Isolation, Transfection, and Culture of Primary Human Monocytes

Formyl peptide receptor 1 and its antagonist T0080 in atherosclerosis

Focal inflammation and arterial damage driven by macrophages are key pathogenic processes in atherosclerosis. However, the mechanisms that regulate these processes remain poorly understood. In this study, we demonstrate that formyl peptide receptor 1 (FPR1) agonist, a mitochondrial N-formyl peptide, is elevated in the blood of patients with atherosclerosis and correlates with carotid stenosis. Macrophages expressing FPR1 were found in atherosclerotic lesions. Conditional deletion of Fpr1 in macrophages reduced plaque formation, local inflammation, and aortic atherosclerosis in apolipoprotein E (ApoE)-/- mice. FPR1 activates protein kinase C (PKC) in macrophages, promoting the production of reactive oxygen species (ROS), tumor necrosis factor alpha (TNF-α) and interleukin-1beta (IL-1β), which accelerates the apoptosis of endothelial cells and smooth muscle cells. To inhibit FPR1 bioactivity, we developed an antagonist, T0080. Therapeutic administration of T0080 attenuates atherosclerotic progression in ApoE-/- mice. Our findings highlight the pivotal role of FPR1 in macrophage-mediated atherosclerotic plaque formation and support further investigation of T0080-mediated FPR1 inhibition as a potential treatment for atherosclerosis.

Survey of In Vitro Model Systems for Investigation of Key Cellular Processes Associated with Atherosclerosis

Atherosclerosis progression is associated with a complex array of cellular processes in the arterial wall, including endothelial cell activation/dysfunction, chemokine-driven recruitment of immune cells, differentiation of monocytes to macrophages and their subsequent transformation into lipid laden foam cells, activation of inflammasome and pro-inflammatory signaling, and migration of smooth muscle cells from the media to the intima. The use of in vitro model systems has considerably advanced our understanding of these atherosclerosis-associated processes and they are also often used in drug discovery and other screening platforms. This chapter will describe key in vitro model systems employed frequently in atherosclerosis research.

Attenuated Negative Feedback in Monocyte-Derived Macrophages From Persons Living With HIV: A Role for IKAROS

Persons living with HIV (PLWH) are at higher risk of developing secondary illnesses than their uninfected counterparts, suggestive of a dysfunctional immune system in these individuals. Upon exposure to pathogens, monocytes undergo epigenetic remodeling that results in either a trained or a tolerant phenotype, characterized by hyper-responsiveness or hypo-responsiveness to secondary stimuli, respectively. We utilized CD14⁺ monocytes from virally suppressed PLWH and healthy controls for in vitro analysis following polarization of these cells toward a pro-inflammatory monocyte-derived macrophage (MDM) phenotype. We found that in PLWH-derived MDMs, pro-inflammatory signals (TNFA, IL6, IL1B, miR-155-5p, and IDO1) dominate over negative feedback signals (NCOR2, GSN, MSC, BIN1, and miR-146a-5p), favoring an abnormally trained phenotype. The mechanism of this reduction in negative feedback involves the attenuated expression of IKZF1, a transcription factor required for de novo synthesis of RELA during LPS-induced inflammatory responses. Furthermore, restoring IKZF1 expression in PLWH-MDMs partially reinstated expression of negative regulators of inflammation and lowered the expression of pro-inflammatory cytokines. Overall, this mechanism may provide a link between dysfunctional immune responses and susceptibility to co-morbidities in PLWH with low or undetectable viral load.

Silencing of SPP1 Suppresses Progression of Tongue Cancer by Mediating the PI3K/Akt Signaling Pathway

Background:

In the present study, we aimed to find an effective target for the treatment of tongue cancer using gene chip screening and signal pathway research.

Methods:

We used microarray screening and gene expression profile analyses to find important differentially expressed genes in tongue cancer. We constructed a protein-protein interaction network, and used enrichment analysis of the Kyoto Encyclopedia of Genes and Genomes to screen for important genes. We then silenced the genes of interest in SCC154 cells to study the relationship with the Phosphatidylinositol 3-kinase/Akt signal pathway. Western blot analyses, the 3-(4,5Dimethylthiazol-yl)-2,5Dimethylthiazol-2-yl)-2,5diphenyltetrazolium bromide (MTT) test, and immunofluorescence assays were used to compare the expression levels of Phosphatidylinositol 3-kinase/Akt signal pathway-related proteins, cell viability, and cell proliferation ability in normal SCC154 cells, Si-RNA SCC154 cells, and gene-silenced SCC154 cells. The scratch test, Transwell test, and western blotting were used to determine migration, invasion, and carcinogenesis.

Results:

Using GSE9844, GSE13601, and GSE31056 gene chips, we identified 93 upregulated genes and 76 downregulated genes in tongue cancer. Using the protein-protein interaction network and Kyoto Encyclopedia of Genes and Genomes enrichment analyses, we further identified 47 differentially expressed genes. Using Kaplan-Meier plotter online tools, we also identified 3 genes (SPP1, Recombinant Human Secreted Phosphoprotein 1; PLAU, plasminogen activator urinary; and APP, amyloid precursor protein). Compared with normal SCC154 cells and Si-RNA control SCC154 cells, the expressions of Phosphatidylinositol 3-kinase/Akt pathway proteins in si-SPP1 SCC154 cells were significantly decreased (*P < 0.05), and the protein activities and proliferation abilities were also significantly decreased (*P < 0.05), while the migration ability, invasion ability, and cancer forming ability were significantly increased (*P < 0.05).

Conclusion:

Inhibition of the SPP1 gene may have a therapeutic effect on tongue cancer, and could be an effective target for the treatment of this disorder.