multi-organ donors provides deep coverage of their proteomes. Enrichment analysis of Gene Ontology terms provides a tissue-specific map of altered biological processes across healthy, prediabetes (PD), and T2D subjects. We find widespread alterations in several relevant biological pathways, including increase in hemostasis in pancreatic islets of PD, increase in the complement cascade in liver and pancreatic islets of PD, and elevation in cholesterol biosynthesis in liver of T2D. Our findings point to inflammatory, immune, and vascular alterations in pancreatic islets in PD that are hypotheses to be tested for potential contributions to hormonal perturbations such as impaired insulin and increased glucagon production. This multi-tissue proteomic map suggests tissue-specific metabolic dysregulations in T2D. © 2022 The Author(s)
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| 14. |
- Diaz-Barreiro, A., et al.
(författare)
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The SLE variant Ala71Thr of BLK severely decreases protein abundance and binding to BANK1 through impairment of the SH3 domain function
- 2016
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Ingår i: Genes and Immunity. - : Springer Science and Business Media LLC. - 1466-4879 .- 1476-5470. ; 17:2, s. 128-138
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Tidskriftsartikel (refereegranskat)abstract
- The B-lymphocyte kinase (BLK) gene is associated genetically with several human autoimmune diseases including systemic lupus erythematosus. We recently described that the genetic risk is given by two haplotypes: one covering several strongly linked single-nucleotide polymorphisms within the promoter of the gene that correlated with low transcript levels, and a second haplotype that includes a rare nonsynonymous variant (Ala71Thr). Here we show that this variant, located within the BLK SH3 domain, is a major determinant of protein levels. In vitro analyses show that the 71Thr isoform is hyperphosphorylated and promotes kinase activation. As a consequence, BLK is ubiquitinated, its proteasomal degradation enhanced and the average life of the protein is reduced by half. Altogether, these findings suggest that an intrinsic autoregulatory mechanism previously unappreciated in BLK is disrupted by the 71Thr substitution. Because the SH3 domain is also involved in protein interactions, we sought for differences between the two isoforms in trafficking and binding to protein partners. We found that binding of the 71Thr variant to the adaptor protein BANK1 is severely reduced. Our study provides new insights on the intrinsic regulation of BLK activation and highlights the dominant role of its SH3 domain in BANK1 binding.
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| 15. |
- Fatima, Ambrin, et al.
(författare)
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Monoallelic and bi-allelic variants in NCDN cause neurodevelopmental delay, intellectual disability, and epilepsy
- 2021
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Ingår i: American Journal of Human Genetics. - : Cell Press. - 0002-9297 .- 1537-6605. ; 108:4, s. 739-748
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Tidskriftsartikel (refereegranskat)abstract
- Neurochondrin (NCDN) is a cytoplasmatic neural protein of importance for neural growth, glutamate receptor (mGluR) signaling, and synaptic plasticity. Conditional loss of Ncdn in mice neural tissue causes depressive-like behaviors, impaired spatial learning, and epileptic seizures. We report on NCDN missense variants in six affected individuals with variable degrees of developmental delay, intellectual disability (ID), and seizures. Three siblings were found homozygous for a NCDN missense variant, whereas another three unrelated individuals carried different de novo missense variants in NCDN. We assayed the missense variants for their capability to rescue impaired neurite formation in human neuroblastoma (SH-SY5Y) cells depleted of NCDN. Overexpression of wild-type NCDN rescued the neurite-phenotype in contrast to expression of NCDN containing the variants of affected individuals. Two missense variants, associated with severe neurodevelopmental features and epilepsy, were unable to restore mGluR5-induced ERK phosphorylation. Electrophysiological analysis of SH-SY5Y cells depleted of NCDN exhibited altered membrane potential and impaired action potentials at repolarization, suggesting NCDN to be required for normal biophysical properties. Using available transcriptome data from human fetal cortex, we show that NCDN is highly expressed in maturing excitatory neurons. In combination, our data provide evidence that bi-allelic and de novo variants in NCDN cause a clinically variable form of neurodevelopmental delay and epilepsy, highlighting a critical role for NCDN in human brain development.
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| 16. |
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| 17. |
- Kamble, Prasad G., et al.
(författare)
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Proof-of-concept for CRISPR/Cas9 gene editing in human preadipocytes : Deletion of FKBP5 and PPARG and effects on adipocyte differentiation and metabolism
- 2020
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- CRISPR/Cas9 has revolutionized the genome-editing field. So far, successful application in human adipose tissue has not been convincingly shown. We present a method for gene knockout using electroporation in preadipocytes from human adipose tissue that achieved at least 90% efficiency without any need for selection of edited cells or clonal isolation. We knocked out the FKBP5 and PPARG genes in preadipocytes and studied the resulting phenotypes. PPARG knockout prevented differentiation into adipocytes. Conversely, deletion of FKBP51, the protein coded by the FKBP5 gene, did not affect adipogenesis. Instead, it markedly modulated glucocorticoid effects on adipocyte glucose metabolism and, furthermore, we show some evidence of altered transcriptional activity of glucocorticoid receptors. This has potential implications for the development of insulin resistance and type 2 diabetes. The reported method is simple, easy to adapt, and enables the use of human primary preadipocytes instead of animal adipose cell models to assess the role of key genes and their products in adipose tissue development, metabolism and pathobiology.
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| 18. |
- Kamble, Prasad G., et al.
(författare)
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Role of peroxisome proliferator-activated receptor gamma Pro12Ala polymorphism in human adipose tissue : assessment of adipogenesis and adipocyte glucose and lipid turnover.
- 2018
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Ingår i: Adipocyte. - : Informa UK Limited. - 2162-3945 .- 2162-397X. ; 7:4, s. 285-296
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Tidskriftsartikel (refereegranskat)abstract
- Protective mechanisms of peroxisome proliferator-activated receptor gamma (PPARγ) Pro12Ala polymorphism in type 2 diabetes (T2D) are unclear. We obtained adipose tissue (AT) before and 3 h after oral glucose (OGTT) in carriers and non-carriers of the Ala allele (12 Pro/Pro, 15 Pro/Ala, and 13 Ala/Ala). Adipogenesis, adipocyte glucose uptake and lipolysis as well as PPARγ target genes expression were investigated and compared between the genotype groups. On fasting and post-OGTT, neither basal nor insulin-stimulated adipocyte glucose uptake differed between genotypes. Compared to fasting, a decreased hormone-sensitive lipase gene expression in Pro/Pro (p<0.05) also accompanied with a higher antilipolytic effect of insulin post-OGTT (p<0.01). The adipocyte size was similar across groups. Preadipocyte differentiation rates between Pro/Pro and Ala/Ala were unchanged. In conclusion, no major differences in AT differentiation, glucose uptake, lipolysis or expression of PPARγ target genes were observed between different PPARγ Pro12Ala genotypes. Albeit small, our study may suggest that other pathways in AT or effects exerted in other tissues might contribute to the Pro12Ala-mediated protection against T2D.
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| 19. |
- Kolliopoulos, Constantinos, et al.
(författare)
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CD44 Depletion in Glioblastoma Cells Suppresses Growth and Stemness and Induces Senescence
- 2022
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Ingår i: Cancers. - : MDPI AG. - 2072-6694. ; 14:15
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Tidskriftsartikel (refereegranskat)abstract
- Simple Summary The hyaluronan receptor CD44 has an important role in glioblastoma multiforme (GBM) progression, but the precise mechanisms have not been elucidated. We have analyzed U251MG glioma cells, expressing CD44 or not, and grown in stem cell-like enriched spheres. Our results revealed that CD44 is important for cell growth and stemness, and for the prevention of senescence. Analysis by RNA sequencing revealed that CD44 is important for the interaction with the hyaluronan-enriched microenvironment. In addition, CD44 depletion impairs certain gene signatures, such as those for platelet-derived growth factor (PDGF) isoforms and PDGF receptors, as well as signatures related to hypoxia, glycolysis, and anti-tumor immune responses. Glioblastoma multiforme (GBM) is a lethal brain tumor, characterized by enhanced proliferation and invasion, as well as increased vascularization and chemoresistance. The expression of the hyaluronan receptor CD44 has been shown to correlate with GBM progression and poor prognosis. Here, we sought to elucidate the molecular mechanisms by which CD44 promotes GBM progression by knocking out (KO) CD44, employing CRISPR/Cas9 gene editing in U251MG cells. CD44-depleted cells exhibited an impaired proliferation rate, as shown by the decreased cell numbers, decreased Ki67-positive cell nuclei, diminished phosphorylation of CREB, and increased levels of the cell cycle inhibitor p16 compared to control cells. Furthermore, the CD44 KO cells showed decreased stemness and increased senescence, which was manifested upon serum deprivation. In stem cell-like enriched spheres, RNA-sequencing analysis of U251MG cells revealed a CD44 dependence for gene signatures related to hypoxia, the glycolytic pathway, and G2 to M phase transition. Partially similar results were obtained when cells were treated with the gamma-secretase inhibitor DAPT, which inhibits CD44 cleavage and therefore inhibits the release of the intracellular domain (ICD) of CD44, suggesting that certain transcriptional responses are dependent on CD44-ICD. Interestingly, the expression of molecules involved in hyaluronan synthesis, degradation, and interacting matrix proteins, as well as of platelet-derived growth factor (PDGF) isoforms and PDGF receptors, were also deregulated in CD44 KO cells. These results were confirmed by the knockdown of CD44 in another GBM cell line, U2990. Notably, downregulation of hyaluronan synthase 2 (HAS2) impaired the hypoxia-related genes and decreased the CD44 protein levels, suggesting a CD44/hyaluronan feedback circuit contributing to GBM progression.
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| 20. |
- Kolliopoulos, Konstantinos, 1986-, et al.
(författare)
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Effect of CD44 on glioma cell progression, invasion and senescence
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Glioblastoma multiforme (GBM) is a lethal brain tumor, characterized by enhanced proliferation rate, increased invasive capacity, and chemoresistance. The expression of the hyaluronan receptor CD44 correlates with GBM progression and poor prognosis. We have initiated studies to elucidate the molecular mechanisms behind the effects of CD44 on tumorigenesis by knocking out (KO) CD44, via employing CRISPR/Cas9 gene editing in U251MG cells. CD44-depleted cells exhibited impaired proliferation rate, as confirmed by decreased cell numbers, Ki67 positive nuclei, diminished p-CREB levels, and increased levels of the cell cycle inhibitor p16 compared to control cells. Furthermore, the CD44 KO cells acquired a pro-senescence state, which was manifested upon serum deprivation. Interestingly, CD44 KO cells showed enhanced migratory and invasive properties, as observed in 2D wound healing and 3D collagen assays, which may be partially attributed to the acquisition of a senescence-associated secretory phenotype (SASP) and activation of the ERK1/2 MAPK pathway. RNA-sequencing analysis of stem-like U251MG cells, grown in spheres, unveiled a CD44-dependency for expression of molecules involved in hyaluronan synthesis and degradation, and of members of the PDGF and PDGF receptor families. These observations highlight the importance of CD44 on GBM progression.
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