Yazhong Tao

Differential Reconstitution of T Cell Subsets following Immunodepleting Treatment with Alemtuzumab (Anti-CD52 Monoclonal Antibody) in Patients with Relapsing–Remitting Multiple Sclerosis

Alemtuzumab (anti-CD52 mAb) provides long-lasting disease activity suppression in relapsing–remitting multiple sclerosis (RRMS). The objective of this study was to characterize the immunological reconstitution of T cell subsets and its contribution to the prolonged RRMS suppression following alemtuzumab-induced lymphocyte depletion. The study was performed on blood samples from RRMS patients enrolled in the CARE-MS II clinical trial, which was recently completed and led to the submission of alemtuzumab for U.S. Food and Drug Administration approval as a treatment for RRMS. Alemtuzumab-treated patients exhibited a nearly complete depletion of circulating CD4+ lymphocytes at day 7. During the immunological reconstitution, CD4+CD25+CD127low regulatory T cells preferentially expanded within the CD4+ lymphocytes, reaching their peak expansion at month 1. The increase in the percentage of TGF-β1–, IL-10–, and IL-4–producing CD4+ cells reached a maximum at month 3, whereas a significant decrease in the percentages of Th1 and Th17 cells was detected at months 12 and 24 in comparison with the baseline. A gradual increase in serum IL-7 and IL-4 and a decrease in IL-17A, IL-17F, IL-21, IL-22, and IFN-γ levels were detected following treatment. In vitro studies have demonstrated that IL-7 induced an expansion of CD4+CD25+CD127low regulatory T cells and a decrease in the percentages of Th17 and Th1 cells. In conclusion, our results indicate that differential reconstitution of T cell subsets and selectively delayed CD4+ T cell repopulation following alemtuzumab-induced lymphopenia may contribute to its long-lasting suppression of disease activity.

Simvastatin Inhibits IFN Regulatory Factor 4 Expression and Th17 Cell Differentiation in CD4+ T Cells Derived from Patients with Multiple Sclerosis

Subsequent to the clinical trial of simvastatin in patients with relapsing remitting multiple sclerosis (RR MS), which demonstrated the ability of simvastatin to inhibit new inflammatory CNS lesion formation, the current in vitro study has characterized the mechanisms through which simvastatin inhibits Th17 cell differentiation. The anti-inflammatory effects of statins are mediated by the inhibition of isoprenylation, which ensures proper membrane insertion and function of proteins. Small GTPases, involved in multiple signal transduction pathways, are the key targets for isoprenylation. We report that simvastatin, one of the most hydrophobic statins with good CNS penetration, inhibited Th17 cell differentiation and IL-17A, IL-17F, IL-21, and IL-22 secretion in in vitro-differentiated naive CD4+ T cells from RR MS patients. Simvastatin exerted a less prominent effect on the cells from healthy controls, as it inhibited only IL-17F secretion. The inhibition of Th17 cell differentiation was mediated via inhibition of IFN regulatory factor 4 (IRF4) expression, which was identified as a key transcription factor for human Th17 cell differentiation using both IRF4 gene knockdown and overexpression experiments. In studies addressing which isoprenylation pathway—geranylgeranylation or farnesylation—is inhibited by simvastatin, we demonstrated that the geranylgeranyl transferase inhibitor replicated the effect of simvastatin. Selective inhibition of geranylgeranylated RhoA-associated kinase replicated the effect of simvastatin on the inhibition of IRF4 expression and IL-17A, IL-17F, IL-21, and IL-22 secretion, presenting a promising new therapeutic approach for this disabling disease.

The Role of Endogenous IFN-β in the Regulation of Th17 Responses in Patients with Relapsing-Remitting Multiple Sclerosis

IFN-β has been used as a first-line therapy for relapsing-remitting multiple sclerosis (RRMS). Because only a few studies have addressed the role of endogenous IFN-β in the pathogenesis of the disease, our objective was to characterize its role in the transcriptional regulation of pathogenic Th17 cytokines in patients with RRMS. In vitro studies have demonstrated that IFN-β inhibits IL-17A, IL-17F, IL-21, IL-22, and IFN-γ secretion in CD4+ lymphocytes through the induction of suppressor of cytokine secretion 1 and suppressor of cytokine secretion 3. We found that patients with RRMS have increased serum and cerebrospinal fluid Th17 (IL-17A and IL-17F) cytokine levels in comparison with the control subjects, suggesting that deficient endogenous IFN-β secretion or signaling can contribute to the dysregulation of those pathogenic cytokines in CD4+ cells. We identified that the endogenous IFN-β from serum of RRMS patients induced a significantly lower IFN-inducible gene expression in comparison with healthy controls. In addition, in vitro studies have revealed deficient endogenous and exogenous IFN-β signaling in the CD4+ cells derived from patients with MS. Interestingly, upon inhibition of the endogenous IFN-β signaling by silencing IFN regulatory factor (IRF) 7 gene expression, the resting CD4+ T cells secreted significantly higher level of IL-17A, IL-17F, IL-21, IL-22, and IL-9, suggesting that endogenous IFN-β suppresses the secretion of these pathogenic cytokines. In vivo recombinant IFN-β–1a treatment induced IFNAR1 and its downstream signaling molecules’ gene expression, suggesting that treatment reconstitutes a deficient endogenous IFN-β regulation of the CD4+ T cells’ pathogenic cytokine production in patients with MS.

Simvastatin inhibits secretion of Th17-polarizing cytokines and antigen presentation by DCs in patients with relapsing remitting multiple sclerosis

Statins, widely used cholesterol‐lowering agents, have also been demonstrated to have antiinflammatory effects. Here, we characterize the capacity of simvastatin to target DCs and modulate T‐cell priming and Th17‐cell differentiation, in a cohort of patients with relapsing remitting multiple sclerosis (RRMS). We report that simvastatin inhibits IL‐1β, IL‐23, TGF‐β, IL‐21, IL‐12p70, and induces IL‐27 secretion from DCs in RRMS patients, providing an inhibitory cytokine milieu for Th17 and Th1‐cell differentiation. The effect on DCs is mediated via induction of SOCS1, SOCS3, and SOCS7 gene expression, which are associated with the inhibition of STAT1, STAT3, and ERK1/2 phosphorylation. A geranylgeranyl transferase inhibitor replicated simvastatins effects on DC cytokine secretion, implicating that simvastatin‐induced depletion of isoprenoids mediates this effect. Simvastatin inhibited antigen presentation by DCs via suppression of the MHC class I expression, costimulatory molecules CD80 and CD40, and by inducing a dramatic loss of dendritic processes. The changes in DC morphology were also mediated via inhibition of geranylgeranylation. The therapeutic use of geranylgeranylation inhibitors may provide selective inhibition of key pathogenic cytokines that drive the autoimmune response in MS; their use represents a promising therapeutic approach that requires further clinical testing.

IL-11 Induces Th17 Cell Responses in Patients with Early Relapsing-Remitting Multiple Sclerosis

Clinically isolated syndrome (CIS) suggestive of multiple sclerosis (MS) is the earliest clinically evident phase of the disease, which may provide valuable insight into the molecular mechanisms of the initiation of the autoimmune response in MS. Our results introduce IL-11 as a new cytokine that plays a role in the autoimmune response in the early phase of the disease. IL-11 is the highest upregulated cytokine in the sera and cerebrospinal fluid from CIS patients, which is also increased in patients with clinically definitive relapsing-remitting MS in comparison with healthy control subjects. Serum IL-11 levels are significantly increased during clinical exacerbations in comparison with remissions in the same patients. CD4+ cells represent a predominant cell source of IL-11 in the peripheral circulation, and the percentage of IL-11+CD4+ cells is significantly increased in CIS patients in comparison with healthy control subjects. Furthermore, we have identified IL-11 as a new Th17-promoting cytokine, because it induces a differentiation of naive CD4+ T cells into Th17 cells, as well as expansion of Th17 memory cells. Because the Th17 cytokines IL-17F, IL-21 and TNF-α, and TGF-β induce differentiation of naive cells in the IL-11–secreting CD4+ cells, we propose that cross-talk between IL-11+CD4+ and Th17 cells may play a role in the inflammatory response in relapsing-remitting MS.

Immunologic and MRI markers of the therapeutic effect of IFN-β-1a in relapsing-remitting MS

Objectives: To assess potential roles of effector cells and immunologic markers in demyelinating CNS lesion formation, and their modulation by interferon β-1a (IFN-β-1a). Methods: Twenty-three patients with relapsing-remitting multiple sclerosis (RRMS) received IFN-β-1a for 6 months. Immunologic marker results were correlated with brain MRI lesion volumes, and volumes of normal-appearing brain tissue (NABT) with decreasing or increasing voxel-wise magnetization transfer ratio (VW-MTR), suggestive of demyelination and remyelination, respectively. Results: Baseline expression of Th22 cell transcription factor aryl hydrocarbon receptor (AHR) and interleukin (IL)-17F, and percentages of IL-22–expressing CD4+ and CD8+ cells, were significantly higher in patients vs 15 healthy controls; IL-4 in CD4+ cells was lower. Baseline percentage of IL-22–producing CD8+ cells positively correlated with T2 lesion volumes, while percentage of IL-17A–producing CD8+ cells positively correlated with T2 and T1 lesion volumes. IFN-β-1a induced reductions in transcription factor AHR, T-bet, and retinoic acid–related orphan nuclear hormone receptor C (RORc) gene expression, while it increased GATA3s expression in CD4+ cells. Percentages of IL-22-, IL-17A-, and IL-17F-expressing T cells significantly decreased following treatment. Increased percentages of IL-10–expressing CD4+ and CD8+ cells correlated with greater NABT volume with increasing VW-MTR, while decreased percentage of IL-17F–expressing CD4+ cells positively correlated with decreased NABT volume with decreasing VW-MTR. Conclusions: Findings indicate that IFN-β-1a suppresses Th22 and Th17 cell responses, which were associated with decreased MRI-detectable demyelination. Classification of evidence: This pilot study provides Class III evidence that reduced Th22 and Th17 responses are associated with decreased demyelination following IFN-β-1a treatment in patients with RRMS.

Toll-like receptor (TLR)7 and TLR9 agonists enhance interferon (IFN) beta-1a's immunoregulatory effects on B cells in patients with relapsing-remitting multiple sclerosis (RRMS)

We report that B cells from patients with RRMS have decreased endogenous IFN-β secretion and deficient IFN receptor (IFNAR)1/2 and TLR7 gene expression in comparison to healthy controls (HCs), which may contribute to disregulation of cytokine secretion by B cells. We propose that TLR7 and TLR9 stimulation with loxorubin (LOX) and CpG, in combination with exogenous IFN-β may effectively reconstitute endogenous IFN-β production deficit and induce the secretion of immunoregulatory cytokines by B cells. Both LOX/IFN-β and CpG/IFN-β in-vitro treatments of B cells from RRMS patients induced higher endogenous IFN-β gene expression in comparison to the exogenous IFN-β alone. CpG/IFN-β combination induced higher secretion of IL-10, TGF-β, and IL-27 in comparison to stimulation with IFN-β. Our study provides a basis for future clinical studies employing IFN-β and TLR7/9 agonists, which may enhance the resolution of the inflammatory response in RRMS.