Objectives: This study aimed to establish a transgenic mouse model expressing nucleus-localized human α-synuclein (α-syn) to investigate its impact on the central nervous system and behavior and the underlying mechanisms involved. Methods: A nuclear localization sequence (NLS) was added to the end of the human SNCA (hSNCA) gene. Subsequently, an empty vector and a mammalian lentiviral vector of the hSNCA-NLS were constructed. Transgenic mice were generated via microinjection, with genotyping and protein expression confirmed by PCR and western blotting. Only male mice were used in subsequent behavioral and molecular experiments. Immunofluorescence identified the colocalization of human α-syn with the cell nucleus in mouse brain tissues. Behavioral changes in transgenic mice were assessed using open field, rotarod, and O-maze tests. qPCR and Western blotting detected expression levels of genes and proteins related to inflammation, endoplasmic reticulum stress (ERS), and apoptosis. Bulk RNA sequencing was used to screen for differentially expressed genes and signaling pathways. Results: We successfully constructed a transgenic mouse model expressing human α-syn. Human α-syn was widely expressed in the heart, liver, spleen, kidneys, and brain of the mice, with distinct nuclear localization observed. Behavioral assessments demonstrated that, by 2 months of age, the mice exhibited motor dysfunction alongside astrocyte proliferation and neuroinflammation. At 6 months, the elevated expression of ERS-related genes (ATF6, PERK, and IRE1) and activation of the PERK-Beclin1-LC3II pathway indicated progressive ERS. By 9 months, apoptotic events had occurred, accompanied by significant anxiety-like behaviors. Bulk RNA sequencing further identified key differentially expressed genes, including IL-1α, TNF, PERK, BECLIN, GABA, IL-6α, P53, LC3II, NOS, and SPAG, suggesting their involvement in the observed pathological and behavioral phenotypes. Conclusions: The nuclear localization human α-syn transgenic mice were successfully established. These findings demonstrate that nucleus-localized α-syn induces early motor deficits, which are likely mediated by neuroinflammation, whereas later anxiety-like behaviors may result from ERS-induced apoptosis. This model provides a valuable tool for elucidating the role of nuclear α-syn in Parkinson’s disease and supports further mechanistic and therapeutic research.

The use of cynomolgus monkeys ( Macaca fascicularis ) has facilitated the establishment of gene-modified animal models, and the appropriate number of high-quality mature oocytes (MII-stage oocytes) are crucial in assisted reproductive technologies (ART) of cynomolgus macaques. In this study we performed 3 different superovulation protocols on 24 female cynomolgus monkeys aimed to improve the proportion of MII-stage oocyte retrieval. The results suggested some differences in the proportion of MII-stage oocytes between the personalized superovulation protocol and the superovulation protocols I and II. Afterwards, we performed Intracytoplasmic sperm injection (ICSI) on 22 MII-stage oocytes derived from one animal with personalized superovulation protocol, obtained 15 embryos of 2-4-cells, 2 cases of successful pregnancy after transferring to 4 surrogate female, and obtained 3 aborted fetuses. These results suggested that personalized superovulation protocol incorporated the menstrual cycle length of each cynomolgus monkey, and the timing of oocytes retrieval based on the equation: menstrual cycle length/2 ± 1, which increased the rate of MII-stage oocytes acquired and generation of cynomolgus monkeys embryos with ICSI based on these oocytes, and finally could successfully develop into fetus under conditions that effectively guarantee the synchronization of the surrogate mothers. SUMMARY STATEMENT: The personalized superovulation protocol based on the menstrual cycle length of each cynomolgus monkey can increase the rate of MII-stage oocytes acquired, and finally could successfully develop into fetus under conditions that minimize damage to the surrogate mothers and effectively guarantee the synchronization of the surrogate mothers.