Biology subjects

Szepanowski, L.-P.

Publications and source records attributed to Szepanowski, L.-P..

3 recordsLinked to original sources

bioRxiv2024

Investigating BPDE-induced embryonic toxicity employing hiPSC-based models

Benzo[a]pyrene diol epoxide (BPDE) is a metabolite of the environmental contaminant Benzo[a]pyrene- a byproduct of incomplete combustion of organic matter. BPDE reacts with DNA to form BPDE-DNA bulky adducts which if not removed can lead to mutations due to DNA base-pair substitutions. While the effects of BPDE on somatic cells are fairly well described, its effects on early human development are currently unknown. In this study, we investigated for the first time the effect of BPDE on human induced pluripotent stem cells (hiPSCs) and their differentiated neuroprogenitor cells (NPCs) as a model for early embryonic development. Furthermore, we compared hiPSCs and NPCs derived from cells of patients suffering from Nijmegen Breakage Syndrome (NBS), which is a chromosomal instability disorder characterized by defective DNA repair and increased risk of malignancies. Transcriptome analysis, coupled with protein content analysis employing immunostaining and Western blots, revealed that hiPSCs are more sensitive to BPDE exposure when compared to NPCs with an enhanced expression of several genes associated with p53-mediated DNA damage response, including DNA repair by lesion bypass, cell cycle checkpoints and extrinsic apoptosis. We also identified that cells from NBS patients showed less apoptotic response and a distinct p53 response than their healthy counterparts. This iPSC-based study enhances our meagre knowledge of the effects of BPDE on early human development in both healthy individuals and NBS patients. Furthermore, our model conforms with the 3Rs principle.

pharmacology and toxicology↗

bioRxiv2024

Hemozoin induces Malaria via activation of DNA damage, p38 MAPK and Neurodegenerative Pathways in Human iPSC-derived Neuronal Model of Cerebral Malaria

Malaria caused by Plasmodium falciparum infection results in severe complications including cerebral malaria (CM), in which approximately 30% of patients end up with neurological sequelae. Sparse in vitro cell culture-based experimental models which recapitulate the molecular basis of CM in humans has impeded progress in our understanding of its etiology. This study employed healthy human induced pluripotent stem cells (iPSCs) derived neuronal cultures stimulated with hemozoin (HMZ)-the malarial toxin as a model for CM. Secretome, qRT-PCR, Metascape, and KEGG pathway analyses were conducted to assess elevated proteins, genes, and pathways. Neuronal cultures treated with HMZ showed enhanced secretion of interferon-gamma (IFN-{gamma}), interleukin (IL)1-beta (IL-1{beta}), IL-8 and IL-16. Enrichment analysis revealed malaria, positive regulation of cytokine production and positive regulation of mitogen-activated protein kinase (MAPK) cascade which confirm inflammatory response to HMZ exposure. KEGG assessment revealed up-regulation of malaria, MAPK and neurodegenerative diseases-associated pathways which corroborates findings from previous studies. Additionally, HMZ induced DNA damage in neurons. This study has unveiled that exposure of neuronal cultures to HMZ, activates molecules and pathways similar to that observed in CM and neurodegenerative diseases. Furthermore, our model is an alternative to rodent experimental models of CM.

neuroscience↗

bioRxiv2023

Cockayne syndrome patient iPSC-derived brain organoids and neurospheres show early transcriptional dysregulation of biological processes associated with brain development and metabolism.

Cockayne syndrome is a rare hereditary autosomal recessive disorder characterized by diverse neurological afflictions. However, little is known about the cerebral development in CS patients. We generated neurospheres and cerebral organoids utilizing Cockayne Syndrome B Protein (CSB) deficient induced pluripotent stem cells derived from two patients with distinct severity levels of CS and healthy controls. The transcriptome of both developmental timepoints was explored using RNA-Seq and bioinformatic analysis to identify dysregulated biological processes common to both CS patients in comparison to control. CSB-deficient neurospheres displayed upregulation of VEGFA-VEGFR2 signaling pathway, Vesicle-Mediated transport and head development. CSB-deficient cerebral organoids exhibited downregulation of brain development, neuron projection development and synaptic signalling. We further identified upregulation of Steroid Biosynthesis as common to both timepoints, in particular upregulation of the Cholesterol Biosynthesis branch. Our results provide insights into the neurodevelopmental dysregulation in CS patients and strengthen the theory, that CS is not only a neurodegenerative, but also a neurodevelopmental disorder.

neuroscience↗