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Programmed cell death-1 (PD-1) is an immunoinhibitory receptor required to suppress inappropriate immune responses such as autoimmunity. Immune checkpoint antibodies that augment the PD-1 pathway lead to immune-related adverse events (irAEs), organ non-specific side effects due to autoimmune activation in humans. In this study, we generated a PD-1 mutant pig using electroporation-mediated introduction of the CRISPR/Cas9 system into porcine zygotes to evaluate the PD-1 gene deficiency phenotype. We optimized the efficient guide RNAs (gRNAs) targeting PD-1 in zygotes and transferred electroporated embryos with the optimized gRNAs and Cas9 into recipient gilts. One recipient gilt became pregnant and gave birth to two piglets. Sequencing analysis revealed that both piglets were biallelic mutants. At 18 mo of age, one pig showed non-purulent arthritis of the left elbow/knee joint and oligozoospermia, presumably related to PD-1 modification. Although this study has a limitation because of the small number of cases, our phenotypic analysis of PD-1 modification in pigs will provide significant insight into human medicine and PD-1-deficient pigs can be beneficial models for studying human irAEs., (© 2024. The Society for In Vitro Biology.)

We evaluated the quality and fertilizing ability of frozen-thawed porcine sperm that were selected using a commercially available device (MIGLIS, Menicon Life Science) consisting of three parts: an outer lid, an inner lid, and a tube. Firstly, to determine an adequate concentration of caffeine for separation, frozen-thawed sperm were incubated with different concentrations of caffeine (0, 1, 2.5, 5, and 10 mM) in a MIGLIS device. To determine the appropriate incubation time for separating sperm in the MIGLIS device, frozen-thawed sperm were incubated with 2.5 mM caffeine for 5, 10, 15, or 20 min. To evaluate the fertilization and embryo development of oocytes fertilized with frozen-thawed sperm separated into two regions (outer and inner) in the MIGLIS device, the separated sperm from the three boars was used to fertilize in vitro-matured oocytes and cultured in vitro for 7 days. Sperm quality parameters of sperm collected from the inner tube after incubation with 2.5 mM caffeine were superior to sperm incubated without caffeine. Moreover, sperm collected from the inner tube after incubation for 10 min had a higher progressive motility. The rate of blastocyst produced from spermatozoa collected from the inner tube after incubation with 2.5 mM caffeine for 10 min significantly increased compared to that produced from spermatozoa from the outer tube, regardless of the boar. In conclusion, sperm sorting using the MIGLIS device may be useful for separating high-quality sperm after incubation with 2.5 mM caffeine for 10 min to improve blastocyst formation., (© 2024 Wiley‐VCH GmbH. Published by John Wiley & Sons Ltd.)

Sterilization of the culture medium using ultraviolet (UV)‐C reduces the potential adverse effects of microorganisms and allows for long‐term use. In the present study, we investigated the effects of a medium directly irradiated with UV‐C prior to in vitro culture on the development and quality of porcine in vitro‐fertilized embryos and the free amino acid composition of the culture media. The culture media (porcine zygote medium [PZM‐5] and porcine blastocyst medium [PBM]) were irradiated with UV‐C at 228 and 260 nm for 1 and 3 days, respectively. Next, the culture media were irradiated with UV‐C at 228 nm for 3, 7, or 14 days. After in vitro fertilization, the embryos were cultured in the UV‐C‐irradiated media for 7 days. Free amino acid levels in culture media irradiated with 228 and 260 nm UV‐C for 3 days were analysed. The blastocyst formation rate of embryos cultured in media irradiated with 260 nm UV‐C for 3 days was significantly lower than that of embryos cultured in non‐irradiated control media. However, 228 nm UV‐C irradiation for up to 14 days did not affect blastocyst formation rates and quality in the resulting blastocysts. Moreover, 260 nm UV‐C irradiation significantly increased the taurine concentration in both culture media and decreased methionine concentration in the PBM. In conclusion, UV‐C irradiation at 228 nm before in vitro culture had no detrimental effects on embryonic development. However, 260 nm UV‐C irradiation decreased embryo development and altered the composition of free amino acids in the medium. [ABSTRACT FROM AUTHOR]