Papers by Nibaldo Inestrosa
Biochemical Journal, Oct 1, 1983
The effect of heparin, a sulphated glycosaminoglycan, on the solubilization of rat sciatic-nerve ... more The effect of heparin, a sulphated glycosaminoglycan, on the solubilization of rat sciatic-nerve acetylcholinesterase (acetylcholine acetylhydrolase; AChE; EC 3.1.1.7) was studied. It was found that heparin solubilized esterase activity from ligated nerves. Sedimentation analysis revealed this activity to be mainly the 16S form. Chondroitin sulphate did not solubilize AChE activity, and protamine eliminated the solubilizing effect. Our results suggest the involvement of sulphated glycosaminoglycans in the intra-axonal localization and transport of 16 S AChE.
Biochemical Journal, Dec 15, 1988
Proteinase K treatment of the bovine brain acetylcholinesterase (AChE) releases a hydrophobic fra... more Proteinase K treatment of the bovine brain acetylcholinesterase (AChE) releases a hydrophobic fragment of 13 kDa, which is entirely responsible for the aggregation of the G4 AChE in the absence of detergent. This observation provides evidence that the 13 kDa fragment, which comes from a previously identified 20 kDa subunit, is directly involved in the attachment of the G4 AChE to brain membranes. A model for the organization of the different sub-domains of the hydrophobic anchor of the G4 AChE is presented.
The sub-Antarctic Magellan Ecoregion is a unique biogeographic area located in the southern end o... more The sub-Antarctic Magellan Ecoregion is a unique biogeographic area located in the southern end of South America with notable marine flora and high endemism. Brown macroalgae, particularly Macrocystis pyrifera, dominate the coastlines and are considered critical ecosystem engineers, providing shelter, food, and reproduction sites for various species. Additionally, they are essential components used in the food industry and biomedicine due to their lipids, amino acids, and fiber content. In this study, we determined the fatty acid content in different thallus structures (holdfast, stipes and fronds) of Macrocystis pyrifera collected in Rinconada Bulnes (53°35ʼ47.76” S; 70°56ʼ08.52” W) in the spring of 2021. The stipes had a highest total lipid content (3.73%) than the fronds (2.74%). The fatty acid profile showed higher values of monounsaturated fatty acids in the stipe (Ʃ 43.0%) and holdfast (Ʃ 41.7%), while fronds displayed higher values of polyunsaturated fatty acids (Ʃ 32.4%). Th...
Journal of Biological Chemistry, Dec 21, 2007
Progress in Neurobiology, 2008
Neurodegenerative Diseases, 2008
Background: Alzheimer’s disease (AD) is the most prevalent neurodegenerative disease in the growi... more Background: Alzheimer’s disease (AD) is the most prevalent neurodegenerative disease in the growing population of elderly people. Synaptic dysfunction is an early manifestation of AD. The cellular mechanism by which β-amyloid peptide (Aβ) affects synapses remains unclear. Aβ oligomers target synapses in cultured rat hippocampal neurons suggesting that they play a key role in the regulation of synapses. Objective: The aim of this work is to study the effect of Aβ oligomers on the central synapses and the possible role of the Wnt signaling pathway in preventing the Aβ effects. Methods: We used rat hippocampal neurons, immunofluorescence and western blot procedures to detect synaptic proteins. Results: Aβ oligomers induced a reduction of the postsynaptic density protein 95 (PSD-95) and the NMDA glutamate receptors. We found that Wnt-5a, a noncanonical Wnt ligand, prevents the decrease triggered by Aβ oligomers in the glutamate receptor and PSD-95. Conclusion: Altogether, our results su...
Journal of Experimental Zoology, 1992
Incorporation of radioactive sulfate to hatched veliger larvae of the gastropod muricid Concholep... more Incorporation of radioactive sulfate to hatched veliger larvae of the gastropod muricid Concholepas concholepas indicated that over 87% of the sulfated macromolecules were found in the detergent insoluble fraction, rich in extracellular matrix (ECM) components. The sulfated material was solubilized with guanidine salt followed by urea dialysis and fractionated by DEAE‐Sephacel chromatography. Three sulfated compounds eluting at 0.7, 1.1, and 3.0 M NaCl, called peaks I, II, and III, respectively, were obtained. The sulfated compound present in peak I was degraded by pronase or sodium alkaline treatment to a small sulfated resistant material, suggesting the presence of a proteoglycan (PG). Filtration analysis on Sephacryl S‐500 and SDS‐PAGE of the intact PG indicates that it has a high molecular weight (360,000 to over 1 × 106). Monoclonal antibodies (mAb) against this PG were produced. The specificity of one mAb, the 6H2, was demonstrated by size chromatography and ELISA analysis. Th...
Biometals, 2003
Increasing evidence supports an important role for metals in neurobiology. In fact, copper bindin... more Increasing evidence supports an important role for metals in neurobiology. In fact, copper binding proteins that form bioinorganic complexes are able to display oxidant or anti-oxidant properties, which would impact on neuronal function or in the triggering of neurodegenerative process. Two proteins related to neurodegenerative diseases have been described as copper binding proteins: the amyloid precursor protein (APP), a protein
Trends in Pharmacological Sciences, 1989
Molecular forms of acetylcholinesterase exhibit tissue-specific distribution, and each form is an... more Molecular forms of acetylcholinesterase exhibit tissue-specific distribution, and each form is anchored to the cell surface via a particular post-translational modification of the catalytic subunit. Nibaldo Inestrosa and Alejandra Perelman review evidence that heparan sulphate proteoglycans are the extracellular matrix receptors for the collagen-tailed enzyme, and that a glycolipid which contains phosphatidylinositol and a 20 kDa hydrophobic peptide participate in the anchoring of the hydrophobic globular forms of acetylcholinesterase to the cell surface.
Neuroscience Letters, 1994
We have studied the development of mouse brain acetylcholinesterase (AChE). Only tetrameric (G4) ... more We have studied the development of mouse brain acetylcholinesterase (AChE). Only tetrameric (G4) and monomeric (G1) forms were detected both in vivo and in vitro. The amphiphilic G4 form increased continuously during development, whereas an amphiphilic G1 form appears transiently around embryonic day 17. A causal relationship between the monomers and tetramers was established using pulse-chase experiments with paraoxon, a reversible AChE inhibitor. We report here, for the first time, the presence of an amphiphilic monomer possibly involved in the assembly of the amphiphilic G4 AChE form during mouse brain development.
Neuroscience Letters, 1977
In order to study the turnover rate of motor endplate acetylcholinesterase (AChE), we have treate... more In order to study the turnover rate of motor endplate acetylcholinesterase (AChE), we have treated hypoglassal nerve with 10 mM colchine, a drug that produced a reversible decrease of AChE from geniohyoid muscle endplates. The return of AChE to the normal steady-state level has been used to calculate an AChE half-life of 4.6 days. This value is very close to that obtained for the half-life of junctional acetylcholine receptors (AChR). Our result supports the contention that both macromolecules have the same turnover rate.
Neurobiology of Disease, 2003
Acetylcholinesterase (AChE) activities in CNS physiopathology are increasingly diverse and range ... more Acetylcholinesterase (AChE) activities in CNS physiopathology are increasingly diverse and range from neuritogenesis, through synaptogenesis, to enhancement of amyloid fiber assembly. In Alzheimer's disease, senile plaques and neurodegeneration specially affect regions enriched for cholinergic synapses. In this study we show an effect of AChE that could contribute to the increased deposition of A in certain regions. Affinity-purified AChE induced the expression of amyloid--precursor protein (-APP) in glial cells in a concentrationdependent manner up to 5 nM. In glia, AChE also increased inducible nitric oxide synthase (iNOS) assessed by immunocytochemistry and decreased reductive metabolism as evidence of cell activation. AChE could increase the expression of -APP in astrocytes and microglia as result of the activation of glial cells. As a whole, we found that AChE has additional effects that could result in an increased synthesis of A, both by increasing -APP expression of astrocytes and by further activating glial cells.
Muscle & Nerve, 1983
The chronic administration of nafenopin, a hypolipidemic drug, induced an increase in catalase an... more The chronic administration of nafenopin, a hypolipidemic drug, induced an increase in catalase and acyl‐CoA oxidase activities in various skeletal muscles, including the gracilis, diaphragm, soles, and extensor digitorum longus. The magnitude of the increase was around 100% for both enzymes in each of the muscles studied in spite of the different basal level. These changes seem to be specific of the peroxisomal enzymes because acetylcholinesterase, which is not peroxisomal, did not follow the same pattern in all the muscles. Concomitant with the increase in muscle peroxisomal enzymes, the skeletal muscles presented an altered electromyogram with prolonged insertional activity, repetitive firing of action potentials, and myotonic runs characteristic of myotonia. Our results suggest a role for peroxisomes in the myotonic disorder.
Molecular Neurobiology, 2013
The signaling pathways activated by Wnt ligands are related to a wide range of critical cell func... more The signaling pathways activated by Wnt ligands are related to a wide range of critical cell functions, such as cell division, migration, and synaptogenesis. Here, we summarize compelling evidence on the role of Wnt signaling on several features of skeletal muscle physiology. We briefly review the role of Wnt pathways on the formation of muscle fibers during prenatal and postnatal myogenesis, highlighting its role on the activation of stem cells of the adult muscles. We also discuss how Wnt signaling regulates the precise formation of neuromuscular synapses, by modulating the differentiation of presynaptic and postsynaptic components, particularly regarding the clustering of acetylcholine receptors on the muscle membrane. In addition, based on previous evidence showing that Wnt pathways are linked to several diseases, such as Alzheimer's and cancer, we address recent studies indicating that Wnt signaling plays a key role in skeletal muscle fibrosis, a disease characterized by an increase in the extracellular matrix components leading to failure in muscle regeneration, tissue disorganization and loss of muscle activity. In this context, we also discuss the possible cross-talk between the Wnt/β-catenin pathway with two other critical profibrotic pathways, transforming growth factor β and connective tissue growth factor, which are potent stimulators of the accumulation of connective tissue, an effect characteristic of the fibrotic condition. As it has emerged in other pathological conditions, we suggests that muscle fibrosis may be a consequence of alterations of Wnt signaling activity.
Molecular Aspects of Medicine, 2005
Copper is an essential metal in living organisms; thus, the maintenance of adequate copper levels... more Copper is an essential metal in living organisms; thus, the maintenance of adequate copper levels is of vital importance and is highly regulated. Dysfunction of copper metabolism leading to its excess or deficiency results in severe ailments. Two examples of illnesses related to alterations in copper metabolism are Menkes and Wilson diseases. Several proteins are involved in the maintenance of copper homeostasis, including copper transporters and metal chaperones. In the last several years, the b-amyloid-precursor protein (b-APP) and the prion protein (PrP C ), which are related to the neurodegenerative disorders Alzheimer and prion diseases respectively, have been associated with copper metabolism. Both proteins bind copper through copper-binding domains that also have been shown to reduce copper in vitro. Moreover, this ability to reduce copper is associated with a neuroprotective effect exerted by the copper-binding domain of both proteins against copper in vivo. In addition to a functional link between copper and b-APP or PrP C , evidence suggests that copper has a role in Alzheimer and prion diseases. Here, we review the evidence that supports both, the role of b-APP and PrP C , in copper metabolism and the putative role of copper in neurodegenerative diseases.
Journal of Neurochemistry, 1985
We studied the distribution of the molecular forms of acetylcholinesterase (AChE) in a stable var... more We studied the distribution of the molecular forms of acetylcholinesterase (AChE) in a stable variant (F3) of the rat pheochromocytoma cell line, PC12, that lacks a heparan sulfate proteoglycan on the cell surface. After treatment with nerve growth factor F3 cells synthesize less 4S enzyme, and more 10S and 16S enzyme than normal PC12 cells. This distribution is similar to that seen in normal cells after incubation with beta-D-xylosides, molecules that interfere with proteoglycan assembly. Using collagenase treatment and membrane-permeable and -impermeable inhibitors of AChE, we determined the cellular location of the AChE forms. Although in normal cells greater than 90% of the 16S AChE is on the cell surface, approximately 60% is present in an internal pool in the variant. Following irreversible inhibition of all forms of AChE in the variant, the newly synthesized 16S AChE appears in the internal pool after a 1-h lag, but is not detected on the cell surface until after 2.5 h. Our results thus show that 16S AChE is assembled internally within neuronal cells and that alterations in the synthesis and distribution of proteoglycans affect the total amount and cellular localization of the 16S AChE form.
Journal of Experimental Marine Biology and Ecology, 1993
Metamorphosis may be the most critical point in the life history of marine moltuses. Excess potas... more Metamorphosis may be the most critical point in the life history of marine moltuses. Excess potassium was used to trigger the metamorphic process in competent larvae of the prosobran~h Co~ch~~e~as c~nc~u~epa~ Bruguiere. The specific, irreversible stimulation of complex mo~hogenetic events by this exogenous factor was used to study some molecular changes that occur during metamo~hosis. Results show that mat~o~hosis entails several molecular changes, including: (1) a modification in the pattern of protein synthesis measured by incorporation of r3~SImethioni~e to newly synthetized polypeptides, (2) an increase of [%i]methionine incorporation in hep~n-binding proteins or the induction of hep~in-binding proteins (i.e. growth factors?), (3) a decrease (20 times) in the larval Ievels of the second messenger cyclic AMP, and (4) the appearance of a new form of the neurotransmitter-related enzyme, acetylchalin~sterase (AChE). To our knowledge this is the first attempt to characterize some of the molecular changes that take place during molluscan metamorphosis.
Journal of Cellular Physiology, 1996
We have studied the influence of the extracellular matrix (ECM) on the amount of β-amyloid precur... more We have studied the influence of the extracellular matrix (ECM) on the amount of β-amyloid precursor protein (APP) and C-terminal amyloid-bearing fragments in 3T3 fibroblasts. After incubation with ECM components, the cellular APP content of 3T3 cells changed. Besides, different ...
Developmental Biology, 1984
We have examined the expression, the location, and the physiological activity of acetylcholineste... more We have examined the expression, the location, and the physiological activity of acetylcholinesterase (AChE) in developing intercostal muscles in the rat. Although focal accumulations of AChE at developing end plates do not appear until Embryonic Day (ED) 16-17, 16 S AChE is present at ED 14. Experiments with permeable and impermeable inhibitors established that prior to focal accumulation most of the 16 S enzyme is on the surface of muscle fibers, where it constitutes the major species. Intracellular recording from developing muscle fibers showed that as early as ED 14, AChE inhibitors prolonged evoked end-plate potentials. We conclude that prior to its focal accumulation, AChE is present on the surface of muscle fibers and is physiologically active. Histochemical staining of the focally accumulated enzyme demonstrated that the enzyme is concentrated both intracellularly and extracellularly at the sites of developing nerve-muscle contacts.
Current Alzheimer Research, 2004
Alzheimer's disease (AD) is characterized by selective neuronal cell death, which is probably... more Alzheimer's disease (AD) is characterized by selective neuronal cell death, which is probably caused by amyloid beta-peptide (Abeta) oligomers and fibrils. We have found that acetylcholinesterase (AChE), a senile plaque component, increases amyloid fibril assembly with the formation of highly toxic complexes (Abeta-AChE). The neurotoxic effect induced by Abeta-AChE complexes was higher than that induced by the Abeta peptide alone as shown both in vitro (hippocampal neurons) and in vivo (rats injected with Abeta peptide in the dorsal hippocampus). Interestingly, treatment with Abeta-AChE complexes decreases the cytoplasmic beta-catenin level, a key component of Wnt signaling. Conversely, the activation of this signaling pathway by Wnt-3a promotes neuronal survival and rescues changes in Wnt components (activation or subcellular localization). Moreover Frzb-1, a Wnt antagonist reverses the Wnt-3a neuroprotection effect against Abeta neurotoxicity. Compounds that mimic the Wnt signaling or modulate the cross-talking with this pathway could be used as neuroprotective agents for therapeutic strategies in AD patients.
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Papers by Nibaldo Inestrosa