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Statins inhibit blastocyst formation by preventing geranylgeranylation.
Mol Hum Reprod. 2016 05; 22(5):350-63.MH

Abstract

STUDY HYPOTHESIS

Statins, inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase of the mevalonate pathway and prescription drugs that treat hypercholesterolemia, compromise preimplantation mouse development via modulation of HIPPO signaling.

STUDY FINDING

HMG-CoA reductase activity is required for trophectoderm specification, namely blastocyst cavity formation and Yes-associated protein (YAP) nuclear localization, through the production of isoprenoid geranylgeranyl pyrophosphate (GGPP) and the action of geranylgeranyl transferase.

WHAT IS KNOWN ALREADY

Previous studies have shown that treatment of mouse embryos with mevastatin prevents blastocyst formation, but how HMG-CoA reductase is involved in preimplantation development is unknown. HIPPO signaling regulates specification of the trophectoderm lineage of the mouse blastocyst by controlling the nuclear localization of YAP. In human cell lines, the mevalonate pathway regulates YAP to mediate self-renewal and survival through geranylgeranylation of RHO proteins. These studies suggest that in preimplantation development, statins may act through HIPPO pathway to interfere with trophectoderm specification and thereby inhibit blastocyst formation.

STUDY DESIGN, SAMPLES/MATERIALS, METHODS

Eight-cell stage (E2.5) mouse embryos were treated in hanging drop culture with chemical agents, namely statins (lovastatin, atorvastatin, cerivastatin and pravastatin), mevalonic acid (MVA), cholesterol, squalene, farnesyl pyrophosphate (FPP), geranylgeranyl pyrophosphate (GGPP), geranylgeranyltransferase inhibitor GGTI-298, RHO inhibitor I, and squalene synthase inhibitor YM-53601, up to the late blastocyst stage (E4.5). Efficiency of blastocyst formation was assessed based on gross morphology and the measurement of the cavity size using an image analysis software. Effects on cell lineages and HIPPO signaling were analyzed using immunohistochemistry with confocal microscopy based on the expression patterns of the lineage-specific markers and the nuclear accumulation of YAP. Effects on cell lineages were also examined by quantitative RT-PCR based on the transcript levels of the lineage-specific marker genes. Data were analyzed using one-way ANOVA and two-sample t-test.

MAIN RESULTS AND THE ROLE OF CHANCE

All four statins examined inhibited blastocyst formation. The adverse impact of statins was rescued by supplementation of MVA (P < 0.01) or GGPP (P < 0.01) but not squalene nor cholesterol. Blastocyst formation was also prevented by GGTI-298 (P < 0.01). These results indicate that HMG-CoA reductase activity is required for blastocyst formation mainly through the production of GGPP but not cholesterol. Inhibition of RHO proteins, known targets of geranylgeranylation, impaired blastocyst formation, which was not reversed by GGPP supplementation. Nuclear localization of YAP was diminished by statin treatment but fully restored by supplementation of MVA (P < 0.01) or GGPP (P < 0.01). This suggests that HIPPO signaling is regulated by GGPP-dependent mechanisms, possibly geranylgeranylation of RHO, to enable trophectoderm formation. YM-53601 prevented blastocyst formation (P < 0.01), but its adverse impact was not rescued by supplementation of squalene or cholesterol, suggesting that squalene synthesis inhibition was not the cause of blastocyst defects.

LIMITATIONS, REASONS FOR CAUTION

Analyses were conducted on embryos cultured ex vivo, but they enable the determination of specific concentrations that impair embryo development which can be compared with drug concentrations in the reproductive tract when testing in vivo impact of statins through animal experimentations. Also, analyses were conducted in only one species, the mouse. Epidemiological studies on the effects of various types of statins on the fertility of women are necessary.

WIDER IMPLICATIONS OF THE FINDINGS

Our study reveals how the mevalonate pathway is required for blastocyst formation and intersects with HIPPO pathway to provide a mechanistic basis for the embryotoxic effect of statins. This bears relevance for women who are taking statins while trying to conceive, since statins have potential to prevent the conceptus from reaching the blastocyst stage and to cause early conceptus demise.

LARGE SCALE DATA

Not applicable.

STUDY FUNDING AND COMPETING INTERESTS

This study was supported by grants from the George F. Straub Trust of the Hawaii Community Foundation (13ADVC-60315 to V.B.A.) and the National Institutes of Health, USA (P20GM103457 to V.B.A.). The authors have no conflict of interest to declare.

Authors+Show Affiliations

Institute for Biogenesis Research, Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI 96813, USA vernadet@hawaii.edu.Institute for Biogenesis Research, Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI 96813, USA.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

26908642

Citation

Alarcon, Vernadeth B., and Yusuke Marikawa. "Statins Inhibit Blastocyst Formation By Preventing Geranylgeranylation." Molecular Human Reproduction, vol. 22, no. 5, 2016, pp. 350-63.
Alarcon VB, Marikawa Y. Statins inhibit blastocyst formation by preventing geranylgeranylation. Mol Hum Reprod. 2016;22(5):350-63.
Alarcon, V. B., & Marikawa, Y. (2016). Statins inhibit blastocyst formation by preventing geranylgeranylation. Molecular Human Reproduction, 22(5), 350-63. https://doi.org/10.1093/molehr/gaw011
Alarcon VB, Marikawa Y. Statins Inhibit Blastocyst Formation By Preventing Geranylgeranylation. Mol Hum Reprod. 2016;22(5):350-63. PubMed PMID: 26908642.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Statins inhibit blastocyst formation by preventing geranylgeranylation. AU - Alarcon,Vernadeth B, AU - Marikawa,Yusuke, Y1 - 2016/02/07/ PY - 2015/07/04/received PY - 2016/01/29/accepted PY - 2016/2/25/entrez PY - 2016/2/26/pubmed PY - 2018/1/23/medline KW - 3-hydroxy-3-methylglutaryl-coenzyme A reductase KW - CDX2 KW - HIPPO pathway KW - RHO KW - Yes-associated protein KW - fertility KW - mevalonate pathway KW - pluripotent KW - preimplantation KW - trophectoderm SP - 350 EP - 63 JF - Molecular human reproduction JO - Mol Hum Reprod VL - 22 IS - 5 N2 - STUDY HYPOTHESIS: Statins, inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase of the mevalonate pathway and prescription drugs that treat hypercholesterolemia, compromise preimplantation mouse development via modulation of HIPPO signaling. STUDY FINDING: HMG-CoA reductase activity is required for trophectoderm specification, namely blastocyst cavity formation and Yes-associated protein (YAP) nuclear localization, through the production of isoprenoid geranylgeranyl pyrophosphate (GGPP) and the action of geranylgeranyl transferase. WHAT IS KNOWN ALREADY: Previous studies have shown that treatment of mouse embryos with mevastatin prevents blastocyst formation, but how HMG-CoA reductase is involved in preimplantation development is unknown. HIPPO signaling regulates specification of the trophectoderm lineage of the mouse blastocyst by controlling the nuclear localization of YAP. In human cell lines, the mevalonate pathway regulates YAP to mediate self-renewal and survival through geranylgeranylation of RHO proteins. These studies suggest that in preimplantation development, statins may act through HIPPO pathway to interfere with trophectoderm specification and thereby inhibit blastocyst formation. STUDY DESIGN, SAMPLES/MATERIALS, METHODS: Eight-cell stage (E2.5) mouse embryos were treated in hanging drop culture with chemical agents, namely statins (lovastatin, atorvastatin, cerivastatin and pravastatin), mevalonic acid (MVA), cholesterol, squalene, farnesyl pyrophosphate (FPP), geranylgeranyl pyrophosphate (GGPP), geranylgeranyltransferase inhibitor GGTI-298, RHO inhibitor I, and squalene synthase inhibitor YM-53601, up to the late blastocyst stage (E4.5). Efficiency of blastocyst formation was assessed based on gross morphology and the measurement of the cavity size using an image analysis software. Effects on cell lineages and HIPPO signaling were analyzed using immunohistochemistry with confocal microscopy based on the expression patterns of the lineage-specific markers and the nuclear accumulation of YAP. Effects on cell lineages were also examined by quantitative RT-PCR based on the transcript levels of the lineage-specific marker genes. Data were analyzed using one-way ANOVA and two-sample t-test. MAIN RESULTS AND THE ROLE OF CHANCE: All four statins examined inhibited blastocyst formation. The adverse impact of statins was rescued by supplementation of MVA (P < 0.01) or GGPP (P < 0.01) but not squalene nor cholesterol. Blastocyst formation was also prevented by GGTI-298 (P < 0.01). These results indicate that HMG-CoA reductase activity is required for blastocyst formation mainly through the production of GGPP but not cholesterol. Inhibition of RHO proteins, known targets of geranylgeranylation, impaired blastocyst formation, which was not reversed by GGPP supplementation. Nuclear localization of YAP was diminished by statin treatment but fully restored by supplementation of MVA (P < 0.01) or GGPP (P < 0.01). This suggests that HIPPO signaling is regulated by GGPP-dependent mechanisms, possibly geranylgeranylation of RHO, to enable trophectoderm formation. YM-53601 prevented blastocyst formation (P < 0.01), but its adverse impact was not rescued by supplementation of squalene or cholesterol, suggesting that squalene synthesis inhibition was not the cause of blastocyst defects. LIMITATIONS, REASONS FOR CAUTION: Analyses were conducted on embryos cultured ex vivo, but they enable the determination of specific concentrations that impair embryo development which can be compared with drug concentrations in the reproductive tract when testing in vivo impact of statins through animal experimentations. Also, analyses were conducted in only one species, the mouse. Epidemiological studies on the effects of various types of statins on the fertility of women are necessary. WIDER IMPLICATIONS OF THE FINDINGS: Our study reveals how the mevalonate pathway is required for blastocyst formation and intersects with HIPPO pathway to provide a mechanistic basis for the embryotoxic effect of statins. This bears relevance for women who are taking statins while trying to conceive, since statins have potential to prevent the conceptus from reaching the blastocyst stage and to cause early conceptus demise. LARGE SCALE DATA: Not applicable. STUDY FUNDING AND COMPETING INTERESTS: This study was supported by grants from the George F. Straub Trust of the Hawaii Community Foundation (13ADVC-60315 to V.B.A.) and the National Institutes of Health, USA (P20GM103457 to V.B.A.). The authors have no conflict of interest to declare. SN - 1460-2407 UR - https://www.unboundmedicine.com/medline/citation/26908642/Statins_inhibit_blastocyst_formation_by_preventing_geranylgeranylation_ L2 - https://academic.oup.com/molehr/article-lookup/doi/10.1093/molehr/gaw011 DB - PRIME DP - Unbound Medicine ER -