BACKGROUNDNeural stem cells (NSCs) are a self-renewing and multipotent population of the central nervous system (CNS), which are active during development and maintain homeostasis and tissue integrity throughout life. Microglias are an immune cell population resident in the CNS, which have crucial physiological functions in the developing and adult CNS. This study aimed to investigate that whether microglia co-cultured with NSCs could promote astrogliogenesis from NSCs.

METHODSMicroglia and NSCs were co-cultured in 24-well insert plates. NSCs were plated in the bottom of the well and microglia in the insert. Fluorescent staining, Western blotting and RT-PCR were used to determine the effect of microglia on NSCs differentiation.

RESULTSCo-culture of microglia and NSCs promoted astrogliogenesis from NSCs. Several key genes, such as Notch 1, Notch 2, Notch 3, Hes 5, and NRSF were downregulated, while the critical genes Id1 and Id2 were upregulated. BMP2 and FGF2 were upregulated.

CONCLUSIONMicroglias act as a regulator of NSCs astrogliogenesis.

Animals ; Astrocytes ; cytology ; metabolism ; Basic Helix-Loop-Helix Transcription Factors ; genetics ; Blotting, Western ; Bone Morphogenetic Protein 2 ; genetics ; Cell Differentiation ; genetics ; physiology ; Cells, Cultured ; Coculture Techniques ; methods ; Fibroblast Growth Factor 2 ; genetics ; Inhibitor of Differentiation Protein 1 ; genetics ; Inhibitor of Differentiation Protein 2 ; genetics ; Microglia ; cytology ; metabolism ; Microscopy, Fluorescence ; Neural Stem Cells ; cytology ; metabolism ; Rats ; Repressor Proteins ; genetics ; Reverse Transcriptase Polymerase Chain Reaction

OBJECTIVETo investigate the expression of inhibitor of DNA differentiation/DNA binding 1 (Id1) and Id3 in endometrial carcinoma and explore their roles in regulating the proliferation, invasion, migration and adhesion of endometrial carcinoma cells in vitro.

METHODSId1 and Id3 expression in 4 fresh endometrial cancer tissue specimens and matched adjacent tissues were detected using Western blotting. Two endometrial cancer cell lines, HEC-1-B and RL-952, were both divided into 4 groups, namely the untreated group, blank virus group, promoter group and Id1/Id3 double-knockdown group, and their expressions of MMP2, CXCR4 and P21 were detected by qRT-PCR and Western blotting. The proliferation, invasion, migration and adhesion of the cells were evaluated with MTT, Transwell, wound-healing, and adhesion assays.

RESULTSEndometrial carcinoma tissues showed significantly higher Id1 and Id3 expression than the adjacent tissues (P<0.05). In the two endometrial carcinoma cell lines, Id1/Id3 double-knockdown significantly decreased MMP2 and CXCR4 expression and increased P21 expression at both mRNA and protein levels (P<0.05), and resulted in suppressed cell proliferation, invasion, migration and adhesion.

CONCLUSIONId1 and Id3 expressions are up-regulated in endometrial carcinoma to promote the proliferation, invasion, migration and adhesion of the tumor cells by increasing MMP2 and CXCR4 expression and reducing P21 expression. Therapies targeting Id1/Id3 can be a novel strategy for treatment of endometrial carcinoma.

Cell Adhesion ; Cell Line, Tumor ; Cell Movement ; Cell Proliferation ; Endometrial Neoplasms ; metabolism ; pathology ; Female ; Humans ; Inhibitor of Differentiation Protein 1 ; metabolism ; Inhibitor of Differentiation Proteins ; metabolism ; Matrix Metalloproteinase 2 ; metabolism ; Neoplasm Proteins ; metabolism ; Proto-Oncogene Proteins p21(ras) ; metabolism ; RNA Interference ; Receptors, CXCR4 ; metabolism

OBJECTIVETo verify the existence and significance of calcium/calmodulin dependent serine protein kinase/inhibitors of differentiation 1 (CASK/Id1) pathway in fibroblasts of human keloid.

METHODSImmunofluorescence laser was used to confirm CASK and Id1 protein expression and localization in fibroblasts of the keloid and normal skin. RT-PCR and Western-blot were adopted to analysis the CASK and Id1 expression and differences between keloid and normal skin fibroblasts. The natural combination of CASK and Id1 protein of keloid fibroblasts was tested by immunoprecipitation.

RESULTSCASK and Id1 protein expression were both found in fibroblast cells of keloid and normal skin under normal circumstances. Most of CASK and Id1 were distributed in the cytoplasm and nucleus of fibroblasts. The results of RT-PCR showed that the expression of CASK mRNA in the keloid group was 0.658 +/- 0.024, which was lower than that in the normal control group (1.076 +/- 0.008, t = 11.159, P < 0.05). The expression of Id1 mRNA was 0.497 +/- 0.014, which was higher than that in the normal control group (0.307 +/- 0.017, t = 15.148, P < 0.05). The results of Western-blot showed that the expression level for CASK protein in the keloid group was 0.057 +/- 0.006, which was lower than that in the normal control group (0.168 +/- 0.012, t = 13.524, P < 0.05); the expression of Id1 protein was 0.812 +/- 0.035, which was higher than that in the normal control group (0.368 +/- 0.031, t = 16.356, P < 0.05). The results of immunoprecipitation showed that Id1 could be detected in the CASK precipitate, while CASK also could be detected in the Id1 precipitate. There was a natural binding of CASK and Id1 in keloid fibroblasts.

CONCLUSIONCASK/Id1 signal pathway may be existed and involved in the proliferation of keloid fibroblasts, which is related with the occurrence of keloid.

Cell Proliferation ; genetics ; Cyclin-Dependent Kinase Inhibitor Proteins ; genetics ; metabolism ; Fibroblasts ; metabolism ; Humans ; Inhibitor of Differentiation Protein 1 ; genetics ; metabolism ; Keloid ; metabolism ; pathology ; RNA, Messenger ; metabolism ; Signal Transduction

A family of transcription factors known as Id proteins, or inhibitor of DNA binding and differentiation, is capable of regulating cell proliferation, survival and differentiation, and is often upregulated in multiple types of tumors. Due to their ability to promote self-renewal, Id proteins have been considered as oncogenes, and potential therapeutic targets in cancer models. On the contrary, certain Id proteins are reported to act as tumor suppressors in the development of Burkitt's lymphoma in humans, and hepatosplenic and innate-like T cell lymphomas in mice. The contexts and mechanisms by which Id proteins can serve in such contradictory roles to determine tumor outcomes are still not well understood. In this review, we explore the roles of Id proteins in lymphocyte development and tumorigenesis, particularly with respect to inhibition of their canonical DNA binding partners known as E proteins. Transcriptional regulation by E proteins, and their antagonism by Id proteins, act as gatekeepers to ensure appropriate lymphocyte development at key checkpoints. We re-examine the derailment of these regulatory mechanisms in lymphocytes that facilitate tumor development. These mechanistic insights can allow better appreciation of the context-dependent roles of Id proteins in cancers and improve considerations for therapy.
Carcinogenesis ; metabolism ; Cell Physiological Phenomena ; Inhibitor of Differentiation Protein 1 ; metabolism ; Lymphocytes ; physiology ; Transcription Factors ; Tumor Suppressor Proteins ; metabolism

Members of the inhibitors of differentiation (Id) family of helix-loop-helix (HLH) proteins are known to play important roles in the proliferation and differentiation of many cell types. Thyroid-stimulating hormone (TSH) regulates proliferation and differentiation by activating TSH receptor (TSHR) in thyrocytes. In this study, we found that Id2, one of the Id family proteins, is a major target for regulation by TSH in FRTL-5 thyroid cells. TSH rapidly increases the Id2 mRNA level in FRTL-5 thyroid cells but the Id2 protein showed biphasic regulatory patterns, being transiently reduced and subsequently induced by TSH treatment. Transient reduction of Id2 protein was noted within 2 hr of TSH treatment and was mediated by proteasomal degradation. Moreover, reduced Id2 expression correlated with the activity of the phosphatidylinositol 3 kinase pathway, which is activated by TSH. Although TSH increases the activity of the Id2 promoter, TSH-induced activation of this promoter was independent of c-Myc. Id2 did not alter TTF-1- and Pax-8-mediated effects on the regulation of the Tg promoter. Thus, in summary, we found that TSH regulates Id2 expression, but that Id2 does not alter the expression of thyroid-specific genes, such as Tg, in FRTL-5 thyroid cells.
1-Phosphatidylinositol 3-Kinase/metabolism ; Animals ; Cattle ; Cell Differentiation ; Cell Proliferation ; *Gene Expression Regulation ; Inhibitor of Differentiation Protein 2/metabolism ; Insulin/metabolism ; Paired Box Transcription Factors/metabolism ; Promoter Regions, Genetic ; Proto-Oncogene Proteins c-myc/metabolism ; Rats ; Thyroglobulin/metabolism ; Thyroid Gland/*cytology ; Thyrotropin/*metabolism

Multiple myeloma (MM) is an incurable heterogeneous disease derived from malignant clonal expansion of plasma cells. The evaluation of prognosis, detection of minimal residual disease (MRD) and treatment of MM are unclear for decades. Recently, Velcade and autotransplantation have been broadly applied to MM patients and achieved better outcomes, but there is yet no effective and universal marker for MRD detection in MM. Both genetic and epigene-tic aberrations play important roles in the pathogenesis and development of cancer. Our preliminary data showed that aberrant promoter methylation of zo-1 and id4 genes was correlated with their gene silencing in several types of hematological malignancies. Therefore, this study was aimed to identify the promoter methylation status of zo-1 and id4 genes in MM and their relationship with the prognosis, MRD and treatment of MM. The methylation status of zo-1 and id4 genes of MM cell lines U266, H929 and IM9 was tested by using MS-PCR; the methylation status of zo-1, id4 gene promoters in bone marrow samples of 20 MM patients and 6 healthy persons was detected by MS-PCR. The results showed that the zo-1, id4 gene in MM cell lines all were methylation positive (complete or partial methylation), the zo-1, id4 gene in samples of 5 healthy persons all were completely unmethylated. The methylation positive rate of zo-1 and id4 genes were 50% and 85% respectively, which were significantly higher than that in normal bone marrow (0%). The coverage rate of zo-1 and id4 gene methylation was 95%. There were no significant differences in the methylation status of both genes among the patients with different heavy chains, different light chains and symptoms. It is concluded that the change of zo-1, id4 genes methylation status occurs in MM patients and has specificity, which may be a new gene marker of MM, methylation analysis of zo-1 and id4 genes may be important for MRD monitoring in patients with MM.
Adult ; Aged ; Bone Marrow ; metabolism ; Cell Line, Tumor ; DNA Methylation ; Female ; Humans ; Inhibitor of Differentiation Proteins ; genetics ; metabolism ; Male ; Membrane Proteins ; genetics ; metabolism ; Middle Aged ; Multiple Myeloma ; genetics ; metabolism ; Neoplasm, Residual ; genetics ; Phosphoproteins ; genetics ; metabolism ; Zonula Occludens-1 Protein

OBJECTIVETo examine the relationship between effect of vascular endothelial growth factor (VEGF) on epithelial-myofibroblast transition (EMT) of HK-2 cells and changes in expressions of bone morphogenetic protein-7 (BMP-7) and inhibitor of DNA binding/differentiation (Id) 2, Id3.

METHODSThe cultured HK-2 cells were co-treated with transforming growth factor-beta1 (TGF-beta1) (5 ng/ml) and VEGF165 (0.1, 1, 10, 100 ng/ml), or with TGF-beta1 (5 ng/ml) and VEGF receptor-1 neutralized antibody (10 microg/ ml), and were also co-treated with TGF-beta1 (5 ng/ml) and VEGF165 (100 ng/ml) with or without activin receptor-like kinase 6 (Alk6)/Fc Chimera (2 microg/ml, to neutralize endogenous BMP-7) for 48 hours. mRNA and protein expressions of alpha-smooth muscle actin (alpha-SMA), E-cadherin, BMP-7, Id2 and Id3 of HK-2 cells were assessed with double-stain immunocytochemistry, real-time PCR and Western blot respectively.

RESULTSCompared with normal controls, alpha-SMA expression significantly increased, while E-cadherin, BMP-7, Id2, and Id3 mRNA and protein expressions markedly decreased in HK-2 cells treated with TGF-beta1 (5 ng/ml) (P < 0.05). VEGF165 interrupted TGF-beta1 induced alpha-SMA expression in a dose-dependent manner and upregulated BMP-7, Id2 mRNA and protein expressions of the cells (P < 0.05). alpha-SMA expression increased, while E-cadherin, BMP-7, and Id2 expressions decreased further in HK-2 cells co-treated with TGF-beta1 and VEGFR1 antibody compared with normal controls (P < 0.05). When endogenous BMP-7 was neutralized with Alk6/Fc Chimera in the cells co-treated with TGF-beta1 and VEGF165, alpha-SMA expression upregulated (P < 0.05), while Id2 was not changed.

CONCLUSIONSVEGF165 may partially inhibit TGF-beta1-induced EMT of HK-2 cells in vitro. This effect is related to the upregulated expressions of BMP-7 and Id2. Id2 may be upregulated directly by VEGF165, but not related to BMP-7.

Bone Morphogenetic Protein 7 ; genetics ; metabolism ; Cell Differentiation ; Cell Line ; Epithelial Cells ; cytology ; metabolism ; Gene Expression Regulation ; Humans ; Inhibitor of Differentiation Protein 2 ; genetics ; metabolism ; Inhibitor of Differentiation Proteins ; genetics ; metabolism ; Neoplasm Proteins ; genetics ; metabolism ; Transforming Growth Factor beta1 ; metabolism ; Vascular Endothelial Growth Factor A ; genetics ; metabolism

OBJECTIVETo observe the effects of thermal stress on proliferation of human vascular endothelial cells (VECs) and explore its significance.

METHODSChanges of VECs proliferation were investigated with (3)H-TdR incorporation method after ECV304 was treated at 43 degrees for 2 hours, while expressions of intercellular adhesion molecule-1 (ICAM-1), inhibitor of differentiation-1 (ID1), and P16 and P21 proteins were determined by Western Blotting.

RESULTSThe effect of inhibition of VECs growth after thermal stress was detected by (3)H-TdR incorporation experiment. Western blotting showed ICAM-1, a marker of activated endothelial cells, was increased markedly after thermal stress. Expression of ID1 protein declined gradually with increasing expressions of its downstream genes, P16 and P21 following the thermal stress.

CONCLUSIONSThermal stress could strongly activate VECs and inhibit proliferation of VECs through ID1, thus down regulating cyclin-dependent kinase inhibitors, P16 and P21, which might be an essential pathway for recovery of VECs after thermal stress.

Blotting, Western ; Cells, Cultured ; Endothelium, Vascular ; cytology ; Helix-Loop-Helix Motifs ; physiology ; Humans ; Inhibitor of Differentiation Protein 1 ; Intercellular Adhesion Molecule-1 ; metabolism ; Repressor Proteins ; Temperature ; Transcription Factors ; metabolism ; Umbilical Veins ; cytology

OBJECTIVETo screen the proteins interacting with inhibitor of differentiation 1(Id1) using yeast two-hybrid analysis in adult human lung cDNA libraries.

METHODSThe coding sequence of Id1 was amplified by PCR and cloned into the bait plasmid. The recombinant bait vector pHybLex/Zeo-Id1 was verified by restriction endonuclease digestion before transformation into the yeast strain EGY48/pSH18-34, which was tested subsequently for reporter genes Leu2 and LacZ activation. The pHybLex/Zeo-Id1 plasmid and the cDNA library plasmid were sequentially transformed into the yeast strains and screened to obtain Leu2(+) and Leu2(+)LacZ(+) clones, with the false positive clones excluded using positive and negative controls, and the plasmid of the true positive clone was sequenced and blasted for homological analysis.

RESULTSSuccessful construction of pHybLex/Zeo-Id1 was confirmed by enzyme digestion. After transformation of pHybLex/Zeo-Id1 into EGY48/pSH18-34, no specific reporter genes Leu2 and LacZ activation was found. The pHybLex/Zeo-Id1 plasmid and the cDNA library plasmid were sequentially transformed into yeast strain, and 198 Leu(+) clones and 19 Leu(+)LacZ(+) double positive clones were obtained. After elimination of the false positive clones, one true positive clone was obtained, whose plasmid analysis by sequencing and blasting indicated high homology (99.5%, 556/559) to AGGF1 (an angiogenic factor with G-patch and FHA domains 1). AGGF1 expression was confirmed in the true positive yeast cells by Western blotting.

CONCLUSIONAGGF1 is confirmed to interact with Id1 by yeast two-hybrid analysis for screening adult human lung cDNA libraries.

Adult ; Angiogenic Proteins ; genetics ; metabolism ; Cell Proliferation ; Endothelial Cells ; cytology ; metabolism ; Gene Library ; Humans ; Inhibitor of Differentiation Protein 1 ; metabolism ; Lung ; cytology ; Plasmids ; genetics ; Protein Binding ; Two-Hybrid System Techniques

OBJECTIVETo express the fusion protein of glutathione S-transferase (GST) and human Id-2 in E. coli and prepare the polyclonal antibodies against Id-2.

METHODSThe coding sequence of Id-2 gene was amplified by RT-PCR from the total RNA of breast cancer tissue. The recombinant plasmid was identified by PCR, restriction endonuclease digestion analysis and sequencing. The fusion protein GST-Id-2 expressed in E. coli following IPTG induction was purified by glutathione-agarose affinity chromatography and used to immunize rabbits to prepare the polyclonal antibodies against GST-Id-2.

RESULTSPCR, restriction endonuclease digestion and sequence analyses showed that the Id-2 gene had been correctly inserted into pGEX-6P-1 vector, and the GST-Id-2 fusion protein expressed had a relative molecular mass of approximately 40,000 as shown by SDS-PAGE. The polyclonal antibodies obtained from the rabbit sera were found to specifically react with purified Id-2 by Western blotting, ELISA and agar gel immunodiffusion (AGP).

CONCLUSIONThe prepared polyclonal antibodies against Id-2 allow effective Id-2 detection and facilitate further investigation of the structure and antigen epitope of Id-2.

Animals ; Antibodies, Monoclonal ; biosynthesis ; immunology ; Breast Neoplasms ; genetics ; Escherichia coli ; genetics ; metabolism ; Female ; Humans ; Immune Sera ; biosynthesis ; Inhibitor of Differentiation Protein 2 ; biosynthesis ; genetics ; immunology ; Rabbits ; Recombinant Proteins ; biosynthesis ; genetics