Project description:Gene expression was analyzed in TAM from mice injected with ID8 ovarian cancer cells intraperitoneally in ABC a1/g1 fl/fl-LysM-Cre mice. Tumor-associated macrophages (TAM) have been shown to have important roles in the malignant progression of various cancers. However, macrophages also posses intrinsic tumoricidal activity and can promote the activity of cytotoxic lymphocytes, but they rapidly adopt an alternative phenotype within tumors, associated with immune-suppression and trophic functions that support tumor growth. The mechanisms that promote TAM polarization in the tumor-microenvironment remain poorly understood, these mechanisms may represent important therapeutic targets to block the tumor-promoting functions of TAM and restore their anti-tumor potential. Here we have characterized TAM in a mouse model of metastatic ovarian cancer. We show that ovarian cancer cells promote membrane-cholesterol efflux and the depletion of lipid rafts from macrophages. Increased cholesterol efflux promoted IL-4 mediated reprogramming while inhibiting IFNg-induced gene expression. These studies reveal an unexpected role for tumor-induced membrane-cholesterol efflux in driving the IL-4 signaling and the tumor-promoting functions of TAM, while rendering them refractory to pro-inflammatory stimuli. Thus, preventing cholesterol efflux in TAM could represent a novel therapeutic strategy to block pro-tumor functions and restore anti-tumor immunity.
Project description:Gene expression was analyzed in peritoneal macrophages and TAM from mice injected with ID8 ovarian cancer cells intraperitoneally 28 days after tumor implantation. Tumor-associated macrophages (TAM) have been shown to have important roles in the malignant progression of various cancers. However, macrophages also posses intrinsic tumoricidal activity and can promote the activity of cytotoxic lymphocytes, but they rapidly adopt an alternative phenotype within tumors, associated with immune-suppression and trophic functions that support tumor growth. The mechanisms that promote TAM polarization in the tumor-microenvironment remain poorly understood, these mechanisms may represent important therapeutic targets to block the tumor-promoting functions of TAM and restore their anti-tumor potential. Here we have characterized TAM in a mouse model of metastatic ovarian cancer. We show that ovarian cancer cells promote membrane-cholesterol efflux and the depletion of lipid rafts from macrophages. Increased cholesterol efflux promoted IL-4 mediated reprogramming while inhibiting IFNg-induced gene expression. These studies reveal an unexpected role for tumor-induced membrane-cholesterol efflux in driving the IL-4 signaling and the tumor-promoting functions of TAM, while rendering them refractory to pro-inflammatory stimuli. Thus, preventing cholesterol efflux in TAM could represent a novel therapeutic strategy to block pro-tumor functions and restore anti-tumor immunity.
Project description:Splenocytes were separated from Lrrc8af/f and Lrrc8af/f Cd4-Cre;OT-I mice. The splenocytes were stimulated with indicated peptides (unstime/ SIINFEKL-10pM(NL)/ SIINFEKL-1000pM(NH)/ SIIGFEKL-1000nM(G4)) for 6 hours. The OT-I CD8+ T cells were labeled with Va2-PE/CD8-A700 and sorted for the sequencing.
Project description:Changes in the transcript profile due to ABCA1 expression in murine liver samples was evaluated in LDL receptor -/- genetic backgrounds. Experiment Overall Design: Case (ABCA1-transgenic) versus control (wild-type) design with 4 biological replicates per condition
Project description:Temporally controlling cre recombinase through tamoxifen (TAM) induction has many advantages for biomedical research studies. While most projects use TAM induction of mice at early post-natal or adolescence (<2m.o.) ages, age-related neurodegeneration and aging studies can require experimental designs with cre induction in older mice (>12m.o.). While anecdotally reported to be problematic, there are no published comparisons of TAM mediated cre induction at young and older ages. Cx3cr1creERT2 mice for studying microglial were crossed to a floxed NuTRAP reporter to compare cre induction at young (3m.o.) and old (18m.o) ages. Specificity and efficiency microglial labeling was identical at 24m.o. in mice induced with TAM at 3m.o. or 18m.o. of age. Age-related microglial translatomic changes were nearly identical regardless of TAM induction age. While each cre and flox mouse line should be validated before use, these findings demonstrate that TAM induction of cres can be performed even into older mouse ages.
Project description:ATP binding cassette transporter A1 (ABCA1) regulates cellular cholesterol efflux. We characterized the gene expression changes following hepatocyte specific ABCA1 deletion in mice. We report that genes and pathways related to lipogenesis were downregulated in mice with hepatocyte specific ABCA1 deletion compared to floxed controls.
Project description:We analyzed transcriptome differences of antigen-specific pre-GC B cells. We transferred wildtype (CD4-Cre) or BCL6-insufficient (CD4-CrexBcl6fl/+) OT-II T cells into SAP-deficient mice and immunized these mice with NP-OVA. By day 3 post immunization, we sort-purified NP-binding B cells that were developing into GCs and conducted RNA-seq analyses of their transcriptome. NP+IgDlowB220+ pre-GC B cells from recipients of the same group were pooled to sort-purify 4 200-cell repeats. Using a gene expression signature induced by CD40 signaling in B cells for enrichment analysis, we found such CD40-induced gene set expression was significantly deprived in those NP-binding B cells helped by CD4-Cre´Bcl6fl/+ T cells. These data suggest BCL6 insufficiency in T cells leads to impaired CD40L signaling to B cells.
Project description:Wheat cultivars ‘TAM 111’ and ‘TAM 112’ have been dominantly grown in the Southern U.S. Great Plains for many years due to their excellent, yet variable, drought tolerance. To identify the molecular basis and genetic control of drought tolerance in these two landmark cultivars, RNA-seq analysis was conducted to compare gene expression difference in flag leaves under fully irrigated (wet) and water deficient (dry) conditions. Of the 122,017 gene sequences assembled, 2,254 genes showed significantly altered expression patterns under dry and wet conditions in the two cultivars. TAM 111 had 593 and 1,532 dry-wet differentially expressed genes (DEGs), and TAM 112 had 777 and 1,670 at heading and grain-filling stages, respectively. The two cultivars have 1,214 (53.9%) dry-wet DEGs in common, which agreed with their excellent adaption to drought, but 438 and 602 dry-wet DEGs were respectively shown only in TAM 111 and TAM 112 suggested that each may have a specific mechanism to cope with drought. Annotation of all 2,254 genes with dry-wet expression difference found 1,855 have functions related to biosynthesis, stress responses, defense responses, transcription factors and cellular components related to ion or protein transportation and signal transduction. Comparing hierarchical structure of biological processes, molecule functions and cellular components revealed the significant regulation differences between TAM 111 and TAM 112, particularly for genes of phosphorylation and adenyl ribonucleotide binding, and proteins located in nucleus and plasma membrane. Comparing gene expressions involved in responses to stresses of water deprivation, heat and oxidative, ABA-induced signal pathway and transcription regulation found TAM 112 have more specific dry-wet DEGs than TAM 111 with most of them up-regulated, indicating that TAM 112 is more active than TAM 111 in response to drought. In addition, 399 dry-wet DEGs with unknown functions included 258 genes encoding predicted uncharacterized proteins and 141 unannotated genes with no similar sequences identified in the databases. These may represent novel genes related to drought response in TAM 111 or TAM 112. This research thus revealed different drought-tolerance mechanisms in TAM 111 and TAM 112 and identified useful drought tolerance genes for wheat adaption.
Project description:Glaucoma is an optic neuropathy characterized by progressive degeneration of retinal ganglion cells (RGCs) and visual loss. Previous studies have reported that the variation of the ATP-binding cassette transporter 1 (ABCA1) gene is linked to a higher risk of glaucoma in humans, but the pathological mechanisms remain unknown. Here we report that ABCA1 loss, especially in astrocytes, causes optic neuropathy. ABCA1 was mainly expressed in astrocytes rather than neurons, and that knockout of Abca1 gene under GFAP promoter (Glia-KO) caused age-associated RGC degeneration and ocular dysfunction without affecting intraocular pressure, a major risk factor for glaucoma. Glia-KO mice showed age-associated changes in astrocyte reactivity accompanied by the accumulation of cholesterol, a major substrate of ABCA1. Single-cell RNA sequencing revealed that Abca1 deficiency causes astrocyte-triggered inflammation and increased sensitivity of RGCs against excitotoxicity. Altogether, these findings suggest that astrocytic dysfunction caused by ABCA1 loss triggers age-associated optic neuropathy-like pathology.