Apigenin, a natural flavonoid, found in several plants, fruits, vegetables, herbs, and spices, is known to have anti-oxidant and anti-inflammatory properties that are evident in the use of these substances for centuries as medicinal approaches to treat asthma, insomnia, Parkinson's disease, neuralgia, and shingles. However, there is a considerable dearth of information regarding its effect on immune cells, especially dendritic cells (DC) that maintain the critical balance between an immunogenic and tolerogenic immune response, in an immunospecialized location like the central nervous system (CNS). In this paper we looked at the anti-inflammatory properties of Apigenin in restoration of immune function and the resultant decrease in neuroinflammation. In vivo, a significant reduction in severity of experimental autoimmune encephalomyelitis (EAE) progression and relapse was observed in C57BL/6 (progressive) and SJL/J (relapse-remitting) mouse models of multiple sclerosis upon treatment with Apigenin. Apigenin treated EAE mice show decreased expression of α4 integrin and CLEC12A on splenic DCs and an increased retention of immune cells in the periphery compared to untreated EAE mice. This correlated consequently with immunohistochemistry findings of decreased immune cell infiltration and reduced demyelination in the CNS. These results indicate a protective role of Apigenin against the neurodegenerative effects resulting from the entry of DC stimulated pathogenic T cells into the CNS thus implicating a potential therapy for neuroinflammatory disease.

Canine bestrophinopathy (cBest) is an important translational model for BEST1-associated maculopathies in man that recapitulates the broad spectrum of clinical and molecular disease aspects observed in patients. Both human and canine bestrophinopathies are characterized by focal to multifocal separations of the retina from the RPE. The lesions can be macular or extramacular, and the specific pathomechanism leading to formation of these lesions remains unclear. We used the naturally occurring canine BEST1 model to examine factors that underlie formation of vitelliform lesions and addressed the susceptibility of the macula to its primary detachment in BEST1-linked maculopathies.

Apigenin, a natural flavonoid, found in several plants is known to have anti-oxidant and anti-inflammatory properties indicated by its use for centuries as a medicinal approach to treat inflammatory disorders. However, there are significant gaps in knowledge regarding its effect on dendritic cell (DC) function in maintaining an immune balance in immunospecialized locations like the central nervous system (CNS). In order to establish the potential utility of Apigenin as a therapeutic agent against neuroinflammatory diseases, we tested and found that Apigenin treatment ameliorated severity of disease progression and relapse after onset of experimental autoimmune encephalomyelitis (EAE) in C57BL/6 and SJL mouse models of multiple sclerosis. An increased retention of DCs and other myeloid cells in the periphery correlated with decreased immune cell infiltration and reduced demyelination in the CNS in treated mice. Mechanistically, Apigenin treatment reduced RelB expression in presence of LPS in human peripheral blood DCs, which is central to DC maturation, its antigen presentation capabilities and DC-mediated T cell activation. IL-12A and IL-23, downstream pro-inflammatory targets of RelB were reduced upon Apigenin treatment in these cells. Further, RelB causes a metabolic switch in immune cells upon inflammation, which was seen as a decrease in glucose uptake and lactate production (glycolysis), and an increase in mitochondrial activity when LPS-induced DCs were treated with Apigenin. These results indicate a protective role of Apigenin against DC-regulated neurodegenerative effects through a probable RelB mediated pathway thus implicating a potential therapy for neuroinflammatory disease.

Apigenin, a natural flavonoid, found in several plants is known to have anti-oxidant and anti-inflammatory properties indicated by its use for centuries as a medicinal approach to treat inflammatory disorders. However, there are significant gaps in knowledge regarding its effect on dendritic cell (DC) function in maintaining an immune balance in immunospecialized locations like the central nervous system (CNS). In order to establish the potential utility of Apigenin as a therapeutic agent against neuroinflammatory diseases, we tested and found that Apigenin treatment ameliorated severity of disease progression and relapse after onset of experimental autoimmune encephalomyelitis (EAE) in C57BL/6 and SJL mouse models of multiple sclerosis. An increased retention of DCs and other myeloid cells in the periphery correlated with decreased immune cell infiltration and reduced demyelination in the CNS in treated mice. Mechanistically, Apigenin treatment reduced RelB expression in presence of LPS in human peripheral blood DCs, which is central to DC maturation, its antigen presentation capabilities and DC-mediated T cell activation. IL-12A and IL-23, downstream pro-inflammatory targets of RelB were reduced upon Apigenin treatment in these cells. Further, RelB causes a metabolic switch in immune cells upon inflammation, which was seen as a decrease in glucose uptake and lactate production (glycolysis), and an increase in mitochondrial activity when LPS-induced DCs were treated with Apigenin. These results indicate a protective role of Apigenin against DC-regulated neurodegenerative effects through a probable RelB mediated pathway thus implicating a potential therapy for neuroinflammatory disease. Supported by grants from NIH: 1R01NS0971-47

The use of Apigenin, a naturally occurring plant flavone, for centuries to treat asthma, Parkinson's disease, neuralgia, and shingles, indicates its importance in the regulation of inflammation. However, its effect on dendritic cells (DC) that maintain the critical balance between an immunogenic and tolerogenic immune response especially in neuroinflammation is relatively unknown. To test if Apigenin treatment ameliorates disease after onset of experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis, C57BL/6 mice immunized with MOG35-55 were treated with Apigenin. A significant reduction in severity of EAE progression was observed in the treated mice with disease peak lasting only a day. Splenocytes isolated from Apigenin treated EAE mice show decreased expression of α4 integrin and increased DCs and macrophages compared to untreated EAE mice. This correlated with immunohistochemistry findings of decreased immune cell infiltration and reduced demyelination in the CNS. In vitro, Apigenin inhibited TNF-α and IL-6 secretion in mice splenic DCs stimulated with LPS and the cell surface expression of MHC II and CD86 molecules on bone marrow derived DCs. These results indicate a protective role of Apigenin against the neurodegenerative effects resulting from the entry of DC stimulated pathogenic T cells into the CNS. Apigenin can thus serve as a potential therapy for neuroinflammatory disease through its regulation of immunogenic T cell response.