Hanseul Park

The apolipoprotein E4 (APOE4) allele is the strongest genetic risk factor for sporadic Alzheimer's disease (AD), driving Aβ accumulation, tau pathology, and synaptic dysfunction. Allele‐specific correction of APOE4 represents a promising therapeutic strategy to mitigate disease progression. In this study, we developed an APOE4‐specific prime editing strategy based on an optimized APOE4‐targeting pegRNA, enabling precise and efficient conversion of the APOE4 allele to the lower‐risk APOE3 variant. We found that PE7 targeting the APOE4 allele achieved robust and specific editing without detectable off‐target effects. This correction reduced ApoE4 protein levels and attenuated key AD‐related pathologies, including Aβ42 accumulation, tau phosphorylation, and activation of the ERK1/2 pathway in APP/APOE4 knock‐in (KI) mice. Notably, PE7 treatment enhanced neuronal survival and improved cognitive performance in these mice. Furthermore, in human induced neurons derived from APOE3/4 heterozygous AD patient fibroblasts, PE7 consistently corrected the APOE4 allele and suppressed both amyloid‐ and tau‐associated pathologies. These findings establish PE7‐mediated APOE4 correction as a precise and efficient therapeutic genome‐editing strategy with translational potential for sporadic AD.

Mitochondrial redox homeostasis is a critical regulatory mechanism governing oocyte maturation and early embryonic development by mediating cellular energy metabolism and signaling cascades. However, under in vitro culture conditions, oxidative stress increases markedly, and excessive accumulation of mitochondrial oxidative species disrupts this balance, leading to mitochondrial membrane depolarization, reduced adenosine triphosphate production, and activation of apoptotic pathways. Such redox imbalance is a major factor compromising oocyte competence and embryonic developmental potential during in vitro embryo production (IVEP). This study aimed to investigate the effects of the mitochondria-targeted antioxidant 10-(6′-plastoquinonyl)-decyltriphenylphosphonium (SkQ1) on mitochondrial redox regulation, functional stability, and developmental competence during porcine in vitro maturation (IVM). Supplementation of the IVM medium with SkQ1 improved the redox status of oocytes and embryos, maintained mitochondrial membrane potential, and attenuated mitochondrial oxidative stress indicators. Oocytes treated with SkQ1 exhibited more synchronized nuclear and cytoplasmic maturation, and subsequent embryo development progressed more efficiently following fertilization. Furthermore, the expression of antioxidant- and mitochondrial biogenesis–related genes increased, while apoptotic activity was attenuated in the 0.2 μM SkQ1-treated group. Notably, distinct cell type–specific signaling responses to mitochondrial redox modulation were observed during IVEP: cumulus cells primarily activated mitochondrial biogenesis and quality-control pathways, oocytes preserved mitochondrial functional stability, and blastocysts displayed enhanced mitochondrial dynamics. These findings suggest that SkQ1 modulates mitochondrial activity through cell–stage–specific regulatory mechanisms throughout development. In conclusion, SkQ1 directly targets mitochondria to mitigate oxidative challenges and maintain cellular energy homeostasis, thereby promoting the oocyte-to-embryo transition. This study identifies mitochondrial redox modulation as a key determinant of porcine oocyte developmental competence and highlights SkQ1 as a promising regulator for optimizing mitochondrial integrity and developmental quality under IVEP conditions.

Metallothionein 3 (Mt3) is crucial for cellular homeostasis and neuroprotection, with accumulating evidence linking it to amyloid‐beta (Aβ) clearance by astrocytes. This study developed a CRISPR activator (CRISPRa) system using lipid nanoparticles to selectively upregulate Mt3 in astrocytes, aiming to enhance Aβ endocytosis in an Alzheimer's disease (AD) mouse model. To directly assess the therapeutic potential of Mt3 activation in a specific brain region, stereotaxic injection is utilized to deliver the CRISPRa lipid nanocomplexes. This approach enabled precise in vivo brain delivery and Mt3 activation. The findings reveal that CRISPRa lipid nanocomplex‐mediated Mt3 upregulation significantly boosts Aβ uptake by astrocytes, leading to a marked reduction in Aβ plaque accumulation in AD mouse brains. These results highlight CRISPRa lipid nanocomplex‐mediated Mt3 targeting as a promising strategy to enhance endogenous Aβ clearance, presenting a novel therapeutic avenue for AD.

Sporadic Alzheimer’s disease (sAD) is marked by dysregulated lipid metabolism, prominently involving apolipoprotein E (ApoE). MicroRNA-33 (miR-33) has emerged as a key regulator of lipid homeostasis, yet its role in sAD remains unclear. This study investigated miR-33 dysregulation in APOE ε4 allele (ApoE4)-associated sAD and explored its therapeutic potential using clustered regulatory interspaced short palindromic repeats (CRISPR)-mediated gene editing. Elevated miR-33 expression was observed in both AD patients, particularly those with ApoE4-associated sAD, and in the ApoE4 mouse model, implicating its role in AD pathology. Using CRISPR/Cas9, we modulated miR-33 expression in astrocytes to regulate ApoE lipidation and ameliorate AD-related pathology. Our results show that targeted miR-33 regulation in astrocytes via CRISPR/Cas9 restores ApoE lipidation and mitigates AD pathology in both in vitro and in vivo AD mice. Additionally, applying this gene therapy approach in ApoE4 sAD patient cell lines highlights its translational potential for therapeutic intervention. In conclusion, our findings elucidate miR-33’s role in AD pathogenesis and underscore the therapeutic promise of CRISPR-mediated miR-33 targeting for restoring lipid homeostasis and ameliorating AD pathology. This study provides valuable insights into developing miRNA-based gene therapy strategies for treating sAD.

Background/Objectives: Chronic stress disrupts neurochemical balance, triggers inflammation, and compromises neuronal integrity, contributing to the development of stress-related disorders. This study aimed to evaluate the preventative effects of Tremella fuciformis Berk (TF) enzymatic extracts on chronic restraint stress (CRS)-induced behavioral, neurochemical, and inflammatory dysfunctions in mice. Methods: Male C57BL/6N mice were administered TF at doses of 50 mg/kg and 100 mg/kg daily via oral gavage for 21 days during CRS exposure. Behavioral assessments, including anxiety and depression-like behavior tests, were conducted. Neurochemical and inflammatory markers were analyzed using PCR and ELISA, while histological examinations of hippocampal regions were performed to assess neuronal integrity. In vitro assays evaluated neuronal cell viability, protection against corticosterone (CORT)-induced cytotoxicity, and inhibition of monoamine oxidase (MAO) activity. Results: TF supplementation alleviated CRS-induced weight loss, normalized serum CORT levels, increased locomotor activity, reduced immobility time, and decreased anxiety-like behaviors. TF upregulated brain-derived neurotrophic factor (BDNF) mRNA, downregulated pro-inflammatory markers (CXCL2, iNOS, IFNG), and mitigated neuronal apoptosis in the hippocampus. In vitro, TF improved neuronal cell viability, protected against CORT-induced cytotoxicity, and significantly inhibited MAO activity, particularly MAO-A. Conclusions: These findings demonstrate the neuroprotective and anti-stress effects of Tremella fuciformis Berk enzymatic extracts, supporting its potential as a natural therapeutic intervention for stress-related disorders.

Background: Cathepsin D (Ctsd) has emerged as a promising therapeutic target for Alzheimer's disease (AD) due to its role in degrading intracellular amyloid beta (Aβ). Enhancing Ctsd activity could reduce Aβ42 accumulation and restore the Aβ42/40 ratio, offering a potential AD treatment strategy.

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by autoantibody production by hyper-activated B cells. Although mesenchymal stem cells (MSCs) relieve lupus symptoms by inhibiting mainly T cells, whether MSCs also inhibit B cells has been controversial. Here, we found that naïve MSCs inhibited IFN-γ production by T cells, but not IgM production by B cells. We used a chemical approach to prime MSCs to inhibit B cells. We found that ingenol-3-angelate (I3A), a non-tumor-promoting phorbol ester, activated MSCs to inhibit B cells in a TGF-β1-dependent manner. We also showed that IL-1β induced MSCs to continuously secrete TGF-β1, which directly inhibited IgM production by B cells, whereas IL-1β did not. I3A-treated MSCs were better than naïve MSCs at ameliorating SLE symptoms in MRL.fas^lpr mice. In summary, our data provide information on how to generate MSCs that are effective for the treatment of SLE characterized by excessive B cell activation.

κ-Carrageenan is a sulfated polysaccharide from red seaweed with substantial antioxidant activities. This study aimed to investigate the effect of κ-Carrageenan treatment on frozen–thawed (FT) porcine semen quality. Therefore, the spermatozoa were diluted and cryopreserved in a freezing extender supplemented with 0 (control), 0.2, 0.4, 0.6, and 0.8 mg/mL κ-Carrageenan. Sperm kinematics were assessed immediately after thawing (AT) and post-incubation for 120 min. The viability, acrosome integrity, lipid peroxidation, mitochondrial membrane potential (MMP), and intracellular caspase activity were measured AT. The results indicated that 0.2 mg/mL κ-Carrageenan increased total and progressive motility AT and post-incubation for 120 min (p < 0.05). Moreover, the viable sperm percentage and MMP after 0.2 mg/mL treatment were higher than those after control and other κ-Carrageenan concentration treatments. The proportion of acrosome-intact spermatozoa was significantly higher after 0.2 and 0.4 mg/mL κ-Carrageenan treatment than that after control and other κ-Carrageenan concentration treatments. The intracellular caspase activity was not significantly different among the experimental groups. However, the MDA concentration after 0.2 mg/mL κ-Carrageenan treatment was lower (p < 0.05) than that after the control treatment. Taken together, adding κ-Carrageenan to the porcine semen freezing extender improved the FT sperm quality mainly by influencing membrane stability and protecting against oxidative stress.