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RNA expression profile of liver-specific IGF2BP2/IMP2/p62 transgenic mice compared to wild-type mice

ABSTRACT: Livers of p62/IMP2-2 transgenic mice with C57Bl6J/DBA2 background as described in Tybl et al., J Hepatol, 2011

ORGANISM(S): Mus musculus

PROVIDER: GSE130999 | GEO | 2019/05/31

REPOSITORIES: GEO

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Project description:High expression levels of the RNA binding protein IGF2BP2/IMP2 are correlated with increased tumor cell proliferation, invasion, and poor prognosis in the clinic. Tumor cells release extracellular vesicles (EVs) that can polarize macrophages towards tumor-associated macrophages (TAMs), which play a role in tumor progression. However, there is a lack of understanding of IMP2’s effect on TAMs. EVs were isolated from colorectal cancer HCT116 parental (WT) and CRISPR/Cas9 IMP2 knockout (KO) cells via ultracentrifugation and tangential flow filtration. EVs were characterized according to MISEV guidelines and microRNA cargo was assessed by microRNA-Seq. Primary human monocyte-derived macrophages were polarized towards a TAM-like phenotype by EVs and the expression of genes and surface markers was assessed by qPCR and flow cytometry, respectively. Morphological changes of macrophages as well as the migratory potential of cancer cells were assessed by the IncuCyte® system and macrophage matrix degradation potential by zymography. Changes in the metabolic activity of macrophages were quantified in live cells in a Seahorse® analyzer. For in vivo studies, EVs were injected into the yolk sac of zebrafish embryos, and macrophages were isolated by fluorescence-activated cell sorting. EV samples from both WT and KO EVs had a similar size and concentration and were positive or CD9, CD81, CD63, and ALIX. The expression of tumor-promoting genes was higher in macrophages polarized with WT EVs, while the expression of tumor-suppressing TNF and IL6 was reduced. WT EV-polarized macrophages showed a higher abundance of TAM-like surface markers, higher matrix degrading activity, as well as a higher promotion of cancer cell migration. They exhibited a higher basal oxygen consumption rate and a lower extracellular acidification rate. microRNA-seq revealed a significant difference in the microRNA composition of WT and KO EVs. Macrophages transfected with miR-181a-5p mimic showed a lower level of the phosphatase DUSP6. Zebrafish macrophages upon polarization with WT EVs showed lower expression of IL6 and TNF. Our results show that IMP2 can determine the cargo of EVs released by cancer cells, thereby modulating the EVs’ actions on macrophages. Expression of IMP2 is responsible for the secretion of EVs that polarize macrophages toward a tumor-promoting phenotype.

Project description:Huntington's disease (HD) is a dominantly inherited genetic disease caused by mutant huntingtin (htt) protein with expanded polyglutamine tracts. A neuropathological hallmark of HD is the presence of neuronal inclusions of mutant htt. p62 is an important regulatory protein in selective autophagy, a process by which aggregated proteins are degraded, and it is associated with several neurodegenerative disorders including HD. Here we investigated the effect of p62 depletion in three HD model mice: R6/2, HD190QG and HD120QG mice. We found that loss of p62 in these models led to longer lifespans and reduced nuclear inclusions, although cytoplasmic inclusions increased with polyglutamine length. In mouse embryonic fibroblasts (MEFs) with or without p62, mutant htt with a nuclear localization signal (NLS) showed no difference in nuclear inclusion between the two MEF types. In the case of mutant htt without NLS, however, p62 depletion increased cytoplasmic inclusions. Furthermore, to examine the effect of impaired autophagy in HD model mice, we crossed R6/2 mice with Atg5 conditional knockout mice. These mice also showed decreased nuclear inclusions and increased cytoplasmic inclusions, similar to HD mice lacking p62. These data suggest that the genetic ablation of p62 in HD model mice enhances cytoplasmic inclusion formation by interrupting autophagic clearance of polyQ inclusions. This reduces polyQ nuclear influx and paradoxically ameliorates disease phenotypes by decreasing toxic nuclear inclusions. Gene expression profiles were analyzed to examine the effects of p62 depletion in mouse with or without mutant huntingtin exon 1 To examine the effect of p62 depletion on the transcriptome of Huntington's disease model mice, we crossed p62 knockout mice with HD model mice. We extracted total RNA from the striatum of these mice at 8 weeks and used for a microaaray analysis. The samples are HD transgenic mice with p62 knockout (HD_p62KO), HD mice with normal p62 (HD_p62WT), non-HD-transgenic mice with p62 knockout (NT_p62KO), and non-HD-transgenic mice with normal p62 (NT_p62WT).

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RNA expression profile of liver-specific IGF2BP2/IMP2/p62 transgenic mice compared to wild-type mice

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