Targetability of the neurovascular unit in inflammatory diseases of the central nervous system.

The blood-brain barrier (BBB) is a selectively permeable barrier separating the periphery from the central nervous system (CNS). The BBB restricts the flow of most material into and out of the CNS, including many drugs that could be used as potent therapies. BBB permeability is modulated by several cells that are collectively called the neurovascular unit (NVU). The NVU consists of specialized CNS endothelial cells (ECs), pericytes, astrocytes, microglia, and neurons. CNS ECs maintain a complex "seal" via tight junctions, forming the BBB; breakdown of these tight junctions leads to BBB disruption. Pericytes control the vascular flow within capillaries and help maintain the basal lamina. Astrocytes control much of the flow of material that has moved beyond the CNS EC layer and can form a secondary barrier under inflammatory conditions. Microglia survey the border of the NVU for noxious material. Neuronal activity also plays a role in the maintenance of the BBB. Since astrocytes, pericytes, microglia, and neurons are all able to modulate the permeability of the BBB, understating the complex contributions of each member of the NVU will potentially uncover novel and effective methods for delivery of neurotherapies to the CNS.

Targeting IFN-λ Signaling Promotes Recovery from Central Nervous System Autoimmunity.

Type III IFNs (IFNLs) are newly discovered cytokines, acting at epithelial and other barriers, that exert immunomodulatory functions in addition to their primary roles in antiviral defense. In this study, we define a role for IFNLs in maintaining autoreactive T cell effector function and limiting recovery in a murine model of multiple sclerosis (MS), experimental autoimmune encephalomyelitis. Genetic or Ab-based neutralization of the IFNL receptor (IFNLR) resulted in lack of disease maintenance during experimental autoimmune encephalomyelitis, with loss of CNS Th1 effector responses and limited axonal injury. Phenotypic effects of IFNLR signaling were traced to increased APC function, with associated increase in T cell production of IFN-γ and GM-CSF. Consistent with this, IFNL levels within lesions of CNS tissues derived from patients with MS were elevated compared with MS normal-appearing white matter. Furthermore, expression of IFNLR was selectively elevated in MS active lesions compared with inactive lesions or normal-appearing white matter. These findings suggest IFNL signaling as a potential therapeutic target to prevent chronic autoimmune neuroinflammation.

Feeding Management and Palate Repair Timing in Infants with Cleft Palate with and without Pierre Robin Sequence: A Multisite Study.

OBJECTIVES: Compare the feeding management practices in infants with cleft palate with and without Pierre Robin sequence (PRS) and determine if specific feeding difficulties or interventions predict delayed palate repair. DESIGN: Retrospective cross-sectional study. SETTING: Seventeen cleft palate teams contributed data. PATIENTS: 414 infants were included in this study: 268 infants with cleft palate only and 146 infants with cleft palate and PRS. PROCEDURES: Data were collected via parent interview and electronic health records. MAIN OUTCOME MEASURES: Outcomes for the primary objective included categorical data for: history of poor growth, feeding therapy, milk fortification, use of enteral feeding, and feeding difficulties. The outcome for the secondary objective was age in months at primary palate repair. RESULTS: Infants with PRS had a significantly higher prevalence of feeding difficulties (81% versus 61%) and poor growth (29% versus 15%) compared to infants with cleft palate only. Infants with PRS received all feeding interventions-including feeding therapy, milk fortification, and enteral feeding-at a significantly higher frequency. Infants with PRS underwent primary palate repair at a mean age of 13.55 months (SD = 3.29) which was significantly (P < .00001) later than infants with cleft palate only who underwent palate repair at a mean age of 12.05 months (SD = 2.36). Predictors of delayed palate repair included diagnosis of PRS as well as Hispanic ethnicity and a history of poor growth. CONCLUSIONS: These findings can be used to establish clinical directives focused on providing early, multimodal feeding interventions to promote optimal growth and timely palate repair for infants with PRS.

Can MRI Replace Nasopharyngoscopy in the Evaluation of Velopharyngeal Insufficiency?

OBJECTIVE: To investigate whether flexible nasopharyngoscopy, when performed in addition to magnetic resonance imaging (MRI), influences the type of surgery selected or success of surgery in patients with velopharyngeal insufficiency (VPI). DESIGN: Cohort study. SETTING: A metropolitan children's hospital. PATIENTS: Patients with non-syndromic, repaired cleft palate presenting for management of VPI. INTERVENTIONS: MRI and nasopharyngoscopy or MRI alone for preoperative imaging of the velopharyngeal mechanism. MAIN OUTCOME MEASURES: (1) Surgical selection and (2) resolution of hypernasality. All speech, MRI, and nasopharyngoscopy measurements were performed by raters blinded to patients' medical and surgical history. RESULTS: Of the 25 patients referred for nasopharyngoscopy, 76% completed the exam. Of the 41 patients referred for MRI, the scan was successfully completed by 98% of patients. Completion of nasopharyngoscopy was significantly (p=0.01) lower than MRI. Surgical selection did not significantly differ (p=0.73) between the group receiving MRI and nasopharyngoscopy and the group receiving MRI alone, nor was there a significant difference between these groups in the proportion of patients achieving resolution of hypernasality postoperatively (p=0.63). Percent total velopharyngeal closure assessments on nasopharyngoscopy and MRI were strongly correlated (r=0.73). CONCLUSIONS: In patients receiving MRI as part of their preoperative VPI evaluation, the addition of nasopharyngoscopy did not result in a difference in surgical selection or resolution of hypernasality. Routine inclusion of nasopharyngoscopy may not be necessary for the evaluation of velopharyngeal anatomy when MRI is available.

Immunity impacts cognitive deficits across neurological disorders.

Cognitive deficits are a common comorbidity with neurological disorders and normal aging. Inflammation is associated with multiple diseases including classical neurodegenerative dementias such as Alzheimer's disease (AD) and autoimmune disorders such as multiple sclerosis (MS), in which over half of all patients experience some form of cognitive deficits. Other degenerative diseases of the central nervous system (CNS) including frontotemporal lobe dementia (FTLD), and Parkinson's disease (PD) as well as traumatic brain injury (TBI) and psychological disorders like major depressive disorder (MDD), and even normal aging all have cytokine-associated reductions in cognitive function. Thus, there is likely commonality between these secondary cognitive deficits and inflammation. Neurological disorders are increasingly associated with substantial neuroinflammation, in which CNS-resident cells secrete cytokines and chemokines such as tumor necrosis factor (TNF)α and interleukins (ILs) including IL-1ß and IL-6. CNS-resident cells also respond to a wide variety of cytokines and chemokines, which can have both direct effects on neurons by changing the expression of ion channels and perturbing electrical properties, as well as indirect effects through glia-glia and immune-glia cross-talk. There is significant overlap in these cytokine and chemokine expression profiles across diseases, with TNFα and IL-6 strongly associated with cognitive deficits in multiple disorders. Here, we review the involvement of various cytokines and chemokines in AD, MS, FTLD, PD, TBI, MDD, and normal aging in the absence of dementia. We propose that the neuropsychiatric phenotypes observed in these disorders may be at least partially attributable to a dysregulation of immunity resulting in pathological cytokine and chemokine expression from both CNS-resident and non-resident cells.

Astrocyte interferon-gamma signaling dampens inflammation during chronic central nervous system autoimmunity via PD-L1.

Multiple sclerosis (MS) is an inflammatory and neurodegenerative disease of the central nervous system (CNS). Infiltrating inflammatory immune cells perpetuate demyelination and axonal damage in the CNS and significantly contribute to pathology and clinical deficits. While the cytokine interferon (IFN)γ is classically described as deleterious in acute CNS autoimmunity, we and others have shown astrocytic IFNγ signaling also has a neuroprotective role. Here, we performed RNA sequencing and ingenuity pathway analysis on IFNγ-treated astrocytes and found that PD-L1 was prominently expressed. Interestingly, PD-1/PD-L1 antagonism reduced apoptosis in leukocytes exposed to IFNγ-treated astrocytes in vitro. To further elucidate the role of astrocytic IFNγ signaling on the PD-1/PD-L1 axis in vivo, we induced the experimental autoimmune encephalomyelitis (EAE) model of MS in Aldh1l1-CreERT2, Ifngr1fl/fl mice. Mice with conditional astrocytic deletion of IFNγ receptor exhibited a reduction in PD-L1 expression which corresponded to increased infiltrating leukocytes, particularly from the myeloid lineage, and exacerbated clinical disease. PD-1 agonism reduced EAE severity and CNS-infiltrating leukocytes. Importantly, PD-1 is expressed by myeloid cells surrounding MS lesions. These data support that IFNγ signaling in astrocytes diminishes inflammation during chronic autoimmunity via upregulation of PD-L1, suggesting potential therapeutic benefit for MS patients.

Octopamine neuron dependent aggression requires dVGLUT from dual-transmitting neurons.

Neuromodulators such as monoamines are often expressed in neurons that also release at least one fast-acting neurotransmitter. The release of a combination of transmitters provides both "classical" and "modulatory" signals that could produce diverse and/or complementary effects in associated circuits. Here, we establish that the majority of Drosophila octopamine (OA) neurons are also glutamatergic and identify the individual contributions of each neurotransmitter on sex-specific behaviors. Males without OA display low levels of aggression and high levels of inter-male courtship. Males deficient for dVGLUT solely in OA-glutamate neurons (OGNs) also exhibit a reduction in aggression, but without a concurrent increase in inter-male courtship. Within OGNs, a portion of VMAT and dVGLUT puncta differ in localization suggesting spatial differences in OA signaling. Our findings establish a previously undetermined role for dVGLUT in OA neurons and suggests that glutamate uncouples aggression from OA-dependent courtship-related behavior. These results indicate that dual neurotransmission can increase the efficacy of individual neurotransmitters while maintaining unique functions within a multi-functional social behavior neuronal network.

Current Postoperative Feeding Practices Following Surgical Repairs for Infants With Cleft Palate.

BACKGROUND: Nearly all surgeons have restrictive postoperative feeding protocols in place after primary cleft lip and cleft palate repairs. There are no standardized recommendations, potentially resulting in widely variable practices among cleft surgeons and teams. The purpose of this study was to examine current postoperative feeding practices for infants with cleft palate after lip and palate repairs. METHODS: A survey of 50 questions was sent to members of the American Cleft Palate-Craniofacial Association (ACPA). Inclusion criteria included providers from North America that have either currently or previously served on a cleft palate team and reached the surgical question set within the survey. RESULTS: Sixty-four respondents met inclusion criteria. The majority were in speech-language pathology (47%) or nursing (41%) disciplines, involved in feeding consultations frequently (84%), and working in an outpatient setting (69%). After lip surgery, respondents recommended cleft-adapted bottle feeding (88%), spoon feeding (9%), cup feeding (13%), and syringe/squeeze bottle feeding (23%). The majority of respondents (69%) indicated infants could return to their preoperative feeding modality immediately after lip surgery. After palate surgery, respondents recommended cleft-adapted bottle feeding (55%), typical bottle feeding (3%), spoon feeding (36%), cup feeding (64%), and syringe/squeeze bottle feeding (30%). Infants could use a feeding system that required suction at an average of 20 days postoperatively and return to an age-appropriate diet at an average of 15 days postoperatively. CONCLUSIONS: The present study describes the wide variation of postoperative feeding guidelines used by cleft teams after lip and palate repairs.

Nonsedated Magnetic Resonance Imaging for Visualization of the Velopharynx in the Pediatric Population.

BACKGROUND: Non-sedated MRI is gaining traction in clinical settings for visualization of the velopharynx in children with velopharyngeal insufficiency. However, the behavioral adaptation and training aspects that are essential for successful pediatric MRI have received limited attention. SOLUTION: We outline a program of behavioral modifications combined with patient education and provider training that has led to high success rates for non-sedated velopharyngeal MRI in children.

VPI Management in SATB2 Syndrome: Use of MRI to Evaluate Anatomy and Physiology in Non-Cleft VPI.

This clinical case study describes the velopharyngeal anatomy and physiology in a patient who presented with SATB2-associated syndrome (SAS) and velopharyngeal insufficiency (VPI) in the absence of an overt cleft palate. The clinical presentation, treatment, outcome, and the contribution of anatomical findings from MRI to surgical treatment planning for this rare genetic disorder, SAS, are described. This case study contributes to our current understanding of the anatomy and physiology of the velopharyngeal mechanism in an individual born with SAS and non-cleft VPI. It also details the changes following bilateral buccal myomucosal flaps in this patient.

Assessing the Agreement of Hypernasality and Audible Nasal Emission Ratings Between Audio-Recordings and a Clinic Setting.

Assess agreement of hypernasality and audible nasal emission (ANE) ratings between audio-recordings and a clinic setting.Cross-sectional study using retrospective clinical recordings.Audio-recording ratings by two trained speech language pathologists.Percent agreement and intra- and inter-rater reliability of perceptual ratings.Intra-rater reliability (AC2) of 167 audio-recorded speech samples for the primary and secondary raters, respectively, was 0.82 and 0.79 for hypernasality; for ANE, it was 0.57 and 0.75. Inter-rater reliability was 0.77 for hypernasality and 0.63 for ANE. When comparing ratings made from audio-recording versus the original clinical ratings, intra-rater reliability was 0.85 and 0.61 (primary and secondary rater, respectively) for hypernasality and 0.21 and 0.34 for ANE.Ratings for hypernasality made from audio recordings were consistent with clinical evaluation, while ratings of ANE were not. ANE ratings made from audio recordings may not be a valid measure of velopharyngeal insufficiency speech characteristics.

Does Notching Along the Nasal Velar Surface During Nasopharyngoscopy Predict Discontinuity of the Underlying Levator Veli Palatini Muscle?

To determine the sensitivity and specificity of velar notching seen on nasopharyngoscopy for levator veli palatini (LVP) muscle discontinuity and anterior positioning.Nasopharyngoscopy and MRI of the velopharynx were performed on patients with VPI as part of their routine clinical care. Two speech-language pathologists independently evaluated nasopharyngoscopy studies for the presence or absence of velar notching. MRI was used to evaluate LVP muscle cohesiveness and position relative to the posterior hard palate. To determine the accuracy of velar notching for detecting LVP muscle discontinuity, sensitivity, specificity, and positive predictive value (PPV) were calculated.A craniofacial clinic at a large metropolitan hospital. PARTICIPANTS: Thirty-seven patients who presented with hypernasality and/or audible nasal emission on speech evaluation and completed nasopharyngoscopy and velopharyngeal MRI study as part of their preoperative clinical evaluation.Among patients with partial or total LVP dehiscence on MRI, presence of a notch accurately identified discontinuity in the LVP 43% (95% CI 22-66%) of the time. In contrast, the absence of a notch accurately indicated LVP continuity 81% (95% CI 54-96%) of the time. The PPV for the presence of notching to identify a discontinuous LVP was 78% (95% CI 49-91%). The distance from the posterior edge of the hard palate to the LVP, known as effective velar length, was similar in patients with and without notching (median 9.8 mm vs 10.5 mm, P = 1.00).The observation of a velar notch on nasopharyngoscopy is not an accurate predictor of LVP muscle dehiscence or anterior positioning.

Astrocyte-T cell crosstalk regulates region-specific neuroinflammation.

During multiple sclerosis (MS), an inflammatory and neurodegenerative disease of the central nervous system (CNS), symptoms, and outcomes are determined by the location of inflammatory lesions. While we and others have shown that T cell cytokines differentially regulate leukocyte entry into perivascular spaces and regional parenchymal localization in murine models of MS, the molecular mechanisms of this latter process are poorly understood. Here, we demonstrate that astrocytes exhibit region-specific responses to T cell cytokines that promote hindbrain versus spinal cord neuroinflammation. Analysis of cytokine receptor expression in human astrocytes showed region-specific responsiveness to Th1 and Th17 inflammatory cytokines. Consistent with this, human and murine astrocytes treated with these cytokines exhibit differential expression of the T cell localizing molecules VCAM-1 and CXCR7 that is both cytokine and CNS region-specific. Using in vivo models of spinal cord versus brain stem trafficking of myelin-specific T cells and astrocyte-specific deletion strategies, we confirmed that Th1 and Th17 cytokines differentially regulate astrocyte expression of VCAM-1 and CXCR7 in these locations. Finally, stereotaxic injection of individual cytokines into the hindbrain or spinal cord revealed region- and cytokine-specific modulation of localizing cue expression by astrocytes. These findings identify a role for inflammatory cytokines in mediating local astrocyte-dependent mechanisms of immune cell trafficking within the CNS during neuroinflammation.

The impact of regional astrocyte interferon-γ signaling during chronic autoimmunity: a novel role for the immunoproteasome.

BACKGROUND: In early autoimmune neuroinflammation, interferon (IFN)γ and its upregulation of the immunoproteasome (iP) is pathologic. However, during chronic multiple sclerosis (MS), IFNγ has protective properties. Although dysregulation of the iP has been implicated in neurodegeneration, its function remains to be fully elucidated. Here, we demonstrate that IFNγ signaling in regional astrocytes induces the iP and promotes protection of the CNS during chronic autoimmunity. METHODS: In a multiple sclerosis (MS) brain, we evaluated mRNA expression and labeled postmortem MS brainstem and spinal cord for iP subunits and indicators of oxidative stress. Primary regional human astrocytes were analyzed for iP regulation and function by quantitative reverse transcription-polymerase chain reaction (qRT-PCR), Western blot, OxyBlot, and reactive oxygen species and caspase activity detection assays. Following immunization with myelin oligodendrocyte glycoprotein (MOG)35-55, the role of IFNγ signaling and the iP during chronic experimental autoimmune encephalomyelitis (EAE) were assessed using pharmacologic inhibition of the iP and genetic interruption of IFNγ signaling specifically in astrocytes. Central nervous system (CNS) tissues were analyzed by immunohistochemistry (IHC) and immunofluorescence, and cell-specific colocalization was quantified. RESULTS: In MS tissue, iP expression was enhanced in the spinal cord compared to brainstem lesions, which correlated with a decrease in oxidative stress. In vitro, IFNγ stimulation enhanced iP expression, reduced reactive oxygen species burden, and decreased oxidatively damaged and poly-ubiquitinated protein accumulation preferentially in human spinal cord astrocytes, which was abrogated with the use of the iP inhibitor, ONX 0914. During the chronic phase of an MS animal model, EAE, ONX 0914 treatment exacerbated the disease and led to increased oxidative stress and poly-ubiquitinated protein buildup. Finally, mice with astrocyte-specific loss of the IFNγ receptor exhibited worsened chronic EAE associated with reduced iP expression, enhanced lesion size and oxidative stress, and poly-ubiquitinated protein accumulation in astrocytes. CONCLUSIONS: Taken together, our data reveal a protective role for IFNγ in chronic neuroinflammation and identify a novel function of the iP in astrocytes during CNS autoimmunity.

The Effectiveness of Palate Re-Repair for Treating Velopharyngeal Insufficiency: A Systematic Review and Meta-Analysis.

BACKGROUND: Palate re-repair has been proposed as an effective treatment for velopharyngeal insufficiency (VPI) with a low risk of obstructive sleep apnea (OSA). The authors conducted a systematic review and meta-analysis to determine the proportion of patients achieving normal speech resonance following palate re-repair for VPI, the proportion developing OSA, and the criteria for patient selection that are associated with increased effectiveness. METHODS: PubMed, Embase, and Scopus were searched from inception through April 2018 for English language articles evaluating palate re-repair for the treatment of VPI in patients with a repaired cleft palate. Inclusion criteria included reporting of hypernasality, nasal air emission, nasometry, additional VPI surgery, and/or OSA outcomes. Meta-analysis was conducted using random effects models. Risk of bias was assessed regarding criteria for patient selection, blinding of outcome assessors, and validity of speech assessment scale. RESULTS: Eighteen studies met inclusion criteria. The incidence of achieving no consistent hypernasality follow palate re-repair was 61% (95% confidence interval [CI]: 44%-75%). The incidence of additional surgery for persistent VPI symptoms was 21% (95% CI: 12%-33%). The incidence of OSA was 28% (95% CI: 13%-49%). Criteria for selecting patients to undergo re-repair varied, with anterior/sagittal position of palatal muscles (33%) and small velopharyngeal gap (22%) being the most common. No specific patient selection criteria led to superior speech outcomes (P = .6572). CONCLUSIONS: Palate re-repair achieves normal speech resonance in many but not all patients with VPI. Further research is needed to identify the specific examination and imaging findings that predict successful correction of VPI with re-repair.

Macrophage migration inhibitory factor potentiates autoimmune-mediated neuroinflammation.

Macrophage migration inhibitory factor (MIF) is a multipotent cytokine that is associated with clinical worsening and relapses in multiple sclerosis (MS) patients. The mechanism through which MIF promotes MS progression remains undefined. In this study, we identify a critical role for MIF in regulating CNS effector mechanisms necessary for the development of inflammatory pathology in a mouse model of MS, experimental autoimmune encephalomyelitis (EAE). Despite the ability to generate pathogenic myelin-specific immune responses peripherally, MIF-deficient mice have reduced EAE severity and exhibit less CNS inflammatory pathology, with a greater percentage of resting microglia and fewer infiltrating inflammatory macrophages. We demonstrate that MIF is essential for promoting microglial activation and production of the innate soluble mediators IL-1ß, IL-6, TNF-α, and inducible NO synthase. We propose a novel role for MIF in inducing microglial C/EBP-ß, a transcription factor shown to regulate myeloid cell function and play an important role in neuroinflammation. Intraspinal stereotaxic microinjection of MIF resulted in upregulation of inflammatory mediators in microglia, which was sufficient to restore EAE-mediated inflammatory pathology in MIF-deficient mice. To further implicate a role for MIF, we show that MIF is highly expressed in human active MS lesions. Thus, these results illustrate the ability of MIF to influence the CNS cellular and molecular inflammatory milieu during EAE and point to the therapeutic potential of targeting MIF in MS.

miR-29ab1 deficiency identifies a negative feedback loop controlling Th1 bias that is dysregulated in multiple sclerosis.

Th cell programming and function is tightly regulated by complex biological networks to prevent excessive inflammatory responses and autoimmune disease. The importance of microRNAs (miRNAs) in this process is highlighted by the preferential Th1 polarization of Dicer-deficient T cells that lack miRNAs. Using genetic knockouts, we demonstrate that loss of endogenous miR-29, derived from the miR-29ab1 genomic cluster, results in unrestrained T-bet expression and IFN-γ production. miR-29b regulates T-bet and IFN-γ via a direct interaction with the 3' untranslated regions, and IFN-γ itself enhances miR-29b expression, establishing a novel regulatory feedback loop. miR-29b is increased in memory CD4(+) T cells from multiple sclerosis (MS) patients, which may reflect chronic Th1 inflammation. However, miR-29b levels decrease significantly upon T cell activation in MS patients, suggesting that this feedback loop is dysregulated in MS patients and may contribute to chronic inflammation. miR-29 thus serves as a novel regulator of Th1 differentiation, adding to the understanding of T cell-intrinsic regulatory mechanisms that maintain a balance between protective immunity and autoimmunity.

A novel PSMB8 isoform associated with multiple sclerosis lesions induces P-body formation.

Multiple sclerosis (MS) is an inflammatory and demyelinating disease of the central nervous system (CNS). Current therapies primarily target the inflammatory component of the disease and are highly effective in early stages of MS while limited therapies have an effect in the more chronic progressive stages of MS where resident glia have a larger role. MS lesions tend to be inflammatory even after the initial peripheral immune cell invasion has subsided and this inflammation is known to cause alternative splicing events. We used qPCR of normal-appearing white matter and white matter lesions from postmortem MS tissue, in vitro studies, and immunostaining in MS tissue to investigate the alternative splicing of one gene known to be important during recovery in an animal model of MS, PSMB8. We found a novel, intron-retained isoform which has not been annotated, upregulated specifically in MS patient white matter lesions. We found that this novel isoform activates the nonsense-mediated decay pathway in primary human astrocytes, the most populous glial cell in the CNS, and is then degraded. Overexpression of this isoform in astrocytes leads to an increased number of processing bodies in vitro, the primary site of mRNA decay. Finally, we demonstrated that MS white matter lesions have a higher burden of processing bodies compared to normal-appearing white matter, predominantly in GFAP-positive astrocytes. The increase in alternative splicing of the PSMB8 gene, the stress that this alternative splicing causes, and the observation that processing bodies are increased in white matter lesions suggests that the lesion microenvironment may lead to increased alternative splicing of many genes. This alternative splicing may blunt the protective or reparative responses of resident glia in and around white matter lesions in MS patients.

A novel PSMB8 isoform associated with multiple sclerosis lesions induces P-body formation.

Introduction: Multiple sclerosis (MS) is an inflammatory and demyelinating disease of the central nervous system (CNS). Current therapies primarily target the inflammatory component of the disease and are highly effective in early stages of MS while limited therapies have an effect in the more chronic progressive stages of MS where resident glia have a larger role. MS lesions tend to be inflammatory even after the initial peripheral immune cell invasion has subsided and this inflammation is known to cause alternative splicing events. Methods: We used qPCR of normal-appearing white matter and white matter lesions from postmortem MS tissue, in vitro studies, and immunostaining in MS tissue to investigate the alternative splicing of one gene known to be important during recovery in an animal model of MS, PSMB8. Results: We found a novel, intron-retained isoform which has not been annotated, upregulated specifically in MS patient white matter lesions. We found that this novel isoform activates the nonsense-mediated decay pathway in primary human astrocytes, the most populous glial cell in the CNS, and is then degraded. Overexpression of this isoform in astrocytes leads to an increased number of processing bodies in vitro, the primary site of mRNA decay. Finally, we demonstrated that MS white matter lesions have a higher burden of processing bodies compared to normal-appearing white matter, predominantly in GFAP-positive astrocytes. Discussion: The increase in alternative splicing of the PSMB8 gene, the stress that this alternative splicing causes, and the observation that processing bodies are increased in white matter lesions suggests that the lesion microenvironment may lead to increased alternative splicing of many genes. This alternative splicing may blunt the protective or reparative responses of resident glia in and around white matter lesions in MS patients.