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O Heinonen

Publications and source records attributed to O Heinonen.

At least 19 recordsLinked to original sources
PubMed2001

Palmitoyl protein thioesterase (PPT) localizes into synaptosomes and synaptic vesicles in neurons: implications for infantile neuronal ceroid lipofuscinosis (INCL).

A deficiency of palmitoyl protein thioesterase (PPT) leads to the neurodegenerative disease infantile neuronal ceroid lipofuscinosis (INCL), which is characterized by an almost complete loss of cortical neurons. PPT expressed in COS-1 cells is recognized by the mannose-6-phosphate receptor (M6PR) and is routed to lysosome, but a substantial fraction of PPT is secreted. We have here determined the neuronal localization of PPT by confocal microscopy, cryoimmunoelectron microscopy and cell fractionation. In mouse primary neurons and brain tissue, PPT is localized in synaptosomes and synaptic vesicles but not in lysosomes. Furthermore, in polarized epithelial Caco-2 cells, PPT is localized exclusively to the basolateral site, in contrast to the classical lysosomal enzyme, aspartylglucosaminidase (AGA), which is localized in the apical site. The current data imply that PPT has a role outside the lysosomes in the brain and may be associated with synaptic functioning. This finding opens a new route to study the neuropathological events associated with INCL.

Animals↗
PubMed2000

CLN-1 and CLN-5, genes for infantile and variant late infantile neuronal ceroid lipofuscinoses, are expressed in the embryonic human brain.

Mutations in the CLN-1 and CLN-5 genes underlie the infantile, and Finnish variant of the late-infantile, neuronal ceroid lipofuscinoses, respectively. These disorders are characterized by a massive neuronal death early in childhood. We have studied mRNA and protein expression of CLN-1 and CLN-5 in embryonic human brains. The spatial and temporal distributions of CLN-1 and CLN-5 were similar in the embryonic human brain. Both genes are expressed at the beginning of cortical neurogenesis, and this expression increases as cortical development proceeds. In the developing cortical plate, expression is found in postmitotic migrating neuroblasts and neuroblasts that have completed migration. Expression was intense also in cells of the thalamus as well as in the future Purkinje cell layer of the cerebellum. These findings indicate that expression of CLN-1 and CLN-5 may be significant for development of a wide range of maturating neurons.

Brain↗
PubMed2000

Expression of palmitoyl protein thioesterase in neurons.

Infantile neuronal ceroid lipofuscinosis (INCL) is a severe neurodegenerative disorder in childhood that is caused by mutations in the gene encoding lysosomal palmitoyl protein thioesterase (PPT). INCL is characterized by massive and selective loss of cortical neurons. Here we have analyzed the intracellular processing and localization of adenovirus-mediated PPT in mouse primary neurons and NGF-induced PC-12 cells. The neuronal processing of PPT was found to be similar to that observed in peripheral cells, and a significant amount of the PPT enzyme was secreted in the primary neurons. Immunofluorescence analysis of the neuronal cells infected with wild-type PPT showed a granular staining pattern in the cell soma and neuronal shafts. Interestingly, PPT was also found in the synaptic ends of the neuronal cells and the staining pattern of the enzyme colocalized to a significant extent with the synaptic markers SV2 and synaptophysin. These in vitro data correspond with the distribution of endogeneous PPT in mouse brain and suggest that PPT may not solely be a lysosomal hydrolase. The specific targeting of PPT into the neuritic shafts and nerve terminals indicates that PPT may be associated with the maintenance of synaptic function. Furthermore, since a substantial amount of PPT is secreted by neurons, it is tempting to speculate that the enzyme could also have an extracellular substrate.

Adenoviridae↗
PubMed2000

Reduced mildly oxidized LDL in young female athletes.

We investigated the effect of physical activity and sports participation on LDL oxidation in vivo and on lipid risk factors in 183 teenage girls (9-15 years): 64 gymnasts, 61 runners, and 58 controls. Oxidized LDL was measured as baseline levels of conjugated dienes in LDL lipids (ox-LDL). The gymnasts had a 15% lower ratio of LDL conjugated dienes to LDL cholesterol (ox-LDL:LDL ratio, P = 0.0052) compared to controls, and the difference persisted when the body mass index was included as a covariate (ANCOVA, P = 0.013). Also, the gymnasts had a 12% higher ratio of HDL cholesterol to total cholesterol than the controls (ANCOVA, P = 0.046). There were no differences in the other common lipid risk factors between the groups. The ox-LDL:LDL ratio correlated negatively with HDL cholesterol (r = -0.23, P=0.0021) and with physical activity METs (multiples of resting metabolic rate) (r = -0.21, P=0.0040). Our study strengthens the evidence that the atherogenic risk is influenced favourably by physical exercise and sporting activities as early as in adolescents. This risk reduction is associated with lower mildly oxidized LDL in adolescent girls.

Adolescent↗
PubMed1999

Developmental expression of palmitoyl protein thioesterase in normal mice.

Deficiency in palmitoyl protein thioesterase (PPT) results in the rapid death of neocortical neurons in human. Very little is known about the developmental and cell-specific expression of this lysosomal enzyme. Here we show that PPT is expressed as a major 2.65 kb and a minor 1.85 kb transcript in the mouse brain. Transcript levels gradually increase between postnatal days 10 and 30. In situ hybridization analysis revealed that PPT transcripts are found widely but not homogeneously in the brain. The most intense signal was detected in the cerebral cortex (layers II, IV-V), hippocampal CA1-CA3 pyramidal cells, dentate gyrus granule cells and the hypothalamus. Immunostaining of PPT was localized in the cell soma, axons and dendrites, especially in the pyramidal and granular cells of the hippocampus, correlating well, both spatially and temporally, with the immunoreactivity of a presynaptic vesicle membrane protein, synaptophysin. In whole embryos, at embryonic day 8, the PPT mRNA expression was most apparent throughout the neuroepithelium, and from day 9 onwards it was seen in all tissues. The expression pattern of PPT suggests its general significance for the brain cells and reflects the response to maturation and growth of the neural networks. Strong PPT immunoreactivity in the axons and dentrites would imply that PPT may not be exclusively a lysosomal enzyme. A notable correlation with synaptophysin would suggest that PPT may have a role in the function of the synaptic machinery.

Aging↗
PubMed1999

Toward understanding the neuronal pathogenesis of aspartylglucosaminuria: expression of aspartylglucosaminidase in brain during development.

The deficiency of a lysosomal enzyme, aspartylglucosaminidase, results in a lysosomal storage disorder, aspartylglucosaminuria, manifesting as progressive mental retardation. To understand tissue pathogenesis and disease progression we analyzed the developmental expression of the enzyme, especially in brain, which is the major source of the pathological symptoms. Highest mRNA levels in brain were detected during embryogenesis, the levels decreased neonatally and started to increase again from Day 7 on. In Western analyses, a defective processing of aspartylglucosaminidase was observed in brain as compared to other tissues, resulting in very low levels of the mature, active form of the enzyme. Interestingly immunohistochemical analyses of mouse brain revealed that aspartylglucosaminidase immunoreactivity closely mimicked the myelin basic protein immunostaining pattern. The only evident neuronal staining was observed in the developing Purkinje cells of the cerebellum from Days 3 to 10, reflecting well the mRNA expression. In human infant brain, the immunostaining was also present in myelinated fibers as well as in the Purkinje cells and, additionally, in the soma and extensions of other neurons. In the adult human brain neurons and oligodendrocytes displayed immunoreactivity whereas myelinated fibers were not stained. Our results of aspartylglucosaminidase immunostaining in myelinated fibers of infant brain might imply the involvement of aspartylglucosaminidase in the early myelination process. This is consistent with previous magnetic resonance imaging findings in the brains of aspartylglucosaminuria patients, revealing delayed myelination in childhood.

Adult↗
PubMed1998

Expression and endocytosis of lysosomal aspartylglucosaminidase in mouse primary neurons.

Aspartylglucosaminuria (AGU) is a neurodegenerative lysosomal storage disease that is caused by mutations in the gene encoding for a soluble hydrolase, aspartylglucosaminidase (AGA). In this study, we have used our recently developed mouse model for AGU and analyzed processing, intracellular localization, and endocytosis of recombinant AGA in telencephalic AGU mouse neurons in vitro. The processing steps of AGA were found to be similar to the peripheral cells, but both the accumulation of the inactive precursor molecule and delayed lysosomal processing of the enzyme were detected. AGA was distributed to the cell soma and neuronal processes but was not found in the nerve terminals. Endocytotic capability of cultured telencephalic neurons was comparable to that of fibroblasts, and endocytosis of AGA was blocked by free mannose-6-phosphate (M6P), indicating that uptake of the enzyme was mediated by M6P receptors (M6PRs). Uptake of extracellular AGA was also studied in the tumor-derived cell lines rat pheochromocytoma (PC12) and mouse neuroblastoma cells (N18), which both endocytosed AGA poorly as compared with cultured primary neurons. Expression of cation-independent M6PRs (CI-M6PRs) in different cell lines correlated well with the endocytotic capability of these cells. Although a punctate expression pattern of CI-M6PRs was found in fibroblasts and cultured primary neurons, the expression was beyond the detection limit in PC12 and N18 cells. This indicates that PC12 and N18 are not feasible cell lines to describe neuronal uptake of mannose-6-phosphate-tagged proteins. This in vitro data will form an important basis for the brain-targeted therapy of AGU.

Animals↗
PubMed1998

Cells of the neuronal lineage play a major role in the generation of amyloid precursor fragments in gelsolin-related amyloidosis.

Gelsolin-related amyloidosis or familial amyloidosis, Finnish type (FAF) (OMIM No105120) is a hereditary amyloid disease caused by a mutation in a precursor protein for amyloid (gelsolin) and characterized by corneal dystrophy and polyneuropathy. In vitro expression of the FAF-mutant (Asp187 --> Asn/Tyr) secretory gelsolin in COS cells leads to generation of an aberrant polypeptide presumably representing the precursor for tissue amyloid. Here, we provide evidence that this abnormal processing results from defective initial folding of the secreted FAF gelsolin due to the lack of the Cys188-Cys201 disulfide bond, normally formed next to the FAF mutation site. We compared cells of different tissue origin and discovered a dramatic difference between the amount of cleavage of FAF gelsolin to the amyloid precursor in neuronal and non-neuronal cells. More than half of the mutant gelsolin was cleaved in PC12 and in vitro differentiated human neuronal progenitor cells. In contrast, human fibroblasts and Schwannoma cell cultures showed only a limited capacity to cleave FAF gelsolin, although the cleavage mechanism per se seems to be similar in the various cell types. The present findings of processing and distribution of secreted FAF gelsolin in the neuronal cells emphasize the role of neurons in the tissue pathogenesis of this amyloid polyneuropathy.

Amyloid Neuropathies↗
PubMed1998

Adenovirus-mediated gene transfer results in decreased lysosomal storage in brain and total correction in liver of aspartylglucosaminuria (AGU) mouse.

Aspartylglucosaminuria (AGU) is a lysosomal storage disease leading to mental retardation, which is caused by deficiency of aspartylglucosaminidase (AGA). AGU is strongly enriched in the Finnish population in which one major mutation called AGU(Fin) has been identified. The molecular pathogenesis of AGU as well as the biology of the AGA enzyme have been extensively studied, thus giving a profound basis for therapeutic interventions. In this study we have performed adenovirus-mediated gene transfer to the recently produced mouse model of AGU, which exhibits similar pathophysiology as that in humans. Recombinant adenovirus vectors encoding for the human AGA and AGU(Fin) polypeptides were first applied in primary neurons of AGU mouse to demonstrate wild-type and mutant AGA expression in vitro. In vivo, both of the adenovirus vectors were injected into the tail vein of AGU mice and the expression of AGA was demonstrated in the liver. The adenovirus vectors were also injected intraventricularly into the brain of AGU mice resulting in AGA expression in the ependymal cells lining the ventricles and further, diffusion of AGA into the neighbouring neurons. Also, AGA enzyme injected intraventricularly was shown to transfer across the ependymal cell layer. One month after administration of the wild-type Ad-AGA, a total correction of lysosomal storage in the liver and a partial correction in brain tissue surrounding the ventricles was observed. After administration of the Ad-AGU virus the lysosomal storage vacuoles in liver or brain remained unchanged. These data demonstrate that the lysosomal storage in AGU can be biologically corrected and furthermore, in the brain a limited number of transduced cells can distribute AGA enzyme to the surrounding areas.

Adenoviridae↗
PubMed1998

Incidence of cataract operations in Finnish male smokers unaffected by alpha tocopherol or beta carotene supplements.

OBJECTIVE: To examine the effect of alpha tocopherol and beta carotene supplementation on the incidence of age related cataract extraction. SETTING: The Alpha-tocopherol Beta-carotene (ATBC) Study was a randomised, double blind, placebo controlled, 2 x 2 factorial trial conducted in south western Finland. The cataract surgery study population of 28,934 male smokers 50-69 years of age at the start. INTERVENTION: Random assignment to one of four regimens: alpha tocopherol 50 mg per day, beta carotene 20 mg per day, both alpha tocopherol and beta carotene, or placebo. Follow up continued for five to eight years (median 5.7 years) with a total of 159,199 person years. OUTCOME MEASURE: Cataract extraction, ascertained from the National Hospital Discharge Registry. RESULTS: 425 men had cataract surgery because of senile or presenile cataract during the follow up. Of these, 112 men were in the alpha tocopherol alone group, 112 men in the beta carotene alone group, 96 men in the alpha tocopherol and beta carotene group, and 105 men in the placebo group. When supplementation with alpha tocopherol and with beta carotene were introduced to a Cox proportional hazards model with baseline characteristics (age, education, history of diabetes, body mass index, alcohol consumption, number of cigarettes smoked daily, smoking duration, visual acuity, and total cholesterol), neither alpha tocopherol (relative risk, RR, 0.91, 95% confidence intervals, CI, 0.74, 1.11) nor beta carotene (RR 0.97, 95% CI 0.79, 1.19) supplementation affected the incidence of cataract surgery. CONCLUSION: Supplementation with alpha tocopherol or beta carotene does not affect the incidence of cataract extractions among male smokers.

Aged↗
PubMed1998

Gyrate atrophy of the choroid and retina: lymphocyte ornithine-delta-aminotransferase activity in different mutations and carriers.

Deficiency of omithine-delta-aminotransferase (OAT) causes gyrate atrophy of the choroid and retina with hyperornithinemia (GA; McKusick 258870), a progressive autosomal recessive chorioretinal degeneration leading to early blindness. As residual enzyme activity may vary in different mutations of the OAT gene and explain individual variations in disease progression, a sensitive HPLC modification of the OAT assay in lymphocytes was developed, based on measurement of the dihydroquinozolinium reaction product. The OAT activities (ranges) of 43 Finnish GA patients with mutations L402P/L402P, R180T/L402P, N89K/ L402P, and L402P/x (x = previously unknown allele), were <1-10, <1-13, <1-17, and <1 pmol x min(-1) mg protein(-1), respectively. The OAT activities (mean+/-SD) of nine L402P/ wild heterozygotes were 70+/-50 (range 33-193), and those of 15 healthy control subjects 184+/-60 (range 85-291) pmol x min(-1) mg protein(-1). This lymphocyte assay is an easy, rapid, and sensitive method for reliable recognition of GA homozygotes. OAT mutations of the Finnish patients show similar residual enzyme activity in the lymphocytes. OAT activities in the L402P heterozygotes and healthy control subjects overlap, suggesting that, for reliable carrier detection, the OAT alleles have to be studied. However, as all OAT mutations are not known, direct measurement of enzyme activity has a role in heterozygote identification and possibly also in prenatal diagnosis of GA.

Adolescent↗
PubMed1997

Group II phospholipase A2 in serum after knee surgery and intramedullary nailing of tibial shaft fracture.

This prospective study investigates the effect of injury and surgery of cartilage and bone on serum group II phospholipase A2 (PLA2-II) and C-reactive protein (CRP) levels. Serum concentrations of PLA2-II and CRP were measured before and after the operation in nine patients with closed tibial shaft fractures treated by nailing, 11 patients with fractures of lateral tibial plateau treated by bone grafting, and 19 patients with ruptured anterior cruciate ligament treated by reconstruction. The postoperative PLA2-II and CRP values were statistically significantly higher than the pre-operative values in the tibial plateau fracture and ligament rupture groups, whereas the increase in the PLA2-II values in the tibial fracture group was not statistically significant. The highest values of both parameters were found on the second postoperative day. The changes in the PLA2-II and CRP values were parallel in the lateral condyle fracture and in anterior cruciate ligament rupture groups. PLA2-II behaves as an acute phase reactant in the serum of patients undergoing acute and elective knee surgery.

Acute-Phase Proteins↗
PubMed1996

Apolipoprotein E (apoE) levels in brains from Alzheimer disease patients and controls.

We measured apolipoprotein E (apoE) level in neutral and acidic pH extracts of the frontal, temporal and cerebellar cortices from patients with definite Alzheimer's disease (AD) and controls, and analyzed the relationship among apoE levels, clinical and neuropathological findings, and apoE genotype. Our data showed that the levels varied in different brain regions being lowest in the frontal cortex and highest in the cerebellum in Ad brains. ApoE levels in neutral pH extracts from the frontal cortex from AD patients were significantly lower than those of controls, and correlated negatively with the number of neurofibrillary tangles. ApoE genotype was not associated with the levels of apoE. There was no correlation between apoE levels and amyloid load or synaptophysin-immunoreactivity in the brain. We conclude that apoE levels are not increased in AD brains. However, apoE levels vary in different brain regions, and local factors related to the synthesis and metabolism of apoE may be crucial in the pathogenesis of AD.

Aged↗
PubMed1996

Apolipoprotein E polymorphism in patients with different neurodegenerative disorders.

Apolipoprotein E (ApoE) is associated with Alzheimer's disease (AD) neurofibrillary tangles and beta-amyloid protein in senile plaques. There are three common alleles of ApoE, designated epsilon 2, epsilon 3 and epsilon 4. We studied Finnish patients with neurodegenerative disorders: AD, vascular dementia (VAD), Parkinson's disease (PD), PD+dementia (PDD), Lewy body variant of AD (LB), frontal dementia (FD), and Down's syndrome (DS), as well as control individuals (C). The ApoE genotypes and corresponding allele frequencies of 188 patients and 60 controls were determined by digestion of ApoE polymerase chain reaction products with the restriction enzyme Hha I. The ApoE epsilon 4 allele frequency was 0.17 for C, 0.44 for AD, 0.35 for VAD, 0.10 for PD, 0.38 for PDD, 0.28 for LB, 0.39 for FD, and 0.17 for DS. We found significant differences in genotype frequency between AD/C, AD/PD and AD/DS. Our results suggest that, beside AD, an increased frequency of epsilon 4 may also be involved in other dementing neurological disorders.

Adult↗
PubMed1996

Cerebrospinal fluid concentrations of soluble amyloid beta-protein and apolipoprotein E in patients with Alzheimer's disease: correlations with amyloid load in the brain.

OBJECTIVE: To compare soluble amyloid beta-protein and apolipoprotein E levels in cerebrospinal fluid (CSF) and brain extracts from patients with definite Alzheimer's disease. SETTING: University medical center. PATIENTS: Nineteen patients with definite Alzheimer's disease. MAIN OUTCOME MEASURES: Soluble amyloid beta-protein and apolipoprotein E levels in CSF, in neutral and low-pH brain extracts, and in formic acid-treated sections of the frontal, temporal, and cerebellar cortices, measured using enzyme-linked immunosorbent assay. RESULTS: Soluble amyloid beta-protein and apolipoprotein E levels in CSF were significantly lower in patients with congophilic angiopathy than in those without angiopathy. The levels did not correlate with the number of amyloid plaques in the neocortex. There was, however, a tendency toward an inverse correlation between the amount of amyloid beta-protein in the frontal cortex extracts and the soluble amyloid beta-protein level in CSF. CONCLUSION: Soluble amyloid beta-protein levels in CSF may reflect amyloid accumulation in brain blood vessels.

Aged↗
PubMed1996

Diagnostic accuracy of Alzheimer's disease: a neuropathological study.

This prospective study focused on the accuracy of diagnosis of Alzheimer's disease (AD). We recruited 100 dementia patients and 20 controls who underwent a systematic evaluation. The clinical diagnosis of probable AD or possible AD according to the NINCDS-ADRDA criteria was assigned in 69% of the patients, 21% had vascular dementia (VaD) (DSM-III-R) and 8% had mixed AD-VaD; only 2 patients (2%) had the Lewy body variant of AD (AD-LB). During a 3-year period 57 patients died, 53 of them (93%) being autopsied. Neuropathological examination according to the CERAD criteria showed definite AD in 27 out of 28 (96%) patients diagnosed as probable AD. In the possible AD group, the diagnostic accuracy was also high, 86% showed at least some degree of AD pathological alterations. The neocortical senile plaque scores correlated significantly with tangle scores in patients with AD pathology, and there was a significant negative correlation between age of onset and neocortical tangle scores. The concordance between the clinical diagnosis and pathological findings was clearly lower in VaD than in AD. In the clinical VaD group, 8 of 10 patients had at least some degree of AD changes together with vascular changes and only 2 of 10 patients had pure VaD. This study confirms the high accuracy of the NINCDS-ADRDA criteria for diagnosing AD. In contrast, uncertainty in the clinical diagnosis of VaD should be taken into account, for example, in drug trials with VaD patients.

Age of Onset↗