Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by a rapid accumulation of amyloid β (Aβ) protein in the hippocampus, which impairs synaptic structures and neuronal signal transmission, induces neuronal loss, and diminishes memory and cognitive functions. The present study investigated the impact of neuregulin 1 (NRG1)-ErbB4 signaling on the impairment of neural networks underlying hippocampal long-term potentiation (LTP) in 5xFAD mice, a model of AD with greater symptom severity than that of TG2576 mice. Specifically, we observed parvalbumin (PV)-containing hippocampal interneurons, the effect of NRG1 on hippocampal LTP, and the functioning of learning and memory. We found a significant decrease in the number of PV interneurons in 11-month-old 5xFAD mice. Moreover, synaptic transmission in the 5xFAD mice decreased at 6 months of age. The 11-month-old transgenic AD mice showed fewer inhibitory PV neurons and impaired NRG1-ErbB4 signaling than did wild-type mice, indicating that the former exhibit the impairment of neuronal networks underlying LTP in the hippocampal Schaffer-collateral pathway. In conclusion, this study confirmed the impaired LTP in 5xFAD mice and its association with aberrant NRG1-ErbB signaling in the neuronal network.

Background: Cerebrospinal fluid (CSF) amyloid-β _1-42 (Aβ _1-42 ), total tau protein (t-Tau), and phosphorylated Tau (p-Tau) are ATN biomarkers for Alzheimer’s disease (AD) and reflect pathogenic changes in the brain. CSF biomarkers of AD are considered for inclusion in the diagnostic criteria for research and clinical purposes to reduce the uncertainty of clinical diagnosis and to distinguish among AD stages. Objective: This study aims to compare two commercially available analytical platforms with respect to accuracy and the potential for early diagnosis of AD. Methods: A total of 211 CSF samples from healthy control (HC) and AD subjects were analyzed using two analytical platforms, INNOTEST ELISA and INNOBIA AlzBio3 xMAP kits. The accuracy of diagnosis and AUC values distinguishing study groups were compared between the two analytical platforms. Results: The absolute values for Aβ _1-42 , t-Tau, and p-Tau ₁₈₁ levels differed between the two platforms. The Aβ _1-42 levels decreased, while t-Tau and p-Tau levels increased according to the AD stages. The AUC of Aβ _1-42 and t-Tau, which distinguish the early stages of AD (preclinical and prodromal AD), were similar between the two platforms, whereas there were significant differences in p-Tau AUC values. CSF p-Tau using the INNOBIA was highly accurate for distinguishing both preclinical AD (AUC = 0.826, cut-off score≥38.89) and prodromal AD (AUC = 0.862, cut-off score≥41.88) from HC. Conclusion: The accuracy of CSF p-Tau levels in the preclinical and prodromal AD is higher for the INNOBIA than the INNOTEST, and the early stage AD can be accurately distinguished from HC.