Bieber, Allan J.

Intravenous immunoglobulin (IVIG) is widely used for treatment of autoimmune neurological disorders and is currently in clinical trials as a therapy for multiple sclerosis. We have previously demonstrated that certain mouse monoclonal antibodies of the IgM isotype, promote significant remyelination when administered to mice with chronic Theiler's murine encephalomyelitis virus-induced demyelinating disease. These IgM antibodies bind to antigens expressed on oligodendrocytes. We now demonstrate that polyclonal human IgG (IVIG) and polyclonal human IgM also promote remyelination in this system. Although both polyclonal human IgG and IgM promote remyelination, IgM is more potent Polyclonal human IgM also differs from human IgG in its ability to bind strongly to antigens expressed in the CNS and by oligodendrocytes. We propose that polyclonal IgG and polyclonal IgM may function to promote remyelination by different mechanisms. IVIG may function based on its immunomodulatory activity, while the activity of IgM is critically dependent upon its reactivity with CNS antigens. This possibility has clear relevance to the use of antibodies as a therapy for multiple sclerosis, suggesting that combined treatment with antibodies exerting immunomodulatory activity, in concert with antibodies that function through direct binding to CNS antigens, may synergize to enhance the efficacy of the therapy.

Abstract Although dopamine is commonly studied for its role in incentive motivation, cognition, and various neuropsychiatric disorders, evidence from Parkinson's disease (PD) patients that present auditory deficits suggest that dopamine is also involved in central auditory processing. It has been recently discovered that the subparafascicular thalamic nucleus (SPF) sends dopaminergic projections to the inferior colliculus (IC), an important convergence hub for the ascending and descending auditory pathways. In the present study, our aim was to provide neurochemical evidence that activation of SPF neurons evokes dopamine release in the IC of anesthetized rats using fast‐scan cyclic and paired pulse voltammetry in combination with carbon fiber microelectrodes. Electrical stimulation of the SPF (60 and 90 Hz) evoked dopamine release in the IC in a frequency‐dependent manner, with higher frequencies evoking greater amplitude dopamine responses. Optogenetic‐evoked dopamine responses were similar to the effects of electrical stimulation suggesting that electrical stimulation‐evoked dopamine release was not due to nonspecific activation of fibers of passage, but rather to activation of SPF cells projecting to the IC. Selective dopamine reuptake blockade enhanced the evoked dopamine response, while selective blockade of serotonin did not, confirming the selectivity of the neurochemical recordings to dopamine. Therefore, the SPF neuronal pathway functionally mediates dopamine release in the IC and thus may be involved in auditory processing deficits associated with PD.

OBJECT Despite a promising outlook, existing intraspinal microstimulation (ISMS) techniques for restoring functional motor control after spinal cord injury are not yet suitable for use outside a controlled laboratory environment. Thus, successful application of ISMS therapy in humans will require the use of versatile chronic neurostimulation systems. The objective of this study was to establish proof of principle for wireless control of ISMS to evoke controlled motor function in a rodent model of complete spinal cord injury. METHODS The lumbar spinal cord in each of 17 fully anesthetized Sprague-Dawley rats was stimulated via ISMS electrodes to evoke hindlimb function. Nine subjects underwent complete surgical transection of the spinal cord at the T-4 level 7 days before stimulation. Targeting for both groups (spinalized and control) was performed under visual inspection via dorsal spinal cord landmarks such as the dorsal root entry zone and the dorsal median fissure. Teflon-insulated stimulating platinum-iridium microwire electrodes (50 μm in diameter, with a 30- to 60-μm exposed tip) were implanted within the ventral gray matter to an approximate depth of 1.8 mm. Electrode implantation was performed using a free-hand delivery technique (n = 12) or a Kopf spinal frame system (n = 5) to compare the efficacy of these 2 commonly used targeting techniques. Stimulation was controlled remotely using a wireless neurostimulation control system. Hindlimb movements evoked by stimulation were tracked via kinematic markers placed on the hips, knees, ankles, and paws. Postmortem fixation and staining of the spinal cord tissue were conducted to determine the final positions of the stimulating electrodes within the spinal cord tissue. RESULTS The results show that wireless ISMS was capable of evoking controlled and sustained activation of ankle, knee, and hip muscles in 90% of the spinalized rats (n = 9) and 100% of the healthy control rats (n = 8). No functional differences between movements evoked by either of the 2 targeting techniques were revealed. However, frame-based targeting required fewer electrode penetrations to evoke target movements. CONCLUSIONS Clinical restoration of functional movement via ISMS remains a distant goal. However, the technology presented herein represents the first step toward restoring functional independence for individuals with chronic spinal cord injury.

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.

Background: Cisplatin is primarily used for treatment of ovarian and testicular cancer. Oxaliplatin is the only effective treatment for metastatic colorectal cancer. Both are known to cause dose related, cumulative toxic effects on the peripheral nervous system and thirty to forty percent of cancer patients receiving these agents experience painful peripheral neuropathy. The mechanisms underlying painful platinum-induced neuropathy remain poorly understood. Previous studies have demonstrated important roles for TRPV1, TRPM8, and TRPA1 in inflammation and nerve injury induced pain. Results: In this study, using real-time, reverse transcriptase, polymerase chain reaction (RT-PCR), we analyzed the expression of TRPV1, TRPM8, and TRPA1 induced by cisplatin or oxaliplatin in vitro and in vivo. For in vitro studies, cultured E15 rat dorsal root ganglion (DRG) neurons were treated for up to 48 hours with cisplatin or oxaliplatin. For in vivo studies, trigeminal ganglia (TG) were isolated from mice treated with platinum drugs for three weeks. We show that cisplatin and oxaliplatin-treated DRG neurons had significantly increased in TRPV1, TRPA1, and TRPM8 mRNA expression. TG neurons from cisplatin treated mice had significant increases in TRPV1 and TRPA1 mRNA expression while oxaliplatin strongly induced only TRPA1. Furthermore, compared to the cisplatin-treated wild-type mice, cisplatin-treated TRPV1-null mice developed mechanical allodynia but did not exhibit enhancement of noxious heat- evoked pain responses. Immunohistochemistry studies showed that cisplatin-treated mice had no change in the proportion of the TRPV1 immunopositive TG neurons. Conclusion: These results indicate that TRPV1 and TRPA1 could contribute to the development of thermal hyperalgesia and mechanical allodynia following cisplatin-induced painful neuropathy but that TRPV1 has a crucial role in cisplatin-induced thermal hyperalgesia in vivo.

The potential for endogenous remyelination and axonal protection can be an important factor in determining disease outcome in demyelinating diseases like multiple sclerosis. In many multiple sclerosis (MS) patients CNS repair fails or is incomplete whereas in others the disease is accompanied by extensive repair of demyelinated lesions. We have described significant differences in the ability of two strains of mice to repair CNS damage following Theiler’s virus-induced demyelination: FVB/NJ (FVB) mice repair damaged myelin spontaneously and completely, whereas B10.D1-H2 q /SgJ (B10.Q) mice are deficient in the repair process. A QTL analysis was performed to identify genetic loci that differentially regulate CNS repair following chronic demyelination in these strains and two QTL were detected: one on chromosome 3 with a LOD score of 9.3 and a second on chromosome 9 with a LOD score of 14.0. The mouse genes for epidermal growth factor (EGF) and Tyk2 are encoded within the QTL on chromosomes 3 and 9, respectively. Sequence polymorphisms between the FVB and B10.Q strains at both the EGF and Tyk2 loci define functional variations consistent with roles for these genes in regulating myelin repair. EGF is a key regulator of cell growth and development and we show a sevenfold increase in EGF expression in FVB compared to B10.Q mice. Tyk2 is a Janus kinase that plays a central role in controlling the T H 1 immune response and we show that attenuation of Tyk2 function correlates with enhanced CNS repair.

ABSTRACTThe RNA-dependent RNA polymerase 3Dpolis 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-Dbmice 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.

ABSTRACT The human monoclonal antibody rHIgM22 enhances remyelination following spinal cord demyelination in a virus‐induced murine model of multiple sclerosis. Using three‐dimensional T2‐weighted in vivo spinal cord magnetic resonance imaging (MRI), we have therefore assessed the extent of spinal cord demyelination, before and after 5 weeks of treatment with rHIgM22, to determine whether antibody enhanced remyelination can be detected by MRI. A significant decrease was seen in T2 high signal lesion volume following antibody treatment. Histologic examination of the spinal cord tissue reveals that this decrease in lesion volume correlates with antibody promoted remyelination. To show that rHIgM22 enters the spinal cord and colocalizes with demyelinating lesions, we used ultrasmall superparamagnetic iron oxide particle (USPIO)‐labeled antibodies. This may be considered as additional evidence to the hypothesis that rHIgM22 promotes remyelination by local effects in the lesions, likely by binding to CNS cells. The reduction in high signal T2‐weighted lesion volume may be an important outcome measure in future clinical trials in humans.

ABSTRACT Certain human sera from patients with monoclonal gammopathies contain factors that induce myelin repair in animals with demyelinating disease. We hypothesize that antibodies functionally distinguish the serum of one patient from another. However, pooled normal polyclonal human IgM antibodies also induce remyelination. Definitive proof that specific antibodies are the biologically active components of serum is missing because unquestionably pure preparations of antibody molecules cannot be generated by fractionation. To demonstrate definitively that antibody is the biologically active component of patient serum, recombinant antibody was generated for evaluation in bioassays. The induction of remyelination in vivo requires milligram quantities of antibody. Consequently, an expression system was engineered to express high‐titer, recombinant human IgM antibodies in vitro. A resulting recombinant antibody (rHIgM22) was evaluated for its ability to induce remyelination in the Theiler's virus mouse model of chronic‐progressive demyelinating disease. We demonstrate that a single recombinant monoclonal antibody recapitulates the key characteristics of patient serum, including binding specificity, the induction of calcium signals in oligodendrocytes in vitro, and the induction of myelin repair within demyelinated plaques in vivo. The rHIgM22 antibody provides a new venue for the analysis of mechanisms governing remyelination and may prove useful in the treatment of demyelinating diseases.