Recent baby formula milk powder contamination incidents have shown that the classic markers or standards in milk quality control are insufficient in identifying ＂manipulated＂ poor-quality milk. In the present study, we demonstrated for the first time that cow milk contains large amounts of microRNAs （miRNAs） and that the unique expression profile of milk-specific miRNAs can serve as a novel indicator and possible new standard for the quafity control of raw milk and milk-related commercial products, such as fluid milk and powdered formula milk. First, using Solexa sequencing, we systematically screened miRNA expression in raw milk and identified a total of 245 miR- NAs in raw milk. Unlike other classic biomarkers whose expression levels are nearly identical at different periods of lactation, individual miRNAs can be significantly altered during lactation process, implicating that miRNAs may be a more accurate indicator to reflect the quality alteration of milk. Second, using TaqMan probe-based miRNA quantitative RT-PCR, we further identified seven miRNAs that have a relatively consistent expression throughout the lactation process, and more importantly, the expression profile of these seven milk-specific miRNAs can serve as an ideal biomarker for discriminating poor-quality or ＂manipulated＂ milk from pure raw milk, as well as for the quality control of commercial milk products, such as fluid milk and powdered formula milk. Together, our findings provide a basis for understanding the physiological role of milk miRNAs and a new potential standard for determining the quality of raw milk or milk-related commercial products.
Peroxisome proliferator-activated receptor gamma （PPAR）,） coactivator-1 alpha （PGC-1α） coactivates multiple transcription factors and regulates several metabolic processes. The current study investigated the role of PGC-1α in the induction of apoptosis in human epithelial ovarian cancer cells. The PGC-1α mRNA level between human ovaries and human ovarian epithelial tumors was examined by quantitative RT-PCR. Less PGC- 1α expression was found in the surface epithelium of malignant tumors compared with normal ovaries. Overexpression of PGC-1α in human epithelial ovarian cancer cell line Ho-8910 induced cell apoptosis through the coordinated regulation of Bcl-2 and Bax expression. Microarray analyses confirmed that PGC-1α dramatically affected the apoptosis-related genes in Ho-8910 cells. Mitochondrial functional assay showed that the induction of apoptosis was through the terminal stage by the release of cytochrome c. Furthermore, PG-C- 1 α-induced apoptosis was partially, but not completely, blocked by PPAR）, antagonist （GW9662）, and suppression of PPAR）, expression by siRNA also inhibited PGC-1α-induced apoptosis in Ho-8910 cells. These data suggested that PGC-1α exerted its effect through a PPARγ-dependent pathway. Our findings indicated that PGC-1α was involved in the apoptotic signal transduction pathways and downregulation of PGC-1α may be a key point in promoting epithelial ovarian cancer growth and progression.
