Objective To use genetic variants as unconfounded proxies of C reactive protein concentration to study its causal role in coronary heart disease. Design Mendelian randomisation meta-analysis of individual participant data from 47 epidemiological studies in 15 countries. Participants 194 418 participants, including 46 557 patients with prevalent or incident coronary heart disease. Information was available on four CRP gene tagging single nucleotide polymorphisms (rs3093077, rs1205, rs1130864, rs1800947), concentration of C reactive protein, and levels of other risk factors. Main outcome measures Risk ratios for coronary heart disease associated with genetically raised C reactive protein versus risk ratios with equivalent differences in C reactive protein concentration itself, adjusted for conventional risk factors and variability in risk factor levels within individuals. Results CRP variants were each associated with up to 30% per allele difference in concentration of C reactive protein (P<10 −34) and were unrelated to other risk factors. Risk ratios for coronary heart disease per additional copy of an allele associated with raised C reactive protein were 0.93 (95% confidence interval 0.87 to 1.00) for rs3093077; 1.00 (0.98 to 1.02) for rs1205; 0.98 (0.96 to 1.00) for rs1130864; and 0.99 (0.94 to 1.03) for rs1800947. In a combined analysis, the risk ratio for coronary heart disease was 1.00 (0.90 to 1.13) per 1 SD higher genetically raised natural log (ln) concentration of C reactive protein. The genetic findings were discordant with the risk ratio observed for coronary heart disease of 1.33 (1.23 to 1.43) per 1 SD higher circulating ln concentration of C reactive protein in prospective studies (P=0.001 for difference). Conclusion Human genetic data indicate that C reactive protein concentration itself is unlikely to be even a modest causal factor in coronary heart disease.

Macrophages that differentiate from precursor monocytes can be polarized into a classically activated (M1) or alternatively activated (M2) status depending on different stimuli. Generally, interferon (IFN)-γ and lipopolysaccharide (LPS) are considered the classical stimuli with which to establish M1 polarization. IFN regulatory factor (IRF)1 and IFN-β are two crucial molecules involved in IFN-γ- and LPS-initialed signaling. However, the association between IRF1 and IFN-β in the context of the M1 polarization of macrophages is not yet fully understood. In this study, we demonstrate that U937-derived macrophages, in response to IFN-γ and LPS stimulation, readily acquire an M1 status, indicated by the increased expression of interleukin (IL)-12, IL-6, IL-23, tumor necrosis factor (TNF)-α and the M1-specific cell surface antigen, CD86, and the decreased expression of the M2-specific mannose receptor, CD206. However, the knockdown of IRF1 in U937-derived macrophages led to an impaired M1 status, as indicated by the decreased expression of the above-mentioned M1 markers, and the increased expression of the M2 markers, CD206 and IL-10. A similar phenomenon was observed in the M1 macrophages in which IFN-β was inhibited. Furthermore, we demonstrated that IRF1 and IFN-β may interact with each other in the IFN-γ- and LPS-initiated signaling pathway, and contribute to the IRF5 regulation of M1 macrophages. In addition, the conditioned medium collected from the M1 macrophages in which IRF1 or IFN-β were inhibited, exerted pro-tumor effects on the HepG2 and SMMC-7721 cells, as indicated by an increase in proliferation, the inhibition of apoptosis and an enhanced invasion capability. The findings of our study suggest that the interactions of IRF1, IFN-β and IRF5 are involved in the M1 polarization of macro phages and have antitumor functions. These data may provide a novel antitumor strategy for targeted cancer therapy.

Hepatocellular carcinoma is the third most common cause of cancer death worldwide. Novel early detection biomarkers and efficacious therapy strategies are needed. Macrophages recruited from circulation monocytes are the major component of solid cancer and play an important role in the carcinogenesis. Whether overexpression of L-12 in monocytes could induce the phenotype directional differentiation into tumoricidal M1 macrophages and inhibit HCC growth in tumor microenvironment was investigated in this study. For the establishment of the monocyte/IL-12 and polarization of M1-like macrophage, the IL-12 overexpressing recombinant monocyte/IL-12 cells were established by infecting with pAd5F35-CMV/IL-12 adenovirus and co-cultured with HCC SMMC-7721 and Hep3B cells. It was found that the phenotype of monocyte/IL-12 polarized to M1-like macrophages with CD197high IL-12high CD206low IL-10low, and decreased expression of TGF-β, VEGF-A, and MMP-9. In order to explore the mechanism underlying the macrophages polarization, we detected the Stat-3 pathway and its downstream transcription factor c-myc, and found that the p-Stat-3 and c-myc were down-regulated. To evaluate the effects of monocyte/IL-12 on inhibiting HCC growth, various assays including CCK8, flow cytometry, colony-forming and Transwell assays in vitro, and xenograft mouse models and immunohistochemical analyses in vivo were used to detect the HCC growth and relative markers. Treated with IL-12 overexpressing monocytes, the xenograft tumor growth was significantly inhibited in vivo. These results have proven that IL-12-overexpressed monocytes could directionally differentiate to M1-like macrophages through downregulation of Stat-3 and result in the inhibition of HCC growth.

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