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Sex-different and growth hormone-regulated expression of microRNA in rat liver.

Cheung L, Gustavsson C, Norstedt G, Tollet-Egnell P - BMC Mol. Biol. (2009)

Bottom Line: Out of 324 unique probes on the array, 254 were expressed in the liver and eight (3% of 254) of those were found to be different between the sexes.The biggest effects were obtained on miR-29b with GH-treatment.We conclude that hepatic miRNA levels depend on the hormonal and nutritional status of the animal and show that miR-29b is a female-predominant and GH-regulated miRNA in rat liver.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Molecular Medicine and Surgery, Karolinska Institutet, Centre for Molecular Medicine, L8:01, Karolinska University Hospital, 171 76 Stockholm, Sweden. louisa.y.cheung@googlemail.com

ABSTRACT

Background: MicroRNAs (miRNAs) are short non-coding RNAs playing an important role in post-transcriptional regulation of gene expression. We have previously shown that hepatic transcript profiles are different between males and females; that some of these differences are under the regulation of growth hormone (GH); and that mild starvation diminishes some of the differences. In this study, we tested if hepatic miRNAs are regulated in a similar manner.

Results: Using microarrays, miRNA screening was performed to identify sex-dependent miRNAs in rat liver. Out of 324 unique probes on the array, 254 were expressed in the liver and eight (3% of 254) of those were found to be different between the sexes. Among the eight putative sex-different miRNAs, only one female-predominant miRNA (miR-29b) was confirmed using quantitative real-time PCR. Furthermore, 1 week of continuous GH-treatment in male rats reduced the levels of miR-451 and miR-29b, whereas mild starvation (12 hours) raised the levels of miR-451, miR-122a and miR-29b in both sexes. The biggest effects were obtained on miR-29b with GH-treatment.

Conclusion: We conclude that hepatic miRNA levels depend on the hormonal and nutritional status of the animal and show that miR-29b is a female-predominant and GH-regulated miRNA in rat liver.

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Effects of mild starvation on hepatic miRNA levels. Livers from mildly starved or postabsorptive male and female rats were used to extract miRNA-enriched RNA. cDNA was synthesized from 100 ng of this miRNA-enriched RNA using miRNA specific primers (miR-29b, miR-451, miR-122a) or random hexamers (5S rRNA), and real-time PCR analysis was used to quantify RNA levels. The results were related to corresponding levels in males at four hours of food deprivation and presented as ratios (mean ± S.E.). # indicate significant differences (p < 0.05) between mildly starved (12h FD) and postabsorptive (4h FD) rats, whereas * indicate significant sex-differences (p < 0.05), using student's t-test.
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Figure 3: Effects of mild starvation on hepatic miRNA levels. Livers from mildly starved or postabsorptive male and female rats were used to extract miRNA-enriched RNA. cDNA was synthesized from 100 ng of this miRNA-enriched RNA using miRNA specific primers (miR-29b, miR-451, miR-122a) or random hexamers (5S rRNA), and real-time PCR analysis was used to quantify RNA levels. The results were related to corresponding levels in males at four hours of food deprivation and presented as ratios (mean ± S.E.). # indicate significant differences (p < 0.05) between mildly starved (12h FD) and postabsorptive (4h FD) rats, whereas * indicate significant sex-differences (p < 0.05), using student's t-test.

Mentions: We have previously compared gene expression levels from rat livers during mild starvation (12 hours of food deprivation) and the postabsorptive state (4 hours of food deprivation) [11]. The notion that sex-dependent and GH-regulated transcripts were differentially expressed between these metabolic states, we next addressed the question whether miRNA levels would also be affected. As illustrated in figure 3, the level of miR-451 was significantly up-regulated in males (7.4-fold, p < 0.001) and females (9.7-fold, p = 0.03) after mild starvation, without any sex-differences (Figure 3c). Females had a significantly higher level (7.2-fold, p = 0.03) of miR-122a expression in the postabsorptive state, whereas mild starvation up-regulated miR-122a in both sexes and diminished this sex-difference (16-fold, p < 0.001 in males and 3.2-fold, p = 0.003 in females) (Figure 3d). Similar results were obtained for miR-29b, with increased levels in both males (8.5-fold, p < 0.001) and females (3-fold, p = 0.04) (Figure 3b). The level of 5S rRNA was also increased by mild starvation, but without statistical significance (Figure 3a). We conclude that mild starvation up-regulated the levels of miR-451, miR-122a and miR-29b significantly in both sexes, when compared to the postabsorptive state.


Sex-different and growth hormone-regulated expression of microRNA in rat liver.

Cheung L, Gustavsson C, Norstedt G, Tollet-Egnell P - BMC Mol. Biol. (2009)

Effects of mild starvation on hepatic miRNA levels. Livers from mildly starved or postabsorptive male and female rats were used to extract miRNA-enriched RNA. cDNA was synthesized from 100 ng of this miRNA-enriched RNA using miRNA specific primers (miR-29b, miR-451, miR-122a) or random hexamers (5S rRNA), and real-time PCR analysis was used to quantify RNA levels. The results were related to corresponding levels in males at four hours of food deprivation and presented as ratios (mean ± S.E.). # indicate significant differences (p < 0.05) between mildly starved (12h FD) and postabsorptive (4h FD) rats, whereas * indicate significant sex-differences (p < 0.05), using student's t-test.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2654566&req=5

Figure 3: Effects of mild starvation on hepatic miRNA levels. Livers from mildly starved or postabsorptive male and female rats were used to extract miRNA-enriched RNA. cDNA was synthesized from 100 ng of this miRNA-enriched RNA using miRNA specific primers (miR-29b, miR-451, miR-122a) or random hexamers (5S rRNA), and real-time PCR analysis was used to quantify RNA levels. The results were related to corresponding levels in males at four hours of food deprivation and presented as ratios (mean ± S.E.). # indicate significant differences (p < 0.05) between mildly starved (12h FD) and postabsorptive (4h FD) rats, whereas * indicate significant sex-differences (p < 0.05), using student's t-test.
Mentions: We have previously compared gene expression levels from rat livers during mild starvation (12 hours of food deprivation) and the postabsorptive state (4 hours of food deprivation) [11]. The notion that sex-dependent and GH-regulated transcripts were differentially expressed between these metabolic states, we next addressed the question whether miRNA levels would also be affected. As illustrated in figure 3, the level of miR-451 was significantly up-regulated in males (7.4-fold, p < 0.001) and females (9.7-fold, p = 0.03) after mild starvation, without any sex-differences (Figure 3c). Females had a significantly higher level (7.2-fold, p = 0.03) of miR-122a expression in the postabsorptive state, whereas mild starvation up-regulated miR-122a in both sexes and diminished this sex-difference (16-fold, p < 0.001 in males and 3.2-fold, p = 0.003 in females) (Figure 3d). Similar results were obtained for miR-29b, with increased levels in both males (8.5-fold, p < 0.001) and females (3-fold, p = 0.04) (Figure 3b). The level of 5S rRNA was also increased by mild starvation, but without statistical significance (Figure 3a). We conclude that mild starvation up-regulated the levels of miR-451, miR-122a and miR-29b significantly in both sexes, when compared to the postabsorptive state.

Bottom Line: Out of 324 unique probes on the array, 254 were expressed in the liver and eight (3% of 254) of those were found to be different between the sexes.The biggest effects were obtained on miR-29b with GH-treatment.We conclude that hepatic miRNA levels depend on the hormonal and nutritional status of the animal and show that miR-29b is a female-predominant and GH-regulated miRNA in rat liver.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Molecular Medicine and Surgery, Karolinska Institutet, Centre for Molecular Medicine, L8:01, Karolinska University Hospital, 171 76 Stockholm, Sweden. louisa.y.cheung@googlemail.com

ABSTRACT

Background: MicroRNAs (miRNAs) are short non-coding RNAs playing an important role in post-transcriptional regulation of gene expression. We have previously shown that hepatic transcript profiles are different between males and females; that some of these differences are under the regulation of growth hormone (GH); and that mild starvation diminishes some of the differences. In this study, we tested if hepatic miRNAs are regulated in a similar manner.

Results: Using microarrays, miRNA screening was performed to identify sex-dependent miRNAs in rat liver. Out of 324 unique probes on the array, 254 were expressed in the liver and eight (3% of 254) of those were found to be different between the sexes. Among the eight putative sex-different miRNAs, only one female-predominant miRNA (miR-29b) was confirmed using quantitative real-time PCR. Furthermore, 1 week of continuous GH-treatment in male rats reduced the levels of miR-451 and miR-29b, whereas mild starvation (12 hours) raised the levels of miR-451, miR-122a and miR-29b in both sexes. The biggest effects were obtained on miR-29b with GH-treatment.

Conclusion: We conclude that hepatic miRNA levels depend on the hormonal and nutritional status of the animal and show that miR-29b is a female-predominant and GH-regulated miRNA in rat liver.

Show MeSH