Noninvasive characterization of Alzheimer's disease by circulating, cell-free messenger RNA next-generation sequencing.

The lack of accessible noninvasive tools to examine the molecular alterations occurring in the brain limits our understanding of the causes and progression of Alzheimer's disease (AD), as well as the identification of effective therapeutic strategies. Here, we conducted a comprehensive profiling of circulating, cell-free messenger RNA (cf-mRNA) in plasma of 126 patients with AD and 116 healthy controls of similar age. We identified 2591 dysregulated genes in the cf-mRNA of patients with AD, which are enriched in biological processes well known to be associated with AD. Dysregulated genes included brain-specific genes and resembled those identified to be dysregulated in postmortem AD brain tissue. Furthermore, we identified disease-relevant circulating gene transcripts that correlated with the severity of cognitive impairment. These data highlight the potential of high-throughput cf-mRNA sequencing to evaluate AD-related pathophysiological alterations in the brain, leading to precision healthcare solutions that could improve AD patient management.

Non-invasive characterization of human bone marrow stimulation and reconstitution by cell-free messenger RNA sequencing.

Circulating cell-free mRNA (cf-mRNA) holds great promise as a non-invasive diagnostic biomarker. However, cf-mRNA composition and its potential clinical applications remain largely unexplored. Here we show, using Next Generation Sequencing-based profiling, that cf-mRNA is enriched in transcripts derived from the bone marrow compared to circulating cells. Further, longitudinal studies involving bone marrow ablation followed by hematopoietic stem cell transplantation in multiple myeloma and acute myeloid leukemia patients indicate that cf-mRNA levels reflect the transcriptional activity of bone marrow-resident hematopoietic lineages during bone marrow reconstitution. Mechanistically, stimulation of specific bone marrow cell populations in vivo using growth factor pharmacotherapy show that cf-mRNA reflects dynamic functional changes over time associated with cellular activity. Our results shed light on the biology of the circulating transcriptome and highlight the potential utility of cf-mRNA to non-invasively monitor bone marrow involved pathologies.