Title:	Spatial characterization of bone microenvironment in relation to human aging: a graph analysis.
DNr:	NAISS 2023/22-675
Project Type:	NAISS Small Compute
Principal Investigator:	Pablo Emiliano Gomez Ruiz <emiliano.gomez@physics.gu.se>
Affiliation:	Göteborgs universitet
Duration:	2023-06-27 – 2024-07-01
Classification:	10604
Homepage:	http://braph.org/
Keywords:

Abstract

The current understanding of human bone pathology and its marrow spatial organization largely relies and suffers from laborious 2D sectioning and under-sampling of tissue. Here we developed a tissue-clearing approach for multiplexed 3D visualization and quantification of mRNAs and proteins in human bones. Muliplexed mRNA profiling of 380,000 osteocytes revealed a drastic loss of Romosozumab targeted SOST-expressing cells and increased spatial dispersion with age. Combining RNA-protein probing to unsupervised 3D graph learning reveals increasing prevalence of avasculars CXCL12(mRNA)-expressing stromal cells (CAR cells) and their patterned microenvironment with age. Applying scRNA-seq analysis to DeepBone suggests avascular human CAR stroma were enriched with JUND- signature. Further profiling of CD271+ and CD146+ CAR cell subsets revealed these two populations of skeletal stem and progenitor cells occupy distinct trabecular and arteriolar niches while sharing an Endoglin+ sinusoidal environment that degenerates with age. Therefore our work provides the first comprehensive spatial characterization of changing bone microenvironment in relation to human aging. The graph analysis of the project aims to uncover motifs in the graph structure of cells. It is a collaboration of teams in Sahlgrenska Hospital, Gothenburg University, and Karolinska Institutet. The samples are obtained using the light sheet technique at the Soft-matter Lab in Gothenburg University.