scholarly journals Characterization of mitochondrial replication and transcription control during rat early development in vivo and in vitro

Reproduction ◽  
2007 ◽  
Vol 133 (2) ◽  
pp. 423-432 ◽  
Author(s):  
Yuichi Kameyama ◽  
France Filion ◽  
Jae Gyu Yoo ◽  
Lawrence C Smith

In vitroculture (IVC), used in assisted reproductive technologies, is a major environmental stress on the embryo. To evaluate the effect of IVC on mitochondrial transcription and the control of mtDNA replication, we measured the mtDNA copy number and relative amount of mRNA for mitochondrial-related genes in individual rat oocytes, zygotes and embryos using real-time PCR. The average mtDNA copy number was 147 600 (±3000) in metaphase II oocytes. The mtDNA copy number was stable throughoutin vivoearly development and IVC induced an increase in mtDNA copy number from the 8-cell stage onwards.GapdmRNA levels vary during early development and IVC did not change the patterns of these housekeeping gene transcripts.PolrmtmRNA levels did not vary during early development up to the morula stage but increased at the blastocyst stage. IVC induced the up-regulation ofPolrmtmRNA, one of the key genes regulating mtDNA transcription and replication, at the blastocyst stage. An increase inmt-Nd4mRNA preceded the blastocyst-related event observed in nuclear-encodedGapdandPolrmt, suggesting that the expression of mitochondrial encoded genes is controlled differently from nuclear encoded genes. We conclude that the IVC system can perturb mitochondrial transcription and the control of mtDNA replication in rat embryos. This perturbation of mtDNA regulation may be responsible for the abnormal physiology, metabolism and viability ofin vitro-derived embryos.

Zygote ◽  
2006 ◽  
Vol 14 (1) ◽  
pp. 81-87 ◽  
Author(s):  
P.N. Moreira ◽  
R. Fernández-Gonzalez ◽  
M.A. Ramirez ◽  
M. Pérez-Crespo ◽  
D. Rizos ◽  
...  

It is well known that the preimplantation culture environment to which embryos are exposed influences the expression of developmentally important genes. Recently, it has been reported that MEMα, a culture medium commonly used for somatic cells, allows high rates of preimplantation development and development to term of mouse somatic cell nuclear transfer (SCNT) embryos. The objective of this study was to compare the differential effects of this medium and of the nuclear transfer procedure on the relative mRNA abundance of several genes with key roles during preimplantation. The relative mRNA levels of nine genes (Glut 1, Glut 5, G6PDH, Bax, Survivin, Gpx 1, Oct4, mTert and IGF2bp1) were quantified at blastocyst stage on cumulus cell cloned embryos cultured in MEMα, as well as on in vivo cultured and MEMα cultured controls. Only three of the nine transcripts analysed (Glut 5, Gpx 1 and Igf2bp1) were significantly down-regulated at blastocyst stage in in vitro produced controls. However, most genes analysed in our MEMα cultured cloned embryos showed altered transcription levels. Interestingly, between cloned and in vitro produced controls only the transcription levels measured for Glut 1 were significantly different. This result suggests that Glut 1 may be a good marker for embryo quality after cumulus cell nuclear transfer.


2008 ◽  
Vol 20 (1) ◽  
pp. 169 ◽  
Author(s):  
C. E. McHughes ◽  
G. K. Springer ◽  
L. D. Spate ◽  
R. Li ◽  
R. J. Woods ◽  
...  

Identification of transcripts that are present at key development stages of preimplantation embryos is critical for a better understanding of early embryogenesis. To that end, this project had two goals. The first was to characterize the relative abundance of multiple transcripts during several developmental stages, including metaphase II-stage oocytes (MPII), and 2-cell-stage (2-cell), precompact morula (PCM), and in vitro-produced blastocyst-stage (IVTBL) embryos. The second was to characterize differences in the relative abundance of transcripts present in in vivo- (IVVBL), in vitro-, and nuclear transfer-produced (NTBL) blastocysts. It was our hypothesis that the identification of differentially represented transcripts from these stages would reveal not only developmentally important genes, but also genes that might be aberrantly expressed due to embryo production techniques. Individual clusters from a large bovine EST project (http://genome.rnet.missouri.edu/Bovine/), which focused on female reproductive tissues and embryos, were compared using Fisher's exact test weighted by number of transcripts per tissue by gene (SAS PROC FREQ; SAS Institute, Inc., Cary, NC, USA). Of the 3144 transcripts that were present during embryogenesis, 125 were found to be differentially represented (P < 0.01) in at least one pairwise comparison (Table 1). Some transcripts found to increase in representation from the MPII to the 2-cell stage include protein kinases, PRKACA and CKS1, as well as the metabolism-related gene, PTTG1. These same transcripts were also found to decrease in representation from the 2-cell to the PCM stage. RPL15 (translation) and FTH1 (immune function) were both more highly represented in the PCM than in the 2-cell stage. From PCM to IVTBL, we saw an increase in RPS11, another translation-related transcript. When comparing blastocyst-stage embryos from different production techniques, several transcripts involved in energy production (e.g., COX7B and COX8A) were found to be more highly represented in the NTBL than in the IVTBL. COX8A was also more highly represented in the IVVBL than in the IVTBL. By investigating these differentially represented transcripts, we will be able to better understand the developmental implications of embryo manipulation. We may also be able to better develop reproductive technologies that lead to in vitro- and nuclear transfer-derived embryos which more closely follow a normal program of development. Table 1. Differentially represented transcripts between developmental stages


Reproduction ◽  
2006 ◽  
Vol 131 (2) ◽  
pp. 233-245 ◽  
Author(s):  
Shahinaz H El Shourbagy ◽  
Emma C Spikings ◽  
Mariana Freitas ◽  
Justin C St John

The mitochondrion is explicitly involved in cytoplasmic regulation and is the cell’s major generator of ATP. Our aim was to determine whether mitochondria alone could influence fertilisation outcome. In vitro, oocyte competence can be assessed through the presence of glucose-6-phosphate dehydrogenase (G6PD) as indicated by the dye, brilliant cresyl blue (BCB). Using porcine in vitro fertilisation (IVF), we have assessed oocyte maturation, cytoplasmic volume, fertilisation outcome, mitochondrial number as determined by mtDNA copy number, and whether mitochondria are uniformly distributed between blastomeres of each embryo. After staining with BCB, we observed a significant difference in cytoplasmic volume between BCB positive (BCB+) and BCB negative (BCB−) oocytes. There was also a significant difference in mtDNA copy number between fertilised and unfertilised oocytes and unequal mitochondrial segregation between blastomeres during early cleavage stages. Furthermore, we have supplemented BCB− oocytes with mitochondria from maternal relatives and observed a significant difference in fertilisation outcomes following both IVF and intracytoplasmic sperm injection (ICSI) between supplemented, sham-injected and non-treated BCB− oocytes. We have therefore demonstrated a relationship between oocyte maturity, cytoplasmic volume, and fertilisation outcome and mitochondrial content. These data suggest that mitochondrial number is important for fertilisation outcome and embryonic development. Furthermore, a mitochondrial pre-fertilisation threshold may ensure that, as mitochondria are diluted out during post-fertilisation cleavage, there are sufficient copies of mtDNA per blastomere to allow transmission of mtDNA to each cell of the post-implantation embryo after the initiation of mtDNA replication during the early postimplantation stages.


Biomolecules ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1026
Author(s):  
Alberto Leguina-Ruzzi ◽  
Anežka Vodičková ◽  
Blanka Holendová ◽  
Vojtěch Pavluch ◽  
Jan Tauber ◽  
...  

Transcript levels for selected ATP synthase membrane FO-subunits—including DAPIT—in INS-1E cells were found to be sensitive to lowering glucose down from 11 mM, in which these cells are routinely cultured. Depending on conditions, the diminished mRNA levels recovered when glucose was restored to 11 mM; or were elevated during further 120 min incubations with 20-mM glucose. Asking whether DAPIT expression may be elevated by hyperglycemia in vivo, we studied mice with hyaluronic acid implants delivering glucose for up to 14 days. Such continuous two-week glucose stimulations in mice increased DAPIT mRNA by >5-fold in isolated pancreatic islets (ATP synthase F1α mRNA by 1.5-fold). In INS-1E cells, the glucose-induced ATP increment vanished with DAPIT silencing (6% of ATP rise), likewise a portion of the mtDNA-copy number increment. With 20 and 11-mM glucose the phosphorylating/non-phosphorylating respiration rate ratio diminished to ~70% and 96%, respectively, upon DAPIT silencing, whereas net GSIS rates accounted for 80% and 90% in USMG5/DAPIT-deficient cells. Consequently, the sufficient DAPIT expression and complete ATP synthase assembly is required for maximum ATP synthesis and mitochondrial biogenesis, but not for insulin secretion as such. Elevated DAPIT expression at high glucose further increases the ATP synthesis efficiency.


2017 ◽  
Vol 114 (29) ◽  
pp. E5796-E5804 ◽  
Author(s):  
Ye Yuan ◽  
Lee D. Spate ◽  
Bethany K. Redel ◽  
Yuchen Tian ◽  
Jie Zhou ◽  
...  

Assisted reproductive technologies in all mammals are critically dependent on the quality of the oocytes used to produce embryos. For reasons not fully clear, oocytes matured in vitro tend to be much less competent to become fertilized, advance to the blastocyst stage, and give rise to live young than their in vivo-produced counterparts, particularly if they are derived from immature females. Here we show that a chemically defined maturation medium supplemented with three cytokines (FGF2, LIF, and IGF1) in combination, so-called “FLI medium,” improves nuclear maturation of oocytes in cumulus–oocyte complexes derived from immature pig ovaries and provides a twofold increase in the efficiency of blastocyst production after in vitro fertilization. Transfer of such blastocysts to recipient females doubles mean litter size to about nine piglets per litter. Maturation of oocytes in FLI medium, therefore, effectively provides a fourfold increase in piglets born per oocyte collected. As they progress in culture, the FLI-matured cumulus–oocyte complexes display distinctly different kinetics of MAPK activation in the cumulus cells, much increased cumulus cell expansion, and an accelerated severance of cytoplasmic projections between the cumulus cells outside the zona pellucida and the oocyte within. These events likely underpin the improvement in oocyte quality achieved by using the FLI medium.


2005 ◽  
Vol 17 (2) ◽  
pp. 265
Author(s):  
H. Offenberg ◽  
P.D. Thomsen

It is known that culture conditions can alter gene expression of the pre-implantation embryo. We have previously shown that aquaporins (AQPs) are expressed in the mouse embryo and that they are involved in the passage of water across the trophoblast cells during blastocyst formation. This study was conducted to investigate whether AQP mRNA abundance is altered by culturing embryos in vitro compared to in vivo developed embryos. Furthermore we wanted to investigate if AQP mRNA abundance was influenced by the osmolality of the media. It is possible to compare the effect of hyperosmolality that the embryo may be able to compensate for by adding glycerol which can cross some AQPs, compared to the addition of sucrose which can not cross the membranes. Mouse embryos were obtained by superovulating B6D2F1 mice followed by culture of the flushed presumptive zygotes in KSOM to the blastocyst stage (in vitro) or by flushing blastocysts from the uterus (in vivo). For the study of the influence of osmolality on AQP mRNA abundance, zygotes were flushed and cultured to the compacted 8-cell stage and then placed in media of increasing osmolality, using either glycerol or sucrose. The osmolalities of the media were 243 (control), 300, 350, and 400 mOsm. Embryos were cultured to the blastocyst stage and frozen in liquid nitrogen. Embryonic RNA was extracted using a Dynabeads mRNA Capture kit (Dynal, Oslo, Norway). Real time PCR was performed on embryonic cDNA on a Lightcycler (Roche Diagnostics, 2650 Hvidovre, Denmark) using aquaporin-specific primers and primers for β-actin and GAPDH. The results of the quantitative RT-PCR analysis showed that in vitro-cultured embryos had a lower mRNA abundance for AQP 8, 9, and 11 compared to the in vivo-developed embryos but that the AQP 3 mRNA abundance was unaltered. Analysis of the housekeeping genes showed that GAPDH mRNA levels were unchanged in vitro, whereas β-actin was up-regulated in vitro. The osmotically challenged embryos showed the following blastocyst rates compared to the controls: glycerol 300: 100%; glycerol 350: 100%; glycerol 400: 100%; sucrose 300: 100%; sucrose 350: 78%; and sucrose 400: 0%. Thus, glycerol up to 400 mOsm had no effect on blastocyst rates, whereas addition of sucrose reduced blastocyst formation, with a total inhibition at 400 mOsm. Analysis of the mRNA abundance showed a reduction of AQP 8 in the glycerol solutions. The level was reduced to 30% of the control group at 300 mOsm, to 27% at 350 mOsm and to 8% at 400 mOsm. There was no corresponding reduction of AQP 8 mRNA abundance in sucrose solutions. Further, AQP 3, 7, 9, and 11 mRNA levels as well as β-actin and GAPDH mRNA levels were unaltered in the osmotically challenged embryos. In conclusion, this study shows that embryonic culture affects the abundance of several AQPs and that compensation of a glycerol-induced osmotical challenge induces down-regulation of AQP 8 expression. Embryos tolerate high glycerol concentrations better than high sucrose concentrations but the possible role of AQP 8 in this process is unclear at present.


Animals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2304
Author(s):  
Achraf Benammar ◽  
Emilie Derisoud ◽  
François Vialard ◽  
Eric Palmer ◽  
Jean Marc Ayoubi ◽  
...  

Although there are large differences between horses and humans for reproductive anatomy, follicular dynamics, mono-ovulation, and embryo development kinetics until the blastocyst stage are similar. In contrast to humans, however, horses are seasonal animals and do not have a menstrual cycle. Moreover, horse implantation takes place 30 days later than in humans. In terms of artificial reproduction techniques (ART), oocytes are generally matured in vitro in horses because ovarian stimulation remains inefficient. This allows the collection of oocytes without hormonal treatments. In humans, in vivo matured oocytes are collected after ovarian stimulation. Subsequently, only intra-cytoplasmic sperm injection (ICSI) is performed in horses to produce embryos, whereas both in vitro fertilization and ICSI are applied in humans. Embryos are transferred only as blastocysts in horses. In contrast, four cells to blastocyst stage embryos are transferred in humans. Embryo and oocyte cryopreservation has been mastered in humans, but not completely in horses. Finally, both species share infertility concerns due to ageing and obesity. Thus, reciprocal knowledge could be gained through the comparative study of ART and infertility treatments both in woman and mare, even though the horse could not be used as a single model for human ART.


2020 ◽  
Vol 26 (45) ◽  
pp. 5783-5792
Author(s):  
Kholood Abid Janjua ◽  
Adeeb Shehzad ◽  
Raheem Shahzad ◽  
Salman Ul Islam ◽  
Mazhar Ul Islam

There is compelling evidence that drug molecules isolated from natural sources are hindered by low systemic bioavailability, poor absorption, and rapid elimination from the human body. Novel approaches are urgently needed that could enhance the retention time as well as the efficacy of natural products in the body. Among the various adopted approaches to meet this ever-increasing demand, nanoformulations show the most fascinating way of improving the bioavailability of dietary phytochemicals through modifying their pharmacokinetics and pharmacodynamics. Curcumin, a yellowish pigment isolated from dried ground rhizomes of turmeric, exhibits tremendous pharmacological effects, including anticancer activities. Several in vitro and in vivo studies have shown that curcumin mediates anticancer effects through the modulation (upregulation and/or downregulations) of several intracellular signaling pathways both at protein and mRNA levels. Scientists have introduced multiple modern techniques and novel dosage forms for enhancing the delivery, bioavailability, and efficacy of curcumin in the treatment of various malignancies. These novel dosage forms include nanoparticles, liposomes, micelles, phospholipids, and curcumin-encapsulated polymer nanoparticles. Nanocurcumin has shown improved anticancer effects compared to conventional curcumin formulations. This review discusses the underlying molecular mechanism of various nanoformulations of curcumin for the treatment of different cancers. We hope that this study will make a road map for preclinical and clinical investigations of cancer and recommend nano curcumin as a drug of choice for cancer therapy.


BMC Cancer ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Chengwu Xiao ◽  
Wei Zhang ◽  
Meimian Hua ◽  
Huan Chen ◽  
Bin Yang ◽  
...  

Abstract Background The tripartite motif (TRIM) family proteins exhibit oncogenic roles in various cancers. The roles of TRIM27, a member of the TRIM super family, in renal cell carcinoma (RCC) remained unexplored. In the current study, we aimed to investigate the clinical impact and roles of TRIM27 in the development of RCC. Methods The mRNA levels of TRIM27 and Kaplan–Meier survival of RCC were analyzed from The Cancer Genome Atlas database. Real-time PCR and Western blotting were used to measure the mRNA and protein levels of TRIM27 both in vivo and in vitro. siRNA and TRIM27 were exogenously overexpressed in RCC cell lines to manipulate TRIM27 expression. Results We discovered that TRIM27 was elevated in RCC patients, and the expression of TRIM27 was closely correlated with poor prognosis. The loss of function and gain of function results illustrated that TRIM27 promotes cell proliferation and inhibits apoptosis in RCC cell lines. Furthermore, TRIM27 expression was positively associated with NF-κB expression in patients with RCC. Blocking the activity of NF-κB attenuated the TRIM27-mediated enhancement of proliferation and inhibition of apoptosis. TRIM27 directly interacted with Iκbα, an inhibitor of NF-κB, to promote its ubiquitination, and the inhibitory effects of TRIM27 on Iκbα led to NF-κB activation. Conclusions Our results suggest that TRIM27 exhibits an oncogenic role in RCC by regulating NF-κB signaling. TRIM27 serves as a specific prognostic indicator for RCC, and strategies targeting the suppression of TRIM27 function may shed light on future therapeutic approaches.


2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii406-iii406
Author(s):  
Kübra Taban ◽  
David Pauck ◽  
Mara Maue ◽  
Viktoria Marquardt ◽  
Hua Yu ◽  
...  

Abstract Medulloblastoma (MB) is the most common malignant brain tumor in children and is frequently metastatic at diagnosis. Treatment with surgery, radiation and multi-agent chemotherapy may leave survivors of these brain tumors with long-term deficits as a consequence. One of the four consensus molecular subgroups of MB is the MYC-driven group 3 MB, which is the most malignant type and has a poor prognosis under current therapy. Thus, it is important to discover more effective targeted therapeutic approaches. We conducted a high-throughput drug screening to identify novel compounds showing efficiency in group 3 MB using both clinically established inhibitors (n=196) and clinically-applicable compounds (n=464). More than 20 compounds demonstrated a significantly higher anti-tumoral effect in MYChigh (n=7) compared to MYClow (n=4) MB cell models. Among these compounds, Navitoclax and Clofarabine showed the strongest effect in inducing cell cycle arrest and apoptosis in MYChigh MB models. Furthermore, we show that Navitoclax, an orally bioavailable and blood-brain barrier passing anti-cancer drug, inhibits specifically Bcl-xL proteins. In line, we found a significant correlation between BCL-xL and MYC mRNA levels in 763 primary MB patient samples (Data source: “R2 https://hgserver1.amc.nl”). In addition, Navitoclax and Clofarabine have been tested in cells obtained from MB patient-derived-xenografts, which confirmed their specific efficacy in MYChigh versus MYClow MB. In summary, our approach has identified promising new drugs that significantly reduce cell viability in MYChigh compared to MYClow MB cell models. Our findings point to novel therapeutic vulnerabilities for MB that need to be further validated in vitro and in vivo.


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