Exploring Transcriptomic Landscapes in Red Blood Cells, in Their Extracellular Vesicles and on a Single-Cell Level

Area of Science:

• Hematology
• Molecular Biology
• Genomics

Background:

• Red blood cells (RBCs), despite lacking typical transcriptomes due to enucleation, contain small amounts of diverse long transcripts and microRNAs.
• The precise function and significance of these RNAs within RBCs remain largely undetermined.
• Extracellular vesicles (EVs) shed by RBCs are crucial for maintaining cellular homeostasis by removing cytoplasmic content.

Purpose of the Study:

• To investigate the transcriptomes of RBCs and their shed EVs using advanced sequencing techniques.
• To explore the presence and characteristics of RNA within RBC subpopulations.
• To elucidate the potential role of RBC-derived EVs in intercellular communication.

Main Methods:

• Next-generation sequencing (NGS) to analyze RBC and EV transcriptomes.
• Single-cell RNA sequencing (scRNA-seq) to identify RBC subpopulations and their RNA content.
• Quantitative PCR (qPCR) and imaging flow cytometry to validate findings in reticulocytes.

Main Results:

• scRNA-seq revealed approximately 10% of RBCs possess detectable mRNA, forming three distinct subpopulations with varying mRNA levels and globin/ribosomal gene expression.
• Metastasis Associated Lung Adenocarcinoma Transcript 1 (MALAT1), a long non-coding RNA, was highly enriched in one RBC subpopulation.
• The RBC transcriptome, including MALAT1, was found within their EVs, suggesting a mechanism for intercellular RNA transfer.

Conclusions:

• RBCs harbor a complex transcriptome, with distinct subpopulations exhibiting unique RNA profiles.
• The long non-coding RNA MALAT1 is a notable component of specific RBC subpopulations.
• RBC-derived EVs carry transcripts, indicating their potential role in mediating intercellular communication within the bloodstream.