Publicação
Primary Cilia and the Thioredoxin 1/Thioredoxin Reductase 1 System in the Cellular Response to Hyperglycemia
| Resumo: | Diabetes Mellitus is a global health challenge where chronic hyperglycemia leads to Diabetic Retinopathy (DR), a primary cause of vision loss and preventable blindness. The retina is particularly susceptible to glucose toxicity due to its high metabolic demand and insulin-independent glucose uptake, which directly exposes retinal cells to reactive oxygen species (ROS). While the Retinal Pigment Epithelium (RPE) is vital for maintaining retinal homeostasis, its neuroprotective capacity is severely impaired under these pathological conditions. This study aimed to characterize the thioredoxin system (Trx-1/TrxR-1) response to hyperglycemia (25 mM D-glucose) in hTERT RPE-1 cells, with a specific focus on the mediatory role of the primary cilium (PC). By employing an optimized protocol to mimic the pathophysiological conditions of DR, alongside fluorescence microscopy and Western blot analysis, we demonstrated that both the levels and subcellular localization of Trx-1 remained unchanged. These findings suggest that, under these experimental conditions, the induction of oxidative stress is likely moderate. A key finding of this work was the observation of a functional uncoupling between Trx-1 and TrxR-1, where the PC selectively modulated TrxR-1 dynamics without affecting Trx-1. Enzymatic assays revealed a paradox: Trx-1 activity remained stable while TrxR-1 activity decreased in ciliated cells, likely due to compensatory mechanisms such as the glutathione system. Overall, together with our previous observations, these findings support the concept that the PC functions as a metabolic signaling hub, communicating cellular metabolic status to the genomic integrity machinery and potentially regulating γH2AX foci through Trx-1/TrxR-1–mediated control of ATM (ataxia telangiectasia mutated) phosphorylation. |
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| Autores principais: | Faria,Rodrigo dos Santos Baltazar |
| Assunto: | Hyperglycemia Primary Cilia Thioredoxin 1 Thioredoxin reductase 1 RPE cells |
| Ano: | 2026 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso embargado |
| Instituição associada: | Universidade de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório da Universidade de Lisboa |
| Resumo: | Diabetes Mellitus is a global health challenge where chronic hyperglycemia leads to Diabetic Retinopathy (DR), a primary cause of vision loss and preventable blindness. The retina is particularly susceptible to glucose toxicity due to its high metabolic demand and insulin-independent glucose uptake, which directly exposes retinal cells to reactive oxygen species (ROS). While the Retinal Pigment Epithelium (RPE) is vital for maintaining retinal homeostasis, its neuroprotective capacity is severely impaired under these pathological conditions. This study aimed to characterize the thioredoxin system (Trx-1/TrxR-1) response to hyperglycemia (25 mM D-glucose) in hTERT RPE-1 cells, with a specific focus on the mediatory role of the primary cilium (PC). By employing an optimized protocol to mimic the pathophysiological conditions of DR, alongside fluorescence microscopy and Western blot analysis, we demonstrated that both the levels and subcellular localization of Trx-1 remained unchanged. These findings suggest that, under these experimental conditions, the induction of oxidative stress is likely moderate. A key finding of this work was the observation of a functional uncoupling between Trx-1 and TrxR-1, where the PC selectively modulated TrxR-1 dynamics without affecting Trx-1. Enzymatic assays revealed a paradox: Trx-1 activity remained stable while TrxR-1 activity decreased in ciliated cells, likely due to compensatory mechanisms such as the glutathione system. Overall, together with our previous observations, these findings support the concept that the PC functions as a metabolic signaling hub, communicating cellular metabolic status to the genomic integrity machinery and potentially regulating γH2AX foci through Trx-1/TrxR-1–mediated control of ATM (ataxia telangiectasia mutated) phosphorylation. |
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