GATA2 participates in the recanalization of lymphatic vessels after surgical lymph node extirpation

Perturbed collagen metabolism underlies lymphatic recanalization failure in Gata2 heterozygous deficient mice

Lymphedema has become a global health issue following the growing number of cancer surgeries. Curative or supportive therapeutics have long been awaited for this refractory condition. Transcription factor GATA2 is crucial in lymphatic development and maintenance, as GATA2 haploinsufficient disease often manifests as lymphedema. We recently demonstrated that Gata2 heterozygous deficient mice displayed delayed lymphatic recanalization upon lymph node resection. However, whether GATA2 contributes to lymphatic regeneration by functioning in the damaged lymph vessels' microenvironment remains explored. In this study, our integrated analysis demonstrated that dermal collagen fibers were more densely accumulated in the Gata2 heterozygous deficient mice. The collagen metabolism-related transcriptome was perturbed, and collagen matrix contractile activity was aberrantly increased in Gata2 heterozygous embryonic fibroblasts. Notably, soluble collagen placement ameliorated delayed lymphatic recanalization, presumably by modulating the stiffness of the extracellular matrix around the resection site of Gata2 heterozygous deficient mice. Our results provide valuable insights into mechanisms underlying GATA2-haploinsufficiency-mediated lymphedema and shed light on potential therapeutic avenues for this intractable disease.

miR-409-3p Regulated by GATA2 Promotes Cardiac Fibrosis through Targeting Gpd1

Cardiac fibrosis is a hallmark of numerous chronic cardiovascular diseases that leads to heart failure. However, there is no validated therapy for it. Dysregulation of microRNAs has been confirmed to be involved in cardiac fibrosis development. However, the regulatory network was not well explored. This study was the first to highlight the role and molecular mechanism of miR-409-3p in cardiac fibrosis. We found that miR-409-3p was consistently increased in three fibrotic models, including heart tissues of postmyocardial infarction (MI) mice and neonatal rat cardiac fibroblasts treated with angiotensin II (Ang II) or transforming growth factor-β (TGF-β). Furthermore, myocardial infarction surgery-induced cardiac fibrosis and dysfunction were attenuated by systemic delivery of miR-409-3p antagomir. Notably, transfection with miR-409-3p mimics promoted the proliferation of cardiac fibroblasts and fibroblast-to-myofibroblast differentiation, accompanied by upregulated expression of Col1a1, Col3a1, and α-SMA. On the contrary, the miR-409-3p inhibitor exhibited the opposite effect. Following this, we verified Gpd1 as a direct target of miR-409-3p. Gpd1 siRNA abolished the antifibrotic effect of miR-409-3p inhibitor in neonatal rat cardiac fibroblasts, suggesting that miR-409-3p promotes cardiac fibrosis at least partially through Gpd1. Moreover, GATA2 was identified as a cardiac fibrosis-associated upstream positive transcription factor of miR-409-3p. Finally, these findings suggest that modulating miR-409-3p could be a potential therapeutic method for cardiac fibrosis.