Premium
αENaC gene silencing by RNA interference (RNAi) attenuates lung fluid absorption in newborn rats
Author(s) -
Li Tianbo,
Hunley Charles,
Folkesson Hans G.
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a1340-a
Subject(s) - epithelial sodium channel , gene silencing , rna interference , lung , transfection , in vivo , fetus , medicine , messenger rna , ex vivo , andrology , endocrinology , biology , chemistry , gene , rna , sodium , pregnancy , biochemistry , organic chemistry , genetics , microbiology and biotechnology
In our studies, we used our recently developed RNAi technique to silence αENaC in newborn rat lungs in vivo by trans‐thoracic intrapulmonary siRNA‐generating pDNA injection. Newborn rats were removed from timed‐pregnant rats within 1 h after birth and immediately used for experiments. Twenty‐four hours after the trans‐thoracic intrapulmonary siRNA‐generating pDNA injection against αENaC ( pSi‐4 ), αENaC mRNA and protein levels were both reduced by ~80%, while βENaC and α 1 ‐Na,K‐ATPase expression did not change. As a functional endpoint we measured extravascular lung water ( EVLW ) and mortality. After αENaC silencing, EVLW was significantly increased and mortality was increased five‐fold. This suggested that the majority of newborn lung fluid absorption was ENaC dependent. We then confirmed these observations in isolated fetal distal lung epithelial ( FDLE ) cells. FDLE cells were isolated on gestation day 21 fetuses, transfection was done 1 day later, and αENaC expression was measured 24 h after transfection. This protocol mimicked the time points when newborn rats were transfected in vivo . Similar results were observed in the FDLE cells as in vivo . Thus, we provide convincing evidence that αENaC is involved in the transition from lung fluid secretion to lung fluid absorption at birth in the rat. ( Funded by March of Dimes Birth Defects Foundation Research Grant No. 6‐FY03‐64 )