ABSTRACT
Generation and accumulation of amyloid-ß (Aß) protein in the brain are the primary causes of Alzheimer's disease (AD). Alcadeins (Alcs composed of Alcα, Alcß and Alcγ family) are a neuronal membrane protein that is subject to proteolytic processing, as is Aß protein precursor (APP), by APP secretases. Previous observations suggest that Alcs are involved in the pathophysiology of Alzheimer's disease (AD). Here, we generated new mouse AppNL-F (APP-KI) lines with either Alcα- or Alcß-deficient background and analyzed APP processing and Aß accumulation through the aging process. The Alcα-deficient APP-KI (APP-KI/Alcα-KO) mice enhanced brain Aß accumulation along with increased amyloidogenic ß-site cleavage of APP through the aging process whereas Alcß-deficient APP-KI (APP-KI/Alcß-KO) mice neither affected APP metabolism nor Aß accumulation at any age. More colocalization of APP and BACE1 was observed in the endolysosomal pathway in neurons of APP-KI/Alcα-KO mice compared to APP-KI and APP-KI/Alcß-KO mice. These results indicate that Alcα plays an important role in the neuroprotective function by suppressing the amyloidogenic cleavage of APP by BACE1 in the brain, which is distinct from the neuroprotective function of Alcß, in which p3-Alcß peptides derived from Alcß restores the viability in neurons impaired by toxic Aß.
Subject(s)
Aging , Amyloid Precursor Protein Secretases , Amyloid beta-Peptides , Amyloid beta-Protein Precursor , Brain , Animals , Mice , Aging/metabolism , Alzheimer Disease/metabolism , Alzheimer Disease/genetics , Amyloid beta-Peptides/metabolism , Amyloid beta-Protein Precursor/metabolism , Amyloid beta-Protein Precursor/genetics , Amyloid Precursor Protein Secretases/metabolism , Aspartic Acid Endopeptidases/metabolism , Aspartic Acid Endopeptidases/genetics , Brain/metabolism , Calcium-Binding Proteins/metabolism , Calcium-Binding Proteins/genetics , Mice, Knockout , Nerve Tissue Proteins/metabolism , Nerve Tissue Proteins/genetics , Neurons/metabolismABSTRACT
Alcadein α (Alcα) and amyloid-ß protein precursor (APP) are cargo receptors that associate vesicles with kinesin-1. These vesicles, which contain either Alcα or APP, transport various proteins/cargo molecules into axon nerve terminals. Here, we analyzed immune-isolated Alcα- and APP-containing vesicles of adult mouse brains with LC-MS/MS and identified proteins present in vesicles that contained either Alcα or APP. Among these proteins, Frizzled-5 (Fzd5), a Wnt receptor, was detected mainly in Alcα vesicles. Although colocalization ratios of Fzd5 with Alcα are low in the neurites of differentiating neurons by a low expression of Fzd5 in embryonic brains, the suppression of Alcα expression decreased the localization of Fzd5 in neurites of primary cultured neurons. Furthermore, Fzd5-EGFP expressed in primary cultured neurons was preferentially transported in axons with the transport velocities of Alcα vesicles. In synaptosomal fractions of adult-mice brains that express higher levels of Fzd5, the amount of Fzd5 and the phosphorylation level of calcium/calmodulin-dependent protein kinase-II were reduced in the Alcα-deficient mice. These results suggest that reduced transport of Fzd5 by Alcα-containing vesicles associated with kinesin-1 in axon terminals may impair the response to Wnt ligands in the noncanonical Ca2+-dependent signal transduction pathway at nerve terminals of mature neurons.
Subject(s)
Axonal Transport , Kinesins , Animals , Mice , Amyloid beta-Protein Precursor/metabolism , Axonal Transport/physiology , Chromatography, Liquid , Kinesins/metabolism , Tandem Mass SpectrometryABSTRACT
We propose a new therapeutic strategy for Alzheimer's disease (AD). Brain peptide p3-Alcß37 is generated from the neuronal protein alcadein ß through cleavage of γ-secretase, similar to the generation of amyloid ß (Aß) derived from Aß-protein precursor/APP. Neurotoxicity by Aß oligomers (Aßo) is the prime cause prior to the loss of brain function in AD. We found that p3-Alcß37 and its shorter peptide p3-Alcß9-19 enhanced the mitochondrial activity of neurons and protected neurons against Aßo-induced toxicity. This is due to the suppression of the Aßo-mediated excessive Ca2+ influx into neurons by p3-Alcß. Successful transfer of p3-Alcß9-19 into the brain following peripheral administration improved the mitochondrial viability in the brain of AD mice model, in which the mitochondrial activity is attenuated by increasing the neurotoxic human Aß42 burden, as revealed through brain PET imaging to monitor mitochondrial function. Because mitochondrial dysfunction is common in the brain of AD patients alongside increased Aß and reduced p3-Alcß37 levels, the administration of p3-Alcß9-19 may be a promising treatment for restoring, protecting, and promoting brain functions in patients with AD.
Subject(s)
Alzheimer Disease , Amyloid beta-Peptides , Mice , Animals , Humans , Amyloid beta-Peptides/metabolism , Alzheimer Disease/drug therapy , Alzheimer Disease/metabolism , Amyloid beta-Protein Precursor/genetics , Amyloid beta-Protein Precursor/metabolism , Brain/metabolism , Neurons/metabolism , Amyloid Precursor Protein Secretases/metabolismABSTRACT
Apolipoprotein E4 (apoE4) is a risk factor for Alzheimer's disease (AD). Here, we investigated brain amyloid-ß (Aß) accumulation throughout the aging process in an amyloid precursor protein (APP) knock-in (KI) mouse model of AD that expresses human APPNL-G-F with or without human apoE4 or apoE3. Brain Aß42 levels were significantly lower in 9-month-old mice that express human isoforms of apoE than in age-matched APP-KI control mice. Linear accumulation of Aß42 began in 5-month-old apoE4 mice, and a strong increase in Aß42 levels was observed in 21-month-old apoE3 mice. Aß42 levels in cerebroventricular fluid were higher in apoE3 than in apoE4 mice at 6-7 months of age, suggesting that apoE3 is more efficient at clearing Aß42 than apoE4 at these ages. However, apoE3 protein levels were lower than apoE4 protein levels in the brains of 21-month-old apoE3 and apoE4 mice, respectively, which may explain the rapid increase in brain Aß42 burden in apoE3 mice. We identified genes that were downregulated in a human apoE-dependent (apoE4 > apoE3) and age-dependent (apoE3 = apoE4) manner, which may regulate brain Aß burden and/or AD progression. Analysis of gene expression in AD mouse models helps identify molecular mechanisms of pleiotropy by the human APOE gene during aging.
Subject(s)
Alzheimer Disease , Humans , Mice , Animals , Alzheimer Disease/metabolism , Apolipoprotein E4/genetics , Apolipoprotein E4/metabolism , Apolipoprotein E3/genetics , Apolipoprotein E3/metabolism , Mice, Transgenic , Apolipoproteins E/metabolism , Amyloid beta-Peptides/metabolism , Amyloid beta-Protein Precursor/genetics , Amyloid beta-Protein Precursor/metabolism , Brain/metabolism , Aging/genetics , Aging/metabolism , Protein Isoforms/genetics , Protein Isoforms/metabolism , Gene ExpressionABSTRACT
γ-Secretase cleaves type I transmembrane proteins in a hydrophobic membrane environment following ectodomain shedding. Mutations in PSEN genes, encoding the catalytic subunits of γ-secretase, presenilins, are the most common cause of familial Alzheimer's disease (ad). Pathogenic mutations in PSEN genes increase production of longer and neurotoxic amyloid-ß (Aß) by intramembrane cleavage of membrane-associated amyloid-ß protein precursor (APP) carboxyl-terminal fragment ß, which is generated via primary cleavage of APP by ß-site APP cleaving enzyme 1. The longer Aß is prone to aggregate and accumulate in the brain; however, the accumulation of Aß in brain is also a pathological feature of sporadic ad. Increased pathogenic Aß generation, even in the absence of pathogenic PSEN gene mutations, is one of proposed mechanisms for sporadic ad pathogenesis. γ-Secretase digests substrates in the transmembrane region, generating Aß peptide intermediates of various lengths. The end products, shorter Aß40 and Aß38 peptides, are less neurotoxic, whereas PSEN gene mutations increase the production ratio of longer, neurotoxic Aß species such as Aß42, an intermediate in Aß38 production. γ-Secretase activity or structures is altered because of its aberrant membrane localization or changes in the ambient environment such as luminal acidification. Interestingly, γ-secretase has a pH sensor in presenilins.
Subject(s)
Alzheimer Disease , Amyloid Precursor Protein Secretases , Alzheimer Disease/metabolism , Amyloid Precursor Protein Secretases/genetics , Amyloid Precursor Protein Secretases/metabolism , Amyloid beta-Peptides/metabolism , Amyloid beta-Protein Precursor/genetics , Amyloid beta-Protein Precursor/metabolism , Humans , Membrane Proteins/genetics , Mutation , Protein DomainsABSTRACT
Two common conjugated linoleic acids (LAs), cis-9, trans-11 CLA (c9,t11 CLA) and trans-10, cis-12 CLA (t10,c12 CLA), exert various biological activities. However, the effect of CLA on the generation of neurotoxic amyloid-ß (Aß) protein remains unclear. We found that c9,t11 CLA significantly suppressed the generation of Aß in mouse neurons. CLA treatment did not affect the level of ß-site APP-cleaving enzyme 1 (BACE1), a component of active γ-secretase complex presenilin 1 amino-terminal fragment, or Aß protein precursor (APP) in cultured neurons. BACE1 and γ-secretase activities were not directly affected by c9,t11 CLA. Localization of BACE1 and APP in early endosomes increased in neurons treated with c9,t11 CLA; concomitantly, the localization of both proteins was reduced in late endosomes, the predominant site of APP cleavage by BACE1. The level of CLA-containing phosphatidylcholine (CLA-PC) increased dramatically in neurons incubated with CLA. Incorporation of phospholipids containing c9,t11 CLA, but not t10,c12 CLA, into the membrane may affect the localization of some membrane-associated proteins in intracellular membrane compartments. Thus, in neurons treated with c9,t11 CLA, reduced colocalization of APP with BACE1 in late endosomes may decrease APP cleavage by BACE1 and subsequent Aß generation. Our findings suggest that the accumulation of c9,t11 CLA-PC/LPC in neuronal membranes suppresses the production of neurotoxic Aß in neurons.
Subject(s)
Amyloid beta-Peptides/biosynthesis , Linoleic Acid/pharmacology , Linoleic Acids, Conjugated/pharmacology , Neurons/metabolism , Amyloid Precursor Protein Secretases/metabolism , Amyloid beta-Peptides/toxicity , Amyloid beta-Protein Precursor/metabolism , Animals , Aspartic Acid Endopeptidases/metabolism , Cells, Cultured , Dietary Supplements , Endosomes/drug effects , Endosomes/metabolism , Immunohistochemistry , Male , Mice , Mice, Inbred C57BL , Neurons/drug effects , Phosphatidylcholines/metabolismABSTRACT
BACKGROUND: Brain amyloid-ß (Aß) peptide is released into the interstitial fluid (ISF) in a neuronal activity-dependent manner, and Aß deposition in Alzheimer's disease (AD) is linked to baseline neuronal activity. Although the intrinsic mechanism for Aß generation remains to be elucidated, interleukin-like epithelial-mesenchymal transition inducer (ILEI) is a candidate for an endogenous Aß suppressor. OBJECTIVE: This study aimed to access the mechanism underlying ILEI secretion and its effect on Aß production in the brain. METHODS: ILEI and Aß levels in the cerebral cortex were monitored using a newly developed ILEI-specific ELISA and in vivo microdialysis in mutant human Aß precursor protein-knockin mice. ILEI levels in autopsied brains and cerebrospinal fluid (CSF) were measured using ELISA. RESULTS: Extracellular release of ILEI and Aß was dependent on neuronal activation and specifically on tetanus toxin-sensitive exocytosis of synaptic vesicles. However, simultaneous monitoring of extracellular ILEI and Aß revealed that a spontaneous fluctuation of ILEI levels appeared to inversely mirror that of Aß levels. Selective activation and inhibition of synaptic receptors differentially altered these levels. The evoked activation of AMPA-type receptors resulted in opposing changes to ILEI and Aß levels. Brain ILEI levels were selectively decreased in AD. CSF ILEI concentration correlated with that of Aß and were reduced in AD and mild cognitive impairment. CONCLUSION: ILEI and Aß are released from distinct subpopulations of synaptic terminals in an activity-dependent manner, and ILEI negatively regulates Aß production in specific synapse types. CSF ILEI might represent a surrogate marker for the accumulation of brain Aß.
Subject(s)
Amyloid beta-Protein Precursor/metabolism , Cytokines/genetics , Cytokines/metabolism , Neoplasm Proteins/genetics , Neoplasm Proteins/metabolism , Synapses , Aged , Aged, 80 and over , Amyloid beta-Protein Precursor/genetics , Animals , Autopsy , Cerebral Cortex/metabolism , Cytokines/cerebrospinal fluid , Extracellular Space/metabolism , Female , Gene Knock-In Techniques , Genes, Suppressor , Humans , Male , Mice , Mice, Inbred C57BL , Microdialysis , Motor Activity , Neoplasm Proteins/cerebrospinal fluid , Receptors, AMPA/metabolism , Receptors, GABA/metabolismABSTRACT
Alzheimer's disease (AD) is a very common neurodegenerative disorder, chiefly caused by increased production of neurotoxic ß-amyloid (Aß) peptide generated from proteolytic cleavage of ß-amyloid protein precursor (APP). Except for familial AD arising from mutations in the APP and presenilin (PSEN) genes, the molecular mechanisms regulating the amyloidogenic processing of APP are largely unclear. Alcadein α/calsyntenin1 (ALCα/CLSTN1) is a neuronal type I transmembrane protein that forms a complex with APP, mediated by the neuronal adaptor protein X11-like (X11L or MINT2). Formation of the ALCα-X11L-APP tripartite complex suppresses Aß generation in vitro, and X11L-deficient mice exhibit enhanced amyloidogenic processing of endogenous APP. However, the role of ALCα in APP metabolism in vivo remains unclear. Here, by generating ALCα-deficient mice and using immunohistochemistry, immunoblotting, and co-immunoprecipitation analyses, we verified the role of ALCα in the suppression of amyloidogenic processing of endogenous APP in vivo We observed that ALCα deficiency attenuates the association of X11L with APP, significantly enhances amyloidogenic ß-site cleavage of APP, especially in endosomes, and increases the generation of endogenous Aß in the brain. Furthermore, we noted amyloid plaque formation in the brains of human APP-transgenic mice in an ALCα-deficient background. These results unveil a potential role of ALCα in protecting cerebral neurons from Aß-dependent pathogenicity in AD.
Subject(s)
Alzheimer Disease/metabolism , Amyloid beta-Protein Precursor/metabolism , Brain/metabolism , Calcium-Binding Proteins/deficiency , Multiprotein Complexes/metabolism , Protein Processing, Post-Translational , Alzheimer Disease/genetics , Alzheimer Disease/pathology , Amyloid beta-Protein Precursor/genetics , Animals , Brain/pathology , Calcium-Binding Proteins/metabolism , Carrier Proteins/genetics , Carrier Proteins/metabolism , Mice , Mice, Knockout , Multiprotein Complexes/genetics , Nerve Tissue Proteins/genetics , Nerve Tissue Proteins/metabolism , Presenilin-1/genetics , Presenilin-1/metabolismABSTRACT
Amyloid ß-proteins (Aßs) Aß1-42 and Aß1-43 are converted via two product lines of γ-secretase to Aß1-38 and Aß1-40. This parallel stepwise processing model of γ-secretase predicts that Aß1-42 and Aß1-43, and Aß1-38 and Aß1-40 are proportional to each other, respectively. To obtain further insight into the mechanisms of parenchymal Aß deposition, these four Aß species were quantified in insoluble fractions of human brains (Brodmann areas 9 to 11) at various Braak senile plaque (SP) stages, using specific enzyme-linked immunosorbent assays. With advancing SP stages, the amounts of deposited Aß1-43 in the brain increased proportionally to those of Aß1-42. Similarly, the amounts of deposited Aß1-38 correlated with those of Aß1-40. Surprisingly, the ratios of deposited Aß1-38/Aß1-42 and Aß1-40/Aß1-43 were proportional and discriminated the Braak SP stages accurately. This result indicates that the generation of Aß1-38 and Aß1-40 decreased and the generation of Aß1-42 and Aß1-43 increased with advancing SP stages. Thus, Aßs deposition might depend on γ-secretase activity, as it does in the cerebrospinal fluid. Here, the extracted γ-secretase from Alzheimer disease brains generates an amount of Aß1-42 and Aß1-43 compared with cognitively normal brains. This refractory γ-secretase localized in detergent-solubilized fractions from brain cortices. But activity modulated γ-secretase, which decreases Aß1-42 and Aß1-43 in the cerebrospinal fluid, localized in detergent-insoluble fractions. These drastic alterations reflect Aß situation in Alzheimer disease brains.
Subject(s)
Alzheimer Disease/metabolism , Amyloid Precursor Protein Secretases/metabolism , Brain/metabolism , Plaque, Amyloid/metabolism , Aged , Aged, 80 and over , Alzheimer Disease/pathology , Amyloid beta-Peptides/metabolism , Amyloid beta-Protein Precursor/metabolism , Brain/pathology , Disease Progression , Female , Humans , Male , Plaque, Amyloid/pathologyABSTRACT
A neuropathologic hallmark of Alzheimer's disease (AD) is the presence of senile plaques that contain neurotoxic amyloid-ß protein (Aß) species, which are generated by the cleavage of amyloid ß-protein precursor by secretases such as the γ-secretase complex, preferentially located in detergent-resistant membrane (DRM) regions and comprising endoproteolysed amino- and carboxy-terminal fragments of presenilin, nicastrin, anterior pharynx defective 1 and presenilin enhancer 2. Whereas some of familial AD patients harbor causative PSEN mutations that lead to more generation of neurotoxic Aß42, the contribution of Aß generation to sporadic/late-onset AD remains unclear. We found that the carboxy-terminal fragment of presenilin 1 was redistributed from DRM regions to detergent-soluble membrane (non-DRM) regions in brain tissue samples from individuals with sporadic AD. DRM fractions from AD brain sample had the ability to generate significantly more Aß and had a lower cholesterol content than DRM fractions from non-demented control subjects. We further demonstrated that lowering the cholesterol content of DRM regions from cultured cells contributed to the redistribution of γ-secretase components and Aß production. Taken together, the present analyses suggest that the lowered cholesterol content in DRM regions may be a cause of sporadic/late-onset AD by enhancing overall Aß generation.
Subject(s)
Alzheimer Disease/pathology , Amyloid Precursor Protein Secretases/metabolism , Amyloid beta-Peptides/metabolism , Brain/metabolism , Cholesterol/metabolism , Membrane Microdomains/pathology , Aged , Aged, 80 and over , Alzheimer Disease/genetics , Alzheimer Disease/metabolism , Amyloid Precursor Protein Secretases/genetics , Case-Control Studies , Female , Humans , Male , Membrane Microdomains/metabolism , Mutation , Presenilin-1/genetics , Presenilin-2/geneticsABSTRACT
INTRODUCTION: Neuronal p3-Alcß peptides are generated from the precursor protein Alcadein ß (Alcß) through cleavage by α- and γ-secretases of the amyloid ß (Aß) protein precursor (APP). To reveal whether p3-Alcß is involved in Alzheimer's disease (AD) contributes for the development of novel therapy and/or drug targets. METHODS: We developed new sandwich enzyme-linked immunosorbent assay (sELISA) systems to quantitate levels of p3-Alcß in the cerebrospinal fluid (CSF). RESULTS: In monkeys, CSF p3-Alcß decreases with age, and the aging is also accompanied by decreased brain expression of Alcß. In humans, CSF p3-Alcß levels decrease to a greater extent in those with AD than in age-matched controls. Subjects carrying presenilin gene mutations show a significantly lower CSF p3-Alcß level. A cell study with an inverse modulator of γ-secretase remarkably reduces the generation of p3-Alcß37 while increasing the production of Aß42. DISCUSSION: Aging decreases the generation of p3-Alcß, and further significant decrease of p3-Alcß caused by aberrant γ-secretase activity may accelerate pathogenesis in AD.
ABSTRACT
AIM: To evaluate and identify the risk factors for abnormal menstruation after radical trachelectomy. METHODS: This study included 58 patients who underwent radical trachelectomy at our hospital between April 2005 and January 2018. Patients were divided into groups of those with no change in postoperative menstruation (regular [R] group; n = 46) and those with abnormal menstruation such as amenorrhea or hypomenorrhea (irregular [I] group; n = 12). The perioperative characteristics and fertility of the groups were compared retrospectively. The data were statistically analyzed using Student's t-test, Fisher's exact test and Mann-Whitney U test for univariate analysis and logistic regression analysis for multivariate analysis, with the level of statistical significance set at P < 0.05. RESULTS: Based on Federation of Gynecology and Obstetrics staging, 54 patients had stage IB1, 2 had stage IB2 and 2 had stage IIA1 cervical cancer. Eight patients received neoadjuvant chemotherapy. Pretreatment tumor size, residual uterine cavity length and neoadjuvant and postoperative chemotherapy use were not significantly different between the groups. Abnormal menstruation was significantly more common in patients with postoperative pelvic infection (R group, 13.0%; I group, 58.3%) and cervical stenosis (R group, 15.2%; I group, 58.3%). CONCLUSION: To maintain healthy menstruation even after radical trachelectomy, it is important to prevent postoperative pelvic infection and cervical stenosis.
Subject(s)
Menstruation Disturbances/etiology , Menstruation , Postoperative Complications/pathology , Trachelectomy/adverse effects , Uterine Cervical Neoplasms/surgery , Adult , Cervix Uteri/pathology , Constriction, Pathologic , Female , Humans , Menstruation Disturbances/pathology , Neoplasm Staging , Pelvic Infection/etiology , Pelvic Infection/pathology , Pelvis/pathology , Postoperative Complications/etiology , Pregnancy , Retrospective Studies , Trachelectomy/methods , Uterine Cervical Diseases/etiology , Uterine Cervical Diseases/pathology , Uterine Cervical Neoplasms/pathology , Uterine Cervical Neoplasms/physiopathologyABSTRACT
Systemic lupus erythematosus (SLE) may be associated with various types of malignancy. However, SLE occurring with ovarian cancer seems rare, and reliable therapeutic approaches for such cases have yet to be identified. We herein report a case of SLE with ovarian cancer that was successfully treated with corticosteroid, plasmapheresis and chemotherapy. This case may provide new insights into treatment approaches for SLE with ovarian cancer.
Subject(s)
Lupus Erythematosus, Systemic/complications , Ovarian Neoplasms/complications , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Combined Modality Therapy , Female , Glucocorticoids/therapeutic use , Humans , Hysterectomy , Lupus Erythematosus, Systemic/therapy , Magnetic Resonance Imaging , Middle Aged , Ovarian Neoplasms/diagnostic imaging , Ovarian Neoplasms/therapy , Plasmapheresis , Positron Emission Tomography Computed TomographyABSTRACT
X11/Mint 1 and X11-like (X11L)/Mint 2 are neuronal adaptor protein to regulate trafficking and/or localization of various membrane proteins. By analyzing the localization of neuronal membrane proteins in X11-, X11L-, and X11/X11L doubly deficient mice with membrane fractionation procedures, we found that deficient of X11 and X11L decreased the level of glutamate receptors in non-PSD fraction. This finding suggests that X11 and X11L regulate the glutamate receptor micro-localization to the extrasynaptic region. In vitro coimmunoprecipitation studies of NMDA receptors lacking various cytoplasmic regions with X11 and X11L proteins harboring domain deletion suggest that extrasynaptic localization of NMDA receptor may be as a result of the multiple interactions of the receptor subunits with X11 and X11L regulated by protein phosphorylation, while that of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor subunits is not dependent on the binding with X11 and X11L proteins. Because the loss of X11 and X11L tends to impair the exocytosis, but not endocytosis, of glutamate receptors, NMDA receptors are likely to be supplied to the extrasynaptic plasma membrane with a way distinct from the mechanism regulating the localization of NMDA receptors into synaptic membrane region. Reduced localization of NMDA receptor into the extrasynaptic region increased slightly the phosphorylation level of cAMP responsible element binding protein in brain of X11/X11L doubly deficient mice compare to wild-type mice, suggesting a possible role of X11 and X11L in the regulation of signal transduction pathway through extrasynaptic glutamate receptors. OPEN SCIENCE BADGES: This article has received a badge for *Open Materials* because it provided all relevant information to reproduce the study in the manuscript. The complete Open Science Disclosure form for this article can be found at the end of the article. More information about the Open Practices badges can be found at https://cos.io/our-services/open-science-badges/.
Subject(s)
Adaptor Proteins, Signal Transducing/metabolism , Brain/metabolism , Carrier Proteins/metabolism , Nerve Tissue Proteins/metabolism , Protein Transport/physiology , Receptors, N-Methyl-D-Aspartate/metabolism , Animals , Mice , Mice, Inbred C57BL , Mice, Knockout , Neurons/metabolismABSTRACT
Amyloid ß-protein precursor (APP) is transported mainly by kinesin-1 and at a higher velocity than other kinesin-1 cargos, such as Alcadein α (Alcα); this is denoted by the enhanced fast velocity (EFV). Interaction of the APP cytoplasmic region with kinesin-1, which is essential for EFV transport, is mediated by JNK-interacting protein 1 (JIP1). To determine the roles of interactions between the APP luminal region and cargo components, we monitored transport of chimeric cargo receptors, Alcα (luminal)-APP (cytoplasmic) and APP (luminal)-Alcα (cytoplasmic). Alcα-APP is transported at the EFV, whereas APP-Alcα is transported at the same velocity as wild-type Alcα. Thus, the cytoplasmic region of APP is necessary and sufficient for the EFV of APP transport by kinesin-1.
Subject(s)
Amyloid beta-Protein Precursor/chemistry , Amyloid beta-Protein Precursor/metabolism , Cytoplasm/metabolism , Kinesins/metabolism , Neurons/metabolism , Adaptor Proteins, Signal Transducing/metabolism , Animals , Calcium-Binding Proteins , Cell Line , Humans , Mice , Protein Binding , Protein TransportABSTRACT
Generation of amyloid-ß peptides (Aßs) by proteolytic cleavage of the amyloid-ß protein precursor (AßPP), especially increased production of Aß42/Aß43 over Aß40, and their aggregation as oligomers and plaques, represent a characteristic feature of Alzheimer's disease (AD). In familial AD (FAD), altered Aß production originates from specific mutations of AßPP or presenilins 1/2 (PS1/PS2), the catalytic subunits of γ-secretase. In sporadic AD, the origin of altered production of Aßs remains unknown. We hypothesize that the 'human chemical exposome' contains products able to favor the production of Aß42/Aß43 over Aß40 and shorter Aßs. To detect such products, we screened a library of 3500â+âcompounds in a cell-based assay for enhanced Aß42/Aß43 production. Nine pyrazole insecticides were found to induce a ß- and γ-secretase-dependent, 3-10-fold increase in the production of extracellular Aß42 in various cell lines and neurons differentiated from induced pluripotent stem cells derived from healthy and FAD patients. Immunoprecipitation/mass spectrometry analyses showed increased production of Aßs cleaved at positions 42/43, and reduced production of peptides cleaved at positions 38 and shorter. Strongly supporting a direct effect on γ-secretase activity, pyrazoles shifted the cleavage pattern of another γ-secretase substrate, alcadeinα, and shifted the cleavage of AßPP by highly purified γ-secretase toward Aß42/Aß43. Focusing on fipronil, we showed that some of its metabolites, in particular the persistent fipronil sulfone, also favor the production of Aß42/Aß43 in both cell-based and cell-free systems. Fipronil administered orally to mice and rats is known to be metabolized rapidly, mostly to fipronil sulfone, which stably accumulates in adipose tissue and brain. In conclusion, several widely used pyrazole insecticides enhance the production of toxic, aggregation prone Aß42/Aß43 peptides, suggesting the possible existence of environmental "Alzheimerogens" which may contribute to the initiation and propagation of the amyloidogenic process in sporadic AD.
Subject(s)
Amyloid beta-Peptides/metabolism , Insecticides/adverse effects , Peptide Fragments/metabolism , Pyrazoles/adverse effects , Adipose Tissue/drug effects , Adipose Tissue/metabolism , Alzheimer Disease/etiology , Alzheimer Disease/metabolism , Amyloid Precursor Protein Secretases/metabolism , Animals , Brain/drug effects , Brain/metabolism , Environmental Exposure , HEK293 Cells , Humans , Induced Pluripotent Stem Cells/drug effects , Induced Pluripotent Stem Cells/metabolism , Insecticides/chemistry , Insecticides/pharmacokinetics , Mice , Neurons/drug effects , Neurons/metabolism , Proteome/drug effects , Pyrazoles/chemistry , Pyrazoles/pharmacokinetics , RatsABSTRACT
Alcadein α (Alcα) is a major cargo of kinesin-1 that is subjected to anterograde transport in neuronal axons. Two tryptophan- and aspartic acid-containing (WD) motifs located in its cytoplasmic domain directly bind the tetratricopeptide repeat (TPR) motifs of the kinesin light chain (KLC), which activate kinesin-1 and recruit kinesin-1 to Alcα cargo. We found that phosphorylation of three serine residues in the acidic region located between the two WD motifs is required for interaction with KLC. Phosphorylation of these serine residues may alter the disordered structure of the acidic region to induce direct association with KLC. Replacement of these serines with Ala results in a mutant that is unable to bind kinesin-1, which impairs exit of Alcα cargo from the Golgi. Despite this deficiency, the compromised Alcα mutant was still transported, albeit improperly by vesicles following missorting of the Alcα mutant with amyloid ß-protein precursor (APP) cargo. This suggests that APP partially compensates for defective Alcα in anterograde transport by providing an alternative cargo receptor for kinesin-1.
Subject(s)
Calcium-Binding Proteins/metabolism , Golgi Apparatus/metabolism , Kinesins/metabolism , Adaptor Proteins, Signal Transducing/metabolism , Amyloid beta-Peptides/metabolism , Amyloid beta-Protein Precursor/metabolism , Animals , Axonal Transport , Biological Transport , Calcium-Binding Proteins/genetics , HEK293 Cells , Humans , Mice , Mice, Inbred C57BL , Microtubule-Associated Proteins/metabolism , Phosphorylation , Protein DomainsABSTRACT
In neurons, amyloid ß-protein precursor (APP) is transported by binding to kinesin-1, mediated by JNK-interacting protein 1b (JIP1b), which generates the enhanced fast velocity (EFV) and efficient high frequency (EHF) of APP anterograde transport. Previously, we showed that EFV requires conventional interaction between the JIP1b C-terminal region and the kinesin light chain 1 (KLC1) tetratricopeptide repeat, whereas EHF requires a novel interaction between the central region of JIP1b and the coiled-coil domain of KLC1. We found that phosphorylatable Thr466 of KLC1 regulates the conventional interaction with JIP1b. Substitution of Glu for Thr466 abolished this interaction and EFV, but did not impair the novel interaction responsible for EHF. Phosphorylation of KLC1 at Thr466 increased in aged brains, and JIP1 binding to kinesin-1 decreased, suggesting that APP transport is impaired by aging. We conclude that phosphorylation of KLC1 at Thr466 regulates the velocity of transport of APP by kinesin-1 by modulating its interaction with JIP1b.
Subject(s)
Adaptor Proteins, Signal Transducing/metabolism , Amyloid beta-Protein Precursor/metabolism , Kinesins/metabolism , Microtubule-Associated Proteins/metabolism , Adaptor Proteins, Signal Transducing/genetics , Amyloid beta-Peptides/metabolism , Amyloid beta-Protein Precursor/genetics , Animals , COS Cells , Chlorocebus aethiops , Cytoplasm/metabolism , Mice , Neurons/metabolism , Phosphorylation , Protein Binding , Protein Domains , Protein Structural Elements , Protein TransportABSTRACT
INTRODUCTION: Vaginal cuff dehiscence after hysterectomy is a rare complication and occurs in less than 1% of patients. It can present with serious complications, such as bowel evisceration and peritonitis. PRESENTATION OF CASE: A 51-year-old multigravida Korean woman underwent total laparoscopic hysterectomy for leiomyoma. Six months later, she reported lower abdominal pain and vaginal bleeding. Physical examination revealed rebound tenderness in the lower abdomen, and pelvic examination showed a small amount of vaginal bleeding with an evisceration of the small intestine through the vagina that exhibited healthy peristalsis. The eviscerated bowel, which seemed to be a part of the ileum, was carefully manually reduced transvaginally into the abdominal cavity. Laparoscopic observation revealed adhesions between the omentum, small intestine, and the peritoneum. Specifically, the small intestine was adhered around the vaginal cuff. An abdominal abscess was found in the left lower abdominal cavity. An adhesiotomy was performed and the abdominal abscess was removed and irrigated. Complete separation of the anterior and posterior vaginal cuff edges was obtained. The vaginal cuff was closed with interrupted 0-polydioxanone absorbable sutures without bowel injury. A 6-month follow-up examination revealed complete healing of the vaginal cuff. DISCUSSION: In this case, we were able to make use of both laparoscopic and transvaginal methods to perform a successful repair with a minimally invasive and safe technique. CONCLUSION: Laparoscopically assisted vaginal cuff suturing for vaginal cuff dehiscence after total laparoscopic hysterectomy was found to be effective, safe, and minimally invasive.
ABSTRACT
The activities of mitochondrial enzymes, which are essential for neural function, decline with age and in age-related disease. In particular, the activity of cytochrome c oxidase (COX/complex IV) decreases in patients with Alzheimer's disease (AD). COX, a mitochondrial inner membrane protein complex that contains heme, plays an essential role in the electron transport chain that generates ATP. Heme synthesis begins with 5-aminolevulinic acid (5-ALA) in mitochondria. 5-ALA synthetase is the rate-limiting enzyme in heme synthesis, suggesting that supplementation with 5-ALA might help preserve mitochondrial activity in the aged brain. We administered a diet containing 5-ALA to triple-transgenic AD (3xTg-AD) model mice for 6 months, starting at 3 months of age. COX activity and protein expression, as well as mitochondrial membrane potential, were significantly higher in brains of 5-ALA-fed mice than in controls. Synaptotagmin protein levels were also significantly higher in 5-ALA-fed mice, suggesting improved preservation of synapses. Although brain Aß levels tended to decrease in 5-ALA-fed mice, we observed no other significant changes in other biochemical and pathological hallmarks of AD. Nevertheless, our study suggests that daily oral administration of 5-ALA could preserve mitochondrial enzyme activities in the brains of aged individuals, thereby contributing to the preservation of neural activity.