👤 Christian S Carl

Retinal neurodegenerative diseases such as Age-related Macular Degeneration (AMD) and Retinitis Pigmentosa cause irreversible vision loss due to the limited regenerative capacity of the mammalian retina. Cerium oxide nanoparticles (nanoceria) are emerging therapeutics against oxidative stress and inflammation, major drivers of photoreceptor degeneration, and have demonstrated morphological and functional neuroprotection in preclinical models. However, the genome-wide transcriptional mechanisms underlying these effects remain incompletely characterized. We performed retinal transcriptomic analysis in a rat AMD model induced by intense light and treated intravitreally with nanoceria. Six groups were analyzed: control, light damage, vehicle, nanoceria, vehicle + light damage, and nanoceria + light damage. Light damage activated inflammatory and apoptotic programs, with upregulation of cytokines (Tnf, Il6, Il1b, Ccl2) and downregulation of photoreceptor genes (Rho, Pde6a/b, Gnat1). Nanoceria treatment counteracted these effects, suppressing pro-inflammatory mediators, restoring antioxidative genes (Nfe2l2, Gclc, Sod2), and enhancing neuroprotective factors (Bdnf, Cntf, Ngf). Pathway analyses revealed inhibition of TNF/NF-κB/IL-17 signaling and activation of PI3K-Akt, JAK-STAT, and neurotrophin pathways. Unexpectedly, nanoceria also modulated amino acid and insulin metabolism (Ass1, Cps1, Insr, Irs1, Slc2a4) and reactivated transcription factors (Ascl1, Sox2, Notch1) typically silent in adult retina. Our findings highlight nanoceria as a multifunctional therapeutic that mitigates retinal degeneration by coordinating oxidative, inflammatory, and regenerative responses. Together with prior morphological and functional validations, these results support the translational potential of nanoceria for treating retinal neurodegenerative diseases. Show less

Low-carbohydrate, high-fat diets under eucaloric conditions are associated with several health-beneficial metabolic effects in humans, particularly in the liver. We recently observed that apolipoprotein A-IV (apoA-IV), a highly abundant apolipoprotein, was among the most upregulated proteins in circulation after six weeks of consuming a high-fat diet in humans. However, the impact of dietary changes in regulating apoA-IV, and the potential effects of apoA-IV on regulation of glucose- and lipid metabolism remain to be fully established. We investigated the regulation of circulating fasting concentrations of apoA-IV in humans in response to diets enriched in either fat or carbohydrates. Moreover, to study the whole-body and tissue-specific glucose and lipid metabolic effects of apoA-IV, we administrered apoA-IV recombinant protein to mice and isolated pancreatic islets. We demonstrate that in healthy human individuals high-fat intake increased fasting plasma apoA-IV concentrations by up to 54%, while high-carbohydrate intake suppressed plasma apoA-IV concentrations. In mice, administration of apoA-IV acutely lowered blood glucose levels both in lean and obese mice. Interestingly, this was related to a dual mechanism, involving both inhibition of hepatic glucose production and increased glucose uptake into white and brown adipose tissues. In addition to an effect on hepatic glucose production, the apoA-IV-induced liver proteome revealed increased capacity for lipoprotein clearance. The effects of apoA-IV in the liver and adipose tissues were concomitant with increased whole-body fatty acid oxidation. Upon glucose stimulation, an improvement in glucose tolerance by apoA-IV administration was related to potentiation of glucose-induced insulin secretion, while apoA-IV inhibited glucagon secretion ex vivo in islets. We find that apoA-IV is potently increased by intake of fat in humans, and that several beneficial metabolic effects, previously associated with high fat intake in humans, are mimicked by administration of apoA-IV protein to mice. Show less

Nodal activity in the left lateral plate mesoderm (LPM) is required to activate left-sided Nodal signaling in the epithalamic region of the zebrafish forebrain. Epithalamic Nodal signaling subsequently determines the laterality of neuroanatomical asymmetries. We show that overactivation of Wnt/Axin1/beta-catenin signaling during late gastrulation leads to bilateral epithalamic expression of Nodal pathway genes independently of LPM Nodal signaling. This is consistent with a model whereby epithalamic Nodal signaling is normally bilaterally repressed, with Nodal signaling from the LPM unilaterally alleviating repression. We suggest that Wnt signaling regulates the establishment of the bilateral repression. We identify a second role for the Wnt pathway in the left/right regulation of LPM Nodal pathway gene expression, and finally, we show that at later stages Axin1 is required for the elaboration of concordant neuroanatomical asymmetries. Show less