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Your search keyword '"Shirozu, Takahiro"' showing total 25 results
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25 results on '"Shirozu, Takahiro"'

2. Wolbachia infection in Aedes aegypti does not affect its vectorial capacity for Dirofilaria immitis.

Author

Shirozu, Takahiro, Regilme, Maria Angenica F., Ote, Manabu, Sasaki, Mizuki, Soga, Akira, Bochimoto, Hiroki, Kawabata, Hidenobu, Umemiya-Shirafuji, Rika, Kanuka, Hirotaka, and Fukumoto, Shinya

Subjects
*AEDES aegypti, *DIROFILARIA immitis, *MOSQUITO-borne diseases, *ARBOVIRUSES, *DENGUE viruses, *MOSQUITO control
Abstract

Mosquito-borne diseases such as dengue and filariasis are a growing public health concern in endemic countries. Biological approaches, such as the trans-infection of Wolbachia pipientis in mosquitoes, are an alternative vector control strategy, especially for arthropod-borne viruses such as dengue. In the present study, the effect of Wolbachia (wMel strain) on the vectorial capacity of Aedes aegypti for Dirofilaria immitis was studied. Our results showed that Wolbachia does not affect the phenotype of mosquito survival or the prevalence, number, and molting rate of third-stage larvae in both susceptible and resistant strains of Ae. aegypti. RNA-seq analysis of Malpighian tubules at 2 days post-infection with D. immitis showed the differentially expressed genes (DEGs) with and without wMel infection. No characteristic immune-related gene expression patterns were observed among the DEGs. No significant change in the amount of Wolbachia was observed in the Ae. aegypti after D. immitis infection. Our results suggest that infection of D. immitis in Ae. aegypti populations will not interfere with Wolbachia-based vector control strategies in dengue-endemic areas where cases of D. immitis are present. This study demonstrated the veterinary medical validity of a dengue control program using Wolbachia. [ABSTRACT FROM AUTHOR]

Published
2024
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5. Development of a novel rodent model for dog heartworm microfilaremia using the severe-combined immunodeficiency mouse.

Author

Mizuseki, Mihoko, Ikeda, Nao, Shirozu, Takahiro, Yamagishi, Maki, Oshiro, Sugao, and Fukumoto, Shinya

Subjects
DIROFILARIA immitis, SEVERE combined immunodeficiency, RODENTS, AEDES aegypti, PERIPHERAL circulation, MOSQUITO vectors
Abstract

Dirofilaria immitis is a mosquito-borne parasitic nematode that causes fatal heartworm disease in canids. The microfilariae are essential for research, including drug screening and mosquito-parasite interactions. However, no reliable methods for maintaining microfilaria long-term are currently available. Therefore, we used severe combined immunodeficiency (SCID) mice to develop a reliable method for maintaining D. immitis microfilaria. SCID mice were injected intravenously with microfilariae isolated from a D. immitis-infected dog. Microfilariae were detected in blood collected from the tail vein 218 days post-inoculation (dpi) and via cardiac puncture 296 dpi. Microfilariae maintained in and extracted from SCID mice showed infectivity and matured into third-stage larvae (L3s) in the vector mosquito Aedes aegypti. L3s can develop into the fourth stage larvae in vitro. Microfilariae from SCID mice respond normally to ivermectin in vitro. The microfilariae in SCID mice displayed periodicity in the peripheral circulation. The SCID mouse model aided in the separation of microfilariae from cryopreserved specimens. The use of SCID mice enabled the isolation and sustained cultivation of microfilariae from clinical samples. These findings highlight the usefulness of the SCID mouse model for studying D. immitis microfilaremia in canine heartworm research. [ABSTRACT FROM AUTHOR]

Published
2024
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16. Expression dynamics of bovine MX genes in the endometrium and placenta during early to mid pregnancy

Author

SHIROZU, Takahiro, SASAKI, Keisuke, KAWAHARA, Manabu, YANAGAWA, Yojiro, NAGANO, Masashi, YAMAUCHI, Nobuhiko, and TAKAHASHI, Masashi

Subjects
Myxovirus Resistance Proteins, Reverse Transcriptase Polymerase Chain Reaction, Placenta, Cow, Uterus, Gene Expression Regulation, Developmental, Pregnancy Proteins, MX, Alternative Splicing, Endometrium, Fetus, Pregnancy, Immune System, Interferon Type I, Animals, Pregnancy, Animal, Original Article, Cattle, Female, Embryo Implantation, Interferons, Signal Transduction
Abstract

MX belongs to a family of type I interferon (IFN)-stimulated genes, and the MX protein has antiviral activity. MX has at least two isoforms, known as MX1 and MX2, in mammals. Moreover, bovine MX1 has been found to have alternative splice variants—namely, MX1-a and MX1B. In ruminants, IFN-τ—a type I IFN—is temporarily produced from the conceptus before implantation and induces MX expression in the endometrium. However, the expression dynamics of MX after implantation are not clear. In the present study, we investigated the expression of MX1-a, MX1B and MX2 in the endometrium and placenta before and after implantation along with the expression of IFN-α, type I receptors (IFNAR1 and IFNAR2) and interferon regulatory factors (IRF3 and IRF9). Pregnant uterine samples were divided into five groups according to pregnancy days 14–18, 25–40, 50–70, 80–100, and 130–150. Tissue samples were collected from the intercaruncular endometrium (IC), caruncular endometrium (C) and fetal placenta (P). Although all the MX expressions were significantly higher in the IC and C at days 14–18, presumably caused by embryo-secreted IFN-τ stimulation, their expressions were also detectable in the IC, C and P after implantation. Furthermore, IFN-α expression was significantly higher in the IC. RT-PCR indicated IFNAR1, IFNAR2, IRF3 and IRF9 mRNA in all the tissues during pregnancy. These results suggest that all the MX genes are affected by the type I IFN pathway during pregnancy and are involved in an immune response to protect the mother and fetus.

Published
2015

17. Hot topic: Pregnancy-induced expression of interferon-stimulated genes in the cervical and vaginal mucosal membranes

Author

Kunii, Hiroki, Koyama, Keisuke, Ito, Tsukino, Suzuki, Toshiyuki, Balboula, Ahmed Z, Shirozu, Takahiro, Bai, Hanako, Nagano, Masashi, Kawahara, Manabu, Takahashi, Masashi, Kunii, Hiroki, Koyama, Keisuke, Ito, Tsukino, Suzuki, Toshiyuki, Balboula, Ahmed Z, Shirozu, Takahiro, Bai, Hanako, Nagano, Masashi, Kawahara, Manabu, and Takahashi, Masashi

Abstract

In ruminants, IFN-tau (IFNT) is a pregnancy recognition signal secreted by the embryonic trophectoderm before implantation, and it induces the expression of IFN-stimulated genes (ISG) in the uterine endometrium and blood leukocytes. The expression of ISG in blood leukocytes could indicate the presence of a viable conceptus before return of the next estrus; however, expression levels have high variation for confirming pregnancy. We hypothesized that the secreted IFNT in the uterus would affect ISG expression in cervical and vaginal tissues because they are directly adjacent to the uterus. To prove the hypothesis, we investigated the expression of 3 ISG (ISG15, MX1, and MX2) in cervical and vaginal mucosal membranes collected from pregnant (n = 12) and nonpregnant (n = 11) lactating Holstein cows at 17 to 18 d after artificial insemination. Mucosal membrane samples of the cervical canal near the external os (cervix) and deep vaginal wall surrounding the external os (vagina) were collected separately by simply scraping with a curette on d 17 or 18 of pregnancy (d 1 = ovulation), at which time IFNT secretion into the maternal uterus is maximal. After pregnancy diagnosis on d 30 and 60, separately collected samples confirmed as pregnant and nonpregnant were used for evaluation of the expression of IFN-stimulated protein 15 kDa (ISG15) and myxovirus-resistance protein 1 and 2 (MX1, MX2) with quantitative real-time PCR. The collected mucosal membrane samples from cervix contained mostly cell clots showing membrane structure and a low content of blood cells. The expression levels of all 3 genes were significantly increased in pregnant cows compared with nonpregnant cows in both cervical and vaginal samples. These results suggest that increased expression of ISG in the cervix and vagina is a pregnancy-associated phenomenon and is highly affected by IFNT secreted from the conceptus through the uterus.

Published
2018

20. Involvement of interferon-tau in the induction of apoptotic, pyroptotic, and autophagic cell death-related signaling pathways in the bovine uterine endometrium during early pregnancy

Author

SUZUKI, Toshiyuki, primary, SAKUMOTO, Ryosuke, additional, HAYASHI, Ken-Go, additional, OGISO, Takatoshi, additional, KUNII, Hiroki, additional, SHIROZU, Takahiro, additional, KIM, Sung-Woo, additional, BAI, Hanako, additional, KAWAHARA, Manabu, additional, KIMURA, Koji, additional, and TAKAHASHI, Masashi, additional

Published
2018
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21. Estrous cycle stage-dependent manner of type I interferon-stimulated genes induction in the bovine endometrium

Author

SHIROZU, Takahiro, primary, IWANO, Hiroki, additional, OGISO, Takatoshi, additional, SUZUKI, Toshiyuki, additional, BALBOULA, Ahmed Z., additional, BAI, Hanako, additional, KAWAHARA, Manabu, additional, KIMURA, Koji, additional, TAKAHASHI, Hitomi, additional, RULAN, Bai, additional, KIM, Sung-Woo, additional, YANAGAWA, Yojiro, additional, NAGANO, Masashi, additional, IMAKAWA, Kazuhiko, additional, and TAKAHASHI, Masashi, additional

Published
2017
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22. High frequencies of F1534C and V1016I kdrmutations and association with pyrethroid resistance in Aedes aegyptifrom Somgandé (Ouagadougou), Burkina Faso

Author

Sombié, Aboubacar, Saiki, Erisha, Yaméogo, Félix, Sakurai, Tatsuya, Shirozu, Takahiro, Fukumoto, Shinya, Sanon, Antoine, Weetman, David, McCall, Philip, Kanuka, Hirotaka, and Badolo, Athanase

Abstract

Resistance to pyrethroid insecticides involving kdrmutations is widespread in Aedes aegypti(L.) (Diptera: Culicidae) and potentially could impact control efforts in endemic countries. Dengue cases had been sporadic in Burkina Faso for over a decade prior to the 2016–2017 outbreak that resulted in 15,074 suspected cases and 36 deaths, mainly in Ouagadougou. These outbreaks highlighted the lack of information on numerous aspects of the biology, behaviour and insecticide status of local dengue vector populations that are fundamental to vector control. We investigated the insecticide resistance profiles and the kdrmutations involved in pyrethroid resistance of Ae. aegyptifrom Somgandé, a district of Ouagadougou. WHO bioassays revealed that the local Ae. aegyptipopulations were highly resistant to pyrethroids with mortalities of 15% for permethrin and 37% for deltamethrin. Resistance to carbamates was also detected with mortalities of 55% for propoxur and 90% for bendiocarb, but high mortalities (> 97%) to organophosphates (malathion and fenitrothion) indicated susceptibility. Allele-specific PCR and voltage-gated sodium channel gene sequencing showed a very high frequency (97%) of the F1534C kdrallele whilst the V1016I kdrmutation frequency was 46%. Association of dual-locus kdrmutations was detected for permethrin resistance. We conclude that in this locality of Burkina Faso, Ae. aegyptiis resistant to pyrethroid and carbamate insecticides but remains susceptible to organophosphates, providing useful information for possible future control.

Published
2019
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