Inhibition of cathepsin B reduces β-amyloid production in regulated secretory vesicles of neuronal chromaffin cells: evidence for cathepsin B as a candidate β-secretase of Alzheimer's disease

2005 ◽  
Vol 386 (12) ◽  
pp. 1325-1325 ◽  
Author(s):  
Vivian Hook ◽  
Thomas Toneff ◽  
Matthew Bogyo ◽  
Doron Greenbaum ◽  
Katalin F. Medzihradszky ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cathepsin B ◽  
Chromaffin Cells ◽  
Secretory Vesicles ◽  
Β Amyloid

Inhibition of cathepsin B reduces β-amyloid production in regulated secretory vesicles of neuronal chromaffin cells: evidence for cathepsin B as a candidate β-secretase of Alzheimer's disease

2005 ◽  
Vol 386 (9) ◽  
Author(s):  
Vivian Hook ◽  
Thomas Toneff ◽  
Matthew Bogyo ◽  
Doron Greenbaum ◽  
Katalin F. Medzihradszky ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cysteine Protease ◽  
Cathepsin B ◽  
Protease Activity ◽  
Chromaffin Cells ◽  
Secretory Pathway ◽  
Secretory Vesicles ◽  
Cysteine Protease Activity ◽  
Regulated Secretory Pathway

AbstractThe regulated secretory pathway of neurons is the major source of extracellular Aβ that accumulates in Alzheimer's disease (AD). Extracellular Aβ secreted from that pathway is generated by β-secretase processing of amyloid precursor protein (APP). Previously, cysteine protease activity was demonstrated as the major β-secretase activity in regulated secretory vesicles of neuronal chromaffin cells. In this study, the representative cysteine protease activity in these secretory vesicles was purified and identified as cathepsin B by peptide sequencing. Immunoelectron microscopy demonstrated colocalization of cathepsin B with Aβ in these vesicles. The selective cathepsin B inhibitor, CA074, blocked the conversion of endogenous APP to Aβ in isolated regulated secretory vesicles. In chromaffin cells, CA074Me (a cell permeable form of CA074) reduced by about 50% the extracellular Aβ released by the regulated secretory pathway, but CA074Me had no effect on Aβ released by the constitutive pathway. Furthermore, CA074Me inhibited processing of APP into the COOH-terminal β-secretase-like cleavage product. These results provide evidence for cathepsin B as a candidate β-secretase in regulated secretory vesicles of neuronal chromaffin cells. These findings implicate cathepsin B as β-secretase in the regulated secretory pathway of brain neurons, suggesting that inhibitors of cathepsin B may be considered as therapeutic agents to reduce Aβ in AD.

scholarly journals Pharmacogenetic features of cathepsin B inhibitors that improve memory deficit and reduce β-amyloid related to Alzheimer's disease

2010 ◽  
Vol 391 (8) ◽  
Author(s):  
Vivian Hook ◽  
Gregory Hook ◽  
Mark Kindy
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Mouse Models ◽  
Cathepsin B ◽  
Memory Deficit ◽  
Mutant Site ◽  
Amyloid Aβ ◽  
Β Amyloid ◽  
The Brain ◽  
Aβ Production

Abstract Beta-amyloid (Aβ) in the brain is a major factor involved in Alzheimer's disease (AD) that results in severe memory deficit. Our recent studies demonstrate pharmacogenetic differences in the effects of inhibitors of cathepsin B to improve memory and reduce Aβ in different mouse models of AD. The inhibitors improve memory and reduce brain Aβ in mice expressing the wild-type (WT) β-secretase site of human APP, expressed in most AD patients. However, these inhibitors have no effect in mice expressing the rare Swedish (Swe) mutant amyloid precursor protein (APP). Knockout of the cathepsin B decreased brain Aβ in mice expressing WT APP, validating cathepsin B as the target. The specificity of cathepsin B to cleave the WT β-secretase site, but not the Swe mutant site, of APP for Aβ production explains the distinct inhibitor responses in the different AD mouse models. In contrast to cathepsin B, the BACE1 β-secretase prefers to cleave the Swe mutant site. Discussion of BACE1 data in the field indicate that they do not preclude cathepsin B as also being a β-secretase. Cathepsin B and BACE1 could participate jointly as β-secretases. Significantly, the majority of AD patients express WT APP and, therefore, inhibitors of cathepsin B represent candidate drugs for AD.

scholarly journals Alternative pathways for production of β-amyloid peptides of Alzheimer's disease

2008 ◽  
Vol 389 (8) ◽  
Author(s):  
Vivian Hook ◽  
Israel Schechter ◽  
Hans-Ulrich Demuth ◽  
Gregory Hook
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Posttranslational Modifications ◽  
Cathepsin B ◽  
Cathepsin D ◽  
General Meeting ◽  
Glutaminyl Cyclase ◽  
Alternative Pathways ◽  
Β Amyloid ◽  
Bace 1

Abstract This highlight article describes three Alzheimer's disease (AD) studies presented at the 5th General Meeting of the International Proteolysis Society that address enzymatic mechanisms for producing neurotoxic β-amyloid (Aβ) peptides. One group described the poor kinetics of BACE 1 for cleaving the wild-type (WT) β-secretase site of APP found in most AD patients. They showed that cathepsin D displays BACE 1-like specificity and cathepsin D is 280-fold more abundant in human brain than BACE 1. Nevertheless, as BACE 1 and cathepsin D show poor activity towards the WT β-secretase site, they suggested continuing the search for additional β-secretase(s). The second group reported cathepsin B as an alternative β-secretase possessing excellent kinetic efficiency and specificity for the WT β-secretase site. Significantly, inhibitors of cathepsin B improved memory, with reduced amyloid plaques and decreased Aβ(40/42) in brains of AD animal models expressing amyloid precursor protein containing the WT β-secretase site. The third group addressed isoaspartate and pyroglutamate (pGlu) posttranslational modifications of Aβ. Results showed that cathepsin B, but not BACE 1, efficiently cleaves the WT β-secretase isoaspartate site. Furthermore, cyclization of N-terminal Glu by glutaminyl cyclase generates highly amyloidogenic pGluAβ(3–40/42). These presentations suggest cathepsin B and glutaminyl cyclase as potential new AD therapeutic targets.

Аnticholinesterase and antioxidant activity of new binary conjugates of (с)-carbolines

2019 ◽  
Vol 484 (1) ◽  
pp. 104-108
Author(s):  
G. F. Makhaeva ◽  
E. F. Shevtsova ◽  
N. P. Boltneva ◽  
N. V. Kovaleva ◽  
E. V. Rudakova ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Antioxidant Activity ◽  
Anticholinesterase Activity ◽  
Amyloid Aggregation ◽  
Varying Length ◽  
Β Amyloid ◽  
New Compounds

This study presents the synthesis of binary tetrohydro-γ-carbolines with ditriazol spacers of varying length, which exhibit anticholinesterase and antioxidant activity, as compared to the original Dimebon prototype. Anticholinesterase activity suggests the potential ability of the new compounds to block β-amyloid aggregation induced by anticholinesterase, making them promising candidates for further research preparations for the treatment of Alzheimer's disease. Particular attention should be paid to the conjugate with an intertriazol hexamethylene spacer, which can be regarded as the leading compound in this series.

Alzheimer’s Disease: Erythrocyte 2,3-diphosphoglycerate Content and Circulating Erythropoietin

2019 ◽  
Vol 16 (9) ◽  
pp. 834-835
Author(s):  
Petter Järemo ◽  
Alenka Jejcic ◽  
Vesna Jelic ◽  
Tasmin Shahnaz ◽  
Homira Behbahani ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cognitive Impairment ◽  
Cell Damage ◽  
Control Group ◽  
Red Cell ◽  
Oxygen Release ◽  
Regulatory Pathways ◽  
Β Amyloid ◽  
2,3 Dpg

Background: Alzheimer’s Disease (AD) features the accumulation of β-amyloid in erythrocytes. The subsequent red cell damage may well affect their oxygen-carrying capabilities. 2,3- diphosphoglycerate (2,3-DPG) binds to the hemoglobin thereby promoting oxygen release. It is theorized that 2,3-DPG is reduced in AD and that the resulting hypoxia triggers erythropoietin (EPO) release. Methods & Objective: To explore this theory, we analyzed red cell 2,3-DPG content and EPO in AD, mild cognitive impairment, and the control group, subjective cognitive impairment. Results: We studied (i) 2,3-DPG in red cells, and (ii) circulating EPO in AD, and both markers were unaffected by dementia. Disturbances of these oxygen-regulatory pathways do not appear to participate in brain hypoxia in AD.

Synthesis of a Novel Curcumin Derivative as a Potential Imaging Probe in Alzheimer’s Disease Imaging

2019 ◽  
Vol 16 (8) ◽  
pp. 723-731 ◽  
Author(s):  
Alexander Sturzu ◽  
Sumbla Sheikh ◽  
Hubert Kalbacher ◽  
Thomas Nägele ◽  
Christopher Weidenmaier ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Flow Cytometry ◽  
Transgenic Mice ◽  
Ex Vivo ◽  
Amyloid Plaques ◽  
Laser Scanning Microscopy ◽  
Β Amyloid ◽  
Curcumin Derivative

Background: Curcumin has been of interest in the field of Alzheimer’s disease. Early studies on transgenic mice showed promising results in the reduction of amyloid plaques.However, curcumin is very poorly soluble in aqueous solutions and not easily accessible to coupling as it contains only phenolic groups as potential coupling sites. For these reasons only few imaging studies using curcumin bound as an ester were performed and curcumin is mainly used as nutritional supplement. Methods: In the present study we produced an aminoethyl ether derivative of curcumin using a nucleophilic substitution reaction. This is a small modification and should not impact the properties of curcumin while introducing an easily accessible reactive amino group. This novel compound could be used to couple curcumin to other molecules using the standard methods of peptide synthesis. We studied the aminoethyl-curcumin compound and a tripeptide carrying this aminoethyl-curcumin and the fluorescent dye fluorescein (FITC-curcumin) in vitro on cell culture using confocal laser scanning microscopy and flow cytometry. Then these two substances were tested ex vivo on brain sections prepared from transgenic mice depicting Alzheimer-like β-amyloid plaques. Results: In the in vitro CLSM microscopy and flow cytometry experiments we found dot-like unspecific uptake and only slight cytotoxicity correlating with this uptake. As these measurements were optimized for the use of fluorescein as dye we found that the curcumin at 488nm fluorescence excitation was not strong enough to use it as a fluorescence marker in these applications. In the ex vivo sections CLSM experiments both the aminoethyl-curcumin and the FITC-curcumin peptide bound specifically to β- amyloid plaques. Conclusion: In conclusion we successfully produced a novel curcumin derivative which could easily be coupled to other imaging or therapeutic molecules as a sensor for amyloid plaques.

MiR-335-5p Inhibits β-Amyloid (Aβ) Accumulation to Attenuate Cognitive Deficits Through Targeting c-jun-N-terminal Kinase 3 in Alzheimer’s Disease

2020 ◽  
Vol 17 (1) ◽  
pp. 93-101 ◽  
Author(s):  
Dan Wang ◽  
Zhifu Fei ◽  
Song Luo ◽  
Hai Wang
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Transgenic Mice ◽  
Western Blot ◽  
Mrna Expression ◽  
Cognitive Deficits ◽  
Protein Levels ◽  
Amyloid Aβ ◽  
Β Amyloid ◽  
The Relationship

Objectives: Alzheimer's disease (AD), also known as senile dementia, is a common neurodegenerative disease characterized by progressive cognitive impairment and personality changes. Numerous evidences have suggested that microRNAs (miRNAs) are involved in the pathogenesis and development of AD. However, the exact role of miR-335-5p in the progression of AD is still not clearly clarified. Methods: The protein and mRNA levels were measured by western blot and RNA extraction and quantitative real-time PCR (qRT-PCR), respectively. The relationship between miR-335-5p and c-jun-N-terminal kinase 3 (JNK3) was confirmed by dual-luciferase reporter assay. SH-SY5Y cells were transfected with APP mutant gene to establish the in vitro AD cell model. Flow cytometry and western blot were performed to evaluate cell apoptosis. The APP/PS1 transgenic mice were used as an in vivo AD model. Morris water maze test was performed to assess the effect of miR- 335-5p on the cognitive deficits in APP/PS1 transgenic mice. Results: The JNK3 mRNA expression and protein levels of JNK3 and β-Amyloid (Aβ) were significantly up-regulated, and the mRNA expression of miR-335-5p was down-regulated in the brain tissues of AD patients. The expression levels of miR-335-5p and JNK3 were significantly inversely correlated. Further, the dual Luciferase assay verified the relationship between miR-335- 5p and JNK3. Overexpression of miR-335-5p significantly decreased the protein levels of JNK3 and Aβ and inhibited apoptosis in SH-SY5Y/APPswe cells, whereas the inhibition of miR-335-5p obtained the opposite results. Moreover, the overexpression of miR-335-5p remarkably improved the cognitive abilities of APP/PS1 mice. Conclusion: The results revealed that the increased JNK3 expression, negatively regulated by miR-335-5p, may be a potential mechanism that contributes to Aβ accumulation and AD progression, indicating a novel approach for AD treatment.

Biological Signatures of Alzheimer’s Disease

2020 ◽  
Vol 20 (9) ◽  
pp. 770-781 ◽  
Author(s):  
Poornima Sharma ◽  
Anjali Sharma ◽  
Faizana Fayaz ◽  
Sharad Wakode ◽  
Faheem H. Pottoo
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
White Matter ◽  
Senile Plaque ◽  
Senile Plaques ◽  
Amyloid Deposition ◽  
Immune Defense ◽  
Amyloid Angiopathy ◽  
Microvascular Changes ◽  
Β Amyloid

Alzheimer’s disease (AD) is the most prevalent and severe neurodegenerative disease affecting more than 0.024 billion people globally, more common in women as compared to men. Senile plaques and amyloid deposition are among the main causes of AD. Amyloid deposition is considered as a central event which induces the link between the production of β amyloid and vascular changes. Presence of numerous biomarkers such as cerebral amyloid angiopathy, microvascular changes, senile plaques, changes in white matter, granulovascular degeneration specifies the manifestation of AD while an aggregation of tau protein is considered as a primary marker of AD. Likewise, microvascular changes, activation of microglia (immune defense system of CNS), amyloid-beta aggregation, senile plaque and many more biomarkers are nearly found in all Alzheimer’s patients. It was seen that 70% of Alzheimer’s cases occur due to genetic factors. It has been reported in various studies that apolipoprotein E(APOE) mainly APOE4 is one of the major risk factors for the later onset of AD. Several pathological changes also occur in the white matter which include dilation of the perivascular space, loss of axons, reactive astrocytosis, oligodendrocytes and failure to drain interstitial fluid. In this review, we aim to highlight the various biological signatures associated with the AD which may further help in discovering multitargeting drug therapy.

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