Oligodendrocyte Lineage Transcription Factor Research Articles

The oligodendrocyte lineage transcription factor 2 (OLIG2) is epigenetically regulated in acute myeloid leukemia

DNA methylation differences between normal tissue and cancerous tissue resulting in differential expression of genes are a hallmark of acute myeloid leukemia (AML) and can provide malignant cells with a growth advantage via silencing of specific genes, for example, transcription factors. Oligodendrocyte lineage transcription factor 2 (OLIG2) was reported to be differentially methylated and associated with prognosis in AML and, as reported for acute lymphoblastic leukemia and malignant glioma, may play a role in malignant transformation. We report that DNA methylation of OLIG2 is associated with decreased expression of mRNA in AML cell lines and patients. Moreover, in cell lines, decreased mRNA expression also translated into decreased OLIG2 protein expression. Treatment of non-expressing cell lines PL-21 and U-937 with the demethylating agent decitabine resulted in robust re-expression of OLIG2 on mRNA and protein levels. Furthermore, stable overexpression of OLIG2 in non-expressing cell lines Kasumi-1 and U-937, using a lentiviral vector system, led to moderate growth inhibition after 4 days and resulted in signs of differentiation in U-937 cells. Interestingly, although CD34 + cells from healthy donors and 10 of 12 AML patients exhibited no protein expression, OLIG2 was expressed in two patients, both bearing the translocation t(15;17), corresponding to OLIG2 expression in NB-4 cells, also harboring t(15;17). In conclusion, we provide first evidence that OLIG2 is epigenetically regulated via DNA methylation and expressed in a subset of AML patients. OLIG2 may exert antiproliferative activity in leukemia cell lines, and its potential leukemia-suppressing role in AML warrants further investigation.

Oncogenes Activate an Autonomous Transcriptional Regulatory Circuit That Drives Glioblastoma

Efforts to identify and target glioblastoma (GBM) drivers have primarily focused on receptor tyrosine kinases (RTKs). Clinical benefits, however, have been elusive. Here, we identify an SRY-related box 2 (SOX2) transcriptional regulatory network that is independent of upstream RTKs and capable of driving glioma-initiating cells. We identified oligodendrocyte lineage transcription factor 2 (OLIG2) and zinc-finger E-box binding homeobox 1 (ZEB1), which are frequently co-expressed irrespective of driver mutations, as potential SOX2 targets. In murine glioma models, weshow that different combinations of tumor suppressor and oncogene mutations can activate Sox2, Olig2, and Zeb1 expression. We demonstrate that ectopic co-expression of the three transcription factors can transform tumor-suppressor-deficient astrocytes into glioma-initiating cells in the absence of an upstream RTK oncogene. Finally, we demonstrate that the transcriptional inhibitor mithramycin downregulates SOX2 and its target genes, resulting in markedly reduced proliferation of GBM cells invivo.

Prenatal transplantation of epidermal neural crest stem cells in malformation of cortical development mouse model.

Prenatal interventions may offer an immense opportunity in therapeutic protocols of malformations of cortical development (MCD). Epidermal neural crest stem cells (EPI-NCSCs) of the hair follicle bulge exhibit features of both embryonic and adult stem cells; these cells maintain their neurologic differentiation capability because of their neural crest origin. However, it is unknown if prenatal use of EPI-NCSCs could be beneficial in targeting methylazoxymethanol (MAM)-induced MCD, which further addressed in the present work. EPI-NCSCs were prenatally infused to the MAM-exposed mice. Thicknesses of various cerebral cortex areas as well as corpus callosum was measured; there were markedly decrease in MAM group (p < .001 vs. untreated), but a significant increase in EPI-NCSC group (p < .05 vs. MAM), except for corpus callosum. Real-time PCR analysis showed high expressions for absent, small, or homeotic 2-like protein, nestin, doublecortin (DCX), neuronal specific nuclei protein (NeuN), and glial fibrillary acidic protein (GFAP) in MAM group (p < .001 vs. untreated), except for G-protein-coupled C-X-C chemokine receptor type 4 (CXCR4) and CXC motif ligand 12 (CXCL12), whereas there were low expressions in EPI-NCSCs group (p < .01 vs. MAM). Immunohistochemistry of NeuN, GFAP, ionized calcium-binding adapter molecule (Iba1), and oligodendrocyte lineage transcription factor 2 (Olig2) was also revealed the same pattern as real-time PCR (p < .001 MAM vs. untreated, and p < .05 EPI-NCSCs vs. MAM). Our findings suggest prenatal use of EPI-NCSCs as a possible candidate for cell-based therapy of cortical injury through affecting neural markers and their relationship with glial.

Canine spinal cord glioma

Spinal cord glioma is uncommonly reported in dogs. We describe the clinicopathologic and diagnostic features of 7 cases of canine spinal cord glioma and briefly review the veterinary literature on this topic. The median age at presentation was 7.2 y. Six females and 1 male were affected and 4 dogs were brachycephalic. The clinical course lasted from 3 d to 12 wk, and clinical signs were progressive and associated with multiple suspected neuroanatomic locations in the spinal cord. Magnetic resonance imaging of 6 cases revealed T2-weighted hyperintense lesions with variable contrast enhancement in the spinal cord. All dogs had a presumptive clinical diagnosis of intraparenchymal neoplasia or myelitis based on history, advanced imaging, and cerebrospinal fluid analysis. Euthanasia was elected in all cases because of poor outcome despite anti-inflammatory or immunosuppressive treatment or because of poor prognosis at the time of diagnosis. Tumor location during autopsy ranged from C1 to L6, with no clear predilection for a specific spinal cord segment. The diagnosis was based on histopathology and the immunohistochemistry expression of glial fibrillary acidic protein, oligodendrocyte lineage transcription factor 2, 2',3'-cyclic-nucleotide 3'-phosphodiesterase, neuron-specific enolase, synaptophysin, and Ki-67. Diagnoses consisted of 4 cases of oligodendroglioma, 2 cases of gliomatosis cerebri, and 1 astrocytoma. This case series further defines the clinicopathologic features of canine spinal glioma and highlights the need for comprehensive immunohistochemistry in addition to routine histopathology to confirm the diagnosis of these tumors.

Decline in Proliferation and Immature Neuron Markers in the Human Subependymal Zone during Aging: Relationship to EGF- and FGF-Related Transcripts.

Neuroblasts exist within the human subependymal zone (SEZ); however, it is debated to what extent neurogenesis changes during normal aging. It is also unknown how precursor proliferation may correlate with the generation of neuronal and glial cells or how expression of growth factors and receptors may change throughout the adult lifespan. We found evidence of dividing cells in the human SEZ (n D 50) in conjunction with a dramatic age-related decline (21-103 years) of mRNAs indicative of proliferating cells (Ki67) and immature neurons (doublecortin). Microglia mRNA (ionized calcium-binding adapter molecule 1) increased during aging, whereas transcript levels of stem/precursor cells (glial fibrillary acidic protein delta and achaete-scute homolog 1), astrocytes (vimentin and pan-glial fibrillary acidic protein), and oligodendrocytes (oligodendrocyte lineage transcription factor 2) remained stable. Epidermal growth factor receptor (EGFR) and fibroblast growth factor 2 (FGF2) mRNAs increased throughout adulthood, while transforming growth factor alpha (TGFα), EGF, Erb-B2 receptor tyrosine kinase 4 (ErbB4) and FGF receptor 1 (FGFR1) mRNAs were unchanged across adulthood. Cell proliferation mRNA positively correlated with FGFR1 transcripts. Immature neuron and oligodendrocyte marker expression positively correlated with TGFα and ErbB4 mRNAs, whilst astrocyte transcripts positively correlated with EGF, FGF2, and FGFR1 mRNAs. Microglia mRNA positively correlated with EGF and FGF2 expression. Our findings indicate that neurogenesis in the human SEZ continues well into adulthood, although proliferation and neuronal differentiation may decline across adulthood. We suggest that mRNA expression of EGF- and FGF-related family members do not become limited during aging and may modulate neuronal and glial fate determination in the SEZ throughout human life.

Molecular mechanisms of OLIG2 transcription factor in brain cancer

Oligodendrocyte lineage transcription factor 2 (OLIG2) plays a pivotal role in glioma development. Here we conducted a comprehensive study of the critical gene regulatory networks involving OLIG2. These include the networks responsible for OLIG2 expression, its translocation to nucleus, cell cycle, epigenetic regulation, and Rho-pathway interactions. We described positive feedback loops including OLIG2: loops of epigenetic regulation and loops involving receptor tyrosine kinases. These loops may be responsible for the prolonged oncogenic activity of OLIG2. The proposed schemes for epigenetic regulation of the gene networks involving OLIG2 are confirmed by patient survival (Kaplan–Meier) curves based on the cancer genome atlas (TCGA) datasets. Finally, we elucidate the Coherent-Gene Modules (CGMs) networks—framework of OLIG2 involvement in cancer. We showed that genes interacting with OLIG2 formed eight CGMs having a set of intermodular connections. We showed also that among the genes involved in these modules the most connected hub is EGFR, then, on lower level, HSP90 and CALM1, followed by three lower levels including epigenetic genes KDM1A and NCOR1. The genes on the six upper levels of the hierarchy are involved in interconnections of all eight CGMs and organize functionally defined gene-signaling subnetworks having specific functions. For example, CGM1 is involved in epigenetic control. CGM2 is significantly related to cell proliferation and differentiation. CGM3 includes a number of interconnected helix–loop–helix transcription factors (bHLH) including OLIG2. Many of these TFs are partially controlled by OLIG2. The CGM4 is involved in PDGF-related: angiogenesis, tumor cell proliferation and differentiation. These analyses provide testable hypotheses and approaches to inhibit OLIG2 pathway and relevant feed-forward and feedback loops to be interrogated. This broad approach can be applied to other TFs.

Differential long non‑coding RNA and mRNA expression in differentiated human glioblastoma stem cells.

Differentiation of glioblastoma stem cells (GSCs) may lead to inhibition of their self‑renewing ability and tumorigenic potential, as well as increasing their sensitivity to treatment. The critical role of long non‑coding RNAs (lncRNAs) in numerous biological processes has been revealed. However, the involvement of lncRNAs in GSC differentiation remains to be elucidated. In the present study, GSCs were isolated from patient samples and differentiation was induced. Using a high‑throughput microarray, the present study identified a profile of 1,545lncRNAs and 2,729mRNAs that differed between GSCs and their non‑differentiated counterparts. To ascertain the association between the altered lncRNAs and mRNAs, a co‑expression network was constructed in which 1,087 lncRNAs and 1,928 mRNAs altered upon GSC differentiation formed a total of 19,642 lncRNA‑mRNA pairs. Based on the co‑expression network, the lncRNA functions were additionally predicted by a cis‑ or trans‑ targeting program. Furthermore, three pairs of lncRNAs and their nearby target mRNAs were selected [ENSG00000261924.1‑regulatory associated protein of MTOR complex 1, ENSG00000235427.1‑caveolin 1 and Tax1 binding protein 3 (TAX1BP3)‑purinergic receptor P2X 5 (P2RX5)‑TAX1BP3] and their expression levels were validated by reverse transcription‑quantitative polymerase chain reaction. The altered lncRNAs were also regulated by various pluripotency transcription factors (POU domain, class 3, transcription factor, sex determining region Y‑box 2, spalt‑like transcription factor 2 and oligodendrocyte lineage transcription factor 2). In conclusion, the results of the present study revealed that lncRNAs may function in GSC differentiation by regulating their target mRNAs, and a set of lncRNAs were identified as candidates for further study concerning the future treatment of GSCs.

Tetracycline-regulated expression of OLIG2 gene in human dental pulp stem cells lead to mouse sciatic nerve regeneration upon transplantation

Numerous studies have indicated dental pulp stem cells (DPSCs) potency to differentiate into several types of cell lineages. Oligodendrocyte lineage transcription factor 2 (OLIG2) plays an important role in the oligodendrogenic pathway. In this study, a tetracycline (Tet)-inducible system expressing OLIG2 gene was transfected into human DPSCs to direct their differentiation toward oligodendrocyte progenitor cells (OPCs). Following induction, the expression of stage-specific markers was studied by Reverse Transcription quantitative Polymerase Chain Reaction (RT-qPCR), immunocytochemistry and western blotting. In the following, the cells were transplanted into the mouse model of local sciatic demyelination damage by lysolecithin.Recovery of lysolecithin-induced lesions in sciatic nerve was studied by treadmill exercise, von Frey filament test and hind paw withdrawal in response to a thermal stimulus. Improvement of behavioral symptoms was efficiently observed from the second week to the sixth week post-transplantation. Our findings showed that exogenous expression of the OLIG2 gene by a Tet-regulated system could be used as an efficient way to induce the differentiation of DPSCs into functional oligodendrocytes. Meanwhile, the DPSC-derived OPCs have relevant therapeutic potential in the animal model of sciatic nerve injury and therefore might represent a valuable tool for stem cell-based therapy in inflammatory and degenerative diseases of the peripheral and central nervous systems (CNSs).

Generation and isolation of oligodendrocyte progenitor cells from human pluripotent stem cells.

In the CNS, oligodendrocytes act as the myelinating cells. Oligodendrocytes have been identified to be key players in several neurodegenerative disorders. This protocol describes a robust, fast and reproducible differentiation protocol to generate human oligodendrocytes from pluripotent stem cells (PSCs) using a chemically defined, growth factor-rich medium. Within 8 d, PSCs differentiate into paired box 6-positive (PAX6(+)) neural stem cells, which give rise to OLIG2(+) progenitors by day 12. Oligodendrocyte lineage transcription factor 2-positive (OLIG2(+)) cells begin to express the transcription factor NKX2.2 around day 18, followed by SRY-box 10 (SOX10) around day 40. Oligodendrocyte progenitor cells (OPCs) that are positive for the cell surface antigen recognized by the O4 antibody (O4(+)) appear around day 50 and reach, on average, 43% of the cell population after 75 d of differentiation. O4(+) OPCs can be isolated by cell sorting for myelination studies, or they can be terminally differentiated to myelin basic protein-positive (MBP(+)) oligodendrocytes. This protocol also describes an alternative strategy for markedly reducing the length and the costs of the differentiation and generating ∼30% O4(+) cells after only 55 d of culture.

The Oligodendrocyte Lineage Transcription Factor 2 (OLIG2) Is Epigenetically Regulated in AML and Suppresses Leukemia Cell Growth

Introduction: DNA methylation differences between normal and cancer tissue that result in differential expression of genes are a hallmark of acute myeloid leukemia (AML). DNA methylation mediated silencing of specific genes, especially transcription factors, can provide a growth advantage for malignant cells. Global DNA methylation analyses have not only led to a better understanding of AML subgroups and the impact of epigenetic aberrations in leukemogenesis, but also to the identification of new epigenetically regulated genes. We and others have recently identified the oligodendrocyte lineage transcription factor 2 (OLIG2) as differentially methylated in AML cell lines compared with normal bone marrow cells.Aim of the study: With the hypothesis that OLIG2, which is not expressed in normal hematopoiesis, may play a role in cancerogenesis as shown for acute lymphoblastic leukemia (Lin et al., Cancer Res. 2005) and malignant glioma (Mehta et al., Cancer Cell 2011), we sought to further dissect the impact of OLIG2 in AML, implementing functional studies and primary samples.Results: First, in a cohort of 93 AML patients, we could confirm previous results by Kröger et al. (Blood 2008) that OLIG2 is differentially methylated: using pyrosequencing, 37 patients (39.8%) showed methylation levels > 25% (range (r): 26-79%) in the 5 CpG containing amplicon of the OLIG2 promoter region, independent of cytogenetic subgroup. In a small subset of 13 patients where expression-data was available, an inverse correlation between OLIG2 DNA methylation and mRNA expression was significant (r2=0.55, p<0.005). This observation was further supported by a highly significant inverse DNA methylation/mRNA expression correlation in 10 leukemia cell lines (r2=0.74, p< 0.002). Moreover, we could demonstrate that this inverse correlation held also true for OLIG2 protein levels in cell lines with strong expression in THP-1 and NB-4, moderate expression in HL-60 and HEL and no expression in U937, KG-1A, PL-21, Kasumi-1, K-562 and Jurkat.Interestingly, while CD 34+ cells from two healthy donors and 10 out of 12 AML patients where protein was available, showed no protein expression, OLIG2 was expressed in 2 patients, both bearing the translocation t(15;17). This corresponds well to OLIG2 expression of cell line NB-4, which also harbours t(15;17). Treatment of non-expressing cell lines PL-21 and U937 with 200 nM 5-aza-2′-deoxycytidine led to robust re-expression of OLIG2, both on mRNA and protein level, strongly implicating DNA methylation as a silencing mechanism in a subset of AML.To investigate the relationship between OLIG2 expression and AML cell growth we used a siRNA transient knock-down in OLIG2 expressing cell lines THP-1 and NB-4. While OLIG2 protein expression measured via densitometry could be strongly reduced to 38% and 45% from pre-treatment levels in THP-1 and NB-4 cells, respectively, no change on cell viability or cell growth was detected. However, stable over-expression of OLIG2 using the lentiviral-vector pLeGO-iG in Kasumi-1 cells, led to a significant growth-inhibition of 32.2% (r: 27.0-37.3%) after 5 days and a 47.7% (r: 30.7-64.6%) increase of apoptotic cells (Annexin-V-staining) as compared to control-vector transfected cells. This negative effect on cell proliferation supports our presumption that OLIG2 could act as a growth-regulator in a subgroup of AML. This could be caused by a direct interaction between OLIG2 and a cell cycle regulator or a transcription factor complex.Conclusion: We show that OLIG2 (I) is in part epigenetically regulated via DNA methylation in AML, resulting in an inverse correlation between DNA methylation and expression; (II) can be re-expressed upon demethylating treatment in cell lines, therefore making it an attractive biomarker to study in AML patients treated with demethylating agents; (III) shows antiproliferative activity in leukemia cell lines and thus should be further studied as a potential tumor suppressor in AML. DisclosuresLübbert:Cephalon / TEVA: Travel support Other.

Olig2 overexpression accelerates the differentiation of mouse embryonic stem cells into oligodendrocyte progenitor cells in vitro.

Oligodendrocyte progenitor cells (OPCs) transplantation is receiving considerable attention in the field of regenerative medicine therapy for demyelinating diseases. Although embryonic stem cells (ESCs) have been successfully induced to differentiate into OPCs with cytokines cocktails in vitro, the regulatory roles of many key transcription factors in this process are not clear. Here, we introduced oligodendrocyte lineage transcription factor 2 (Olig2), a basic helix-loop-helix transcription factor, into mouse embryonic stem cells (mESCs) to investigate its effects on the differentiation of mESCs into OPCs. The results showed that Olig2 overexpression alone did not affect pluripotency of mESCs, but in the stimulation of differentiating cocktails, Olig2 accelerated mESCs to differentiate into OPCs, shortening the induction time span from normal 21 days to 11 days. Further study demonstrated the Olig2-mESCs derived OPCs were able to differentiate into C-type natriuretic peptid (CNP) and Myelin Basic Protein (MBP) positive mature oligodendrocytes (OLs) in vitro, suggesting these induced OPCs might be favorable for myelin regeneration in vivo.

Expression alterations of genes on both neuronal and glial development in rats after developmental exposure to 6-propyl-2-thiouracil

The present study was performed to determine target gene profiles associated with pathological mechanisms of developmental neurotoxicity. For this purpose, we selected a rat developmental hypothyroidism model because thyroid hormones play an essential role in both neuronal and glial development. Region-specific global gene expression analysis was performed at postnatal day (PND) 21 on four brain regions representing different structures and functions, i.e., the cerebral cortex, corpus callosum, dentate gyrus and cerebellar vermis of rats exposed to 6-propyl-2-thiouracil in the drinking water at 3 and 10ppm from gestational day 6 to PND 21. Expression changes of gene clusters of neuron differentiation and development, cell migration, synaptic function, and axonogenesis were detected in all four regions. Characteristically, gene expression profiles suggestive of affection of ephrin signaling and glutamate transmission were obtained in multiple brain regions. Gene clusters suggestive of suppression of myelination and glial development were specifically detected in the corpus callosum and cerebral cortex. Immunohistochemically, immature astrocytes immunoreactive for vimentin and glial fibrillary acidic protein were increased, and oligodendrocytes immunoreactive for oligodendrocyte lineage transcription factor 2 were decreased in the corpus callosum. Immunoreactive intensity of myelin basic protein was also decreased in the corpus callosum and cerebral cortex. The hippocampal dentate gyrus showed downregulation of Ptgs2, which is related to synaptic activity and neurogenesis, as well as a decrease of cyclooxygenase-2-immunoreactive granule cells, suggesting an impaired synaptic function related to neurogenesis. These results suggest that multifocal brain region-specific microarray analysis can determine the affection of neuronal or glial development.

Hypothyroxinemia induced by maternal mild iodine deficiency impairs hippocampal myelinated growth in lactational rats.

Hypothyroxinemia induced by maternal mild iodine deficiency causes neurological deficits and impairments of brain function in offspring. Hypothyroxinemia is prevalent in developing and developed countries alike. However, the mechanism underlying these deficits remains less well known. Given that the myelin plays an important role in learning and memory function, we hypothesize that hippocampal myelinated growth may be impaired in rat offspring exposed to hypothyroxinemia induced by maternal mild iodine deficiency. To test this hypothesis, the female Wistar rats were used and four experimental groups were prepared: (1) control; (2) maternal mild iodine deficiency diet inducing hypothyroxinemia; (3) hypothyroidism induced by maternal severe iodine deficiency diet; (4) hypothyroidism induced by maternal methimazole water. The rats were fed the diet from 3 months before pregnancy to the end of lactation. Our results showed that the physiological changes occuring in the hippocampal myelin were altered in the mild iodine deficiency group as indicated by the results of immunofluorescence of myelin basic proteins on postnatal day 14 and postnatal day 21. Moreover, hypothyroxinemia reduced the expressions of oligodendrocyte lineage transcription factor 2 and myelin-related proteins in the treatments on postnatal day 14 and postnatal day 21. Our data suggested that hypothyroxinemia induced by maternal mild iodine deficiency may impair myelinated growth of the offspring.

Achievement of three year remission in a case of aggressive glioblastoma using a multidisciplinary treatment strategy: A case report.

Glioblastoma (GB) is the most common type of malignant tumor of the central nervous system and, despite extensive research, its prognosis is poor. Although recent advances have been made in the treatment of GB with aggressive resection combined with radiochemotherapy, more than three-quarters of GB patients succumb to the disease within two years. The current study presents a highly aggressive case of small cell GB as diagnosed by histological features and immunohistochemistry for vimentin, glial fibrillary acidic protein, oligodendrocyte lineage transcription factor 2, isocitrate dehydrogenase 1-R132H and p53. The patient was treated using a multidisciplinary treatment strategy, which included temozolomide, CyberKnife radiotherapy and autologous formalin-fixed tumor vaccination. In addition, the patient developed radiation necrosis, which was treated with bevacizumab. In conclusion, three years following the initial diagnosis, the patient continues to experience a successful clinical course, and the observations of the current study demonstrate that a multidisciplinary treatment strategy may be effective for the treatment of aggressive GB.

Derivation of Pre-oligodendrocytes from Human Endometrial Stromal Cells by Using Overexpression of MicroRNA 338

MicroRNAs have a critical role in oligodendrocyte development including cell proliferation, differentiation, and myelin formation. MicroRNA 338 (miR-338) is necessary to promote oligodendrocyte differentiation by repressing negative regulators of oligodendrocyte differentiation. Oligodendrocytes (OLs) are responsible for myelin sheath synthesis around nerve fibers in the central nervous system (CNS) that form the myelin sheath of axons. Human endometrial-derived stromal cells (hEnSCs) are a new source of mesenchymal-like stem cells for cell replacement therapy. The hEnSCs, after treating with fibroblast growth factor 2/epidermal growth factor (20 ng/mL) and platelet-derived growth factor (PDGF)-AA (10 ng/mL) for 12 days, were divided in two groups: in the first group, the cells were treated by triiodothyronine (T3), and in the second group, the cells were infected by miR-338-green fluorescent protein-expressing lentiviruses. Six days after infection, the cells were collected and analyzed for the expression of stage-specific markers Nestin, microtubule-associated protein 2, neurofilament-L, oligodendrocyte lineage transcription factor, SRY-box containing gene 10, PDGF receptor alpha, 2',3'-cyclic nucleotide 3' phosphodiesterase, A2B5, O4, and myelin basic protein by immunocytochemistry and quantitative reverse transcription PCR. Result showed that in the infected cells, the expression of pre-oligodendrocyte markers was higher than that of T3-treated cells. The EnSCs can differentiate to oligodendrocyte cells by the overexpression of miR-338, and these cells can be used as a unique source for cell therapy of neurodegenerative disease.

New methods for inducing the differentiation of amniotic-derived mesenchymal stem cells into motor neuron precursor cells

Our study investigates the differentiation of amniotic-derived mesenchymal stem cells (ADMSCs) into motor neuron (MN) precursor cells induced by a combination of extracellular matrix (ECM) and multi-cell factors. Membrane-like ECM was made by an enzymatic and chemical extraction method and exhibited good biological compatibility. Cells in the experimental group (EG) were treated with ECM and multi-cell factors in a multi-step induction process, while the control group (CG) was treated similarly, except without ECM. In the EG, after induction, the cells formed processes that connected with neighboring cells to form a net that had directionality. In these cells, neuron-specific enolase (NSE) and synaptophysin (SYN) expression levels increased and glial fibrillary acidic protein (GFAP) expression decreased. The SYN expression in the EG cells was higher compared with those in the CG. In the CG, NSE expression increased, while the expression of Nestin and SYN did not change. These were several changes in the levels of other genes: ADMSCs at passage 1 expressed Nanog, SOX2, octamer-binding transcription factor 4 (OCT4) and Nestin. In the EG, at the beginning of induction, the expression of Nanog decreased and that of SOX2 and Nestin increased. After 2 days, the cells expressed Nestin, OCT4 and SYNIII, and after 3 days, they expressed Olig2, OCT4, Nestin, SYNII and Islet1 (ISL1). Finally, at day 6, the cells expressed Nestin, SYNI, SYNIII, ISL-1, homeobox 9 (Hb9) and oligodendrocyte lineage transcription factor 2 (Olig2). In the CG, the cells never expressed SYNI, SYNII or Hb9. Our studies therefore demonstrate that the extracted ECM was capable of promoting the maturation of synapses. Human ADMSCs are composed of multiple cell subsets, including neural progenitor cells. The multi-step induction method used in this study causes human ADMSCs to differentiate into MN precursor cells.

Candidate Pathways for Promoting Differentiation or Quiescence of Oligodendrocyte Progenitor-like Cells in Glioma

Platelet-derived growth factor receptor alpha-positive oligodendrocyte progenitor cells (OPC) located within the mature central nervous system may remain quiescent, proliferate, or differentiate into oligodendrocytes. Human glioblastoma multiforme tumors often contain rapidly proliferating oligodendrocyte lineage transcription factor 2 (Olig2)-positive cells that resemble OPCs. In this study, we sought to identify candidate pathways that promote OPC differentiation or quiescence rather than proliferation. Gene expression profiling conducted in both normal murine OPCs and highly proliferative Olig2-positive glioma cells identified all the transcripts associated with the highly proliferative state of these cells and showed that among the various cell types found within the brain, Olig2-positive tumor cells are most similar to OPCs. We then subtracted OPC transcripts found in tumor samples from those found in normal brain samples and identified 28 OPC transcripts as candidates for promoting differentiation or quiescence. Systematic analysis of human glioma data revealed that these genes have similar expression profiles in human tumors and were significantly enriched in genomic deletions, suggesting an antiproliferative role. Treatment of primary murine glioblastoma cells with agonists of one candidate gene, Gpr17, resulted in a decreased number of neurospheres. Together, our findings show that comparison of the molecular phenotype of progenitor cells in tumors to the equivalent cells in the normal brain represents a novel approach for the identification of targeted therapies.

An exploration of the oligodendrocyte lineage transcription factor 2 gene and obsessive-compulsive disorder

Zai, Gwynetha,b; Sicard, Triciaa; Burroughs, Elizac; Kennedy, James L.a,b; Richter, Margaret A.b,c Author Information

Risk variant of oligodendrocyte lineage transcription factor 2 is associated with reduced white matter integrity.

The oligodendrocyte lineage transcription factor 2 (OLIG2) regulates the genesis of oligodendrocytes, the brain cells responsible for axonal myelination. Although it has been associated with psychiatric and neurological disorders, the impact of this gene on white matter integrity has never been investigated in humans. Using diffusion tensor imaging, we examined the effect of a single nucleotide polymorphism (rs1059004) in OLIG2 previously associated with reduced gene expression, and with psychiatric disorders on fractional anisotropy in 78 healthy subjects. We found that the risk allele (A) was associated with reduced white matter integrity in the corona radiata bilaterally. This is consistent with evidence that it is a schizophrenia susceptibility gene, and suggests that it may confer increased risk through an effect on neuroanatomical connectivity.

The Discoidin domain receptor 1 gene has a functional A2RE sequence

Discoidin domain receptor 1 (DDR1) is expressed in myelin oligodendrocytes and co-localizes with myelin basic protein (MBP). Alternative splicing of DDR1 generates five isoforms designated DDR1a-e. The MBP mRNA contains an hnRNP A2 response element (A2RE) sequence that is recognized by heterogeneous nuclear ribonucleoprotein (hnRNP) A2/B1, which is responsible for transport of the MBP mRNA to oligodendrocyte processes. We hypothesized that DDR1 could have a functional A2RE sequence. By in silico analysis, we identified an A2RE-like sequence in the human DDR1 mRNA. We observed nuclear and dendrite cytoplasmic immunofluorescence, indicating that DDR1 and hnRNP A2/B1 co-localize in human oligodendrocytes and in differentiated HOG16 cells. The A2RE-like sequence of DDR1 contains the single nucleotide polymorphism rs2267641, and we found that in the human brain, the minor allele is associated with lower and higher levels DDR1b and DDR1c mRNA expression, respectively. Moreover, a positive correlation between DDR1c and the myelin genes myelin-associated glycoprotein and oligodendrocyte lineage transcription factor 2 was found. Differentiated HOG16 cells transfected with an hnRNP A2/B1 siRNA simultaneously show a decrease and an increase in the DDR1c and DDR1b mRNA expression levels, respectively, which was accompanied by a decrease in DDR1 protein levels at the cytoplasmic edges. These results suggest that the DDR1 A2RE sequence is functionally involved in the hnRNP A2/B1-mediated splicing and transport of the DDR1c mRNA.