PSEN1, PSEN2, and APP mutations cause Alzheimer's disease (AD) with an early age at onset (AAO) and progressive cognitive decline. PSEN1 mutations are more common and generally have an earlier AAO; however, certain PSEN1 mutations cause a later AAO, similar to those observed in PSEN2 and APP.
We examined whether common disease endotypes exist across these mutations with a later AAO (~ 55 years) using hiPSC-derived neurons from familial Alzheimer's disease (FAD) patients harboring mutations in PSEN1A79V, PSEN2N141I, and APPV717I and mechanistically characterized by integrating RNA-seq and ATAC-seq.
We identified common disease endotypes, such as dedifferentiation, dysregulation of synaptic signaling, repression of mitochondrial function and metabolism, and inflammation. We ascertained the master transcriptional regulators associated with these endotypes, including REST, ASCL1, and ZIC family members (activation), and NRF1 (repression).
FAD mutations share common regulatory changes within endotypes with varying severity, resulting in reversion to a less-differentiated state. The regulatory mechanisms described offer potential targets for therapeutic interventions.
© 2025. The Author(s).

Background: Mutations in PSEN1, PSEN2, and APP can lead to Alzheimer’s disease (AD) with an early age at onset (AAO) and hallmark progressive cognitive decline. These mutations are highly penetrant. Although mutations in PSEN1 are more common and usually have an earlier AAO, certain mutations in PSEN1 cause a later AAO, similar to PSEN2 and APP mutations. We sought to determine whether common disease endotypes exist across these mutations with a relatively late AAO. Methods We generated hiPSC-derived neurons from patients harboring autosomal-dominant, familial Alzheimer’s disease (FAD) mutations in PSEN1, PSEN2, and APP with a documented age at onset (AAO) around 55 years: PSEN1A79V, PSEN2N141I, and APPV717I. We carried out RNA-seq and ATAC-seq to mechanistically characterize the gene expression and chromatin accessibility changes, respectively. Differential expression analysis, enrichment analysis, TF activity identification, and co-expression module detection were performed for RNA-seq. Differential peak analysis and annotation, TF motif footprinting and differential motif accessibility, and peak functional enrichment were performed for ATAC-seq. This approach allowed us to identify the correlation between gene expression and chromatin accessibility associated with key disease endotypes. Results Using a multiomics approach, we identify and characterize common endotypes in mutations across all three FAD genes: dedifferentiation of a mature neuron to a less differentiated quasi-neuron state, dysregulation of synaptic signaling, repression of mitochondrial function and metabolism, and inflammation. The integrativeanalysis allowed us to ascertain the master transcriptional regulators associated with these endotypes, including REST, ASCL1, and ZIC family members (activation), as well as NRF1 (repression). Conclusions Our findings characterize the common regulatory changes within endotypes across these FAD mutations. However, the severity of dysregulation often differs between PSEN1, PSEN2, and APP mutations both in magnitude and direction. The overarching common link between mutations in FAD genes is the reversion to a less-differentiated neuron state. The transcriptional regulatory mechanisms described within disease endotypes offer potential targets for therapeutic interventions.

While amyloid-β (Aβ) plaques are considered a hallmark of Alzheimer's disease, clinical trials focused on targeting gamma secretase, an enzyme involved in aberrant Aβ peptide production, have not led to amelioration of AD symptoms or synaptic dysregulation. Screening strategies based on mechanistic, multi-omics approaches that go beyond pathological readouts can aid in the evaluation of therapeutics. Using early-onset Alzheimer's (EOFAD) disease patient lineage PSEN1A246E iPSC-derived neurons, we performed RNA-seq to characterize AD-associated endotypes, which are in turn used as a screening evaluation metric for two gamma secretase drugs, the inhibitor Semagacestat and the modulator BPN-15606. We demonstrate that drug treatment partially restores the neuronal state while concomitantly inhibiting cell cycle re-entry and dedifferentiation endotypes to different degrees depending on the mechanism of gamma secretase engagement. Our endotype-centric screening approach offers a new paradigm by which candidate AD therapeutics can be evaluated for their overall ability to reverse disease endotypes.
© 2022 The Authors. Alzheimer's & Dementia published by Wiley Periodicals LLC on behalf of Alzheimer's Association.

The generation of human stem cell-derived spheroids and organoids represents a major step in solving numerous medical, pharmacological, and biological challenges. Due to the advantages of three-dimensional (3D) cell culture systems and the diverse applications of human pluripotent stem cell (iPSC)-derived definitive endoderm (DE), we studied the influence of spheroid size and 3D cell culture systems on spheroid morphology and the effectiveness of DE differentiation as assessed by quantitative PCR (qPCR), flow cytometry, immunofluorescence, and computational modeling. Among the tested hydrogel-based 3D systems, we found that basement membrane extract (BME) hydrogel could not retain spheroid morphology due to dominant cell-matrix interactions. On the other hand, we found that nanofibrillar cellulose (NFC) hydrogel could maintain spheroid morphology but impeded growth factor diffusion, thereby negatively affecting cell differentiation. In contrast, suspension culture provided sufficient mass transfer and was demonstrated by protein expression assays, morphological analyses, and mathematical modeling to be superior to the hydrogel-based systems. In addition, we found that spheroid size was reversely correlated with the effectiveness of DE formation. However, spheroids of insufficient sizes failed to retain 3D morphology during differentiation in all the studied culture conditions. We hereby demonstrate how the properties of a chosen biomaterial influence the differentiation process and the importance of spheroid size control for successful human iPSC differentiation. Our study provides critical parametric information for the generation of human DE-derived, tissue-specific organoids in future studies.
Copyright © 2021 Bogacheva, Harjumäki, Flander, Taalas, Bystriakova, Yliperttula, Xiang, Leung and Lou.

Acute myeloid leukemia (AML) is a heterogenous group of disorders that emerge from the malignant transformation of hematopoietic stem cells. Chemokine stromal cell-derived factor 1(SDF-1) and its receptor CXC receptor 4 (CXCR4) has an essential role in dissemination of blast cells. Study aimed to detect CXCR4 expression and the SDF-1 (rs1801157) gene polymorphisms and correlate them with prognosis and outcome in AML patients.
The study was conducted on 60 de-novo AML patients, and 60 healthy controls. SDF-1 (rs1801157) gene polymorphisms were detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), and CXCR4 expression was done using flow cytometry analysis.
SDF-1 dominant model (AG+AA) had higher risk AML (p 0.002). CXCR4positive cases were associated significantly with toxic manifestations (p 0.019), lower CR rates (p 0.004), and unfavorable cytogenetics (p 0.027). Multivariate analysis showed that combined CXCR4positive with dominant SDF-1 considered as independent prognostic factor for shorter overall survival (OS) in AML patients (p 0.031).
SDF-1 dominant model had a higher risk to develop AML, and CXCR4 positive expression predicts poor prognosis in AML patients and it could represent a targeted therapy in AML. In addition, CXCR4 could be easily integrated into the initial routine diagnostic work up of AML..