The hTERT-p50 homodimer inhibits PLEKHA7 expression to promote gastric cancer invasion and metastasis.

Although accumulating evidence has highlighted the molecular mechanisms by which hTERT promotes tumour cell invasion and metastasis, the molecular mechanisms of the properties enabling hTERT to contribute to invasion and metastasis have not been clearly illustrated. Here, we report that hTERT promotes gastric cancer invasion and metastasis by recruiting p50 to synergistically inhibit PLEKHA7 expression. We observed that the expression of PLEKHA7 in gastric cancer was significantly negatively associated with the TNM stage and lymphatic metastasis and that decreased PLEKHA7 expression dramatically increased invasion and metastasis in gastric cancer cells. Further mechanistic research showed that hTERT directly regulates PLEKHA7 expression by binding p50 and recruiting the hTERT/p50 complex to the PLEKHA7 promoter. Increased hTERT dramatically decreased PLEKHA7 expression and promoted invasion and metastasis in gastric cancer cells. The hTERT-mediated invasion/metastasis properties at least partially depended on PLEKHA7. Our work uncovers a novel molecular mechanism underlying invasion/metastasis in gastric cancer orchestrated by hTERT and p50.

Knockout of cytochrome P450 1A1 enhances lipopolysaccharide-induced acute lung injury in mice by targeting NF-κB activation.

Acute lung injury (ALI) is accompanied by overactivation of multiple pro-inflammatory factors. Cytochrome P450 1A1 (CYP1A1) has been shown to aggravate lung injury in response to hyperoxia. However, the relationship between CYP1A1 and lipopolysaccharide (LPS)-induced ALI is unknown. In this study, CYP1A1 was shown to be upregulated in mouse lung in response to LPS. Using CYP1A1-deficient (CYP1A1-/-) mice, we found that CYP1A1 knockout enhanced LPS-induced ALI, as evidenced by increased TNF-α, IL-1ß, IL-6, and nitric oxide in lung; these effects were mediated by overactivation of NF-κB and iNOS. Furthermore, we found that aspartate aminotransferase, lactate dehydrogenase, creatine kinase, and creatinine levels were elevated in serum of LPS-induced CYP1A1-/- mice. Altogether, these data provide novel insights into the involvement of CYP1A1 in LPS-induced lung injury.

Cytochrome P450 1A1 enhances inflammatory responses and impedes phagocytosis of bacteria in macrophages during sepsis.

The hydroxylase cytochrome P450 1A1 (CYP1A1) is regulated by the inflammation-limiting aryl hydrocarbon receptor (AhR), but CYP1A1 immune functions remain unclear. We observed CYP1A1 overexpression in peritoneal macrophages (PMs) isolated from mice following LPS or heat-killed Escherichia. coli (E. coli) challenge. CYP1A1 overexpression augmented TNF-α and IL-6 production in RAW264.7 cells (RAW) by enhancing JNK/AP-1 signalling. CYP1A1 overexpression also promoted 12S-hydroxy-5Z,8Z,10E,14Z-eicosatetraenoic acid (12(S)-HETE) production in activated RAW, while a 12(S)-HETE antibody attenuated and 12(S)-HETE alone induced inflammatory responses. Macrophages harbouring hydroxylase-deficient CYP1A1 demonstrated reduced 12(S)-HETE generation and LPS-induced TNF-α/IL-6 secretion. CYP1A1 overexpression also impaired phagocytosis of bacteria via decreasing the expression of scavenger receptor A (SR-A) in PMs. Mice injected with CYP1A1-overexpressing PMs were more susceptible to CLP- or E. coli-induced mortality and bacteria invading, while Rhapontigenin, a selective CYP1A1 inhibitor, improved survival and bacteria clearance of mice in sepsis. CYP1A1 and 12(S)-HETE were also elevated in monocytes and plasma of septic patients and positively correlated with SOFA scores. Macrophage CYP1A1 disruption could be a promising strategy for treating sepsis. Video abstract.

Correction to: Cytochrome P450 1A1 enhances inflammatory responses and impedes phagocytosis of bacteria in macrophages during sepsis.

An amendment to this paper has been published and can be accessed via the original article.

Neutrophilic granule protein (NGP) attenuates lipopolysaccharide-induced inflammatory responses and enhances phagocytosis of bacteria by macrophages.

Neutrophilic granule protein (NGP) belongs to the cystatin superfamily. Even though this superfamily is critically involved in cancer biology and adaptive immunity, the relationship of macrophage NGP to inflammation and phagocytosis remains poorly understood. In this study, we observed a significant increase of NGP in peritoneal macrophages (PMs) isolated from mice challenged with E. coli or lipopolysaccharide (LPS), as judged by NGP mRNA microarray. We also found changes in NGP to be mainly Toll-like receptor 4 (TLR4)-dependent. By western blot and electrophoretic mobility shift assay, we demonstrated NGP overexpression to reduce TNF-α and IL-1ß production by LPS-induced RAW264.7 cells (RAW) via suppression of the NF-κB (p65 and p50) signalling pathway, rather than the JNK1/AP-1 (fos and jun) signalling pathway. NGP overexpression by LPS-induced RAW also induced IL-10, an anti-inflammatory cytokine, which was partially involved in the anti-inflammatory effect produced by NGP overexpression. Moreover, upregulated NGP enhanced the phagocytosis of E. coli by RAW. Taken together, these results demonstrated NGP to be an important host defense component that regulates inflammatory responses and phagocytosis by activated macrophages. As such, NGP may be useful for the treatment of inflammatory based disease.

Cytochrome P450 1A1 enhances Arginase-1 expression, which reduces LPS-induced mouse peritonitis by targeting JAK1/STAT6.

The polarization of macrophages is critical to inflammation and tissue repair, with unbalanced macrophage polarization associated with critical dysfunctions of the immune system. Cytochrome P450 1A1 (CYP1A1) is a hydroxylase mainly controlled by the inflammation-limiting aryl hydrocarbon receptor (AhR), which plays a critical role in mycoplasma infection, oxidative stress injury, and cancer. Arginase-1 (Arg-1) is a surrogate for polarized alternative macrophages and is important to the production of nitric oxide (NO) by the modulation of arginine. In the present study, we found CYP1A1 to be upregulated in IL-4-stimulated mouse peritoneal macrophages (PMs) and human peripheral blood monocytes. Using CYP1A1-overexpressing RAW264.7 cells (CYP1A1/RAW) we found that CYP1A1 augmented Arg-1 expression by strengthening the activation of the JAK1/STAT6 signaling pathway in macrophages treated with IL-4. 15(S)-HETE, a metabolite of CYP1A1 hydroxylase, was elevated in IL-4-induced CYP1A1/RAW cells. Further, in macrophages, the loss-of-CYP1A1-hydroxylase activity was associated with reduced IL-4-induced Arg-1 expression due to impaired 15(S)-HETE generation. Of importance, CYP1A1 overexpressing macrophages reduced the inflammation associated with LPS-induced peritonitis. Taken together, these findings identified a novel signaling axis, CYP1A1-15(S)-HETE-JAK1-STAT6, that may be a promising target for the proper maintenance of macrophage polarization and may also be a means by which to treat immune-related disease due to macrophage dysfunction.

Ellipticine Conveys Protective Effects to Lipopolysaccharide-Activated Macrophages by Targeting the JNK/AP-1 Signaling Pathway.

Ellipticine, a natural product from Ochrosia elliptica, has been broadly investigated for its anticancer effects. Although inflammation has been clearly identified as a key factor in the onset and progression of cancer, the relationship between ellipticine and inflammation remains unknown. Hence, the aims of the present study were to assess the effects of ellipticine on the inflammatory responses to lipopolysaccharide (LPS)-induced macrophages and to potentially identify the underlying mechanisms involved. Viability testing showed that ellipticine was not significantly toxic to Raw264.7 cells and actually conveyed protective effects to LPS-stimulated Raw264.7 cells and human peripheral blood monocytes by decreasing the secretion of inflammatory factors (TNF-α and IL-6). The results of western blot analysis and electrophoretic mobility shift assays showed that ellipticine markedly suppressed LPS-induced activation of the JNK/AP-1 (c-Fos and c-Jun) signaling pathway, but not ERK/p38/NF-κB pathway (p65 and p50) activation. Furthermore, ellipticine reduced the inflammatory response and mortality in a mouse model of LPS-induced endotoxic shock. Collectively, these data indicate that ellipticine may be a potential therapeutic agent for the treatment of inflammation-associated diseases.

Early prevention of trauma-related infection/sepsis.

Trauma still represents one of the major causes of death worldwide. Despite the reduction of post-traumatic sepsis over the past two decades, the mortality of septic trauma inpatients is still high (19.5-23 %). Early prevention of sepsis development can aid in the subsequent treatment of patients and help improve their outcomes. To date, the prevention of trauma-related infection/sepsis has mainly included infection prevention (e.g., surgical management, prophylactic antibiotics, tetanus vaccination, immunomodulatory interventions) and organ dysfunction prevention (e.g., pharmaceuticals, temporary intravascular shunts, lung-protective strategies, enteral immunonutrition, acupuncture). Overall, more efficient ways should be developed to prevent trauma-related infection/sepsis.