In-vivo regulation of Krüppel-like factor 9 by corticosteroids and their receptors across tissues in tadpoles of Xenopus tropicalis

Shewade, Leena; Schneider, Katelin A.; Brown, Audrey C.; Buchholz, Daniel R.

doi:10.1016/j.ygcen.2017.02.007

“…2 B). Both klf9 and per1a are involved in circadian regulation, and both have been shown to be GR targets in other vertebrate models 16 , 35 – 37 . Interestingly, klf9 was also found to be the most commonly upregulated transcription factor gene in a recent meta-analysis of glucocorticoid-induced gene expression in the mammalian brain 38 .…”

Section: Discussionmentioning

confidence: 99%

“…Using this mutant line, we performed an RNA-seq experiment to identify genes regulated by the GR and to parse GR-dependent and GR-independent effects of chronic cortisol treatment on larval gene expression. We found that most of the transcriptomic effects of the chronic cortisol treatment are mediated by the GR and identified klf9 , which encodes a ubiquitously expressed 16 member of the krüppel-like family of zinc finger transcription factors, as the one regulatory gene consistently upregulated by the GR under both normal conditions and in response to chronic cortisol treatment. We therefore used CRISPR-Cas9 to mutate klf9 and RNA-seq to interrogate its role with respect to the transcriptomic response to chronic cortisol treatment.…”

Section: Introductionmentioning

confidence: 97%

Klf9 is a key feedforward regulator of the transcriptomic response to glucocorticoid receptor activity

Gans

¹

,

Hartig

²

,

Zhu

³

et al. 2020

Sci Rep

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The zebrafish has recently emerged as a model system for investigating the developmental roles of glucocorticoid signaling and the mechanisms underlying glucocorticoid-induced developmental programming. To assess the role of the Glucocorticoid Receptor (GR) in such programming, we used CRISPR-Cas9 to produce a new frameshift mutation, GR 369-, which eliminates all potential in-frame initiation codons upstream of the DNA binding domain. Using RNA-seq to ask how this mutation affects the larval transcriptome under both normal conditions and with chronic cortisol treatment, we find that GR mediates most of the effects of the treatment, and paradoxically, that the transcriptome of cortisol-treated larvae is more like that of larvae lacking a GR than that of larvae with a GR, suggesting that the cortisol-treated larvae develop GR resistance. The one transcriptional regulator that was both underexpressed in GR 369larvae and consistently overexpressed in cortisol-treated larvae was klf9. We therefore used CRISPR-Cas9-mediated mutation of klf9 and RNA-seq to assess Klf9-dependent gene expression in both normal and cortisol-treated larvae. Our results indicate that Klf9 contributes significantly to the transcriptomic response to chronic cortisol exposure, mediating the upregulation of proinflammatory genes that we reported previously. The vertebrate hypothalamus-pituitary-adrenal (HPA) axis orchestrates physiological, behavioral, and metabolic adjustments required for homeostasis, by dynamically regulating production and secretion of adrenal steroids known as glucocorticoids. In humans the primary glucocorticoid is cortisol, the biological activity of which is mediated by two regulatory proteins in the nuclear receptor family, the ubiquitous glucocorticoid receptor (GR) and the more tissue-restricted mineralocorticoid receptor (MR). The GR binds cortisol less avidly than the MR and is thus more dynamically regulated over the normal physiological range of cortisol fluctuations 1,2. The GR and MR function both as transcription factors and as non-nuclear signaling proteins, including in the central nervous system where both proteins are highly expressed 1-5. Given that the GR is more widely expressed and more dynamically regulated by cortisol, it is generally thought to be the principal mediator of cortisolinduced genomic responses to circadian rhythms and acute stress 5. An important question for understanding GR function is what downstream transcriptional regulatory genes does it regulate, and to what end? Answering this question is not only important for understanding the physiological function and regulation of the GR, but also for deciphering the gene regulatory networks that orchestrate adaptive developmental programming in response to chronic glucocorticoid exposure such as occurs with chronic early life stress 6. The zebrafish has recently emerged as a model system well-suited to investigating the developmental functions of glucocorticoid signaling and mechanisms underlying stress-induced developmental programming 7-...

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“…Of ~ 20,000 scored peaks, that with the 3 rd highest score encompassed the promoter of klf9 ( Fig. 2a; Table 1), a known GR target gene that functions as a feedforward regulator of GR signaling [22][23][24][25][26]. Several additional genes with high peak scores are also known GR targets in mammals, including fkbp5 ( Fig.…”

Section: Adults Derived From Cortisol-treated Embryos Differentially mentioning

confidence: 99%

Chronic cortisol exposure in early development leads to neuroendocrine dysregulation in adulthood

Hartig

¹

,

Zhu

²

,

King

³

et al. 2020

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Objective: Chronic early life stress can affect development of the neuroendocrine stress system, leading to its persistent dysregulation and consequently increased disease risk in adulthood. One contributing factor is thought to be epigenetic programming in response to chronic cortisol exposure during early development. We have previously shown that zebrafish embryos treated chronically with cortisol develop into adults with constitutively elevated whole-body cortisol and aberrant immune gene expression. Here we further characterize that phenotype by assessing persistent effects of the treatment on cortisol tissue distribution and dynamics, chromatin accessibility, and activities of glucocorticoid-responsive regulatory genes klf9 and fkbp5. To that end cortisol levels in different tissues of fed and fasted adults were measured using ELISA, open chromatin in adult blood cells was mapped using ATAC-seq, and gene activity in adult blood and brain cells was measured using qRT-PCR. Results: Adults derived from cortisol-treated embryos have elevated whole-body cortisol with aberrantly regulated tissue distribution and dynamics that correlate with differential activity of klf9 and fkbp5 in blood and brain.

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“…2B). Interestingly both klf9 and per1a are involved in circadian regulation, and both have been shown to be GR targets in other vertebrate models [6][7][8]45 . Of these, only klf9 was found to be upregulated in response to chronic cortisol treatment in all three of our RNA-seq experiments (Fig.…”

Section: Discussionmentioning

confidence: 99%

Klf9 is a key feedforward regulator of the transcriptomic response to glucocorticoid receptor activity

Gans

¹

,

Hartig

²

,

Zhu

³

et al. 2019

Preprint

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The zebrafish has recently emerged as a model system for investigating the developmental roles of glucocorticoid signaling and the mechanisms underlying glucocorticoid-induced developmental programming. To assess the role of the Glucocorticoid Receptor (GR) in such programming, we used CRISPR-Cas9 to produce a new frameshift mutation, GR 369-, which eliminates all potential in-frame initiation codons upstream of the DNA binding domain. Using RNA-seq to ask how this mutation affects the larval transcriptome under both normal conditions and with chronic cortisol treatment, we find that GR mediates most of the effects of the treatment, and paradoxically, that the transcriptome of cortisol-treated larvae is more like that of larvae lacking a GR than that of larvae with a GR, suggesting that the cortisol-treated larvae develop GR resistance. The one transcriptional regulator that was both underexpressed in GR 369larvae and consistently overexpressed in cortisol-treated larvae was klf9. We therefore used CRISPR-Cas9-mediated mutation of klf9 and RNA-seq to assess Klf9-dependent gene expression in both normal and cortisol-treated larvae. Our results indicate that Klf9 contributes significantly to the transcriptomic response to chronic cortisol exposure, mediating the upregulation of proinflammatory genes that we reported previously.

show abstract

In-vivo regulation of Krüppel-like factor 9 by corticosteroids and their receptors across tissues in tadpoles of Xenopus tropicalis

Cited by 17 publications

References 36 publications

Klf9 is a key feedforward regulator of the transcriptomic response to glucocorticoid receptor activity

Klf9 is a key feedforward regulator of the transcriptomic response to glucocorticoid receptor activity

Chronic cortisol exposure in early development leads to neuroendocrine dysregulation in adulthood

Klf9 is a key feedforward regulator of the transcriptomic response to glucocorticoid receptor activity

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