Matrine Inhibits CNS Autoimmunity Through an IFN-ß-Dependent Mechanism.

Matrine (MAT), a quinolizidine alkaloid component derived from the root of Sophora flavescens, suppresses experimental autoimmune encephalomyelitis (EAE), the animal model of multiple sclerosis (MS), by inducing the production of immunomodulatory molecules, e.g., IL-10. In an effort to find the upstream pathway(s) of the mechanism underlying these effects, we have tested certain upregulated immunomodulatory molecules. Among them, we found increased levels of IL-27 and IFN-ß, one of the first-line MS therapies. Indeed, while low levels of IFN-ß production in sera and type I interferon receptor (IFNAR1) expression in spinal cord of saline-treated control EAE mice were detected, they were significantly increased after MAT treatment. Increased numbers of CD11b+IFN-ß+ microglia/infiltrating macrophages were observed in the CNS of MAT-treated mice. The key role of IFN-ß induction in the suppressive effect of MAT on EAE was further verified by administration of anti-IFN-ß neutralizing antibody, which largely reversed the therapeutic effect of MAT. Further, we found that, while MAT treatment induced production of IL-27 and IL-10 by CNS microglia/macrophages, this effect was significantly reduced by IFN-ß neutralizing antibody. Finally, the role of IFN-ß in MAT-induced IL-27 and IL-10 production was further confirmed in human monocytes in vitro. Together, our study demonstrates that MAT exerts its therapeutic effect in EAE through an IFN-ß/IL-27/IL-10 pathway, and is likely a novel, safe, low-cost, and effective therapy as an alternative to exogenous IFN-ß for MS.

Matrine protects oligodendrocytes by inhibiting their apoptosis and enhancing mitochondrial autophagy.

Stressed oligodendrocytes (OLGs) activate microglia to produce an inflammatory response, and the impairment of mitochondria further aggravates OLG damage, which is the earliest pathological change in multiple sclerosis (MS), an inflammatory demyelinating disease of the central nervous system. Matrine (MAT), a tetracyclic quinolizine alkaloid derived from the herb radix sophorae flavescentis, has been shown to effectively ameliorate clinical signs of experimental autoimmune encephalomyelitis (EAE), an animal model of MS. However, the mechanisms underlying the effect of MAT treatment need to be further studied. In the present study, we show that MAT effectively suppressed ongoing EAE, and significantly reduced the expression of caspase-3 and alpha B-crystallin in OLGs, therefore lessen OLG apoptosis, microglial activation and inflammatory factors secretion. MAT treatment also reduced the content of cytochrome c and malondialdehyde, an oxidative stress marker, in the central nervous system. In contrast, the levels of autophagy-related proteins Beclin1, microtubule-associated protein l light chain 3 and glutathione peroxidase was upregulated, hence enhancing mitochondrial autophagy and alleviating the imbalance of the oxidation/antioxidation system caused by mitochondrial damage. Our research indicates that MAT is effective in treating EAE, at least in part, by protecting OLGs through inhibiting their apoptosis and enhancing mitochondrial autophagy.

Matrine promotes NT3 expression in CNS cells in experimental autoimmune encephalomyelitis.

Neurotrophin 3 (NT3) is a potent neurotrophic factor for promoting remyelination and recovery of neuronal function; upregulation of its expression in the central nervous system (CNS) is thus of major therapeutic importance for neurological deficits. Matrine (MAT), a quinolizidine alkaloid derived from the herb Radix Sophorae Flavescent, has been recently reported to effectively ameliorate clinical signs in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS), by secreting antiinflammatory cytokines. In the present study, our goal was to investigate whether MAT could affect NT3 expression of glial cells in the CNS, the major cell populations in the CNS foci of MS/EAE. We found that MAT markedly upregulated NT3 expression in the CNS not only by microglia/macrophages and astrocytes, but also by oligodendrocyte precursor cells, indicative of both paracrine and autocrine effects on myelinating cells. While MAT treatment reduced the numbers of iNOS+ M1, but increased Arg1+ M2 microglia/macrophage phenotypes, NT3 expression was upregulated in both phenotypes. These results indicate that MAT therapy for EAE acts, at least in part, by stimulating local production of NT3 by glial cells in the CNS, which protects neural cells from CNS inflammation-induced tissue damage.

Temperature-responsive, Pluronic-g-poly(acrylic acid) copolymers in situ gels for ophthalmic drug delivery: rheology, in vitro drug release, and in vivo resident property.

To prolong the precorneal resident time and improve ocular bioavailability of the drug, Pluronic-g-poly(acrylic acid) copolymers were studied as a temperature-responsive in situ gelling vehicle for an ophthalmic drug delivery system. The rheological properties and in vitro drug release of Pluronic-g-PAA copolymer gels, as well as the in vivo resident properties of such in situ gel ophthalmic formulations, were investigated. The rheogram and in vitro drug release studies indicated that the drug release rates decreased as acrylic acid/Pluronic molar ratio and copolymer solution concentration increased. It was also shown that the drug concentration had no obvious effect on drug release. The release rates of drug from such copolymer gels were mainly dependent on the gel dissolution. In vivo resident experiments showed the drug resident time and the total resident amount increased by 4-fold and 1.2-fold for in situ gel compared with eye drops. These in vivo experimental results, along with the rheological properties and in vitro drug release studies, demonstrated that in situ gels containing Pluronic-g-PAA copolymer may significantly prolong the drug resident time and thus improve bioavailability. The results showed that the Pluronic-g-PAA copolymer can be a promising in situ gelling vehicle for ophthalmic drug delivery.

Pluronic F127-g-poly(acrylic acid) copolymers as in situ gelling vehicle for ophthalmic drug delivery system.

To prolong the precorneal resident time and improve ocular bioavailability of the drug, Pluronic F127-g-poly(acrylic acid) copolymers were studied as in situ gelling vehicle for ophthalmic drug delivery system. The rheological properties and in vitro drug release of Pluronic-g-PAA copolymer gels were investigated. The rheogram and in vitro drug release studies indicated that the drug release rates decreased as acrylic acid/Pluronic molar ratio and copolymer solution concentration increased. But the drug concentration had no obvious effect on drug release. The release rates of the drug from such copolymer gels were mainly dependent on the gel dissolution. In vivo resident experiments showed the drug resident time and the total resident amount in rabbit's conjunctiveal sac increased by 5.0 and 2.6 folds for in situ gel, compared with eye drops. The decreased loss angle at body temperature and prolonged precorneal resident time also indicated that the copolymer gels had bioadhesive properties. These in vivo experimental results, along with the rheological properties and in vitro drug release studies, demonstrated that in situ gels containing Pluronic-g-PAA copolymer may significantly prolong the drug resident time and thus improve bioavailability. Pluronic-g-PAA copolymer can be a promising in situ gelling vehicle for ophthalmic drug delivery system.