Tamm-Horsfall glycoprotein links innate immune cell activation with adaptive immunity via a Toll-like receptor-4–dependent mechanism
Marcus D. Säemann, Thomas Weichhart, Maximilian Zeyda, Günther Staffler, Michael Schunn, Karl M. Stuhlmeier, Yuri Sobanov, Thomas M. Stulnig, Shizuo Akira, Alexander von Gabain, Uwe von Ahsen, Walter H. Hörl, Gerhard J. Zlabinger
Marcus D. Säemann, Thomas Weichhart, Maximilian Zeyda, Günther Staffler, Michael Schunn, Karl M. Stuhlmeier, Yuri Sobanov, Thomas M. Stulnig, Shizuo Akira, Alexander von Gabain, Uwe von Ahsen, Walter H. Hörl, Gerhard J. Zlabinger
View: Text | PDF
Article Immunology

Tamm-Horsfall glycoprotein links innate immune cell activation with adaptive immunity via a Toll-like receptor-4–dependent mechanism

Abstract

Tamm-Horsfall glycoprotein (THP) is expressed exclusively in the kidney and constitutes the most abundant protein in mammalian urine. A critical role for THP in antibacterial host defense and inflammatory disorders of the urogenital tract has been suggested. We demonstrate that THP activates myeloid DCs via Toll-like receptor-4 (TLR4) to acquire a fully mature DC phenotype. THP triggers typical TLR signaling, culminating in activation of NF-κB. Bone marrow–derived macrophages from TLR4- and MyD88-deficient mice were nonresponsive to THP in contrast to those from TLR2- and TLR9-deficient mice. In vivo THP-driven TNF-α production was evident in WT but not in Tlr4–/– mice. Importantly, generation of THP-specific Abs consistently detectable in urinary tract inflammation was completely blunted in Tlr4–/– mice. These data show that THP is a regulatory factor of innate and adaptive immunity and therefore could have significant impact on host immunity in the urinary tract.

Authors

Marcus D. Säemann, Thomas Weichhart, Maximilian Zeyda, Günther Staffler, Michael Schunn, Karl M. Stuhlmeier, Yuri Sobanov, Thomas M. Stulnig, Shizuo Akira, Alexander von Gabain, Uwe von Ahsen, Walter H. Hörl, Gerhard J. Zlabinger

×

Figure 4

Options: View larger image (or click on image) Download as PowerPoint
Immunostimulatory effects of THP are dependent on p38-, ERK-1/2–MAPK kin...
Immunostimulatory effects of THP are dependent on p38-, ERK-1/2–MAPK kinase and NF-κB signaling. Immature human DCs (A) or murine macrophages (B) were incubated with THP, LPS, or medium. Subsequently, phospho-p38 (p-p38) and phospho–ERK-1/2 (p-ERK) were determined by immunoblotting; p38 and ERK-2, respectively, were detected from stripped membranes. Blots are representative of 4 independent experiments. (C) Immature DCs were incubated with THP, LPS, or medium, and phospho-Akt (p-Akt) as well as total Akt were determined from whole cell lysates by immunoblotting. Data are representative of 3 independent experiments. (D) Immature human DCs preincubated with or without the indicated MAPK inhibitors were exposed to THP, LPS, or medium. Cell-free supernatants were collected after 18 hours and were analyzed for TNF-α by ELISA. Data are expressed as mean ± SEM of 4 different donor combinations. *Significantly different from the values for stimulated control; P < 0.05. (E) Immature DCs were incubated with THP, LPS, or medium, and immunoblotting was performed from whole-cell lysates using Abs against IκB-α and ERK-2. (F) THP, LPS, or medium was added to immature human DCs. Oligonucleotides labeled with 32P, containing a NF-κB consensus sequence, were incubated with nuclear extracts followed by nondenaturing gel electrophoresis. Similar results were obtained in 2 independent experiments. (G) Immature human DCs preincubated with or without the NF-κB inhibitor SN50 were exposed to THP, LPS, or medium. Cell-free supernatants were collected after 18 hours and were analyzed for cytokines by ELISA. Data are representative of 4 independent experiments. *Significantly different from the values for stimulated control; P < 0.05.