近日，刊登在Proceedings of the National Academy of Sciences上的一篇研究報道中，來自昆士蘭大學的研究人員通過研究揭開了母乳喂養對新生兒必不可少的原因。
文章中，研究人員通過研究解釋了孕婦機體的鈣質向母乳中轉移的分子機製，而該研究對癌症療法的開發或許具有一定的指示意義；研究者Davis教授表示，利用對齧齒類動物模型進行研究，我們發現母乳中至少有50%的鈣離子來自於一種名為Orai1的特殊蛋白。
Orai1蛋白是排乳的主要調節子，其對於年輕哺乳動物的生存非常關鍵，理解哺乳動物乳腺生物學及哺乳過程或可幫助研究人員發現關鍵的疾病發生過程，從而對於理解某些乳腺癌的發生將至關重要。
最後研究者說道，蛋白質Orai1對於哺乳動物機體鈣質的儲存非常關鍵，後期我們還將進行更為深入的研究來闡明該蛋白如何影響哺乳動物哺乳以及揭示母乳喂養對於嬰兒後期健康的重要性，同時也為理解某些乳腺癌的發病機製提供了一定的線索和幫助。
doi:10.1073/PNAS.1502264112
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Essential role of Orai1 store-operated calcium channels in lactation
Felicity M. Davisa,1, Agnes Janoshazia, Kyathanahalli S. Janardhanb, Natacha Steinckwicha, Diane M. D’Agostina, John G. Petrankaa, Pooja N. Desaia, Sarah J. Roberts-Thomsonc, Gary S. Birda, Deirdre K. Tuckerd, Suzanne E. Fentond, Stefan Feskee, Gregory R. Monteithc, and James W. Putney, Jr.a,2
The nourishment of neonates by nursing is the defining characteristic of mammals. However, despite considerable research into the neural control of lactation, an understanding of the signaling mechanisms underlying the production and expulsion of milk by mammary epithelial cells during lactation remains largely unknown. Here we demonstrate that a store-operated Ca2+ channel subunit, Orai1, is required for both optimal Ca2+ transport into milk and for milk ejection. Using a novel, 3D imaging strategy, we visualized live oxytocin-induced alveolar unit contractions in the mammary gland, and we demonstrated that in this model milk is ejected by way of pulsatile contractions of these alveolar units. In mammary glands of Orai1 knockout mice, these contractions are infrequent and poorly coordinated. We reveal that oxytocin also induces a large transient release of stored Ca2+ in mammary myoepithelial cells followed by slow, irregular Ca2+ oscillations. These oscillations, and not the initial Ca2+ transient, are mediated exclusively by Orai1 and are absolutely required for milk ejection and pup survival, an observation that redefines the signaling processes responsible for milk ejection. These findings clearly demonstrate that Ca2+ is not just a substrate for nutritional enrichment in mammals but is also a master regulator of the spatiotemporal signaling events underpinning mammary alveolar unit contraction. Orai1-dependent Ca2+ oscillations may represent a conserved language in myoepithelial cells of other secretory epithelia, such as sweat glands, potentially shedding light on other Orai1 channelopathies, including anhidrosis (an inability to sweat).
