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TLR-mediated albuminuria needs TNF α -mediated cooperativity between TLRs present in hematopoietic tissues and CD80 present on non-hematopoietic tissues in mice

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ABSTRACT

Transient albuminuria induced by pathogen-associated molecular patterns (PAMPs) in mice through engagement of Toll-like receptors (TLRs) is widely studied as a partial model for some forms of human nephrotic syndrome (NS). In addition to TLRs, CD80 has been shown to be essential for PAMP-mediated albuminuria. However, the mechanistic relationships between TLRs, CD80 and albuminuria remain unclear. Here, we show that albuminuria and CD80-uria induced in mice by many TLR ligands are dependent on the expression of TLRs and their downstream signalling intermediate MyD88 exclusively in hematopoietic cells and, conversely, on CD80 expression exclusively in non-hematopoietic cells. TNFα is crucial for TLR-mediated albuminuria and CD80-uria, and induces CD80 expression in cultured renal podocytes. IL-10 from hematopoietic cells ameliorates TNFα production, albuminuria and CD80-uria but does not prevent TNFα-mediated induction of podocyte CD80 expression. Chitohexaose, a small molecule originally of parasite origin, mediates TLR4-dependent anti-inflammatory responses, and blocks TLR-mediated albuminuria and CD80-uria through IL-10. Thus, TNFα is a prominent mediator of renal CD80 induction and resultant albuminuria in this model, and small molecules modulating TLR-mediated inflammatory activation might have contributory or adjunct therapeutic potential in some contexts of NS development.

No MeSH data available.


Chitohexaose blocks TLR-mediated TNFα induction through IL-10. (A) Comparison of urinary albumin:creatinine ratios in B6 and IL-10−/− mice given 1 μg of LPS, 10 μg of p(I:C) or PBS (five mice per group). (B) Comparison of urinary CD80 levels in B6 and IL-10−/− mice receiving 1 μg of LPS or PBS (six mice per group). (C) Comparison of urinary albumin:creatinine ratios in IL-10−/− mice given PBS, 1 μg of LPS without or with 250 μg chitohexaose (five mice per group). (D) Comparison of urinary CD80 levels in IL-10−/− mice given PBS, 1 μg of LPS without or with 250 μg of chitohexaose (five mice per group). (E) Relative CD80 mRNA expression levels in E11 podocytes that had been exposed to PBS (CTRL), TNFα alone (1 ng/ml), IL-10 alone (50 ng/ml) or in combination (n=6, three independent experiments). Data represent mean±s.e.m. ND, not detectable; ns, not significant.
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DMM023440F7: Chitohexaose blocks TLR-mediated TNFα induction through IL-10. (A) Comparison of urinary albumin:creatinine ratios in B6 and IL-10−/− mice given 1 μg of LPS, 10 μg of p(I:C) or PBS (five mice per group). (B) Comparison of urinary CD80 levels in B6 and IL-10−/− mice receiving 1 μg of LPS or PBS (six mice per group). (C) Comparison of urinary albumin:creatinine ratios in IL-10−/− mice given PBS, 1 μg of LPS without or with 250 μg chitohexaose (five mice per group). (D) Comparison of urinary CD80 levels in IL-10−/− mice given PBS, 1 μg of LPS without or with 250 μg of chitohexaose (five mice per group). (E) Relative CD80 mRNA expression levels in E11 podocytes that had been exposed to PBS (CTRL), TNFα alone (1 ng/ml), IL-10 alone (50 ng/ml) or in combination (n=6, three independent experiments). Data represent mean±s.e.m. ND, not detectable; ns, not significant.

Mentions: Because chitohexaose enhanced IL-10 levels in LPS-treated mice, we examined whether chitohexaose-mediated inhibition of albuminuria was IL-10 dependent. IL-10−/− mice were hyper-responsive to induction of TLR-mediated CD80-uria and albuminuria, and lower doses of LPS and poly(I:C) were used for the experiments. At these doses, IL-10−/− mice showed a higher albumin:creatinine ratio as compared to that upon PBS injection (Fig. 7A). Ratios in B6 mice were not significantly different from those in controls (Fig. 7A). At this lower dose, IL-10−/− mice also showed CD80-uria (Fig. 7B) that was significantly more severe than that seen in B6 mice at this dose. Notably, chitohexaose could not block the enhancement in the albumin:creatinine ratio (Fig. 7C) or CD80-uria (Fig. 7D) in IL-10−/− mice unlike in B6 mice (Fig. 6A,B), indicating that the effects of chitohexaose are mediated through IL-10 rather than being independent of IL-10. IL-10 could not block TNFα-mediated CD80 mRNA induction in E11 podocyte cells (Fig. 7E), suggesting that IL-10 might be acting by decreasing TNFα production in vivo.Fig. 7.


TLR-mediated albuminuria needs TNF α -mediated cooperativity between TLRs present in hematopoietic tissues and CD80 present on non-hematopoietic tissues in mice
Chitohexaose blocks TLR-mediated TNFα induction through IL-10. (A) Comparison of urinary albumin:creatinine ratios in B6 and IL-10−/− mice given 1 μg of LPS, 10 μg of p(I:C) or PBS (five mice per group). (B) Comparison of urinary CD80 levels in B6 and IL-10−/− mice receiving 1 μg of LPS or PBS (six mice per group). (C) Comparison of urinary albumin:creatinine ratios in IL-10−/− mice given PBS, 1 μg of LPS without or with 250 μg chitohexaose (five mice per group). (D) Comparison of urinary CD80 levels in IL-10−/− mice given PBS, 1 μg of LPS without or with 250 μg of chitohexaose (five mice per group). (E) Relative CD80 mRNA expression levels in E11 podocytes that had been exposed to PBS (CTRL), TNFα alone (1 ng/ml), IL-10 alone (50 ng/ml) or in combination (n=6, three independent experiments). Data represent mean±s.e.m. ND, not detectable; ns, not significant.
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DMM023440F7: Chitohexaose blocks TLR-mediated TNFα induction through IL-10. (A) Comparison of urinary albumin:creatinine ratios in B6 and IL-10−/− mice given 1 μg of LPS, 10 μg of p(I:C) or PBS (five mice per group). (B) Comparison of urinary CD80 levels in B6 and IL-10−/− mice receiving 1 μg of LPS or PBS (six mice per group). (C) Comparison of urinary albumin:creatinine ratios in IL-10−/− mice given PBS, 1 μg of LPS without or with 250 μg chitohexaose (five mice per group). (D) Comparison of urinary CD80 levels in IL-10−/− mice given PBS, 1 μg of LPS without or with 250 μg of chitohexaose (five mice per group). (E) Relative CD80 mRNA expression levels in E11 podocytes that had been exposed to PBS (CTRL), TNFα alone (1 ng/ml), IL-10 alone (50 ng/ml) or in combination (n=6, three independent experiments). Data represent mean±s.e.m. ND, not detectable; ns, not significant.
Mentions: Because chitohexaose enhanced IL-10 levels in LPS-treated mice, we examined whether chitohexaose-mediated inhibition of albuminuria was IL-10 dependent. IL-10−/− mice were hyper-responsive to induction of TLR-mediated CD80-uria and albuminuria, and lower doses of LPS and poly(I:C) were used for the experiments. At these doses, IL-10−/− mice showed a higher albumin:creatinine ratio as compared to that upon PBS injection (Fig. 7A). Ratios in B6 mice were not significantly different from those in controls (Fig. 7A). At this lower dose, IL-10−/− mice also showed CD80-uria (Fig. 7B) that was significantly more severe than that seen in B6 mice at this dose. Notably, chitohexaose could not block the enhancement in the albumin:creatinine ratio (Fig. 7C) or CD80-uria (Fig. 7D) in IL-10−/− mice unlike in B6 mice (Fig. 6A,B), indicating that the effects of chitohexaose are mediated through IL-10 rather than being independent of IL-10. IL-10 could not block TNFα-mediated CD80 mRNA induction in E11 podocyte cells (Fig. 7E), suggesting that IL-10 might be acting by decreasing TNFα production in vivo.Fig. 7.

View Article: PubMed Central - PubMed

ABSTRACT

Transient albuminuria induced by pathogen-associated molecular patterns (PAMPs) in mice through engagement of Toll-like receptors (TLRs) is widely studied as a partial model for some forms of human nephrotic syndrome (NS). In addition to TLRs, CD80 has been shown to be essential for PAMP-mediated albuminuria. However, the mechanistic relationships between TLRs, CD80 and albuminuria remain unclear. Here, we show that albuminuria and CD80-uria induced in mice by many TLR ligands are dependent on the expression of TLRs and their downstream signalling intermediate MyD88 exclusively in hematopoietic cells and, conversely, on CD80 expression exclusively in non-hematopoietic cells. TNFα is crucial for TLR-mediated albuminuria and CD80-uria, and induces CD80 expression in cultured renal podocytes. IL-10 from hematopoietic cells ameliorates TNFα production, albuminuria and CD80-uria but does not prevent TNFα-mediated induction of podocyte CD80 expression. Chitohexaose, a small molecule originally of parasite origin, mediates TLR4-dependent anti-inflammatory responses, and blocks TLR-mediated albuminuria and CD80-uria through IL-10. Thus, TNFα is a prominent mediator of renal CD80 induction and resultant albuminuria in this model, and small molecules modulating TLR-mediated inflammatory activation might have contributory or adjunct therapeutic potential in some contexts of NS development.

No MeSH data available.