Biology subjects

Beimdiek, J.

Publications and source records attributed to Beimdiek, J..

3 recordsLinked to original sources

bioRxiv2023

Targeting the glycan epitope type I N-acetyllactosamine enables immunodepletion of human pluripotent stem cells from early differentiated cells

Cell surface biomarkers are fundamental for specific characterization of human pluripotent stem cells (hPSCs). Importantly, they can be applied for hPSC enrichment and/or purification but also to remove potentially teratoma-forming hPSCs from differentiated populations before clinical application. Several specific markers for hPSCs are glycoconjugates comprising the glycosphingolipid (GSL)-based glycans SSEA-3 and SSEA-4. We applied an analytical approach based on multiplexed capillary gel electrophoresis coupled to laser-induced fluorescence detection to quantitatively assess the GSL glycome of human embryonic stem cells and human induced pluripotent stem cells as well as during early stages of differentiation into mesoderm, endoderm, and ectoderm. Thereby, we identified the GSL lacto-N-tetraosylceramide (Lc4-Cer, Gal{beta}1-3GlcNAc{beta}1-3Gal{beta}1-4Glc-Cer), which comprises a terminal type 1 LacNAc (T1LN) structure (Gal{beta}1-3GlcNAc), to be rapidly decreased upon onset of differentiation. Using a specific antibody, we could confirm a decline of T1LN-terminating glycans during the first four days of differentiation by live-cell staining and subsequent flow cytometry. We could further separate T1LN-positive and T1LN-negative cells out of a mixed population of pluripotent and differentiated cells by magnetic activated cell sorting. Notably, not only the T1LN-positive but also the T1LN-negative population was positive for SSEA-3, SSEA-4, and SSEA-5 while expression of nuclear pluripotency markers OCT4 and NANOG was highly reduced in the T1LN-negative population, exclusively. Our findings suggest T1LN as a pluripotent stem cell-specific glycan epitope that is more rapidly down-regulated upon differentiation than SSEA-3, SSEA-4, and SSEA-5.

cell biology↗

bioRxiv2023

Neolactotetraosylceramide: A novel non-invasive urinary biomarker for bladder cancer

There is an urgent need to identify noninvasive biomarkers for bladder cancer. Here, we applied glycan analytics by multiplex capillary gel electrophoresis coupled to laser-induced fluorescence detection (xCGE-LIF) to unravel the global glycosphingolipid (GSL)-glycan profile of primary tumor tissues and urine samples from bladder cancer patients. Thereby, we detected neolactotetraosylceramide (Gal{beta}1-4GlcNAc{beta}1-3Gal{beta}1-4Glc-Cer, nLc4) at significantly increased levels from tumorigenic regions of bladder tissues compared to non-malignant adjacent material (n = 30). Specific expression of nLc4 in cancer tissue was confirmed by immunofluorescence staining. GSL-glycan profiling by xCGE-LIF of urinary exosomes showed that nLc4 is increased in bladder cancer patients (n = 16) when compared to controls (n = 50), with an overall sensitivity of 57% and specificity of 90%. We set-up an ELISA targeting nLc4-containing urinary exosomes from bladder cancer patients (n = 9) and cancer-free individuals (n = 9) demonstrating an overall sensitivity and specificity of 89% and 78%, respectively. SIGNFICANCEThis study shows that levels of nLc4 are significantly elevated in bladder cancer tissue and urinary exosomes of bladder cancer patients. Urinary detection of nLc4 by glycan analytics or ELISA outperforms standard diagnostic modalities, facilitating noninvasive bladder cancer diagnosis. Furthermore, nLc4 bears the potential of being a target for bladder cancer therapy.

cancer biology↗

bioRxiv2022

The monosialoganglioside GM1a protects trophoblasts, erythrocytes and endothelial cells against complement attack

The complement system is a part of the innate immune system in the fluid phase and efficiently eliminates pathogens. However, its activation requires tight regulation on the host cell surface in order not to compromise cellular viability. Previously, we showed that loss of placental cell surface sialylation in mice in vivo leads to a maternal complement attack at the fetal-maternal interface, ultimately resulting in loss of pregnancy. To gain insight into the regulatory function of sialylation in complement activation, we here generated trophoblast stem cells devoid of sialylation, which also revealed complement sensitivity and cell death in vitro. Glycolipid-analysis by xCGE-LIF allowed us to identify the monosialoganglioside GM1a as a key element of cell surface complement regulation. Exogenously administered GM1a integrated into the plasma membrane of trophoblasts, dramatically increased binding of complement factor H and was sufficient to protect the cells from complement attack and cell death. Furthermore, GM1a treatment rescued sensitized human erythrocytes and endothelial cells from complement attack in a concentration dependent manner. This study demonstrates for the first time the complement regulatory potential of exogenously administered gangliosides and paves the way for sialoglycotherapeutics as a novel substance class for membrane-targeted complement regulators. Key pointsO_LIThe naturally occurring sialic acid containing glycosphingolipid GM1a is a potent regulator of complement activation on mammalian trophoblast, erythrocyte and endothelial cell surfaces. C_LIO_LIIncorporated GM1a recruits complement factor H and thus could represent a novel membrane-targeted complement therapeutic. C_LI

biochemistry↗