Synthesis and characterization of PNA oligomers containing preQ1 as a positively charged guanine analogue.

We report the synthesis of a peptide nucleic acid (PNA) monomer containing preQ1, a positively charged guanine analogue. The new monomer was incorporated into PNA oligomers using standard Fmoc-chemistry-based solid-phase synthesis. The preQ1 unit-containing PNA oligomers exhibited improved affinity for their complementary DNA through electrostatic attraction, and their sequence specificity was not compromised. It could be beneficial to incorporate preQ1 into PNA oligomers instead of guanine when creating antisense/antigene agents or research tools.

FOXO1 regulates developmental lymphangiogenesis by upregulating CXCR4 in the mouse-tail dermis.

Lymphangiogenesis plays important roles in normal fetal development and postnatal growth. However, its molecular regulation remains unclear. Here, we have examined the function of forkhead box protein O1 (FOXO1) transcription factor, a known angiogenic factor, in developmental dermal lymphangiogenesis using endothelial cell-specific FOXO1-deficient mice. FOXO1-deficient mice showed disconnected and dilated lymphatic vessels accompanied with increased proliferation and decreased apoptosis in the lymphatic capillaries. Comprehensive DNA microarray analysis of the causes of in vivo phenotypes in FOXO1-deficient mice revealed that the gene encoding C-X-C chemokine receptor 4 (CXCR4) was the most drastically downregulated in FOXO1-deficient primary lymphatic endothelial cells (LECs). CXCR4 was expressed in developing dermal lymphatic capillaries in wild-type mice but not in FOXO1-deficient dermal lymphatic capillaries. Furthermore, FOXO1 suppression impaired migration toward the exogenous CXCR4 ligand, C-X-C chemokine ligand 12 (CXCL12), and coordinated proliferation in LECs. These results suggest that FOXO1 serves an essential role in normal developmental lymphangiogenesis by promoting LEC migration toward CXCL12 and by regulating their proliferative activity. This study provides valuable insights into the molecular mechanisms underlying developmental lymphangiogenesis.

Transcription factor FOXO1 promotes cell migration toward exogenous ATP via controlling P2Y1 receptor expression in lymphatic endothelial cells.

Sprouting migration of lymphatic endothelial cell (LEC) is a pivotal step in lymphangiogenic process. However, its molecular mechanism remains unclear including effective migratory attractants. Meanwhile, forkhead transcription factor FOXO1 highly expresses in LEC nuclei, but its significance in LEC migratory activity has not been researched. In this study, we investigated function of FOXO1 transcription factor associated with LEC migration toward exogenous ATP which has recently gathered attentions as a cell migratory attractant. The transwell membrane assay indicated that LECs migrated toward exogenous ATP, which was impaired by FOXO1 knockdown. RT-PCR analysis showed that P2Y1, a purinergic receptor, expression was markedly reduced by FOXO1 knockdown in LECs. Moreover, P2Y1 blockage impaired LEC migration toward exogenous ATP. Western blot analysis revealed that Akt phosphorylation contributed to FOXO1-dependent LEC migration toward exogenous ATP and its blockage affected LEC migratory activity. Furthermore, luciferase reporter assay and ChIP assay suggested that FOXO1 directly bound to a conserved binding site in P2RY1 promoter and regulated its activity. These results indicated that FOXO1 serves a pivotal role in LEC migration toward exogenous ATP via direct transcriptional regulation of P2Y1 receptor.