The Role of Endoplasmic Reticulum in the Differential Endurance against Redox Stress in Cortical and Spinal Astrocytes from the Newborn SOD1G93A Mouse Model of Amyotrophic Lateral Sclerosis

Abstract

Recent studies reported that the uptake of [18F]-fluorodeoxyglucose (FDG) is increased in the spinal cord (SC) and decreased in the motor cortex (MC) of patients with ALS, suggesting that the disease might differently affect the two nervous districts with different time sequence or with different mechanisms. Here we show that MC and SC astrocytes harvested from newborn B6SJL-Tg (SOD1G93A) 1Gur mice could play different roles in the pathogenesis of the disease. Spectrophotometric and cytofluorimetric analyses showed an increase in redox stress, a decrease in antioxidant capacity and a relative mitochondria respiratory uncoupling in MC SOD1G93A astrocytes. By contrast, SC mutated cells showed a higher endurance against oxidative damage, through the increase in antioxidant defense, and a preserved respiratory function. FDG uptake reproduced the metabolic response observed in ALS patients: SOD1G93A mutation caused a selective enhancement in tracer retention only in mutated SC astrocytes, matching the activity of the reticular pentose phosphate pathway and, thus, of hexose-6P dehydrogenase. Finally, both MC and SC mutated astrocytes were characterized by an impressive ultrastructural enlargement of the endoplasmic reticulum (ER) and impairment in ER–mitochondria networking, more evident in mutated MC than in SC cells. Thus, SOD1G93A mutation differently impaired MC and SC astrocyte biology in a very early stage of life.

Micro-RNAs Shuttled by Extracellular Vesicles Secreted from Mesenchymal Stem Cells Dampen Astrocyte Pathological Activation and Support Neuroprotection in In-Vitro Models of ALS

“…Spinal cord astrocyte primary cell cultures were prepared from late symptomatic (120-day-old) adult SOD1 G93A and age-matched WT mice as previously described [ 53 , 54 ]. In detail, late symptomatic (120-day-old) SOD1 G93A mice and age-matched WT mice were euthanized by cervical dislocation by well-trained personnel and spinal cords were rapidly removed.…”

“…After 7DIV, adherent astrocytes were detached by Trypsin-EDTA 1× (Euroclone, S.p.A, Milan, Italy, Cat# ECB3052B) and re-plated on pre-coated 35 mm Petri dishes to obtain the homogeneous confluence at the optimal density of 10 5 cells. The purity of spinal cord adult astrocyte cell cultures was checked with flow cytometry and immunofluorescence as previously described [ 54 ]. For immunofluorescence (IF) analyses, astrocytes were also re-plated on pre-coated glass coverslips placed at the bottom of 24-multiwell plates, at a density of 3 × 10 4 cells per well.…”

Astrocytes in Neurodegeneration: Inspiration From Genetics

“…Animal models for studying astrocytes with SOD1 mutation investigated astrocytes changes at different stages. In the early and prodromal stages of ALS, astrocytes in the motor cortex and spinal cord of SOD1 G93A mice demonstrated different vulnerability to oxidative stress as astrocytes in the motor cortex of the SOD1 G93A mouse model had increased the oxidative stress, decreased the antioxidant capacity, and a relative mitochondria respiratory uncoupling, whereas the astrocytes in the spinal cord showed a higher endurance against oxidative damage through an increased antioxidant defense and a preserved mitochondrial respiratory function (Marini et al, 2021). The different responses of astrocytes from the motor cortex and spinal cords to oxidative stress indicate selective damage in ALS progression.…”

“…Despite the fact that astrocytes in the motor cortex and spinal cord had different endurance in the early stage of the disease, widespread and excessive oxidative stress in astrocytes was activated in the late stage of the SOD1 G93A mouse model (López-Blanch et al, 2021). In the SOD1 G93A mouse models, astrocytes from both the motor cortex and the spinal cords were characterized by ERmitochondrial impairments, which were more pronounced in the mutated motor cortex than in the spinal cord cells (Marini et al, 2021). NF-κB increased in the symptomatic stage as well (Gomes et al, 2019), and astrocyte NF-κB-dependent activation accelerated the disease progression (Ouali Alami et al, 2018).…”

Opportunistic skeletal muscle metrics as prognostic tools in metastatic castration-resistant prostate cancer patients candidates to receive Radium-223

“…On the one side, the inflamed SM might be FDG-avid due to the high content in inflammatory infiltrates. Alternatively, given the oxidative environment promoted by SM inflammation [ 56 ], the increased FDG uptake may at least partially reflect the activation of NADPH generation by a pentose phosphate pathway selectively located within the endoplasmic reticulum, as previously documented in cancer cells [ 57 , 58 ], neurons [ 59 ], astrocytes [ 60 ], cardiomyocytes [ 61 ], and, more importantly, in the SM [ 62 , 63 ].…”