Neither T-helper type 2 nor Foxp3 + regulatory T cells are necessary for therapeutic benefit of atorvastatin in treatment of central nervous system autoimmunity
TL;DR: Data imply that atorvastatin ameliorates central nervous system autoimmune disease primarily by inhibiting proliferation of proinflammatory encephalitogenic T cells, and not simply through induction of anti-inflammatory Th2 cells.
Abstract: Oral atorvastatin has prevented or reversed paralysis in the multiple sclerosis (MS) model experimental autoimmune encephalomyelitis (EAE), and reduced development of new MS lesions in clinical trials. Besides inhibiting development of encephalitogenic T cells, atorvastatin treatment of EAE has been associated with an induction of anti-inflammatory myelin-reactive T-helper type (Th)-2 cells. To investigate the clinical significance of atorvastatin-mediated Th2 differentiation, we first evaluated atorvastatin treatment in interleukin (IL)-4 green fluorescent protein-enhanced transcript (4-GET) reporter mice. Atorvastatin treatment failed to induce IL-4-producing Th2 cells in vivo; however, when T cells from atorvastatin-treated 4-GET mice were reactivated in vitro, T cells preferentially differentiated into Th2 cells, while antigen-specific T-cell proliferation and secretion of proinflammatory cytokines (interferon gamma, IL-17, tumor necrosis factor and IL-12) were reduced. Oral atorvastatin also prevented or reversed EAE in signal transducer and activator of transcription 6-deficient (STAT6−/−) mice, which cannot generate IL-4-producing Th2 cells. Further, atorvastatin treatment did not induce or expand Foxp3+ regulatory T cells in either wild-type or STAT6−/− mice. In vivo proliferation of T cells, as measured by incorporation of bromodeoxyuridine, was inhibited in atorvastatin-treated wild-type and STAT6−/− mice. These data imply that atorvastatin ameliorates central nervous system autoimmune disease primarily by inhibiting proliferation of proinflammatory encephalitogenic T cells, and not simply through induction of anti-inflammatory Th2 cells. This cytostatic effect may be a relevant mechanism of action when considering use of statins in MS and other inflammatory conditions.
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01 Jan 2018
TL;DR: Ch Chromosomal mutations found in MS patients as well as environmental factors influencing the expression of certain genes will be analyzed in this review.
Abstract: Multiple Sclerosis (MS) is an incurable autoimmune disorder that attacks the myelin sheath surrounding nerve cells. Steady demyelination of these cells over time results in painful inflammation and reduced mobility. Genetic abnormalities could be responsible for the onset of this disease. Chromosomal mutations found in MS patients as well as environmental factors influencing the expression of certain genes will be analyzed in this review. Moreover, treatments regulating gene expression in MS patients will be discussed. Further genetic research would not only provide scientists and medical professionals with a deeper understanding of MS and other autoimmune disorders, but also lead to the development of more effective treatments. Recent findings have enabled scientists to identify genes in MS patients that are absent in healthy patients, but researchers struggle to find a common thread tying these genes together. This is just one of the many reasons why MS is still considered an idiopathic disease.
TL;DR: In this article , the impact of interferon (IFN)-γ at the peak of EAE, its effects on CNS infiltrating myeloid cells (MC) and microglia (MG), and the underlying cellular and molecular mechanisms were investigated.
Abstract: Compelling evidence has shown that interferon (IFN)-γ has dual effects in multiple sclerosis and in its animal model of experimental autoimmune encephalomyelitis (EAE), with results supporting both a pathogenic and beneficial function. However, the mechanisms whereby IFN-γ may promote neuroprotection in EAE and its effects on central nervous system (CNS)-resident cells have remained an enigma for more than 30 years. In this study, the impact of IFN-γ at the peak of EAE, its effects on CNS infiltrating myeloid cells (MC) and microglia (MG), and the underlying cellular and molecular mechanisms were investigated. IFN-γ administration resulted in disease amelioration and attenuation of neuroinflammation associated with significantly lower frequencies of CNS CD11b+ myeloid cells and less infiltration of inflammatory cells and demyelination. A significant reduction in activated MG and enhanced resting MG was determined by flow cytometry and immunohistrochemistry. Primary MC/MG cultures obtained from the spinal cord of IFN-γ-treated EAE mice that were ex vivo re-stimulated with a low dose (1 ng/ml) of IFN-γ and neuroantigen, promoted a significantly higher induction of CD4+ regulatory T (Treg) cells associated with increased transforming growth factor (TGF)-β secretion. Additionally, IFN-γ-treated primary MC/MG cultures produced significantly lower nitrite in response to LPS challenge than control MC/MG. IFN-γ-treated EAE mice had a significantly higher frequency of CX3CR1high MC/MG and expressed lower levels of program death ligand 1 (PD-L1) than PBS-treated mice. Most CX3CR1highPD-L1lowCD11b+Ly6G- cells expressed MG markers (Tmem119, Sall2, and P2ry12), indicating that they represented an enriched MG subset (CX3CR1highPD-L1low MG). Amelioration of clinical symptoms and induction of CX3CR1highPD-L1low MG by IFN-γ were dependent on STAT-1. RNA-seq analyses revealed that in vivo treatment with IFN-γ promoted the induction of homeostatic CX3CR1highPD-L1low MG, upregulating the expression of genes associated with tolerogenic and anti-inflammatory roles and down-regulating pro-inflammatory genes. These analyses highlight the master role that IFN-γ plays in regulating microglial activity and provide new insights into the cellular and molecular mechanisms involved in the therapeutic activity of IFN-γ in EAE.
TL;DR: In this article, the efficacy of atorvastatin treatment in subjects not responding to hepatitis B vaccination and evaluating the possible molecular pathways included in the process was evaluated, and it was shown that short-term atoravastatin administration was associated with an increased level of HBsAb to that of protective levels against HB, but this response was not induced through the assessed immune pathways.
Abstract: Background: It is estimated that 10% of people receiving hepatitis B (HB) vaccination fail to produce a protective level of hepatitis B surface antibody (HBsAb). Various methods such as administration of immune-enhancing medications, increasing the dose of vaccine, or changing injection route are implemented to overcome this issue. Objectives: In this regard, to the current study aimed at assessing the efficacy of atorvastatin treatment in subjects not responding to HB vaccination and evaluating the possible molecular pathways included in the process. Methods: In the current clinical trial, healthy subjects with HBsAb titers of less than 10 IU/mL after a complete course of HB vaccination were included. Participants were randomly assigned into two groups of case and control. Subjects in the case group received daily atorvastatin (40 mg) tablets for 10 days, while the controls were given identical placebo tablets. On the 5th day all subjects received 1.0 mL intramuscular HB vaccine. Four to eight weeks after vaccination, blood samples were drawn from the participants for laboratory assessments including enzyme-linked immunosorbent assay (ELISA) to measure the level of HBsAb, interleukin (IL)-4, IL-17, interferon (IFN)-γ and transforming growth factor (TGF)-β cytokines, and real-time polymerase chain reaction (PCR) was also used to evaluate the expression of their corresponding genes; T-Bet, RORc, and GATA3. Results: A total of 30 subjects (five females and 25 males) were included, with 15 participants in each group. There was no significant difference between the two groups considering baseline characteristics of the participants. Final laboratory assessment of HBsAb levels revealed that 12 (80%) subjects from the case and 5 (33.3%) from the control groups produced a protective level of antibodies (P = 0.025). No significant difference was observed in the concentration of IL-4, IL-17, IFN-γ, and TGF-β, and the expression of their corresponding genes between the two groups. Conclusions: The study showed that short-term atorvastatin administration was associated with an increased level of HBsAb to that of protective levels against HB, but this response was not induced through the assessed immune pathways. Further investigations are required to identify the exact mechanism for this effect of atorvastatin.
TL;DR: Patients on simvastatin showed a 43 percent reduction in the annualized rate of brain atrophy compared with the placebo group, and despite the high dose, there were no differences in serious adverse effects between the two groups.
Abstract: simvastatin (Zocor), one of the most widely prescribed statins, appears to slow brain shrinkage in patients with secondary progressive multiple sclerosis (MS). Since brain shrinkage is the most reliable marker of worsening disease, the findings, if they hold up, could make simvastatin the first treatment capable of affecting the latestage disability that eventually affects about 65 percent of MS patients. “At the moment, we don’t have anything that can stop patients from becoming more disabled once MS reaches the progressive phase,” said co-author Richard Nicholas, MD, of the Faculty of Medicine at Imperial College London, in a statement released prior to the publication of the study in the March 19 online edition of The Lancet. “This is a promising finding, particularly as statins are already cheap and widely used. We need to do a bigger study with more patients, possibly starting in the earlier phase of the disease, to fully establish how effective it is.” The two-year, double-blinded, controlled trial involved 140 patients, ages 18 to 65, with secondary progressive MS. They were randomly assigned to receive either 80 mg of simvastatin or a placebo. Those on simvastatin showed a 43 percent reduction in the annualized rate of brain atrophy compared with the placebo group (-0.254 percent per year, p=0.003). Despite the high dose — the Food and Drug Administration warns against starting patients on 80 mg of simvastatin because of the risk of muscle damage — there were no differences in serious adverse effects between the two groups.
References
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TL;DR: It is shown that oral atorvastatin prevented or reversed chronic and relapsing paralysis and has pleiotropic immunomodulatory effects involving both APC and T-cell compartments.
Abstract: Statins, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, which are approved for cholesterol reduction, may also be beneficial in the treatment of inflammatory diseases. Atorvastatin (Lipitor) was tested in chronic and relapsing experimental autoimmune encephalomyelitis, a CD4(+) Th1-mediated central nervous system (CNS) demyelinating disease model of multiple sclerosis. Here we show that oral atorvastatin prevented or reversed chronic and relapsing paralysis. Atorvastatin induced STAT6 phosphorylation and secretion of Th2 cytokines (interleukin (IL)-4, IL-5 and IL-10) and transforming growth factor (TGF)-beta. Conversely, STAT4 phosphorylation was inhibited and secretion of Th1 cytokines (IL-2, IL-12, interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha) was suppressed. Atorvastatin promoted differentiation of Th0 cells into Th2 cells. In adoptive transfer, these Th2 cells protected recipient mice from EAE induction. Atorvastatin reduced CNS infiltration and major histocompatibility complex (MHC) class II expression. Treatment of microglia inhibited IFN-gamma-inducible transcription at multiple MHC class II transactivator (CIITA) promoters and suppressed class II upregulation. Atorvastatin suppressed IFN-gamma-inducible expression of CD40, CD80 and CD86 co-stimulatory molecules. l-Mevalonate, the product of HMG-CoA reductase, reversed atorvastatin's effects on antigen-presenting cells (APC) and T cells. Atorvastatin treatment of either APC or T cells suppressed antigen-specific T-cell activation. Thus, atorvastatin has pleiotropic immunomodulatory effects involving both APC and T-cell compartments. Statins may be beneficial for multiple sclerosis and other Th1-mediated autoimmune diseases.
1,082 citations
"Neither T-helper type 2 nor Foxp3 +..." refers background or methods in this paper
...myocarditis [5,6], experimental systemic lupus erythematosus [7] and experimental autoimmune encephalomyelitis (EAE) [2,8-10], the animal model for multiple sclerosis (MS)....
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...These doses have been previously shown to prevent EAE [2]....
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...Besides their metabolic properties, statins attracted interest for their immunomodulatory potential [2]....
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...We observed that in vivo AT treatment during EAE inhibited proliferation of myelin-specific T cells upon restimulation ex vivo [2,8] (Figure 4a), suggesting that these myelin-reactive cells expanded less in AT-treated mice post vaccination....
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...) was brought into suspension in phosphate-buffered saline as described previously [2]....
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TL;DR: The ability of dimethylfumarate to activate nuclear factor (erythroid-derived 2)-related factor 2 may offer a novel cytoprotective modality that further augments the natural antioxidant responses in multiple sclerosis tissue and is not yet targeted by other multiple sclerosis therapies.
Abstract: Inflammation and oxidative stress are thought to promote tissue damage in multiple sclerosis. Thus, novel therapeutics enhancing cellular resistance to free radicals could prove useful for multiple sclerosis treatment. BG00012 is an oral formulation of dimethylfumarate. In a phase II multiple sclerosis trial, BG00012 demonstrated beneficial effects on relapse rate and magnetic resonance imaging markers indicative of inflammation as well as axonal destruction. First we have studied effects of dimethylfumarate on the disease course, central nervous system, tissue integrity and the molecular mechanism of action in an animal model of chronic multiple sclerosis: myelin oligodendrocyte glycoprotein induced experimental autoimmune encephalomyelitis in C57BL/6 mice. In the chronic phase of experimental autoimmune encephalomyelitis, preventive or therapeutic application of dimethylfumarate ameliorated the disease course and improved preservation of myelin, axons and neurons. In vitro, the application of fumarates increased murine neuronal survival and protected human or rodent astrocytes against oxidative stress. Application of dimethylfumarate led to stabilization of the transcription factor nuclear factor (erythroid-derived 2)-related factor 2, activation of nuclear factor (erythroid-derived 2)-related factor 2-dependent transcriptional activity and accumulation of NADP(H) quinoline oxidoreductase-1 as a prototypical target gene. Furthermore, the immediate metabolite of dimethylfumarate, monomethylfumarate, leads to direct modification of the inhibitor of nuclear factor (erythroid-derived 2)-related factor 2, Kelch-like ECH-associated protein 1, at cysteine residue 151. In turn, increased levels of nuclear factor (erythroid-derived 2)-related factor 2 and reduced protein nitrosylation were detected in the central nervous sytem of dimethylfumarate-treated mice. Nuclear factor (erythroid-derived 2)-related factor 2 was also upregulated in the spinal cord of autopsy specimens from untreated patients with multiple sclerosis. In dimethylfumarate-treated mice suffering from experimental autoimmune encephalomyelitis, increased immunoreactivity for nuclear factor (erythroid-derived 2)-related factor 2 was detected by confocal microscopy in neurons of the motor cortex and the brainstem as well as in oligodendrocytes and astrocytes. In mice deficient for nuclear factor (erythroid-derived 2)-related factor 2 on the same genetic background, the dimethylfumarate mediated beneficial effects on clinical course, axon preservation and astrocyte activation were almost completely abolished thus proving the functional relevance of this transcription factor for the neuroprotective mechanism of action. We conclude that the ability of dimethylfumarate to activate nuclear factor (erythroid-derived 2)-related factor 2 may offer a novel cytoprotective modality that further augments the natural antioxidant responses in multiple sclerosis tissue and is not yet targeted by other multiple sclerosis therapies.
936 citations
"Neither T-helper type 2 nor Foxp3 +..." refers background in this paper
...factor (Nrf2) pathway [49,50], it also exerts anti-...
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TL;DR: Investigation of use of oral simvastatin in 30 individuals with relapsing-remitting multiple sclerosis found it to inhibit inflammatory components of multiple sclerosis that lead to neurological disability.
475 citations
"Neither T-helper type 2 nor Foxp3 +..." refers background in this paper
...How does this new information impact the potential use of statins in MS [42]? At first glance, nonspecific inhibition of proinflammatory T-cell differentiation in MS may be viewed less advantageously than the active induction of an anti-inflammatory T-cell phenotype [17,18,43]....
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...In the first placebo-controlled trial testing a statin as monotherapy in MS, atorvastatin (AT) significantly reduced the risk of developing new magnetic resonance imaging demyelinating lesions in patients with clinical isolated syndromes, but did not meet its primary endpoint that included reduction in conversion to clinically definite MS [17,18]....
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TL;DR: Reporter T cells primed under Th2 conditions showed sensitive and faithful EGFP expression and maintained endogenous IL-4, and reporter expression demonstrated the evolution of type 2 immunity from tissue lymphocytes and thence to lymph node CD4(+) T cells, which subsequently migrated into tissue.
439 citations
TL;DR: Adoptive transfer of type II monocytes reversed EAE, suppressed TH17 cell development and promoted both TH2 differentiation and expansion of Treg cells in recipient mice, identifying a central role for these cells in T cell immune modulation of autoimmunity.
Abstract: Treatment with glatiramer acetate (GA, copolymer-1, Copaxone), a drug approved for multiple sclerosis (MS), in a mouse model promoted development of anti-inflammatory type II monocytes, characterized by increased secretion of interleukin (IL)-10 and transforming growth factor (TGF)-beta, and decreased production of IL-12 and tumor necrosis factor (TNF). This anti-inflammatory cytokine shift was associated with reduced STAT-1 signaling. Type II monocytes directed differentiation of T(H)2 cells and CD4+CD25+FoxP3+ regulatory T cells (T(reg)) independent of antigen specificity. Type II monocyte-induced regulatory T cells specific for a foreign antigen ameliorated experimental autoimmune encephalomyelitis (EAE), indicating that neither GA specificity nor recognition of self-antigen was required for their therapeutic effect. Adoptive transfer of type II monocytes reversed EAE, suppressed T(H)17 cell development and promoted both T(H)2 differentiation and expansion of T(reg) cells in recipient mice. This demonstration of adoptive immunotherapy by type II monocytes identifies a central role for these cells in T cell immune modulation of autoimmunity.
436 citations
"Neither T-helper type 2 nor Foxp3 +..." refers background or result in this paper
...(b) The frequency of CD4+CD25+FoxP3+ regulatory T cells (Tregs) was evaluated by fluorescence-activated cell sorting....
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...However, it was not associated with an increase in CD4+CD25+FoxP3+ Tregs in either STAT6-deficient or wild-type mice....
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...A potential increase in Tregs is therefore unlikely to significantly contribute to the anti-inflammatory effect of statins in CNS autoimmune disease....
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...Induction of CD4+CD25+FoxP3+ Tregs was evaluated using a FACS staining kit by eBioscience....
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...Whether statins solely inhibit encephalitogenic T-cell differentiation or whether they may actively induce regulatory T-cell populations such as Th2 cells or Foxp3+ Tregs, considered a desirable goal in treatment of MS, thus remains to be investigated....
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