Impaired DNA damage responses are associated with several diseases, including pregnancy complications. Recent research identified an ATM-kinase dependent function for the nuclear isoform of the receptor for advanced glycation end-products (RAGE) during double strand break (DSB)-repair. RAGE contributes to end-resectioning of broken DNA sites by binding with the MRE11-Rad50-Nbs1 (MRN) complex. Placental research is limited regarding the impact of genomic instability and the mechanism for potential repair. We tested the hypothesis regarding the involvement of RAGE during the repair of placental DNA-DSBs. We first identified that the pregnancy complications of PE and preterm labor (PTL) experience loss of genomic integrity and an in vitro trophoblast cell model was used to characterize trophoblast DSBs. Colocalized immunofluorescence of γ-H2AX and RAGE support the potential involvement of RAGE in cellular responses to DNA-DSBs. Immunoblotting for both molecules in PE and PTL placenta samples and in trophoblast cells validated a connection. Co-immunoprecipitation studies revealed interactions between RAGE and pATM and MRE11 during DNA-DSBs. Reduced cellular invasion confirmed the role of genomic instability in trophoblastic function. Collectively, these experiments identified genomic instability in pregnancy complications, the impact of defective DNA on trophoblast function, and a possible RAGE-mediated mechanism during DNA-DSB repair.

Inflammation underpins pulmonary disease progression during tobacco smoke exposure that may culminate in irreversdible pulmonary remodeling. While primary smoke poses notable risk, nearly half of the US population is also at risk due to exposure to secondhand smoke (SHS). In the present study, we assessed a potential role for RAGE, a cell‐surface pattern recognition receptor implicated in pro‐inflammatory signaling, following exposure to SHS. Specifically, we used wild type, RAGE null, and lung‐specific RAGE overexpressing transgenic (TG) mice and evaluated the elaboration of inflammatory mediators in bronchoalveolar lavage fluid (BALF). Select mice were administered semi‐synthetic glycosaminoglycan ethers (SAGEs), a family of anionic, partially lipophilic sulfated polysaccharide derivatives known to inhibit RAGE signaling. Mice were exposed to room air (RA) or SHS from three Kentucky 3R4F research cigarettes via a nose‐only delivery system (Sireq Scientific, Montreal, Canada) five days a week and ip injections of PBS or SAGE (a 30mg/kg body weight) occurred three times per week from PN40 until sacrifice date on PN70. RAGE mRNA and protein expression was elevated in wild type and TG mice following SHS exposure and no expression was detected in RAGE nulls. BALF analyses revealed RAGE‐mediated control of leukocyte extravasation and a multiplex cytokine array confirmed a role for RAGE in the coordination of pro‐inflammatory chemokine/cytokine secretion. Among other mediators, TNF‐a, MIP‐2, and IL‐1b were each differentially secreted by lung tissue following SHS exposure and concentrations were significantly decreased in BALF from exposed RAGE null or wild type mice concomitantly administered SAGEs. In summary, inflammatory responses induced by SHS exposure were influenced by the availability of RAGE, as evidenced by RAGE nulls and SAGE treatment. These data reveal fascinating data suggesting the utility of RAGE abrogation in lessening smoke‐induced pulmonary exacerbations.

Receptors for advanced glycation end‐products (RAGE) are multi‐ligand cell surface receptors of the immunoglobin superfamily prominently expressed by lung epithelium. Previous experiments demonstrate that over‐expression of RAGE by murine alveolar epithelium throughout embryonic development causes neonatal lethality coincident with significant lung hypoplasia. In the current study, we evaluated the expression of TTF‐1, a homeodomain‐containing transcription factor critical for branching morphogeneis, in mice that differentially expressed RAGE. We also contexualized TTF‐1 expression with the abundance of FoxA2, a winged double helix DNA binding protein that influences respiratory epithelial cell differentiation, and surfactant proteins. Conditional RAGE over‐expression was induced in mice throughout gestation (embryonic day (E)0‐18.5) as well as during the critical saccular period (E15.5‐18.5) of development and analyses were conducted on E18.5 lung tissue. Histology revealed marked loss of lung tissue beginning in the canalicular stage of lung development and continuing throughout the saccular period. We discovered consistently decreased expression for both TTF‐1 and FoxA2 in lungs from TG mice compared to age‐matched controls. We also clarified diminished surfactant protein abundance in TG mice, suggesting possible hindered differentiation and/or proliferation of alveolar epithelial cells under the genetic control of these two critical transcription factors. These results demonstrate that RAGE must be specifically regulated during lung formation and that perturbation of epithelial cell differentiation culminating in respiratory distress and perinatal lethality may coincide with elevated RAGE expression in the lung parenchyma.