Reduced NO levels and activity are signs of endothelial dysfunction, which is important in mediating BP changes. Previously, we demonstrated that transient receptor potential channel V4 (TRPV4) could form a functional complex with other proteins to mediate vasodilation in endothelial cells (ECs). But how TRPV4 interacts with the NO pathway in larger arteries requires further exploration.
We used single-cell RNA-sequencing to find the CD106+ TRPV4high NOS3high ECs. The TRPV4-eNOS interaction was verified by co-immunoprecipitation and immuno-FRET, and their binding site was found by site-directed mutagenesis. Endothelium-specific TRPV4 knockout (TRPV4EC-/- ) mice were used to study the effect of the TRPV4-eNOS interaction on BP. A small molecule, JNc-463, was designed through molecular docking technology.
We uncovered CD106+ TRPV4high NOS3high ECs in the mouse aorta, which could regulate vasodilation via a TRPV4-eNOS interaction, and were essential to regulate BP. The TRPV4-eNOS interaction markedly decreased during the process of hypertension. We further attempted to identify molecules involved in the TRPV4-eNOS interaction and developed a small-molecule drug, JNc-463, which could increase the TRPV4-eNOS interaction to enhance vasodilation and exert antihypertensive effects in mice.
This is the first study integrating single-cell RNA-Seq, single-cell functional study and drug screening in aorta. We identified a subpopulation of CD106+ TRPV4high NOS3high ECs, in which an impaired TRPV4-eNOS interaction was important in the progress of hypertension, and we designed a small molecule, JNc-463, to improve the impaired TRPV4-eNOS interaction in hypertension.
© 2021 The British Pharmacological Society.

The Dnmt2 enzyme utilizes the catalytic mechanism of eukaryotic DNA methyltransferases to methylate several tRNAs at cytosine 38. Dnmt2 mutant mice, flies, and plants were reported to be viable and fertile, and the biological function of Dnmt2 has remained elusive. Here, we show that endochondral ossification is delayed in newborn Dnmt2-deficient mice, which is accompanied by a reduction of the haematopoietic stem and progenitor cell population and a cell-autonomous defect in their differentiation. RNA bisulfite sequencing revealed that Dnmt2 methylates C38 of tRNA Asp(GTC), Gly(GCC), and Val(AAC), thus preventing tRNA fragmentation. Proteomic analyses from primary bone marrow cells uncovered systematic differences in protein expression that are due to specific codon mistranslation by tRNAs lacking Dnmt2-dependent methylation. Our observations demonstrate that Dnmt2 plays an important role in haematopoiesis and define a novel function of C38 tRNA methylation in the discrimination of near-cognate codons, thereby ensuring accurate polypeptide synthesis.
© 2015 The Authors. Published under the terms of the CC BY NC ND 4.0 license.