Single cell transcriptomics identifies focal segmental glomerulosclerosis remission endothelial biomarker.

Area of Science:

• Nephrology
• Genomics
• Molecular Biology

Background:

• Kidney diseases involve complex cellular mechanisms.
• Understanding cellular processes is crucial for kidney function and failure research.
• The Kidney Precision Medicine Project (KPMP) aims to map kidney cell functions.

Purpose of the Study:

• Establish a single-cell RNA sequencing strategy for kidney biopsies.
• Define molecular subtypes within glomerular diseases.
• Investigate endothelial cell phenotypes in kidney diseases.

Main Methods:

• Utilized single-cell RNA sequencing on adult human kidney reference tissue.
• Applied unbiased clustering to identify 31 distinct cell clusters.
• Employed in silico and in situ hybridization to characterize endothelial cell phenotypes.
• Analyzed glomerular endothelial cell (GEC) transcripts in patient cohorts (NEPTUNE, ERCB).

Main Results:

• Successfully generated 22,268 single-cell profiles passing quality control.
• Identified 31 distinct cell clusters, annotated with specific cell markers.
• Characterized 3 endothelial cell clusters corresponding to distinct renal vascular beds.
• Observed highest GEC scores in patients with focal segmental glomerulosclerosis (FSGS).
• Discovered two distinct FSGS patient subgroups based on molecular endothelial signatures, with alpha-2 macroglobulin (A2M) as a key mediator.
• Found that glomerular A2M transcript levels correlated with lower proteinuria remission rates in FSGS patients.

Conclusions:

• Single-cell RNA sequencing effectively defines molecular subtypes in glomerular diseases.
• Endothelial cell phenotypes and their molecular signatures are critical in FSGS.
• Glomerular A2M expression is a potential biomarker linking endothelial function to long-term outcomes in FSGS.