Transcription profiling of mouse embryonic fibroblasys from Wip1+/+ or -/- animals after gamma radiation
Ontology highlight
ABSTRACT: Assessment of p53 targets by gene expression array analysis in irradiated and nonirradiated Wip1+/+ and Wip1-/- MEFs. Experiment Overall Design: mRNA from each set of cells harvested four hours after IR (5 Gy) was Experiment Overall Design: used for gene expression microarray analysis of p53 target genes using the Affymetrix Mouse Genome 430 2.0 Chips.
Project description:Assessment of p53 targets by gene expression array analysis in irradiated and nonirradiated Wip1+/+ and Wip1-/- MEFs. Keywords: response to gamma radiation
Project description:Targeting the Mdm2 oncoprotein by drugs has the potential of re-establishing p53 function and tumor suppression. However, Mdm2-antagonizing drug candidates, e. g. Nutlin-3a, often fail to abolish cancer cell growth sustainably. To overcome these limitations, we inhibited Mdm2 and simultaneously a second negative regulator of p53, the phosphatase Wip1/PPM1D. When combining Nutlin-3a with the Wip1 inhibitor GSK2830371 in the treatment of p53-proficient but not p53-deficient cells, we observed enhanced phosphorylation (Ser 15) and acetylation (Lys 382) of p53, increased expression of p53 target gene products, and synergistic inhibition of cell proliferation. Surprisingly, when testing the two compounds individually, largely distinct sets of genes were induced, as revealed by deep sequencing analysis of RNA. In contrast, the combination of both drugs led to an expression signature that largely comprised that of Nutlin-3a alone. Moreover, the combination of drugs, or the combination of Nutlin-3a with Wip1-depletion by siRNA, activated p53-responsive genes to a greater extent than either of the compounds alone. Simultaneous inhibition of Mdm2 and Wip1 enhanced cell senescence and G2/M accumulation. Taken together, the inhibition of Wip1 might fortify p53-mediated tumor suppression by Mdm2 antagonists.
Project description:Hematopoietic stem cell (HSC) aging underlies many age-related hematopoietic disorders. Accumulation of DNA damage is a hallmark of HSC aging. Wild-type p53-induced phosphatase 1 (Wip1) is a homeostatic regulator of DNA damage response. We used microarrays to detail the global programme of gene expression in Wip1 KO HSC Wild-type p53-induced phosphatase 1 (Wip1) knockout HSC and Wild type HSC were selected for RNA extraction and hybridization on Affymetrix microarrays.
Project description:Hematopoietic stem cell (HSC) aging underlies many age-related hematopoietic disorders. Accumulation of DNA damage is a hallmark of HSC aging. Wild-type p53-induced phosphatase 1 (Wip1) is a homeostatic regulator of DNA damage response. We used microarrays to detail the global programme of gene expression in Wip1 KO HSC
Project description:Spermatogenesis plays an important role in the mammalian testis, involving in the complex processes of mitosis, meiosis, and spermiogenesis. Spermatogenesis may also be disrupted in the absence of the immunological and ‘fence’ functions of the BTB, resulting in male subfertility or infertility. Mice lacking wild-type p53-induced phosphatase 1 (Wip1) display male reproductive organ defects, but the molecular mechanisms underlying these abnormalities remain unclear. We explored the function of Wip1 in spermatogenesis and fertility by examining differences in the expressed testis proteome and phosphoproteome between Wip1-deficient and wild-type mice using a proteomics approach. 90 proteins and 178 phosphoproteins were differentially regulated between these two groups of mice. These results suggested that proinflammatory cytokines may impair the blood–testis barrier dynamics by decreasing the expression of junction-associated proteins, which effect could be partially responsible for the subfertility and spermatogenesis defects in Wip1-knockout mice.
Project description:The wild-type p53-inducible protein phosphatase WIP1, encoded by the PPM1D gene, is a negative regulator of p53 and is involved in cell cycle control and DNA damage stress-response. In acute myeloid leukemia (AML), the restoration of p53 activity through MDM2 inhibition proved efficacy in a number of combination strategies. We investigated the therapeutic potential of its inhibition through the selective WIP1 inhibitor (WIP1i) GSK2830371, in association with the MDM2 inhibitor Nutlin-3a (Nut-3a) in a panel of AML cell lines and performed gene expression analysis of single agent and combined treatments. A p53-related signature was significantly upregulated in the TP53-wildtype MV-4-11 AML cell line. Moreover, drug-specific transcriptional changes likely contribute to the synergistic combination effect.
Project description:Collapsing focal segmental glomerulosclerosis (FSGS), also known as collapsing glomerulopathy (CG), is the most aggressive variant of FSGS and is characterized by rapid progression to end-stage kidney disease (ESKD). Understanding CG pathogenesis represents a key step for the development of targeted therapies. Previous work implicated the telomerase protein component TERT in CG pathogenesis, as transgenic TERT expression in adult mice resulted in a CG resembling that seen in human primary CG and HIV-associated nephropathy (HIVAN). We used the telomerase-induced mouse model of CG (i-TERTci mice) to identify mechanisms to inhibit CG pathogenesis. We found that inactivation of WIP1 phosphatase, a p53 target acting in a negative feedback loop, blocks disease initiation in i-TERTci mice. Repression of disease initiation upon WIP1 deficiency is associated with senescence enhancement and requires TGF-b functions. We further assessed efficacy of a pharmacologic treatment to reduce disease severity in both i-TERTci mice and in a mouse model of HIVAN (Tg26 mice). We found that pharmacologic inhibition of WIP1 enzymatic activity in either telomerase mice with CG or in Tg26 mice promotes partial remission of proteinuria and ameliorates renal histopathologic features. Histological as well as high throughput sequencing methods further showed that selective inhibition of WIP1 does not promote kidney fibrosis or inflammation. Our findings suggest that targeting WIP1 may be an effective therapeutic strategy for patients with CG.
Project description:RNA expression profiles from 12 (twelve) osteosarcomas arisen from p53+/- mouse were compared with a mc3T3 osteoblast control, and a rhabdomyosarcoma expression profile which was from a mouse with the same genetic background. Experiment Overall Design: Total RNA was extracted from 12 osteosarcomas and 1 rhabdomyosarcoma, both arisen from p53+/- mice. Total RNA was also extracted from a cultured mc3T3 osteoblast cell line as control. RNA microarray was performed on the 14 samples, and expression profiles were compared.
Project description:The wild-type p53-induced phosphatase 1 (WIP1) frustrated mice exhibited defects in reproductive organs. This study aimed to understand how Wip1 deficiency affects the spermatogenesis or maturation. We employed the Wip1-/- mouse model and conducted a gel-free iTRAQ LC-MS/MS based quantitative proteomics analysis of whole epididymis including the sperms and somatic tissue. A total of 8763 proteins were identified, of which 91 were significantly differentially expressed proteins (DEPs) in the Wip1 depleted mice. Four DEPs (PRM2, ODF1, PIWIL1 and KLHL10) were confirmed with western blotting. The DEPs enriched in biological process of reproduction were identified by GO analysis and further confirmed in the mouse phenotype database. Pathway analysis suggested that Smac/Diablo-mediated apoptosis pathway and SERPINA3-mediated inflammatory process might contribute to the atrophy and the marked sperm decrease in epididymis. Network analysis of productivity related DEPs revealed possible interactions that WIP1 might affect the sperm maturation by decreasing the outer dense fiber protein 1 (ODF1) and protamine-2 (PRM2), and increasing the PIWIL1/MIWI through p53. PRM2 was down-regulated and PIWIL1 was up-regulated by immunohistochemistry staining. It was further confirmed that the spermatid deficiency began from the testis observed by HE staining. Therefore, WIP1 disruption caused the deficiency of spermatogenesis potentially through regulating the expression of the above DEPs and pathways.
Project description:The number of newly-formed neurons declines rapidly during aging. Here we describe an important mechanism that contributes to this decline via Wip1-dependent regulation of neuronal differentiation. We found that Wip1 is expressed in neural stem/progenitor cells (NPCs) of the mouse subventricular zone and its upregulation at physiological levels maintained higher NPC numbers and neuronal differentiation in old mice. This resulted in markedly improved neuron formation and rescued a functional defect in fine odor discrimination in old mice. We identified Dkk3 as a key downstream target of Wip1 and found that its expression in SVZ is restricted to NPCs. Functionally, Dkk3 inhibited neuroblast formation by suppressing Wnt signaling, while deletion of Dkk3 or pharmacological reactivation of the Wnt pathway improved neuron formation and olfactory function in aged mice. We propose that Wip1 controls a Dkk3-dependent inhibition of neuronal differentiation during aging and thus regulating Wip1 levels could prevent certain aspects of functional decline of the aging brain. We found if neurospheres were derived from 18 months old mice, Wip1 transgenic neurospheres were more neurogenic than wt ones. This microarray was a pilot experiment to search the mechanism how Wip1 Transgene promoted neurogenesis, and found Dkk3 as a potential mediator.