Gestational long-term hypoxia induces metabolomic reprogramming and phenotypic transformations in fetal sheep pulmonary arteries

Abstract

Gestational long-term hypoxia increases the risk of myriad diseases in infants including persistent pulmonary hypertension. Similar to humans, fetal lamb lung development is susceptible to long-term intrauterine hypoxia, with structural and functional changes associated with the development of pulmonary hypertension including pulmonary arterial medial wall thickening and dysregulation of arterial reactivity, which culminates in decreased right ventricular output. To further explore the mechanisms associated with hypoxia-induced aberrations in the fetal sheep lung, we examined the premise that metabolomic changes and functional phenotypic transformations occur due to intrauterine, long-term hypoxia. To address this, we performed electron microscopy, Western immunoblotting, calcium imaging, and metabolomic analyses on pulmonary arteries isolated from near-term fetal lambs that had been exposed to low- or high-altitude (3801 m) hypoxia for the latter 110+ days of gestation. Our results demonstrate that the sarcoplasmic reticulum was swollen with high luminal width and distances to the plasma membrane in the hypoxic group. Hypoxic animals presented with higher endoplasmic reticulum stress and suppressed calcium storage. Metabolically, hypoxia was associated with lower levels of multiple omega-3 polyunsaturated fatty acids and derived lipid mediators (e.g. eicosapentanoic acid, docosahexaenoic acid, alpha-linolenic acid, 5-hydroxyeicosapentaenoic acid (5-HEPE), 12-HEPE, 15-HEPE, prostaglandin E3, and 19(20)-epoxydocosapentaenoic acid), and higher levels of some omega-6 metabolites (p<0.02) including 15-Keto prostaglandin E2 and linoleoylglycerol. Collectively, the results reveal broad evidence for long-term hypoxia-induced metabolic reprogramming and phenotypic transformations in the pulmonary arteries of fetal sheep, conditions that likely contribute to the development of persistent pulmonary hypertension.

Long-Term Hypoxia Negatively Influences Ca2+ Signaling in Basilar Arterial Myocytes of Fetal and Adult Sheep

“…Depression in InsP 3 signaling may therefore also underlie the suppression in membrane depolarization induced Ca 2+ oscillations we report here. With regards to the current findings that LTH restricts cellular Ca 2+ responses, our previous data illustrate that the SER Ca 2+ stores of sheep pulmonary arteries are largely intact regardless of age or hypoxic stress ( Hadley et al, 2012 ), although there is significant SER stress as evidenced by structural changes in the SER of pulmonary arterial myocytes as well as increases in markers of SER stress ( Leslie et al, 2021 ). Such evidence suggests that the major aberrations in Ca 2+ responses are more likely due to dysregulation of pathways critical to regulating Ca 2+ signaling that may involve SER stress as opposed to fundamental disruption of the storage capabilities of the intracellular Ca 2+ stores.…”

“…Much like the impact on whole-cell Ca 2+ oscillations, this parallel effect of LTH on basilar and pulmonary arterial myocytes suggests there may be a common underlying mechanism whereby LTH suppresses depolarization induced activation of Ca 2+ sparks. Presumably, this would be due to a loss in communication between plasma membrane channels and ryanodine receptors on the SER, possibly involving SER stress such as we have shown in fetal pulmonary arterial myocytes ( Leslie et al, 2021 ). These losses in communication potentially include L-type Ca 2+ channels but may also involve disruption in T-type Ca 2+ channels or TRPV4, which are also important to Ca 2+ spark activation in vascular myocytes ( Earley et al, 2005 ; Harraz et al, 2014 , 2015 ).…”

Lipidomic analysis revealed n‐3 polyunsaturated fatty acids suppressed choroidal thinning and myopia progression in mice

“…N‐3 polyunsaturated fatty acids (PUFAs) have anti‐inflammatory and cardioprotective effects 19–24 and play an important role in the body as components of phospholipids that form the structures of cell membranes and provide energy for the body. PUFAs have wide‐ranging functions in cardiovascular, pulmonary, and immune systems 23–27 . Recently, n‐3 PUFAs have been reported to have various advantageous effects on eye disorders, 28–30 and investigation of their suppressive effect on myopia progression has attracted our attention.…”

“…[11][12][13] Crocetin exhibits multiple activities, such as antioxidation, anti-inflammatory, and anti-atherosclerosis effects. [14][15][16][17][18] N-3 polyunsaturated fatty acids (PUFAs) have anti-inflammatory and cardioprotective effects [19][20][21][22][23][24] and play an important role in the body as components of phospholipids that form the structures of cell membranes and provide energy for the body. PUFAs have wide-ranging functions in cardiovascular, pulmonary, and immune systems.…”

“…PUFAs have wide-ranging functions in cardiovascular, pulmonary, and immune systems. [23][24][25][26][27] Recently, n-3 PUFAs have been reported to have various advantageous effects on eye disorders, [28][29][30] and investigation of their suppressive effect on myopia progression has attracted our attention.…”