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Xie Q, Liao Q, Wang L, Zhang Y, Chen J, Bai H, Li K, Ai J. The Dominant Mechanism of Cyclophosphamide-Induced Damage to Ovarian Reserve: Premature Activation or Apoptosis of Primordial Follicles? Reprod Sci 2024; 31:30-44. [PMID: 37486531 DOI: 10.1007/s43032-023-01294-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 06/30/2023] [Indexed: 07/25/2023]
Abstract
Cyclophosphamide (CPM), a part of most cancer treatment regimens, has demonstrated high gonadal toxicity in females. Initially, CPM is believed to damage the ovarian reserve by premature activation of primordial follicles, for the fact that facing CPM damage, primordial oocytes show the activation of PTEN/PI3K/AKT pathways, accompanied by accelerated activation of follicle developmental waves. Meanwhile, primordial follicles are dormant and not considered the target of CPM. However, many researchers have found DNA DSBs and apoptosis within primordial oocytes under CPM-induced ovarian damage instead of premature accelerated activation. A stricter surveillance system of DNA damage is also thought to be in primordial oocytes. So far, the apoptotic death mechanism is considered well-proved, but the premature activation theory is controversial and unacceptable. The connection between the upregulation of PTEN/PI3K/AKT pathways and DNA DSBs and apoptosis within primordial oocytes is also unclear. This review aims to highlight the flaw and/or support of the disputed premature activation theory and the apoptosis mechanism to identify the underlying mechanism of CPM's injury on ovarian reserve, which is crucial to facilitate the discovery and development of effective ovarian protectants. Ultimately, this review finds no good evidence for follicle activation and strong consistent evidence for apoptosis.
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Affiliation(s)
- Qin Xie
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
- Department of Reproductive Medicine Center, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, No.136, Jingzhou Road, Xiangcheng District, Xiangyang, 441021, Hubei Province, People's Republic of China
| | - Qiuyue Liao
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Lingjuan Wang
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Yan Zhang
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Jing Chen
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Hualin Bai
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Kezhen Li
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
| | - Jihui Ai
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
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Greenberg DS, Tzur Y, Soreq H. The Use of Gapmers for In Vivo Suppression of Hepatic mRNA Targets. Methods Mol Biol 2021; 2176:177-184. [PMID: 32865791 DOI: 10.1007/978-1-0716-0771-8_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
This chapter describes the use of locked nucleic acid (LNA) GapmeRs for the in vivo knockdown of specific mRNAs in the mouse liver and phenotype analysis. LNA GapmeRs may be tested for efficacy by transfection in cultured cells. They are delivered into mice in vivo by intravenous tail injection .
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Affiliation(s)
- David S Greenberg
- The Life Sciences Institute and The Edmond and Lili Safra Center of Brain Science, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Yonat Tzur
- The Life Sciences Institute and The Edmond and Lili Safra Center of Brain Science, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Hermona Soreq
- The Life Sciences Institute and The Edmond and Lili Safra Center of Brain Science, The Hebrew University of Jerusalem, Jerusalem, Israel.
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Haig D, Mainieri A. The Evolution of Imprinted microRNAs and Their RNA Targets. Genes (Basel) 2020; 11:genes11091038. [PMID: 32899179 PMCID: PMC7564603 DOI: 10.3390/genes11091038] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 08/26/2020] [Accepted: 09/01/2020] [Indexed: 12/19/2022] Open
Abstract
Mammalian genomes contain many imprinted microRNAs. When an imprinted miRNA targets an unimprinted mRNA their interaction may have different fitness consequences for the loci encoding the miRNA and mRNA. In one possible outcome, the mRNA sequence evolves to evade regulation by the miRNA by a simple change of target sequence. Such a response is unavailable if the targeted sequence is strongly constrained by other functions. In these cases, the mRNA evolves to accommodate regulation by the imprinted miRNA. These evolutionary dynamics are illustrated using the examples of the imprinted C19MC cluster of miRNAs in primates and C2MC cluster in mice that are paternally expressed in placentas. The 3′ UTR of PTEN, a gene with growth-related and metabolic functions, appears to be an important target of miRNAs from both clusters.
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Abstract
MicroRNAs (miRNAs) are short, noncoding RNAs that are evolutionarily conserved across many different species. miRNA regulation of gene expression, specifically in the context of the mammalian brain, has been well characterized; however, the regulation of miRNA degradation is still a focus of ongoing research. This review focuses on recent findings concerning the cellular mechanisms that govern miRNA degradation, with an emphasis on target-mediated miRNA degradation and how this phenomenon is uniquely poised to maintain homeostasis in neuronal systems.
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Affiliation(s)
- Chun K Kim
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois
| | - Toni R Pak
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois
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How Complementary Targets Expose the microRNA 3' End for Tailing and Trimming during Target-Directed microRNA Degradation. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2020; 84:179-183. [PMID: 32019864 DOI: 10.1101/sqb.2019.84.039321] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
microRNAs (miRNAs) are crucial for posttranscriptional regulation of messenger RNAs. "Classical" miRNA targets predominantly interact with the miRNA seed sequence located near the miRNA 5' end. Interestingly, certain transcripts that exhibit extensive complementarity to the miRNAs 3' region, instead of being subjected to regulation, induce miRNA decay in a process termed target-directed miRNA degradation (TDMD). Here, we review recent advances in understanding the molecular mechanisms of TDMD. Specifically, we discuss how extensive miRNA complementarity to TDMD-inducing targets results in displacement of the miRNA 3' end from its protective pocket in the Argonaute protein. Unprotected miRNA 3' ends are then available for enzymatic attack by still-unidentified cellular enzymes. Identification of these cellular enzymes and discovery of additional TDMD-inducing transcripts are subjects for future research.
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