- Sphingolipid molecule sphingosine 1-phosphate (S1P) in regulating multiple physiological and pathophysiological processes including cell proliferation and survival, cell migration, inflammatory mediator synthesis and tissue remodeling.
Life Sci. 2019 Jan 15;217:243-250. doi: 10.1016/j.lfs.2018.12.019. Epub 2018 Dec 11.
FTY720 inhibits the activation of pancreatic stellate cells by promoting apoptosis and suppressing autophagy via the AMPK/mTOR pathway.
Pancreatic stellate cells (PSCs) play a critical role in the development of pancreatic fibrosis. Any agents that can affect PSC activation could become potential candidates for treating pancreatic fibrosis. FTY720 can attenuate chronic pancreatic fibrosis by suppressing T-cell infiltration, but its effect on PSCs remains unknown. This study was conducted to investigate the effects of FTY720 on PSC activation in cultured rat PSCs.
The viability of PSCs after FTY720 treatment was detected by MTT. Cell proliferation and migration analysis was performed using the iCELLigence System and a Transwell assay. Cell apoptosis was assessed by flow cytometry, western blot and an activity assay. The mitochondrial membrane potential (MMP) was assessed by JC-1 staining. The expression of α-SMA, collagen I, fibronectin, Beclin-1, Atg5, P62 and LC3B were analysed by immunofluorescence, quantitative real-time PCR and western blot. Rapamycin and phenformin hydrochloride were used to determine whether FTY720 inhibits PSC autophagy by the AMPK/mTOR pathway.
FTY720 supressed PSC viability, proliferation and migration. FTY720 inhibited PSC activation, induced PSC apoptosis and supressed PSC autophagy. We also confirmed that FTY720 inhibited PSC autophagy via the AMPK/mTOR pathway.
Our results indicated that FTY720 inhibited PSC activation by promoting cell apoptosis and inhibiting PSC autophagy by suppressing AMPK and activating the mTOR pathway.
These findings may explain the therapeutic mechanisms of FTY720 in treating pancreatic fibrosis and further suggest that targeting autophagy and the related signalling pathways may provide new strategies for the treatment of pancreatic fibrosis.
J Cell Physiol. 2019 Mar 6. doi: 10.1002/jcp.28434. [Epub ahead of print]
FTY720 alleviates coxsackievirus B3-induced myocarditis and inhibits viral replication through regulating sphingosine 1-phosphate receptors and AKT/caspase-3 pathways.
Fingolimod (FTY720) after phosphorylation, as the ligand of sphingosine 1-phosphate receptors (S1PRs), plays an important role in cell proliferation and differentiation. In this article, FTY720 in the treatment of coxsackievirus B3 (CVB3)-induced viral myocarditis was closely related to apoptosis and AKT/caspase-3 apoptotic pathways. We found that CVB3 inhibited myocardial apoptosis at the early stage with upregulating p-AKT level and downregulating activated caspase-3 level for replication of virus progeny, whereas it promoted apoptosis at a late stage with downregulating p-AKT and upregulating activated caspase-3 for releasing the newly synthesized virus to spread. Interestingly, FTY720 could reverse this trend; it promoted apoptosis at an early stage and inhibited apoptosis at the late stage in vivo and vitro, which proved the antiviral effect. We also found that S1PR1, S1PR4, and S1PR5, rather than S1PR2 and S1PR3, were regulated by FTY720 in this process. The results confirmed that FTY720 alleviates CVB3-induced myocarditis and inhibits viral replication through regulating S1PRs and AKT/caspase-3 pathways with a bidirectional regulation of apoptosis.
J Neuroinflammation. 2019 Mar 2;16(1):54. doi: 10.1186/s12974-019-1441-4.
FTY720 controls disease severity and attenuates sciatic nerve damage in chronic experimental autoimmune neuritis.
Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an autoimmune-mediated inflammatory disease of the peripheral nervous system characterized by a response directed against certain myelin proteins and for which therapies are limited. Previous studies have suggested a beneficial role of FTY720, a sphingosine 1-phosphate (S1P) receptor agonist, known to deplete lymphocytes from the peripheral blood by sequestering them into lymph nodes, in the treatment of experimental autoimmune neuritis (EAN). Therefore, we investigated whether FTY720 is also beneficial in chronic experimental autoimmune neuritis (c-EAN), a recently developed rat model mimicking human CIDP.
c-EAN was induced in Lewis rats by immunization with S-palm P0(180-199) peptide. Rats were treated with FTY720 (1 mg/kg) or vehicle intraperitoneally once daily from the onset of clinical signs for 18 days; clinical signs were assessed daily until 60 days post-immunization (dpi). Electrophysiological and histological features were examined at different time points. We also evaluated the serum levels of different pro- and anti-inflammatory cytokines by ELISA or flow cytometry at 18, 40, and 60 dpi.
Our data demonstrate that FTY720 decreased the severity and abolished the chronicity of the disease in c-EAN rats. Therapeutic FTY720 treatment reversed electrophysiological and histological anomalies, suggesting that myelinated fibers were subsequently preserved, it inhibited macrophage and IL-17+ cell infiltration in PNS, and it significantly reduced circulating pro-inflammatory cytokines.
FTY720 treatment has beneficial effects on c-EAN, a new animal model mimicking human CIDP. We have shown that FTY720 is an effective immunomodulatory agent, improving the disease course of c-EAN, preserving the myelinated fibers, attenuating the axonal degeneration, and decreasing the number of infiltrated inflammatory cells in peripheral nerves. These data confirm the interest of testing FTY720 or molecules targeting S1P in human peripheral neuropathies.
J Pain. 2019 Feb 23. pii: S1526-5900(18)30585-6. doi: 10.1016/j.jpain.2019.02.007. [Epub ahead of print]
Activation of Sphingosine-1-Phosphate Receptor 1 in the Spinal Cord Produces Mechanohypersensitivity Through the Activation of Inflammasome and IL-1β Pathway.
Sphingosine-1-phosphate (S1P) receptor 1 subtype (S1PR1) activation by its ligand S1P in the dorsal horn of the spinal cord causes mechano-hypersensitivity.
The cellular and molecular pathways remain poorly understood. We report that the activation of S1PR1 with an intrathecal injection of the highly selective S1PR1 agonist SEW2871 led to the development of mechanoallodynia by activating the nod-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome (increased expression of NLRP3, cleaved caspase 1 and mature IL-1β) in the dorsal horn of the spinal cord. The functional S1PR1 antagonist FTY720 blocked NLRP3 activation and IL-1β production.
Moreover, inhibiting IL-10 signaling with an intrathecal injection of an anti-IL-10 antibody attenuated the beneficial effects exerted by FTY720. This finding suggests that disrupting S1PR1 signaling engages beneficial IL-10-dependent pathways. Notably, we found that mice with astrocyte-specific deletions of S1pr1 did not develop mechanoallodynia after intrathecal injection of SEW2871 and exhibited decreased levels of cleaved caspase 1, identifying astrocytes as a key cellular locus for S1PR1 activity. Our findings provide novel mechanistic insights on how S1PR1 activation in the spinal cord contributes to the development of nociception while identifying the cellular substrate for these activities.
PERSPECTIVE: This study is the first to link the activation of NLRP3 and IL-1β signaling in the spinal cord and S1PR1 signaling in astrocytes to the development of S1PR1-evoked mechanoallodynia. These findings provide critical basic science insights to support the development of therapies targeted toward S1PR1.
Pharmacol Res. 2019 Feb 15. pii: S1043-6618(18)32039-5. doi: 10.1016/j.phrs.2019.02.009. [Epub ahead of print]
Targeting the S1P receptor signaling pathways as a promising approach for treatment of autoimmune and inflammatory diseases.
The past two decades of intense research have revealed a key role of the sphingolipid molecule sphingosine 1-phosphate (S1P) in regulating multiple physiological and pathophysiological processes including cell proliferation and survival, cell migration, inflammatory mediator synthesis and tissue remodeling. S1P mainly acts through five high-affinity G protein-coupled S1P receptors, which are ubiquitously expressed and mediate a complex network of signaling in a cell type dependent manner. S1P receptors have become an attractive pharmacological target to interfere with S1P-mediated cellular responses, which contribute to various autoimmune and inflammatory diseases. Pioneering in this field was the synthesis of FTY720 (fingolimod, Gilenya®) from myriocin, one of the metabolites of the fungus Isaria sinclairii known from traditional Chinese medicine for its antibacterial and energy boosting effect. Fingolimod turned out as a very potent immunomodulatory agent that subsequently passed all clinical trials successfully and is now approved for the treatment of relapsing-remitting multiple sclerosis. Pharmacologically, fingolimod was characterized as a non-selective agonist of all of the S1P receptors (S1PR), with the exception of S1P2, and in addition, as a selective S1P1 functional antagonist by induction of irreversible S1P1 internalization and degradation. Since proper lymphocyte trafficking depends on the expression of S1P1 on lymphocytes, the degradation of S1P1 leads to trapping and accumulation of lymphocytes in secondary lymphoid tissue, and consequently to a depletion of lymphocytes from the blood. Novel S1PR modulators are now being developed with a more selective receptor activation profile and improved pharmacokinetic characteristics. In this review, we will summarize the state-of-the-art approaches that target directly or indirectly S1P signaling and may be useful as novel strategies to treat autoimmune and inflammatory diseases.
Mol Neurobiol. 2019 Jan 30. doi: 10.1007/s12035-019-1481-x. [Epub ahead of print]
Fingolimod Suppresses the Proinflammatory Status of Interferon-γ-Activated Cultured Rat Astrocytes.
Astroglia, the primary homeostatic cells of the central nervous system, play an important role in neuroinflammation. They act as facultative immunocompetent antigen-presenting cells (APCs), expressing major histocompatibility complex (MHC) class II antigens upon activation with interferon (IFN)-γ and possibly other proinflammatory cytokines that are upregulated in disease states, including multiple sclerosis (MS).
We characterized the anti-inflammatory effects of fingolimod (FTY720), an established drug for MS, and its phosphorylated metabolite (FTY720-P) in IFN-γ-activated cultured rat astrocytes. The expression of MHC class II compartments, β2 adrenergic receptor (ADR-β2), and nuclear factor kappa-light-chain enhancer of activated B cells subunit p65 (NF-κB p65) was quantified in immunofluorescence images acquired by laser scanning confocal microscopy. In addition, MHC class II-enriched endocytotic vesicles were labeled by fluorescent dextran and their mobility analyzed in astrocytes subjected to different treatments. FTY720 and FTY720-P treatment significantly reduced the number of IFN-γ-induced MHC class II compartments and substantially increased ADR-β2 expression, which is otherwise small or absent in astrocytes in MS.
These effects could be partially attributed to the observed decrease in NF-κB p65 expression, because the NF-κB signaling cascade is activated in inflammatory processes. We also found attenuated trafficking and secretion from dextran-labeled endo-/lysosomes that may hinder efficient delivery of MHC class II molecules to the plasma membrane. Our data suggest that FTY720 and FTY720-P at submicromolar concentrations mediate anti-inflammatory effects on astrocytes by suppressing their action as APCs, which may further downregulate the inflammatory process in the brain, constituting the therapeutic effect of fingolimod in MS.
PLoS One. 2013 May 7;8(5):e64050. doi: 10.1371/journal.pone.0064050. Print 2013.
FTY720/fingolimod, a sphingosine analogue, reduces amyloid-β production in neurons.
Sphingosine-1-phosphate (S1P) is a pluripotent lipophilic mediator working as a ligand for G-protein coupled S1P receptors (S1PR), which is currently highlighted as a therapeutic target for autoimmune diseases including relapsing forms of multiple sclerosis. Sphingosine related compounds, FTY720 and KRP203 known as S1PR modulators, are phosphorylated by sphingosine kinase 2 (SphK2) to yield the active metabolites FTY720-P and KRP203-P, which work as functional antagonists for S1PRs.
Here we report that FTY720 and KRP203 decreased production of Amyloid-β peptide (Aβ), a pathogenic proteins causative for Alzheimer disease (AD), in cultured neuronal cells. Pharmacological analyses suggested that the mechanism of FTY720-mediated Aβ decrease in cells was independent of known downstream signaling pathways of S1PRs. Unexpectedly, 6-days treatment of APP transgenic mice with FTY720 resulted in a decrease in Aβ40, but an increase in Aβ42 levels in brains. These results suggest that S1PR modulators are novel type of regulators for Aβ metabolisms that are active in vitro and in vivo.
Biol Pharm Bull. 2011;34(6):933-6.
Relapse of experimental autoimmune encephalomyelitis after discontinuation of FTY720 (Fingolimod) treatment, but not after combination of FTY720 and pathogenic autoantigen.
FTY720 (Fingolimod) is known to have a significant therapeutic effect on experimental autoimmune encephalomyelitis (EAE). Here, we used an EAE mouse model, which had been established by immunizing C57BL/6J mice with a partial peptide of myelin oligodendrocyte glycoprotein (MOG₃₅₋₅₅), to examine the relapse of EAE upon discontinuation of treatment with FTY720 alone or in combination with MOG₃₅₋₅₅. Relapse was confirmed to occur in all animals (n=6) within one week after discontinuation of FTY720, with increase in the number of lymphocytes infiltrating the spinal cord and demyelination. However, in the case of combination therapy with FTY720 and MOG₃₅₋₅₅, relapse following discontinuation of treatment was completely suppressed. The autoantigenic peptide might serve to suppress the clonal selection of relapse-associated autoantigen-specific T cells.