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PNAS Papers on Myeloid Differentiation MicroRNAs, Urinary Exosomes, Maize Domestication

Editor's Note: Some of the articles described below are not yet available at the PNAS site but are scheduled to be posted this week.

Researchers from India and the US consider microRNA roles behind early stages of hematopoietic multipotent progenitor lineage commitment, focusing on the myeloid pathway leading to B and T lymphocyte immune cell development. With the help of miRNA profiling, Ago2-RIPSeq, and other approaches, the team highlights a handful of myeloid lineage gene-targeting miRNAs in early-stage B cells and T cells, including miR-186-5p, miR-128-3p, and miR-330-5p. The authors found that expression of these miRNAs led to reduced myeloid differentiation potential of such cells, while myeloid lineage-related transcripts tended to be de-repressed when they dialed down miRNA levels in knockdown experiments. "Upon activation, the miRNAs act hand-in-hand with lineage-specific factors to antagonize inappropriately expressed genes in order to block available cell-fate options, leading to establishment of lineage identity," the authors conclude, arguing that "this study establishes miRNAs as significant and non-redundant regulatory components of B and T lymphocyte developmental networks."

A Wenzhou Medical University-led team takes a look at nanoscale extracellular vesicles, or exosomes, in human urine. Based on their RNA sequencing experiments, differentially expressed gene analyses, single-cell RNA sequencing data analyses, and other experiments, the researchers found that bladder tissue-specific genes are often expressed in urinary exosomes, producing expression features that were distinct from their subsequent analyses on samples collected from individuals with bladder cancer or kidney cancer. "Tracking the differentially expressed genes of cancers and corresponding enrichment analysis show urine exosomes are intensively involved in immune activities," the authors note, "indicating that they may be harnessed as reliable biomarkers of non-invasive liquid biopsy in cancer genomic diagnostics and precision medicine."

Investigators at the University of Wisconsin at Madison and elsewhere retrace genetic architecture changes marking the transition from a teosinte progenitor plant to maize during the crop's domestication trajectory. Using quantitative genetic analyses, the team assessed several teosinte and maize landrace populations from four sites in Mexico, along with thousands of progeny from each plant, uncovering genetic architecture and variation profiles that teosinte and maize have distinct genetic architecture, though that architecture appeared to be conserved within populations of each plant were largely conserved. "Our results suggest that while selection drove changes in essentially all traits between teosinte and maize," the authors say, "selection is far less important for explaining domestication trait differences among populations within teosinte or maize."