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Identification of common sequence motifs shared exclusively among selectively packed exosomal pathogenic microRNAs

Jiani Bei1, Yuan Qiu1, Diane Cockrell2

  • 1Department of Pathology, University of Texas Medical Branch, Galveston, Texas, USA.

Journal of Cellular Physiology
|June 19, 2023
PubMed

Insights

Rickettsia-infected endothelial cell exosomes (R-ECExos) disrupt microvascular endothelial cell barriers. Specific microRNAs (miRNAs) like miR23a and miR30b are selectively enriched in R-ECExos, driving this barrier dysfunction.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Pathogen-Host Interactions

Background:

  • Spotted fever rickettsioses are increasing, causing severe disease by affecting brain and lung tissues.
  • Rickettsia-infected endothelial cell-derived exosomes (R-ECExos) have been previously shown to contain specific microRNAs (miRNAs).
  • The mechanism by which R-ECExos induce barrier dysfunction in recipient microvascular endothelial cells (MECs) remains unclear.

Purpose of the Study:

  • To investigate the molecular mechanism of R-ECExos-induced barrier dysfunction in recipient MECs.
  • To determine the role of exosomal RNA cargo in mediating R-ECExos effects.
  • To identify specific miRNAs enriched in R-ECExos and their potential sorting mechanisms.

Main Methods:

  • Treatment of recipient pulmonary MECs (PMECs) with R-ECExos derived from Rickettsia parkeri-infected human dermal MECs.
  • Assessment of VE-cadherin expression and paracellular barrier function in recipient PMECs.
  • Quantification of miRNA levels in parent MECs and R-ECExos.
  • Bioinformatic analysis of miRNA sequences to identify common motifs.

Main Results:

  • R-ECExos treatment disrupted VE-cadherin and compromised barrier function in recipient PMECs.
  • Barrier dysfunction was dependent on the exosomal RNA content of R-ECExos.
  • The microvasculopathy-relevant miR23a-27a-24 cluster and miR30b were selectively enriched in R-ECExos.
  • No significant difference in miRNA levels was observed in parent dermal MECs post-infection.
  • Common sequence motifs (ACA, UCA, CAG) were identified among the selectively enriched exosomal miRNAs.

Conclusions:

  • R-ECExos selectively enrich specific miRNAs, including the miR23a-27a-24 cluster and miR30b.
  • These enriched miRNAs contribute to R-ECExos-induced microvascular endothelial cell barrier dysfunction.
  • Sequence motifs within these miRNAs likely play a role in their selective sorting into exosomes.
  • Further research is needed to elucidate the precise mechanisms of miRNA sorting and their functional consequences in rickettsial infections.
Keywords:
endothelial barrier dysfunctionexosomefluidic AFMmicroRNArickettsial infectionsequence motif

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