Jing Wang

Organoid technology, as an innovative approach, has shown great potential in disease modeling, target screening, and the development of treatment strategies. However, traditional organoids still have three major limitations in research: the absence of specific cell types, the lack of blood–brain barrier structure, and insufficient reproducibility of experimental results. In recent years, researchers have gradually overcome these limitations by introducing innovative techniques such as advanced culture methods, microfluidic systems, bioprinting, organoid transplantation, and assembloid construction. This progress has facilitated the widespread application of organoids in the study of neurodegenerative diseases. This paper aims to systematically review the technological innovations of organoids in the study of neurodegenerative diseases. By summarizing classical organoid construction strategies and their limitations, it emphasizes the value of organoids in comprehensive applications within neurodegenerative disease research. In this review, we focus on five specific neurodegenerative diseases: Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, amyotrophic lateral sclerosis, and frontotemporal dementia. Research in these diseases demonstrates that organoids improve experimental accessibility and reduce development cycles in disease modeling, target discovery, and therapeutic strategy formation. Using customized equipment and gene editing techniques, these organoids can be tailored to specific needs, providing pathophysiologically relevant disease models and enhancing our understanding of neurodegenerative diseases. Although organoid technology has demonstrated significant advantages in disease research, its potential for treating neurodegenerative diseases has not yet been fully explored, which may become an important direction for future research.

Background: Circumferential pulmonary vein isolation (CPVI) plus left atrial low‐voltage areas (LVA) modification is a useful method to treat paroxysmal atrial fibrillation (PAF); however, it is hard to predict LVA burden before the procedure. The existence of chronic kidney disease (CKD) increases the prevalence of left atrial LVA. In this study, we explored the relationship between renal function and the LVA burden in elderly patients with PAF. Methods: We retrospectively analyzed the 435 elderly patients with PAF who underwent ablation. Based on the LVA burden measured during the procedure, the patients were divided into four groups: Group 1 (LVA burden ≤ 5%, n = 356), Group 2 (LVA burden 5%–10%, n = 39), Group 3 (LVA burden 10%–15%, n = 16), and Group 4 (LVA burden > 15%, n = 24). Results: Increasing LVA burden was associated with a progressive decline in eGFR. A significant difference was observed between Group 1 and Group 4 (86.6 ± 12.9 vs. 76.4 ± 17.7, p = 0.003). eGFR was identified to be a predictor for LVA burden > 10%, with the optimal cut‐off value for GFR being 75.7 mL/min/1.73 m ² , having a sensitivity of 54.2% and specificity of 80.4%. Conclusions: A lower eGFR is associated with higher LVA burden in elderly patients with PAF.

Studies have shown that protein phosphorylation plays an important role in morphine abuse. However, the neurobiological mechanism of protein phosphatase 2A (PP2A) underlying the morphine-priming process is still unclear. Here we constructed T29–2-Cre; PP2A^fl/fl conditional knockout mice (KO) and investigated the role of hippocampal PP2A in morphine priming. We observed that the deficit of PP2A inhibited the priming behavior of morphine and blocked the priming-induced long-term potentiation (LTP) in the hippocampus of KO mice. Moreover, the expression levels of Rack1 and the membrane GluN2B were significantly reduced in the nucleus accumbens of KO mice compared with those in the control mice, which may be attributed to the decreased HDAC4 in the hippocampus of KO mice. Consistent with it, the similar inhibited priming effects were also observed in the wild-type mice treated with sodium butyrate (NaB)—a nonspecific inhibitor of histone deacetylases—3 h after morphine administration. Taken together, our results suggest that hippocampal PP2A may be involved in morphine priming through the PP2A/HDAC4/Rack1 pathway.

Currently, more and more patients suffer from peripheral nerve injury due to trauma, tumor and other causes worldwide. Biomaterial-based nerve conduits are increasingly recognized as a potential alternative to nerve autografts for the treatment of peripheral nerve injury. However, an ideal nerve conduit must offer topological guidance and biochemical and electrical signal transduction mechanisms. In this work, aligned conductive nanofibrous scaffolds comprising polylactic-co-glycolic acid and multiwalled carbon nanotubes (MWCNTs) were fabricated via coaxial electrospinning, and nerve growth factor (NGF) and Lycium barbarum polysaccharides (LBP) purified from the wolfberry were loaded on the core and shell layers of the nanofibers, respectively. LBP were confirmed to accelerate long-distance axon regeneration after severe peripheral nerve injury. In addition, the synergistic promotion of LBP and NGF on nerve cell proliferation and neurite outgrowth was demonstrated. MWCNTs were introduced into the aligned fibers to further increase the electrical conductivity, which promoted the directional growth and neurite extension of neurons in vitro. Further, the combination of conductive fibrous scaffolds with electrical stimulation that mimics endogenous electric fields significantly promoted the differentiation of PC12 cells and the axon outgrowth of neurons. Based on robust cell-induced behaviors, conductive composite fibers with optimized fiber alignment may be used for the promotion of nerve recovery.

Protein phosphorylation plays an important role in learning and memory. Protein phosphatase 2A (PP2A) is a serine/threonine phosphatase involved in the regulation of neural synaptic plasticity. Here, to determine if PP2A is necessary for successful learning and memory, we have utilized a Tg (Camk2a-cre) T29–2Stl mice to specific knock down the expression of hippocampal PP2A in mice. By analysing behavioural, we observed that loss of PP2A in the hippocampal CA1 area did not affect the formation of memory but impaired contextual fear memory extinction. We use the electrophysiological recording to find the synaptic mechanisms. The results showed that the basic synapse transmission and synaptic plasticity of PP2A conditional knockout (CKO) mice were impaired. Moreover, PP2A CKO mice exhibited a saturating long-term potentiation inducted by strong theta burst stimulation but no depotentiation after low-frequency stimulation. Taken together, our results provide the evidence that PP2A is involved in synaptic transmission and hippocampus-dependent memory extinction.

WD repeat protein 1 (Wdr1), known as a cofactor of actin-depolymerizing factor (ADF)/cofilin, is conserved among eukaryotes, and it plays a critical role in the dynamic reorganization of the actin cytoskeleton. However, the function of Wdr1 in the central nervous system remains elusive. Using Wdr1 conditional knockout mice, we demonstrated that Wdr1 plays a significant role in regulating synaptic plasticity and memory. The knockout mice exhibited altered reversal spatial learning and fear responses. Moreover, the Wdr1 CKO mice showed significant abnormalities in spine morphology and synaptic function, including enhanced hippocampal long-term potentiation and impaired long-term depression. Furthermore, we observed that Wdr1 deficiency perturbed actin rearrangement through regulation of the ADF/cofilin activity. Taken together, these results indicate that Wdr1 in the hippocampal CA1 area plays a critical role in actin dynamics in associative learning and postsynaptic receptor availability.

Depression is a devastating psychiatric disorder widely attributed to deficient monoaminergic signaling in the central nervous system. However, most clinical antidepressants enhance monoaminergic neurotransmission with little delay but require 4–8 weeks to reach therapeutic efficacy, a paradox suggesting that the monoaminergic hypothesis of depression is an oversimplification. In contrast to the antidepressants targeting the monoaminergic system, a single dose of the N-methyl-D-aspartate receptor (NMDAR) antagonist ketamine produces rapid (within 2 h) and sustained (over 7 days) antidepressant efficacy in treatment-resistant patients. Glutamatergic transmission mediated by NMDARs is critical for experience-dependent synaptic plasticity and learning, processes that can be modified indirectly by the monoaminergic system. To better understand the mechanisms of action of the new antidepressants like ketamine, we review and compare the monoaminergic and glutamatergic antidepressants, with emphasis on neural plasticity. The pathogenesis of depression may involve maladaptive neural plasticity in glutamatergic circuits that may serve as a new class of targets to produce rapid antidepressant effects.