IFN-β, a type I interferon, has been used as a first-line therapy for patients with multiple sclerosis (MS) for more than 30 years; however, the cellular and molecular basis of its therapeutic efficacy remains unclear. Here, we first used experimental autoimmune encephalomyelitis (EAE), a mouse model for MS, to show that the therapeutic effects of IFN-β were associated with a down-regulation of microRNA-21 (miR-21) and pathogenic TH17 (pTH17) cells. In vitro experiments demonstrated that genetic knockout of miR-21 directly inhibited pathogenic TH17 cell differentiation. Further mechanistic investigations revealed that miR-21 promoted pathogenic TH17 differentiation by inhibiting the transcription factor Forkhead box protein O1 (Foxo1). Accordingly, miR-21 loss abrogated pathogenic TH17 differentiation and conferred resistance to EAE. Treatment of T cell monocultures with IFN-β showed that IFN-β did not directly limit miR-21 expression. Instead, IFN-β treatment inhibited the secretion of miR-21-inducing cytokines from myeloid cells, reduced miR-21 induction within cocultured T cells, and inhibited pathogenic TH17 development. In patient samples, immunophenotypic and targeted transcriptomic analyses revealed that compared with IFN-β treatment responders, nonresponders expressed elevated miR-21-inducing cytokines within myeloid cells, alongside increased miR-21 and pathogenic TH17 cytokines within CD4+ T cells. Direct miR-21 inhibition reduced pathogenic TH17 differentiation in nonresponder CD4+ T cells. These results suggest that type I IFN signaling limits central nervous system autoimmunity by inhibiting miR-21-mediated pathogenic TH17 development. miR-21 inhibition may be of potential therapeutic value specifically for the IFN-β nonresponder cohort.

BackgroundPreclinical risk for Alzheimer's disease (AD), including amyloid-β (Aβ) deposition, begins 10-15 years prior to diagnosis. In addition to genetics, hypertension, type 2 diabetes, and depression in midlife are major risk factors for AD.ObjectiveHere, we assessed sex differences in associations of AD risk status with memory circuitry function and AD pathology in midlife.MethodsHigh- (HR) and low-risk (LR) participants (N = 99; ages 52-71 years) were recruited from the Mass General Brigham Biobank. HR participants have genetic risk (APOE4) plus hypertension, type 2 diabetes, and/or depression; LR participants have no genetic or clinical risk. Participants underwent neuropsychological assessments of verbal, associative, and working memory, functional MRI (fMRI) scans while completing a working memory and verbal encoding task, and PET imaging scans. Aβ deposition was detected using PET C-11PiB and calculated as distribution volume ratio.ResultsHR status was significantly associated with lower scores in associative memory, altered fMRI BOLD activity in memory circuitry regions, and higher Aβ deposition, primarily in women. Further, altered task-based fMRI activity was related to worse memory performance and higher Aβ accumulation in women. While some effects were observed in men, effect sizes were smaller and did not survive correction for multiple comparisons.ConclusionsResults demonstrated that genetic and clinical risk factors can help identify in a sex-dependent manner those in midlife who are at increased risk of developing AD to target for early intervention.

Multiple sclerosis (MS) involves dysregulation of innate immune cells including monocytes, especially in progressive MS. Fatty acid binding proteins (FABP) are essential for fatty acid transport and metabolism in multiple cell types. FABP7, a brain-FABP, maintains metabolic function in astrocytes and neural stem cells, but the effect of FABP7 on monocytes is unknown. Here we find elevated levels of FABP7 in the serum and cerebrospinal fluid of patients with secondary progressive MS. Elevated serum FABP7 levels positively correlate with higher disability scores, brain lesion volumes, and lower brain volumes. FABP7 levels are increased in astrocytes from MS postmortem brain lesion. Mechanistically, in vitro treatment of FABP7 induces CD16, CD80 and IL-1β expression in monocytes via increased glycolysis. FABP7-induced gene expression reflects enhanced inflammation, chemotaxis and glucose metabolism in monocytes. In conclusion, we find that FABP7 induces pro-inflammatory profiles in monocytes, correlates with disability and represents a potential biomarker and therapeutic target for progressive MS.

Objective: To investigate the in vitro activation of NF-κB (nuclear factor kappa B) and STAT3 pathways in central memory CD4+ T (CD45RACD62L+, Tcm) cells of MOGAD patients after antigen and cytokine stimulation or glucocorticoid treatment compared to age-matched healthy controls (HC). Background: There is increasing evidence that T cells play a key role in MOGAD. Proinflammatory cytokines IL6 and TNFα, activators of STAT3 and NF-κB pathways, respectively, are reported to increase in CSF of MOGAD patients and increase during infections, which commonly precede MOGAD relapses, We previously found decreased A20, a negative regulator of NF-κB, serum levels at relapse. Design/Methods: 4 pediatric MOGAD remission samples (untreated) and 4 sex and age-matched HC were studied. 8×104 PBMCs were plated per well. Cells were stimulated with MOG peptides, anti-CD3/CD28, TNFα, IL6, or PMA/Ionomycin. A20, IκBα (inhibitor kappa B-alpha), p-p65 (phospho-p65), and p-STAT3 (phospho-STAT3) expression levels (MFI, mean fluorescence intensity) were determined by flow cytometry and MFI levels in Tcm. Results: Ex vivo expression levels of A20, IκBα, p-p65, and p-STAT3 levels were not significantly different in MOGAD compared to HC in Tcm. Upon short IL6 or TNFα (0–15/7–75 minutes) stimulation, we observed similar NF-κB and STAT3 activation in the Tcm, while STAT3 activation was significantly higher at 75 minutes in MOGAD. MOG peptide stimulation for 24 hours decreased A20 and IκBα levels and increased p-STAT3 and p-p65 levels in both MOGAD and HC. When co-incubated with either MOG peptide or CD3, prednisolone decreased NF-κB and STAT3 activation. Conclusions: MOG peptide stimulation activates STAT3 and NF-κB in CD4+Tcm cells from MOGAD and HC, while prednisolone treatment had the opposite effect. IL6 and TNFα also activate Tcm similarly in MOGAD and HC, while STAT3 activation was more extended in MOGAD. Modulating the NF-κB-A20 or IL6/STAT3 pathway in T cells may have therapeutic potential in MOGAD. Disclosure: Mr. Corbali has nothing to disclose. Shrishti Saxena has nothing to disclose. Dr. Patel has nothing to disclose. Dr. Chitnis has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Novartis. Dr. Chitnis has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Roche-Genentech. Dr. Chitnis has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Academic CME. The institution of Dr. Chitnis has received research support from Novartis. The institution of Dr. Chitnis has received research support from Sanofi. The institution of Dr. Chitnis has received research support from Octave.

Background Multiple sclerosis (MS) is a disabling autoimmune demyelinating disorder affecting young people and causing significant disability. In the last decade, different microRNA (miRNA) expression patterns have been associated to several treatment response therapies such as interferon and glatiramer acetate. Nowadays, there is increasing interest in the potential role of miRNA as treatment response biomarkers to the most recent oral and intravenous treatments. In this study, we aimed to evaluate serum miRNAs as biomarkers of No Evidence of Disease Activity (NEDA-3) at 2 years in patients with relapsing remitting MS (RRMS) treated with fingolimod. Main body A Discovery cohort of 31 RRMS patients treated with fingolimod were identified from the CLIMB study and classified as No Evidence of Disease Activity (NEDA-3) or Evidence of Disease Activity (EDA-3) after 2 years on treatment. Levels of miRNA expression were measured at 6 months using human serum miRNA panels and compared in EDA-3 and NEDA-3 groups using the Wilcoxon rank sum test. A set of differentially expressed miRNA was further validated in an independent cohort of 22 fingolimod-treated patients. We found that 548a-3p serum levels were higher levels in fingolimod-treated patients classified as NEDA-3, compared to the EDA-3 group in both the Discovery ( n = 31; p = 0.04) and Validation ( n = 22; p = 0.03) cohorts 6 months after treatment initiation; miR-548a-3p provided an AUC of 0.882 discriminating patients with NEDA-3 at 2 years in the Validation cohort. Conclusion Our results show differences in miR-548a-3p expression at 6 months after fingolimod start in patients with MS with NEDA-3 at 2 years. These results provide class III evidence of the use of miR-548a-3p as biomarker of NEDA-3 in patients with fingolimod.

In this study, we examined CD4 T cell activation using various stimuli in pediatric MOGAD patients (n = 4, untreated remission samples) and healthy controls (n = 5), to understand how both antigen-specific and bystander mechanisms contribute to CD4 T cell activation in MOGAD. TNFα, IL6, and MOG peptide pool were found to activate NF-κB or STAT3 pathways by measuring the expression of regulators (A20, IκBα) and phosphorylated subunits (phospho-p65 and phospho-STAT3) using immunolabeling. Prednisolone reversed activation of both NF-κB and STAT3 and increased the expression of A20 and IκBα. TNFR blocking partially reversed NF-κB activation in certain CD4 T cell subsets, but did not effect STAT3 activation. We observed that activation of NF-κB and STAT3 in response to various stimuli behaves mostly same in MOGAD (remission) and HC. IL6 stimulation resulted in higher STAT3 phosphorylation in MOGAD patients at 75 min, specifically in central and effector memory CD4 T cells (with unadjusted p-values). These findings suggest the potential therapeutic targeting of NF-κB and STAT3 pathways in MOGAD. Further investigation is needed to validate the significance of extended STAT3 phosphorylation and its correlation with IL6 receptor blocker treatment response.