The full scale of human miRNome in specific cell or tissue, especially in cancers, remains to be determined. An in-depth analysis of miRNomes in human normal liver, hepatitis liver, and hepatocellular carcinoma (HCC) was carried out in this study. We found nine miRNAs accounted for ∼88.2% of the miRNome in human liver. The third most highly expressed miR-199a/b-3p is consistently decreased in HCC, and its decrement significantly correlates with poor survival of HCC patients. Moreover, miR-199a/b-3p can target tumor-promoting PAK4 to suppress HCC growth through inhibiting PAK4/Raf/MEK/ERK pathway both in vitro and in vivo. Our study provides miRNomes of human liver and HCC and contributes to better understanding of the important deregulated miRNAs in HCC and liver diseases.

Intracellular nucleic acid sensors detect microbial RNA and DNA and trigger the production of type I interferon. However, the cytosolic nucleic acid-sensing system remains to be fully identified. Here we show that the cytosolic nucleic acid-binding protein LRRFIP1 contributed to the production of interferon-beta (IFN-beta) induced by vesicular stomatitis virus (VSV) and Listeria monocytogenes in macrophages. LRRFIP1 bound exogenous nucleic acids and increased the expression of IFN-beta induced by both double-stranded RNA and double-stranded DNA. LRRFIP1 interacted with beta-catenin and promoted the activation of beta-catenin, which increased IFN-beta expression by binding to the C-terminal domain of the transcription factor IRF3 and recruiting the acetyltransferase p300 to the IFN-beta enhanceosome via IRF3. Therefore, LRRFIP1 and its downstream partner beta-catenin constitute another coactivator pathway for IRF3-mediated production of type I interferon.

In hepatocellular carcinoma (HCC), biomarkers for prediction of prognosis and response to immunotherapy such as interferon-α (IFN-α) would be very useful in the clinic. We found that expression of retinoic acid-inducible gene-I (RIG-I), an IFN-stimulated gene, was significantly downregulated in human HCC tissues. Patients with low RIG-I expression had shorter survival and poorer response to IFN-α therapy, suggesting that RIG-I is a useful prognosis and IFN-α response predictor for HCC patients. Mechanistically, RIG-I enhances IFN-α response by amplifying IFN-α effector signaling via strengthening STAT1 activation. Furthermore, we found that RIG-I deficiency promotes HCC carcinogenesis and that hepatic RIG-I expression is lower in men than in women. RIG-I may therefore be a tumor suppressor in HCC and contribute to HCC gender disparity.

Calcium and its major downstream effector, calcium/calmodulin-dependent protein kinase II (CaMKII), are found to be important for the functions of immune cells. Lipopolysaccharide (LPS) has been shown to induce intracellular calcium release in macrophages; however, whether and how CaMKII is required for Toll-like receptor (TLR) signaling remain unknown. Here we demonstrate that TLR 4, 9, and 3 ligands markedly induce intracellular calcium fluxes and activate CaMKII-␣ in macrophages. Selective inhibition or RNA interference of CaMKII significantly suppresses TLR4, 9, 3-triggered production of interleukin-6 (IL-6), tumor necrosis factor-␣, and interferon-␣/␤ (IFN-␣/␤) in macrophages. Coincidently, overexpression of constitutively active CaMKII-␣ significantly enhances production of the above cytokines. In addition to the activation of mitogen-activated protein kinase and nuclear factor B pathways, CaMKII-␣ can directly bind and phosphorylate transforming growth factor ␤-activated kinase 1 (TAK1) and IFN regulatory factor 3 (IRF3; serine IntroductionOn recognition of pathogenic components, Toll-like receptors (TLRs) are activated, leading to a variety of signaling events that initiate innate immunity and activate immune cells to produce proinflammatory cytokines and type I interferon (IFN). 1,2 Most of the members of the TLR family, with the exception of TLR3, trigger immune response via the conserved myeloid differentiation factor 88 (MyD88)-dependent pathway, which involves MyD88, interleukin-1 (IL-1) receptor-associated kinase 1 (IRAK1), tumor necrosis factor (TNF) receptor-associated factor 6 (TRAF6), transforming growth factor-␤ (TGF-␤)-activated kinase 1 (TAK1), downstream mitogen-activated protein kinases (MAPKs), and nuclear factor B (NF-B). 2,3 Toll/IL-1 receptor-domain-containing adaptor protein inducing IFN-␤ (TRIF) has been found to induce the expression of type I IFN in response to TLR4 and TLR3 ligands, which associates with TANK-binding kinase 1 (TBK1) and activates downstream IFN regulatory factor 3 (IRF3). In addition, the TRIF pathway also contributes to TLR3-and TLR4-activated proinflammatory cytokine production. 3,4 TLR activation is essential for provoking the innate immune response and enhancing adaptive immunity against invading pathogens. Less efficient activation of the TLR response may not evoke potent anti-infection or antitumor immunity; however, excessive activation of TLR may also induce immunopathologic processes, such as endotoxin shock and autoimmune diseases. How to manipulate or control the TLR response for prevention and treatment of inflammatory and immunologic diseases largely depends on the understanding of the molecular basis for TLR responses. Up to now, molecular mechanisms for the initiation and regulation of TLR responses remain to be fully understood. In addition to the MyD88-or TRIF-dependent pathway, ligation of TLRs has been found to activate various other intracellular signaling molecules, such as phosphatidylinositol 3-kinase (PI3K)/ AKT 5 and MAPK kinase kinase (ME...