Toll like receptors (TLRs) represent members of the pattern recognition receptors and are responsible for discriminating self from non-self. In the human body, this function is executed by 11 specialized receptors present on the cell surface or in endosomal compartments of immune cells. These potent receptors, which induce secretion of inflammatory and anti-viral cytokines, need tight regulation to protect the host against systemic effects.
The LPS sensing TLR4 is present on the cell surface and in phagosomes of immune cells. ZFYVE27 is a membrane protein localized in the tubular endoplasmic reticulum required for protrusion outgrowth during neurite formation in neuronal cells. Preliminary data from our research group suggested an effect of the vesicle transport protein ZFYVE27 on TLR4-mediated signaling. ZFYVE27 silencing was shown to impair TLR4-mediated signaling in human macrophages and macrophage-like THP-1 cells.
In this study we have narrowed down the effect of ZFYVE27 silencing on TLR4-mediated signaling to intracellular TLR4 signaling and examined a possible effect of ZFYVE27 on phagocytosis of Gram-negative bacteria. ZFYVE27 knockout cell lines were generated and tested in their LPS response to optimize the experimental conditions and generate a model cell line to expand the insight into the function of different protein domains of ZFYVE27. Moreover, pilot experiments on intracellular TLRs suggested a more general effect of ZFYVE27 on TLRs signaling. ZFYVE27 silencing prolonged TLR8- and TLR9-mediated signaling (endosomal TLRs), and these results should be confirmed and examined further.
Detailed insight into the regulation network of TLRs can reveal additional targets for treatment strategies of different types of cancers, autoimmune and inflammatory disorders.