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Hyperosmotic stress activates the expression of members of the miR-15/107 family and induces downregulation of anti-apoptotic genes in rat liver.

Santosa D, Castoldi M, Paluschinski M, Sommerfeld A, Häussinger D - Sci Rep (2015)

Bottom Line: It was also identified that hyperosmolarity significantly reduces the expression of anti-apoptotic genes including Bcl2, Ccnd1, Mcl1, Faim, Aatf, Bfar and Ikbkb, which are either validated or predicted targets of these microRNAs.Moreover, through the application of NOX and JNK inhibitors as well as benzylamine it is shown that the observed response is mediated by reactive oxygen species (ROS), suggesting that miR-15a, miR-15b and miR-16 are novel redoximiRs.It is concluded that the response of these three microRNAs to osmotic stress is ROS-mediated and that it might contribute to the development of a proapoptotic phenotype.

View Article: PubMed Central - PubMed

Affiliation: Department of Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Moorenstrasse 5, 40225 Düsseldorf, Germany.

ABSTRACT
microRNAs are an abundant class of small non-coding RNAs that negatively regulate gene expression. Importantly, microRNA activity has been linked to the control of cellular stress response. In the present study, we investigated whether the expression of hepatic microRNAs is affected by changes in ambient osmolarity. It is shown that hyperosmotic exposure of perfused rat liver induces a rapid upregulation of miR-15a, miR-15b and miR-16, which are members of the miR-15/107 microRNAs superfamily. It was also identified that hyperosmolarity significantly reduces the expression of anti-apoptotic genes including Bcl2, Ccnd1, Mcl1, Faim, Aatf, Bfar and Ikbkb, which are either validated or predicted targets of these microRNAs. Moreover, through the application of NOX and JNK inhibitors as well as benzylamine it is shown that the observed response is mediated by reactive oxygen species (ROS), suggesting that miR-15a, miR-15b and miR-16 are novel redoximiRs. It is concluded that the response of these three microRNAs to osmotic stress is ROS-mediated and that it might contribute to the development of a proapoptotic phenotype.

No MeSH data available.


Related in: MedlinePlus

Transcription factors Egr1 and Foxo3 are osmoregulated genes.The transcription factors Egr1 and Foxo3 are significantly upregulated after 180 minutes of hyperosmotic stimulation. Statistical analysis was carried out by unpaired student’s t-test. Data are shown as average ± S.E.M. of 4 independent experiments. qPCR runs were normalized according to the ΔΔCt method using β-Tubulin as reference gene. The values of unstimulated controls were set arbitrarily to 100.
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f11: Transcription factors Egr1 and Foxo3 are osmoregulated genes.The transcription factors Egr1 and Foxo3 are significantly upregulated after 180 minutes of hyperosmotic stimulation. Statistical analysis was carried out by unpaired student’s t-test. Data are shown as average ± S.E.M. of 4 independent experiments. qPCR runs were normalized according to the ΔΔCt method using β-Tubulin as reference gene. The values of unstimulated controls were set arbitrarily to 100.

Mentions: To gain an insight into the signaling pathways potentially regulated by hyperosmolarity in perfused rat liver, Gene Ontology (GO) enrichment was carried out for the list of up- and downregulated genes at 180 minutes (Supplementary Figure 4). Interestingly, GO Term enrichment analysis identified several highly enriched pathways, which are associated to ‘cell death’ (GO:0043067, p = 2.03 × 10−9; GO:0010941, p = 6.81 × 10−9 and GO:0012501,  = 1.83 × 10−7) and ‘apoptosis’ (GO:0042981, p = 1.13 × 10−9; GO:0043065, p = 1.3 × 10−6 and GO:0043066, p = 4.26 × 10−6; Supplementary Figure 4a). Whereas, among the upregulated genes the ‘regulation of transcription from RNA polymerase II promoter’ (GO:0006357, p = 5.08 × 10−14; Supplementary Figure 4b) was the pathway with the highest enrichment, suggesting that hyperosmotic treatment could potentially affect the expression of factors controlling transcription. Importantly, correlation among the 57 genes included in this GO term with literature mining suggests that the transcription factors Foxo3 and Egr1 are potential candidates for mediating the transcriptional regulation of miR-15a, -15b and -163940. Notably, Foxo3 was shown to upregulate miR-30d in renal carcinoma, thereby inducing cell cycle arrest and apoptosis41. Egr1 was shown to be upregulated by H2O2, and to play a crucial role in the transcriptional regulation of miR-20b in breast cancer42. Importantly, microarray data validation by qPCR confirmed the significant upregulation of both, Egr1 (2.6-folds; p = 0.008) and Foxo3 (4.4-folds; p = 0.003) after 180 minutes of hyperosmotic perfusion when compared to the normoosmotic control (Fig. 11). Further studies are required to substantiate the link between hyperosmotic Egr1/Foxo3 regulation and miR-15/16 expression.


Hyperosmotic stress activates the expression of members of the miR-15/107 family and induces downregulation of anti-apoptotic genes in rat liver.

Santosa D, Castoldi M, Paluschinski M, Sommerfeld A, Häussinger D - Sci Rep (2015)

Transcription factors Egr1 and Foxo3 are osmoregulated genes.The transcription factors Egr1 and Foxo3 are significantly upregulated after 180 minutes of hyperosmotic stimulation. Statistical analysis was carried out by unpaired student’s t-test. Data are shown as average ± S.E.M. of 4 independent experiments. qPCR runs were normalized according to the ΔΔCt method using β-Tubulin as reference gene. The values of unstimulated controls were set arbitrarily to 100.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4508667&req=5

f11: Transcription factors Egr1 and Foxo3 are osmoregulated genes.The transcription factors Egr1 and Foxo3 are significantly upregulated after 180 minutes of hyperosmotic stimulation. Statistical analysis was carried out by unpaired student’s t-test. Data are shown as average ± S.E.M. of 4 independent experiments. qPCR runs were normalized according to the ΔΔCt method using β-Tubulin as reference gene. The values of unstimulated controls were set arbitrarily to 100.
Mentions: To gain an insight into the signaling pathways potentially regulated by hyperosmolarity in perfused rat liver, Gene Ontology (GO) enrichment was carried out for the list of up- and downregulated genes at 180 minutes (Supplementary Figure 4). Interestingly, GO Term enrichment analysis identified several highly enriched pathways, which are associated to ‘cell death’ (GO:0043067, p = 2.03 × 10−9; GO:0010941, p = 6.81 × 10−9 and GO:0012501,  = 1.83 × 10−7) and ‘apoptosis’ (GO:0042981, p = 1.13 × 10−9; GO:0043065, p = 1.3 × 10−6 and GO:0043066, p = 4.26 × 10−6; Supplementary Figure 4a). Whereas, among the upregulated genes the ‘regulation of transcription from RNA polymerase II promoter’ (GO:0006357, p = 5.08 × 10−14; Supplementary Figure 4b) was the pathway with the highest enrichment, suggesting that hyperosmotic treatment could potentially affect the expression of factors controlling transcription. Importantly, correlation among the 57 genes included in this GO term with literature mining suggests that the transcription factors Foxo3 and Egr1 are potential candidates for mediating the transcriptional regulation of miR-15a, -15b and -163940. Notably, Foxo3 was shown to upregulate miR-30d in renal carcinoma, thereby inducing cell cycle arrest and apoptosis41. Egr1 was shown to be upregulated by H2O2, and to play a crucial role in the transcriptional regulation of miR-20b in breast cancer42. Importantly, microarray data validation by qPCR confirmed the significant upregulation of both, Egr1 (2.6-folds; p = 0.008) and Foxo3 (4.4-folds; p = 0.003) after 180 minutes of hyperosmotic perfusion when compared to the normoosmotic control (Fig. 11). Further studies are required to substantiate the link between hyperosmotic Egr1/Foxo3 regulation and miR-15/16 expression.

Bottom Line: It was also identified that hyperosmolarity significantly reduces the expression of anti-apoptotic genes including Bcl2, Ccnd1, Mcl1, Faim, Aatf, Bfar and Ikbkb, which are either validated or predicted targets of these microRNAs.Moreover, through the application of NOX and JNK inhibitors as well as benzylamine it is shown that the observed response is mediated by reactive oxygen species (ROS), suggesting that miR-15a, miR-15b and miR-16 are novel redoximiRs.It is concluded that the response of these three microRNAs to osmotic stress is ROS-mediated and that it might contribute to the development of a proapoptotic phenotype.

View Article: PubMed Central - PubMed

Affiliation: Department of Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Moorenstrasse 5, 40225 Düsseldorf, Germany.

ABSTRACT
microRNAs are an abundant class of small non-coding RNAs that negatively regulate gene expression. Importantly, microRNA activity has been linked to the control of cellular stress response. In the present study, we investigated whether the expression of hepatic microRNAs is affected by changes in ambient osmolarity. It is shown that hyperosmotic exposure of perfused rat liver induces a rapid upregulation of miR-15a, miR-15b and miR-16, which are members of the miR-15/107 microRNAs superfamily. It was also identified that hyperosmolarity significantly reduces the expression of anti-apoptotic genes including Bcl2, Ccnd1, Mcl1, Faim, Aatf, Bfar and Ikbkb, which are either validated or predicted targets of these microRNAs. Moreover, through the application of NOX and JNK inhibitors as well as benzylamine it is shown that the observed response is mediated by reactive oxygen species (ROS), suggesting that miR-15a, miR-15b and miR-16 are novel redoximiRs. It is concluded that the response of these three microRNAs to osmotic stress is ROS-mediated and that it might contribute to the development of a proapoptotic phenotype.

No MeSH data available.


Related in: MedlinePlus