| 1. |
- AbdGawad, Mohamed, et al.
(författare)
-
Decreased Neutrophil Apoptosis in Quiescent ANCA-Associated Systemic Vasculitis
- 2012
-
Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 7:3
-
Tidskriftsartikel (refereegranskat)abstract
- Background: ANCA-Associated Systemic Vasculitis (AASV) is characterized by leukocytoclasis, accumulation of unscavenged apoptotic and necrotic neutrophils in perivascular tissues. Dysregulation of neutrophil cell death may contribute directly to the pathogenesis of AASV. less thanbrgreater than less thanbrgreater thanMethods: Neutrophils from Healthy Blood Donors (HBD), patients with AASV most in complete remission, Polycythemia Vera (PV), Systemic Lupus Erythematosus (SLE), Rheumatoid Arthritis (RA) and renal transplant recipients (TP) were incubated in vitro, and the rate of spontaneous apoptosis was measured by FACS. Plasma levels of cytokines and sFAS were measured with cytometric bead array and ELISA. Expression of pro/anti-apoptotic factors, transcription factors C/EBP-alpha, C/EBP-beta and PU.1 and inhibitors of survival/JAK2-pathway were measured by real-time-PCR. less thanbrgreater than less thanbrgreater thanResults: AASV, PV and RA neutrophils had a significantly lower rate of apoptosis compared to HBD neutrophils (AASV 50 +/- 14% vs. HBD 64 +/- 11%, p andlt; 0.0001). In RA but not in AASV and PV, low apoptosis rate correlated with increased plasma levels of GM-CSF and high mRNA levels of anti-apoptotic factors Bcl-2A1 and Mcl-1. AASV patients had normal levels of G-CSF, GM-CSF and IL-3. Both C/EBP-alpha, C/EBP-beta were significantly higher in neutrophils from AASV patients than HBD. Levels of sFAS were significantly higher in AASV compared to HBD. less thanbrgreater than less thanbrgreater thanConclusion: Neutrophil apoptosis rates in vitro are decreased in AASV, RA and PV but mechanisms seem to differ. Increased mRNA levels of granulopoiesis-associated transcription factors and increased levels of sFAS in plasma were observed in AASV. Additional studies are required to define the mechanisms behind the decreased apoptosis rates, and possible connections with accumulation of dying neutrophils in regions of vascular lesions in AASV patients.
|
|
| 2. |
- AbdGawad, Mohamed, et al.
(författare)
-
Elevated neutrophil membrane expression of proteinase 3 is dependent upon CD177 expression
- 2010
-
Ingår i: Clinical and Experimental Immunology. - Chichester, West Sussex, United Kingdom : Wiley-Blackwell. - 0009-9104 .- 1365-2249. ; 161:1, s. 89-97
-
Tidskriftsartikel (refereegranskat)abstract
- Proteinase 3 (PR3) is a major autoantigen in anti-neutrophil cytoplasmic antibodies (ANCA)-associated systemic vasculitis (AASV), and the proportion of neutrophils expressing PR3 on their membrane (mPR3+) is increased in AASV. We have shown recently that mPR3 and CD177 are expressed on the same cells in healthy individuals. In this study we try to elucidate mechanisms behind the increased mPR3 expression in AASV and its relationship to CD177. All neutrophils in all individuals were either double-positive or double-negative for mPR3 and CD177. The proportion of double-positive neutrophils was increased significantly in AASV and systemic lupus erythematosus patients. The proportion of mPR3+/CD177+ cells was not correlated to general inflammation, renal function, age, sex, drug treatment and levels of circulating PR3. AASV patients had normal levels of granulocyte colony-stimulating factor and granulocyte–macrophage colony-stimulating factor. Pro-PR3 was found to constitute 10% of circulating PR3 but none of the mPR3. We found increased mRNA levels of both PR3 and CD177 in AASV, but they did not correlate with the proportion of double-positive cells. In cells sorted based on membrane expression, CD177–mRNA was several-fold higher in mPR3+ cells. When exogenous PR3 was added to CD177-transfected U937 cells, only CD177+ cells bound PR3 to their membrane. In conclusion, the increased membrane expression of PR3 found in AASV is not linked directly to circulating PR3 or PR3 gene transcription, but is dependent upon CD177 expression and correlated with the transcription of the CD177 gene.
|
|
| 3. |
- AbdGawad, Mohamed, et al.
(författare)
-
Increased neutrophil membrane expression and plasma level of proteinase 3 in systemic vasculitis are not a consequence of the - 564 A/G promotor polymorphism.
- 2006
-
Ingår i: Clinical and Experimental Immunology. - : Oxford University Press (OUP). - 0009-9104 .- 1365-2249. ; 145:1, s. 63-70
-
Tidskriftsartikel (refereegranskat)abstract
- Several findings link proteinase 3 (PR3) to small vessel vasculitis. Besides being a major target of anti-neutrophil cytoplasm antibodies (ANCA), previous findings have shown increased circulating levels of PR3 in vasculitis patients, increased levels of neutrophil membrane-PR3 (mPR3) expression and a skewed distribution of the − 564 A/G polymorphism in the promotor region of the PR3 gene. In this study we elucidate how these three findings relate to each other. The plasma concentration of PR3 was measured by enzyme-linked immunosorbent assay (ELISA), mPR3 expression by fluorescence activated cell sorter (FACS) and the gene polymorphism by real-time polymerase chain reaction (PCR). We compared results from 63 patients with ANCA-associated systemic vasculitis (AASV) with 107 healthy blood donors. In accordance with previous reports, AASV patients had increased plasma concentrations of PR3 compared to healthy controls (mean 224 µg/l versus 155 µg/l, P < 0·0001). They also showed an increased number of mPR3-positive neutrophils (60% versus 42%, P < 0·001). However, contrary to a previous report, we found no skewed distribution of the polymorphism in PR3 gene. There was a weak correlation between mPR3 mean fluorescence intensity (MFI) and plasma PR3 among healthy controls and myeloperoxidase–ANCA (MPO–ANCA)-positive patients (r = 0·24, P = 0·015 and r = 0·52, P = 0·011, respectively). In conclusion, increased plasma PR3 and high expression of mPR3 are associated with small vessel vasculitis, but neither of them is a consequence of the − 564 A/G polymorphism of the PR3 gene promotor.
|
|
| 4. |
|
|
| 5. |
- AbdGawad, Mohamed
(författare)
-
Proteinase 3 and Neutrophil Apoptosis in ANCA-Associated Systemic Vasculitis
- 2010
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- ANCA-Associated Systemic Vasculitis (AASV) is characterized by leukocytoclasis- dying neutrophils surrounding small blood vessels. Previous studies have shown increased plasma PR3 and increased proportion of neutrophils expressing plasma membrane-associated PR3 (mPR3+). Neutrophils were isolated by polymorphprep and membrane expression was measured by FACS. Plasma PR3, pro-PR3 and cytokines were measured by ELISA. Neutrophil apoptosis was measured by FACS after 20h in vitro culture. Expression of pro/anti-apoptotic factors and transcription factors C/EBP-α, C/EBP-β and PU.1 was measured by real-time PCR. Plasma PR3, pro-PR3, and proportion of mPR3+neutrophils were elevated in AASV. mPR3 and CD177 were co-expressed on a subset of neutrophils both in AASV and controls. mPR3 expression was not correlated directly to circulating PR3 or PR3 gene transcription, but was dependent on transcription of the CD177 gene. AASV neutrophils had a significantly lower rate of apoptosis than neutrophils from healthy blood donors (HBD). Lower apoptosis rate did not correlate with clinical data, plasma PR3, cytokine levels, mPR3 expression or level of pro/anti-apoptotic factors. However, C/EBP-α and C/EBP-β were significantly higher in neutrophils from AASV patients than in HBD neutrophils. These results indicate an altered neutrophil phenotype in AASV and suggest that the rate of granulopoiesis is higher, while the rate of neutrophil apoptosis is lower. This may predispose for the presence of dying neutrophils in regions of inflammation in AASV. Additional studies are required to determine why the rate of neutrophil apoptosis is lower in AASV patients and if dysregulation of neutrophil apoptosis contributes directly to the pathogenesis.
|
|
| 6. |
|
|
| 7. |
- Bauer, Susanne, et al.
(författare)
-
Proteinase 3 and CD177 are expressed on the plasma membrane of the same subset of neutrophils.
- 2007
-
Ingår i: Journal of Leukocyte Biology. - : Oxford University Press (OUP). - 1938-3673 .- 0741-5400. ; 81, s. 458-464
-
Tidskriftsartikel (refereegranskat)abstract
- Proteinase 3 (PR3) is found in granules of all nentrophils but also on the plasma membrane of a subset of nentrophils (mPR3). CD177, another neutrophil protein, also displays a bimodal surface expression. In this study, we have investigated the coexpression of these two molecules, as well as the effect of cell activation on their surface expression. We can show that CD177 is expressed on the same subset of nentrophils as mPR3. Experiments show that the expression of mPR3 and CD177 on the plasma membrane is increased or decreased in parallel during cell stimulation or spontaneous apoptosis. Furthermore, we observed a rapid internalization and recirculation of mPR3 and plasma membrane CD177, where A mPR3 is replaced within 30 min. Our findings suggest that the PR3 found on the plasma membrane has its origin in the same intracellular storage as CD177, i.e., secondary granules and secretory vesicles and not primary granules. PR3- and CD177-expressing neutrophils constitute a subpopulation of neutrophils with an unknown role in the innate immune system, which may play an important role in diseases such as Wegener's granulomatosis and polycythemia vera.
|
|
