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Novel Autoantigens Associated with Lupus Nephritis.

Onishi S, Adnan E, Ishizaki J, Miyazaki T, Tanaka Y, Matsumoto T, Suemori K, Shudou M, Okura T, Takeda H, Sawasaki T, Yasukawa M, Hasegawa H - PLoS ONE (2015)

Bottom Line: To obtain other autoantibodies associated with LN, we screened autoantigens reacting with the sera of LN patients by using an N-terminal biotinylated protein library created from a wheat cell-free protein production system.Both proteins are cationic, and their respective antibodies did not cross-react with dsDNA.These autoantibodies may be useful for prediction of LN in subsets of SLE patients who are negative for anti-dsDNA antibodies.

View Article: PubMed Central - PubMed

Affiliation: Department of Hematology, Clinical Immunology and Infectious Diseases, Ehime University Graduate School of Medicine, Ehime, Japan.

ABSTRACT
Systemic lupus erythematosus (SLE) is characterized by production of a variety of autoantibodies. Although anti-double-stranded DNA (anti-dsDNA) antibodies contribute to the pathogenesis of lupus nephritis (LN), they are not sufficient for diagnosis and evaluation of disease activity. To obtain other autoantibodies associated with LN, we screened autoantigens reacting with the sera of LN patients by using an N-terminal biotinylated protein library created from a wheat cell-free protein production system. We screened 17 proteins that showed higher positive signals in the active phase than in the inactive phase of SLE, and higher positive signals in the serum of SLE patient with nephritis than in that of patient without nephritis. Of these, two LN-associated autoantigens, ribosomal RNA-processing protein 8 (RRP8) and spermatid nuclear transition protein 1 (TNP1) were identified by immunoprecipitation and immunofluorescence of renal tissues. Circulating anti-RRP8 and anti-TNP1 autoantibodies were recognized and deposited as an immune complex (IC) in glomeruli. IC was deposited preferentially in glomeruli rather than in other organs in C57BL/6 mice injected with RRP8 or TNP1. ELISA analysis of sera from patients with various rheumatic diseases demonstrated reactivity for RRP8 and TNP1 in 20% and 14.7% of SLE patients, respectively, whereas there was little or no reactivity in patients with other rheumatic diseases. Among SLE patients, 63.6% and 45.5% of those with LN were positive for anti-RRP8 and anti-TNP1 antibodies, compared with 12.5% and 9.4% of SLE patients without nephritis, respectively. Both proteins are cationic, and their respective antibodies did not cross-react with dsDNA. These proteins released from apoptotic cells form ICs with each autoantibody, and their ICs may become trapped at anionic sites in the glomerular basement membrane, leading to deposition in glomeruli. These autoantibodies may be useful for prediction of LN in subsets of SLE patients who are negative for anti-dsDNA antibodies.

No MeSH data available.


Related in: MedlinePlus

Analysis of infiltrating cells (A) and cytokine expression (B) in the kidneys of RRP8-injected and TNP1-injected mice.(A) Quantitative analysis of mononuclear cells in glomerular and tubulointerstitial areas was performed in control, RRP8-injected and TNP1-injected mice. Values are the mean and SD of infiltrating and parenchymal cells (glomerular, cell counts in 20 random glomeruli; and tubulointerstitial, 10 random fields at x400 magnification). (B) qRT-PCR analysis was performed on total RNA prepared from kidneys of all mice of each group. Results are calculated as a ratio of cytokine expression to the expression of HPRT1. * no positive signal with 45 cycles.
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pone.0126564.g009: Analysis of infiltrating cells (A) and cytokine expression (B) in the kidneys of RRP8-injected and TNP1-injected mice.(A) Quantitative analysis of mononuclear cells in glomerular and tubulointerstitial areas was performed in control, RRP8-injected and TNP1-injected mice. Values are the mean and SD of infiltrating and parenchymal cells (glomerular, cell counts in 20 random glomeruli; and tubulointerstitial, 10 random fields at x400 magnification). (B) qRT-PCR analysis was performed on total RNA prepared from kidneys of all mice of each group. Results are calculated as a ratio of cytokine expression to the expression of HPRT1. * no positive signal with 45 cycles.

Mentions: Next, we analyzed the infiltrating cells in glomerular and tubulointerstitial areas in control, RRP8-injected and TNP1-injected mice. As shown in Fig 9A, there was no significant difference in the composition of infiltrating cells in glomerular and tubulointerstitial areas between RRP8-injected and TNP1-injected mice. The majority of the infiltrating cells were CD11b-positive (macrophages) and CD3-positive (pan-T cells) in the kidneys of RRP8-injected and TNP1-injected mice. In the glomerulus, the numbers of infiltrating macrophages and T cells in RRP8-injected and TNP1-injected mice were 5-fold and 2-fold higher than those in control mice, respectively. In the tubulointerstitium, the numbers of infiltrating macrophages and T cells in RRP8-injected and TNP1-injected mice were 2-fold and 4-fold higher than those in control mice, respectively. These findings indicate that macrophages in the glomerulus and T cells in the tubulointerstitium predominantly infiltrate the kidneys of RRP8-injected and TNP1-injected mice. Among CD3-positive cells in the glomerulus and tubulointerstitium, the proportions of CD4- and CD8-positive cells were similar.


Novel Autoantigens Associated with Lupus Nephritis.

Onishi S, Adnan E, Ishizaki J, Miyazaki T, Tanaka Y, Matsumoto T, Suemori K, Shudou M, Okura T, Takeda H, Sawasaki T, Yasukawa M, Hasegawa H - PLoS ONE (2015)

Analysis of infiltrating cells (A) and cytokine expression (B) in the kidneys of RRP8-injected and TNP1-injected mice.(A) Quantitative analysis of mononuclear cells in glomerular and tubulointerstitial areas was performed in control, RRP8-injected and TNP1-injected mice. Values are the mean and SD of infiltrating and parenchymal cells (glomerular, cell counts in 20 random glomeruli; and tubulointerstitial, 10 random fields at x400 magnification). (B) qRT-PCR analysis was performed on total RNA prepared from kidneys of all mice of each group. Results are calculated as a ratio of cytokine expression to the expression of HPRT1. * no positive signal with 45 cycles.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4476694&req=5

pone.0126564.g009: Analysis of infiltrating cells (A) and cytokine expression (B) in the kidneys of RRP8-injected and TNP1-injected mice.(A) Quantitative analysis of mononuclear cells in glomerular and tubulointerstitial areas was performed in control, RRP8-injected and TNP1-injected mice. Values are the mean and SD of infiltrating and parenchymal cells (glomerular, cell counts in 20 random glomeruli; and tubulointerstitial, 10 random fields at x400 magnification). (B) qRT-PCR analysis was performed on total RNA prepared from kidneys of all mice of each group. Results are calculated as a ratio of cytokine expression to the expression of HPRT1. * no positive signal with 45 cycles.
Mentions: Next, we analyzed the infiltrating cells in glomerular and tubulointerstitial areas in control, RRP8-injected and TNP1-injected mice. As shown in Fig 9A, there was no significant difference in the composition of infiltrating cells in glomerular and tubulointerstitial areas between RRP8-injected and TNP1-injected mice. The majority of the infiltrating cells were CD11b-positive (macrophages) and CD3-positive (pan-T cells) in the kidneys of RRP8-injected and TNP1-injected mice. In the glomerulus, the numbers of infiltrating macrophages and T cells in RRP8-injected and TNP1-injected mice were 5-fold and 2-fold higher than those in control mice, respectively. In the tubulointerstitium, the numbers of infiltrating macrophages and T cells in RRP8-injected and TNP1-injected mice were 2-fold and 4-fold higher than those in control mice, respectively. These findings indicate that macrophages in the glomerulus and T cells in the tubulointerstitium predominantly infiltrate the kidneys of RRP8-injected and TNP1-injected mice. Among CD3-positive cells in the glomerulus and tubulointerstitium, the proportions of CD4- and CD8-positive cells were similar.

Bottom Line: To obtain other autoantibodies associated with LN, we screened autoantigens reacting with the sera of LN patients by using an N-terminal biotinylated protein library created from a wheat cell-free protein production system.Both proteins are cationic, and their respective antibodies did not cross-react with dsDNA.These autoantibodies may be useful for prediction of LN in subsets of SLE patients who are negative for anti-dsDNA antibodies.

View Article: PubMed Central - PubMed

Affiliation: Department of Hematology, Clinical Immunology and Infectious Diseases, Ehime University Graduate School of Medicine, Ehime, Japan.

ABSTRACT
Systemic lupus erythematosus (SLE) is characterized by production of a variety of autoantibodies. Although anti-double-stranded DNA (anti-dsDNA) antibodies contribute to the pathogenesis of lupus nephritis (LN), they are not sufficient for diagnosis and evaluation of disease activity. To obtain other autoantibodies associated with LN, we screened autoantigens reacting with the sera of LN patients by using an N-terminal biotinylated protein library created from a wheat cell-free protein production system. We screened 17 proteins that showed higher positive signals in the active phase than in the inactive phase of SLE, and higher positive signals in the serum of SLE patient with nephritis than in that of patient without nephritis. Of these, two LN-associated autoantigens, ribosomal RNA-processing protein 8 (RRP8) and spermatid nuclear transition protein 1 (TNP1) were identified by immunoprecipitation and immunofluorescence of renal tissues. Circulating anti-RRP8 and anti-TNP1 autoantibodies were recognized and deposited as an immune complex (IC) in glomeruli. IC was deposited preferentially in glomeruli rather than in other organs in C57BL/6 mice injected with RRP8 or TNP1. ELISA analysis of sera from patients with various rheumatic diseases demonstrated reactivity for RRP8 and TNP1 in 20% and 14.7% of SLE patients, respectively, whereas there was little or no reactivity in patients with other rheumatic diseases. Among SLE patients, 63.6% and 45.5% of those with LN were positive for anti-RRP8 and anti-TNP1 antibodies, compared with 12.5% and 9.4% of SLE patients without nephritis, respectively. Both proteins are cationic, and their respective antibodies did not cross-react with dsDNA. These proteins released from apoptotic cells form ICs with each autoantibody, and their ICs may become trapped at anionic sites in the glomerular basement membrane, leading to deposition in glomeruli. These autoantibodies may be useful for prediction of LN in subsets of SLE patients who are negative for anti-dsDNA antibodies.

No MeSH data available.


Related in: MedlinePlus