CNTF enhances aerobic glycolysis and anabolic activities in degenerating retinas

Abstract

ABSTRACTCiliary neurotrophic factor (CNTF) has potent neuroprotective activity in retinal degeneration animal models, yet the cellular mechanisms underlying its broad neuronal survival effects remain unclear. Here, we investigated the impact of CNTF on retinal metabolism in a mouse model of human retinitis pigmentosa. CNTF treatment resulted in improved mitochondrial morphology in mutant rod photoreceptors, but also led to reduced oxygen consumption and suppression of respiratory chain complex activities. Metabolomics analyses detected significantly higher levels of ATP and the energy currency phospho-creatine post CNTF exposure. In addition, CNTF-treated retinas contained elevated glycolytic metabolites and showed increased expression of genes and active enzymes of the glycolytic pathway. Metabolomics analyses also revealed increased TCA cycle products, lipid biosynthetic pathway intermediates, nucleotides, and amino acids, indicating an overall CNTF-dependent augmentation of anabolic activities. Moreover, CNTF treatment restored the key antioxidant glutathione to the wild type level in the degenerating retina. Taken together, these results demonstrate that CNTF profoundly impacts the metabolic status of degenerating retinas by promoting aerobics glycolysis and anabolism, enhancing energy supply, and restoring redox homeostasis. Our study thus reveals important cellular mechanisms underlying CNTF-mediated neuroprotection and provides novel insight for the on-going CNTF clinical trials treating blinding diseases.