Details of a Researcher - IWATA Hisataka

Papers - IWATA Hisataka

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Palmitic acid activates NLRP3 inflammasome and induces placental inflammation during pregnancy in mice

SANO Michiya, SHIMAZAKI Sayaka, KANEKO Yasuaki, KARASAWA Tadayoshi, TAKAHASHI Masafumi, OHKUCHI Akihide, TAKAHASHI Hironori, KUROSAWA Akira, TORII Yasushi, IWATA Hisataka, KUWAYAMA Takehito, SHIRASUNA Koumei

Journal of Reproduction and Development 66 ( 3 ) 241 - 248 2020

Language：English Publisher：The Society for Reproduction and Development

Maternal obesity is one of the major risk factors for pregnancy complications and is associated with low-grade chronic systemic inflammation due to higher levels of pro-inflammatory cytokines such as interleukin (IL)-1β. Pregnant women with obesity have abnormal lipid profiles, characterized by higher levels of free fatty acids, especially palmitic acid (PA). Previously, we reported that PA stimulated IL-1β secretion via activation of NLRP3 inflammasome in human placental cells. These observations led us to hypothesize that higher levels of PA induce NLRP3 inflammasome activation and placental inflammation, resulting in pregnancy complications. However, the effects of PA on NLRP3 inflammasome during pregnancy in vivo remain unclear. Therefore, PA solutions were administered intravenously into pregnant mice on day 12 of gestation. Maternal body weight was significantly decreased and absorption rates were significantly higher in PA-injected mice. The administration of PA significantly increased IL-1β protein and the mRNA expression of NLRP3 inflammasome components (NLRP3, ASC, and caspase-1) within the placenta. In murine placental cell culture, PA significantly stimulated IL-1β secretion, and this secretion was suppressed by a specific NLRP3 inhibitor (MCC950). Simultaneously, the number of macrophages/monocytes and neutrophils, together with the mRNA expression of these chemokines increased significantly in the placentas of PA-treated mice. Treatment with PA induced ASC assembling and IL-1β secretion in macrophages, and this PA-induced IL-1β secretion was significantly suppressed in NLRP3-knockdown macrophages. These results indicate that transient higher levels of PA exposure in pregnant mice activates NLRP3 inflammasome and induces placental inflammation, resulting in the incidence of absorption.

DOI： 10.1262/jrd.2020-007

PubMed

CiNii Articles

Effect of aging on mitochondria and metabolism of bovine granulosa cells International journal

NAGATA Shuta, TATEMATSU Kaoru, KANSAKU Kazuki, INOUE Yuki, KOBAYASHI Mitsuru, SHIRASUNA Koumei, IWATA Hisataka

Journal of Reproduction and Development 66 ( 6 ) 547 - 554 2020

Language：English Publishing type：Research paper (scientific journal) Publisher：The Society for Reproduction and Development

This study investigated the effect of aging on mitochondria in granulosa cells (GCs) collected from the antral follicles of young and aged cows (25–50 months and over 140 months in age, respectively). When GCs were cultured under 20% O2 for 4 days, mitochondrial DNA copy number (Mt-number), determined by real-time PCR, increased throughout the culture period, and the extent of increase was greater in the GCs of young cows than in those of old cows. In a second experiment, GCs were cultured under 20% O2 for 24 h. Protein levels of TOMM20 and TFAM in GCs were lower in aged cows than in young cows, and the amount of reactive oxygen species and the mitochondrial membrane potential were higher, whereas ATP content and proliferation activity were lower, respectively. Glucose consumption and lactate production were higher in the GCs of aged cows than in those of young cows. When GCs were cultured under 5% or 20% O2 for 24 h, low O2 decreased ATP content and increased glucose consumption in GCs of both age groups compared with high O2; however, low O2 decreased the Mt-number only in the GCs of young cows. In conclusion, we show that aging affects mitochondrial quantity, function, and response to differential O2 tensions in GCs.

DOI： 10.1262/jrd.2020-071

PubMed

CiNii Articles

Comparison of gene expression and mitochondria number between bovine blastocysts obtained in vitro and in vivo International journal

NOGUCHI Tatsuo, AIZAWA Takuro, MUNAKATA Yasuhisa, IWATA Hisataka

Journal of Reproduction and Development 66 ( 1 ) 35 - 39 2020

Language：English Publishing type：Research paper (scientific journal) Publisher：The Society for Reproduction and Development

Embryo transfer uses embryos developed in vivo or in vitro for cattle production, however there is a difference in the quality of the embryos obtained by the two methods. This study addresses the differences in gene expression between blastocysts developed in vitro and in vivo. In vivo blastocysts were flushed from the uteri of super-ovulated cows and blastocysts developed in vitro were derived from in vitro matured and fertilized embryos. The same batch of frozen bull sperm was used for insemination and in vitro fertilization. Blastocysts were then subjected to RNA sequencing. Differentially expressed genes upregulated in in vitro blastocysts were annotated to focal adhesion, extracellular matrix (ECM)-receptor interaction, and PI3K-Akt signaling and the genes that were upregulated in in vivo blastocysts were annotated to oxidation-reduction processes, mitochondrion organization, and mitochondrial translation. Although the total cell number of the two types of blastocysts was similar, the mitochondrial quantity (determined by mitochondrial DNA copy numbers and expression levels of TOMM20), and ATP content in the blastocysts were lower in in vivo blastocysts compared with those developed in vitro. In conclusion, RNAseq revealed differential molecular backgrounds between in vitro and in vivo developed blastocysts and mitochondrial number and function are responsible for these differences.

DOI： 10.1262/jrd.2019-100

PubMed

CiNii Articles

Comparative analysis of cell-free DNA content in culture medium and mitochondrial DNA copy number in porcine parthenogenetically activated embryos International journal

KOBAYASHI Mitsuru, ITO Jun, SHIRASUNA Koumei, KUWAYAMA Takehito, IWATA Hisataka

Journal of Reproduction and Development 66 ( 6 ) 539 - 546 2020

Language：English Publishing type：Research paper (scientific journal) Publisher：The Society for Reproduction and Development

We examined the effect of ploidy on mitochondrial DNA (mtDNA) copy number in embryos and the amount of cell-free mitochondrial and nucleic DNA content (cf-mtDNA and cf-nDNA) in spent culture medium (SCM). Oocytes collected from the ovaries were matured, activated, incubated in medium containing cycloheximide (CHX) or CHX and cytochalasin B (CB) for 4.5 h to produce haploid or diploid embryos (H-group and D-group embryos). These embryos were cultured for 7 days, and the blastocysts and SCM were examined. The amount of mtDNA and nDNA was determined by real-time PCR. The rate of development to the blastocyst stage was higher for the D-group than for the H-group. Moreover, D-group blastocysts had less mtDNA compared to the H-group blastocysts. After activation, the mitochondrial content was constant before the blastocyst stage in D-group embryos, but increased earlier in H-group embryos. The amount of cf-mtDNA in the SCM of D-group blastocysts was greater than that of H-group blastocysts. However, when the cf-mtDNA in the SCM of 2 cell-stage embryos (day 2 post-activation) was examined, the amount of cf-mtDNA was greater in the H-group than in the D-group embryos. When D-group embryos were cultured for 7 days, a significant correlation was observed between the total cell number of blastocysts and cf-nDNA content in the SCM. Hence, although careful consideration is needed regarding the time point for evaluating mtDNA content in the embryos and SCM, this study demonstrates that mtDNA in the embryos and SCM was affected by the ploidy of the embryos.

DOI： 10.1262/jrd.2020-097

PubMed

CiNii Articles

Cell-free DNA Content in Follicular Fluid: A Marker for the Developmental Ability of Porcine Oocytes Reviewed

Kana Ichikawa, Hidenori Shibahara, Komei Shirasuna, Takehito Kuwayama, Hisataka Iwata

Reproductive Medicine and Biology 19 ( 1 ) 95 - 103 2019.12