Citation

  • Authors: Idowu TO. et al.
  • Year: 2021
  • Journal: Intensive Care Med Exp 9 38
  • Applications: in vivo / DNA / in vivo-jetPEI

Method

Following the manufacturer's guidelines, in vivo-jetPEI transfection reagent was used as a carrier to overexpress GATA3 in murine pulmonary vasculature transiently. Mice were injected by a single blinded investigator retroorbitally with 40 μg control or GATA3 plasmid DNA (LZRS-GATA3) complexed with in vivo-jetPIE at an N/P ratio of 8 in 200 μl of 5% glucose solution. 24 h after injection, ECs were isolated for RNA and protein expression analysis or hypotension was induced for further studies.

Abstract

Background: Reduced endothelial Tie2 expression occurs in diverse experimental models of critical illness, and experimental Tie2 suppression is sufficient to increase spontaneous vascular permeability. Looking for a common denominator among different critical illnesses that could drive the same Tie2 suppressive (thereby leak inducing) phenotype, we identified "circulatory shock" as a shared feature and postulated a flow-dependency of Tie2 gene expression in a GATA3 dependent manner. Here, we analyzed if this mechanism of flow-regulation of gene expression exists in vivo in the absence of inflammation. Results: To experimentally mimic a shock-like situation, we developed a murine model of clonidine-induced hypotension by targeting a reduced mean arterial pressure (MAP) of approximately 50% over 4 h. We found that hypotension-induced reduction of flow in the absence of confounding disease factors (i.e., inflammation, injury, among others) is sufficient to suppress GATA3 and Tie2 transcription. Conditional endothelial-specific GATA3 knockdown (B6-Gata3tm1-Jfz VE-Cadherin(PAC)-cerERT2) led to baseline Tie2 suppression inducing spontaneous vascular leak. On the contrary, the transient overexpression of GATA3 in the pulmonary endothelium (jet-PEI plasmid delivery platform) was sufficient to increase Tie2 at baseline and completely block its hypotension-induced acute drop. On the functional level, the Tie2 protection by GATA3 overexpression abrogated the development of pulmonary capillary leakage. Conclusions: The data suggest that the GATA3-Tie2 signaling pathway might play a pivotal role in controlling vascular barrier function and that it is affected in diverse critical illnesses with shock as a consequence of a flow-regulated gene response. Targeting this novel mechanism might offer therapeutic opportunities to treat vascular leakage of diverse etiologies.

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