Apoptotic bodies in cultures under both protocols, as compared to control (data not shown). Immunofluorescence staining for cleaved caspase-3 revealed no difference in theBiochemical Parameters in Culture Media after Peptide M exposure to GA and 3-OHGAGlucose and Lactate. As compared to controls, GA and 3OHGA exposure caused a significant decrease in the glucose levels under protocol B (DIV 14), while the glucose levels of immature cultures (protocol A, DIV 8) were not significantly changed (Figure 5A). In parallel, a significant increase in lactate levels wasBrain Cell Damage in Glutaric Aciduria Type IFigure 3. Effects of GA and 3-OHGA on astrocytes. (Left panel) Immunohistochemical staining for glial fibrillary acidic protein (GFAP) on cryosections of cultures derived from protocol A (DIV 8) and protocol B (DIV 14). Swollen proximal fibers are indicated by black arrows. Scale bar: 100 mm. (Right panel) Representative western blots with data quantification of whole-cell lysates for GFAP for protocol A (DIV 8, above) and protocol B (DIV 14, below). Actin was used as a loading control. The quantifications of GFAP levels are expressed as percentage of respective controls. The values represent the mean 6 SD from 3 replicates taken from 2 independent experiments. doi:10.1371/journal.pone.0053735.Benzocaine gnumber of positively stained cells (e.g. apoptotic) in cultures exposed to GA and 3-OHGA in both 26001275 treatment protocols as compared to control (Figure 6A, left panel). Accordingly, no significant changes were observed on activated caspase-3 level assessed by western blotting under both metabolites treatment at DIV 14. In protocol A, a tendency of activated caspase-3 to decrease in GA- and 3-OHGA-exposed aggregates was observed, however, the changes were not significant (Figure 6A, right panel). Interestingly, TUNEL labeling (green staining) showed an important signal increase for cultures treated with 3-OHGA on DIV 8, which only partially co-localized (yellow staining) with cleaved caspase-3-labeled apoptotic cells (red signal) (Figure 6B). This suggests an induction of non-apoptotic cell death in developing brain cells under 3-OHGA exposure. TUNEL signal in 3-OHGA exposed cultures was homogenously distributed over the entire aggregate, suggesting that 3-OHGA diffused well from the medium into the whole aggregate (Figure 6B, 106magnifications).DiscussionWe used 3D organotypic brain cell cultures in aggregates to explore, in vitro, the effects of the two main metabolites (GA and 3OHGA) accumulated in body fluids of subjects affected by GA-I. Our in vitro model is particularly suitable for studying neurotoxicity because the aggregates contain all types of brain cells with their spontaneous connections between each other. In addition, this model reproduces early phases of brain development and has proven to be optimal to study differential effects of metabolic derangements (such as hyperammonemia) in developing brain compared to adult brain tissue [14,15,16,18]. This is particularly important when studying a disorder in which the most dramatic brain damage occurs in early childhood. In our study, we could confirm that both GA and 3-OHGA were deleterious for brain cells during development, but 3-OHGA turned out to be the most toxic metabolite. The most striking effect of 3-OHGA on the aggregates was massive tissue destruction with wide areas of cell death, which was evident on DIV 14 (Figures 2 and 3). In both developmental stages (DIV 8 and 14) astrocytes appear.Apoptotic bodies in cultures under both protocols, as compared to control (data not shown). Immunofluorescence staining for cleaved caspase-3 revealed no difference in theBiochemical Parameters in Culture Media after Exposure to GA and 3-OHGAGlucose and Lactate. As compared to controls, GA and 3OHGA exposure caused a significant decrease in the glucose levels under protocol B (DIV 14), while the glucose levels of immature cultures (protocol A, DIV 8) were not significantly changed (Figure 5A). In parallel, a significant increase in lactate levels wasBrain Cell Damage in Glutaric Aciduria Type IFigure 3. Effects of GA and 3-OHGA on astrocytes. (Left panel) Immunohistochemical staining for glial fibrillary acidic protein (GFAP) on cryosections of cultures derived from protocol A (DIV 8) and protocol B (DIV 14). Swollen proximal fibers are indicated by black arrows. Scale bar: 100 mm. (Right panel) Representative western blots with data quantification of whole-cell lysates for GFAP for protocol A (DIV 8, above) and protocol B (DIV 14, below). Actin was used as a loading control. The quantifications of GFAP levels are expressed as percentage of respective controls. The values represent the mean 6 SD from 3 replicates taken from 2 independent experiments. doi:10.1371/journal.pone.0053735.gnumber of positively stained cells (e.g. apoptotic) in cultures exposed to GA and 3-OHGA in both 26001275 treatment protocols as compared to control (Figure 6A, left panel). Accordingly, no significant changes were observed on activated caspase-3 level assessed by western blotting under both metabolites treatment at DIV 14. In protocol A, a tendency of activated caspase-3 to decrease in GA- and 3-OHGA-exposed aggregates was observed, however, the changes were not significant (Figure 6A, right panel). Interestingly, TUNEL labeling (green staining) showed an important signal increase for cultures treated with 3-OHGA on DIV 8, which only partially co-localized (yellow staining) with cleaved caspase-3-labeled apoptotic cells (red signal) (Figure 6B). This suggests an induction of non-apoptotic cell death in developing brain cells under 3-OHGA exposure. TUNEL signal in 3-OHGA exposed cultures was homogenously distributed over the entire aggregate, suggesting that 3-OHGA diffused well from the medium into the whole aggregate (Figure 6B, 106magnifications).DiscussionWe used 3D organotypic brain cell cultures in aggregates to explore, in vitro, the effects of the two main metabolites (GA and 3OHGA) accumulated in body fluids of subjects affected by GA-I. Our in vitro model is particularly suitable for studying neurotoxicity because the aggregates contain all types of brain cells with their spontaneous connections between each other. In addition, this model reproduces early phases of brain development and has proven to be optimal to study differential effects of metabolic derangements (such as hyperammonemia) in developing brain compared to adult brain tissue [14,15,16,18]. This is particularly important when studying a disorder in which the most dramatic brain damage occurs in early childhood. In our study, we could confirm that both GA and 3-OHGA were deleterious for brain cells during development, but 3-OHGA turned out to be the most toxic metabolite. The most striking effect of 3-OHGA on the aggregates was massive tissue destruction with wide areas of cell death, which was evident on DIV 14 (Figures 2 and 3). In both developmental stages (DIV 8 and 14) astrocytes appear.

Apoptotic bodies in cultures under both protocols, as compared to control

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