Cell level inflammatory signalling is a combination of initiation at cell membrane receptors and modulation by cytoplasmic regulatory proteins. For keratinocytes, the predominant cell type in the epidermis, this would include toll-like receptors (TLR) and cytoplasmic proteins that propagate or dampen post-receptor signalling. We previously reported that increased levels of tumor necrosis factor α induced protein 3-interacting protein 1 (TNIP1) in HaCaT keratinocytes leads to decreased expression of stress response and inflammation-associated genes. This finding suggested decreased TNIP1 levels, as seen in some cutaneous disease states, may produce the opposite effect, sensitizing cells to triggers of inflammatory signalling including those sensed by TLR. In this study of TNIP1-deficient HaCaT keratinocytes we examined intracellular signalling consequences especially those expected to produce gene expression changes downstream of TLR3 or TLR2/6 activation by Poly (I:C) or FSL-1, agonists modeling skin relevant pathogens. We found TNIP1-deficient keratinocytes are hyper-sensitive to TLR activation compared to control cells with a normal complement of TNIP1 and receiving the same agonist stimulation. TNIP1-deficient keratinocytes have increased levels of activated (phosphorylated) cytoplasmic mediators such as JNK and p38 and greater nuclear translocation of NF-κB and phospho-p38 when exposed to TLR ligands. This is consistent with significantly increased expression of several inflammatory cytokines and chemokines, such as IL-6 and IL-8. These results describe how decreased TNIP1 levels promote a hyper-sensitive state in HaCaT keratinocytes evidenced by increased activation of signalling molecules downstream of TLR agonists and increased expression of pro-inflammatory mediators. TNIP1 keratinocyte deficiency as reported for some skin diseases may predispose these cells to excessive inflammatory signalling upon exposure to viral or bacterial ligands for TLR.

细胞水平的炎症信号是细胞膜受体起始和细胞质调节蛋白调节的结合。对于角质形成细胞（表皮中的主要细胞类型），这将包括通行费样受体（TLR）和细胞质蛋白，这些蛋白会传播或抑制受体后的信号传导。我们以前曾报道，HaCaT角质形成细胞中肿瘤坏死因子α诱导的蛋白3-相互作用蛋白1（TNIP1）的水平升高导致应激反应和炎症相关基因的表达降低。这一发现表明，在某些皮肤病状态下，TNIP1水平降低可能产生相反的作用，使细胞对炎症信号的触发敏感，包括通过TLR感应的信号。在这项对TNIP1缺失的HaCaT角质形成细胞的研究中，我们研究了细胞内信号转导的后果，特别是那些预期会通过Poly（I：C）或FSL-1（建模皮肤相关病原体的激动剂）在TLR3或TLR2 / 6激活下游产生基因表达变化的后果。我们发现，与具有正常TNIP1补体并接受相同激动剂刺激的对照细胞相比，缺乏TNIP1的角质形成细胞对TLR激活高度敏感。缺乏TNIP1的角质形成细胞具有较高水平的活化（磷酸化）细胞质介质，例如JNK和p38，并且在暴露于TLR配体时具有更大的NF-κB和磷酸化p38核移位。这与几种炎性细胞因子和趋化因子例如IL-6和IL-8的表达显着增加是一致的。这些结果描述了降低的TNIP1水平如何在HaCaT角质形成细胞中促进超敏状态，这可通过TLR激动剂下游的信号分子激活增强和促炎性介质表达增加来证明。据某些皮肤病报道，TNIP1角质形成细胞缺乏症可能使这些细胞在暴露于TLR的病毒或细菌配体后易发炎性信号。