Blackcurrant proanthocyanidins augment IFN-gamma-induced suppression of IL-4 stimulated CCL26 secretion in alveolar epithelial cells.
Epidemiological studies reveal that fruit consumption reduces the prevalence of airway inflammation and childhood asthma. In particular, blackcurrant polyphenolic extracts have been shown to alleviate lung inflammation. Since IL-4-stimulated eotaxin-3 (CCL26) secretion is a major factor in the continuous eosinophil recruitment observed in atopic asthma, our focus was to evaluate the effectiveness of blackcurrant polyphenolic compounds on CCL26 secretion in human alveolar epithelial cells. Our results indicate that a proanthocyanin-enriched blackcurrant extract (BC-P), but not anthocyanin-enriched blackcurrant extract suppressed both IL-4- and IL-13-stimulated CCL26 secretion in a dose-dependent manner. Furthermore pre-incubation of cells with BC-P caused a time-dependent suppression of IL-4-stimulated CCL26 secretion. Moreover, epigallocatechin (EGC), and to a lesser extent epicatechin, metabolites identified in the proanthocyanidin extract, suppressed IL-4-stimulated CCL26 secretion. EGC was also effective at reducing the cellular phosphorylated STAT-6/STAT-6 ratio. Furthermore, both BC-P and purified EGC potentiated the ability of IFN-gamma to suppress IL-4-stimulated CCL26 secretion. The progression of an allergic immune response is complex, identifying plant compounds that target specific cellular events and complement the body's own immune actions is important for the development of functional foods. Our findings support the potential for blackcurrant polyphenolic compounds to reduce eosinophil recruitment and alleviate eosinophilic-driven airway inflammation.
Food Innovation portfolio, The Plant and Food Research Institute of New Zealand Ltd., Palmerston North, New Zealand. roger.hurst@plantandfood.co.nz
Suzanne M
SM
Hurst
Tony K
TK
McGhie
Janine M
JM
Cooney
Dwayne J
DJ
Jensen
Elaine M
EM
Gould
Kirsty A
KA
Lyall
Roger D
RD
Hurst
D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000032:analysis / Q000737:chemistry / Q000494:pharmacology; D001249:Asthma / Q000517:prevention & control; D002392:Catechin / Q000031:analogs & derivatives / Q000494:pharmacology; D002460:Cell Line; D000075906:Chemokine CCL26; D019742:Chemokines, CC / Q000235:genetics / Q000378:metabolism*; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D005638:Fruit / Q000737:chemistry; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007371:Interferon-gamma / Q000819:agonists / Q000494:pharmacology*; D018793:Interleukin-13 / Q000037:antagonists & inhibitors / Q000494:pharmacology; D015847:Interleukin-4 / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D009994:Osmolar Concentration; D010766:Phosphorylation / Q000187:drug effects; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D044945:Proanthocyanidins / Q000032:analysis / Q000737:chemistry / Q000494:pharmacology*; D011650:Pulmonary Alveoli / Q000187:drug effects* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology; D031965:Ribes / Q000737:chemistry*; D050800:STAT6 Transcription Factor / Q000378:metabolism; D013997:Time Factors
D000894:Anti-Inflammatory Agents, Non-Steroidal; C120429:CCL26 protein, human; D000075906:Chemokine CCL26; D019742:Chemokines, CC; C508598:IL4 protein, human; D018793:Interleukin-13; D010936:Plant Extracts; D044945:Proanthocyanidins; D012333:RNA, Messenger; D011994:Recombinant Proteins; D050800:STAT6 Transcription Factor; C494101:STAT6 protein, human; D015847:Interleukin-4; D007371:Interferon-gamma; D002392:Catechin; C057580:gallocatechol