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Mice lacking microRNAs in Pax8-expressing cells develop hypothyroidism and end-stage renal failure.

Bartram MP, Amendola E, Benzing T, Schermer B, de Vita G, Müller RU - BMC Mol. Biol. (2016)

Bottom Line: The Dgcr8/Drosha complex processes pri-miRNAs in the nucleus before they are exported as pre-miRNAs for further maturation by Dicer in the cytoplasm.Pax8Cre-mediated conditional loss of DiGeorge syndrome critical region 8 (Dgcr8), an essential component of the nuclear machinery that is required for microRNA biogenesis, resulted in severe hypothyroidism, massively reduced body weight and ultimately led to renal failure and death of the animals.These data provide further insight into the importance of miRNAs in organ homeostasis using a Dicer independent model.

View Article: PubMed Central - PubMed

Affiliation: Department II of Internal Medicine and Center for Molecular Medicine, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany.

ABSTRACT

Background: Non-coding RNAs have gained increasing attention during the last decade. The first large group of non-coding RNAs to be characterized systematically starting at the beginning of the 21st century were small oligonucleotides--the so-called microRNAs (miRNAs). By now we have learnt that microRNAs are indispensable for most biological processes including organogenesis and maintenance of organ structure and function. The role of microRNAs has been studied extensively in the development of a number of organs, so far most studies focussed on e.g. the heart or the brain whilst the role of microRNAs in the development and maintenance of complex epithelial organs is less well understood. Furthermore most analyses regarding microRNA function in epithelial organs employed conditional knockout mouse models of the RNAse III Dicer to abrogate microRNA biogenesis. However, there is increasing evidence for Dicer to have multiple functions independent from microRNA maturation. Therefore Dicer independent models are needed to gain further insight into the complex biology of miRNA dependent processes.

Results: Here we analyze the contribution of microRNA-dependent transcriptional control in Pax8-expressing epithelial cells. Pax8 is a transcription factor that is crucial to the development of epithelial organs. The miRNA machinery was disrupted by crossing conditional DiGeorge syndrome critical region 8 (Dgcr8) fl/fl mice to Pax8Cre mice. The Dgcr8/Drosha complex processes pri-miRNAs in the nucleus before they are exported as pre-miRNAs for further maturation by Dicer in the cytoplasm. Dgcr8 fl/fl; Pax8Cre+ knockout mice died prematurely, developed massive hypothyroidism and end stage renal disease due to a loss of miRNAs in Pax8 expressing tissue.

Conclusion: Pax8Cre-mediated conditional loss of DiGeorge syndrome critical region 8 (Dgcr8), an essential component of the nuclear machinery that is required for microRNA biogenesis, resulted in severe hypothyroidism, massively reduced body weight and ultimately led to renal failure and death of the animals. These data provide further insight into the importance of miRNAs in organ homeostasis using a Dicer independent model.

No MeSH data available.


Related in: MedlinePlus

Dgcr8–Pax8Cre knockout kidneys show increased proliferation and apoptosis. a TUNEL staining reveals a massive upregulation of apoptosis in kidneys of Dgcr8 knockout mice (upper panel bar 200 µm; lower panel bar 50 µm, age of the mice 4–8 weeks). b and c An increase in proliferation is detectable especially in the cortex of Dgcr8 knockout kidneys (bbar 2 mm; cbar 100 µm)
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Fig6: Dgcr8–Pax8Cre knockout kidneys show increased proliferation and apoptosis. a TUNEL staining reveals a massive upregulation of apoptosis in kidneys of Dgcr8 knockout mice (upper panel bar 200 µm; lower panel bar 50 µm, age of the mice 4–8 weeks). b and c An increase in proliferation is detectable especially in the cortex of Dgcr8 knockout kidneys (bbar 2 mm; cbar 100 µm)

Mentions: To further elucidate the consequences of loss of Dgcr8 to cellular biology in the kidney, we performed TUNEL assays. These stainings revealed a massive induction of apoptosis in all segments of the kidney (Fig. 6 a), suggesting that Dgcr8 dependent miRNAs are essential for the development and maintenance of a functional kidney tubulus system. Interestingly staining for the proliferation marker Ki-67 showed that beside apoptosis proliferation is also increased in the tubulus system, especially in the cortical region of Dgcr8 knockout mice pointing towards a general increase in cellular turnover (Fig. 6 b, c). Staining of thyroid gland tissue revealed that this increase of apoptosis (determined by TUNEL assays) on the one hand and proliferation (Ki-67 staining) on the other hand is not limited to the kidney but a general finding in the affected epithelial tissue of Dgcr8-Pax8Cre knockout mice (Additional file 3: Figure S3).Fig. 6


Mice lacking microRNAs in Pax8-expressing cells develop hypothyroidism and end-stage renal failure.

Bartram MP, Amendola E, Benzing T, Schermer B, de Vita G, Müller RU - BMC Mol. Biol. (2016)

Dgcr8–Pax8Cre knockout kidneys show increased proliferation and apoptosis. a TUNEL staining reveals a massive upregulation of apoptosis in kidneys of Dgcr8 knockout mice (upper panel bar 200 µm; lower panel bar 50 µm, age of the mice 4–8 weeks). b and c An increase in proliferation is detectable especially in the cortex of Dgcr8 knockout kidneys (bbar 2 mm; cbar 100 µm)
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4835897&req=5

Fig6: Dgcr8–Pax8Cre knockout kidneys show increased proliferation and apoptosis. a TUNEL staining reveals a massive upregulation of apoptosis in kidneys of Dgcr8 knockout mice (upper panel bar 200 µm; lower panel bar 50 µm, age of the mice 4–8 weeks). b and c An increase in proliferation is detectable especially in the cortex of Dgcr8 knockout kidneys (bbar 2 mm; cbar 100 µm)
Mentions: To further elucidate the consequences of loss of Dgcr8 to cellular biology in the kidney, we performed TUNEL assays. These stainings revealed a massive induction of apoptosis in all segments of the kidney (Fig. 6 a), suggesting that Dgcr8 dependent miRNAs are essential for the development and maintenance of a functional kidney tubulus system. Interestingly staining for the proliferation marker Ki-67 showed that beside apoptosis proliferation is also increased in the tubulus system, especially in the cortical region of Dgcr8 knockout mice pointing towards a general increase in cellular turnover (Fig. 6 b, c). Staining of thyroid gland tissue revealed that this increase of apoptosis (determined by TUNEL assays) on the one hand and proliferation (Ki-67 staining) on the other hand is not limited to the kidney but a general finding in the affected epithelial tissue of Dgcr8-Pax8Cre knockout mice (Additional file 3: Figure S3).Fig. 6

Bottom Line: The Dgcr8/Drosha complex processes pri-miRNAs in the nucleus before they are exported as pre-miRNAs for further maturation by Dicer in the cytoplasm.Pax8Cre-mediated conditional loss of DiGeorge syndrome critical region 8 (Dgcr8), an essential component of the nuclear machinery that is required for microRNA biogenesis, resulted in severe hypothyroidism, massively reduced body weight and ultimately led to renal failure and death of the animals.These data provide further insight into the importance of miRNAs in organ homeostasis using a Dicer independent model.

View Article: PubMed Central - PubMed

Affiliation: Department II of Internal Medicine and Center for Molecular Medicine, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany.

ABSTRACT

Background: Non-coding RNAs have gained increasing attention during the last decade. The first large group of non-coding RNAs to be characterized systematically starting at the beginning of the 21st century were small oligonucleotides--the so-called microRNAs (miRNAs). By now we have learnt that microRNAs are indispensable for most biological processes including organogenesis and maintenance of organ structure and function. The role of microRNAs has been studied extensively in the development of a number of organs, so far most studies focussed on e.g. the heart or the brain whilst the role of microRNAs in the development and maintenance of complex epithelial organs is less well understood. Furthermore most analyses regarding microRNA function in epithelial organs employed conditional knockout mouse models of the RNAse III Dicer to abrogate microRNA biogenesis. However, there is increasing evidence for Dicer to have multiple functions independent from microRNA maturation. Therefore Dicer independent models are needed to gain further insight into the complex biology of miRNA dependent processes.

Results: Here we analyze the contribution of microRNA-dependent transcriptional control in Pax8-expressing epithelial cells. Pax8 is a transcription factor that is crucial to the development of epithelial organs. The miRNA machinery was disrupted by crossing conditional DiGeorge syndrome critical region 8 (Dgcr8) fl/fl mice to Pax8Cre mice. The Dgcr8/Drosha complex processes pri-miRNAs in the nucleus before they are exported as pre-miRNAs for further maturation by Dicer in the cytoplasm. Dgcr8 fl/fl; Pax8Cre+ knockout mice died prematurely, developed massive hypothyroidism and end stage renal disease due to a loss of miRNAs in Pax8 expressing tissue.

Conclusion: Pax8Cre-mediated conditional loss of DiGeorge syndrome critical region 8 (Dgcr8), an essential component of the nuclear machinery that is required for microRNA biogenesis, resulted in severe hypothyroidism, massively reduced body weight and ultimately led to renal failure and death of the animals. These data provide further insight into the importance of miRNAs in organ homeostasis using a Dicer independent model.

No MeSH data available.


Related in: MedlinePlus