2025-10-15 大阪大学微生物病研究所
図1非閉塞性無精子症(NOA)モデルの治療戦略
NOAモデルマウスの精巣にLNPを用いてmRNAを補充し、精子形成を進行させ、顕微授精を行い、産仔を獲得した。
<関連情報>
- https://www.biken.osaka-u.ac.jp/achievement/research/2025/249
- https://www.biken.osaka-u.ac.jp/_files/_ck/files/researchtopics/2025/2025MashikoIkawa_PNAS_v7.pdf
- https://www.pnas.org/doi/10.1073/pnas.2516573122
脂質ナノ粒子を用いた精巣mRNA送達による非閉塞性無精子症マウスモデルにおける精子および子孫の生産 Sperm and offspring production in a nonobstructive azoospermia mouse model via testicular mRNA delivery using lipid nanoparticles
Daisuke Mashiko, Chihiro Emori, Yuki Hatanaka, +4 , and Masahito Ikawa
Proceedings of the National Academy of Sciences Published:October 13, 2025
DOI:https://doi.org/10.1073/pnas.2516573122
Significance
Nonobstructive azoospermia (NOA) caused by genetic defects in meiotic genes remains untreatable, as no curative therapies exist for patients lacking male haploid germ cells. Here, we demonstrate that lipid nanoparticle (LNP)-mediated mRNA delivery targeting the testis-specific gene Pdha2 restores spermatogenesis in this NOA mouse model. This intervention enabled the production of viable offspring via intracytoplasmic sperm injection. Unlike viral vectors, LNPs provide a safe, nonintegrating strategy for transient gene expression in testicular tissue. Our findings establish a foundation for mRNA-based gene restoration therapy for genetically defined NOA and offer a therapeutic concept for treating human male infertility of genetic origin.
Abstract
Microsurgical testicular sperm extraction (microTESE) with intracytoplasmic sperm injection (ICSI) represents the current standard treatment for nonobstructive azoospermia (NOA). However, cures remain unavailable for NOA patients lacking retrievable haploid cells. mRNA supplementation could be a potential treatment for genetic defects leading to impaired spermatogenesis. Lipid nanoparticles (LNPs) have emerged as mRNA delivery vehicles with minimal risk of genome integration; however, their ability to selectively deliver mRNA to specific cell types remains limited. To overcome this, microRNA (miRNA) target sequences were incorporated into mRNA constructs to restrict expression specifically to germ cells. Using pyruvate dehydrogenase E1 subunit alpha 2 (PDHA2) knockout mice as an NOA model with meiotic arrest, we demonstrate that LNP-mediated delivery of Pdha2 mRNA enables the resumption and completion of meiosis, restores sperm production, and facilitates the generation of healthy fertile offspring via ICSI. Whole-genome sequencing of the offspring confirmed the absence of large-scale genomic abnormalities. Our results provide proof of concept for a safe and effective chemically synthesized LNP-based mRNA therapy with miRNA-regulated germ cell specificity, offering a promising therapeutic approach to treating male infertility caused by spermatogenesis arrest.
