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Evidence for neuroprotective properties of human umbilical cord blood cells after neuronal hypoxia in vitro
Genetical Statistics and Systems Biology

Abstract (Expand)

BACKGROUND\backslashr\backslashnOne of the most promising options for treatment of stroke using adult stem cells are human umbilical cord blood (HUCB) cells that were already approved for therapeutic … efficacy in vivo. However, complexity of animal models has thus far limited the understanding of beneficial cellular mechanisms. To address the influence of HUCB cells on neuronal tissue after stroke we established and employed a human in vitro model of neuronal hypoxia using fully differentiated vulnerable SH-SY5Y cells. These cells were incubated under an oxygen-reduced atmosphere (O2\textless 1%) for 48 hours. Subsequently, HUCB mononuclear cells (MNC) were added to post-hypoxic neuronal cultures. These cultures were characterized regarding to the development of apoptosis and necrosis over three days. Based on this we investigated the therapeutic influence of HUCB MNC on the progression of apoptotic cell death. The impact of HUCB cells and hypoxia on secretion of neuroprotective and inflammatory cytokines, chemokines and expression of adhesion molecules was proved.\backslashr\backslashnRESULTS\backslashr\backslashnHypoxic cultivation of neurons initially induced a rate of 26% +/- 13% of apoptosis. Hypoxia also caused an enhanced expression of Caspase-3 and cleaved poly(ADP-ribose) polymerase (PARP). Necrosis was only detected in low amounts. Within the next three days rate of apoptosis in untreated hypoxic cultures cumulated to 85% +/- 11% (p \textless or = 0.001). Specific cytokine (VEGF) patterns also suggest anti-apoptotic strategies of neuronal cells. Remarkably, the administration of MNC showed a noticeable reduction of apoptosis rates to levels of normoxic control cultures (7% +/- 3%; p \textless or = 0.001). In parallel, clustering of administered MNC next to axons and somata of neuronal cells was observed. Furthermore, MNC caused a pronounced increase of chemokines (CCL5; CCL3 and CXCL10).\backslashr\backslashnCONCLUSION\backslashr\backslashnWe established an in vitro model of neuronal hypoxia that affords the possibility to investigate both, apoptotic neuronal cell death and neuroprotective therapies. Here we employed the therapeutic model to study neuroprotective properties of HUCB cells. We hypothesize that the neuroprotective effect of MNC was due to anti-apoptotic mechanisms related to direct cell-cell contacts with injured neuronal cells and distinct changes in neuroprotective, inflammatory cytokines as well as to the upregulation of chemokines within the co-cultures. BACKGROUND One of the most promising options for treatment of stroke using adult stem cells are human umbilical cord blood (HUCB) cells that were already approved for therapeutic efficacy in vivo. However, complexity of animal models has thus far limited the understanding of beneficial cellular mechanisms. To address the influence of HUCB cells on neuronal tissue after stroke we established and employed a human in vitro model of neuronal hypoxia using fully differentiated vulnerable SH-SY5Y cells. These cells were incubated under an oxygen-reduced atmosphere (O2\textless 1%) for 48 hours. Subsequently, HUCB mononuclear cells (MNC) were added to post-hypoxic neuronal cultures. These cultures were characterized regarding to the development of apoptosis and necrosis over three days. Based on this we investigated the therapeutic influence of HUCB MNC on the progression of apoptotic cell death. The impact of HUCB cells and hypoxia on secretion of neuroprotective and inflammatory cytokines, chemokines and expression of adhesion molecules was proved. RESULTS Hypoxic cultivation of neurons initially induced a rate of 26% +/- 13% of apoptosis. Hypoxia also caused an enhanced expression of Caspase-3 and cleaved poly(ADP-ribose) polymerase (PARP). Necrosis was only detected in low amounts. Within the next three days rate of apoptosis in untreated hypoxic cultures cumulated to 85% +/- 11% (p \textless or = 0.001). Specific cytokine (VEGF) patterns also suggest anti-apoptotic strategies of neuronal cells. Remarkably, the administration of MNC showed a noticeable reduction of apoptosis rates to levels of normoxic control cultures (7% +/- 3%; p \textless or = 0.001). In parallel, clustering of administered MNC next to axons and somata of neuronal cells was observed. Furthermore, MNC caused a pronounced increase of chemokines (CCL5; CCL3 and CXCL10). CONCLUSION We established an in vitro model of neuronal hypoxia that affords the possibility to investigate both, apoptotic neuronal cell death and neuroprotective therapies. Here we employed the therapeutic model to study neuroprotective properties of HUCB cells. We hypothesize that the neuroprotective effect of MNC was due to anti-apoptotic mechanisms related to direct cell-cell contacts with injured neuronal cells and distinct changes in neuroprotective, inflammatory cytokines as well as to the upregulation of chemokines within the co-cultures.

Authors: Susann Hau, Doreen M. Reich, Markus Scholz, Wilfried Naumann, Frank Emmrich, Manja Kamprad, Johannes Boltze

Date Published: 2008

Publication Type: Journal article

No association between systemic sclerosis and C77G polymorphism in the human PTPRC (CD45) gene
Genetical Statistics and Systems Biology

Abstract (Expand)

OBJECTIVE The functional variant C77G (rs17612648) of PTPRC (CD45) was described to confer risk for systemic sclerosis (SSc) in German Caucasians. We analyzed this association in an independent, larger …r German cohort. METHODS We genotyped 171 cases and 179 controls. Cases were subgrouped according to sex, autoantibody profiles, or clinical subsets. RESULTS No association of SSc with C77G was detected in the whole dataset, in subgroups, or in combined analyses with a previous study. CONCLUSION The results do not confirm PTPRC C77G as a general and independent risk factor for development of SSc.

Authors: Holger Kirsten, Mechthild Blume, Frank Emmrich, Nico Hunzelmann, Rudolf Mierau, Rita Rzepka, Peter Vaith, Torsten Witte, Inga Melchers, Peter Ahnert

Date Published: 2008

Publication Type: Journal article

Impact of chess training on mathematics performance and concentration ability of children with learning disabilities
Genetical Statistics and Systems Biology

Abstract

Not specified

Authors: Markus Scholz, Harald Niesch, Olaf Steffen, Baerbel Ernst, Markus Loeffler, Evelin Witruk, Hans Schwarz

Date Published: 2008

Publication Type: Journal article

Cytogenetic and molecular biological characterization of an adult medulloblastoma
Genetical Statistics and Systems Biology

Abstract (Expand)

Medulloblastoma is a malignant invasive embryonal tumor, occurring in children mainly. It is rare in adults (\textless1% of adult brain tumors), and so comprehensive cytogenetic and molecular biological … data on adult medulloblastomas are very limited. Conventional therapies provide disappointing long-term disease control, and new therapeutic options are being tested. We performed comprehensive cytogenetic analyses of an adult medulloblastoma, WHO grade IV, using trypsin-Giemsa staining (GTG-banding), multicolor fluorescence in situ hybridization (M-FISH), and locus-specific FISH, complemented by molecular karyotyping using high-density single nucleotide polymorphism (SNP) arrays. GTG-banding of 25 metaphases revealed 31 structural chromosomal aberrations, predominantly located on chromosomes 4q, 9q, 10q, 11p, and 20q, which were confirmed by M-FISH. Two novel, so far not described translocations were found: t(4;11)(q25;p15) and t(9;20)(p23;p12). GTG-banding, locus-specific FISH, and M-FISH detected numerical changes of chromosomes 8, 14, 18, 19, 20, 21, and 22. Molecular karyotyping by SNP array confirmed chromosomal changes -2p, -10q, -16q, and -Xq and revealed de novo partial uniparental disomy 1q and 9q. Applying an upcoming therapeutic approach, we found that primary medulloblastoma cells were resistant to TRAIL, a novel anticancer cytokine, but could be efficiently sensitized by cotreatment with the proteasome inhibitor bortezomib. Bortezomib-TRAIL cotreatment may serve as a powerful therapeutic option for medulloblastoma patients.

Authors: Heidrun Holland, Ronald Koschny, Wolfgang Krupp, Jürgen Meixensberger, Manfred Bauer, Ralf Schober, Holger Kirsten, Tom M. Ganten, Peter Ahnert

Date Published: 1st Oct 2007

Publication Type: Journal article

Bortezomib sensitizes primary human astrocytoma cells of WHO grades I to IV for tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis
Genetical Statistics and Systems Biology

Abstract (Expand)

PURPOSE\backslashr\backslashnMalignant gliomas are the most aggressive human brain tumors without any curative treatment. The antitumor effect of tumor necrosis factor-related apoptosis-inducing ligand … (TRAIL) in gliomas has thus far only been thoroughly established in tumor cell lines. In the present study, we investigated the therapeutic potential of TRAIL in primary human glioma cells.\backslashr\backslashnEXPERIMENTAL DESIGN\backslashr\backslashnWe isolated primary tumor cells from 13 astrocytoma and oligoastrocytoma patients of all four WHO grades of malignancy and compared the levels of TRAIL-induced apoptosis induction, long-term tumor cell survival, caspase, and caspase target cleavage.\backslashr\backslashnRESULTS\backslashr\backslashnWe established a stable culture model for isolated primary human glioma cells. In contrast to cell lines, isolated primary tumor cells from all investigated glioma patients were highly TRAIL resistant. Regardless of the tumor heterogeneity, cotreatment with the proteasome inhibitor bortezomib efficiently sensitized all primary glioma samples for TRAIL-induced apoptosis and tremendously reduced their clonogenic survival. Due to the pleiotropic effect of bortezomib-enhanced TRAIL DISC formation upon TRAIL triggering, down-regulation of cFLIP(L) and activation of the intrinsic apoptosis pathway seem to cooperatively contribute to the antitumor effect of bortezomib/TRAIL cotreatment.\backslashr\backslashnCONCLUSION\backslashr\backslashnTRAIL sensitivity of tumor cell lines is not a reliable predictor for the behavior of primary tumor cells. The widespread TRAIL resistance in primary glioma cells described here questions the therapeutic clinical benefit of TRAIL as a monotherapeutic agent. Overcoming TRAIL resistance by bortezomib cotreatment might, however, provide a powerful therapeutic option for glioma patients.

Authors: Ronald Koschny, Heidrun Holland, Jaromir Sykora, Tobias L. Haas, Martin R. Sprick, Tom M. Ganten, Wolfgang Krupp, Manfred Bauer, Peter Ahnert, Jürgen Meixensberger, Henning Walczak

Date Published: 1st Jun 2007

Publication Type: Journal article

Robustness of single-base extension against mismatches at the site of primer attachment in a clinical assay
Genetical Statistics and Systems Biology

Abstract (Expand)

DNA genotyping is important for epidemiological and clinical studies and diagnosis for individuals. Genotyping error can strongly influence the outcome of such investigations. One possible reason for … genotyping error is additional DNA sequence variation, which can lead to allelic dropout. Based on a published study where allelic dropout occurred in genotyping the cholesteryl ester transfer protein TaqIB polymorphism by a TaqMan-based method, we investigated the susceptibility of the single-base extension (SBE)-based GenoSNIP method to additional sequence variation at the primer attachment site. SBE genotyping was applied to 147 patient samples with known alleles and to synthetic SBE templates. Variables were positions of nucleotide mismatches, yield of SBE reactions, primer design, and ratio of alleles in the template. No allelic dropout occurred when genotyping the TaqIB polymorphism regardless of the reported nucleotide mismatch. Yields of SBE assays critical for allelic dropout were decreased in the presence of the reported nucleotide mismatch depending on SBE assay design. In a systematic mutation scan, only the position immediately adjacent to the polymorphism caused allelic dropout under standard conditions. Depending on SBE assay design, changes in allelic ratio due to a nucleotide mismatch were similar in appearance to changes due to sample mixture or copy number variation. In conclusion, we found the SBE genotyping assays to be relatively robust against interfering DNA variations. The importance of appropriate design and validation of assays, especially in regard to critical yields and potentially interfering nucleotide mismatches, should be emphasized particularly in clinical settings. Care should be taken when interpreting observed changes in the allelic ratio, which could be caused by nucleotide mismatches, sample mixtures, or copy number variation.

Authors: Holger Kirsten, Daniel Teupser, Jana Weissfuss, Grit Wolfram, Frank Emmrich, Peter Ahnert

Date Published: 20th Mar 2007

Publication Type: Journal article

Comprehensive cytogenetic characterization of an esthesioneuroblastoma
Genetical Statistics and Systems Biology

Abstract (Expand)

Esthesioneuroblastoma is a malignant neuroectodermal tumor originating from olfactory epithelial cells in the nasal vault. Due to the rarity of this tumor entity, cytogenetic data are very limited. … Therefore, we performed comprehensive cytogenetic analyses of an esthesioneuroblastoma, Hyam’s grade III-IV, using trypsin-Giemsa staining (GTG banding), multicolor fluorescence in situ hybridization (M-FISH), and locus-specific FISH complemented by molecular karyotyping using high-density single nucleotide polymorphism arrays. GTG banding of 25 metaphases revealed 54 structural intrachromosomal aberrations, predominantly located on 2q, 6q, 21q, and 22q, which were confirmed by FISH analysis. Interestingly, we found two novel, so far not described deletions, del(2)(q37) and del(21)(q22). Using GTG banding, locus-specific FISH, and M-FISH, we detected numeric changes of chromosomes 5, 17, 19, and 22, as well as trisomy 8 at low frequency. Applying SNP array karyotyping, we confirmed the chromosomal aberrations del(2)(q37.3), del(3)(q27.2), del(10)(q26.11), chromosomal imbalance on 17q, del(21)(q22), and revealed a number of so far unknown aberrations (gain of 2q14.3, 13q33.3, and 13q34). While the cytogenetically revealed low frequency mosaic del(6)(q22q24) was not visible using SNP array karyotyping, some of the smaller imbalances (SNP array data) could not have been detected by classic cytogenetic analysis. Therefore, our study supports the usefulness of applying complementary methods for cytogenetic analysis.

Authors: Heidrun Holland, Ronald Koschny, Wolfgang Krupp, Jürgen Meixensberger, Manfred Bauer, Holger Kirsten, Peter Ahnert

Date Published: 1st Mar 2007

Publication Type: Journal article

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