Nanoparticles (NPs)-mediated Siglec15 silencing and macrophage repolarization for enhanced cancer immunotherapy

T cell infiltration and proliferation in tumor tissues are the main factors that significantly affect the therapeutic outcomes of cancer immunotherapy. Emerging evidence has shown that interferon-gamma (IFNγ) could enhance CXCL9 secretion from macrophages to recruit T cells, but Siglec15 expressed on TAMs can attenuate T cell proliferation. Therefore, targeted regulation of macrophage function could be a promising strategy to enhance cancer immunotherapy via concurrently promoting the infiltration and proliferation of T cells in tumor tissues. We herein developed reduction-responsive nanoparticles (NPs) made with poly (disulfide amide) (PDSA) and lipid-poly (ethylene glycol) (lipid-PEG) for systemic delivery of Siglec15 siRNA (siSiglec15) and IFNγ for enhanced cancer immunotherapy. After intravenous administration, these cargo-loaded could highly accumulate in the tumor tissues and be efficiently internalized by tumor-associated macrophages (TAMs). With the highly concentrated glutathione (GSH) in the cytoplasm to destroy the nanostructure, the loaded IFNγ and siSiglec15 could be rapidly released, which could respectively repolarize macrophage phenotype to enhance CXCL9 secretion for T cell infiltration and silence Siglec15 expression to promote T cell proliferation, leading to significant inhibition of hepatocellular carcinoma (HCC) growth when combining with the immune checkpoint inhibitor. The strategy developed herein could be used as an effective tool to enhance cancer immunotherapy.

Interferon-α modulates HBV specific T-cell response to inhibit viral gene expression in chronic HBV infection mouse model / 中国感染与化疗杂志

Objective To explore the antiviral effect and mechanism of interferon-α (IFN-α) in chronic HBV infection mouse model by hydrodynamic tail vein injection. Methods Chronic HBV infection mouse model was constructed with C57BL/6j mice by hydrodynamic tail vein injection of pAAV-HBV1.2 plasmid. Serum IFN-α was determined by ELISA after injection of IFNα- expressing plasmid (i.e., plasmid pKCMvint.IFN-α-2a) or control plasmid pKCMvint. HBsAg and HBeAg levels were assayed on Abbot ARCHITECT i2000SR. Total lymphocytes in liver or spleen were counted and the frequency and function of CD8+T cells and HBV-specific CD8+T cells were analyzed by flow cytometry. Results Serum IFN-α expression level was significantly higher in the animals injected with pKCMvint.IFN-α-2a plasmid than in control group (P＜0.01). Serum HBsAg decreased quickly 12 days after injection and significantly lower than control group. Serum HBeAg was undetectable after IFN-α expression. Interestingly, the frequency of CD8+T cells in the liver of animals injected with pKCMvint.IFN-α-2a plasmid was significant higher than control group (P＜0.05), while total liver lymphocytes and HBV-specific CD8+T cells had a similar trend. Consistently, the HBV-specific CD8+T cells in IFN-α-expressing animals showed higher level of producing IFN-γ, TNF-α and IL-2 than control group. IFN-γ production was significantly different between IFN-α- expressing group and control group (P＜0.05). Conclusions IFN-α can increase the frequency and function of liver CD8+T cells to inhibit HBV gene expression in chronic HBV infection mouse model.

E17110 promotes reverse cholesterol transport with liver X receptor β agonist activity in vitro

Liver X receptor (LXR) plays an important role in reverse cholesterol transport (RCT), and activation of LXR could reduce atherosclerosis. In the present study we used a cell-based screening method to identify new potential LXRβ agonists. A novel benzofuran-2-carboxylate derivative was identified with LXRβ agonist activity: E17110 showed a significant activation effect on LXRβ with an EC50 value of 0.72 μmol/L. E17110 also increased the expression of ATP-binding cassette transporter A1 (ABCA1) and G1 (ABCG1) in RAW264.7 macrophages. Moreover, E17110 significantly reduced cellular lipid accumulation and promoted cholesterol efflux in RAW264.7 macrophages. Interestingly, we found that the key amino acids in the LXRβ ligand-binding domain had distinct interactions with E17110 as compared to TO901317. These results suggest that E17110 was identified as a novel compound with LXRβ agonist activity in vitro via screening, and could be developed as a potential anti-atherosclerotic lead compound.

The in vitro anti-atherosclerotic activity of compound E0869 / 药学学报

ATP-binding cassette transporter A1 (ABCA1) and scavenger receptor class B type I (SR-BI/CLA-1) are the key proteins in reverse cholesterol transport (RCT). The high expression of ABCA1 and SR-BI/CLA-1 can decrease the danger of atherosclerosis. The purpose of the study is to find ABCA1 and CLA-1up-regulators for treating atherosclerosis by using cell-based high throughput screening models. Among 20 000 compounds screened, E0869 [1-(3, 4-dimethylphenyl)-1-oxopropan-2-yll4-((methylsulfonyl)methyl)benzoate] was found as the positive hit. The up-regulated activities of E0869 in ABCAl1-LUC and bCA-l1-LUC HepG2 cell were 160% and 175%, respectively. The EC50 values of E0869 in ABCAl1-LUC and CLA-l1-LUC HepG2 cell were 3.79 and 1.42 pμol- x ,(-1) respectively. E0869 could upregulate the mRNA and protein levels of ABCA1, SR-BI/CLA-1 and ABCGJ1genes in HepG2 and RAW264.7 cells by Real-Time Quantitative PCR and Western blotting analysis, but could not influence the expression of FAS, SREBP-l1 and CD36. Foam cell assay showed that E0869 could inhibit lipids accumulation in mouse peritoneal macrophages RAW264.7. Cholesterol efflux assay showed that E0869 could induce HDL-mediated cholesterol efflux in mouse peritoneal macrophages RAW264.7. In conclusion, E0869 could up-regulate ABCA1 and CLA-1 activity, and had good anti-atherosclerotic activity in vitro.

The in vitro anti-atherosclerotic activity of compound IMB-1680 / 药学学报

In the previous study, a high-throughput screening method was established to find the antagonists of CD36. In the present study, a new compound named IMB-1680 was found using this method. The anti-atherosclerotic activities of IMB-1680 were then evaluated. Dose-dependent activities of IMB-1680 were detected by using Sf9 [hCD36] and CHO [hCD36] models. Fluorescence microscopic photography and flow cytometry were used to analyze uptake of mLDL. Foam cell test with RAW264.7 macrophages was used to examine lipid accumulation. The results showed that IMB-1680 inhibited CD36 activity with IC50 of 2.80 and 8.79 micromol x L(-1) in Sf9[hCD36] and CHO [hCD36] cells, respectively. Fluorescence microscopic photography and flow cytometry revealed that IMB-1680 could significantly reduce DiI-AcLDL uptake. Meanwhile, IMB-1680 also could reduce lipids accumulation in RAW264.7 macrophages. In all, the data indicated that IMB-1680 might be a potent effective anti-atherosclerotic leading compound.

Synthesis and structure-activity relationship of 13-hexylberberine analogues as CD36 antagonists / 药学学报

Scavenger receptor CD36 could bind and endocytose oxLDL into macrophages which were then differentiated into foam cells that constitute the atherosclerotic lesion core, and was considered to be a potential target to treat atherosclerosis. In the establishment of the compound library of berberine (BBR, 1) analogues, we discovered that 13-hexylberberine (2) showed an antagonistic activity against CD36. Taking 2 as the lead compound, 21 derivatives were synthesized and their antagonistic activities were evaluated via an ELISA-like high-throughput screening (HTS) model. The primary structure-activity relationships were studied. It was indicated that the introduction of suitable groups at the 2- and 3-position of the aromatic ring A or at the 9-position of the aromatic ring D could enhance the activity. Among the 21 studied compounds, 7g bearing a benzyloxyl group at the 9-position provided a highest CD36 antagonistic activity with the IC50 value of 7.7 micromol L(-1). Besides, its antagonistic activity was further verified with Sf9 insect cell HTS model. So berberine analogues are a new family of CD36 receptor antagonists and worthy to be studied further.