Tamoxifen administration routes and dosage for inducible Cre-mediated gene disruption in mouse hearts

Andersson, Kristin B.; Winer, Lisbeth H.; Mørk, Halvor K.; Molkentin, Jeffery D.; Jaisser, Frédéric

doi:10.1007/s11248-009-9342-4

Cited by 60 publications

(52 citation statements)

References 22 publications

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“…Using a tamoxifen-dependent Cre recombinase system, we now demonstrate that decreasing liver PTP1B by ∼50% in obese and insulin-resistant adult mice leads to a reversal of glucose intolerance and improvements in lipid homeostasis, and that these effects are manifested within just a matter of weeks after hepatic PTP1B knockdown. As expected, and reported by others, oral tamoxifen treatment caused a transient decrease in body weight in both groups of mice [32][33][34]. As with other mouse models of Ptp1b-specific deletion [17,22], body weight of the inducible liver-specific Ptp1b knockout mice did not differ from that of control mice.…”

Section: Discussionsupporting

confidence: 89%

Inducible liver-specific knockdown of protein tyrosine phosphatase 1B improves glucose and lipid homeostasis in adult mice

et al. 2013

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Aims/hypothesis Protein tyrosine phosphatase 1B (PTP1B) is a key negative regulator of insulin signalling. Hepatic PTP1B deficiency, using the Alb-Cre promoter to drive Ptp1b deletion from birth in mice, improves glucose homeostasis, insulin sensitivity and lipid metabolism. The aim of this study was to investigate the therapeutic potential of decreasing liver PTP1B levels in obese and insulinresistant adult mice. Methods Inducible Ptp1b liver-specific knockout mice were generated using SA-Cre-ER T2 mice crossed with Ptp1b floxed (Ptp1b fl/fl ) mice. Mice were fed a high-fat diet (HFD) for 12 weeks to induce obesity and insulin resistance. Tamoxifen was administered in the HFD to induce liverspecific deletion of Ptp1b (SA-Ptp1b −/− mice). Body weight, glucose homeostasis, lipid homeostasis, serum adipokines, insulin signalling and endoplasmic reticulum (ER) stress were examined.Results Despite no significant change in body weight relative to HFD-fed Ptp1b fl/fl control mice, HFD-fed SAPtp1b −/− mice exhibited a reversal of glucose intolerance as determined by improved glucose and pyruvate tolerance tests, decreased fed and fasting blood glucose and insulin levels, lower HOMA of insulin resistance, circulating leptin, serum and liver triacylglycerols, serum NEFA and decreased HFD-induced ER stress. This was associated with decreased glycogen synthase, eukaryotic translation initiation factor-2α kinase 3, eukaryotic initiation factor 2α and c-Jun NH 2 -terminal kinase 2 phosphorylation, and decreased expression of Pepck. Conclusions/interpretation Inducible liver-specific PTP1B knockdown reverses glucose intolerance and improves lipid homeostasis in HFD-fed obese and insulin-resistant adult mice. This suggests that knockdown of liver PTP1B in individuals who are already obese/insulin resistant may have relatively rapid, beneficial therapeutic effects.

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Section: Discussionsupporting

confidence: 89%

Inducible liver-specific knockdown of protein tyrosine phosphatase 1B improves glucose and lipid homeostasis in adult mice

et al. 2013

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“…There are several potential strategies that could be utilized to avoid Cre-mediated cardiotoxicity, including alterations in the dose of TAM, the frequency of administration, as well as the route of administration. To this end, effective cardiac-specific deletion of the SERCA2 gene was reported following two intraperitoneal injections of TAM at a dose of 80 mg/kg as well as oral administration of TAM via cakes or as nonpelleted feed (3). While both of these methods were effective in deleting SERCA2 levels in the hearts, assessment of cardiac function was not performed in the study, so it is difficult to determine if the mice exhibited the transient loss of systolic function observed in the current study.…”

Section: Discussionmentioning

confidence: 99%

Systolic dysfunction in cardiac-specific ligand-inducible MerCreMer transgenic mice

Hall

Smith

Hall

et al. 2011

American Journal of Physiology-Heart and Circulatory Physiology

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The Cre-loxP system is a useful tool to study the physiological effects of gene knockout in the heart. One limitation with using this system in the heart is the toxic effect of chronic expression of the Cre recombinase. To circumvent this limitation, a widely used inducible cardiac-specific model, Myh6-MerCreMer (Cre), using tamoxifen (TAM) to activate Cre has been developed. The current study examined cardiac function in Cre-positive C57B/J6 mice exposed to one, three, or five daily doses of a 40 mg/kg TAM to induce Cre activity specifically in the heart. Echocardiography demonstrated no statistically significant differences in systolic function (SF) at baseline as assessed by fractional shortening. In mice exposed to five injections, a significant fall in all determinants of SF was observed 6 days after TAM was initiated. However, SF returned to baseline levels 10 days after TAM initiation although the hearts exhibited significant hypertrophy. Heart weight-to-tibia length ratios were 73 ± 3, 78.5 ± 6, and 87.6 ± 9 mg/cm for one, three, and five TAM injections, respectively. TAM had no effect on cardiac function or hypertrophy in Cre-negative mice. Cre-positive mice receiving five TAM injections had significant reductions in cardiac mitochondrial ATP and significant reductions in the expression of proteins important for the regulation of cardiac oxidative phosphorylation including peroxisome proliferator-activated receptor-γ coactivator-1α and pyruvate dehydrogenase kinase-4. Thus inducible cardiac-specific activation of Cre recombinase caused a transient decline in SF that was dependent on the number of TAM doses and associated with significant hypertrophy and alterations in mitochondrial ATP and important proteins involved in the regulation of cardiac oxidative phosphorylation.

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“…Oral administration of TAM in the chow may also be used for gene disruption in models using the MCM transgene (3,12) and is shown to lead to complete recombination in cardiomyocytes (3). A limitation of administrating TAM to the animal through chow is the uncertainty regarding the amount of food consumed by each individual.…”

Section: Discussionmentioning

confidence: 99%

Cre-loxP DNA recombination is possible with only minimal unspecific transcriptional changes and without cardiomyopathy in Tg(αMHC-MerCreMer) mice

Hougen

Aronsen

Stokke

et al. 2010

American Journal of Physiology-Heart and Circulatory Physiology

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Cre-loxP technology for conditional gene inactivation is a powerful tool in cardiovascular research. Induction of gene inactivation can be carried out by per oral or intraperitoneal tamoxifen administration. Unintended transient cardiomyopathy following tamoxifen administration for gene inactivation has recently been reported. We aimed to develop a protocol for tamoxifen-induced gene inactivation with minimal effects on gene transcription and in vivo cardiac function, allowing studies of acute loss of the targeted gene. In mRNA microarrays, 35% of the 34,760 examined genes were significantly regulated in MCM(+/0) compared with wild type. In MCM(+/0), we found a correlation between tamoxifen dose and degree of gene regulation. Comparing one and four intraperitoneal injections of 40 mg·kg(-1)·day(-1) tamoxifen, regulated genes were reduced to 1/5 in the single injection group. Pronounced alteration in protein abundance and acute cardiomyopathy were observed after the four-injection protocols but not the one-injection protocol. For verification of gene inactivation following one injection of tamoxifen, this protocol was applied to MCM(+/0)/Serca2(fl/fl). Serca2 mRNA levels and protein abundance followed the same pattern of decline with one and four tamoxifen injections. The presence of the MCM transgene induced major alterations of gene expression while administration of tamoxifen induced additional but less gene regulation. Thus nonfloxed MCM(+/0) should be considered as controls for mice that carry both a floxed gene of interest and the MCM transgene. One single tamoxifen injection administered to MCM(+/0)/Serca2(fl/fl) was sufficient for target gene inactivation, without acute cardiomyopathy, allowing acute studies subsequent to gene inactivation.

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Tamoxifen administration routes and dosage for inducible Cre-mediated gene disruption in mouse hearts

Cited by 60 publications

References 22 publications

Inducible liver-specific knockdown of protein tyrosine phosphatase 1B improves glucose and lipid homeostasis in adult mice

Inducible liver-specific knockdown of protein tyrosine phosphatase 1B improves glucose and lipid homeostasis in adult mice

Systolic dysfunction in cardiac-specific ligand-inducible MerCreMer transgenic mice

Cre-loxP DNA recombination is possible with only minimal unspecific transcriptional changes and without cardiomyopathy in Tg(αMHC-MerCreMer) mice

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