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BackgroundThe "developmental origins of adult disease" hypothesis was originally derived from evidence linking low birth weight to cardiovascular diseases including stroke. Subsequently, it has been expanded to include developmental exposures to environmental contaminants as risk factors for adult onset disease.ObjectiveOur goal in this study was to test the hypothesis that developmental exposure to poly-chlorinated biphenyls (PCBs) alters stroke outcome in adults.MethodsWe exposed rats to the PCB mixture Aroclor 1254 (A1254) at 0.1 or 1 mg/kg/day in the maternal diet throughout gestation and lactation. Focal cerebral ischemia was induced at 6-8 weeks of age via middle cerebral artery occlusion, and infarct size was measured in the cerebral cortex and striatum at 22 hr of reperfusion. PCB congeners were quantified in brain tissue by gas chromatography with microelectron capture detection, and cortical and striatal expression of Bcl2 and Cyp2C11 were quantified by quantitative reverse transcriptase-polymerase chain reaction.ResultsDevelopmental exposure to A1254 significantly decreased striatal infarct in females and males at 0.1 and 1 mg/kg/day, respectively. Predominantly ortho-substituted PCB congeners were detected above background levels in brains of adult females and males exposed to A1254 at 1 but not 0.1 mg/kg/day. Effects of developmental A1254 exposure on Bcl2 and Cyp2C11 expression did not correlate with effects on infarct volume.ConclusionOur data provide proof of principle that developmental exposures to environmental contaminants influence the response of the adult brain to ischemic injury and thus represent potentially important determinants of stroke susceptibility.

BackgroundThe "developmental origins of adult disease" hypothesis was originally derived from evidence linking low birth weight to cardiovascular diseases including stroke. Subsequently, it has been expanded to include developmental exposures to environmental contaminants as risk factors for adult onset disease.ObjectiveOur goal in this study was to test the hypothesis that developmental exposure to poly-chlorinated biphenyls (PCBs) alters stroke outcome in adults.MethodsWe exposed rats to the PCB mixture Aroclor 1254 (A1254) at 0.1 or 1 mg/kg/day in the maternal diet throughout gestation and lactation. Focal cerebral ischemia was induced at 6-8 weeks of age via middle cerebral artery occlusion, and infarct size was measured in the cerebral cortex and striatum at 22 hr of reperfusion. PCB congeners were quantified in brain tissue by gas chromatography with microelectron capture detection, and cortical and striatal expression of Bcl2 and Cyp2C11 were quantified by quantitative reverse transcriptase-polymerase chain reaction.ResultsDevelopmental exposure to A1254 significantly decreased striatal infarct in females and males at 0.1 and 1 mg/kg/day, respectively. Predominantly ortho-substituted PCB congeners were detected above background levels in brains of adult females and males exposed to A1254 at 1 but not 0.1 mg/kg/day. Effects of developmental A1254 exposure on Bcl2 and Cyp2C11 expression did not correlate with effects on infarct volume.ConclusionOur data provide proof of principle that developmental exposures to environmental contaminants influence the response of the adult brain to ischemic injury and thus represent potentially important determinants of stroke susceptibility.

Aldolase C is regarded as the brain-specific form of fructose-1,6- bisphosphate aldolase whereas aldolase A is regarded as muscle-specific. In situ hybridization of mouse central nervous system using isozyme-specific probes revealed that aldolase A and C are expressed in complementary cell types. With the exception of cerebellar Purkinje cells, aldolase A mRNA is found in neurons; aldolase C message is detected in astrocytes, some cells of the pia mater, and Purkinje cells. We isolated aldolase C genomic clones that span the entire protein coding region from 1.5 kb 5' to the transcription start site to 0.5 kb 3' to the end of the last exon. The bacterial gene, lacZ, was inserted in two different locations and the constructs tested in transgenic mice. When the protein coding sequences were replaced with lacZ, three of five transgenic lines expressed β-galactosidase only in cells of the pia mater; one line also expressed in astrocyte-like cells. When lacZ was inserted into the final exon (and all structural gene sequences were retained) transgene expression was observed in astrocytes in all regions of the central nervous system as well as in pial cells. Thus, with the exception of Purkinje cell expression, the behavior of the full-length transgene mimics the endogenous aldolase C gene. The results with the shorter transgene suggest that additional enhancer elements exist within the intragenic sequences. The absence of Purkinje cell staining suggests that the cis elements required for this expression must be located outside of the sequences used in this study.

The sagittal organization of the mammalian cerebellum can be observed at the anatomical, physiological and biochemical level. Previous screening of monoclonal antibodies produced in our laboratory has identified two intracellular antigens, zebrin I and II, that occur exclusively in adult cerebellar Purkinje cells. As their name suggests, the zebrin antibody staining of the Purkinje cell population is not uniform. Rather, zebrin-positive Purkinje cells are organized in stripes or bands that run from anterior to posterior across most of the cerebellum; interposed between the zebrin-positive cells are bands of Purkinje cells that are zebrin-negative. Comparison of the position of the antigenic bands with the anatomy of afferent projections suggests that the bands are congruent with the basic developmental and functional 'compartments' of the cerebellum. We report the isolation of cDNA clones of the 36 x 10 3 M(r) antigen, zebrin II, by screening of a mouse cerebellum cDNA expression library. Sequence analysis reveals a 98% identity between our clone and the glycolytic isozyme, aldolase C. In order to more rigorously demonstrate the identity of the two proteins, we stained adult cerebellum with an independent monoclonal antibody raised against aldolase C. Anti-aldolase staining occurs in a previously unreported pattern of sagittal bands of Purkinje cells; the pattern is identical to that revealed by the zebrin II monoclonal. Further, in situ hybridization of antisense aldolase C riboprobe shows that the accumulation of zebrin II/aldolase C mRNA corresponds to the pattern of the zebrin antigen in Purkinje cells. Zebrin II/aldolase C gene expression is thus regulated at the level of transcription (or mRNA stability). In light of previous work that has demonstrated the cell autonomous and developmentally regimented expression of zebrin II, further studies of the regulation of this gene may lead to insights about the determination of cerebellar compartmentation.

The sagittal organization of the mammalian cerebellum can be observed at the anatomical, physiological and biochemical level. Previous screening of monoclonal antibodies produced in our laboratory has identified two intracellular antigens, zebrin I and II, that occur exclusively in adult cerebellar Purkinje cells. As their name suggests, the zebrin antibody staining of the Purkinje cell population is not uniform. Rather, zebrin-positive Purkinje cells are organized in stripes or bands that run from anterior to posterior across most of the cerebellum; interposed between the zebrin-positive cells are bands of Purkinje cells that are zebrin-negative. Comparison of the position of the antigenic bands with the anatomy of afferent projections suggests that the bands are congruent with the basic developmental and functional 'compartments' of the cerebellum. We report the isolation of cDNA clones of the 36 x 10 3 M(r) antigen, zebrin II, by screening of a mouse cerebellum cDNA expression library. Sequence analysis reveals a 98% identity between our clone and the glycolytic isozyme, aldolase C. In order to more rigorously demonstrate the identity of the two proteins, we stained adult cerebellum with an independent monoclonal antibody raised against aldolase C. Anti-aldolase staining occurs in a previously unreported pattern of sagittal bands of Purkinje cells; the pattern is identical to that revealed by the zebrin II monoclonal. Further, in situ hybridization of antisense aldolase C riboprobe shows that the accumulation of zebrin II/aldolase C mRNA corresponds to the pattern of the zebrin antigen in Purkinje cells. Zebrin II/aldolase C gene expression is thus regulated at the level of transcription (or mRNA stability). In light of previous work that has demonstrated the cell autonomous and developmentally regimented expression of zebrin II, further studies of the regulation of this gene may lead to insights about the determination of cerebellar compartmentation.

The sagittal organization of the mammalian cerebellum can be observed at the anatomical, physiological and biochemical level. Previous screening of monoclonal antibodies produced in our laboratory has identified two intracellular antigens, zebrin I and II, that occur exclusively in adult cerebellar Purkinje cells. As their name suggests, the zebrin antibody staining of the Purkinje cell population is not uniform. Rather, zebrin-positive Purkinje cells are organized in stripes or bands that run from anterior to posterior across most of the cerebellum; interposed between the zebrin-positive cells are bands of Purkinje cells that are zebrin-negative. Comparison of the position of the antigenic bands with the anatomy of afferent projections suggests that the bands are congruent with the basic developmental and functional 'compartments' of the cerebellum. We report the isolation of cDNA clones of the 36 x 10 3 M(r) antigen, zebrin II, by screening of a mouse cerebellum cDNA expression library. Sequence analysis reveals a 98% identity between our clone and the glycolytic isozyme, aldolase C. In order to more rigorously demonstrate the identity of the two proteins, we stained adult cerebellum with an independent monoclonal antibody raised against aldolase C. Anti-aldolase staining occurs in a previously unreported pattern of sagittal bands of Purkinje cells; the pattern is identical to that revealed by the zebrin II monoclonal. Further, in situ hybridization of antisense aldolase C riboprobe shows that the accumulation of zebrin II/aldolase C mRNA corresponds to the pattern of the zebrin antigen in Purkinje cells. Zebrin II/aldolase C gene expression is thus regulated at the level of transcription (or mRNA stability). In light of previous work that has demonstrated the cell autonomous and developmentally regimented expression of zebrin II, further studies of the regulation of this gene may lead to insights about the determination of cerebellar compartmentation.