Browsing by Author "Sanda, Srinath"

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    Defects in IL-2R Signaling Contribute to Diminished Maintenance of FOXP3 Expression in CD4+CD25+ Regulatory T-Cells of Type 1 Diabetic Subjects
    (American Diabetes Association, 2010-02) Long, S. Alice; Cerosaletti, Karen; Bollyky, Paul L.; Tatum, Megan; Shilling, Heather; Zhang, Sheng; Zhang, Zhong-Yin; Pihoker, Catherine; Sanda, Srinath; Greenbaum, Carla; Buckner, Jane H.; Biochemistry and Molecular Biology, School of Medicine
    OBJECTIVE In humans, multiple genes in the interleukin (IL)-2/IL-2 receptor (IL-2R) pathway are associated with type 1 diabetes. However, no link between IL-2 responsiveness and CD4+CD25+FOXP3+ regulatory T-cells (Tregs) has been demonstrated in type 1 diabetic subjects despite the role of these IL-2–dependent cells in controlling autoimmunity. Here, we address whether altered IL-2 responsiveness impacts persistence of FOXP3 expression in Tregs of type 1 diabetic subjects. RESEARCH DESIGN AND METHODS Persistence of Tregs was assessed by culturing sorted CD4+CD25hi natural Tregs with IL-2 and measuring FOXP3 expression over time by flow cytometry for control and type 1 diabetic populations. The effects of IL-2 on FOXP3 induction were assessed 48 h after activation of CD4+CD25− T-cells with anti-CD3 antibody. Cytokine receptor expression and signaling upon exposure to IL-2, IL-7, and IL-15 were determined by flow cytometry and Western blot analysis. RESULTS Maintenance of FOXP3 expression in CD4+CD25+ Tregs of type 1 diabetic subjects was diminished in the presence of IL-2, but not IL-7. Impaired responsiveness was not linked to altered expression of the IL-2R complex. Instead, IL-2R signaling was reduced in Tregs and total CD4+ T-cells of type 1 diabetic subjects. In some individuals, decreased signal transducer and activator of transcription 5 phosphorylation correlated with significantly higher expression of protein tyrosine phosphatase N2, a negative regulator of IL-2R signaling. CONCLUSIONS Aberrant IL-2R signaling in CD4+ T-cells of type 1 diabetic subjects contributes to decreased persistence of FOXP3 expression that may impact establishment of tolerance. These findings suggest novel targets for treatment of type 1 diabetes within the IL-2R pathway and suggest that an altered IL-2R signaling signature may be a biomarker for type 1 diabetes.
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    IL-6 receptor blockade does not slow β cell loss in new-onset type 1 diabetes
    (American Society for Clinical Investigation, 2021) Greenbaum, Carla J.; Serti, Elisavet; Lambert, Katharina; Weiner, Lia J.; Kanaparthi, Sai; Lord, Sandra; Gitelman, Stephen E.; Wilson, Darrell M.; Gaglia, Jason L.; Griffin, Kurt J.; Russell, William E.; Raskin, Philip; Moran, Antoinette; Willi, Steven M.; Tsalikian, Eva; DiMeglio, Linda A.; Herold, Kevan C.; Moore, Wayne V.; Goland, Robin; Harris, Mark; Craig, Maria E.; Schatz, Desmond A.; Baidal, David A.; Rodriguez, Henry; Utzschneider, Kristina M.; Nel, Hendrik J.; Soppe, Carol L.; Boyle, Karen D.; Cerosaletti, Karen; Keyes-Elstein, Lynette; Long, S. Alice; Thomas, Ranjeny; McNamara, James G.; Buckner, Jane H.; Sanda, Srinath; ITN058AI EXTEND Study Team; Pediatrics, School of Medicine
    Background: IL-6 receptor (IL-6R) signaling drives development of T cell populations important to type 1 diabetes pathogenesis. We evaluated whether blockade of IL-6R with monoclonal antibody tocilizumab would slow loss of residual β cell function in newly diagnosed type 1 diabetes patients. Methods: We conducted a multicenter, randomized, placebo-controlled, double-blind trial with tocilizumab in new-onset type 1 diabetes. Participants were screened within 100 days of diagnosis. Eligible participants were randomized 2:1 to receive 7 monthly doses of tocilizumab or placebo. The primary outcome was the change from screening in the mean AUC of C-peptide collected during the first 2 hours of a mixed meal tolerance test at week 52 in pediatric participants (ages 6–17 years). Results: There was no statistical difference in the primary outcome between tocilizumab and placebo. Immunophenotyping showed reductions in downstream signaling of the IL-6R in T cells but no changes in CD4 memory subsets, Th17 cells, Tregs, or CD4+ T effector cell resistance to Treg suppression. A DC subset decreased during therapy but regressed to baseline once therapy stopped. Tocilizumab was well tolerated. Conclusion: Tocilizumab reduced T cell IL-6R signaling but did not modulate CD4+ T cell phenotypes or slow loss of residual β cell function in newly diagnosed individuals with type 1 diabetes.
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    Imatinib therapy for patients with recent-onset type 1 diabetes: a multicentre, randomised, double-blind, placebo-controlled, phase 2 trial
    (Elsevier, 2021) Gitelman, Stephen E.; Bundy, Brian N.; Ferrannini, Ele; Lim, Noha; Blanchfield, J. Lori; DiMeglio, Linda A.; Felner, Eric I.; Gaglia, Jason L.; Gottlieb, Peter A.; Long, S. Alice; Mari, Andrea; Mirmira, Raghavendra G.; Raskin, Philip; Sanda, Srinath; Tsalikian, Eva; Wentworth, John M.; Willi, Steven M.; Krischer, Jeffrey P.; Bluestone, Jeffrey A.; Gleevec Trial Study Group; Pediatrics, School of Medicine
    Background: Type 1 diabetes results from autoimmune-mediated destruction of β cells. The tyrosine kinase inhibitor imatinib might affect relevant immunological and metabolic pathways, and preclinical studies show that it reverses and prevents diabetes. Our aim was to evaluate the safety and efficacy of imatinib in preserving β-cell function in patients with recent-onset type 1 diabetes. Methods: We did a multicentre, randomised, double-blind, placebo-controlled, phase 2 trial. Patients with recent-onset type 1 diabetes (<100 days from diagnosis), aged 18-45 years, positive for at least one type of diabetes-associated autoantibody, and with a peak stimulated C-peptide of greater than 0·2 nmol L-1 on a mixed meal tolerance test (MMTT) were enrolled from nine medical centres in the USA (n=8) and Australia (n=1). Participants were randomly assigned (2:1) to receive either 400 mg imatinib mesylate (4 × 100 mg film-coated tablets per day) or matching placebo for 26 weeks via a computer-generated blocked randomisation scheme stratified by centre. Treatment assignments were masked for all participants and study personnel except pharmacists at each clinical site. The primary endpoint was the difference in the area under the curve (AUC) mean for C-peptide response in the first 2 h of an MMTT at 12 months in the imatinib group versus the placebo group, with use of an ANCOVA model adjusting for sex, baseline age, and baseline C-peptide, with further observation up to 24 months. The primary analysis was by intention to treat (ITT). Safety was assessed in all randomly assigned participants. This study is registered with ClinicalTrials.gov, NCT01781975 (completed). Findings: Patients were screened and enrolled between Feb 12, 2014, and May 19, 2016. 45 patients were assigned to receive imatinib and 22 to receive placebo. After withdrawals, 43 participants in the imatinib group and 21 in the placebo group were included in the primary ITT analysis at 12 months. The study met its primary endpoint: the adjusted mean difference in 2-h C-peptide AUC at 12 months for imatinib versus placebo treatment was 0·095 (90% CI -0·003 to 0·191; p=0·048, one-tailed test). This effect was not sustained out to 24 months. During the 24-month follow-up, 32 (71%) of 45 participants who received imatinib had a grade 2 severity or worse adverse event, compared with 13 (59%) of 22 participants who received placebo. The most common adverse events (grade 2 severity or worse) that differed between the groups were gastrointestinal issues (six [13%] participants in the imatinib group, primarily nausea, and none in the placebo group) and additional laboratory investigations (ten [22%] participants in the imatinib group and two [9%] in the placebo group). Per the trial protocol, 17 (38%) participants in the imatinib group required a temporary modification in drug dosing and six (13%) permanently discontinued imatinib due to adverse events; five (23%) participants in the placebo group had temporary modifications in dosing and none had a permanent discontinuation due to adverse events. Interpretation: A 26-week course of imatinib preserved β-cell function at 12 months in adults with recent-onset type 1 diabetes. Imatinib might offer a novel means to alter the course of type 1 diabetes. Future considerations are defining ideal dose and duration of therapy, safety and efficacy in children, combination use with a complimentary drug, and ability of imatinib to delay or prevent progression to diabetes in an at-risk population; however, careful monitoring for possible toxicities is required.