GPR43 regulates HBV X protein (HBx)-induced inflammatory response in human LO2 hepatocytes

Short-chain fatty acids in cancer pathogenesis

Cancer is a multi-step process that can be viewed as a cellular and immunological shift away from homeostasis in response to selected infectious agents, mutations, diet, and environmental carcinogens. Homeostasis, which contributes importantly to the definition of "health," is maintained, in part by the production of short-chain fatty acids (SCFAs), which are metabolites of specific gut bacteria. Alteration in the composition of gut bacteria, or dysbiosis, is often a major risk factor for some two dozen tumor types. Dysbiosis is often characterized by diminished levels of SCFAs in the stool, and the presence of a "leaky gut," permitting the penetration of microbes and microbial derived molecules (e.g., lipopolysaccharides) through the gut wall, thereby triggering chronic inflammation. SCFAs attenuate inflammation by inhibiting the activation of nuclear factor kappa B, by decreasing the expression of pro-inflammatory cytokines such as tumor necrosis factor alpha, by stimulating the expression of anti-inflammatory cytokines such as interleukin-10 and transforming growth factor beta, and by promoting the differentiation of naïve T cells into T regulatory cells, which down-regulate immune responses by immunomodulation. SCFA function epigenetically by inhibiting selected histone acetyltransferases that alter the expression of multiple genes and the activity of many signaling pathways (e.g., Wnt, Hedgehog, Hippo, and Notch) that contribute to the pathogenesis of cancer. SCFAs block cancer stem cell proliferation, thereby potentially delaying or inhibiting cancer development or relapse by targeting genes and pathways that are mutated in tumors (e.g., epidermal growth factor receptor, hepatocyte growth factor, and MET) and by promoting the expression of tumor suppressors (e.g., by up-regulating PTEN and p53). When administered properly, SCFAs have many advantages compared to probiotic bacteria and fecal transplants. In carcinogenesis, SCFAs are toxic against tumor cells but not to surrounding tissue due to differences in their metabolic fate. Multiple hallmarks of cancer are also targets of SCFAs. These data suggest that SCFAs may re-establish homeostasis without overt toxicity and either delay or prevent the development of various tumor types.

HBx induced upregulation of FATP2 promotes the development of hepatic lipid accumulation

The hepatitis B Virus X (HBx) protein plays a crucial role in the HBV-induced hepatic steatosis. Fatty acid transport protein 2 (FATP2) is a key protein that is involved in hepatic lipogenesis, and it was found to be highly expressed in various metabolic diseases. However, Whether FATP2 is a key factor in the pathogenesis of HBx-induced hepatic steatosis remains unclear. In this study, we found that FATP2 was up-regulated by HBx in vitro and in vivo and participated in HBx-induced hepatic lipid accumulation. Treatment of HBx-expressing cell lines and mice with FATP2 inhibitor (FATP2i) lipofermata ameliorated HBx-induced lipid accumulation and reduced oxidative stress and inflammation caused by lipid accumulation. Moreover, the liver injury of mouse was restored after FATP2i treatment. In summary, our results reveal that FATP2 is a key driver factor for HBx-induced hepatic lipid accumulation, and inhibition of FATP2 can ameliorates lipid accumulation caused by HBx. This study provides new insights into the mechanism of HBV-induced hepatic steatosis.

Insights into the impact of hepatitis B virus on hepatic stellate cell activation

During chronic hepatitis B virus (HBV) infection, hepatic fibrosis is a serious pathological condition caused by virus-induced liver damage. The activation of hepatic stellate cells (HSCs) is a central event in the occurrence and progression of liver fibrosis. Although accumulating evidence has shown that HBV directly stimulates HSC activation, whether the virus infects and replicates in HSCs remains controversial. Inflammation is one of the obvious characteristics of chronic HBV infection, and it has been demonstrated that persistent inflammation has a predominant role in triggering and maintaining liver fibrosis. In particular, the regulation of HSC activation by HBV-related hepatocytes via various inflammatory modulators, including TGF-β and CTGF, in a paracrine manner has been reported. In addition to these inflammation-related molecules, several inflammatory cells are essential for the progression of HBV-associated liver fibrosis. Monocytes, macrophages, Th17 cells, NK cells, as well as NKT cells, participate in the modulation of HBV-related liver fibrosis by interacting with HSCs. This review summarizes current findings on the effects of HBV and the relevant molecular mechanisms involved in HSC activation. Because HSC activation is essential for liver fibrosis, targeting HSCs is an attractive therapeutic strategy to prevent and reverse hepatic fibrosis induced by HBV infection. Video abstract.

Nonsynonymous C1653T Mutation of Hepatitis B Virus X Gene Enhances Malignancy of Hepatocellular Carcinoma Cells

Purpose

Methods

Results

Conclusion

DHA attenuated Japanese Encephalitis virus infection-induced neuroinflammation and neuronal cell death in cultured rat Neuron/glia

Japanese Encephalitis Virus (JEV) is a neurotropic virus and its Central Nervous System (CNS) infection causes fatal encephalitis with high mortality and morbidity. Microglial activation and consequences of bystander damage appear to be the dominant mechanisms for Japanese Encephalitis and complications. Docosahexaenoic acid (DHA), an essential fatty acid and a major component of brain cell membranes, possesses additional biological activities, including anti-apoptosis, anti-inflammation, and neuroprotection. Through this study, we have provided experimental evidence showing the anti-inflammatory, neuroprotective, and anti-viral effects of DHA against JEV infection in rat Neuron/glia cultures. By Neuron/glia and Neuron cultures, DHA protected against neuronal cell death upon JEV infection and reduced JEV amplification. In Neuron/glia and Microglia cultures, the effects of DHA were accompanied by the downregulation of pro-inflammatory M1 microglia, upregulation of anti-inflammatory M2 microglia, and reduction of neurotoxic cytokine expression, which could be attributed to its interference in the Toll-Like Receptor (TLR), Mitogen-Activated Protein Kinase (MAPK), and Interferon/Janus Kinase/Signal Transducers and Activators of Transcription (Stat), along with the NF-κB, AP-1, and c-AMP Response Element Binding Protein (CREB) controlled transcriptional programs. Parallel anti-inflammatory effects against JEV infection were duplicated by G Protein-Coupled Receptor (GPR120) and GPR40 agonists and a reversal of DHA-mediated anti-inflammation was seen in the presence of GPR120 antagonist, while the GPR40 was less effectiveness. Since increasing evidence indicates its neuroprotection against neurodegenerative diseases, DHA is a proposed anti-inflammatory and neuroprotective candidate for the treatment of neuroinflammation-accompanied viral pathogenesis such as Japanese Encephalitis.

KIAA1522 Promotes the Progression of Hepatocellular Carcinoma via the Activation of the Wnt/β-Catenin Signaling Pathway

Purpose

KIAA1522 was previously identified to play a crucial role in cancer development and progression. However, its functions and underlying mechanisms in hepatocellular carcinoma (HCC) remain elusive.

Materials and Methods

To elucidate the role of KIAA1522 in HCC, its expression was assessed using The Cancer Genome Atlas and GEPIA databases. Next, these results were validated by quantitative reverse transcription-polymerase chain reaction, Western blotting, and immunohistochemistry of HCC tissues and cell lines. Flow cytometry, CCK-8, EDU, colony formation, Transwell invasion, and wound healing assays were performed to explore the function of KIAA1522 in HCC in vivo and in vitro. Finally, gene set enrichment analysis was used to identify the pathways involved.

Results

Our results demonstrated that KIAA1522 was highly expressed in HCC tissues and cell lines. Furthermore, KIAA1522 overexpression was associated with unfavorable clinicopathological characteristics. Survival analyses revealed that KIAA1522 overexpression predicted lower recurrence-free and overall survival rates in patients with HCC. Functional studies suggested that KIAA1522 facilitated HCC proliferation, migration, and invasion both in vitro and in vivo. Moreover, KIAA1522 up-regulated the Wnt/β-catenin signaling pathway, as confirmed by TOP-flash/FOP-flash luciferase reporter assays and Western blotting.

Conclusion

In conclusion, we highlighted the oncogenic role of KIAA1522 in HCC and determined its potential as a therapeutic target for HCC.

Activation of GPR43 suppresses TNF-α-induced inflammatory response in human fibroblast-like synoviocytes

Although rheumatoid arthritis (RA) has long posed a major threat to global health, the mechanisms driving the development and progression of RA remain incompletely understood. In the present study, we investigated the effects of G protein-coupled receptor 43 (GPR43/FFAR2) in various aspects of the pathogenesis of RA. To our knowledge, this is the first study to demonstrate that GPR43 is expressed on human fibroblast-like synoviocytes (FLS). Furthermore, we show that GPR43 is upregulated in FLS exposed to tumor necrosis factor-α (TNF-α). Importantly, our findings demonstrate that activation of GPR43 using its specific agonist significantly suppressed expression of the following key factors of RA: cytokines, such as interleukin-6 (IL-6), IL-8, high mobility group protein 1 (HMG-1); chemokines, such as monocyte chemoattractant protein 1 (MCP-1), intercellular adhesion molecule 1 (ICAM-1), and vascular cellular adhesion molecule 1 (VCAM-1); markers of oxidative stress, such as production of reactive oxygen species (ROS) and 4-hydroxynoneal (4-HNE); degradative enzymes, such as matrix metalloproteinase-3 (MMP-3) and MMP-13; and activation of the nuclear factor-κB (NF-κB) inflammatory signaling pathway. These results suggest a promising potential role for GPR43 as a specific target in the treatment and prevention of RA.