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Silencing of renal DNaseI in murine lupus nephritis imposes exposure of large chromatin fragments and activation of Toll like receptors and the Clec4e.

Thiyagarajan D, Fismen S, Seredkina N, Jacobsen S, Elung-Jensen T, Kamper AL, Fenton CG, Rekvig OP, Mortensen ES - PLoS ONE (2012)

Bottom Line: Down-regulation of DNaseI results in reduced chromatin fragmentation, and in deposition of extracellular chromatin-IgG complexes in glomerular basement membranes in individuals that produce IgG anti-chromatin antibodies.Mouse and human mRNA expression levels of DNaseI, Toll like receptors 7-9, Clec4e, pro-inflammatory cytokines and MMP2/MMP9 were determined and compared with in situ protein expression profiles and clinical data.In conclusion, silencing of renal DNaseI gene expression initiates a cascade of inflammatory signals leading to progression of both murine and human lupus nephritis.

View Article: PubMed Central - PubMed

Affiliation: Molecular Pathology Research Group, Faculty of Medicine, University of Tromsø, Tromsø, Norway.

ABSTRACT
Recent studies demonstrate that transformation of mild lupus nephritis into end-stage disease is imposed by silencing of renal DNaseI gene expression in (NZBxNZW)F1 mice. Down-regulation of DNaseI results in reduced chromatin fragmentation, and in deposition of extracellular chromatin-IgG complexes in glomerular basement membranes in individuals that produce IgG anti-chromatin antibodies. The main focus of the present study is to describe the biological consequences of renal DNaseI shut-down and reduced chromatin fragmentation with a particular focus on whether exposed large chromatin fragments activate Toll like receptors and the necrosis-related Clec4e receptor in murine and human lupus nephritis. Furthermore, analyses where performed to determine if matrix metalloproteases are up-regulated as a consequence of chromatin-mediated Toll like receptors/Clec4e stimulation. Mouse and human mRNA expression levels of DNaseI, Toll like receptors 7-9, Clec4e, pro-inflammatory cytokines and MMP2/MMP9 were determined and compared with in situ protein expression profiles and clinical data. We demonstrate that exposure of chromatin significantly up-regulate Toll like receptors and Clec4e in mice, and also but less pronounced in patients with lupus nephritis treated with immunosuppresants. In conclusion, silencing of renal DNaseI gene expression initiates a cascade of inflammatory signals leading to progression of both murine and human lupus nephritis. Principal component analyses biplot of data from murine and human lupus nephrits demonstrate the importance of DNaseI gene shut down for progression of the organ disease.

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Related in: MedlinePlus

Expression of the MMP2 and MMP9 in kidneys of BW mice.Data demonstrate an insignificant increase in renal MMP2, but not in MMP9 mRNA levels in Group 3 mice compared with mice from Group 1 and 2 (A), and a corresponding increase in MMP2 protein (western blot, B) or in activated MMP2 (zymography, C). Serum concentrations of MMP2 and MMP9 were stable in all stages of the disease as demonstrated by quantitative ELISA for MMP2 and MMP9 (Figure 3D). In agreement with the hypothesis that MMP2 gene expression is linked to activation of TLRs, TLR8 correlates significantly with expression of MMP2 (r = 0,63, p<0,001, E).
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pone-0034080-g003: Expression of the MMP2 and MMP9 in kidneys of BW mice.Data demonstrate an insignificant increase in renal MMP2, but not in MMP9 mRNA levels in Group 3 mice compared with mice from Group 1 and 2 (A), and a corresponding increase in MMP2 protein (western blot, B) or in activated MMP2 (zymography, C). Serum concentrations of MMP2 and MMP9 were stable in all stages of the disease as demonstrated by quantitative ELISA for MMP2 and MMP9 (Figure 3D). In agreement with the hypothesis that MMP2 gene expression is linked to activation of TLRs, TLR8 correlates significantly with expression of MMP2 (r = 0,63, p<0,001, E).

Mentions: Data in Figure 3 demonstrate an insignificant increase in renal MMP2, but not in MMP9 mRNA levels (Figure 3A), and a corresponding increase in MMP2 protein (western blot, Figure 3B) or in activated MMP2 (zymography, Figure 3C) in Group 3 kidneys. On the other hand, serum concentrations of MMP2 and MMP9 were stable in all stages of the disease as demonstrated by quantitative ELISA for MMP2 and MMP9 (Figure 3D). In agreement with the hypothesis that MMP2 gene expression is linked to activation of TLRs, e.g. TLR8 correlates significantly with expression of MMP2 (r = 0,63, p<0,001, Figure 3E).


Silencing of renal DNaseI in murine lupus nephritis imposes exposure of large chromatin fragments and activation of Toll like receptors and the Clec4e.

Thiyagarajan D, Fismen S, Seredkina N, Jacobsen S, Elung-Jensen T, Kamper AL, Fenton CG, Rekvig OP, Mortensen ES - PLoS ONE (2012)

Expression of the MMP2 and MMP9 in kidneys of BW mice.Data demonstrate an insignificant increase in renal MMP2, but not in MMP9 mRNA levels in Group 3 mice compared with mice from Group 1 and 2 (A), and a corresponding increase in MMP2 protein (western blot, B) or in activated MMP2 (zymography, C). Serum concentrations of MMP2 and MMP9 were stable in all stages of the disease as demonstrated by quantitative ELISA for MMP2 and MMP9 (Figure 3D). In agreement with the hypothesis that MMP2 gene expression is linked to activation of TLRs, TLR8 correlates significantly with expression of MMP2 (r = 0,63, p<0,001, E).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3316608&req=5

pone-0034080-g003: Expression of the MMP2 and MMP9 in kidneys of BW mice.Data demonstrate an insignificant increase in renal MMP2, but not in MMP9 mRNA levels in Group 3 mice compared with mice from Group 1 and 2 (A), and a corresponding increase in MMP2 protein (western blot, B) or in activated MMP2 (zymography, C). Serum concentrations of MMP2 and MMP9 were stable in all stages of the disease as demonstrated by quantitative ELISA for MMP2 and MMP9 (Figure 3D). In agreement with the hypothesis that MMP2 gene expression is linked to activation of TLRs, TLR8 correlates significantly with expression of MMP2 (r = 0,63, p<0,001, E).
Mentions: Data in Figure 3 demonstrate an insignificant increase in renal MMP2, but not in MMP9 mRNA levels (Figure 3A), and a corresponding increase in MMP2 protein (western blot, Figure 3B) or in activated MMP2 (zymography, Figure 3C) in Group 3 kidneys. On the other hand, serum concentrations of MMP2 and MMP9 were stable in all stages of the disease as demonstrated by quantitative ELISA for MMP2 and MMP9 (Figure 3D). In agreement with the hypothesis that MMP2 gene expression is linked to activation of TLRs, e.g. TLR8 correlates significantly with expression of MMP2 (r = 0,63, p<0,001, Figure 3E).

Bottom Line: Down-regulation of DNaseI results in reduced chromatin fragmentation, and in deposition of extracellular chromatin-IgG complexes in glomerular basement membranes in individuals that produce IgG anti-chromatin antibodies.Mouse and human mRNA expression levels of DNaseI, Toll like receptors 7-9, Clec4e, pro-inflammatory cytokines and MMP2/MMP9 were determined and compared with in situ protein expression profiles and clinical data.In conclusion, silencing of renal DNaseI gene expression initiates a cascade of inflammatory signals leading to progression of both murine and human lupus nephritis.

View Article: PubMed Central - PubMed

Affiliation: Molecular Pathology Research Group, Faculty of Medicine, University of Tromsø, Tromsø, Norway.

ABSTRACT
Recent studies demonstrate that transformation of mild lupus nephritis into end-stage disease is imposed by silencing of renal DNaseI gene expression in (NZBxNZW)F1 mice. Down-regulation of DNaseI results in reduced chromatin fragmentation, and in deposition of extracellular chromatin-IgG complexes in glomerular basement membranes in individuals that produce IgG anti-chromatin antibodies. The main focus of the present study is to describe the biological consequences of renal DNaseI shut-down and reduced chromatin fragmentation with a particular focus on whether exposed large chromatin fragments activate Toll like receptors and the necrosis-related Clec4e receptor in murine and human lupus nephritis. Furthermore, analyses where performed to determine if matrix metalloproteases are up-regulated as a consequence of chromatin-mediated Toll like receptors/Clec4e stimulation. Mouse and human mRNA expression levels of DNaseI, Toll like receptors 7-9, Clec4e, pro-inflammatory cytokines and MMP2/MMP9 were determined and compared with in situ protein expression profiles and clinical data. We demonstrate that exposure of chromatin significantly up-regulate Toll like receptors and Clec4e in mice, and also but less pronounced in patients with lupus nephritis treated with immunosuppresants. In conclusion, silencing of renal DNaseI gene expression initiates a cascade of inflammatory signals leading to progression of both murine and human lupus nephritis. Principal component analyses biplot of data from murine and human lupus nephrits demonstrate the importance of DNaseI gene shut down for progression of the organ disease.

Show MeSH
Related in: MedlinePlus