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Background@#Henoch-Schonlein purpura nephritis (HSPN) is a very common secondary kidney disease of childhood. Its pathogenesis and the treatment mechanism of glucocorticoid have not been fully elucidated. The aim of this study was to determine the relationship between p300 and the pathogenesis, glucocorticoid therapy in mice with HSPN, respectively.@*Methods@#Forty-eight C57BL/6N male mice, weighing 18 to 20 g, were selected (3–4 weeks old, n = 8 per group). The mice in the normal control group (Group I) were given normal solvent and the HSPN model group (Group II) were given sensitizing drugs. The mice in Group III were injected intraperitoneally with dexamethasone after being given sensitizing drugs. Meanwhile, mice in Groups IV, V and VI with conditional knockout of p300 were also given normal solvent, sensitizing drugs and dexamethasone. The levels of serum IgA, creatinine, and circulating immune complex (CIC) concentrations, 24 h urinary protein and urinary erythrocyte in C57 wild mice, and p300 conditional knockout mice in each group were measured. The expression of p300 in renal tissues and the expression of glucocorticoid receptor (GR) α and β, transforming growth factor (TGF)-β1, and activator protein (AP)-1 after dexamethasone treatment were determined by real-time polymerase chain reaction and Western blotting.@*Results@#Compared with the normal solvent control group (Group I), the expression of p300 mRNA in the model group (Group II) was significantly up-regulated. Western blotting further confirmed the result. Urinary erythrocyte count, 24 h urinary protein quantification, serum IgA, CIC, and renal pathologic score in Group V were distinctly decreased compared with non-knockout mice in Group II (9.7 ± 3.8 per high-power field [/HP] vs. 18.7 ± 6.2/HP, t = 1.828, P = 0.043; 0.18 ± 0.06 g/24 h vs. 0.36 ± 0.08 g/24 h, t = 1.837, P = 0.042; 18.78 ± 0.85 mg/mL vs. 38.46 ± 0.46 mg/mL, t = 1.925, P = 0.038; 0.80 ± 0.27 μg/mL vs. 1.64 ± 0.47 μg/mL, t = 1.892, P = 0.041; 7.0 ± 0.5 vs. 18.0 ± 0.5, t = 1.908, P = 0.039). Compared with non-knockout mice (Group III), the level of urinary erythrocyte count and serum IgA in knockout mice (Group VI) increased significantly after treatment with dexamethasone (3.7 ± 0.6/HP vs. 9.2 ± 3.5/HP, t = 2.186, P = 0.024; 12.38 ± 0.26 mg/mL vs. 27.85 ± 0.65 mg/mL, t = 1.852, P = 0.041). The expression level of GRα was considerably increased in the knockout group after dexamethasone treatment compared with non-knockout mice in mRNA and protein level (t = 2.085, P = 0.026; t = 1.928, P = 0.035), but there was no statistically significant difference in the expression level of GRβ between condition knockout and non-knockout mice (t = 0.059, P = 0.087; t = 0.038, P = 1.12). Furthermore, the expression levels of glucocorticoid resistance genes (AP-1 and TGF-β1) were notably increased after p300 knockout compared with non-knockout mice in mRNA and protein level (TGF-β1: t = 1.945, P = 0.034; t = 1.902, P = 0.039; AP-1: t = 1.914, P = 0.038; t = 1.802, P = 0.041).@*Conclusions@#p300 plays a crucial role in the pathogenesis of HSPN. p300 can down-regulate the expression of resistance genes (AP-1 and TGF-β1) by binding with GRα to prevent further renal injury and glucocorticoid resistance. Therefore, p300 is a promising new target in glucocorticoid therapy in HSPN.
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BACKGROUND@#Henoch-Schonlein purpura nephritis (HSPN) is a very common secondary kidney disease of childhood. Its pathogenesis and the treatment mechanism of glucocorticoid have not been fully elucidated. The aim of this study was to determine the relationship between p300 and the pathogenesis, glucocorticoid therapy in mice with HSPN, respectively.@*METHODS@#Forty-eight C57BL/6N male mice, weighing 18 to 20 g, were selected (3-4 weeks old, n = 8 per group). The mice in the normal control group (Group I) were given normal solvent and the HSPN model group (Group II) were given sensitizing drugs. The mice in Group III were injected intraperitoneally with dexamethasone after being given sensitizing drugs. Meanwhile, mice in Groups IV, V and VI with conditional knockout of p300 were also given normal solvent, sensitizing drugs and dexamethasone.The levels of serum IgA, creatinine, and circulating immune complex (CIC) concentrations, 24 h urinary protein and urinary erythrocyte in C57 wild mice, and p300 conditional knockout mice in each group were measured. The expression of p300 in renal tissues and the expression of glucocorticoid receptor (GR) α and β, transforming growth factor (TGF)-β1, and activator protein (AP)-1 after dexamethasone treatment were determined by real-time polymerase chain reaction and Western blotting.@*RESULTS@#Compared with the normal solvent control group (Group I), the expression of p300 mRNA in the model group (Group II) was significantly up-regulated. Western blotting further confirmed the result. Urinary erythrocyte count, 24 h urinary protein quantification, serum IgA, CIC, and renal pathologic score in Group V were distinctly decreased compared with non-knockout mice in Group II (9.7 ± 3.8 per high-power field [/HP] vs. 18.7 ± 6.2/HP, t = 1.828, P = 0.043; 0.18 ± 0.06 g/24 h vs. 0.36 ± 0.08 g/24 h, t = 1.837, P = 0.042; 18.78 ± 0.85 mg/mL vs. 38.46 ± 0.46 mg/mL, t = 1.925, P = 0.038; 0.80 ± 0.27 μg/mL vs. 1.64 ± 0.47 μg/mL, t = 1.892, P = 0.041; 7.0 ± 0.5 vs. 18.0 ± 0.5, t = 1.908, P = 0.039). Compared with non-knockout mice (Group III), the level of urinary erythrocyte count and serum IgA in knockout mice (Group VI) increased significantly after treatment with dexamethasone (3.7 ± 0.6/HP vs. 9.2 ± 3.5/HP, t = 2.186, P = 0.024; 12.38 ± 0.26 mg/mL vs. 27.85 ± 0.65 mg/mL, t = 1.852, P = 0.041). The expression level of GRα was considerably increased in the knockout group after dexamethasone treatment compared with non-knockout mice in mRNA and protein level (t = 2.085, P = 0.026; t = 1.928, P = 0.035), but there was no statistically significant difference in the expression level of GRβ between condition knockout and non-knockout mice (t = 0.059, P = 0.087; t = 0.038, P = 1.12). Furthermore, the expression levels of glucocorticoid resistance genes (AP-1 and TGF-β1) were notably increased after p300 knockout compared with non-knockout mice in mRNA and protein level (TGF-β1: t = 1.945, P = 0.034; t = 1.902, P = 0.039; AP-1: t = 1.914, P = 0.038; t = 1.802, P = 0.041).@*CONCLUSIONS@#p300 plays a crucial role in the pathogenesis of HSPN. p300 can down-regulate the expression of resistance genes (AP-1 and TGF-β1) by binding with GRα to prevent further renal injury and glucocorticoid resistance. Therefore, p300 is a promising new target in glucocorticoid therapy in HSPN.
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<p><b>OBJECTIVE</b>To study feasibility of Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2000) and British Isles Lupus Assessment Group 2004 (BILAG-2004) scoring systems for assessing renal disease activity in children with lupus nephritis (LN).</p><p><b>METHODS</b>The clinical data of 159 children with systemic lupus erythematosus (SLE) and LN were collected, and disease activity was assessed by SLEDAI-2000 and BILAG-2004 scoring systems. The correlations between SLEDAI-2000 and BILAG-2004 scores and 24-hour urinary protein excretion and renal pathology index were analyzed. The SLEDAI-2000 and BILAG-2004 scoring systems were evaluated using ROC curve.</p><p><b>RESULTS</b>Approximately one third (31.5%) of the 159 children had a moderate level of 24-hour urinary protein excretion. Among the 37 patients undergoing renal biopsy, 46.0% had diffuse LN (type Ⅳ). 24-hour urinary protein excretion was positively correlated with both SLEDAI-2000 (r=0.36, P<0.05) and BILAG-2004 scores (r= 0.39, P<0.05). Children with types Ⅰ, Ⅱ, Ⅲ, and Ⅳ LN had pathology activity index (AI) which positively correlated with SLEDAI-2000 scores (r=0.86, 0.88, 0.84, 0.77 respectively; P<0.05) and BILAG-2004 scores (r= 0.88, 0.98, 0.86, 0.89 respectively; P<0.05). SLEDAI-2000 score showed the best correlation with AI in patients with type Ⅱ LN, followed by those with type Ⅰ LN. BIILAG-2004 score showed the best correlation with AI in patients with type Ⅱ LN, followed by those with type Ⅳ LN. The BILAG-2004 scoring system had an area under the ROC curve (AUC) of 0.93, and the SLEDAI-2000 scoring system had an AUC of 0.88.</p><p><b>CONCLUSIONS</b>BILAG-2004 and SLEDAI-2000 scoring systems can be used to assess renal disease activity of patients with LN. The BILAG-2004 scoring system can provide more reliable and comprehensive assessment.</p>