Huntingtons 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.
Depletion of p62 reduces nuclear inclusions and paradoxically ameliorates disease phenotypes in Huntington's model mice.
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View SamplesBackground: Glioblastoma is the most aggressive form of brain tumors showing resistance to treatment with various chemotherapeutic agents. The most effective way to eradicate glioblastoma requires the concurrent inhibition of multiple signaling pathways and target molecules involved in the progression of glioblastoma. Recently, we obtained a series of 1,2,3,4-tetrahydroisoquinoline alkaloids with potent anti-cancer activities, including ecteinascidin-770 (ET-770; the compound 1a) and renieramycin M (RM; the compound 2a) from Thai marine invertebrates, together with a 2-N-4-pyridinecarbonyl derivative of ET-770 (ET-770-DR; the compound 3). We attempted to characterize the molecular pathways responsible for cytotoxic effects of these compounds on a human glioblastoma cell line U373MG. Methods: We studied the genome-wide gene expression profile on microarrays and molecular networks by using pathway analysis tools of bioinformatics. Results: All of these compounds dissolved in dimethyl sulfoxide (DMSO) as a vehicle induced apoptosis of U373MG cells at nanomolar concentrations. The compound 3 reduced the expression of 417 genes and elevated the levels of 84 genes, while ET-770 downregulated 426 genes and upregulated 45 genes. RM decreased the expression of 274 genes and increased the expression of 9 genes. The set of 196 downregulated genes and 6 upregulated genes showed an overlap among all the compounds, suggesting an existence of the common pathways involved in induction of apoptosis. We identified the ErbB (EGFR) signaling pathway as one of the common pathways enriched in the set of downregulated genes, composed of PTK2, AKT3, and GSK3B serving as key molecules that regulate cell movement and the nervous system development. Furthermore, a GSK3B-specific inhibitor induced apoptosis of U373MG cells, supporting an anti-apoptotic role of GSK3B. Conclusion: Molecular network analysis is a useful approach not only to characterize the glioma-relevant pathways but also to identify the network-based effective drug targets.
Molecular network profiling of U373MG human glioblastoma cells following induction of apoptosis by novel marine-derived anti-cancer 1,2,3,4-tetrahydroisoquinoline alkaloids.
Specimen part, Cell line, Treatment
View SamplesNasu-Hakola disease (NHD), also designated polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy (PLOSL), is a rare autosomal recessive disorder characterized by progressive presenile dementia and formation of multifocal bone cysts, caused by a loss-of-function mutation of DAP12 or TREM2. TREM2 and DAP12 constitute a receptor/adaptor complex expressed on osteoclasts, dendritic cells, macrophages, monocytes, and microglia. At present, the precise molecular mechanisms underlying development of leukoencephalopathy and bone cysts in NHD remain largely unknown. We established THP-1 human monocyte clones that stably express small interfering RNA (siRNA) targeting DAP12 for serving as a cellular model of NHD. Genome-wide transcriptome analysis identified a set of 22 genes consistently downregulated in DAP12 knockdown cells. They constituted the molecular network closely related to the network defined by cell-to-cell signaling and interaction, hematological system development and function, and inflammatory response, where NF-kappaB acts as a central regulator. These results suggest that a molecular defect of DAP12 in human monocytes deregulates the gene network pivotal for maintenance of myeloid cell function in NHD. We found that both DAP12 knockdown and control clones were capable of equally responding to phorbol 12-myristate 13-acetate (PMA), a known inducer of morphological differentiation of THP-1 cells, by exhibiting almost similar gene expression profiles between both, following a 24-hour exposure to 50 nM PMA.
Gene expression profile of THP-1 monocytes following knockdown of DAP12, a causative gene for Nasu-Hakola disease.
Specimen part
View SamplesNeural stem cells (NSC) with self-renewal and multipotent properties serve as an ideal cell source for transplantation to treat spinal cord injury, stroke, and neurodegenerative diseases. To efficiently induce neuronal lineage cells from NSC for neuron replacement therapy, we should clarify the intrinsic genetic programs involved in a time and place-specific regulation of human NSC differentiation. Recently, we established an immortalized human NSC clone HB1.F3 to provide an unlimited NSC source applicable to genetic manipulation for cell-based therapy. To investigate a role of neurogenin 1 (Ngn1), a proneural basic helix-loop-helix (bHLH) transcription factor, in human NSC differentiation, we established a clone derived from F3 stably overexpressing Ngn1. Genome-wide gene expression profiling identified 250 upregulated genes and 338 downregulated genes in Ngn1-overexpressing F3 cells (F3-Ngn1) versus wild-type F3 cells (F3-WT). Notably, leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5), a novel stem cell marker, showed a robust increase in F3-Ngn1.
Stable expression of neurogenin 1 induces LGR5, a novel stem cell marker, in an immortalized human neural stem cell line HB1.F3.
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View SamplesA synthetic analog of sphingosine named FTY720 (Fingolimod), phosphorylated by sphingosine kinase-2, interacts with sphingosine-1-phosphate (S1P) receptors expressed on various cells. FTY720 suppresses the disease activity of multiple sclerosis (MS) chiefly by inhibiting S1P-dependent egress of autoreactive T lymphocytes from secondary lymphoid organs, and possibly by exerting anti-inflammmatory and neuroprotective effects directly on brain cells. However, at present, biological effects of FTY720 on human microglia are largely unknown. We studied FTY720-mediated apoptosis of a human microglia cell line HMO6. The exposure of HMO6 cells to non-phosphorylated FTY720 (FTY720-non-P) induced apoptosis in a dose-dependent manner with IC50 of 10.62.0 microM, accompanied by the cleavage of caspase-7 and caspase-3 but not of caspase-9. The apoptosis was inhibited by Z-DQMD-FMK, a caspase-3 inhibitor, but not by Pertussis toxin, a Gi protein inhibitor, suramin, a S1P3/S1P5 inhibitor, or W123, a S1P1 competitive antagonist, although HMO6 expressed S1P1, S1P2, and S1P3. Furthermore, both phosphorylated FTY720 (FTY720-P) and SEW2871, a S1P1 selective agonist did not induce apoptosis of HMO6. Genome-wide gene expression profiling and molecular network analysis indicated activation of transcriptional regulation by sterol regulatory element-binding protein (SREBP) in FTY720-non-P-treated HMO6 cells. Western blot verified activation of SREBP2 in these cells, and apoptosis was enhanced by pretreatment with simvastatin, an activator of SREBP2, and by overexpression of the N-terminal fragment of SREBP2. These observations suggest that FTY720-non-P-induced apoptosis of HMO6 human microglia is independent of S1P receptor binding, and positively regulated by the SREBP2-dependent proapoptotic signaling pathway.
Non-phosphorylated FTY720 induces apoptosis of human microglia by activating SREBP2.
Specimen part
View SamplesInflammasome, activated by pathogen-derived and host-derived danger signals, constitutes a multimolecular signaling complex that serves as a platform for caspase-1 (CASP1) activation and interleukin-1beta (IL1B) maturation. The activation of NLRP3 inflammasome requires two-step signals. The first priming signal (Signal 1) enhances gene expression of inflammasome components. The second activation signal (Signal 2) promotes the assembly of inflammasome components. Deregulated activation of NLRP3 inflammasome contributes to the pathological processes of Alzheimers disease (AD) and multiple sclerosis (MS). However, at present, the precise mechanism regulating NLRP3 inflammasome activation and deactivation remains largely unknown. By genome-wide gene expression profiling, we studied the molecular network of NLRP3 inflammasome activation-responsive genes in a human monocyte cell line THP-1 sequentially given two-step signals. We identified the set of 83 NLRP3 inflammasome activation-responsive genes. Among them, we found the NR4A nuclear receptor family NR4A1, NR4A2, and NR4A3, the EGR family EGR1, EGR2, and EGR3, the IkappaB family NFKBIZ, NFKBID, and NFKBIA as a key group of the genes that possibly constitute a negative feedback loop for shutting down inflammation following NLRP3 inflammasome activation. By molecular network analysis, we identified a complex network of NLRP3 inflammasome activation-responsive genes involved in cellular development and death, and immune and inflammatory responses, where transcription factors AP-1, NR4A, and EGR serve as a hub. Thus, NLRP3 inflammasome activation-responsive genes constitute the molecular network composed of a set of negative feedback regulators for prompt resolution of inflammation.
No associated publication
Cell line, Treatment
View SamplesNasu-Hakola disease (NHD), also designated polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy (PLOSL), is a rare autosomal recessive disorder characterized by progressive presenile dementia and formation of multifocal bone cysts, caused by a loss-of-function mutation of DAP12 or TREM2. TREM2 and DAP12 constitute a receptor/adaptor complex expressed on osteoclasts, dendritic cells, macrophages, monocytes, and microglia. At present, the precise molecular mechanisms underlying development of leukoencephalopathy and bone cysts in NHD remain largely unknown. We established THP-1 human monocyte clones that stably express small interfering RNA (siRNA) targeting DAP12 for serving as a cellular model of NHD. Genome-wide transcriptome analysis identified a set of 22 genes consistently downregulated in DAP12 knockdown cells. They constituted the molecular network closely related to the network defined by cell-to-cell signaling and interaction, hematological system development and function, and inflammatory response, where NF-kappaB acts as a central regulator. These results suggest that a molecular defect of DAP12 in human monocytes deregulates the gene network pivotal for maintenance of myeloid cell function in NHD.
Gene expression profile of THP-1 monocytes following knockdown of DAP12, a causative gene for Nasu-Hakola disease.
Specimen part, Cell line
View SamplesNasu-Hakola disease (NHD), also designated polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy (PLOSL; OMIM 221770), is a rare autosomal recessive disorder, characterized by progressive presenile dementia and formation of multifocal bone cysts, caused by genetic mutations of DAP12 and TREM2, which constitute a receptor/adapter signaling complex expressed on osteoclasts, dendritic cells, macrophages, and microglia. No Japanese patients with TREM2 mutations have been reported previously. We reported three siblings affected with NHD in a Japanese family. Among them, two died of NHD during the fourth decade of life. The transcriptome was studied in the autopsized brain of one patient. We found a homozygous conversion of a single nucleotide T to C at the second position of intron 3 in the splice-donor consensus site (c.482+2T>C) of the TREM2 gene, resulting in exon 3 skipping. We identified 136 upregulated genes involved in inflammatory response and immune cell trafficking and 188 downregulated genes including a battery of GABA receptor subunits and synaptic proteins in the patients brain.
Nasu-Hakola disease with a splicing mutation of TREM2 in a Japanese family.
Sex, Age, Specimen part
View SamplesProtein malnutrition promotes hepatic steatosis, decreases insulin-like growth factor (IGF)-I production, and retards growth. In order to identify new molecules involved in such changes, we conducted DNA microarray analysis for liver samples of rats fed isoenergetic low protein diet for 8 hours, and identified fibroblast growth factor 21 (Fgf21) as one of the most strongly up-regulated genes under conditions of acute protein malnutrition (P<0.05, FDR<0.001). In addition, amino acid deprivation from the culture media increased Fgf21 mRNA levels in rat liver-derived RL-34 cells (P<0.01). Thus, it was suggested that amino acid limitation directly increases Fgf21 expression.
No associated publication
Sex, Specimen part
View SamplesTranscriptome analysis of partially degraded and fragmented RNA samples from mus musculus gut
No associated publication
Sex, Specimen part, Treatment
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