A new family with frontotemporal dementia with intronic 10+3 splice site mutation in the tau gene: neuropathology and molecular effects

Mutations in the tau gene cause familial frontotemporal dementia with parkinsonism linked to chromosome 17 characterized by filamentous tau protein deposits. Here we describe the clinical and neuropathological features of a case from a newly identified family with an intron 10+3-splice site mutation in the tau gene. The proband presented with severe personality changes and stereotyped speech followed by parkinsonian symptoms. He died at age 56 after a disease duration of approximately 6 years. At autopsy, there was marked frontotemporal degeneration with abundant tau-immunoreactive neuronal and glial inclusions widespread in the cortex and brainstem. RT-PCR analysis revealed a 3.7-fold increase of tau transcripts with exon 10, resulting in an 1.7-fold higher expression level of 4-repeat tau isoforms in soluble tau fractions when compared to control brains and exclusively 4-repeat tau isoforms in the sarcosyl-insoluble tau fractions. In accordance with the hypothesis that the overexpression leads to saturation of microtubule binding sites and an increase of unbound 4-repeat tau isoforms which assemble into filaments, the neuronal and glial inclusions in this case were exclusively composed of 4-repeat tau isoforms. The clinical and neuropathological data of this family are compared with results from the two other published families with the intron 10 + 3 mutation, the MSTD and the SOT 254 family.

Expression of the immune-tolerogenic major histocompatibility molecule HLA-G in multiple sclerosis: implications for CNS immunity

HLA-G is a non-classical major histocompatibility complex (MHC) class I antigen with highly limited tissue distribution under non-pathological conditions. Although capable of acting as a peptide-presenting molecule, its strong immune-inhibitory properties identify HLA-G as a mediator of immune tolerance with specific relevance at immune-privileged sites such as trophoblast or thymus. To assess the role of HLA-G in CNS immunity, we investigated its expression in brain specimens from patients with multiple sclerosis (n = 11), meningitis (n = 2) and Alzheimer's disease (n = 2) and non-pathological CNS controls (n = 6). Furthermore, cultured human microglial cells and CSF of patients with multiple sclerosis and controls were assessed. Furthermore, CSF from MS patients and controls, as well as cultured human microglial cells were assessed. Using several HLA-G specific mAb and immunohistochemistry, HLA-G protein was found strongly expressed in brain specimens from patients with multiple sclerosis while it was rarely detectable in the non-pathological control specimens. In multiple sclerosis brain specimens, HLA-G immunoreactivity was observed in acute plaques, in chronic active plaques, in perilesional areas as well as in normal appearing white matter. In all areas microglial cells, macrophages, and in part endothelial cells were identified as the primary cellular source of expression. HLA-G was also found in other disease entities (meningitis, Alzheimer's specimens) where expression correlated to activation and MHC class II expression on microglial cells. Importantly, ILT2, a receptor for HLA-G, was also found in multiple sclerosis brain specimens thus emphasizing the relevance of this inhibitory pathway in vivo. HLA-G mRNA and protein expression and regulation could also be corroborated on cultured human microglial cells in vitro. Further, expression of HLA-G in the CSF of multiple sclerosis patients and controls was analysed by flow cytometry and ELISA. Monocytes represented the main source of cellular HLA-G expression in the CSF. Corresponding to the observations with the tissue specimens, CSF mean levels of soluble HLA-G were significantly higher in multiple sclerosis than in non-inflammatory controls (171 +/- 31 versus 39 +/- 10 U/ml; P = 0.0001). The demonstration of HLA-G and its receptor ILT2 on CNS cells and in areas of microglia activation implicate HLA-G as a contributor to the fundamental mechanisms regulating immune reactivity in the CNS. This pathway may act as an inhibitory feedback aimed to downregulate the deleterious effects of T-cell infiltration in neuroinflammation.

Prolonged lesional expression of RhoA and RhoB following spinal cord injury

Inhibition of the small GTPase ras homology protein (Rho) or its downstream target, the Rho-associated kinase (ROCK), has been shown to promote axon regeneration and to improve functional recovery following spinal cord injury (SCI) in the adult rat. Here, we have analyzed the expression of RhoA and RhoB following spinal cord injury in order to assess whether Rho is a possible target for late pharmacological intervention. In control spinal cords, RhoA(+) cells were almost absent, whereas RhoB was localized to some ependymal cells, a few microglia, and some dissociated neurons. In injured spinal cords, RhoA(+) and RhoB(+)cells accumulated at perilesional areas and in the developing necrotic core early after injury at day 1. After reaching their maximum levels (RhoA at day 3; RhoB at day 1), RhoA(+) and RhoB(+) cell numbers remained significantly elevated until day 28. In areas remote from the lesion (> or =0.75 mm), a more discrete accumulation of RhoA(+) and RhoB(+) cells was observed, primarily in areas of ongoing Wallerian degeneration. RhoA and RhoB were predominantly expressed by polymorphonuclear granulocytes, ED1(+) microglia/macrophages, oligodendrocytes, some neurons, and swollen axons/neurites. Furthermore, expression was located to lesional, reactive astrocytes and fibroblastoid cells confined to areas of scar formation. Our experiments have determined that most RhoA(+) and RhoB(+) cells (>70%) are of mononuclear origin. The persistent presence of lesional RhoA(+) and RhoB(+) axon/neurite fibers over a period of 4 weeks after injury suggests that Rho inhibition is a putative therapeutic concept also for delayed intervention after SCI.

Death receptor-mediated apoptosis in human malignant glioma cells: modulation by the CD40/CD40L system

CD40, a TNF-R-related cell surface receptor, is shown here to be expressed by glioma cells in vitro and in vivo. Glioma cell lines expressing low levels of CD40 at the cell surface resist cytotoxic effects of CD40L. CD40 gene transfer sensitizes glioma cells to CD40L. Inhibition of protein synthesis potentiates cell death which involves CD40 clustering and caspases 8 and 3 processing. CD40-transfected LN-18 cells acquire resistance to CD95L. In contrast, subtoxic concentrations of CD40L strongly sensitize these cells for TNF-alpha-induced apoptosis. Bispecific CD40xCD95 antibodies specifically kill glioma cells, disclosing the property of endogenous CD40 to facilitate death signalling.

Disseminating anaplastic brainstem oligodendroglioma associated with allelic loss in the tumor suppressor candidate region D19S246 of chromosome 19 mimicking an inflammatory central nervous system disease in a 9-year-old boy

We report the case of a 9-year-old boy clinically presenting with severe headache, vomiting, head retroflexion, nystagmus, and ataxia. Magnetic resonance imaging showed brainstem enlargement leading to the diagnosis of an inflammatory process. In addition, the clinical picture, a monocytic cerebrospinal fluid pleocytosis with elevated protein and lactate and serum IgM antibodies to Mycoplasma pneumoniae favored this diagnosis. Subsequently, corticosteroid treatment rapidly improved clinical symptoms, and lesions declined in subsequent neuroradiological examinations. However, 2 months later, fulminant disease progression led to brain death. Final neuroradiological examination favored meningoencephalitis. The autopsy revealed brain swelling and brainstem softening with a superficial gelatinous mass extending along the spinal cord. Finally, a disseminating anaplastic oligodendroglioma with allelic loss of the D19S246 tumor suppressor candidate locus of chromosome 19 was diagnosed. To our knowledge, this is the first case of a disseminating anaplastic brainstem oligodendroglioma associated with this specific allelic loss occurring in childhood.

HLA-E protects glioma cells from NKG2D-mediated immune responses in vitro: implications for immune escape in vivo

The nonclassical MHC class I molecule HLA-E is the only known ligand for CD94/NKG2A and CD94/NKG2C expressed on NK and CD8+ alphabeta and gammadelta T cells. HLA-E may transmit either activating signals via CD94/NKG2C or inhibitory signals mediated by CD94/NKG2A. Here we show that HLA-E is expressed at mRNA and protein level in human long-term glioma cell lines, primary ex vivo polyclonal glioblastoma cell cultures and surgical glioblastoma specimens. Furthermore, immunohistochemistry revealed an enhanced in vivo expression of HLA-E in gliomas of lower grades and a massive overexpression in grade IV glioblastomas compared with normal CNS tissue. An immune-inhibitory effect of HLA-E on tumor-specific CTL has already been described. We show that siRNA-mediated silencing of HLA-E or blocking of CD94/NKG2A enables NKG2D-mediated lysis of 51Cr-labeled tumor cells by NK cells. Thus, our study provides the first evidence that expression and interaction of HLA-E on cancer cells with CD94/NKG2A expressed on lymphocytes compromises innate anti-tumor immune responses.

OPA1, associated with autosomal dominant optic atrophy, is widely expressed in the human brain

Autosomal dominant optic atrophy (adOA) is the most prevalent hereditary optic neuropathy with moderate to severe visual field loss and loss of retinal ganglion cells. The majority of cases of adOA is associated with mutations in the OPA1 gene. Northern blot analyses showed that OPA1 is expressed in all tissues examined, with the highest transcript level in the retina and in the brain. Here we addressed the cell type-specific expression of the OPA1 protein in human brain sections using immunohistochemical techniques and Western blotting. We studied OPA1 expression in normal cerebellum and various cerebral CNS tissue specimen of different areas obtained at autopsy from patients with no reported neurological symptoms or diseases and no neuropathological alterations using a polyclonal antibody raised against a C-terminal peptide of OPA1. We found OPA1 expression in somata and dendrites of neurons of the layers II-VI of the motor cortex and frontal brain. In the cerebellar cortex, OPA1 expression was detected in the Purkinje cell layer, in the granule cell layer and in the molecular layer. Double-labeling experiments showed also OPA1 expression in GFAP-positive astrocytes. Since mutations in the OPA1 gene specifically causes optic atrophy and occurrence of cerebral anomalies in adOA patients is not characteristic, this finding may suggest different cellular susceptibility of OPA1 in brain and retinal tissues.

Adult medulloblastoma: prognostic factors and response to therapy at diagnosis and at relapse

Adult medulloblastoma is a rare tumor with few retrospective studies published so far. The role of adjuvant chemotherapy or chemotherapy at relapse is unclear. This study reports therapy and outcome in all adult (>or=16 years old) medulloblastoma (n=34) and supratentorial primitive neuroectodermal tumor (PNET) patients (n=2) treated in 2 neuro-oncological centers between 1976 and 2002. The median age was 24.5 years (range 16-76). After resection, 16 patients were treated with craniospinal radiotherapy alone, 20 patients also received adjuvant chemotherapy (8 vincristine, CCNU, cisplatin; 7 methotrexate alone or methotrexate/vincristine-based polychemotherapy; 5 other protocols). Median survival in the whole cohort was 126 months (2+ - 200+months). Five-year and 10-year survival rates were 79 % and 56%. Adjuvant chemotherapy was associated with a non-significant trend to prolonged survival (relative risk (RR) 1.89; p=0.068). The median progression-free survival (PFS) after primary therapy was 83 months. At relapse, 10 of 12 evaluable patients achieved a complete response upon second-line therapy. The median survival times from first (n=17) and second relapse (n=9) were 21 months (0-67+ months; 5/17 without second relapse) and 20 months (1-29 months). Cox regression analysis revealed the infiltration of the floor of the 4(th) ventricle at diagnosis as the only therapy-independent prognostic factor (RR 0.48; p=0.03). In conclusion, adjuvant chemotherapy may prolong survival in adult medulloblastoma patients. Moreover, second-line therapy may be beneficial for these patients. As in pediatric medulloblastoma patients, primary infiltration of the floor of the 4(th) ventricle indicates a poor prognosis.

Leptomeningeal metastasis: survival and prognostic factors in 155 patients

In this single-center retrospective study, 155 consecutive patients with leptomeningeal metastasis (LM) were analyzed for the prognostic role of patient- and therapy-related variables. Ten percent of the patients received radiotherapy alone, 32% had chemotherapy alone, 31% received radiochemotherapy, 17% had supportive therapy only, and 10% were not evaluable for therapy. Chemotherapy was systemic (17%), combined systemic and intrathecal (10%), or intrathecal only (35%). Clinical improvement was noted in 41% of the patients. Overall median survival time (MST) was 4.8 months. Survival varied considerably depending on the type of primary tumor in this largest published cohort of LM patients. Univariate Cox regression analysis revealed that age >60 and elevated cerebrospinal fluid (CSF) albumin or lactate levels were therapy-independent predictors of poor survival in the entire cohort as well as in the subgroup of patients with systemic primary tumors (n=105). The assessment of three therapy-independent parameters allows to group LM patients into groups of low, intermediate, and high risk of poor survival. Moreover, the application of systemic chemotherapy was a positive prognostic factor in patients with subarachnoid lesions detected by neuroimaging (RR 1.94, p=0.001) or with extra-CNS tumor deposits (RR 1.52, p=0.05). The results of this study suggest that systemic chemotherapy alone or in combination with other therapeutic modalities may improve outcome in patients with subarachnoid tumor cell deposits detectable by neuroimaging.

Lesional RhoA+ cell numbers are suppressed by anti-inflammatory, cyclooxygenase-inhibiting treatment following subacute spinal cord injury

Inhibition of the small GTPase RhoA or its downstream target Rho-associated coiled kinase (ROCK) has been shown to promote axon regeneration and to improve functional recovery following spinal cord injury (SCI) in the adult rat. RhoA has also been implicated in delayed secondary injury pathophysiology, such as free radical formation and loss of endothelial integrity leading to edema formation. In the present report, we have analyzed the effect of the central nervous system (CNS) permissive, putatively neuroprotective, anti-inflammatory cyclooxygenase-1/-2 (COX-1/-2) inhibitor indomethacin in CNS effective dosage (2 mg/kg/day) on lesional RhoA expression following subacute spinal cord injury. In control rats receiving vehicle alone, RhoA+ cells accumulate at the lesion site (Th8). At day 3 following SCI, the RhoA+ cellular composition is composed prevailingly of microglia/macrophages and polymononuclear granulocytes, but few reactive astrocytes. In contrast, in the verum group, lesional numbers of RhoA cells were reduced by indomethacin treatment by more than 60% (P < 0.0001). Inflammation-dependent RhoA expression accessible by cyclooxygenase inhibition proposes an immune-related mechanism. Our results identify COX blockers as candidates for a safe, synergistic, adjuvant treatment option in combination with cell-specific approaches to Rho inactivation, effectively minimizing the pool of RhoA+ cells at the lesion site following SCI.

Lesional Expression of RhoA and RhoB following Traumatic Brain Injury in Humans

Inhibition of the small GTPase Rho or of its downstream target Rho-associated kinase (ROCK) has been shown to promote axon regeneration and to improve functional recovery following traumatic CNS lesions in the adult rat. In order to determine the expression pattern of RhoA and RhoB following human traumatic brain injury (TBI) and to assess whether Rho is a possible target for pharmacological intervention in humans, we investigated expression patterns of RhoA and RhoB in brain specimens from 25 patients who died after closed TBI in comparison to brain tissue derived from four neuropathologically unaffected control patients by immunohistochemistry. A highly significant lesional upregulation of both RhoA and RhoB was observed beginning several hours after the traumatic event and continuing for months after TBI. The cellular sources of both molecules included polymorphonuclear granulocytes, monocytes/macrophages, and reactive astrocytes. Additionally, expression of RhoA was also detected in neuronal cells in some of the cases. From our data, we conclude that inhibition of Rho is a promising mechanism for the development of new pharmacological interventions in human TBI. As the observed upregulation of RhoA and RhoB was still detectable months after TBI, we speculate that even delayed treatment with Rho inhibitors might be a therapeutic option.

P-glycoprotein and multidrug resistance-associated protein mediate specific patterns of multidrug resistance in malignant glioma cell lines, but not in primary glioma cells

Understanding and overcoming multidrug resistance (MDR) may be a promising strategy to develop more effective pharmacotherapies for malignant gliomas. In the present study, human malignant glioma cell lines (n=12) exhibited heterogeneous mRNA and protein expression and functional activity of the mdr gene-encoded P-glycoprotein (PGP) and MDR-associated protein (MRP). Correlation between mRNA expression, protein levels and functional activity was strong. Inhibition of PGP activity by verapamil or PSC 833 enhanced the cytotoxic effects of vincristine, doxorubicin, teniposide and taxol. Inhibition of MRP activity by indomethacin or probenecid enhanced the cytotoxic effects of vincristine, doxorubicin and teniposide. The human cerebral endothelial cell line, SV-HCEC, exhibited the strongest PGP activity of all cell lines. Five primary human glioblastomas and one anaplastic astrocytoma displayed heterogenous protein levels of PGP and MRP-1 in tumor cells and of PGP in biopsy specimens in vivo, but no functional activity of these proteins upon ex vivo culturing. These data suggest that the glioma cell line-associated MDR-type drug resistance is a result of long-term culturing and that cerebral endothelial, but not glioma cells, may contribute to MDR-type drug resistance of gliomas in vivo.

Spinal cord injury induces lesional expression of the proinflammatory and antiangiogenic cytokine EMAP II

Inflammatory cellular responses to spinal cord injury are promoted by proinflammatory messengers. We have analyzed expression of endothelial monocyte activating polypeptide II (EMAP II), a proinflammatory, antiangiogenic cytokine in rats after spinal cord injury (SCI) in comparison to normal rat spinal cords. Immunohistochemical analysis demonstrated a highly significant (p < 0.0001) accumulation of EMAP II(+) microglia/macrophages at the lesion site compared to remote areas and uninjured controls. After peaking at day 3, EMAP II(+) microglia/macrophage cell numbers declined gradually until day 28 after SCI-but still remained elevated. Further, EMAP II(+) cells formed clusters in perivascular Virchow-Robin spaces reaching a maximum at day 3. Prolonged accumulation of EMAP II(+), ED1(+) microglia/macrophages suggest a role of EMAP II in the pathophysiology of secondary injury following SCI.

Immune cell infiltration of intrinsic and metastatic intracranial tumours

BACKGROUND

Immune escape is one prerequisite for the formation of neoplasms that is reflected by the pattern of immune cell infiltration. Abundant monocytic infiltration without apparent phagocytic activity is well known in human gliomas, while other types of human intracranial tumours have not yet been investigated.

MATERIALS AND METHODS

We analysed LCA-positive lymphocytes and CD68-positive macrophages/microglia by immunohistochemistry in 67 intracranial neoplasms: 18 glioblastomas (GBM), 14 primitive neuroectodermal tumours and medulloblastomas (PNET), metastases of 9 adenocarcinomas and of 8 malignant melanomas, and 18 benign meningiomas.

RESULTS

Levels of monocytic infiltration in GBM and adenocarcinomas were higher than in PNET and meningiomas. Lymphocytes were rare in all tested tumours. No differences were found between all malignant neoplasms and benign meningiomas and between primary intracranial and metastatic tumours.

CONCLUSION

Malignancy or primary intracranial origin seem not to be major determinants of immune cell infiltration. Different patterns of cytokine production may explain the differences in single tumour entities.

Problems in fast intraoperative diagnosis in Hirschsprung's disease

Histopathological evaluation of the proximal segment in colonic resections/biopsies for Hirschsprung's disease (HD) is very important because of the strong link between proximal segment histology and postoperative outcome. Therefore, we investigated whether a recently described rapid immunohistochemical staining technique using EnVision-antibody-complex is suitable for intraoperative diagnosis during surgery in HD. Various antibodies were applied on frozen sections from 20 colonic tissue samples including aganglionic segments, segments from the transitional zone, and normally innervated bowel segments to show ganglion cells (GCs) and cholinergic fibres. Several antibodies revealed positive staining of GCs (neurofilament, synaptophysin, peripherin, neural cell adhesion molecule/NCAM/CD56). However, none of these antibodies selectively identifies GCs. Microtubuli-associated protein 2/MAP2 stained few GCs only when incubation times were extensively prolonged. The antibodies applied to determine cholinergic innervation by immunohistochemistry (Acetylcholinesterase/AChE, cholinergic Acetyltransferase/chAT) failed. Rapid immunohistochemical technique using EnVision-antibody-complex on frozen sections of the large bowel is a) suitable for detection of many diverse antigens, including several neuronal antigens, b) not helpful to prove the presence or the absence of ganglion cells with any of the antibodies applied, c) not suitable to display the cholinergic innervation and iv) therefore is not helpful to shorten the consumption time during surgery in HD.

Expression and functional activity of osteoprotegerin in human malignant gliomas

Apo2L/TRAIL-based therapy is a promising experimental approach to the treatment of human malignant gliomas. Osteoprotegerin (OPG) is a soluble decoy receptor for Apo2L/TRAIL that antagonizes Apo2L/TRAIL-induced apoptosis. High levels of OPG expressed by tumor cells might therefore abrogate the activity of exogenously added or adenovirally expessed Apo2L/TRAIL. Here we assessed the expression of OPG in human gliomas in vivo, in primary glioma cell cultures and in established glioma cell lines. Immunohistochemistry revealed weak OPG immunoreactivity in up to 5% of the tumor cells in 8 of 13 glioblastomas. Strong OPG labeling was detected in single scattered tumor cells in one of these specimens. Five glioblastomas did not express OPG. High OPG expression was found in 1 of 6 primary glioma cell cultures and in 1 of 12 established glioma cell lines, T98G. OPG released by T98G cells was biologically active in that it inhibited Apo2L/TRAIL-induced apoptosis in sensitive glioma cells. Altogether, however, these data suggest that OPG expression may not be a major pathway of glioma cell resistance to future Apo2L/TRAIL-based therapeutic approaches.

COX-3 the enzyme and the concept: steps towards highly specialized pathways and precision therapeutics?

Cyclooxygenases (COXs) catalyse the key rate-limiting step in prostanoid and thromboxane biosynthesis and are targets of non-steroidal anti-inflammatory drugs (NSAIDs). Until recently, the presence of only two isoforms-COX-1 and COX-2-remained in question because the potent anti-pyretic and analgesic effects of acetaminophen (paracetamol, tylenol ben-u-ron) could not be explained by either COX-1 or COX-2 blockades. A novel COX-1 splice variant termed COX-3, sensitive to acetaminophen, was recently discovered by Simmons et al., and is considered to play a key role in the biosynthesis of prostanoids known to be important mediators in pain and fever. Drugs that preferential block COX-1 also appear to act at COX-3. However the existence of COX-3 at the nucleotide sequence level in humans has been called to question. A functional COX-3 in humans is still to come underlining that the concept of COX-3 is still attractive. Here, we discuss some of the implications drawn from the identification of additional functional cyclooxygenase members in the generation of bioactive autacoids.

Expression of the B7-related molecule B7-H1 by glioma cells: a potential mechanism of immune paralysis

Human glioblastoma is a highly lethal tumor that is known for its immune inhibitory capabilities. B7-homologue 1 (B7-H1), a recently identified homologue of B7.1/2 (CD80/86), has been described to exert costimulatory and immune regulatory functions. We investigated the expression and the functional activity of B7-H1 in human glioma cells in vitro and in vivo. Although lacking B7.1/2 (CD80/86), all 12 glioma cell lines constitutively expressed B7-H1 mRNA and protein. Exposure to IFN-gamma strongly enhanced B7-H1 expression. Immunohistochemical analysis of malignant glioma specimens revealed strong B7-H1 expression in all 10 samples examined, whereas no B7-H1 expression could be detected on normal brain tissues. To elucidate the functional significance of glioma cell-related B7-H1 expression, we performed coculture experiments of glioma cells with alloreactive CD4+ and CD8+ T cells. Glioma-related B7-H1 was identified as a strong inhibitor of CD4+ as well as CD8+ T-cell activation as assessed by increased cytokine production (IFN-gamma, interleukin-2, and interleukin-10) and expression levels of the T-cell activation marker (CD69) in the presence of a neutralizing antibody against B7-H1 (mAb 5H1). B7-H1 expression may thus significantly influence the outcome of T-cell tumor cell interactions and represents a novel mechanism by which glioma cells evade immune recognition and destruction.

Angiogenic proteins in brains of patients who died with cerebral malaria

In cerebral malaria (CM), microvascular activation accompanies blood-brain barrier dysfunction which in turn represents the pathophysiological basis of neurological impairments in affected patients. To dissect the molecular basis of this process, we analyzed localization of proangiogenic vascular endothelial growth factor (VEGF), its receptor vascular endothelial growth factor receptor-1 (VEGFR-1, Flt-1), of downstream VEGF effectors matrix-metalloproteinase-1 (MMP-1) and connective tissue growth factor (CTGF), and of VEGF-interacting antiangiogenic thrombospondin-1 and -independent angiostatin in brains of patients who died with CM and controls by immunohistochemistry and Western blotting experiments. Most prominently, we detected more VEGF(+) astrocytes in CM patients and deposition of Flt-1 in Dürck's granulomas. MMP-1 and thrombospondin-1 accumulated in macrophages/microglial cells in Dürck's granulomas. In one CM patient, massive amounts of CTGF were detected as perivascular paracellular deposits. Angiostatin was observed in the serum of 2/7 control but in no CM patients. These data demonstrate the activation of the proangiogenic VEGF signaling cascade in patients with CM, probably reflecting compensatory mechanisms of general and focal brain hypoxia observed in these patients.

Expression and release of CD14 in astrocytic brain tumors

CD14 is a membrane-bound lipopolysaccharide receptor or, lacking the glycosylphosphatidylinositol anchor, is secreted to modulate cellular and humoral immune response by interacting directly with T and B cells. Because immunodepletion is thought to contribute to the grim prognosis of glioblastoma patients, we analyzed expression and release of CD14 in rat and human astrocytomas and glioma cell lines. Immunohistochemistry of 50 glioma biopsy specimens from low-grade diffuse astrocytoma (WHO grade II), anaplastic astrocytoma (WHO grade III) and glioblastoma (WHO grade IV), and of the C6 rat glioma model demonstrated significantly more CD14-immunoreactive macrophages/microglial cells in glioblastomas than in less malignant gliomas. In WHO grade II and III astrocytomas, only perivascular cells showed immunoreactivity with CD14. In glioblastomas, CD14-immunoreactive cells were mainly found scattered throughout the entire tumor parenchyma. Double labeling experiments demonstrated CD14 immunoreactivity predominantly in CD68-expressing macrophages/microglial cells and some glioma cells. Western blotting, reverse transcription-PCR and consecutive sequencing confirmed expression and release of CD14 by four of six analyzed glioma cell lines. These results demonstrate that CD14 is expressed, and more importantly released, from a subset of human glioma cells and infiltrating macrophages/microglial cells that may contribute to immunodepletion observed in these patients.

Effect of focal cerebral infarctions on lesional RhoA and RhoB expression

BACKGROUND

Blockade of the small GTPase Rho (ras homology protein) or of its downstream target Rho-associated kinase has been shown to promote axon regeneration in vitro and in vivo and to improve functional recovery after experimental central nervous system lesions.

OBJECTIVE

To determine the expression patterns of RhoA and RhoB after focal cerebral infarction (FCI) and to assess whether Rho is a possible target for pharmacologic intervention.

METHODS

Expression patterns of RhoA and RhoB were investigated in brain tissue specimens from 22 patients who died after FCI-clinically appearing as stroke-and were compared with those in brain tissue specimens from 4 neuropathologically unaffected controls by immunohistochemical analysis.

RESULTS

Compared with control brains, a significant lesional up-regulation of RhoA and RhoB was observed beginning 2 to 10 days after ischemia and continuing for 4 to 38 months after FCI (P<.001). The cellular sources of both molecules included polymorphonuclear granulocytes, monocytes/macrophages, and reactive astrocytes. Neuronal RhoB expression was detected in the very early stages after FCI and in some cases in the later stages adjacent to the lesion.

CONCLUSIONS

Inhibition of Rho is a promising lead for the development of new pharmacologic interventions in FCI. Because the observed up-regulation of RhoA and RhoB was still detectable months after FCI, we speculate that even delayed treatment with Rho inhibitors might be a therapeutic option.

The allograft inflammatory factor-1 in Creutzfeldt-Jakob disease brains

The allograft inflammatory factor-1 (AIF-1) is a 17-kDa IFN-gamma inducible Ca(2+)-binding EF-hand protein that is encoded within the HLA class III genomic region and is involved in immune dysfunction and smooth muscle cell activation. We used immunohistochemistry double labelling experiments to analyse the spatial distribution and cell-type-specific localization of AIF-1 in the brains of patients who died as a result of sporadic Creutzfeldt-Jakob disease (CJD) and neuropathologically unaltered controls. Significantly more AIF-1 immunoreactive macrophages/microglial cells and, interestingly, neurones were observed in CJD patients compared to controls. Western blotting confirmed more prominent AIF-1 immunoreactive bands of approximately 50 kDa in four CJD patients compared to three controls. Chaotropic SDS-PAGE of the recombinant AIF-1 resulted in almost complete reduction of the 50 kDa band and mass spectrometry revealed only AIF-1-specific tryptic protein fragments suggesting that trimerized AIF-1 is the predominant form in vivo. Finally, we analysed mechanisms of neuronal AIF-1 induction. Following H2O2 challenge, a model of general cell stress, we observed the gradual induction of AIF-1 and, more interestingly, release to the supernatant of SKNSH neurones. Parallel reverse transcriptase polymerase chain reaction and sequencing was used to confirm AIF-1 mRNA expression.

Endothelial endostatin release is induced by general cell stress and modulated by the nitric oxide/cGMP pathway

Endostatin is a 20 kDa carboxyl-terminal fragment of collagen XVIII that, when added exogenously, inhibits endothelial proliferation and migration in vitro and angiogenesis and tumor growth in vivo. Previous results showed endostatin/collagen XVIII labeling in few endothelial cells in human glioblastoma multiforme. We have now observed constitutive release of endostatin from one of four endothelial cell lines. Induction of endostatin release was observed after H2O2, an in vitro model of cell stress, CoCl2, a model of hypoxia, and by IFN-gamma challenge. Endostatin expression and release was reduced by the nitric oxide synthase inhibitors aminoguanidine and L-NAME and induced by the NO synthase-independent NO donors sodium nitroprusside (SNP) and spermine-NONO-ate. SNP-mediated endostatin induction was abrogated by the soluble guanylate cyclase inhibitor 1H-(1.2.4) oxadiazolo (4,3-A) quinoxalin-1-one. Adenoviral endostatin transduction resulted in the release of endostatin from endothelial cells and in down-regulation of iNOS (NOS2) and eNOS (NOS3), and surprisingly in a 10% induction of PCNA. These results describe the modulation of endostatin release by the NO signaling cascade and provide important new pharmacological information for the systemic induction of endogenous endostatin release by common NO donor pharmacotherapy.