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Friday, May 8, 2009
Northwest Hall (Chicago Hilton)
11:00 AM
Background: Altered brain development during embryogenesis and early postnatal life has been hypothesized responsible for abnormal behaviors in autism. A specific genetic background that alters vulnerability to some environmental insults has been suggested in the etiology of autism; however, the specific pathomechanisms have not been identified. Recently, we showed that sera from children with autism alter maturation of human neuronal progenitor cells (hNPCs) in culture. Results suggest that regulatory factors present in sera from people with autism affect pre-programmed neurogenesis. This cell culture model of neurogenesis in autism seems to be suitable to study the effect of factors from external environment, e.g., oxidative stress that is putative risk factor in autism.
Objectives: To evaluate the susceptibility of hNPCs to oxidative stress during different stages of neuronal differentiation in an “autistic environment”, i.e., stimulated with sera from children with autism. Methods: Neurospheres of hNPCs were exposed to a mild oxidative stress--non-cytotoxic concentrations of ferrous ions--applied at the beginning and during differentiation induced by sera from children with autism and controls at different ages. Apoptosis was evaluated based on morphology of cellular nuclei, DNA fragmentation and Bcl2 expression. Proliferation of hNPCs was tested using incorporation of bromodeoxyuridine during a 2 h pulse. Neuronal development was estimated by expression of specific markers by immunocytochemistry and Western blotting.
Results: Treatment with a 200μM solution of ferrous ions did not increase the mortality of hNPCs, apoptosis and formation of carbonyls—a marker of oxidative protein damage. Proliferation of cells was affected by the treatments, as was examined in a three-way ANOVA in which autistic status, age and schedule of the exposure to ferrous ions were entered as factors. The overall ANOVA was significant (F(15 df)=23.6, p < .001). Age of serum donors was marginally significant (F(1 df) = 4.01, p = .047), and stage of cell differentiation during treatment was highly significant (F(3 df) = 103.5, p < .001). The degree of proliferation was affected by autistic status to a different degree among the experimental groups (F(3 df) = 8.31, p < .001). Post-hoc comparisons showed significant differences between the cultures in which ferrous ions were or were not added during differentiation of neuronal progenitor cells (p < .001). Pairwise ANOVAs revealed that the effect differed between the autistic and control groups. The treatments did not influence expression of neuronal markers during 48 hours of culture.
Conclusions: (1) Factors present in sera of autistic children altered the sensitivity of differentiating hNPCs to a mild oxidative stress. Results suggest that oxidative stress may affect renewal and development of NPCs in autism. (2) hNPCs exposed to factors present in autistic sera may be a useful model to study the pathomechanisms of environmental risk factor that affect neurogenesis and brain plasticity leading to altered behavior in autism.
Objectives: To evaluate the susceptibility of hNPCs to oxidative stress during different stages of neuronal differentiation in an “autistic environment”, i.e., stimulated with sera from children with autism. Methods: Neurospheres of hNPCs were exposed to a mild oxidative stress--non-cytotoxic concentrations of ferrous ions--applied at the beginning and during differentiation induced by sera from children with autism and controls at different ages. Apoptosis was evaluated based on morphology of cellular nuclei, DNA fragmentation and Bcl2 expression. Proliferation of hNPCs was tested using incorporation of bromodeoxyuridine during a 2 h pulse. Neuronal development was estimated by expression of specific markers by immunocytochemistry and Western blotting.
Results: Treatment with a 200μM solution of ferrous ions did not increase the mortality of hNPCs, apoptosis and formation of carbonyls—a marker of oxidative protein damage. Proliferation of cells was affected by the treatments, as was examined in a three-way ANOVA in which autistic status, age and schedule of the exposure to ferrous ions were entered as factors. The overall ANOVA was significant (F(15 df)=23.6, p < .001). Age of serum donors was marginally significant (F(1 df) = 4.01, p = .047), and stage of cell differentiation during treatment was highly significant (F(3 df) = 103.5, p < .001). The degree of proliferation was affected by autistic status to a different degree among the experimental groups (F(3 df) = 8.31, p < .001). Post-hoc comparisons showed significant differences between the cultures in which ferrous ions were or were not added during differentiation of neuronal progenitor cells (p < .001). Pairwise ANOVAs revealed that the effect differed between the autistic and control groups. The treatments did not influence expression of neuronal markers during 48 hours of culture.
Conclusions: (1) Factors present in sera of autistic children altered the sensitivity of differentiating hNPCs to a mild oxidative stress. Results suggest that oxidative stress may affect renewal and development of NPCs in autism. (2) hNPCs exposed to factors present in autistic sera may be a useful model to study the pathomechanisms of environmental risk factor that affect neurogenesis and brain plasticity leading to altered behavior in autism.