Abstract
Purpose :
We have investigated systemic biochemical changes that impact angiogenesis in OIR. We compared the transcriptome of the liver and retina between the BALBc/ByJ (OIR-resistant) and C57BL/6J (OIR-susceptible) mouse strains in phase 1 of OIR on P12. We also performed the plasma proteomics and ELSIA to examine secretome at systems levels. Multi-omics data was used to correlate hepatic gene expression with the OIR defects and proteins in the plasma to find biochemical pathways that induce the secretion of biochemicals into the plasma, positively or negatively affecting retinal angiogenesis in phase 1 of OIR.
Methods :
All the in vivo experiments were performed per IUCAC-approved protocol, using the OIR mouse model. Mice were sacrificed on postnatal day 12 (P12). RNA sequencing was performed by Nonogene Inc. Plasma proteomics were performed with the help of SOMAscan and ELISA kits.
Results :
RNA seq data indicated that the BALBc/ByJ (OIR-resistant) and C57BL/6J (OIR-susceptible) differ in the expression of anabolic and catabolic genes. The expression of polyamine enzymes (Arg2 and Samdc, p-value <0.01), serine transport (Snat1, p-value <0.0001) and utilization enzyme (Shmt2, p-value <0.001) were higher in the BALBc/ByJ in comparison to C57BL/6J mouse strain, in hyperoxia. Previously we demonstrated that hyperoxia induces glutamine-fueled anaplerosis. Our data indicates that the BALBc/ByJ relies on medium-chain fatty acid (Acadm, p-value 0.01; Ech1, p-value 0.05; Acaa2, p-value <0.05) for its anaplerosis, which prevents faulty upregulation of glutamine based anaplerosis. These changes negatively correlated with Pparα in the retina but positively correlated with hepatic Fgf21. We found strong correlations between the Ffg21 in the liver and FGF21 in the plasma (r=0.99). We also looked at the transcription factors known to induce Fgf21 in the liver and found that Pparα (r=0.99) and Crebh (r=0.88) showed positive correlations. Plasma adiponectin and FGF21 proteins showed a negative correlation (r=-0.78), and adiponectin levels also showed no correlation with protection seen in BALBc/ByJ.
Conclusions :
FGF21 is produced by the liver in P12 old mice and positively correlates with protection against OIR. A negative correlation between FGF21 and Adiponectin demonstrates that the protection in BALBc/ByJ is independent of Adiponectin. Hepatic Pparα and Crebh regulate systemic FGF21 levels, implying their role in FGF21 induction in the liver.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.