Neuronal cells derived from human induced pluripotent stem cells as a functional tool of melanocortin system.

Background: The preparation of human neurons derived from human induced pluripotent stem (iPS) cells can serve as a potential tool for evaluating the physiological and pathophysiological properties of human neurons and for drug development.

Methods: In the present study, the functional activity in neuronal cells differentiated from human iPS cells was observed.

Results: The differentiated cells expressed mRNAs for classical neuronal markers (microtubule-associated protein 2, β-tubulin III, calbindin 1, synaptophysin and postsynaptic density protein 95) and for subunits of various excitatory and inhibitory transmitters (NR1, NR2A, NR2B, GABA α1).

Hippocampal administration of chondroitinase ABC increases plaque-adjacent synaptic marker and diminishes amyloid burden in aged APPswe/PS1dE9 mice.

Introduction: Substantial data has shown that the lectican group of chondroitin sulfate proteoglycans are involved in inhibition of axonal plasticity in response to injury in the central nervous system. Increasing evidence indicates that lecticans may also play a role in synaptic plasticity related to memory, especially associated with aging. A recent study has shown that lectican expression is elevated at a young age in the APPswe/PS1dE9 mouse model and Alzheimer's disease (AD) and hippocampal treatment with chondroitinase ABC reversed a loss of contextual fear memory and restored long-term potentiation.

ADAMTS expression and function in central nervous system injury and disorders.

The components of the adult extracellular matrix in the central nervous system form a lattice-like structure that is deposited as perineuronal nets, around axon initial segments and as synapse-associated matrix. An abundant component of this matrix is the lecticans, chondroitin sulfate-bearing proteoglycans that are the major substrate for several members of the ADAMTSs (a disintegrin and metalloproteinase with thrombospondin motifs) family. Since lecticans are key regulators of neural plasticity, ADAMTS cleavage of lecticans would likely also contribute to neuroplasticity.

Canonical transient receptor channel 5 (TRPC5) and TRPC1/4 contribute to seizure and excitotoxicity by distinct cellular mechanisms.

Seizures are the manifestation of highly synchronized burst firing of a large population of cortical neurons. Epileptiform bursts with an underlying plateau potential in neurons are a cellular correlate of seizures. Emerging evidence suggests that the plateau potential is mediated by neuronal canonical transient receptor potential (TRPC) channels composed of members of the TRPC1/4/5 subgroup.

Selective decline of synaptic protein levels in the frontal cortex of female mice deficient in the extracellular metalloproteinase ADAMTS1.

The chondroitin sulfate-bearing proteoglycans, also known as lecticans, are a major component of the extracellular matrix (ECM) in the central nervous system and regulate neural plasticity. Growing evidence indicates that endogenous, extracellular metalloproteinases that cleave lecticans mediate neural plasticity by altering the structure of ECM aggregates. The bulk of this in vivo data examined the matrix metalloproteinases, but another metalloproteinase family that cleaves lecticans, a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS), modulates structural plasticity in vitro, although few in vivo studies have tested this concept.

Altered synaptic marker abundance in the hippocampal stratum oriens of Ts65Dn mice is associated with exuberant expression of versican.

DS (Down syndrome), resulting from trisomy of chromosome 21, is the most common cause of genetic mental retardation; however, the molecular mechanisms underlying the cognitive deficits are poorly understood. Growing data indicate that changes in abundance or type of CSPGs (chondroitin sulfate proteoglycans) in the ECM (extracellular matrix) can influence synaptic structure and plasticity. The purpose of this study was to identify changes in synaptic structure in the hippocampus in a model of DS, the Ts65Dn mouse, and to determine the relationship to proteoglycan abundance and/or cleavage and cognitive disability.

Trafficking CD11b-positive blood cells deliver therapeutic genes to the brain of amyloid-depositing transgenic mice.

A major question for gene therapy in brain concerns methods to administer therapeutic genes in a uniform manner over major portions of the brain. A second question in neuroimmunology concerns the extent to which monocytes migrate to the CNS in degenerative disorders. Here we show that CD11b+ cells (largely monocytes) isolated from the bone marrow of GFP (green fluorescent protein)-expressing donors spontaneously home to compacted amyloid plaques in the brain.

Abnormal post-translational and extracellular processing of brevican in plaque-bearing mice over-expressing APPsw.

Aggregation of amyloid-beta (Abeta) in the forebrain of Alzheimer's disease (AD) subjects may disturb the molecular organization of the extracellular microenvironment that modulates neural and synaptic plasticity. Proteoglycans are major components of this extracellular environment. To test the hypothesis that Abeta, or another amyloid precursor protein (APP) dependent mechanism modifies the accumulation and/or turnover of extracellular proteoglycans, we examined whether the expression and processing of brevican, an abundant extracellular, chondroitin sulfate (CS)-bearing proteoglycan, were altered in brains of Abeta-depositing transgenic mice (APPsw - APP gene bearing the Swedish mutation) as a model of AD.

Panel of synaptic protein ELISAs for evaluating neurological phenotype.

The purpose of this study was to develop ELISAs for key neural proteins, three synaptic and one glial, that exist in different intracellular compartments, which would be used as a measure of synaptic phenotype. These assays would be valuable to neurologically phenotype transgenic mouse models of human disease and also human disease itself using minimal amounts of post-mortem tissue. We showed that supernatant from crude brain tissue homogenates extracted in RIPA buffer containing 0.

Suppression of amyloid deposition leads to long-term reductions in Alzheimer's pathologies in Tg2576 mice.

In amyloid precursor protein (APP) models of amyloid deposition, the amount of amyloid deposits increase with mouse age. At a first approximation, the extent of amyloid accumulation may either reflect small excesses of production over clearance that accumulate over time or, alternatively, indicate a steady-state equilibrium at that age, reflecting the instantaneous excess of production over clearance, which increases as the organism ages. To discriminate between these options, we reversibly suppressed amyloid deposition in Tg2576 mice with the anti-Abeta antibody 2H6, starting at 8 months, just before the first histological deposits can be discerned.

Adeno-associated Viral (AAV) Serotype 5 Vector Mediated Gene Delivery of Endothelin-converting Enzyme Reduces Aβ Deposits in APP + PS1 Transgenic Mice.

Reduction of Aβ deposition is a major therapeutic strategy in Alzheimer's disease (AD). The concentration of Aβ in the brain is modulated not only by Aβ production but also by its degradation. One of the proteases involved in the degradation of Aβ peptides is endothelin-converting enzyme (ECE).

Delayed administration of a matrix metalloproteinase inhibitor limits progressive brain injury after hypoxia-ischemia in the neonatal rat.

Background: Hypoxia-ischemia (H-I) can produce widespread neurodegeneration and deep cerebral white matter injury in the neonate. Resident microglia and invading leukocytes promote lesion progression by releasing reactive oxygen species, proteases and other pro-inflammatory mediators. After injury, expression of the gelatin-degrading matrix metalloproteinases (MMPs), MMP-2 and MMP-9, are thought to result in the proteolysis of extracellular matrix (ECM), activation of cytokines/chemokines, and the loss of vascular integrity.

Adeno-associated viral (AAV) serotype 5 vector mediated gene delivery of endothelin-converting enzyme reduces Abeta deposits in APP + PS1 transgenic mice.

Reduction of Abeta deposition is a major therapeutic strategy in Alzheimer's disease (AD). The concentration of Abeta in the brain is modulated not only by Abeta production but also by its degradation. One of the proteases involved in the degradation of Abeta peptides is endothelin-converting enzyme (ECE).

Deglycosylated anti-Abeta antibody dose-response effects on pathology and memory in APP transgenic mice.

Anti-Abeta antibody administration to amyloid-depositing transgenic mice can reverse amyloid pathology and restore memory function. However, in old mice, these treatments also increase vascular leakage and promote formation of vascular amyloid deposits. Deglycosylated antibodies with reduced affinity for Fcgamma receptors and complement are associated with reduced vascular amyloid and microhemorrhage while retaining amyloid-clearing and memory-enhancing properties of native intact antibodies.

Discordant localization of WFA reactivity and brevican/ADAMTS-derived fragment in rodent brain.

Background: Proteoglycan (PG) in the extracellular matrix (ECM) of the central nervous system (CNS) may act as a barrier for neurite elongation in a growth tract, and regulate other characteristics collectively defined as structural neural plasticity. Proteolytic cleavage of PGs appears to alter the environment to one favoring plasticity and growth. Brevican belongs to the lectican family of aggregating, chondroitin sulfate (CS)-bearing PGs, and it modulates neurite outgrowth and synaptogenesis.

Multimodal signaling by the ADAMTSs (a disintegrin and metalloproteinase with thrombospondin motifs) promotes neurite extension.

Aggregating proteoglycans (PG) bearing chondroitin sulfate (CS) side chains associate with hyaluronan and various secreted proteins to form a complex of extracellular matrix (ECM) that inhibits neural plasticity in the central nervous system (CNS). Chondroitinase treatment depletes PGs of their CS side chains and enhances neurite extension. Increasing evidence from in vivo models indicates that proteolytic cleavage of the PG core protein by members of the ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs) family of glutamyl-endopeptidases also promotes neural plasticity.

Versican and brevican are expressed with distinct pathology in neonatal hypoxic-ischemic injury.

The developing brain is uniquely susceptible to injury after exposure to hypoxia-ischemia (H-I). Lecticans are developmentally regulated in formative white matter and exert growth-inhibitory effects in several adult injury models, yet little is known regarding their role in neonatal H-I injury. The main objectives of this study were to examine the expression profiles of brevican and versican in rat using a standard H-I model and to determine whether altered expression was associated with distinct components of white and gray matter pathology.

CD44 adhesion molecule and neuro-glial proteoglycan NG2 as invasive markers of glioma.

Glioma invasion into the CNS involves the interaction of tumor cells with the host's cells and extracellular matrix (ECM) molecules. In this study, the expression of ECM-associated and cell-associated proteins such as the transmembrane CD44 adhesion molecule and neuro-glial proteoglycan 2 (NG2), a member of the chondroitin sulfate proteoglycan family, were evaluated during glioma progression, in vitro and in vivo, using a model of a highly invasive and aggressive intracerebral mouse G-26 glioma. We found a marked increase in CD44 and NG2 expression in brain tissue containing glioma.

Pre-assembled clusters distort crystal nucleation kinetics in supersaturated lysozyme solutions.

Efficient determination of three-dimensional protein structures is critical for unraveling structure-function relationships and for supporting targeted drug design. A major impediment to these efforts is our lack of control over the nucleation and growth of high-quality protein crystals for X-ray structure determinations. While basic research on protein crystal growth mechanisms has provided valuable new insights, studies of crystal nucleation have been plagued by inconsistent and outright contradictory results.

Deglycosylated anti-amyloid-beta antibodies eliminate cognitive deficits and reduce parenchymal amyloid with minimal vascular consequences in aged amyloid precursor protein transgenic mice.

Systemic administration of anti-amyloid-beta (Abeta) antibodies results in reduced parenchymal amyloid but increased vascular amyloid and microhemorrhage in amyloid precursor protein (APP) transgenic mice. Here, we evaluate the effects of reducing effector interactions of the antibody via deglycosylation. Mice aged 20 months were treated weekly for 4 months and tested behaviorally before they were killed.

Intracranial administration of deglycosylated C-terminal-specific anti-Abeta antibody efficiently clears amyloid plaques without activating microglia in amyloid-depositing transgenic mice.

Background: Antibodies against the Ass peptide clear Ass deposits when injected intracranially. Deglycosylated antibodies have reduced effector functions compared to their intact counterparts, potentially avoiding immune activation.

Methods: Deglycosylated or intact C-terminal specific high affinity anti-Abeta antibody (2H6) were intracranially injected into the right frontal cortex and hippocampus of amyloid precursor protein (APP) transgenic mice.

Evidence for proteolytic cleavage of brevican by the ADAMTSs in the dentate gyrus after excitotoxic lesion of the mouse entorhinal cortex.

Background: Brevican is a member of the lectican family of aggregating extracellular matrix (ECM) proteoglycans that bear chondroitin sulfate (CS) chains. It is highly expressed in the central nervous system (CNS) and is thought to stabilize synapses and inhibit neural plasticity and as such, neuritic or synaptic remodeling would be less likely to occur in regions with intact and abundant, lectican-containing, ECM complexes. Neural plasticity may occur more readily when these ECM complexes are broken down by endogenous proteases, the ADAMTSs (adisintegrin and metalloproteinase with thrombospondin motifs), that selectively cleave the lecticans.

Altered production and proteolytic processing of brevican by transforming growth factor beta in cultured astrocytes.

Brevican, a proteoglycan of the lectican family, inhibits neurite outgrowth and may also stabilize synapses. Little is known about its expression or function in vitro. This study seeks to determine whether a brevican-containing matrix is present in neural cultures, and if so, how the production of brevican may be modulated.

The effect of hypoxic-ischemic brain injury in perinatal rats on the abundance and proteolysis of brevican and NG2.

Oligodendrocyte (OL) progenitor cells are particularly susceptible to perinatal hypoxia/ischemia (H-I) resulting in decreased myelination and attenuated development of white matter fiber tracts. Brevican is an aggregating chondroitin sulfate proteoglycan (CSPG) secreted by OLs and their progenitors prior to and during active developmental myelination whereas neuron-glia antigen 2 (NG2) is a transmembrane CSPG produced by early OL progenitors. Although both proteoglycans are associated with maturation of OLs, it is not known if they are altered by H-I brain injury in the neonate.