Biomedical subjects

K Yasojima

Publications and source records attributed to K Yasojima.

31 records · Page 2Linked to original sources

PubMed1999

Complement regulators C1 inhibitor and CD59 do not significantly inhibit complement activation in Alzheimer disease.

Proteins characteristic of activated complement are associated with Alzheimer disease (AD) lesions. The classical complement pathway can be activated only when the influence of such endogenous regulators as C1-inhibitor (C1-inh) and CD59 are overcome. We used the techniques of reverse transcriptase-polymerase chain reaction and Western blotting to assess the mRNA and protein levels of C1-inh and CD59 in AD and control brains in comparison with levels of the complement components with which they interact. The inhibitors were only slightly upregulated and then only in heavily affected areas of AD brain such as the entorhinal cortex, hippocampus, midtemporal gyrus and midfrontal gyrus. The ratio of AD to control mRNAs in these four areas was 1.17 for C1-inh and 1.12 for CD59, compared to 3.06 for C1r, 2.67 for C1s, 2.35 for C5, 2.56 for C6, 2.42 for C7, 5. 08 for C8 and 16.3 for C9. Peripheral organ expression of C1-inh and CD59 mRNAs was no different in AD than controls but was slightly upregulated in infarcted heart tissue. Again, the increase was small compared with that of the competitive complement components. These data indicate that the forces which upregulate and activate complement in AD and myocardial infarction are not effectively suppressed by the endogenous regulators, C1-inh and CD59.

Adult↗

PubMed1999

Tangled areas of Alzheimer brain have upregulated levels of exon 10 containing tau mRNA.

We measured the relative levels of exon 10 containing and exon 10 deleted tau mRNAs in multiple areas of Alzheimer disease (AD) and normal brain. Compared with normal brain, we found a 3.4-fold upregulation of exon 10 plus and a 1.9-fold downregulation of exon 10 minus mRNAs in areas of AD brain with a heavy burden of neurofibrillary tangles. These data suggest that tangle formation in AD is initially determined by transcriptional factors and is not exclusively caused by post-translational events.

Adult↗

PubMed1999

Distribution of cyclooxygenase-1 and cyclooxygenase-2 mRNAs and proteins in human brain and peripheral organs.

We used the techniques of reverse transcriptase-polymerase chain reaction, Western blotting and immunohistochemistry to evaluate the expression of cyclooxygenase (COX)-1 and -2 in brain and peripheral organs of Alzheimer disease (AD) and control cases. We found both COX-1 and COX-2 to be constitutively expressed in all organs tested, i.e., brain, heart, liver, kidney, spleen and intestine. COX-2 was substantially upregulated in affected areas of AD brain and in infarcted areas of human heart. COX-1 was only mildly upregulated in AD brain. Immunohistochemically, COX-2 was strongly expressed in the perinuclear, dendritic and axonal areas of pyramidal neurons, with enhanced staining in AD. These data suggest a special role for COX-2 in neuronal function.

Adult↗

PubMed1999

Up-regulated production and activation of the complement system in Alzheimer's disease brain.

We used reverse transcriptase-polymerase chain reaction and Western blotting techniques to measure the levels of complement mRNAs and their protein products in Alzheimer's disease (AD) brain compared with non-AD brain. mRNAs for C1q, C1r, C1s, C2, C3, C4, C5, C6, C7, C8, and C9 were detected in the 11 regions of brain that were investigated. The mRNA levels were markedly up-regulated in affected areas of AD brain. In the entorhinal cortex, hippocampus, and midtemporal gyrus, which had dense accumulations of plaques and tangles, C1q mRNA was increased 11- to 80-fold over control levels, and C9 mRNA 10- to 27-fold. These levels were substantially higher than in the livers of the same cases. Western blot analysis of AD hippocampus established the presence of all of the native complement proteins as well as their activation products C4d, C3d, and the membrane attack complex. These data indicate that high levels of complement are being produced in affected areas of AD brain, that full activation of the classical complement pathway is continuously taking place, and that this activation may be contributing significantly to AD pathology.

Adult↗

PubMed1999

Preconditioning reduces tissue complement gene expression in the rabbit isolated heart.

Both preconditioning and inhibition of complement activation have been shown to ameliorate myocardial ischemia-reperfusion injury. The recent demonstration that myocardial tissue expresses complement components led us to investigate whether preconditioning affects complement expression in the isolated heart. Hearts from New Zealand White rabbits were exposed to either two rounds of 5 min global ischemia followed by 10 min reperfusion (ischemic preconditioning) or 10 microM of the ATP-dependent K+ (KATP) channel opener pinacidil for 30 min (chemical preconditioning) before induction of 30 min global ischemia followed by 60 min of reperfusion. Both ischemic and chemical preconditioning significantly (P < 0.05) reduced myocardial C1q, C1r, C3, C8, and C9 mRNA levels. Western blot and immunohistochemistry demonstrated a similar reduction in C3 and membrane attack complex protein expression. The K(ATP) channel blocker glyburide (10 microM) reversed the depression of C1q, C1r, C3, C8, and C9 mRNA expression observed in the pinacidil-treated hearts. The results suggest that reduction of local tissue complement production may be one means by which preconditioning protects the ischemic myocardium.

Animals↗

PubMed1998

Human heart generates complement proteins that are upregulated and activated after myocardial infarction.

In human heart, we detected mRNAs and proteins for C1q, C1r, C1s, C2, C3, C4, C5, C6, C7, C8, and C9 with the use of reverse transcriptase-polymerase chain reaction, Western blotting, and immunohistochemical techniques. We found an upregulation of both mRNAs and proteins in areas of recent and old myocardial infarctions. In both situations, the classical complement pathway was activated, with C4d, C3d, and the membrane attack complex (C5b-9) being deposited on damaged cardiac myocytes. These activated complement components were also identified on Western blots of infarcted tissue. Complement mRNAs in infarcted heart tissue were higher than those in liver, and liver complement mRNAs were not upregulated in cases with infarcted hearts. Our results establish that (1) complement proteins are endogenously produced by human heart; (2) the classical complement pathway is fully activated after myocardial infarction; (3) complement activation is directly involved in myocardial damage after ischemic insults; and (4) damage from complement activation may be chronically sustained. These data suggest that inhibition of the complement system should be effective in treating myocardial infarction.

Adult↗

PubMed1998

Complement gene expression by rabbit heart: upregulation by ischemia and reperfusion.

Activation of the complement system has been implicated in the pathogenesis of myocardial ischemia/reperfusion injury. It has always been assumed that liver is the primary source of complement components. In the present study, we used the reverse-transcriptase polymerase chain reaction technique to establish that the mRNAs for complement proteins C3 and C9 are expressed in rabbit heart. Rabbit liver, brain, spleen, and kidney were also shown to express C3 and C9 mRNAs. We used Western blotting to establish that these mRNAs in heart are translated into the corresponding proteins. We further established that dramatic upregulation of the mRNAs occurred in Langendorff-perfused isolated hearts subjected to ischemia and reperfusion. C3 mRNA was always expressed at higher levels than was C9 mRNA, but C9 mRNA showed greater upregulation under stress. Compared with levels in control hearts subjected to 5 minutes of normoxic perfusion, hearts subjected to 0.5 hours of ischemia followed by 1 hour of reperfusion had a 4.72-fold increase in C3 mRNA and a 19.5-fold increase in C9 mRNA. By contrast, C3 mRNA in hearts subjected to 3.5 hours of normoxic perfusion showed no change, and those subjected to 3.5 hours of ischemia showed only a 1.72-fold increase, whereas C9 mRNA levels increased by 5.17-fold after 3.5 hours of normoxic perfusion and 12.5-fold after 3.5 hours of ischemia. The results of this study demonstrate for the first time that heart tissue is capable of expressing genes and proteins of the complement system, although it is not yet known which cell types are responsible. They further demonstrate that ischemia and reperfusion of the heart promotes a rapid upregulation of the mRNAs encoding the complement proteins C3 and C9 and that these abnormal levels considerably exceed those of normal liver. These observations are consistent with the hypothesis that local production of complement proteins may contribute significantly to the degree of ischemic injury to the myocardium and that complement expression is augmented by reperfusion.

Animals↗

PubMed1997

Cloning of human and mouse cDNAs encoding novel zinc finger proteins expressed in cerebellum and hippocampus.

We identified a novel gene, kf-1, highly expressed in the normal cerebellum but not in the cerebral cortex, the expression of which could have been augmented in the cerebral cortex of a sporadic Alzheimer's disease patient. We cloned human and mouse entire kf-1 cDNAs encoding conserved 79 kDa proteins containing a zinc-binding RING-H2 finger motif at the carboxy-terminus as found in acetylcholine receptor-associated protein (RAPsyn). The 3'-untranslated regions are highly conserved between human and mouse as to constitute a common mRNA secondary structure. In situ hybridization analysis of mouse brain sections revealed strong kf-1 expression in the cerebellum and hippocampus. We propose that KF-1 is involved in membranous protein-sorting apparatus similarly to RAPsyn. We mapped the human kf-1 gene to 2p11.2.

Alzheimer Disease↗

PubMed1997

Cloning of Xenopus presenilin-alpha and -beta cDNAs and their differential expression in oogenesis and embryogenesis.

Human presenilin (ps)-1 and -2 genes have recently been shown to be involved in genesis of early-onset familial Alzheimer's disease. By probing with human (H-) ps-1 cDNA, we isolated two types of cDNA clones, named X-ps-alpha and -beta, from a Xenopus brain cDNA library. The encoded proteins, X-PS-alpha and -beta, may correspond to H-PS-1 and -2 with 89.4 and 85.9% similarity, respectively. The strongest expression of these genes was observed in ovaries and in the early stages of oogenesis, although weak or moderate expression was detected ubiquitously for both X-ps-alpha and -beta genes in multiple tissues. Upon oocyte maturation, the X-ps-beta mRNA level was constant even after fertilization until the midblastula transition. Zygotic expression of these genes became evident only at the tailbud stage. We propose that presenilins may function in preventing cells from undergoing apoptotic degeneration particularly prior to embryonic development and in developmentally matured tissues.

Amino Acid Sequence↗

PubMed1995

Plasmids with a kanamycin-resistance gene for site-directed mutagenesis using the oligodeoxyribonucleotide-directed dual amber method.

Plasmid vectors carrying lacZ' and kanamycin-resistance (KmR) genes were constructed for site-directed mutagenesis (SDM) using the oligodeoxyribonucleotide (oligo)-directed dual amber (ODA) method [Hashimoto-Gotoh et al., Gene 152 (1995) 271-276]. The plasmids, designated pKF16k, pKF17k, pKF18k and pKF19k, correspond to the previously reported chloramphenicol resistant (CmR) ODA plasmids, pKF16c, pKF17c, pKF18c and pKF19c, respectively, but contain dual amber (am) codons in KmR instead of the CmR gene. The SDM procedure using the KmR ODA plasmids is essentially the same as that with CmR ODA plasmids, which utilizes two oligo primers for in vitro DNA synthesis, one (selection primer) for dual am reversions and the other (mutagenic primer) for the target site. The KmR ODA plasmids yield 5-10-times more DNA per culture volume as compared to the CmR ODA plasmids, and one can prepare selection agar medium simply by spreading Km solution on dried agar plate at a final concentration of 50-100 micrograms/ml; due to the broad range of selecting antibiotic resistance.

Base Sequence↗

PubMed1995

Developmental and differential regulations in gene expression of Xenopus pleiotrophic factors-alpha and -beta.

Using conserved nucleotide sequences in mammalian osteoblast specific factor-1 (OSF-1) coding regions, we isolated two kinds of cDNA clones from the Xenopus brain library. The encoded proteins, named Xenopus pleiotrophic factors (X-PTFs)-alpha and -beta, were 65 and 87% homologous to human midkine and OSF-1, respectively. In the adult frog, X-ptf-alpha was expressed in the ovary, brain, eye, bone, heart and lung, whereas X-ptf-beta was expressed in the brain, eye and bone. By in situ hybridization of the tailbud embryo, X-ptf-alpha mRNA was detected rather broadly in the head/tail regions including the central nervous system (CNS), whereas X-ptf-beta mRNA was restricted to the CNS, particularly in the hind-brain. During embryogenesis, X-ptf-alpha mRNA was detected in the one-cell stage embryo, whereas only zygotic expression was observed in X-ptf-beta. X-ptf-beta mRNAs contained approximately 79 bp tandem repeats in the 3'-untranslated region, complementary to those found in retinoic acid cellular receptor mRNA and in the sense strand of short interspersed repeat transcripts in X. laevis.

Aging↗

PubMed1995

[Alexia-agraphia of kanji (Japanese morphogram) after left posterior-inferior temporal lesion].

Several cases of selective alexia with agraphia of kanji have been reported in Japan in this decade. It is well known that the lesion in the posterior inferior temporal lobe of the dominant hemisphere is responsible for this cognitive syndrome. Neuropsychological data in our patient suggest that the postero-inferior region of the temporal lobe of the dominant hemisphere may be the visuo-verbal association area for the analysis of the complex visuo-verbal information. The symptoms caused by the same lesion in western patients might be subangular alexia (alexia without agraphia). Alexia with agraphia of kanji and subangular alexia would appear to be distinct entities, but a dual processing hypothesis of visuo-verbal information and the concept of the visuo-verbal association area might well explain both syndromes.

Agraphia↗

PubMedDate not supplied

The pentraxins: possible role in Alzheimer's disease and other innate inflammatory diseases.

Two short pentraxins, C-reactive protein and amyloid P, are found in association with the senile plaques and neurofibrillary tangles of Alzheimer disease (AD). Formerly thought to be made primarily if not solely in liver, recent work has shown that they are made not only in the brain but in other tissues such as heart and arteries. Their synthesis is markedly upregulated in affected brain regions in AD. Since they are known to activate the complement cascade in an antibody-independent fashion and chronic activation can cause destruction of host tissue, these pentraxins may be important initiators of an autodestructive process. As such, they may be prime targets for therapeutic intervention.

Acute-Phase Proteins↗