Frayne, J. | Search bioRxiv

bioRxiv2022

Human cellular model systems of β-thalassemia enablein-depth analysis of disease phenotype

{beta}-thalassemia is a prevalent genetic disorder causing severe anemia due to defective erythropoiesis, with few treatment options. Studying the underlying molecular defects is impeded by paucity of suitable patient material. In this study we created human disease cellular model systems for {beta}-thalassemia, which accurately recapitulate the phenotype of patient erythroid cells. We also developed a high throughput compatible fluorometric-based assay for evaluating severity of disease phenotype and utilised the assay to demonstrate positive response of lines to verified reagents, providing validation for such applications. TMT-based comparative proteomics confirmed the same profile of proteins previously reported, whilst providing new insights into the altered molecular mechanisms in {beta}-thalassemia erythroid cells, with upregulation of a wide range of biological pathways and processes observed. Overall, the lines provide a sustainable supply of disease cells as novel research tools, for identifying new therapeutic targets, and as screening platforms for novel drugs and therapeutic reagents.

cell biology↗

bioRxiv2018

Stable knockout and complementation of receptor expression using in vitro cell line derived reticulocytes for dissection of host malaria invasion requirements

Invasion of and intracellular development within the red blood cell by malaria parasites requires interaction with a multitude of host proteins expressed at the surface of or inside the cell. Perhaps the biggest obstacle to dissection of specific functions of host proteins during invasion is the inability to manipulate protein expression in the genetically intractable anucleate red blood cell. Whilst genetic manipulation and subsequent in vitro differentiation of nucleated erythroid precursors have facilitated progress in this area, such approaches are limited by the finite proliferative capacity of primary hematopoietic stem cells, and a failure of erythroleukemic cell lines to enucleate, respectively. Here, we report that reticulocytes derived through in vitro differentiation of an enucleation competent immortalized erythroblast cell line (BEL-A) support both successful invasion and growth by Plasmodium falciparum. Using CRISPR-mediated gene knockout and lentiviral expression of open reading frames, we validate an essential role for the erythrocyte receptor basigin in P. falciparum invasion and, for the first time, demonstrate that this can be rescued by re-expression of the receptor or of a mutant thereof. Specifically, using sustainable edited clones derived from this line, we exclude a functional role for the cytoplasmic domain of basigin during invasion, and challenge the reported requirement of its associated receptor cyclophilin B. These data establish the use of reticulocytes derived from immortalized erythroblasts as a crucial model system to explore specific hypotheses regarding host receptor requirements and involvement in P. falciparum invasion.

cell biology↗