The pentose phosphate pathway mediates hyperoxia-induced lung vascular dysgenesis and alveolar simplification in neonates
Jiannan Gong, Zihang Feng, Abigail L. Peterson, Jennifer F. Carr, Xuexin Lu, Haifeng Zhao, Xiangming Ji, You-Yang Zhao, Monique E. De Paepe, Phyllis A. Dennery, Hongwei Yao
Jiannan Gong, Zihang Feng, Abigail L. Peterson, Jennifer F. Carr, Xuexin Lu, Haifeng Zhao, Xiangming Ji, You-Yang Zhao, Monique E. De Paepe, Phyllis A. Dennery, Hongwei Yao
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Research Article Pulmonology

The pentose phosphate pathway mediates hyperoxia-induced lung vascular dysgenesis and alveolar simplification in neonates

Abstract

Dysmorphic pulmonary vascular growth and abnormal endothelial cell (EC) proliferation are paradoxically observed in premature infants with bronchopulmonary dysplasia (BPD), despite vascular pruning. The pentose phosphate pathway (PPP), a metabolic pathway parallel to glycolysis, generates NADPH as a reducing equivalent and ribose 5-phosphate for nucleotide synthesis. It is unknown whether hyperoxia, a known mediator of BPD in rodent models, alters glycolysis and the PPP in lung ECs. We hypothesized that hyperoxia increases glycolysis and the PPP, resulting in abnormal EC proliferation and dysmorphic angiogenesis in neonatal mice. To test this hypothesis, lung ECs and newborn mice were exposed to hyperoxia and allowed to recover in air. Hyperoxia increased glycolysis and the PPP. Increased PPP, but not glycolysis, caused hyperoxia-induced abnormal EC proliferation. Blocking the PPP reduced hyperoxia-induced glucose–derived deoxynucleotide synthesis in cultured ECs. In neonatal mice, hyperoxia-induced abnormal EC proliferation, dysmorphic angiogenesis, and alveolar simplification were augmented by nanoparticle-mediated endothelial overexpression of phosphogluconate dehydrogenase, the second enzyme in the PPP. These effects were attenuated by inhibitors of the PPP. Neonatal hyperoxia augments the PPP, causing abnormal lung EC proliferation, dysmorphic vascular development, and alveolar simplification. These observations provide mechanisms and potential metabolic targets to prevent BPD-associated vascular dysgenesis.

Authors

Jiannan Gong, Zihang Feng, Abigail L. Peterson, Jennifer F. Carr, Xuexin Lu, Haifeng Zhao, Xiangming Ji, You-Yang Zhao, Monique E. De Paepe, Phyllis A. Dennery, Hongwei Yao

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Figure 3

Blocking the PPP reduces hyperoxia-induced proliferation in cultured lung ECs.

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Blocking the PPP reduces hyperoxia-induced proliferation in cultured lun...
(A–G) Primary mouse LMVECs (A, B, D, E, G) or MFLM-91U cells (C and F) were exposed to hyperoxia for 24 hours, followed by normoxia for 24 hours (refers to O2). (A) EdU incorporation was measured by flow cytometry, and a percentage of EdU+ cells was calculated. n = 8 in air and n = 7 in hyperoxia. (B) EdU incorporation was measured by flow cytometry after incubation with 2-DG (3 and 6 mM, 12 hours) during air recovery phase. n = 7 per group. (C) [3-13C]lactate was measured by the NMR when cells were incubated with [1,2-13C]glucose (20 mM, 24 hours) along with 6-AN (50 μM, 12 hours) or DHEA (50 μM, 12 hours) during air recovery phase. n = 6 in air and O2/veh groups; n = 5 in 6-AN and DHEA treatment groups. (D) Glycolytic rate assay was performed after incubation with 6-AN (50 μM), DHEA (50 μM), or 3-PO (10 μM) for 12 hours during air recovery phase. n = 32 in air and O2/veh groups; n = 8 in 6-AN, DHEA and 3-PO treatment groups. (E) EdU incorporation was measured by flow cytometry after incubation with 6-AN (25–100 μM), DHEA (50 and100 μM), and 3-PO (5 and10 μM) for 12 hours during air recovery phase. n = 7 in per group. (F) EdU was measured by flow cytometry in scramble and pgd siRNA–transfected cells. n = 5 in per group. (G) [13C]-labeled deoxynucleotides were measured by mass spectrometry when cells were incubated with 20 mM [U-13C]glucose for 24 hours during air recovery phase. n = 5 per group. *P < 0.05, **P < 0.01, ***P < 0.001 versus air (A–E), scramble siRNA/air (F), or air/veh (G); †P<0.05, ††P < 0.01, †††P < 0.001 versus hyperoxia/vehicle (B–E, and G) or scramble siRNA/hyperoxia (F) using 1-tailed t test (A) or ANOVA followed by Tukey-Kramer test (B–G).