1. |
- Gisladottir, Rosa S, et al.
(author)
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Sequence Variants in TAAR5 and Other Loci Affect Human Odor Perception and Naming.
- 2020
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In: Current biology : CB. - : Elsevier BV. - 1879-0445 .- 0960-9822. ; 30:23
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Journal article (peer-reviewed)abstract
- Olfactory receptor (OR) genes in humans form a special class characterized by unusually high DNA sequence diversity, which should give rise to differences in perception and behavior. In the largest genome-wide association study to date based on olfactory testing, we investigated odor perception and naming with smell tasks performed by 9,122 Icelanders, with replication in a separate sample of 2,204 individuals. We discovered an association between a low-frequency missense variant in TAAR5 and reduced intensity rating of fish odor containing trimethylamine (p.Ser95Pro, pcombined= 5.6× 10-15). We demonstrate that TAAR5 genotype affects aversion to fish odor, reflected by linguistic descriptions of the odor and pleasantness ratings. We also discovered common sequence variants in two canonical olfactory receptor loci that associate with increased intensity and naming of licorice odor (trans-anethole: lead variant p.Lys233Asn in OR6C70, pcombined= 8.8× 10-16 and pcombined= 1.4× 10-9) and enhanced naming of cinnamon (trans-cinnamaldehyde; intergenic variant rs317787-T, pcombined= 5.0× 10-17). Together, our results show that TAAR5 genotype variation influences human odor responses and highlight that sequence diversity in canonical OR genes can lead to enhanced olfactory ability, in contrast to the view that greater tolerance for mutations in the human OR repertoire leads to diminished function.
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2. |
- Jonsson, Stefan, et al.
(author)
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Identification of sequence variants influencing immunoglobulin levels
- 2017
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In: Nature Genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 49:8, s. 1182-1191
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Journal article (peer-reviewed)abstract
- Immunoglobulins are the effector molecules of the adaptive humoral immune system. In a genome-wide association study of 19,219 individuals, we found 38 new variants and replicated 5 known variants associating with IgA, IgG or IgM levels or with composite immunoglobulin traits, accounted for by 32 loci. Variants at these loci also affect the risk of autoimmune diseases and blood malignancies and influence blood cell development. Notable associations include a rare variant at RUNX3 decreasing IgA levels by shifting isoform proportions (rs188468174[C>T]: P = 8.3 × 10(-55), β = -0.90 s.d.), a rare in-frame deletion in FCGR2B abolishing IgG binding to the encoded receptor (p.Asn106del: P = 4.2 × 10(-8), β = 1.03 s.d.), four IGH locus variants influencing class switching, and ten new associations with the HLA region. Our results provide new insight into the regulation of humoral immunity.
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3. |
- Nethander, Maria, 1980, et al.
(author)
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An atlas of genetic determinants of forearm fracture.
- 2023
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In: Nature genetics. - : Springer Nature. - 1546-1718 .- 1061-4036. ; 55:11, s. 1820-1830
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Journal article (peer-reviewed)abstract
- Osteoporotic fracture is among the most common and costly of diseases. While reasonably heritable, its genetic determinants have remained elusive. Forearm fractures are the most common clinically recognized osteoporotic fractures with a relatively high heritability. To establish an atlas of the genetic determinants of forearm fractures, we performed genome-wide association analyses including 100,026 forearm fracture cases. We identified 43 loci, including 26 new fracture loci. Although most fracture loci associated with bone mineral density, we also identified loci that primarily regulate bone quality parameters. Functional studies of one such locus, at TAC4, revealed that Tac4-/- mice have reduced mechanical bone strength. The strongest forearm fracture signal, at WNT16, displayed remarkable bone-site-specificity with no association with hip fractures. Tall stature and low body mass index were identified as new causal risk factors for fractures. The insights from this atlas may improve fracture prediction and enable therapeutic development to prevent fractures.
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4. |
- Nishibori, Yukino, et al.
(author)
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Glcci1 Deficiency Leads to Proteinuria
- 2011
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In: Journal of the American Society of Nephrology. - 1046-6673 .- 1533-3450. ; 22:11, s. 2037-2046
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Journal article (peer-reviewed)abstract
- Unbiased transcriptome profiling and functional genomics approaches identified glucocorticoid-induced transcript 1 (GLCCI1) as being a transcript highly specific for the glomerulus, but its role in glomerular development and disease is unknown. Here, we report that mouse glomeruli express far greater amounts of Glcci1 protein compared with the rest of the kidney. RT-PCR and Western blotting demonstrated that mouse glomerular Glcci1 is approximately 60 kD and localizes to the cytoplasm of podocytes in mature glomeruli. In the fetal kidney, intense Glcci1 expression occurs at the capillary-loop stage of glomerular development. Using gene knockdown in zebrafish with morpholinos, morphants lacking Glcci1 function had collapsed glomeruli with foot-process effacement. Permeability studies of the glomerular filtration barrier in these zebrafish morphants demonstrated a disruption of the selective glomerular permeability filter. Taken together, these data suggest that Glcci1 promotes the normal development and maintenance of podocyte structure and function.
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5. |
- Oddsson, Ásmundur
(author)
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Characterization of novel genes of importance for renal glomerular function and disease
- 2013
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Doctoral thesis (other academic/artistic)abstract
- Glomerular kidney diseases are a major health care burden. The glomerular filtration barrier consists of three layers: the slit diaphragm that bridges the interlocking foot pro- cesses of the podocytes, the glomerular basement membrane and fenestrated endothelial cells. The filtration barrier is permselective to plasma macromolecules based on size, shape, and charge. The molecular makeup of the filtration barrier determines its permselectivity. Knowledge about the molecular mechanisms of the glomerular filtration barrier has been gained with the study of genes mutated in humans and animal models of glomerular kidney disease. In the thesis work, we performed a proteome analysis of healthy glomeruli in mice using two-dimensional gel electrophoresis coupled to mass spectrometry. A total of 232 unique proteins were identified from 414 gel spots. This study provided a snapshot of the glomerular proteome that can serve as reference for future glomerular protein biomarker studies. We describe the expression and physiological function of the gene Glcci1 in zebrafish. His- tological analysis of Glcci1 showed expression in podocytes and mesangial cells. In vivo and in vitro studies demonstrated that Glcci1 expression is induced by glucocorticoids. Depletion of Glcci1 by morpholino knockdown resulted in the development of pericardial edema and defects in glomerular filtration. Our results suggest a role for Glcci1 in glomerular injury and proteinuria. Knockdown experiments of the paralogs Plekhh1 and Plekhh2 in zebrafish resulted in gross morphological changes in the glomerulus, including thickening of the glomerular basement membrane and disorganization of the podocyte foot processes associated with a defective filtration barrier. These results suggest a role for Plekhh1 and Plekhh2 in regulating podocyte foot process morphology in zebrafish. We further characterized Plekhh1 and Plekhh2 in knockout mouse models. Single knockouts of Plekhh1 and Plekhh2 do not develop any apparent phenotype. Plekhh1 and Plekhh2 deficient mice were intercrossed to produce mice lacking both genes. This yielded fewer than expected number of double knockout offspring, suggesting functional redundancy. Ultrastructural analysis of surviving double knockout mice did not reveal changes in glomerular morphology suggesting that Plekhh1 and Plekhh2 are largely redundant for kidney function in mice. These results give insight into glomerular biology and pathomechanisms of kidney disease that might provide a basis for translational research in the future.
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6. |
- Oddsson, Asmundur, et al.
(author)
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Deficit of homozygosity among 1.52 million individuals and genetic causes of recessive lethality
- 2023
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In: Nature Communications. - : Springer Nature. - 2041-1723. ; 14:1
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Journal article (peer-reviewed)abstract
- Genotypes causing pregnancy loss and perinatal mortality are depleted among living individuals and are therefore difficult to find. To explore genetic causes of recessive lethality, we searched for sequence variants with deficit of homozygosity among 1.52 million individuals from six European populations. In this study, we identified 25 genes harboring protein-altering sequence variants with a strong deficit of homozygosity (10% or less of predicted homozygotes). Sequence variants in 12 of the genes cause Mendelian disease under a recessive mode of inheritance, two under a dominant mode, but variants in the remaining 11 have not been reported to cause disease. Sequence variants with a strong deficit of homozygosity are over-represented among genes essential for growth of human cell lines and genes orthologous to mouse genes known to affect viability. The function of these genes gives insight into the genetics of intrauterine lethality. We also identified 1077 genes with homozygous predicted loss-of-function genotypes not previously described, bringing the total set of genes completely knocked out in humans to 4785.
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7. |
- Patrakka, Jaakko, et al.
(author)
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Expression and subcellular distribution of novel glomerulus-associated proteins dendrin, ehd3, sh2d4a, plekhh2, and 2310066E14Rik
- 2007
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In: Journal of the American Society of Nephrology. - : Ovid Technologies (Wolters Kluwer Health). - 1046-6673 .- 1533-3450. ; 18:3, s. 689-697
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Journal article (peer-reviewed)abstract
- The glomerular capillary tuft is a highly specialized microcapillary that is dedicated to function as a sophisticated molecular sieve. The glomerulus filter has a unique molecular composition, and several essential glomerular proteins are expressed in the kidney exclusively by glomerular podocytes. A catalog of > 300 glomerulus-upregulated transcripts that were identified using expressed sequence tag profiling and microarray analysis was published recently. This study characterized the expression profile of five glomerulus-upregulated transcripts/proteins (ehd3, dendrin, sh2d4a, plekhh2, and 2310066E14Rik) in detail. The expression pattern of these novel glomerular transcripts in various mouse tissues was studied using reverse transcriptase-PCR, Northern blotting, and in situ hybridization. For studying the distribution of corresponding proteins, polyclonal antibodies were raised against the gene products, and Western blotting, immunofluorescence, and immunoelectron microscopic analyses were performed. Remarkably, it was discovered that all five transcripts/proteins were expressed in the kidney exclusively by glomerular cells. Ehd3 was expressed only by glomerular endothelial cells. Importantly, ehd3 is the first gene ever shown to be expressed exclusively by glomerular endothelial cells and not by other endothelial cells in the kidney. Dendrin, sh2d4a, plekhh2, and 2310066E14Rik, however, were transcribed solely by podocytes. With the use of polyclonal antibodies, dendrin, sh2d4a, and plekhh2 proteins were localized to the slit diaphragm and the foot process, whereas 2310066E14Rik protein was localized to the podocyte major processes and cell body. This study provides fresh insights into glomerular biology and uncovers new possibilities to explore the role of these novel proteins in the glomerular physiology and pathology.
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8. |
- Rodriguez, Patricia Q., et al.
(author)
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Knockdown of Tmem234 in zebrafish results in proteinuria
- 2015
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In: AMERICAN JOURNAL OF PHYSIOLOGY-RENAL PHYSIOLOGY. - : American Physiological Society. - 1931-857X .- 1522-1466. ; 309:11, s. F955-F966
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Journal article (peer-reviewed)abstract
- Podocytes are highly specialized epithelial cells located at the outer aspects of the glomerular capillary tuft and critical components of the kidney filtration barrier. To maintain their unique features, podocytes express a number of proteins that are only sparsely found elsewhere in the body. In this study, we have identified four (Tmem234, Znf185, Lrrc49, and Slfn5) new highly podocyte-enriched proteins. The proteins are strongly expressed by podocytes, while other parts of the kidney show only weak or no expression. Tmem234, Slfn5, and Lrrc49 are located in foot processes, whereas Znf185 is found in both foot and major processes. Expressional studies in developing kidneys show that these proteins are first expressed at the capillary stage glomerulus, the same stage when the formation of major and foot processes begins. We identified zebrafish orthologs for Tmem234 and Znf185 genes and knocked down their expression using morpholino technology. Studies in zebrafish larvae indicate that Tmem234 is essential for the organization and functional integrity of the pronephric glomerulus filtration barrier, as inactivation of Tmem234 expression results in foot process effacement and proteinuria. In summary, we have identified four novel highly podocyte - enriched proteins and show that one of them, Tmem234, is essential for the normal filtration barrier in the zebrafish pronephric glomerulus. Identification of new molecular components of the kidney filtration barrier opens up possibilities to study their role in glomerulus biology and diseases.
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10. |
- Uglebjerg, Nicoline, et al.
(author)
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Four missense genetic variants in CUBN are associated with higher levels of eGFR in non-diabetes but not in diabetes mellitus or its subtypes : A genetic association study in Europeans
- 2023
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In: Frontiers in Endocrinology. - : Frontiers Media SA. - 1664-2392. ; 14
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Journal article (peer-reviewed)abstract
- Aim: Rare genetic variants in the CUBN gene encoding the main albumin-transporter in the proximal tubule of the kidneys have previously been associated with microalbuminuria and higher urine albumin levels, also in diabetes. Sequencing studies in isolated proteinuria suggest that these variants might not affect kidney function, despite proteinuria. However, the relation of these CUBN missense variants to the estimated glomerular filtration rate (eGFR) is largely unexplored. We hereby broadly examine the associations between four CUBN missense variants and eGFRcreatinine in Europeans with Type 1 (T1D) and Type 2 Diabetes (T2D). Furthermore, we sought to deepen our understanding of these variants in a range of single- and aggregate- variant analyses of other kidney-related traits in individuals with and without diabetes mellitus. Methods: We carried out a genetic association-based linear regression analysis between four CUBN missense variants (rs141640975, rs144360241, rs45551835, rs1801239) and eGFRcreatinine (ml/min/1.73 m2, CKD-EPIcreatinine(2012), natural log-transformed) in populations with T1D (n ~ 3,588) or T2D (n ~ 31,155) from multiple European studies and in individuals without diabetes from UK Biobank (UKBB, n ~ 370,061) with replication in deCODE (n = 127,090). Summary results of the diabetes-group were meta-analyzed using the fixed-effect inverse-variance method. Results: Albeit we did not observe associations between eGFRcreatinine and CUBN in the diabetes-group, we found significant positive associations between the minor alleles of all four variants and eGFRcreatinine in the UKBB individuals without diabetes with rs141640975 being the strongest (Effect=0.02, PeGFR_creatinine=2.2 × 10-9). We replicated the findings for rs141640975 in the Icelandic non-diabetes population (Effect=0.026, PeGFR_creatinine=7.7 × 10-4). For rs141640975, the eGFRcreatinine-association showed significant interaction with albuminuria levels (normo-, micro-, and macroalbuminuria; p = 0.03). An aggregated genetic risk score (GRS) was associated with higher urine albumin levels and eGFRcreatinine. The rs141640975 variant was also associated with higher levels of eGFRcreatinine-cystatin C (ml/min/1.73 m2, CKD-EPI2021, natural log-transformed) and lower circulating cystatin C levels. Conclusions: The positive associations between the four CUBN missense variants and eGFR in a large population without diabetes suggests a pleiotropic role of CUBN as a novel eGFR-locus in addition to it being a known albuminuria-locus. Additional associations with diverse renal function measures (lower cystatin C and higher eGFRcreatinine-cystatin C levels) and a CUBN-focused GRS further suggests an important role of CUBN in the future personalization of chronic kidney disease management in people without diabetes.
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