Biology subjects

Kemper, A.

Publications and source records attributed to Kemper, A..

4 recordsLinked to original sources

bioRxiv2026

Peripheral Monocyte-Derived Extracellular Vesicles Establish an Immune-Brain Communication Pathway in Alzheimer's Disease

Alzheimer's disease (AD) is increasingly recognized as a systemic disorder involving both central and peripheral immune dysfunction, yet the mechanisms by which peripheral immune cells influence neurodegeneration remain poorly understood. Here we identify a physiological extracellular vesicle (EV)-mediated route through which peripheral monocytes communicate with neurons and show that AD-associated monocyte remodeling converts this pathway into a mechanism that mediates neuronal injury. Reanalysis of single-cell transcriptomic data revealed pronounced inflammatory and EV-related transcriptional remodeling in circulating monocytes from patients with AD. Using a genetic CD63-based EV tracking mouse, we found that EVs released from peripheral Lyz2-expressing myeloid cells, including monocytes, accessed the healthy brain parenchyma and preferentially associated with neurons. EVs isolated from primary peripheral monocytes of 5xFAD mice were enriched in inflammatory cargo, including IL-1{beta}, and markedly suppressed distal axonal growth. Neutralization of EV-associated IL-1{beta} partially restored axonal growth, identifying IL-1{beta} as an important mediator of EV-induced neuronal injury. A{beta} stimulation reproduced key features of this pathogenic EV phenotype in RAW 264.7 macrophage-like cells and induced coordinated metabolic dysfunction and pro-inflammatory activation in primary peripheral monocytes. Moreover, repeated systemic administration of EVs from A{beta}-stimulated RAW 264.7 cells accelerated behavioral and cognitive decline and reduced hippocampal synaptic integrity in 5xFAD mice without increasing cerebral amyloid plaque burden. Together, these findings reveal a peripheral monocyte-EV-neuron communication axis that operates under homeostatic conditions and can be redirected toward pathogenic signaling in AD. Targeting this EV-mediated pathway may provide a therapeutic strategy complementary to current A{beta}-directed approaches.

neuroscience↗

bioRxiv2025

Engineered Extracellular Vesicles Enriched with miR-214 Enhance the Efficacy of Chemotherapy for Ovarian Cancer

Recurrent ovarian cancer (OC) remains a major cause of mortality due to chemoresistance and metastasis. Epigenetic dysfunction, particularly through altered microRNA (miRNA) expression, contributes to disease progression. Targeting these molecular aberrations is critical to prevent recurrence, limit metastasis and improve patient outcomes. Here, we identify the miR-214-3p/miR-199a-5p cluster as a stage-associated, tumor-suppressive network that is lost in recurrent and chemoresistant OC, but can be restored using engineered small extracellular vesicles enriched with this cluster (m214-sEVs). Using a clinically relevant mouse model that mimics spontaneous OC relapse following first-line platinum-based chemotherapy, we showed that m214-sEVs were internalized by OC cells and the OC niche fibroblasts via clathrin-mediated endocytosis, resulting in the elevation of miR-214-3p/miR-199a-5p and the downregulation of chemoresistance-associated genes, including toll-like receptor 4 (TLR4), {beta}-catenin, and the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein YKT6. Moreover, secondary tumor-derived sEVs (t-sEVs) released by OC and niche cells that internalized m214-sEVs reduced pro-metastatic proteins, such as integrin {beta}1 and matrix metalloproteinase 9 (MMP9), in their cargo and limited their capacity to promote invasion and resistance. In vitro, YKT6 overexpression in ovarian cancer stem cells (OCSCs) attenuated the effect of m214-sEVs on sensitizing carboplatin to block OCSC migration. These findings demonstrate that engineered m214-sEVs designed to restore clinically lost tumor-suppressive miRNAs can concurrently reverse chemoresistance and reprogram tumor-derived EV communication by targeting oncogenic networks. Statement of SignificanceEngineered small extracellular vesicles delivering miR-214-3p/miR-199a-5p overcome chemoresistance and inhibit recurrence in ovarian cancer by targeting oncogenic networks and reprogramming tumor-derived extracellular vesicle communication within the tumor microenvironment.

cancer biology↗

bioRxiv2022

Patient-derived parathyroid organoids as tracer and drug-screening application model

Parathyroid diseases are characterized by dysregulation of calcium homeostasis and alterations in parathyroid hormone (PTH) excretion. The understanding of parathyroid hyperplastic growth and the development of parathyroid-targeted treatment and imaging tracers could benefit from in vitro models. Therefore, we aim to establish stem cell-derived, three-dimensional organoids representing human parathyroid tissue in vitro. Patient-derived hyperplastic parathyroid tissue was dispersed and parathyroid organoids (PTO) were cultured and characterized. PTO-derived cells were shown to exhibit in vitro self-renewal over several passages, indicative of the presence of putative stem cells. Immunofluorescence and RNA-sequencing confirm that PTO phenocopy hyperplastic parathyroid tissue. Exposure of PTO to increasing calcium concentrations and to PTH-lowering drugs resulted in a significantly reduced PTH excretion. Next to this, the PTO showed specific binding of 11C-methionine to the targeted receptor. Additionally, when organoids were incubated with 99mTc-sestamibi, we observed a higher uptake in PTOs from patients with a 99mTc-sestamibi positive scan compared to patients with a negative scan. These data show functionality of PTOs resembling the parathyroid. In conclusion, we present a patient-derived PTO culture, that recapitulates the originating tissue on gene and protein expression and functionality. This PTO model paves the way for future physiology studies and therapeutic target and tracer discovery.

cell biology↗

bioRxiv2019

High accuracy DNA sequencing on a small, scalable platform via electrical detection of single base incorporations

High throughput DNA sequencing technologies have undergone tremendous development over the past decade. Although optical detection-based sequencing has constituted the majority of data output, it requires a large capital investment and aggregation of samples to achieve optimal cost per sample. We have developed a novel electronic detection-based platform capable of accurately detecting single base incorporations. The GenapSys technology with its electronic detection modality allows the system to be compact, accessible, and affordable. We demonstrate the performance of the system by sequencing several different microbial genomes with varying GC content. The platform is capable of generating up to 2 Gb of high-quality nucleic acid sequence in a single run. We routinely generate sequence data that exceeds 99% raw accuracy with read lengths of up to 175 bp. Average quality scores remain above Q30 (99.9% raw sequencing accuracy) beyond 150 bp, with more than 85% of total bases at or above Q30. The utility of the platform is highlighted by targeted sequencing of the human genome. We show high concordance of SNP detection on the human NA12878 HapMap cell line with data generated on the Illumina sequencing platform. In addition, we sequenced a targeted panel of cancer-associated genes in a well characterized reference standard. With multiple library preparation approaches on this sample, we were able to identify low frequency mutations at expected allele frequencies.

genomics↗