Regional CNS responses to IFN-γ determine lesion localization patterns during EAE pathogenesis

The localization of inflammatory foci within the cerebellum is correlated to severe clinical outcomes in multiple sclerosis (MS). Previous studies of experimental autoimmune encephalomyelitis (EAE), a model of MS, revealed distinct clinical outcomes correlated with the capacity of the animal to produce IFN-γ. Outcomes were linked to localization of inflammatory cells in either the spinal cord (wild type [WT]) or the cerebellum and brain stem (IFN-γ deficient). We demonstrate, using an adoptive transfer system, that the ability of the central nervous system (CNS) to sense pathogenic T cell–produced IFN-γ during EAE initiation determines the sites of CNS pathogenesis. Transfer of WT Th1 cells into IFN-γ receptor–deficient mice results in pathogenic invasion of the brain stem and cerebellum with attendant clinical symptoms, which are identical to the disease observed after transfer of IFN-γ–deficient T cells to WT hosts. Inflammation of the spinal cord associated with classical EAE is abrogated in both IFN-γ–deficient systems. Cotransfer of CNS antigen-specific WT Th1 cells with IFN-γ–deficient T cells is sufficient to restore spinal cord invasion and block cerebellar and brain stem invasion. These data demonstrate that interaction between IFN-γ and host CNS cells during the initiation of EAE can selectively promote or suppress neuroinflammation and pathogenesis

One Year Outcome of Boys With Duchenne Muscular Dystrophy Using the Bayley-III Scales of Infant and Toddler Development

BACKGROUND: The pathogenesis of Duchenne muscular dystrophy starts prior to birth. Despite this, clinical trials exclude young boys because traditional outcome measures rely on cooperation. We recently used the Bayley-III Scales of Infant and Toddler Development to study 24 infants and boys with Duchenne muscular dystrophy. Clinical evaluators at six centers were trained and certified to perform the Bayley-III. Here we report six and twelve month follow-up of two subsets of these boys. PATIENTS: Nineteen boys (1.9 ± 0.8 years) were assessed at baseline and six months. Twelve boys (1.5 ± 0.8 years) were assessed at baseline, six, and twelve months. RESULTS: Gross motor scores were lower at baseline compared to published controls (6.2 ± 1.7; normal 10 ± 3; p<.0001), and showed a further declining trend to 5.7 ± 1.7 (p =.20) at six months. Repeated measures analysis of the 12 boys followed for 12 months showed that gross motor scores, again low at baseline (6.6 ± 1.7; p<.0001), declined at six months (5.9 ± 1.8) and further at 12 months (5.3 ± 2.0) (p=0.11). Cognitive and language scores were lower at baseline compared to normal children (range p=.002 to p<0.0001) and did not change significantly at 6 or 12 months (range p=.89 to p=.09). Fine motor skills, also low at baseline, improved over one year (p=.05). CONCLUSION: Development can reliably be measured in infants and young boys with DMD across time using the Bayley-III. Power calculations using these data show that motor development may be used as an outcome measure

PTP1B is a negative regulator of interleukin 4–induced STAT6 signaling

Protein tyrosine phosphatase 1B (PTP1B) is a ubiquitously expressed enzyme shown to negatively regulate multiple tyrosine phosphorylation-dependent signaling pathways. PTP1B can modulate cytokine signaling pathways by dephosphorylating JAK2, TYK2, and STAT5a/b. Herein, we report that phosphorylated STAT6 may serve as a cytoplasmic substrate for PTP1B. Overexpression of PTP1B led to STAT6 dephosphorylation and the suppression of STAT6 transcriptional activity, whereas PTP1B knockdown or deficiency augmented IL-4–induced STAT6 signaling. Pretreatment of these cells with the PTK inhibitor staurosporine led to sustained STAT6 phosphorylation consistent with STAT6 serving as a direct substrate of PTP1B. Furthermore, PTP1B-D181A “substrate-trapping” mutants formed stable complexes with phosphorylated STAT6 in a cellular context and endogenous PTP1B and STAT6 interacted in an interleukin 4 (IL-4)–inducible manner. We delineate a new negative regulatory loop of IL-4–JAK-STAT6 signaling. We demonstrate that IL-4 induces PTP1B mRNA expression in a phosphatidylinositol 3-kinase–dependent manner and enhances PTP1B protein stability to suppress IL-4–induced STAT6 signaling. Finally, we show that PTP1B expression may be preferentially elevated in activated B cell–like diffuse large B-cell lymphomas. These observations identify a novel regulatory loop for the regulation of IL-4–induced STAT6 signaling that may have important implications in both neoplastic and inflammatory processes