Evidence for the Role of B Cells and Immunoglobulins in the Pathogenesis of Multiple Sclerosis

The pathogenesis of multiple sclerosis (MS) remains elusive. Recent reports advocate greater involvement of B cells and immunoglobulins in the initiation and propagation of MS lesions at different stages of their ontogeny. The key role of B cells and immunoglobulins in pathogenesis was initially identified by studies in which patients whose fulminant attacks of demyelination did not respond to steroids experienced remarkable functional improvement following plasma exchange. The positive response to Rituximab in Phase II clinical trials of relapsing-remitting MS confirms the role of B cells. The critical question is how B cells contribute to MS. In this paper, we discuss both the deleterious and the beneficial roles of B cells and immunoglobulins in MS lesions. We provide alternative hypotheses to explain both damaging and protective antibody responses

Sticky molecules in not-so-sticky cells

The assignment of specific roles to cell-surface proteins by standard methods can be a major problem. In the technique described below, Schneider-2 (S2) cells, an established Drosophila cell line, have been used in cell transfection and aggregation experiments. As such, they have proved to be a useful tool for the functional characterization of putative cell-adhesion molecules.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29592/1/0000681.pd

CaM kinase II isoforms are expressed at lower levels in brains of shiverer mutants

In the mammalian brain, the hippocampus is involved in memory formation and storage and has an enriched level of Ca2+/calmodulin-dependent protein kinase type II (CaM kinase II). CaM kinase II has a number of downstream targets and is shown to play a role in memory development, axonal transport, and signaling across the synapse. The shiverer mutant mouse is a knockout lacking myelin basic protein. As a result, the axons of the central nervous system (CNS) of the shiverer have no or very thin myelin sheath, neurons in their CNS have distorted shapes, and synaptic signaling is impaired. shiverer mice develop symptoms similar to those experienced by patients with multiple sclerosis. In this study, proteins from the hippocampus, cerebellum, pons, medulla, and olfactory bulbs of shiverer and wild-type mice were extracted. Western blot analysis was used to compare the expression levels of CaM kinase II in these regions of the two types of mice. Analysis shows that at least two (50 and 58-59 kDa) of the four CaM kinase II isoforms are expressed in the brain, with one isoform (50 kDa) expressed in all regions examined. shiverer brain contains a decreased level of the two isoforms of CaM kinase II, an indication that the cognitive function of these mice might also be impaired. Copyright © 2007 Humana Press Inc. All rights of any nature whatsoever are reserved

Crystal structure of tandem type III fiibronectin domains from drosophila neuroglian at 2.0 Å

We report the crystal structure of two adjacent fibronectin type III repeats from the Drosophila neural cell adhesion molecule neuroglian. Each domain consists of two antiparallel 0 sheets and is folded topologically identically to single fibronectin type III domains from the extracellular matrix proteins tenascin and fibronectin. β bulges and left-handed polyproline II helices disrupt the regular β sheet structure of both neuroglian domains. The hydrophobic interdomain interface includes a metalbinding site, presumably involved in stabilizing the relative orientation between domains and predicted by sequence comparision to be present in the vertebrate homolog molecule L1. The neuroglian domains are related by a near perfect 2-fold screw axis along the longest molecular dimension. Using this relationship, a model for arrays of tandem fibronectin type III repeats in neuroglian and other molecules is proposed

Mass Spectrometry Of Nicotinic Acetylcholine Receptors And Associated Proteins As Models For Complex Transmembrane Proteins

Studies were conducted to optimize matrix-assisted laser desorption/ionization, time-of-flight mass spectrometry (MALDI TOF MS) in analyzing the composition of nicotinic acetylcholine receptors (nAChR) from Torpedo californica electric tissue in their membrane-bound, detergent-solubilized, and affinity-purified states. Mass spectra obtained from nAChR-rich membrane fractions gave reasonably good representations of protein compositions indicated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of those same samples. Efficiency of extraction of nAChR from membranes was not markedly different for most detergents, but quality and signal size of mass spectra were clearly influenced by detergent composition and concentration, protein concentration, and MALDI matrix composition. The best spectra, allowing detection and accurate size determinations for samples containing as little as 10 fmol of pure nAChR, were obtained for samples solubilized in Triton X-100 and assayed by use of a sinapinic acid matrix. Although informative spectra could be obtained for nAChR affinity purified on α-cobratoxin (Naja naja siamensis) columns and extracted using sinapinic acid, superior spectra with much higher signal:noise were obtained if extraction media contained Triton X-100 or sodium dodecyl sulfate. nAChR subunit masses determined were similar regardless of the membrane-associated, detergent-solubilized, or affinity-purified state of the preparation. These studies illustrate how masses can be determined for nAChR subunits and for other protein components in Torpedo membrane preparations, such as RAPsyn and Na+-K+-ATPase α and β subunits. They also provide an underpinning for streamlined analysis of the composition of complex transmembrane proteins using MALDI TOF MS. © 2002 Elsevier Science (USA)

Transgenic Expression of the 3D Polymerase Inhibits Theiler's Virus Infection and Demyelination▿ †

The RNA-dependent RNA polymerase 3Dpol is required for the elongation of positive- and negative-stranded picornavirus RNA. During the course of investigating the effect of the transgenic expression of viral genes on the host immune response, we evaluated the viral load present in the host after infection. To our surprise, we found that 3D transgenic expression in genetically susceptible FVB mice led to substantially lower viral loads after infection with Theiler's murine encephalomyelitis virus (TMEV). As a result, spinal cord damage caused by chronic viral infection in the central nervous system was reduced in FVB mice that expressed 3D. This led to the preservation of large-diameter axons and motor function in these mice. The 3D transgene also lowered early viral loads when expressed in FVB-Db mice resistant to persistent TMEV infection. The protective effect of 3D transgenic expression was not altered in FVB-Rag−/−.3D mice that are deficient in T and B cells, thus ruling out a mechanism by which the overexpression of 3D enhanced the adaptive immune clearance of the virus. Understanding how endogenously overexpressed 3D polymerase inhibits viral replication may lead to new strategies for targeting therapies to all picornaviruses

A novel and selective poly (ADP-ribose) polymerase inhibitor ameliorates chemotherapy-induced painful neuropathy.

Chemotherapy-induced neuropathy is the principle dose limiting factor requiring discontinuation of many chemotherapeutic agents, including cisplatin and oxaliplatin. About 30 to 40% of patients receiving chemotherapy develop pain and sensory changes. Given that poly (ADP-ribose) polymerase (PARP) inhibition has been shown to provide neuroprotection, the current study was developed to test whether the novel PARP inhibitor compound 4a (analog of ABT-888) would attenuate pain in cisplatin and oxaliplatin-induced neuropathy in mice.An established chemotherapy-induced painful neuropathy model of two weekly cycles of 10 intraperitoneal (i.p.) injections separated by 5 days rest was used to examine the therapeutic potential of the PARP inhibitor compound 4a. Behavioral testing using von Frey, paw radiant heat, cold plate, and exploratory behaviors were taken at baseline, and followed by testing at 3, 6, and 8 weeks from the beginning of drug treatment.Cisplatin-treated mice developed heat hyperalgesia and mechanical allodynia while oxaliplatin-treated mice exhibited cold hyperalgesia and mechanical allodynia. Co-administration of 50 mg/kg or 25 mg/kg compound 4a with platinum regimen, attenuated cisplatin-induced heat hyperalgesia and mechanical allodynia in a dose dependent manner. Similarly, co-administration of 50 mg/kg compound 4a attenuated oxaliplatin-induced cold hyperalgesia and mechanical allodynia. These data indicate that administration of a novel PARP inhibitor may have important applications as a therapeutic agent for human chemotherapy-induced painful neuropathy