| 1. |
- Christensson, Marta, et al.
(författare)
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Serum sFAS levels are elevated in ANCA-positive vasculitis compared with other autoimmune diseases
- 2002
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Ingår i: Journal of Clinical Immunology. - 0271-9142 .- 1573-2592. ; 22:4, s. 220-227
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Tidskriftsartikel (refereegranskat)abstract
- The role of the Fas/FasL system in ANCA-associated vasculitis is unclear. We therefore assessed levels of soluble Fas (sFas) in sera and Fas expression on mononuclear cells from patients with ANCA-positive vasculitis and compared the results with those found in other rheumatic diseases. Serum levels of sFas were determined by ELISA. The ANCA-positive vasculitis patients studied included 29 at onset, 17 in first remission while on therapy, and 12 in quiescence. For comparison, 10 patients with Sjogren’s syndrome (SS), 14 patients with systemic lupus erythematosus (SLE), 29 patients with rheumatoid arthritis (RA), 7 patients on dialysis (DP), and 26 healthy controls (HC) were studied. In addition, Fas expression in mononuclear cells was examined at the mRNA level using reverse transcriptase (RT)-PCR in 6 vasculitis patients at onset and in first remission. The expression of CD95 on the surface of leukocytes was determined by flow cytometry in 6 vasculitis patients at onset of the disease, in 6 patients in clinical remission, and in 6 HC. Expression of Fas and FasL in renal biopsy specimens was studied using immunohistochemistry. Patients with vasculitis had high sFas levels irrespective of disease phase. Both vasculitis patients and patients with RA and SLE had significantly increased sFas levels compared with healthy controls. All patient groups had sFas levels, which correlated with raised serum creatinine values. However, the sFas levels in vasculitis patients in first remission and in quiescence were increased despite a lower serum creatinine compared with onset. Some of the vasculitis patients showed an increased mRNA expression of Fas in mononuclear cells after treatment, suggesting that Fas production fluctuates with the intensity of the disease. The expression of CD95 on leukocytes was slightly decreased in vasculitis patients compared to healthy controls. No alterations of Fas and FasL expression were seen in renal biopsy specimens. These results show that ANCA-positive vasculitis patients have high sFas levels and that the levels remain elevated even in clinical remission. The findings indicate that perturbations in the Fas/Fas ligand system may play a role in the disease process in ANCA vasculitis.
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| 2. |
- Abdelrazak Morsy, Mohammad Hamdy, et al.
(författare)
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SOX11 is a novel binding partner and endogenous inhibitor of SAMHD1 ara-CTPase activity in mantle cell lymphoma
- 2024
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 143:19, s. 1953-1964
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Tidskriftsartikel (refereegranskat)abstract
- Sterile alpha motif and histidine-aspartate (HD) domain-containing protein 1 (SAMHD1) is a deoxynucleoside triphosphate triphosphohydrolase with ara-CTPase activity that confers cytarabine (ara -C) resistance in several hematological malignancies. Targeting SAMHD1's ara-CTPase activity has recently been demonstrated to enhance ara -C ef fi cacy in acute myeloid leukemia. Here, we identify the transcription factor SRY-related HMGbox containing protein 11 (SOX11) as a novel direct binding partner and fi rst known endogenous inhibitor of SAMHD1. SOX11 is aberrantly expressed not only in mantle cell lymphoma (MCL), but also in some Burkitt lymphomas. Coimmunoprecipitation of SOX11 followed by mass spectrometry in MCL cell lines identi fi ed SAMHD1 as the top SOX11 interaction partner, which was validated by proximity ligation assay. In vitro, SAMHD1 bound to the HMG box of SOX11 with low-micromolar af fi nity. In situ crosslinking studies further indicated that SOX11-SAMHD1 binding resulted in a reduced tetramerization of SAMHD1. Functionally, expression of SOX11 inhibited SAMHD1 ara-CTPase activity in a dose-dependent manner resulting in ara -C sensitization in cell lines and in a SOX11-inducible mouse model of MCL. In SOX11-negative MCL, SOX11-mediated ara-CTPase inhibition could be mimicked by adding the recently identi fi ed SAMHD1 inhibitor hydroxyurea. Taken together, our results identify SOX11 as a novel SAMHD1 interaction partner and its fi rst known endogenous inhibitor with potentially important implications for clinical therapy strati fi cation.
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| 3. |
- Christensson, Marta
(författare)
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Immunological studies on anca-associated vasculitis with special reference to T cell activation
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis focuses on the role of T cells in ANCA-associated vasculitis. We initially investigated activation markers on T cells in patients with Wegener's granulomatosis (WG), microscopic polyangiitis (MPA) and renal limited disease (RLD) and found increased expression indicating continuous activation despite clinical remission. As apoptosis maintains homeostatic control of lymphocyte populations we examined its role in WG, MPA and RLD in comparison with patients with rheumatoid arthritis, lupus erythematosus and Sjögren´s syndrome. We found that patients with ANCApositive vasculitis have high serum levels of soluble Fas (sFas) that remain elevated even in clinical remission. In our third paper we studied the influence of chemokines on the cell surface expression of thrombospondin-1 (TSP-1) in T cells. The results demonstrate a chemokine-dependent CD26-controlled regulation of T cell polarity and migration through endogenous TSP-1. Based on the results in the third paper we then studied patients with ANCA positive vasculitis with respect to serum levels of chemokines, T cell mRNA expression of chemokine receptors, and possible influence of CD26 on TSP-1 expression. We found altered chemokine levels and evidence for impaired CD26 suppression of chemokine-dependent TSP-1 expression in vasculitis patients in comparison with patients with asthma suggesting that a mechanism for negative regulation of T cell migration is suppressed in these patients. These findings suggest that T cells play an important role in ANCA associated vasculitis and may be useful targets in the development of therapeutic strategies.
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