| 1. |
- Aspberg, A., et al.
(författare)
-
Cartilage oligomeric matrix protein forms protein complexes with synovial lubricin via non-covalent and covalent interactions
- 2017
-
Ingår i: Osteoarthritis and Cartilage. - : Elsevier BV. - 1063-4584. ; 25:9, s. 1496-1504
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: Understanding the cartilage surface structure, lost in arthritic disease, is essential for developing strategies to effectively restore it. Given that adherence of the lubricating protein, lubricin, to the cartilage surface is critical for boundary lubrication, an interaction with cartilage oligomeric matrix protein (COMP) was investigated. COMP, an abundant cartilage protein, is known to be important for matrix formation. Design: Synovial fluid (SF) from arthritic patients was used to detect possible COMP-lubricin complexes by immunological methods. Recombinant (RC) COMP and lubricin fragments were expressed to characterize this bonding and mass spectrometry employed to specifically identify the cysteines involved in inter-protein disulfide bonds. Results: COMP-lubricin complexes were identified in the SF of arthritic patients by Western blot, co-immunoprecipitation and sandwich ELISA. RC fragment solid-phase binding assays showed that the C-terminal (amino acids (AA) 518-757) of COMP bound non-covalently to the N-terminal of lubricin (AA 105-202). Mass spectrometry determined that although cysteines throughout COMP were involved in binding with lubricin, the cysteines in lubricin were primarily focused to an N-terminal region (AA 64-86). The close proximity of the non-covalent and disulfide binding domains on lubricin suggest a two-step mechanism to strongly bind lubricin to COMP. Conclusion: These data demonstrate that lubricin forms a complex network with COMP involving both non-covalent and covalent bonds. This complex between lubricin and the cartilage protein COMP can be identified in the SF of patients with arthritis conditions including osteoarthritis (OA) and rheumatoid arthritis (RA). (C) 2017 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.
|
|
| 2. |
- Coral, Daniel E, et al.
(författare)
-
A phenome-wide comparative analysis of genetic discordance between obesity and type 2 diabetes
- 2023
-
Ingår i: Nature Metabolism. - : Springer Science and Business Media LLC. - 2522-5812. ; 5:2, s. 237-247
-
Tidskriftsartikel (refereegranskat)abstract
- Obesity and type 2 diabetes are causally related, yet there is considerable heterogeneity in the consequences of both conditions and the mechanisms of action are poorly defined. Here we show a genetic-driven approach defining two obesity profiles that convey highly concordant and discordant diabetogenic effects. We annotate and then compare association signals for these profiles across clinical and molecular phenotypic layers. Key differences are identified in a wide range of traits, including cardiovascular mortality, fat distribution, liver metabolism, blood pressure, specific lipid fractions and blood levels of proteins involved in extracellular matrix remodelling. We find marginal differences in abundance of Bacteroidetes and Firmicutes bacteria in the gut. Instrumental analyses reveal prominent causal roles for waist-to-hip ratio, blood pressure and cholesterol content of high-density lipoprotein particles in the development of diabetes in obesity. We prioritize 17 genes from the discordant signature that convey protection against type 2 diabetes in obesity, which may represent logical targets for precision medicine approaches.
|
|
| 3. |
|
|
| 4. |
- Eloranta, Maija-Leena, et al.
(författare)
-
Type I interferon system activation and association with disease manifestations in systemic sclerosis
- 2010
-
Ingår i: Annals of the Rheumatic Diseases. - : BMJ. - 0003-4967 .- 1468-2060. ; 69:7, s. 1396-1402
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To study the presence of interferogenic autoantibodies in systemic sclerosis (SSc) and their correlation with clinical manifestations, serum levels of interferon alpha (IFNalpha) and chemokines of importance in the disease process. METHODS: Peripheral blood mononuclear cells (PBMCs) or purified plasmacytoid dendritic cells (pDCs) from healthy donors were stimulated with sera from patients with SSc (n=70) or healthy individuals (n=30), together with necrotic or apoptotic cell material. The IFNalpha produced and serum levels of IFNalpha, IFN-inducible protein-10 (IP-10)/chemokine (C-X-C motif) ligand 10, monocyte chemoattractant protein-1 (MCP-1)/(C-C motif) ligand-2 (CCL-2), macrophage inflammatory protein-1alpha (MIP-1alpha)/CCL-3 and RANTES/CCL-5 were measured and correlated with the presence of autoantibodies and clinical manifestations in the patients with SSc. RESULTS: Sera from both diffuse SSc and limited SSc contained interferogenic antibodies, which correlated with the presence of anti-ribonucleoprotein and anti-Sjögren syndrome antigen autoantibodies. The pDCs were responsible for the IFNalpha production which required interaction with FcgammaRII and endocytosis. Increased serum levels of IP-10 were associated with vascular manifestations such as cardiac involvement (p=0.027) and pulmonary arterial hypertension (p=0.036). Increased MCP-1 or IFNalpha serum levels were associated with lung fibrosis (p=0.019 and 0.048, respectively). Digital ulcers including digital loss were associated with increased serum levels of IFNalpha (p=0.029). CONCLUSION: An activated type I IFN system previously seen in several other systemic autoimmune diseases is also present in SSc and may contribute to the vascular pathology and affect the profibrotic process.
|
|
| 5. |
- Flowers, Sarah A., et al.
(författare)
-
Lubricin binds cartilage proteins, cartilage oligomeric matrix protein, fibronectin and collagen II at the cartilage surface
- 2017
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7
-
Tidskriftsartikel (refereegranskat)abstract
- Lubricin, a heavily O-glycosylated protein, is essential for boundary lubrication of articular cartilage. Strong surface adherence of lubricin is required given the extreme force it must withstand. Disulfide bound complexes of lubricin and cartilage oligomeric matrix protein (COMP) have recently been identified in arthritic synovial fluid suggesting they may be lost from the cartilage surface in osteoarthritis and inflammatory arthritis. This investigation was undertaken to localise COMP-lubricin complexes within cartilage and investigate if other cartilage proteins are involved in anchoring lubricin to the joint. Immunohistochemical analysis of human cartilage biopsies showed lubricin and COMP co-localise to the cartilage surface. COMP knockout mice, however, presented with a lubricin layer on the articular cartilage leading to the further investigation of additional lubricin binding mechanisms. Proximity ligation assays (PLA) on human cartilage biopsies was used to localise additional lubricin binding partners and demonstrated that lubricin bound COMP, but also fibronectin and collagen II on the cartilage surface. Fibronectin and collagen II binding to lubricin was confirmed and characterised by solid phase binding assays with recombinant lubricin fragments. Overall, COMP, fibronectin and collagen II bind lubricin, exposed on the articular cartilage surface suggesting they may be involved in maintaining essential boundary lubrication.
|
|
| 6. |
- Garcia-Calzon, Sonia, et al.
(författare)
-
Epigenetic markers associated with metformin response and intolerance in drug-naive patients with type 2 diabetes
- 2020
-
Ingår i: Science Translational Medicine. - : AMER ASSOC ADVANCEMENT SCIENCE. - 1946-6234 .- 1946-6242. ; 12:561
-
Tidskriftsartikel (refereegranskat)abstract
- Metformin is the first-line pharmacotherapy for managing type 2 diabetes (T2D). However, many patients with T2D do not respond to or tolerate metformin well. Currently, there are no phenotypes that successfully predict glycemic response to, or tolerance of, metformin. We explored whether blood-based epigenetic markers could discriminate metformin response and tolerance by analyzing genome-wide DNA methylation in drug-naive patients with T2D at the time of their diagnosis. DNA methylation of 11 and 4 sites differed between glycemic responders/nonresponders and metformin-tolerant/intolerant patients, respectively, in discovery and replication cohorts. Greater methylation at these sites associated with a higher risk of not responding to or not tolerating metformin with odds ratios between 1.43 and 3.09 per 1-SD methylation increase. Methylation risk scores (MRSs) of the 11 identified sites differed between glycemic responders and nonresponders with areas under the curve (AUCs) of 0.80 to 0.98. MRSs of the 4 sites associated with future metformin intolerance generated AUCs of 0.85 to 0.93. Some of these blood-based methylation markers mirrored the epigenetic pattern in adipose tissue, a key tissue in diabetes pathogenesis, and genes to which these markers were annotated to had biological functions in hepatocytes that altered metformin-related phenotypes. Overall, we could discriminate between glycemic responders/nonresponders and participants tolerant/intolerant to metformin at diagnosis by measuring blood-based epigenetic markers in drug-naive patients with T2D. This epigenetics-based tool may be further developed to help patients with T2D receive optimal therapy.
|
|
| 7. |
- García-Calzón, Sonia, et al.
(författare)
-
Epigenetic markers associated with metformin response and intolerance in drug-naïve patients with type 2 diabetes
- 2020
-
Ingår i: Science Translational Medicine. - 1946-6234. ; 12:561
-
Tidskriftsartikel (refereegranskat)abstract
- Metformin is the first-line pharmacotherapy for managing type 2 diabetes (T2D). However, many patients with T2D do not respond to or tolerate metformin well. Currently, there are no phenotypes that successfully predict glycemic response to, or tolerance of, metformin. We explored whether blood-based epigenetic markers could discriminate metformin response and tolerance by analyzing genome-wide DNA methylation in drug-naïve patients with T2D at the time of their diagnosis. DNA methylation of 11 and 4 sites differed between glycemic responders/nonresponders and metformin-tolerant/intolerant patients, respectively, in discovery and replication cohorts. Greater methylation at these sites associated with a higher risk of not responding to or not tolerating metformin with odds ratios between 1.43 and 3.09 per 1-SD methylation increase. Methylation risk scores (MRSs) of the 11 identified sites differed between glycemic responders and nonresponders with areas under the curve (AUCs) of 0.80 to 0.98. MRSs of the 4 sites associated with future metformin intolerance generated AUCs of 0.85 to 0.93. Some of these blood-based methylation markers mirrored the epigenetic pattern in adipose tissue, a key tissue in diabetes pathogenesis, and genes to which these markers were annotated to had biological functions in hepatocytes that altered metformin- related phenotypes. Overall, we could discriminate between glycemic responders/nonresponders and participants tolerant/ intolerant to metformin at diagnosis by measuring blood-based epigenetic markers in drug-naïve patients with T2D. This epigenetics-based tool may be further developed to help patients with T2D receive optimal therapy.
|
|
| 8. |
- Gheibi, Sevda, et al.
(författare)
-
Reduced Expression Level of Protein Phosphatase PPM1E Serves to Maintain Insulin Secretion in Type 2 Diabetes
- 2023
-
Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797. ; 72:4, s. 455-466
-
Tidskriftsartikel (refereegranskat)abstract
- Reversible phosphorylation is an important regulatory mechanism. Regulation of protein phosphorylation in β-cells has been extensively investigated, but less is known about protein dephosphorylation. To understand the role of protein dephosphorylation in β-cells and type 2 diabetes (T2D), we first examined mRNA expression of the type 2C family (PP2C) of protein phosphatases in islets from T2D donors. Phosphatase expression overall was changed in T2D, and that of PPM1E was the most markedly downregulated. PPM1E expression correlated inversely with HbA1c. Silencing of PPM1E increased glucose-stimulated insulin secretion (GSIS) in INS-1 832/13 cells and/or islets from patients with T2D, whereas PPM1E overexpression decreased GSIS. Increased GSIS after PPM1E silencing was associated with decreased oxidative stress, elevated cytosolic Ca2+ levels and ATP to ADP ratio, increased hyperpo-larization of the inner mitochondrial membrane, and phosphorylation of CaMKII, AMPK, and acetyl-CoA car-boxylase. Silencing of PPM1E, however, did not change insulin content. Increased GSIS, cell viability, and activation of AMPK upon metformin treatment in β-cells were observed upon PPM1E silencing. Thus, protein de-phosphorylation via PPM1E abrogates GSIS. Conse-quently, reduced PPM1E expression in T2D may be a compensatory response of β-cells to uphold insulin secretion under metabolic duress. Targeting PPM1E in β-cells may thus represent a novel therapeutic strategy for treatment of T2D.
|
|
| 9. |
- Huang, M., et al.
(författare)
-
CRISPR editing of the PPARGC1A Gly482ser (rs8192678) polymorphism in human white adipose cells shows differential effects on mitochondrial function and adipogenesis.
- 2021
-
Ingår i: Diabetologia. - : Springer Science and Business Media LLC. - 1432-0428 .- 0012-186X. ; 64:Suppl 1, s. 159-159
-
Konferensbidrag (refereegranskat)abstract
- Background and aims: PPARGC1A encodes PGC-1α (peroxisome proliferator-activated receptor γ coactivator 1-α), a central regulator of energy metabolism and mitochondrial function. A common polymorphism in PPARGC1A (rs8192678, C/T, Gly482Ser) has been associated with obesity and related metabolic disorders, but no published functional studies have investigated direct allele-specific effects in adipocyte biology. Materials and methods: We used CRISPR-Cas9 to perform allele switching (C-to-T or T-to-C) at rs8192678 in isogenic human pre-adipocyte white adipose tissue (hWAT) cell line; we then evaluated the allelic effects at rs8192678 on adipogenic differentiation and mitochondrial function. Accordingly, single-cell clones were expanded and screened to obtain homozygous T/T (482Ser) and C/C (482Gly) isogenic cell populations. The effect of the allele editing on white adipocyte differentiation and on mitochondrial function was then studied in three cell populations of the respective genotype. In ongoing experiments, CRISPR/Cas9 was also used to append a luciferase tag to C/C and in T/T cells. The luciferase will be used as a reporter for the endogenously expressed PGC-1 protein stability, and will therefore provide insights into mechanisms by which rs8192678 alleles affect PGC-1 activity. Results (see figure): At the end of the differentiation protocol the C/C adipocytes were apparently less Oil-Red-O positive than T/T adipocytes under optical microscopy, they had 78.5% lower triglyceride content (p<0.0001, n=9), and lower expression of adipogenic markers (all markers p<0.0001, n=3). Furthermore, C/C adipocytes had lower mitochondrial content (p<0.001, n=9), which coincided with decreased oxygen consumption rate (OCR) at basal (p<0.0001, n=3) and maximal respiration (p<0.0001, n=3). Also, C/C adipocytes had lower ATP-linked OCR (p<0.0001, n=3). Conclusion: Our data showcases discriminatory causal effects of the two rs8192678 alleles in adipocytes. The C allele confers lower PPARGC1A expression, and consequential impaired adipocyte differentiation, at least in part due to disrupted mitochondrial biosynthesis and function. Our study is the first to give experimental insights into the molecular mechanisms behind observational epidemiological studies the Gly482Ser variant and obesity and metabolic disorders
|
|
| 10. |
- Huang, Mi, et al.
(författare)
-
Engineered allele substitution at PPARGC1A rs8192678 alters human white adipocyte differentiation, lipogenesis, and PGC-1α content and turnover
- 2023
-
Ingår i: Diabetologia. - 1432-0428. ; 66:7, s. 1289-1305
-
Tidskriftsartikel (refereegranskat)abstract
- Aims/hypothesisPPARGC1A encodes peroxisome proliferator-activated receptor γ coactivator 1-α (PGC-1α), a central regulator of energy metabolism and mitochondrial function. A common polymorphism in PPARGC1A (rs8192678, C/T, Gly482Ser) has been associated with obesity and related metabolic disorders, but no published functional studies have investigated direct allele-specific effects in adipocyte biology. We examined whether rs8192678 is a causal variant and reveal its biological function in human white adipose cells.MethodsWe used CRISPR-Cas9 genome editing to perform an allelic switch (C-to-T or T-to-C) at rs8192678 in an isogenic human pre-adipocyte white adipose tissue (hWAs) cell line. Allele-edited single-cell clones were expanded and screened to obtain homozygous T/T (Ser482Ser), C/C (Gly482Gly) and heterozygous C/T (Gly482Ser) isogenic cell populations, followed by functional studies of the allele-dependent effects on white adipocyte differentiation and mitochondrial function.ResultsAfter differentiation, the C/C adipocytes were visibly less BODIPY-positive than T/T and C/T adipocytes, and had significantly lower triacylglycerol content. The C allele presented a dose-dependent lowering effect on lipogenesis, as well as lower expression of genes critical for adipogenesis, lipid catabolism, lipogenesis and lipolysis. Moreover, C/C adipocytes had decreased oxygen consumption rate (OCR) at basal and maximal respiration, and lower ATP-linked OCR. We determined that these effects were a consequence of a C-allele-driven dysregulation of PGC-1α protein content, turnover rate and transcriptional coactivator activity.Conclusions/interpretationOur data show allele-specific causal effects of the rs8192678 variant on adipogenic differentiation. The C allele confers lower levels of PPARGC1A mRNA and PGC-1α protein, as well as disrupted dynamics of PGC-1α turnover and activity, with downstream effects on cellular differentiation and mitochondrial function. Our study provides the first experimentally deduced insights on the effects of rs8192678 on adipocyte phenotype.
|
|
