Plasma VEGF - a candidate biomarker for response to treatment with bevacizumab in HHT patients

BACKGROUND

Recurrent epistaxis is the principal symptom of hereditary hemorrhagic telangiectasia (HHT). Currently, there is no standard therapy for this condition. Bevacizumab (anti-VEGF) treatment has been under intense investigation but treatment effects vary greatly between individuals. There are currently no markers to predict anti-VEGF therapeutic response in HHT patients.

METHODS

We evaluated plasma VEGF levels in 13 HHT patients and correlated values with i) degree of epistaxis, measured by visual analog scale (VAS), epistaxis severity score (ESS), and patient bleeding diaries ii) the prevalence of extranasal manifestations, iii) the HHT subtype and iv) the treatment response to intranasal submucosal bevacizumab.

RESULTS

Plasma VEGF was elevated in all 13 HHT patients compared to reference levels and showed a moderate correlation with VAS and duration of moderate bleeding events. In patients treated with intranasal submucosal bevacizumab plasma VEGF levels showed a strong correlation with the degree of reduction of mild bleeding events and VAS.

CONCLUSIONS

The role of plasma VEGF as a potential predictive biomarker for therapeutic response to bevacizumab treatment warrants further investigation in larger prospective studies.

Erythropoietin reduces experimental autoimmune encephalomyelitis severity via neuroprotective mechanisms

Background

Treatment with erythropoietin (Epo) in experimental autoimmune encephalomyelitis (EAE), the rodent model of multiple sclerosis (MS), has consistently been shown to ameliorate disease progression and improve overall outcome. The effect has been attributed to modulation of the immune response and/or preservation of the central nervous system (CNS) tissue integrity. It remains unclear, however, if (a) Epo acts primarily in the CNS or the periphery and if (b) Epo’s beneficial effect in EAE is mainly due to maintaining CNS tissue integrity or to modulation of the immune response. If Epo acts primarily by modulating the immune system, where is this modulation required? In the periphery, the CNS or both?

Methods

To address these questions, we used two well-characterized transgenic mouse strains that constitutively overexpress recombinant human Epo (rhEpo) either systemically (tg6) or in CNS only (tg21) in a MOG-induced EAE model. We assessed clinical severity, disease progression, immunomodulation, and CNS tissue integrity, including neuronal survival.

Results

Although disease onset remained unaffected, EAE progression was alleviated in transgenic animals compared to controls with both lines performing equally well showing that expression of Epo in the periphery is not required; Epo expression in the CNS is sufficient. Immunomodulation was observed in both strains but surprisingly the profile of modulation differed substantially between strains. Modulation in the tg21 strain was limited to a reduction in macrophages in the CNS, with no peripheral immunomodulatory effects observed. In contrast, in the tg6 strain, macrophages were upregulated in the CNS, and, in the periphery of this strain, T cells and macrophages were downregulated. The lack of a consistent immunomodulatory profile across both transgenic species suggests that immunomodulation by Epo is unlikely to be the primary mechanism driving amelioration of EAE. Finally, CNS tissue integrity was affected in all strains. Although myelin appeared equally damaged in all strains, neuronal survival was significantly improved in the spinal cord of tg21 mice, indicating that Epo may ameliorate EAE predominantly by protecting neurons.

Conclusions

Our data suggests that moderate elevated brain Epo levels provide clinically significant neuroprotection in EAE without modulation of the immune response making a significant contribution.

Electronic supplementary material

The online version of this article (10.1186/s12974-017-0976-5) contains supplementary material, which is available to authorized users.

Expression of nogo-a is decreased with increasing gestational age in the human fetal brain

Nogo is a member of the reticulon family. Our understanding of the physiological functions of the Nogo-A protein has grown over the last few years, and this molecule is now recognized as one of the most important axonal regrowth inhibitors present in central nervous system (CNS) myelin. Nogo-A plays other important roles in nervous system development, epilepsy, vascular physiology, muscle pathology, stroke, inflammation, and CNS tumors. Since the exact role of Nogo-A protein in human brain development is still poorly understood, we studied its cellular and regional distribution by immunohistochemistry in the frontal lobe of 30 human fetal brains. Nogo-A was expressed in the following cortical zones: ependyma, ventricular zone, subventricular zone, intermediate zone, subplate, cortical plate, and marginal zone. The number of positive cells decreased significantly with increasing gestational age in the subplate and marginal zone. Using different antibodies, changes in isoform expression and dimerization states could be shown between various cortical zones. The results demonstrate a significant change in the expression of Nogo-A during the development of the human brain. The effects of its time- and region-specific regulation have to be further studied in detail.

Expression of TGF-beta 2 in human glioblastoma: a role in resistance to immune rejection?

Glioblastomas are among the most malignant tumours for which no curative treatment exists. A dysfunction of cellular immunity with decreased skin reactivity and lymphocyte blastogenesis has been described in patients with glioblastomas. In culture human glioblastoma cells release a factor termed glioblastoma-derived T cell suppressor factor (G-TsF) which inhibits the antigen-dependent growth of both helper and cytotoxic T cells. Purification and cloning indicated that G-TsF is a novel member of the TGF-beta family with a well-conserved mature sequence but less homology in the precursor segments. The factor was renamed TGF-beta 2. The two glioblastoma cell lines investigated expressed mRNAs for both G-TsF/TGF-beta 2 and TGF-beta 1 but only G-TsF/TGF-beta 2 protein was secreted. Neuroblastoma cells express only the mRNA for TGF-beta 1 but not the protein, nor the mRNA for G-TsF/TGF-beta 2. Recombinant G-TsF/TGF-beta 2 inhibits the generation of virus-specific cytotoxic T cells when injected into mice infected with lymphocytic choriomeningitis virus. Thus G-TsF/TGF-beta 2 might contribute to the impairment of tumour immune surveillance. Some T cell clones may escape the immunosuppressive effects of TGF-beta: ovalbumin-specific T helper cell lines that showed different degrees of susceptibility to TGF-beta contained clones which had lost receptor(s) for TGF-beta.

Botulinum toxin therapy of hemifacial spasm: comparing different therapeutic preparations

Hemifacial spasm (HFS) is characterized by involuntary irregular clonic or tonic movements of the muscles innervated by cranial nerve VII on one side of the face, and is most often a result of vascular compression of the facial nerve at the root exit zone (Muscle and Nerve 1998;21:1740). Disability associated with this disorder ranges from social embarrassment to interference with vision resulting from involuntary eye closure. Treatment of HFS most often involves botulinum toxin injections, but may also include medications and surgery. We describe treatment with the three types of botulinum toxin currently commercially available--Botox, Dysport and Myobloc/NeuroBloc.

Botulinum toxin therapy of hemifacial spasm: comparing different therapeutic preparations

Hemifacial spasm (HFS) is characterized by involuntary irregular clonic or tonic movements of the muscles innervated by cranial nerve VII on one side of the face, and is most often a result of vascular compression of the facial nerve at the root exit zone (Muscle and Nerve 1998;21:1740). Disability associated with this disorder ranges from social embarrassment to interference with vision resulting from involuntary eye closure. Treatment of HFS most often involves botulinum toxin injections, but may also include medications and surgery. We describe treatment with the three types of botulinum toxin currently commercially available--Botox, Dysport and Myobloc/NeuroBloc.

Alternative splicing of IL-24 in melanocytes by deletion of exons 3 and 5

Two novel interleukin-24 (IL-24) splice variants were identified in normal human melanocytes by sequencing cloned polymerase chain reaction (PCR) products that are not expressed in metastatic melanoma. These gene products have been generated by differential skipping of exons 3 (IL-24 delE3) and 5 (IL-24 delE5). IL-24 delE3 has limited sequence identity to the IL-24-interacting protein mda-7s, and IL-24 delE5 is homologous to IL-24.

Phantasy therapy in psychiatry: rediscovering reality in phantasy. A special treatment for in- and outpatients in general psychiatry

Phantasy Therapy is an interdisciplinary depth-psychologically oriented group therapy form with focus on the treatment of psychoses in acute and remission phases. A different theme is presented to the patients every week on two consecutive days (90 min per session), coherently, via various sensory channels. On the first day, the theme is concretely and operationally introduced by means of an object, transformed into movement in the broadest sense of the word, and experienced directly with the body. The first session ends with a story, usually a fairy tale or parable, so that the body experiences can be further realized symbolically at the cognitive-emotional level. The second session treats the same theme via repetition of the chosen story with the deeper transformation of symbols into color and form. The first day is jointly led by a psychotherapist and a movement/ dance therapist, the second day by a psychotherapist and an art therapist. Our approach understands therapy as a somatesthetic experience- and synthetic expression-oriented encounter with the patient via the therapist's empathic imaginative identification with the patient by means of a progressively orchestrated, positivizing, cognitive-emotional, theme-centered rapport. In this connection six therapeutic elements are of importance: theme, object, movement, fairy tale, artwork, symbol. Phantasy Therapy offers the patient creative freedom in a humorous and playful way within a certain therapeutic security (Amae principle) and contradicts several classical prejudices concerning the treatment of psychotic patients.

HSV-1-based amplicon particles are able to transduce cells of feline origin with genes encoding biologically functional feline IL-10 or IL-6

The most common viral disease of cats worldwide is the infection with feline herpesvirus 1 (FeHV-1). This infection may be followed by Herpetic stromal keratitis (HSK), which is supposed to have an immunopathological basis. Experiments using herpes simplex viruses (HSV) in mouse models indicated that HSK may be treated by topical application of the interleukin 10 (IL-10) gene. The objective of this study was the construction of human herpes simplex virus type 1 (HSV-1)-based amplicon vectors expressing feline interleukin genes and delivery of these genes into cells of feline origin. HSV-1-based amplicon vectors encoding either the enhanced green fluorescent protein, the feline IL-6 or the feline IL-10 under control of the HSV-1 immediate-early 4/5 promotor were constructed, packaged into amplicon particles, transduced into feline cells, and tested for RNA synthesis and biological activity. Feline cells were successfully transduced by HSV-1-based amplicon particles and RNA specific for the transgene was detected already at 2h post transduction, with a maximum at 24h. The recombinant feline IL-10 was functionally active as demonstrated by the reduction of both IL-12 p40 and interferon-gamma-mRNA production in Pansorbin stimulated feline peripheral mononuclear cells. Similarly, the recombinant feline IL-6, which was secreted into the supernatant of transduced cells, was able to support the growth of the IL-6-dependent murine B cell hybridoma 7TD1. HSV-1-based amplicon particles are able to transduce cells of feline origin with genes encoding biologically functional feline IL-10 or IL-6. It will be of high interest to study the effects of these tools in vivo.

Toxoplasma gondii infection of neurons induces neuronal cytokine and chemokine production, but gamma interferon- and tumor necrosis factor-stimulated neurons fail to inhibit the invasion and growth of T. gondii

The intracellular parasite Toxoplasma gondii has the capacity to persist in the brain within neurons. In this study we demonstrated that T. gondii infected murine cerebellar neurons in vitro and replicated within these cells. Stimulation with gamma interferon (IFN-gamma) and/or tumor necrosis factor (TNF) did not enable neurons to inhibit parasite invasion and replication. Cultured neurons constitutively produced interleukin 1 (IL-1), IL-6, macrophage inflammatory protein 1alpha (MIP-1alpha), and MIP-1beta but not transforming growth factor beta1 (TGF-beta1), IL-10, and granulocyte-macrophage colony-stimulating factor. Neuronal expression of some cytokines (IL-6, TGF-beta1) and chemokines (MIP-1beta) was regulated by infection and/or by IFN-gamma and TNF.

Molecular and cellular permeability control at the blood-brain barrier

The blood-brain barrier (BBB) is formed by brain capillary endothelial cells. These cells have at least three properties which distinguish them from their peripheral counterparts: (1) tight junctions (TJs) of extremely low permeability; (2) low rates of fluid-phase endocytosis; (3) specific transport and carrier molecules. In combination, these features restrict the nonspecific flux of ions, proteins, and other substances into the central nervous system (CNS) environment. The restriction protects neurons from harmful compositional fluctuations occurring in the blood and allows uptake of essential molecules. Breakdown of the BBB is associated with a variety of CNS disorders and results in aggravation of the condition. Restoration of the BBB is thus one strategy during therapy of CNS diseases. Its success depends on a precise knowledge of the structural and functional principles underlying BBB functionality. In this review we have tried to summarise the current knowledge of TJs, including information gained from non-neuronal systems, and describe selected mechanisms involved in permeability regulation.

Superantigen overcomes resistance of IL-6-deficient mice towards MOG-induced EAE by a TNFR1 controlled pathway

Experimental autoimmune encephalomyelitis (EAE) induced by myelin oligodendrocyte glycoprotein peptide 35-55 (MOG) leads to a chronic form of disease characterized by demyelination, inflammation and gliosis in the central nervous system (CNS). Recently IL-6 and LT alpha were found to be required for induction of the disease. The main features associated with EAE resistance of IL-6(-/-) and LT alpha(-/-) mice were reduced T cell proliferation and endothelial activation. As shown here treatment of MOG-immunized IL-6(-/-) mice with staphylococcal enterotoxin B (SEB)reversed their resistance to MOG-induced EAE. SEB failed to restore susceptibility to EAE in LT alpha(-/-) mice. The effect of SEB to induce EAE in IL-6(-/-) mice depends on TNF receptor type 1 (TNFR1) signaling because IL-6/TNF/LT alpha(-/-) and IL-6/TNFR1(-/-) are refractory to SEB. TNFR1 is involved in SEB induced trafficking of T cells into the CNS as evidenced by the failure to up-regulate VCAM-1 on CNS endothelium and lack of accumulation of V beta 8(+) T cells in the CNS of IL-6/TNFR1(-/-) mice upon immunization with MOG and treatment with SEB. The course of SEB triggered EAE in MOG immunized IL-6(-/-) mice was characterized by reduced severity and duration of clinical manifestations, which were associated with a significant drop of CNS infiltrating neutrophils and MIP-2 expression after peak disease. Taken collectively the effect of SEB to overcome EAE resistance points to a transient IL-6 independent but TNFR1 dependent proinflamatory pathway in EAE pathogenesis and suggests a crucial function for IL-6 in disease perpetuation.

Identification of a novel neuroligin in humans which binds to PSD-95 and has a widespread expression

Neuroligins, first discovered in rat brain, form a family of three synaptically enriched membrane proteins. Using reverse transcription-PCR of human brain polyadenylated RNA and extensive database searches, we identified the human homologues of the three rat neuroligins and a cDNA encoding a fourth member, which we named neuroligin 4. Neuroligin 4 has 63-73% amino acid identity with the other members of the human neuroligin family, and the same predicted domain structure. DNA database analyses, furthermore, indicated that a possible fifth neuroligin gene may be present in the human genome. Northern-blot analysis revealed expression of neuroligin 4 in heart, liver, skeletal muscle and pancreas, but barely at all in brain. Overexpression of neuroligin 4 cDNA in COS-7 cells led to the production of a 110 kDa protein. Immunofluorescence analysis demonstrated that the protein was integrated into the plasma membrane. Overexpression of cDNAs encoding neuroligin 4 and the PDZ-domain protein, PSD-95, in COS-7 cells resulted in the formation of detergent-resistant complexes. Neuroligin 4 did not bind to ZO-1, another PDZ-domain protein. Together, our data show that the human neuroligin family is composed of at least one additional member, and suggest that neuroligin 4 may also be produced outside the central nervous system.

Down-regulation of occludin expression in astrocytes by tumour necrosis factor (TNF) is mediated via TNF type-1 receptor and nuclear factor-kappaB activation

Tight junctions form the diffusion barrier of brain microcapillary endothelial cells and support cell polarity. Also astrocytes express tight junction components such as occludin, claudin-1, ZO-1 and ZO-2, but do not establish a permeability barrier. However, little is known about the function and regulation of these molecules in astrocytes. We studied the impact of tumour necrosis factor (TNF) on occludin and ZO-1 expression in astrocytes. TNF decreased occludin, but not ZO-1 expression. In brain microcapillary endothelial cells, as well as in epithelial cells, occludin expression was not influenced by TNF. Removal of TNF from astrocytes restored the basal level of occludin. Down-regulation was inhibited by caffeic acid phenethyl ester, a specific inhibitor of nuclear factor-kappaB (NF-kappaB) activation. Exposure of astrocytes isolated from mice deficient in either TNF type-1 receptor (TNFR1), TNF type-2 receptor (TNFR2), or both, respectively, revealed that down-regulation was mediated entirely by TNFR1. ZO-1, which can interact with occludin, was found to co-precipitate connexin43, but not occludin. These findings demonstrate that TNF selectively down-regulates occludin in astrocytes, but not in cells forming established tight junctions, through TNFR1 and suggest that NF-kappaB is involved as a negative regulator.

Differential effects of TNF and LTalpha in the host defense against M. bovis BCG

Signaling via TNF receptor type 1 (TNFR1) was shown to be crucial in host defense against the intracellular pathogens L. monocytogenes, M. tuberculosis and M. bovis. To investigate the function of TNF and LTalpha in host defense against M. bovis, mice double deficient for TNF and LTalpha (TNF / LTalpha (- / -)), TNF / LTalpha (- / -) mice complemented with a murine LTalpha transgene (TNF(- / -)) and LTalpha (- / -) mice were infected with BCG and the ensuing pathology was investigated. Control mice showed a normal host defense with early clearance of bacteria. The granulomatous reaction in the liver was accompanied by recruitment of activated macrophages characterized by their acid phosphatase positivity and differentiation into epithelioid cells as well as a coordinated expression of proinflammatory transcripts. In contrast, TNF / LTalpha (- / -) mice showed no comparable recruitment of activated macrophages in the liver. Furthermore, these mice showed extensive necrotic pulmonary lesions with massive growth of acid fast bacilli. Reintroduction of LTalpha as a transgene into TNF / LTalpha (- / -) mice prolonged survival but did not restore resistance to BCG. This, at least partially protective role of LTalpha was further supported by data demonstrating that LTalpha -deficient mice as well were susceptible to BCG infection. In contrast to the deleterious effect of TNF / LTalpha deficiency in BCG infection, BCG-infected TNF / LTalpha (- / -) mice were tolerant to LPS-induced shock. These results demonstrate that TNF as well as LTalpha are involved in murine host defense against BCG and that absence of TNF / LTalpha protects BCG-infected mice from LPS mediated shock.

Evidence for neuroaxonal injury in patients with proteolipid protein gene mutations

The authors used proton MRS to investigate neuropathologic correlates in nine patients with proteolipid protein (PLP) gene mutations who did not show cerebral atrophy on cranial MRI. When compared with 16 age-matched control participants, patients with PLP mutations had significant and widespread decreased brain N-acetyl aspartate, a neuronal marker. The authors conclude that PLP mutations cause neuroaxonal injury, which in turn contributes to the neurologic deficit observed in these patients.

The apical ectodermal ridge, fibroblast growth factors (FGF-2 and FGF-4) and insulin-like growth factor I (IGF-I) control the migration of epidermal melanoblasts in chicken wing buds

The role of the apical ectodermal ridge and of fibroblast growth factors FGF-2 and FGF-4 and of the insulin-like growth factor I (IGF-I) in the control of the migration of epidermal melanoblasts was investigated using quail-chicken chimeras. Wing buds of a strain of unpigmented chicken were microsurgically modified in several ways (ablation, displacement or implantation of additional apical ectodermal ridges, implantation of grafts devoid of apical ectodermal ridges, ectopic application of growth factors) and received grafts containing quail neural crest cells. The distribution of the epidermal melanoblasts which had differentiated from the quail grafts revealed that both the apical ectodermal ridge and the growth factors invariably caused the migration of epidermal melanoblasts towards them. This leads to the conclusion that the presence of the apical ectodermal ridge is the sufficient condition to direct the migration of epidermal melanoblasts within the avian embryonic wing bud. Furthermore, FGF-2 and IGF-I and to a lesser extent FGF-4 play a decisive role in directing the migration of epidermal melanoblasts within chicken wing buds and are likely to be involved in the molecular cascade by means of which the apical ectodermal ridge controls the migration of epidermal melanoblasts.

[The biosafety of the HSV-TK/GCV gene therapy in five cases of recurrent glioblastoma multiforme]

Herpes simplex virus-thymidine kinase/ganciclovir (HSV-TK/GCV) therapy was performed in five cases of recurrent glioblastoma multiforme. In the last study, the authors demonstrated response of the HSV-TK/GCV therapy against tumor progression (Adachi N, et al.: No Shinkei Geka). The aim of this study is to estimate the biosafety of in vivo HSV-TK gene transfer and GCV administration in five cases. Six parameters were analyzed sequentially up to the 6th month after the vector producer cells (VPCs) inoculation as follows; i) clinical symptom, ii) vital sign, iii) peripheral blood cell count, iv) blood biochemical analysis, v) serological test, vi) molecular biological test in peripheral leukocytes. In addition, ten systemic organs extracted from the two subjects in whom death occurred were also analyzed biologically. One case suffered from transient deterioration of left hemiparesis on the 34th day, which could be considered a probably-related but not adverse event. Serological tests detected anti-VPC antibody at the 1st month in one case and anti-vector antibody at the 1st and 4th month in another. The other examinations revealed no abnormal findings at all. These data indicate that the HSV-TK/GCV therapy might be a satisfactorily safe approach against glioblastoma multiforme.

TNFR1 signalling is critical for the development of demyelination and the limitation of T-cell responses during immune-mediated CNS disease

In this review we summarize the essential findings about the function of tumour necrosis factor (TNF) and its cognate receptors TNFR1 and TNFR2, and lymphotoxin alpha (LT-alpha) ligands in immune-mediated CNS inflammation and demyelination. The advent of homologous recombination technology in rodents provides a new method which has been used during the last 5 years and has led to insights into the pathophysiology of experimental autoimmune encephalomyelitis (EAE) in an unprecedented way. Studies with knockout mice in which genes of the TNF ligand/receptor superfamily are not expressed and studies with transgenic mice overexpressing TNF and TNFR reveal the critical role of the TNFR1 signalling pathway in the control of CNS demyelination and inflammation. These studies provide novel findings and at the same time shed light on the complex pathophysiology of EAE. Together, these findings may contribute to better understanding of EAE and open new avenues in experimental therapies for multiple sclerosis.

[The HSV-TK/GCV gene therapy in five cases of recurrent glioblastoma multiforme]

Herpes simplex virus-thymidine kinase/ganciclovir (HSV-TK/GCV) gene therapy was performed in five cases of recurrent glioblastoma multiforme. The mean age of cases, three males and two females, was 60 +/- 5 years old. All of the tumors were confirmed pathologically as glioblastoma multiforme and recurred after the initial treatments (surgery and irradiation). A total number of 1 x 10(9) vector producer cells (VPCs), which produce retroviral vectors containing the HSV-TK gene, was inoculated into the tumor-bed spaces after removal of the recurrent tumors. From the following 14th day to the 27th day, GCV was transfused 5 mg/kg i.v. twice a day. The effect of the HSV-TK/GCV gene therapy was evaluated by the Karnofsky performance scale and MRI findings sequentially, before the therapy and in the 1st, 2nd, 4th and 6th month after the VPCs inoculation. During the follow-up period of 12 months, two cases died (survival period; 8.4 and 9.9 months), whereas the other three are still alive for over 12 months (1-year survival; 60%). Karnofsky performance scale showed the maximum at the 2nd and 4th month in all cases; the mean performance rating of living cases was 80% and that of dead cases was 70%. MRI revealed progression in none of the cases until the 2nd month. These results obtained in five cases suggest that the HSV-TK/GCV gene therapy may promise a feasible approach against glioblastoma multiforme.

Interleukin-10 secretion by alveolar macrophages and monocytes in sarcoidosis

BACKGROUND

Alveolitis and the production of proinflammatory cytokines are known features of sarcoidosis. Because of the usually spontaneous resolution of alveolitis despite local secretion of mediators causing inflammation and granuloma formation, we hypothesized that downmodulating mechanisms such as anti-inflammatory cytokines might be involved in this process.

OBJECTIVE

Investigation of the secretion of the macrophage deactivating cytokines interleukin-10 (IL-10) and transforming growth factor-beta (TGF-beta) by alveolar macrophages in untreated sarcoidosis of the lung.

METHODS

Fourteen consecutive and untreated patients with pulmonary sarcoidosis and 18 volunteers underwent bronchoscopy. Alveolar macrophages (AM) were obtained by bronchoalveolar lavage and the secretion of IL-10 and TGF-beta was studied.

RESULTS

Spontaneous IL-10 production by AM was found in 6 of 14 patients and in 2 of 18 controls. The IL-10 level of lipopolysaccharide-stimulated AM was significantly higher in patients. Monocytes secreted significantly more IL-10 than AM, but there was no difference between sarcoid and control monocytes. No difference was found in the secretion of TGF-beta between patients and controls.

CONCLUSION

Increased local secretion of IL-10 - but not TGF-beta - may represent a downmodulating mechanism involved in the spontaneous resolution of alveolitis in sarcoidosis.

Antibodies to the junctional adhesion molecule cause disruption of endothelial cells and do not prevent leukocyte influx into the meninges after viral or bacterial infection

A hallmark of infectious meningitis is the invasion of leukocytes into the subarachnoid space. In experimental meningitis triggered by tumor necrosis factor-alpha and interleukin-1beta, the interaction of leukocytes with endothelial cells and the subsequent migration of the cells through the vessel wall can be inhibited by an antibody to the junctional adhesion molecule (JAM). In contrast to the cytokine-induced meningitis model, anti-JAM antibodies failed to prevent leukocyte influx into the central nervous system after infection of mice with Listeria monocytogenes or lymphocytic choriomeningitis virus. Furthermore, in bacterial meningitis, anti-JAM IgG antibodies, but not Fab fragments, caused disruption of the endothelium. Likewise complement-dependent antibody-mediated cytotoxicity was observed in cultured brain endothelial cells treated with anti-JAM IgG but not with its Fab fragment.

Treatment with nimodipine or mannitol reduces programmed cell death and infarct size following focal cerebral ischemia

The present study was conducted to evaluate the effects of nimodipine and mannitol on infarct size and on the amount of apoptosis after transient focal cerebral ischemia. Focal cerebral ischemia was induced in male Sprague-Dawley rats (weight 300-380 g) by transient occlusion of the right middle cerebral artery (MCAO) using an intraluminal thread model. All animals underwent ischemia for 2 h, followed by 24 h of reperfusion. Group I (n=16) was untreated. Group II (n=16) received 15% mannitol (1 g/kg as bolus) and group III (n=9) received 15 microg/kg/h nimodipine intravenously beginning 15 min prior to MCAO. Twenty-four hours after reperfusion, the brain was taken and sectioned in coronal slices. The slices were stained with H&E and with the transferase dUTP nick-end labeling (TUNEL) technique. Histopathological analysis revealed a significant (P<0.05) decrease in infarct size in the striatum with both drugs: mannitol (group II) 25.4+/-5.9% and nimodipine (group III) 21.5+/-11.0% versus control (group I) 34.9+/-7.0% and in the cortex 2.7+/-2.0% (group II) and 6.3+/-2.4% (group III) versus control 14.4+/-9.0% (group I). The number of apoptotic cells was statistically lower in the therapy groups (group III 9.6, group II 25.8) versus control (group I 57.9) (Mann-Whitney-Wilcoxon U-test Z>1.96, P<0.05). This study indicates that mannitol and nimodipine provide neuroprotection by preventing both the necrotic and apoptotic components of cell death after transient focal cerebral ischemia and may be effective as neuroprotective drugs for cerebrovascular surgery.

Expression and function of sialoadhesin in rat alveolar macrophages

Alveolar macrophages (Am&phi;) represent an immunologically distinct sub-population within the reticuloendothelial system. Phagocytosis and possibly antigen presentation by Am&phi; are essential components of specific and innate primary immune defence processes against inhaled material. The m&phi;-restricted sheep erythrocyte receptor sialoadhesin (Sn) is a member of the immunglobulin superfamily and binds specifically to sialic acid-containing structures such as selectins and was originally identified as the sheep erythrocyte receptor (SER) responsible for sialic acid-dependent binding of native sheep erythrocytes (SE) to resident murine bone marrow macrophages in rosetting assays. Sn expression has been demonstrated on murine and rat m&phi; in lymphatic organs and is recognised by the monoclonal antibody (mAb) ED3 in the rat. In addition, sialic acid-dependent receptor (SAR) activities that mediate rosette formation of alveolar, peritoneal, splenic and bone marrow-resident rat m&phi; with SE pretreated with gangliosides and SER-like activities between native SE and trypsinised Am&phi;, have been described. The binding activities of both SAR and Sn show similar characteristics suggesting that these molecules are closely structurally related or identical. To clarify the relationship between Sn, SAR and SER-like activities, the binding of mAb ED3 to isolated rat Am&phi; was investigated by flow cytometry and rosetting assays. It is demonstrated that rat Am&phi; express Sn and evidence is provided that SAR and SER-like activities are mediated by Sn.

Infusion of alpha-galactosidase A reduces tissue globotriaosylceramide storage in patients with Fabry disease

Fabry disease is a lysosomal storage disorder caused by a deficiency of the lysosomal enzyme alpha-galactosidase A (alpha-gal A). This enzymatic defect results in the accumulation of the glycosphingolipid globotriaosylceramide (Gb(3); also referred to as ceramidetrihexoside) throughout the body. To investigate the effects of purified alpha-gal A, 10 patients with Fabry disease received a single i.v. infusion of one of five escalating dose levels of the enzyme. The objectives of this study were: (i) to evaluate the safety of administered alpha-gal A, (ii) to assess the pharmacokinetics of i.v.-administered alpha-gal A in plasma and liver, and (iii) to determine the effect of this replacement enzyme on hepatic, urine sediment and plasma concentrations of Gb(3). alpha-Gal A infusions were well tolerated in all patients. Immunohistochemical staining of liver tissue approximately 2 days after enzyme infusion identified alpha-gal A in several cell types, including sinusoidal endothelial cells, Kupffer cells, and hepatocytes, suggesting diffuse uptake via the mannose 6-phosphate receptor. The tissue half-life in the liver was greater than 24 hr. After the single dose of alpha-gal A, nine of the 10 patients had significantly reduced Gb(3) levels both in the liver and shed renal tubular epithelial cells in the urine sediment. These data demonstrate that single infusions of alpha-gal A prepared from transfected human fibroblasts are both safe and biochemically active in patients with Fabry disease. The degree of substrate reduction seen in the study is potentially clinically significant in view of the fact that Gb(3) burden in Fabry patients increases gradually over decades. Taken together, these results suggest that enzyme replacement is likely to be an effective therapy for patients with this metabolic disorder.

Intranuclear anchoring of repetitive DNA sequences: centromeres, telomeres, and ribosomal DNA

Centromeres, telomeres, and ribosomal gene clusters consist of repetitive DNA sequences. To assess their contributions to the spatial organization of the interphase genome, their interactions with the nucleoskeleton were examined in quiescent and activated human lymphocytes. The nucleoskeletons were prepared using "physiological" conditions. The resulting structures were probed for specific DNA sequences of centromeres, telomeres, and ribosomal genes by in situ hybridization; the electroeluted DNA fractions were examined by blot hybridization. In both nonstimulated and stimulated lymphocytes, centromeric alpha-satellite repeats were almost exclusively found in the eluted fraction, while telomeric sequences remained attached to the nucleoskeleton. Ribosomal genes showed a transcription-dependent attachment pattern: in unstimulated lymphocytes, transcriptionally inactive ribosomal genes located outside the nucleolus were eluted completely. When comparing transcription unit and intergenic spacer, significantly more of the intergenic spacer was removed. In activated lymphocytes, considerable but similar amounts of both rDNA fragments were eluted. The results demonstrate that: (a) the various repetitive DNA sequences differ significantly in their intranuclear anchoring, (b) telomeric rather than centromeric DNA sequences form stable attachments to the nucleoskeleton, and (c) different attachment mechanisms might be responsible for the interaction of ribosomal genes with the nucleoskeleton.

Activation of Fas by FasL induces apoptosis by a mechanism that cannot be blocked by Bcl-2 or Bcl-x(L)

Fas activation triggers apoptosis in many cell types. Studies with anti-Fas antibodies have produced conflicting results on Fas signaling, particularly the role of the Bcl-2 family in this process. Comparison between physiological ligand and anti-Fas antibodies revealed that only extensive Fas aggregation, by membrane bound FasL or aggregated soluble FasL consistently triggered apoptosis, whereas antibodies could act as death agonists or antagonists. Studies on Fas signaling in cell lines and primary cells from transgenic mice revealed that FADD/MORT1 and caspase-8 were required for apoptosis. In contrast, Bcl-2 or Bcl-x(L) did not block FasL-induced apoptosis in lymphocytes or hepatocytes, demonstrating that signaling for cell death induced by Fas and the pathways to apoptosis regulated by the Bcl-2 family are distinct.

Occludin proteolysis and increased permeability in endothelial cells through tyrosine phosphatase inhibition

Regulation of epithelial and endothelial permeability is essential for proper function of compartmentalized organisms, and tyrosine phosphorylation plays an important role in this process. We analyzed the impact of protein tyrosine phosphatase (PTP) inhibition on the structure of endothelial junctional proteins. In human umbilical vein endothelial cells (HUVECs) the PTP inhibitors phenylarsine oxide (PAO) and pervanadate induced proteolysis of the tight junction protein occludin. Occludin proteolysis was inhibited by the metalloproteinase inhibitor 1,10-phenanthroline (PHEN), but not by inhibitors against other types of proteases. The junctional proteins ZO-1, cadherin and beta-catenin were not cleaved. Under conditions of occludin proteolysis, PAO treatment elevated permeability for FITC-dextran. Simultaneous incubation of HUVECs with PAO and PHEN inhibited the rise in permeability by more than 60%. PAO treatment lead to progressive disappearance of occludin from the cell periphery. In contrast, ZO-1, cadherin and beta-catenin retained their positions at the sites of intercellular contact. Simultaneous administration of PAO and PHEN greatly prevented the redistribution of occludin. These results demonstrate a selective cleavage of occludin by a metalloproteinase and suggest that this process can contribute to the control of paracellular permeability in endothelial cells.

Reduced antilisterial activity of TNF-deficient bone marrow-derived macrophages is due to impaired superoxide production

Mice deficient for TNF ligand and receptor type 1 have demonstrated the importance of TNF in the host defense against Listeria monocytogenes. To investigate the particular deficiency of macrophages derived from TNF/lymphotoxin (LT)-alpha(-/-) mice in antilisterial growth control, bone marrow-derived macrophages (BMDM) were used for in vitro infection experiments. After the combined treatment with IFN-gamma and lipopolysaccharide (LPS), production of NO by wild-type (wt) and TNF/LT-alpha(-/-) BMDM was induced to comparable levels, but only wt BMDM controlled L. monocytogenes growth efficiently. Nevertheless, inhibition of NO production led to a remarkable loss of antilisterial activity. This suggests that presence of NO is necessary but not sufficient for L. monocytogenes killing and that elimination of L. monocytogenes requires additional effector molecules. The LPS-inducible superoxide production of TNF/LT-alpha(-/-) BMDM was impaired. Accordingly both scavenging of superoxide and peroxynitrite led to reduced L. monocytogenes killing by wt BMDM. In addition, peroxynitrite was able to kill L. monocytogenes in vitro. Together these findings suggest that the defective host defense of TNF/LT-alpha-deficient mice against L. monocytogenes partially stems from reduced superoxide production of macrophages due to the absence of TNF and imply a function for peroxynitrite, the reaction product of NO and superoxide, in the intracellular killing of L. monocytogenes.

Treatment of experimental glioma by administration of adenoviral vectors expressing Fas ligand

Fas ligand (FasL) is a cytokine, produced by activated T cells and NK cells, that triggers apoptosis of Fas-positive target cells including human glioma cells. As shown here, in vitro infection of rat F98 and human LN18 glioma cell lines with recombinant adenovirus (rAd) expressing FasL cDNA under control of the cytomegalovirus promoter (rAd-CMV-FasL) induced striking cytotoxicity in Fas-positive glioma cell lines but not in the Fas-negative F98 glioma subline F98/ZH. The extent of FasL-mediated cytotoxic effects outranged the expectations based on expression of beta-galactosidase (beta-Gal) by F98 cells infected with a control virus expressing the lacZ gene (rAd-CMV-lacZ). The detection of FasL bioactivity in supernatants of infected cells provides evidence of a bystander mechanism involving the cytotoxic action of FasL on uninfected cells. In F98 tumor-bearing rats, infection with rAd-CMV-FasL increased the mean survival time by 50% compared with infection with rAd-CMV-lacZ or untreated controls. These data suggest that viral vector transduction of the FasL gene could be part of a successful glioma gene therapy.

Impairment of TNF-receptor-1 signaling but not fas signaling diminishes T-cell apoptosis in myelin oligodendrocyte glycoprotein peptide-induced chronic demyelinating autoimmune encephalomyelitis in mice

T-cell apoptosis in inflammatory demyelinating lesions of chronic myelin oligodendrocyte glycoprotein peptide35-55 induced autoimmune encephalomyelitis was studied in several different gene knockout mice as well as their wild-type counterparts. The gene deletions included tumor necrosis factor (TNF) alpha, lymphotoxin, TNF receptor 1 or 2, Fas-L, inducible nitric oxide synthase, perforin, and interleukin1beta-converting enzyme. Impairment of the TNF receptor 1 pathway led to a 50% reduction of T-cell apoptosis in the central nervous system lesions, whereas the other genetic deletions showed no significant effect. Our study thus identified the TNF receptor 1 signaling pathway as one mechanism responsible for the removal of T lymphocytes from inflammatory demyelinating lesions of the central nervous system.

The origin and function of soluble CD14 in experimental bacterial meningitis

Murine experimental meningitis models induced by either Escherichia coli LPS, live Streptococcus pneumoniae, or Listeria monocytogenes were used to study the origin and potential function of soluble CD14 (sCD14) in the brain during bacterial meningitis. Whereas intracerebral infection caused only a minor and/or transient increase of sCD14 levels in the serum, dramatically elevated concentrations of sCD14 were detected in the cerebrospinal fluid. Reverse-transcriptase PCR and FACS analysis of the leukocytes invading the subarachnoid compartment revealed an active amplification of CD14 transcription and concomitant surface expression. These findings were confirmed by in situ hybridization and immunohistochemical analysis. In contrast, parenchymal astrocytes and microglial cells were shown not to significantly contribute to the elevated levels of sCD14. Simultaneous intracerebral inoculation of rsCD14 and S. pneumoniae resulted in a markedly increased local cytokine response. Taken together, these data provide the first evidence that sCD14 can act as an inflammatory co-ligand in vivo. Thus, during bacterial meningitis, sCD14 is massively released by intrathecal leukocytes, and the sCD14 found in the cerebrospinal fluid can play an important role in the pathogenesis of this disease.

Severity of symptoms and demyelination in MOG-induced EAE depends on TNFR1

The individual role of tumor necrosis factor receptor 1 (TNFR1) and TNFR2 signaling in experimental autoimmune encephalomeylitis (EAE) was investigated using mice lacking TNFR1 (TNFR1-/-), TNFR2 (TNFR2-/-) as well as double receptor (TNFR1/2-/-) and double ligand (TNF/LT alpha-/-) knockout mice. In wild-type (wt) mice immunized with myelin oligodendrocyte glycoprotein (MOG) peptide 35-55 the clinical course is characterized by an acute disease onset with peak disease scores and a consecutive chronic phase lasting up to 60 days. Compared to control mice, TNF/LT alpha-deficient mice showed a significant delay in disease onset and a remarkable reduction in demyelination which was, however, associated with increased inflammation. In TNFR1-/- and TNFR1/2-/- mice, the disease course was comparable to TNF/LT alpha-deficient mice but rather monophasic and less severe at late time points. Likewise only minimal spinal cord demyelination became apparent. In contrast, the course of EAE in TNFR2-/- mice was severe and associated with remarkable demyelination. Taken together these findings define TNFR1 as crucial mediator in MOG-induced EAE and suggest a protective role for TNFR2 signaling in the clinical course of EAE.

Ex vivo malignant glioma cells are sensitive to Fas (CD95/APO-1) ligand-mediated apoptosis

Fas (also known as CD95/APO-1) is a cell surface receptor and member of the tumor necrosis factor receptor superfamily which mediates apoptosis in sensitive cells upon oligomerization by specific antibodies or by its ligand (FasL). Recently, human glioma cell lines were found to be susceptible to Fas-mediated apoptosis triggered by alpha-Fas antibodies. However, whether the Fas system can also be targeted in ex vivo high grade gliomas is at present unknown. In the present investigation, alpha-Fas antibodies and FasL were tested in short-term monolayer cultures or in colony forming assays established from freshly resected tumors of patients with anaplastic astrocytomas (WHO grade III) and glioblastoma multiforme (WHO grade IV). Anti-Fas antibodies induced only moderate apoptosis in four of the 19 tested glioma cell cultures. This contrasts FasL which induced apoptosis in all of the 19 tumor cell cultures analyzed. Mean cytotoxicity of glioma cell cultures treated for 48 h with alpha-Fas antibodies or FasL was 9.6% and 44.3%, respectively. Irrespective of whether alpha-Fas antibodies or FasL were used, pretreatment with recombinant hu (rhu) IFN-gamma and rhuTNF-alpha for 48 h did not sensitize glioma cells to Fas-mediated cytotoxicity. The long-term effect by FasL on tumor colony formation was more striking. FasL treatment resulted in more than 90% inhibition of clonal tumor cell growth of all the eight high grade gliomas analyzed. These results suggest that Fas targeting by FasL but not by alpha-Fas antibodies may provide a promising approach for locoregional glioma treatment.