Author Of 1 Presentation
YI01.03 - Inhibition of neuronal RNA binding protein dysfunction as a treatment for neurodegeneration in multiple sclerosis
Abstract
Background
Dysfunctional RNA binding proteins (RBPs), including heterogeneous nuclear ribonucleoprotein A1 (A1), are key pathological features of numerous neurologic diseases. Recently, evidence suggests that dysfunctional RBP biology, including mislocalization of the RBP from its homeostatic nuclear location to the cytoplasm, stress granule (SG) formation, and changes in RNA metabolism, are associated with neurodegeneration and worsened disease in multiple sclerosis (MS) and its models, such as experimental autoimmune encephalomyelitis (EAE).
Objectives
We hypothesized that correcting dysfunctional RBP biology with the nuclear export inhibitor, KPT-276, would restore A1 function by decreasing its nucleocytoplasmic mislocalization and reduce SG formation and neurodegeneration in spinal cord neurons from EAE animals as compared to vehicle controls.
Methods
C57BL/6 female mice were immunized with myelin oligodendrocyte glycoprotein (MOG35-55) to induce EAE. Upon reaching a clinical score of 2.5, mice were treated with KPT-276 (75 mg/kg, oral gavage) or vehicle control every other day for a total of six treatments. Two days following the final treatment, spinal cords were harvested and analyzed using immunofluorescence for A1 localization and SG formation in neurons as well as markers of neurodegeneration.
Results
EAE mice treated with KPT-276 showed a decrease in clinical score severity as compared to vehicle control EAE mice. Furthermore, mice treated with KPT-276 showed a significant reduction in the number of neurons with A1 mislocalization (*p=0.0351), the amount of A1 in the cytoplasm (*p=0.0341), and SG formation (*p=0.0208) as compared to vehicle mice. In the same areas of KPT-276 treated mice where there was a reduction in these features of dysfunctional RBP biology, there was a significant increase in the number of neurons indicative of increased neuronal survival (*p=0.0373).
Conclusions
These experiments suggest that modulating dysfunctional RBP biology through KPT-276 restores RBP function and is a potential therapeutic, which increases neuronal survival and decreases neurodegeneration and clinical disease severity.
Author Of 2 Presentations
P0937 - Altered expression of myelin-related RNA binding proteins in a mouse model of multiple sclerosis (ID 1782)
Abstract
Background
Abnormalities in expression of RNA-binding proteins (RBPs) have been shown to be involved in the pathogenesis of a number of disorders, most notably amyotrophic lateral sclerosis. Recent data demonstrates these RBP abnormalities were also found in the brains of patients with multiple sclerosis (MS) and MS models. Oligodendrocyte-mediated myelination of neuronal axons is essential for axonal integrity and protects neurons from degeneration. Myelin basic protein (MBP) and myelin-associated glycoprotein (MAG) are the two major components of central nervous system (CNS) myelin. The transport and translation of MBP and MAG mRNAs in oligodendrocytes are regulated by diverse RBPs. Our lab previously demonstrated that dysfunction of RBPs including heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) in neurons is a key contributor to neurodegenerative-mediated mechanisms in MS and its models. Therefore, neurodegeneration is a component of MS pathology, however, the underlying mechanisms behind this remain unknown.
Objectives
We tested the hypothesis that myelin-related RBPs are differentially expressed in the CNS of mice with experimental autoimmune encephalomyelitis (EAE).
Methods
EAE was induced in female C57BL/6 mice by immunization with myelin oligodendrocyte glycoprotein (MOG35-55). Animals (n=4 each EAE and naïve control) were observed clinically and spinal cord tissues were harvested at the peak of EAE for detection of the myelin related RBPs hnRNP A1, A2, K, E, and F using western blot.
Results
Quantitative analyses showed a significant increase in hnRNP A1 protein expression (p=0.007, unpaired tailed t-test) in spinal cords of mice with EAE. In contrast, hnRNP A2 (p=0.03) and hnRNP K (p=0.002) showed reduced expression. There were no significant differences in the expression levels of hnRNP E and F comparing EAE with naïve animals.
Conclusions
These data indicate that altered expression of the myelin-related RBPs hnRNP A1, hnRNP A2, and hnRNP K may contribute to demyelination and neurodegeneration in EAE, which might also apply to the pathogenesis of MS.
P0959 - Dysfunction of the RNA binding protein hnRNP A1 contributes to disease progression and neurodegeneration in an animal model of multiple sclerosis (ID 1437)
Abstract
Background
Loss of neurons and axons, collectively known as neurodegeneration, is characteristic of multiple sclerosis (MS), correlating with permanent disability. Dysfunctional RNA binding proteins (RBPs) underlie neurodegeneration in neurological diseases. Features of RBP dysfunction include mislocalization from its homeostatic nuclear location to the cytoplasm and formation of cytoplasmic stress granules (SGs). Neurons in MS brains display characteristic features of heterogenous nuclear ribonucleoprotein A1 (A1) dysfunction including its cytoplasmic mislocalization and depletion from the nucleus. Further, MS patients make antibodies to A1, and injections of anti-A1 antibodies into mice with experimental autoimmune encephalomyelitis (EAE – an animal model of MS) resulted in increased neurodegeneration.
Objectives
To determine how A1 dysfunction and anti-A1 antibodies contribute mechanistically to disease progression and NDG in an animal model of MS.
Methods
EAE was induced by immunization with myelin oligodendrocyte glycoprotein35-55. At symptom onset, mice were injected with anti-A1 antibodies or saline (control). Mice were sacrificed at five timepoints over a 21-day time course. Tissue was analyzed quantitatively for A1 mislocalization, SGs and neuronal loss (a marker of neurodegeneration) by immunohistochemistry.
Results
Mice in the EAE control group displayed neuronal A1 mislocalization (p<0.0001) and SG formation (p<0.01), which peaked at symptom onset concurrent with neuronal loss (p<0.01). After symptom onset, A1 mislocalization, SG formation returned to pre-symptomatic levels. Injections of anti-A1 antibodies into mice with EAE resulted in greater disability (p<0.05) and exacerbation of neuronal A1 mislocalization (p<0.05) and SG formation (p<0.05), including nuclear depletion of A1 (p<0.0001), a pathogenic neuronal phenotype in MS brains. These findings preceded neuronal cell loss. The anti-A1 antibodies also exacerbated neuronal cell loss (p<0.05), which did not recover and continued until the 21-day time point.
Conclusions
In contrast to controls, EAE mice injected with anti-A1 antibodies showed that RBP dysfunction occurred prior to neuronal cell body death (a marker of neurodegeneration) indicative of A1 dysfunction triggering, rather than resulting from neurodegeneration. The antibodies also exacerbated and caused permanent neuronal damage. These data reveal a novel mechanism of neurodegeneration, which can be targeted to inhibit disability in MS.
Presenter Of 1 Presentation
P0959 - Dysfunction of the RNA binding protein hnRNP A1 contributes to disease progression and neurodegeneration in an animal model of multiple sclerosis (ID 1437)
Abstract
Background
Loss of neurons and axons, collectively known as neurodegeneration, is characteristic of multiple sclerosis (MS), correlating with permanent disability. Dysfunctional RNA binding proteins (RBPs) underlie neurodegeneration in neurological diseases. Features of RBP dysfunction include mislocalization from its homeostatic nuclear location to the cytoplasm and formation of cytoplasmic stress granules (SGs). Neurons in MS brains display characteristic features of heterogenous nuclear ribonucleoprotein A1 (A1) dysfunction including its cytoplasmic mislocalization and depletion from the nucleus. Further, MS patients make antibodies to A1, and injections of anti-A1 antibodies into mice with experimental autoimmune encephalomyelitis (EAE – an animal model of MS) resulted in increased neurodegeneration.
Objectives
To determine how A1 dysfunction and anti-A1 antibodies contribute mechanistically to disease progression and NDG in an animal model of MS.
Methods
EAE was induced by immunization with myelin oligodendrocyte glycoprotein35-55. At symptom onset, mice were injected with anti-A1 antibodies or saline (control). Mice were sacrificed at five timepoints over a 21-day time course. Tissue was analyzed quantitatively for A1 mislocalization, SGs and neuronal loss (a marker of neurodegeneration) by immunohistochemistry.
Results
Mice in the EAE control group displayed neuronal A1 mislocalization (p<0.0001) and SG formation (p<0.01), which peaked at symptom onset concurrent with neuronal loss (p<0.01). After symptom onset, A1 mislocalization, SG formation returned to pre-symptomatic levels. Injections of anti-A1 antibodies into mice with EAE resulted in greater disability (p<0.05) and exacerbation of neuronal A1 mislocalization (p<0.05) and SG formation (p<0.05), including nuclear depletion of A1 (p<0.0001), a pathogenic neuronal phenotype in MS brains. These findings preceded neuronal cell loss. The anti-A1 antibodies also exacerbated neuronal cell loss (p<0.05), which did not recover and continued until the 21-day time point.
Conclusions
In contrast to controls, EAE mice injected with anti-A1 antibodies showed that RBP dysfunction occurred prior to neuronal cell body death (a marker of neurodegeneration) indicative of A1 dysfunction triggering, rather than resulting from neurodegeneration. The antibodies also exacerbated and caused permanent neuronal damage. These data reveal a novel mechanism of neurodegeneration, which can be targeted to inhibit disability in MS.